| 花田 俊也（はなだ としや） | データ更新日：2024.04.15 |
教授 ／
工学研究院
航空宇宙工学部門
宇宙システム工学
| 1. | HARADA Ryusuke, KAWAMOTO Satomi, and HANADA Toshiya, Assessments of the Impacts of Orbital Fragmentations using NEODEEM the Near- earth Orbital Debris Environment Evolutionary Model, The 2nd Intl Orbital Debris Conference, 2023.12, This study evaluated the environmental impacts of orbital fragmentation such as an anti-satellite test, collision between two objects, and explosion. A debris environment evolutionary model named NEODEEM, jointly developed by Kyushu University and JAXA, was used to predict future populations and calculate collision probabilities after a fragmentation. This study focused on characteristics of the fragmented objects, such as altitude, mass, and whether they belong to a Large Constellation (LC). When a fragmentation occurs in higher altitudes, the new fragments will remain in orbit for a long time. Due to this accumulation, the fragments will not only keep the number of objects and probability of collision higher but also cause the risk of secondary collisions between fragments and background objects. When a collision occurs inside an LC at a lower altitude, the impacts will be short-term because most of fragments decay quickly. However, the number of conjunctions, i.e., operational roads, will increase rapidly because many satellites are operated at the same altitude. This study also discussed a collision probability to an LC taking into account the small size of fragments larger than 1 cm.. |
| 2. | Shun ISOBE, Yasuhiro YOSHIMURA, Toshiya HANADA, Yuki ITAYA, and Tadanori FUKUSHIMA, Adaptive Relative Orbit Control Considering Laser Ablation Uncertainty, The 2nd Intl Orbital Debris Conference, 2023.12, This study proposes a relative orbit control law in the laser debris removal method considering the uncertainties of laser ablation and atmospheric drag. A removal spacecraft irradiates laser pulses to a target debris to generate the ablation force for deorbiting. The deorbiting force lowers the target, and the removal spacecraft follows it to maintain its relative position for continuous laser irradiation. In this mission, the difficulty stems from the uncertainties of the magnitude of laser ablation and external disturbances such as atmospheric drag. To tackle this problem, this study derives an adaptive control method using the Gaussian process in which the non-parametric model of the Gaussian process can cancel the uncertainties. Numerical simulations verify the proposed control law under the uncertainties. The proposed control law can contribute to the realization of safer and more secure mission not only for laser debris removal method but also for other debris removal methods and on-orbit services.. |
| 3. | Ai HAYASHIBARA, Yasuhiro YOSHIMURA, Toshiya HANADA, Yuki ITAYA, and Tadanori FUKUSHIMA, Improved Contactless Attitude Control Law of Uncooperative Spacecraft by Laser Ablation, The 2nd Intl Orbital Debris Conference, 2023.12, This paper proposes an attitude control method to remove uncooperative spacecraft by laser ablation. To efficiently deorbit space debris using laser ablation, it is necessary to control the attitude motion of the target in advance. A previous attitude controller empirically determines control gains and is easily affected by assumed preconditions. To address this issue, this study proposes an improved attitude control law using laser ablation. By analogy with a magnetic attitude control law, theoretical conditions for designing the control gains are obtained. Numerical examples using the proposed control law are conducted to control the attitude from a random initial rotation of 1 rpm to an arbitrary attitude, which verify the effectiveness of the proposed method.. |
| 4. | Yuki ITAYA, Yasuhiro YOSHIMURA, Toshiya HANADA, and Tadanori FUKUSHIMA, Less Fuel Strategies for Space Debris Removal in Low Earth Orbit, The 2nd Intl Orbital Debris Conference, 2023.12, This paper proposes less fuel strategies for space debris removal. To mitigate the risk of space debris cost-efficiently, multi-rendezvous missions are under development. On the other hand, multi-rendezvous missions often require changing orbital planes of removal satellites, which requires a huge amount of ΔV. Therefore, this study focuses on exploiting the J2 perturbation force as an auxiliary force and aims to establish maneuver rules that minimize ΔV consumption while maximizing the benefit of the J2 perturbation. The J2 perturbation equation is explored analytically, which clarifies whether the change in the semi-major axis or the inclination dominates the efficiency of the exploitation. A straightforward criterion is extracted which determines the efficient maneuver based on the initial inclination of the satellite.. |
| 5. | 奥平清明，花田俊也，中島健介，吉村康広, ロシア放送衛星EKRAN 2破砕破片の光学観測とその考察, 日本航空宇宙学会西部支部講演会(2023), 2023.12, This paper investigates traklets observed by the Pegasus Observatory at Kyushu University, Fukuoka. First, this paper associates the tracklets with a fragment from the on-orbit fragmentation of the Russian EKRAN 2 spacecraft by using a Plate Solving method. Second, since the light intensity along the tracklets change significantly over a short exposure time, this paper concludes the possibility that the fragment may be rotating rapidly.. |
| 6. | 服部慶士郎，棚橋茉拓，陳泓儒，吉村康広，花田俊也, 微小デブリ計測衛星による破砕起源の同定, 日本航空宇宙学会西部支部講演会(2023), 2023.12, This paper verifies whether some orbital parameters of on–orbit satellite fragmentations can be estimated from in–situ debris measurements conducted in elliptic orbits passing through a given altitude range. Previous studies have verified that some orbital parameters of a broken–up object in a circular orbit can be identified when in–situ debris measurement were conducted in circular orbits. For this study, in–situ debris measurements are assumed to be conducted in two elliptical orbits passing through altitudes of 600 km to 800 km and 800 km to 1000 km.. |
| 7. | 藤田浩輝，渡邉陸，小川泰信，花田俊也, 破砕物体群をターゲットとする観測計画立案手法の有効性についての検証, 日本航空宇宙学会西部支部講演会(2023), 2023.12, This paper evaluates efficiency of an observation plan for a group of fragmentation debris generated from specific breakup events in low-earth orbit. In this work, space objects detected by an atmospheric radar system called EISCAT Svalbard Radar (ESR) are treated. After consideration of propagation errors utilizing orbital elements in a two- line element set (TLE) including various epochs, an effectiveness of the planning method based on observation directions with high density of propagated orbits of the fragmentation debris is described. Results from a correlation analysis for the observation data obtained from a campaign in 2019 finally verifies practical effectiveness of the proposed planning method.. |
| 8. | Satomi Kawamoto, Ryusuke Harada, Yasuhiro Kitagawa, Toshiya Hanada, Evaluation of the Effectiveness of 5-year Rule -- Impact on the Orbital Environment at Each Altitude by Reducing the Post-mission Disposal Lifetime, The 74th Intl Astronautical Congress, 2023.10, This paper examines the effect of shortening the post-mission disposal lifetime, i.e., changing the so- called 25-year rule to 5-year rule. Using NEODEEM, debris evolutionary model developed by Kyushu University and JAXA, we evaluated the change in the on-orbit environment at each altitude in terms of long-term stability and short-term safety such as the number of collision avoidance maneuvers and the collision rate. When evaluated in terms of the long-term total effective number of on-orbit objects, the 25-year rule is sufficiently effective and has been adopted in consideration of the balance with the V required for orbit transfer. However, it is not appropriate to evaluate only by the effective number of objects. For example, the greater the effective number in the low orbit in the initial state, the fewer the overall number appears to increase due to the cancellation of the effect of their decay from the lower altitude and their tendency to increase at high altitude, but in reality, the situation is different at each altitude. Thus, it is necessary to evaluate not only the effective number of objects but also the collision rate, etc. at each altitude in order to assess long-term stability. In addition, if the number of launches increases beyond what has been assumed, it would be necessary to evaluate its impact. It is shown the collision rate at an altitude of around 600 km will increase if the number of launches to high altitude and the PMD compliance rate increases, although the impact of collision is not long term. In the short term, the 5-year rule reduces the collision rate and collision avoidance frequency at an altitude around 600 km more than the 25-year rule. Similarly, if the number of spacecraft descending to an altitude of around 500 km increases due to the 5-year rule, the collision rate and the expected number of collision avoidance maneuvers for the ISS, for example, will increase in the very short term. However, if the 5-year rule is not applied instead of the 25-year rule, and subsequent collisions occur at altitudes around 600 km, the collision rate and expected number of collision avoidance maneuvers will increase later because the fragments fall to a lower altitude. This suggests that the post mission disposal lifetime should be set according to the number and size of objects launched.. |
| 9. | HARADA Ryusuke, KAWAMOTO Satomi, and HANADA Toshiya, Establishment of Debris Index Evaluation Criteria and Comparison of Index Effects, The 74th Intl Astronautical Congress, 2023.10, Space debris index is a measure to assesses the environmental impacts of a spacecraft or a mission, and there have been many studies and controversies on its utilization and formulation. Especially, the index formulation is a topic that has many productive studies to accurately represent the impact of the target object or mission on the orbital environment. It is estimated that the higher the value of the index calculated based on the mass of the spacecraft or mission orbit, the greater the impact of the index. However, it is not clear whether a 10-fold increase in the index value will result in a 10-fold deterioration of the environment. Therefore, it is necessary to establish some criteria for evaluating the effect of the index; what changes are good or bad for the orbital environment. This paper discusses the steps which should be taken to establish debris indices that can be widely and easily used by operator, companies, and other stakeholders. These steps are divided into two categories, definitions of criteria and formulations of debris indices. By providing the criteria, the relationship between the value of index and environmental impacts of spacecraft or missions would be revealed. Such criteria also would compare the effects of different indices from the same perspective. Moreover, some specific thresholds of the index could be set taking into accounts orbital capacity. This paper discusses which criteria, such as effective numbers of objects, a collision probability, and a number of conjunctions that are generally used to show the environmental predictions, are suitable for understanding the effects of debris indices. The formulations of space debris indices are also important for widely and easily uses of indices. Currently, some organizations which have debris environment evolutionary models assess spacecraft or mission’s environmental impacts using their models. If debris indices are defined by simple components such as spacecraft’s mass, orbital lifetime, and collision probability, indices assessments would be easily conducted without using debris evolutionary model. In order to formulate such simple index, comparison of indices effects through evaluation of debris evolutionary models is needed. This paper proposes some indices that can be evaluated using evolutionary model, and assesses their short/long-term impacts by criteria proposed in this study. This paper also proposes the indices defined by simple components, and assesses whether the formulas are essentially the same evaluation with indices which use evolutionary model.. |
| 10. | 棚橋茉拓，花田俊也，江口菜穂, 中規模大気現象の観測に適した小型衛星コンステレーションの設計, 第67回宇宙科学技術連合講演会講演集, 2023.10, This paper proposes a design method for a constellation of satellites. Aiming at improving the prediction accuracy of meteorological disasters (e.g., typhoons, linear rainbands, etc.), observation missions using a constellation of satellites, targeting the East Asian region including Japan have been proposed. An ultra-low orbit is desired from the viewpoint of resolution and weight of the observation equipment, but in general, the swash width from an ultra-low orbit is narrow and it is difficult to observe a specific area at a high frequency. Therefore, this paper proposes the design of a constellation that can observe a specific area with high frequency even with a small satellite in an ultra-low earth orbit.. |
| 11. | 五十部駿，吉村康広，花田俊也，板谷優輝，福島忠徳, 不確実な外乱加速度下でのガウス過程回帰を用いた相対軌道制御, 第67回宇宙科学技術連合講演会講演集, 2023.10, This study proposes the relative orbit control law considering uncertainties of disturbance force. The relative orbit control of a spacecraft about non-cooperative objects is an promising technology for future on-orbit servicing and debris removal missions. The uncertainties of disturbance force may increase the relative position error, resulting in a high risk of collision. To tackle this problem, this study derives an adaptive control method using Gaussian process. Gaussian process is a data-driven machine learning model and is suitable for function regression problems. Furthermore, Gaussian process can learn non-parametric models and cancel the uncertainties in control architecture. Numerical simulations verify the proposed control law under differential drag.. |
| 12. | 中島健太，吉村康広，陳泓儒，花田俊也, 宇宙広告フォーメーションの特異点問題とドリフト安定性, 第67回宇宙科学技術連合講演会講演集, 2023.10, This paper solves a singular problem to stabilize a space-advertisement formation. The space advertisement is a dot matrix illuminating in the night sky seen from the ground. Using multiple satellites with light sources, the arbitrary dot matrix can be made by considering relative apparent position of each dot from a representative dot. This study solves a singular problem of a coordinate system which describes the positions of the dots to finally stabilize the dot matrix. This study introduces a new topocentric coordinate system to solve the singular problem and formulates the relative apparent position of the dot as linear functions. The formulation generally describes the relative apparent position of satellites seen from the ground. The proposed formulation reveals a stability of the dot matrix as well as solving the singular problem. The stability of the dot matrix is decomposable into six coefficients related to a set of relative orbital elements. Considering the characteristics of the six coefficients, a stable condition is revealed. Even with semi-major axis difference, the dot matrix can be stabilized during a visible span.. |
| 13. | 藤田浩輝，有吉雄哉，吉村康広， 小川泰信，花田俊也, EISCAT レーダー観測データを用いたカタログ物体に基づく特徴分類, 第67回宇宙科学技術連合講演会講演集, 2023.10, This paper proposes a method to classify LEO objects detected via EISCAT radar, based on orbital characteristics of the fragmentation debris originated from different breakup events. Since many of the detected objects can be identified with the known cataloged objects, most of them can also be classified as one of the groups of debris correlated to specific breakup events. In this paper, aided by a concept of Admissible Region, a classification method for the radar observation objects in LEO is derived and applied to results of an observation campaign in 2022.. |
| 14. | 梶川拓海，吉村康広，陳泓儒，花田俊也, デュアルクォータニオンによる姿勢・形状を考慮した接近解析手法, 第67回宇宙科学技術連合講演会講演集, 2023.10, This paper proposes a close approach analysis method considering the attitude motion of two colliding objects. De- tailed close approach analysis is important because the number of space objects has been increasing in recent years. Conventional conjunction assessments assume two colliding objects to be point masses with no volume, but they are ob- jects with volume. In the proposed method in this paper, the first step calculates the time of close approach considering two objects as point masses. Next step chooses two poses (i.e., attitude and position) when the distance becomes less than a given threshold, and the third step interpolates the two poses using dual quaternions. Dual quaternions can de- scribe the translational and rotational motions, which ensures the uniquness of the interpolation. Numerical simulations are conducted to verify the proposed method and compre it with a conventional method.. |
| 15. | 原龍依，吉村康広，陳泓儒，花田俊也, ガウス過程回帰を用いた姿勢とライトカーブ回帰モデルの評価, 第67回宇宙科学技術連合講演会講演集, 2023.10, This study proposes a nonparametric regression model to describe the attitude motion of space objects. Understand- ing the attitude of space objects is crucial for accurate orbit propagation. Light curve inversion is known as one of the methods of space objects ’attitude inference. However, previous studies have assumed known shapes for the estimation. Thus, this paper constructs nonparametric attitude and light curve models without shape information using Gaussian process regression. The shape of space objects is implicitly learned from the attitude differences that stem from dis- turbance torques, i.e., solar radiation pressure torques in this paper. Numerical examples include three types of object shape and evaluate the regression models.. |
| 16. | 林原愛，吉村康広，花田俊也，板谷優輝，福島忠徳, レーザアブレーションによる非協力衛星の姿勢制御, 第67回宇宙科学技術連合講演会講演集, 2023.10, This paper proposes an attitude control method of an uncooperative spacecraft using lasers. The attitude motion of the spacecraft must be controlled in advance for space debris removal by laser ablation. The control gain in a conven- tional attitude control law is empirically given and is sensitive to assumed preconditions. Thus, this paper improves the conventional attitude control law by providing a method to theoretically obtain the control gain by setting a reference torque based on the angular momentum error. Numerical simulations verify the effectiveness of the control gain designed and robustness against gravity gradient torques and solar radiation pressure torques.. |
| 17. | Nagisa INOKUCH, Hidehiro HATA, Kumi NITTA, Toshiya Hanada, Investigation into Fragmentation of the Russian EKRAN 2 Spacecraft, The 34th International Symposium on Space Technology and Science, 2023.06, This paper investigates the on-orbit satellite fragmentation of the Russian EKRAN 2 spacecraft, which exploded due to dead batteries in June 1978. This paper reviews the longitudinal perturbation of fragments and hypothesizes that gas and fragments from dead batteries placed outside may push the main body to release appendages such as solar array paddles. To verify this hypothesis, therefore, this paper conducts two explosive fragmentation experiments using two identical mock-up satellites. One has a PETN explosive inside the main body, whereas another has the same explosive outside the main body. When the PETN explosive was inside the main body, the mock-up satellite was completely fragmented to release many fragments. If the PETN explosive was outside the main body, on the other hand, only a hole was made on the exterior wall where the PETN explosive was placed to release only fewer small fragments. Therefore, this paper concludes that gas and fragments from dead batteries placed outside pushed the main body to release appendages. . |
| 18. | Masaharu MORIOKA, Ryuji NAKAWATASE, Yasuhiro YOSHIMURA, Toshiya HANADA, Ryusuke HARADA, Satomi KAWAMOTO , Update of NEODEEM the Near-earth Orbit Debris Environmental Evolution Model, The 34th International Symposium on Space Technology and Science, 2023.06, This paper briefly introduces the update of NEODEEM the Near-earth Orbit Debris Environmental Evolution Model. NEODEEM was jointly developed by Kyushu University and JAXA to track near-earth space objects. NEODEEM has contributed to the worldwide effort not only to predict the future space debris population but also as an indispensable tool to identify effective measures for space debris mitigation and environmental remediation. The update introduced in this paper includes its orbit propagation and collision probability evaluation algorithm. . |
| 19. | 棚橋茉拓，陳泓儒，吉村康広，花田俊也, 微小デブリ観測衛星を用いた破砕起源の推定, 第66回宇宙科学技術連合講演会, 2022.11, This paper briefly introduces a new approach to estimate some orbital parameters of on-orbit satellite fragmentations (specifically, the direction of angular momentum at a specific time and its time change) from in-situ debris measurements. Previous studies have applied a nonlinear least-square method to a constraint equation derived from the fact that a piece of debris detected shares the geocentric position vector with an in-situ debris measurement satellite. However, the new approach applies a nonlinear model fit to the history of geocentric declination at the time of detection. This paper also verifies that the new approach works effectively under ideal conditions where all detections are assumed to be at the line of intersection of the two orbital planes of a broken-up object and an in-situ debris measurement satellite.. |
| 20. | 清水貴裕，吉村康広，河本聡美，花田俊也, 気候変動を考慮した宇宙開発の持続可能性評価, 第66回宇宙科学技術連合講演会, 2022.11, There is a growing concern about climate change caused by greenhouse gases. Especially, carbon dioxide has significant influences not only on the lower atmosphere but also on the upper atmosphere such as the thermosphere where space objects are orbiting. One of the problems of increasing carbon dioxide is that it reduces the density of the thermosphere, resulting in less drag on space objects. This paper evaluates the influence of decreasing the air drag by an orbital debris evolutionary model. In this study, the motion of space objects is calculated by considering the reduction of atmospheric density in the Jacchia-Roberts 1971 atmospheric model.. |
| 21. | 高橋雄文，花田俊也，酒向重行, Tomo-e Gozenの観測データからみる静止軌道帯の宇宙デブリ環境, 第66回宇宙科学技術連合講演会, 2022.11, This paper mainly investigates potentials of the “Tomo-e Gozen” system on 1.05 m Kiso Schmidt telescope to be a significant tool for searching missing space debris towards a sustainable space activity. The system is featured by its wide-field and high-cadence videos observations with mosaic CMOS sensors. This paper conducts the investigation through comparing the Tomo-e Gozen's observation data of breakup-originated debris and an observation path based on prediction of the debris population. That work made it clear that the system is useful enough for searching missing space debris. It is also recognized that a long-term observation is needed to complete the task. As well as those results, plotting observation data of uncorrelated target (UCT) objects on a celestial sphere, we confirmed path-like curves which maybe lead to tracking the UCT objects.. |
| 22. | 浦志太勢，坂東麻衣，吉村康広，陳泓儒，花田俊也，外本伸治, データ駆動型解析による地球–月三体問題におけるカオス軌道の解析, 第66回宇宙科学技術連合講演会, 2022.11, Low-energy transition orbits in the Earth-Moon three-body problem are known to be chaotic in nature, hence orbit prediction and design are difficult. In this study, in order to predict chaotic behavior, a new method is proposed to approximate high-dimensional chaotic transition trajectories as maps of low-dimensional periapsis maps by dynamic mode decomposition, which is a data-driven approach. Moreover, comparing the approximation errors caused by this method with the dynamical structure of the circle-restricted three-body problem, it is found that orbits with large approximation error are on the boundary of the dynamical structure, therefore the proposed method also leads to the clarification of the dynamical structure of the chaotic orbits.. |
| 23. | 正木翔，吉村康広，陳泓儒，花田俊也, 高精度太陽輻射圧モデルを適用した衛星姿勢ダイナミクスの解析, 第66回宇宙科学技術連合講演会, 2022.11, Solar radiation pressure (SRP) is a major disturbance for a spacecraft operated in deep space missions, affecting its orbit and attitude, and high accuracy of SRP calculation is required. SRP calculations are affected by the shape and surface characteristics of the satellite. However, existing computational models do not sufficiently take into account the exact reflective properties of the satellite surface. A detailed reflection model and considering the optical characteristics yield a different SRP and its torque from the conventional ones, resulting in a different attitude motion. In this study, an SRP calculation method that considers exact reflective properties is applied to investigate attitude dynamics using high-fidelity SRP.. |
| 24. | 五十部駿，吉村康広，花田俊也，板谷優輝，藤原智章，福島忠徳, 非協力物体との同時軌道離脱フォーメーションキーピング, 第66回宇宙科学技術連合講演会, 2022.11, This paper proposes a control law for simultaneous deorbit using laser ablation. Laser ablation is a vital technology for contactless active debris removal, where a service satellite with a laser system irradiates a target satellite to generate the ablation force for deorbiting. The deorbiting force decelerates the target, and the service satellite must maintain its relative position and continue irradiating. The difficulty of simultaneous deorbiting stems from the relative motion between the service satellite and the target in powered flight because conventional formation flying missions assume that only a service satellite maneuvers. This paper derives the relative equations of motion between the service satellite and the target in powered flight. A control law for the simultaneous deorbit is proposed, which determines the timing and direction of the laser ablation and the electrical thrust so that the formation periodically returns to the desired formation. Numerical simulations are performed for two test cases to verify the control law involving the uncertainties of thrust magnitude.. |
| 25. | 吹井柊太，吉村康広，陳泓儒，花田俊也, デュアルクォータニオンを用いた姿勢軌道推定, 第66回宇宙科学技術連合講演会, 2022.11, On-orbit servicing, where a service satellite performs missions such as life-extension or deorbit of a target satellite, has been planned by many commercial entities. Relative pose estimation (i.e., attitude and orbit estimation) is essential to conduct on-orbit servicing missions successfully because the target satellite is noncooperative in many practical cases. This paper proposes a satellite pose estimation method that allows us to conduct a more accurate and efficient estima- tion using the unscented Kalman filter (UKF). There is a significant advantage in estimating both attitude and orbit motion simultaneously because they are coulle in general. To this end, the unified parameterization of both attitude and orbit using dual quaternions is applied in this paper. Employing the dual quaternions in the UKF, however, has a difficulty that stems from the algebraic constraints of the dual quaternions. That is, the algebraic constraints of dual quaternions are violated when calculating the weight-mean dual quaternion in the UKF sequence. This paper proposes and compares the following two methods to compute the averaged dual quaternion: 1) dual quaternion linear blending and 2) dual quaternion averaging. These two methods allow us to calculate the weight-mean dual quaternions while keeping the algebraic constraints. Numerical examples for relative pose estimation are conducted to discuss the accuracy and effectiveness of the proposed methods.. |
| 26. | 井ノ口凪紗，中野亮，波多秀寛，，花田俊也, 模擬人工衛星の爆発破砕実験方法に関する基礎研究, 第66回宇宙科学技術連合講演会, 2022.11, This paper provides experiment results of a satellite fragmentation due to battery. The current explosion model in the NASA standard breakup model is based on the outcome of rocket upper stage explosions. The NASA breakup model may not be able to describe the physical properties of fragments from satellite battery-induced explosions, however. Therefore, this study conducts satellite battery-induced explosions using mock-up satellites. To simplify the experiment, an 1 g of PETN explosives were used instead of batteries. The explosion experiments were filmed by a high-speed video camera. The delta-velocity of the fragments were obtained from these images. The target satellite was completely fragmented after the experiments. Approximately 40,000 fragments were collected. Each fragment was measured and analyzed based on the methods proposed in the NASA standard breakup model. The size, average cross-sectional area, area-to-mass ratio, and delta-velocity distributions were compared with the NASA standard breakup model.. |
| 27. | 花田俊也，波多英寛, ロシア放送衛星 EKRAN 2 の破壊モードについて, 日本航空宇宙学会西部支部講演会（2022）, 2022.11, This paper investigates on-orbit satellite fragmentations in the geostationary region. First, this paper reviews the on-orbit fragmentation of a US TITAN 3C TRANSTAGE based on a previous study and indicates that it was a relatively major fragmentation. Second, this paper reviews the on-orbit fragmentation of the Russian EKRAN 2 spacecraft based on longitudinal perturbation and indicates that it was a relatively minor fragmentation. Finally, this paper concludes that the gas and fragments generated by the burst of batteries placed outside pushed the main body to release appendages such as solar array paddles.. |
| 28. | 波多英寛，井ノ口凪紗，花田 俊也, 内部爆発エネルギーによる衛星破壊への影響評価, 日本航空宇宙学会西部支部講演会（2022）, 2022.11, A fragmentation model representing the situation at the time of generation is necessary for the prediction of the space debris environment. Explosive fragmentation is one of the causes of space debris generation. Explosive fragmentation produces more space debris. Therefore, in this study, an explosion fragmentation experiment using a small mock-up satellite was performed. A PETN explosive installed inside the small mock-up satellite was used as the explosion source. The fragments were collected and photographed with a high-speed camera. This paper reports the results obtained by examining the difference in internal explosive energy and the results obtained with the NASA standard break-up model.. |
| 29. | 藤田浩輝，有吉雄哉，吉村康広， 小川泰信，花田俊也, EISCATレーダー観測データを用いた既知物体との相関解析, 日本航空宇宙学会西部支部講演会（2022）, 2022.11, This paper describes an analysis of radar observation data detecting space objects in low-earth orbit (LEO), which are correlated to cataloged ones. In this work, the objects detected by an atmospheric radar system called EISCAT Svalbard Radar (ESR) are treated. During the observation campaign in March of 2022 (total 14 hours for two days), about 7 hundred hard targets were detected through the radar facility. This paper shows the results of a correlation analysis between the detected objects and known and tracked ones, or so-called cataloged objects, and discusses them from a viewpoint of identification for space debris generated via collisions and explosions in orbit.. |
| 30. | 中島健太，吉村康広，陣泓儒，花田俊也, 宇宙広告衛星のフォーメーション安定化, 日本航空宇宙学会西部支部講演会（2022）, 2022.11, The space-advertisement mission gives an artificial constellation in the night sky using a satellite formation with light sources. The formation shape observed from the ground which was not discussed by previous studies is revealed. A proper design of satellites using present equations makes an arbitrary advertisement shape. Moreover, some stable orbits whose advertisement shape can be kept during the visible span are revealed, which makes a stable advertisement design without control.. |
| 31. | 藤田浩輝，有吉雄哉，吉村康広，小川泰信，花田俊也, EISCAT レーダー観測データを用いた既知デブリ との相関解析, 第10回スペースデブリワークショップ, 2022.11, This paper describes an analysis of radar observation data detecting space objects in low-earth orbit (LEO), which are correlated to cataloged ones. In this work, the objects detected by an atmospheric radar system called EISCAT Svalbard Radar (ESR) are treated. When the objects observed in March of 2022 (totally 14 hours for two days) were applied to the correlation analysis, sixty percent of the observed objects were highly correlated with all the cataloged objects including space debris, which are known and constantly tracked. This paper investigates altitudes and sizes of the correlated and uncorrelated objects, respectively, as well as discusses cause of the lack of correlation and problems how to identify the uncorrelated objects.. |
| 32. | 棚橋茉拓，吉村康広，藤田浩輝，花田俊也, 微小デブリ観測衛星を用いた破砕起源の推定, 第10回スペースデブリワークショップ, 2022.11, This paper briefly introduces a new approach to estimating some orbital parameters of on-orbit satellite fragmentations (precisely, the direction of angular momentum at a specific time and its time change) from in-situ debris measurements. Previous studies have applied a nonlinear least-squares fitting to a constraint equation derived from the fact that a piece of debris detected shares the geocentric position vector with an in-situ debris measurement satellite. However, the new approach applies a nonlinear least-squares fitting to the history of geocentric declination at the detection time. The previous studies have been verified under ideal conditions where all detections are assumed to be at the intersection of the two orbital planes of a broken-up object and an in-situ debris measurement satellite. However, this study verifies using more realistic measurements from a close approach analysis.. |
| 33. | 波多英寛，井ノ口凪紗，仁田工美，佐藤健一，花田俊也, 模擬衛星を用いた爆発源位置による影響評価と実例による考察, 第10回スペースデブリワークショップ, 2022.11, The Breakup model includes cases of collisions and explosions, and this study examines the breakup model for satellite explosions. Explosive fragmentation experiments were conducted using a mock-up satellite in a simple vacuum vessel. Then, the fragment size and typical velocity are measured using the high-speed photographing results and recovered fragments after the experiment, and an explosion breakup model is examined. A PETN explosive has predictable explosive energy and is used as the explosion source. This presentation compares the results obtained by changing the location of the explosion source inside and outside the mock-up satellite. Then, the effect of the location of the explosion source on the broken condition and the breakup model is examined. And It is reported that different results were obtained depending on the location of the explosion source. In addition, the situation of Ekran2 and its fragments was examined as a case of a breakup. As a result, the source of the explosion may be outside.. |
| 34. | 長岡信明，河本聡美，原田隆佑，北川康弘，花田俊也, 軌道上デブリ推移モデルを用いた 軌道上破砕片の推移解析, 第10回スペースデブリワークショップ, 2022.11, JAXA has been evaluating the future space debris environment using a debris evolutionary model named NEODEEM, developed in collaboration with Kyushu University. This evolutionary model is able to generate orbital debris generated by on-orbit collisions and explosions, and also to estimate and evaluate the impact of debris on the long-time orbital environment. In addition, by using this model, ASAT events also may simulate and evaluate, which has become a problem in recent years, can also be simulated. In this presentation, various analysis examples based on this evolutionary model are introduced.. |
| 35. | 清水貴裕，吉村康広，河本聡美，原田隆佑，花田俊也, 大気上層の長期変動を考慮した 宇宙開発の持続可能性評価, 第10回スペースデブリワークショップ, 2022.11, There is a growing concern about climate change caused by greenhouse gases. Especially, carbon dioxide has significant influences not only on the lower atmosphere but also on the upper atmosphere such as the thermosphere where space objects are orbiting. One of the problems of increasing carbon dioxide is that it reduces the density of the thermosphere, resulting in a less atmospheric drag on space objects. This paper evaluates the long-term influence of decreasing the atmospheric drag on the space environment and space activities using an orbital debris evolutionary model. In this study, Jacchia-Roberts 1971 atmospheric model is used to calculate the atmospheric density. In addition, this study makes corrections to atmospheric density with considering the long-term density decrease. This paper also reveals the long-term impact of density decrease on space activity by calculating the debris number transition, the extension of debris orbital lifetime, and collision probability with debris. Furthermore, this study shows the change of delta-v and the collision probability with other objects to satisfy the 25-year rule.. |
| 36. | 原田隆佑，河本聡美，長岡信明，花田俊也, スペースデブリインデックスの活用及び 定式化に関する検討, 第10回スペースデブリワークショップ, 2022.11, This presentation describes the status of the Space Debris Index study by the debris modeling team of JAXA's Research and Development Directorate. The debris index which indicates the environmental impact of spacecraft or missions has been the subject of international discussion and research. The modeling team organized the definitions and applications of the debris index and summarized which characteristics of the environmental impact of spacecraft should be evaluated. From this result, we narrowed down the features to be considered, and are working on an index formulation. The index is formulated in terms of short-term and long-term effects on the orbital environment. The environmental evaluation criteria are also discussed to confirm that the index values correctly represent the impact of spacecraft on the orbital environment. This presentation also shows the effect of environmental improvement using the debris index. The objects in the orbit are evaluated based on several indices, and the top 50 objects are removed from the orbit.. |
| 37. | 板谷優輝，福島忠徳，Aditya Baraskar，藤原智章，長峯健心，五十部駿，吉村康広，花田俊也, レーザ衛星を用いた ADR ミッションにおける軌道設計, 第10回スペースデブリワークショップ, 2022.11, As the number of spacecraft and orbital debris is rapidly increasing, Active Debris Removal is becoming an essential technology to maintain a sustainable space environment. SKY Perfect JSAT and RIKEN are developing a laser-equipped ADR satellite that adopts laser ablation technology to generate a thrusting force on the target object. This ADR method does not require any physical contact with the target object, which is a remarkable characteristic compared to the widely proposed methods. The laser satellite can perform detumbling and deorbiting of the target object as long as its relative distance is within the laser range. For that reason, docking or capturing is no longer needed for this ADR method. On the other hand, proximity operations need to be considered over the entire mission period. ADR mission provided by Laser satellite can be divided into several phases, such as detumbling phase and deorbiting phase, and each phase requires individual orbit design. This presentation will show the concept of the orbital design for each mission phase and provides the validation results by using Hill coordinate systems and relative orbital elements.. |
| 38. | 五十部駿，正木翔，吹井柊太，吉村康広，花田俊也，板谷優輝，藤原智章，福島忠徳, レーザアブレーションを用いたマルチデオービット の相対軌道設計, 第10回スペースデブリワークショップ, 2022.11, To remediate the orbital environment, active debris removal (ADR) from low Earth orbit is required. Laser ablation is a vital technology for contactless active debris removal, where a service satellite irradiates laser pulses to a target satellite to generate the ablation force for deorbiting. Since the ADR method using a laser requires no deorbiting device to attach, the ADR by laser enables simultaneously deorbiting multi-targets, which is a promising ADR technology. As a preliminary study of multi-deorbit, this paper designs the formation with respect to multi-targets to maximize the laser duration or minimize collision probability. Furthermore, the laser system has significant constraints such as laser focal length, laser irradiating angle, and camera angle. Thus, the designed formations must satisfy the constraints of the laser system. To this end, two formations that require attitude control or no attitude control are proposed. Their performances are compared in terms of safety and deorbit efficiency.. |
| 39. | Ryusuke Harada, Satomi Kawamoto, Nobuaki Nagaoka, Toshiya Hanada, The Impact Assessment of Accidental Explosions of Large Constellations on Low Earth Orbit Environment, The 73rd Intl Astronautical Congress, 2022.09, Because of its large number of satellites, a large constellation (an LC) greatly affects other objects in LEO. Several studies reveal the impact of an LC in LEO missions in various operational scenarios. This study evaluated the environmental impact of an LC explosion in the short- and long-term using the Near-Earth Orbital Debris Environment Evolutionary Model (NEODEEM). Although setting mission scenarios and analysis conditions is important in LC simulations, it is difficult to consider all operational scenarios due to the many combinations. Therefore, this study conducted impact assessments of explosions in an LC, concentrating on the number of explosions, orbital altitude, and scaling factor of the explosions. The results indicated that it is not enough for LC to comply with the current requirement of probability of accidental explosions which is less than 0.001 during the operation. This is because, if the rate is applied directly to an LC with thousands of satellites, continuous explosions (i.e., several satellites explode every year) will occur during the duration of LC. The paper also discusses the behavior of fragments from explosions at different altitudes. The explosions at low altitudes have no significant impact in the long term, although it can cause an incremental change in collision risk in the short term. Similarly, the explosions at high altitudes, such as 1,250 km, have only slightly increments of the expected number of collisions, but its impact could last for over 100 years. The probability of explosions of an LC must be carefully determined through a series of simulations based on the number of satellites and the operational orbit of an LC. This paper also discusses what should be considered in future LC design and operations regarding explosion prevention.. |
| 40. | Aditya Baraskar, Tadanori Fukushima, Yuki Itaya, Tomoaki Fujihara, Kenshin Nagamine, Katsuhiko Tsuno, Yoshiharu Kawai, Masayuki Maruyama, Takayo Ogawa, Satoshi Wada, Toshikazu Ebisuzaki, Marco Casolino, Daisuke Sakai, Yasuhiro Yoshimura, Toshiya Hanada, Laser based Active Debris Removal Technology for ENVISAT, The 73rd Intl Astronautical Congress, 2022.09, The 21st century is marked by the unprecedented progress of human knowledge in space, quantum mechanics, and machine learning. This progress has in turn lead to a significant increase in satellite launches, with various organizations developing mega-constellations in space to provide new business opportunities. While current predictions estimate that space in Low Earth Orbit will be overcrowded in the future, and sustainability of space will become a critical question as the estimated traffic of 89,000 satellites will be launched by the year 2035. To allow sustainable development of space, especially in Low Earth Orbit, there is a need to develop accurate traffic management and active debris removal mission planning. Lately, several organizations proposed and completed space demonstration experiments for debris removal. Current their designs are part of an ongoing project to develop contact- based debris removal technology. However, this technology poses several problems for satellite removal. We propose a complementary method based on a laser system. The laser is capable to operate from a safe distance by stopping the continuous rotation (detumbling) of space objects. In this paper, we present a case study using the ENVISAT satellite. ENVISAT is an 8,211 kg satellite, launched by European Space Agency. Since 2012, communication has stopped, and it is no longer operational. It is predicted to self-deorbit in the next 150 years. However, the orbital simulation of existing objects found two cataloged space debris which will pass within 200 m., resulting in a close approach every year. The elevated mass of the satellite and the number of close approaches, therefore, pose a considerable threat, leading to the production of debris. SKY Perfect JSAT Corporation is working jointly with Japanese institutions to collaboratively develop laser satellites to stop detumbling and the careful removal of debris. The demonstration mission will be launched by the year 2026-2027. With this case study, a laser-based contactless method can be practiced for removing mega debris like ENVISAT from the Low Earth Orbit.. |
| 41. | Shun Isobe, Yasuhiro Yoshimura, Toshiya Hanada, Yuki Itaya, Tadanori Fukushima, Formation Keeping Control For Simultaneous Deorbit Using Laser Ablation, The 73rd Intl Astronautical Congress, 2022.09, Laser ablation is a vital technology for contactless active debris removal, where a service satellite with a laser system irradiates laser pulses to a target satellite to generate the ablation force for deorbiting. The deorbiting force decelerates the target, and the service satellite needs to maintain its relative position and keep irradiating. In other words, both the service satellite and the target are supposed to be deorbited simultaneously, where both satellites have accelerations. The difficulty of simultaneous deorbiting stems from the relative motion between the service satellite and the target in powered flight because conventional formation flying missions assume that only a service satellite maneuvers. This paper derives the relative equations of motion between the service satellite and the target in powered flight. A control law for the simultaneous deorbit is proposed, which determines the timing and direction of the laser ablation and the electrical thrust so that the formation periodically returns to the desired formation. Numerical simulations are performed for two test cases to verify the control law under the uncertainties of thrust magnitude and orbital perturbation.. |
| 42. | Mahiro Tanahashi, Hongru Chen, Yasuhiro Yoshimura, Toshiya Hanada, Estimation of Orbital Parameters of Broken-up Object Using In-situ Debris Measurement Satellite, The 73rd Intl Astronautical Congress, 2022.09, Collisions and explosions of satellites generate a large amount of sub-millimeter-size debris, which can cause fatal damage to a spacecraft. However, such tiny debris cannot be tracked from the ground. Therefore, an in-situ debris measurement satellite, which can detect impacts with sub-millimeter-size debris, has been proposed. Based on this concept, previous studies proposed the method to estimate some orbital parameters of the broken-up object. In those studies, it is assumed that the measurement satellite detects impacts at the intersection of the orbital planes of the measurement satellite and the broken-up object. However, simulated measurement data includes fragments contrary to this assumption. Thus, this study introduces a new approach to estimating the orbital parameters of the broken-up object from simulated measurement data. In this study, the inclination, the right ascension of the ascending node, and the nodal precession rate are estimated from the history of geocentric declination using the iteratively reweighted non- linear least square method.. |
| 43. | Kakeru Masaki, Yasuhiro Yoshimura, Hongru Chen, Toshiya Hanada, Dynamics of Spacecraft Attitude Considering High-Fidelity Solar Radiation Pressure, The 73rd Intl Astronautical Congress, 2022.09, Solar radiation pressure (SRP) is a major disturbance for a spacecraft operated in deep space missions, affecting its orbit and attitude, and high accuracy of the SRP calculation is required. The accuracy of SRP calculation is affected by the shape and surface characteristics of the satellite. However, existing computational models do not sufficiently take into account the exact reflective properties of the satellite surface. A detailed reflection model and considering the optical characteristics yield a different SRP and its torque from the conventional ones, resulting in a different attitude motion. In this study, an SRP calculation method that considers the exact reflective properties is applied to investigate the attitude dynamics.. |
| 44. | Kenta Nakajima, Yasuhiro Yoshimura, Hongru Chen, Toshiya Hanada, Stabilization of Space-advertisement Satellite Formation, The 73rd Intl Astronautical Congress, 2022.09, Space-advertisement is getting closer with advances in satellite formation flying, which displays an artificial constellation in the night sky. The formation shape composed of pixels of satellites equipping light sources is observed from the ground and is different from formation in relative orbits. For realizing the advertisement shape of high quality, there are two requirements, placing the pixels of the advertisement shape properly and keeping the shape during a visible span. It is not enough to satisfy the requirements of the usual coordinate systems and equations. Considering a topocentric coordinate system, the new transforming equations are derived so that an arbitrary advertisement shape is designed at the target time. Also, stable orbits that keep the formation shape without control are found and an example of stable orbits is presented.. |
| 45. | Koki Fujita, Yuya Ariyoshi, Yasuhiro Yoshimura, Yasunobu Ogawa, Toshiya Hanada, A Target Object Classification of Radar Observation Data with Constrained Admissible Region Analysis, The 33rd International Symposium on Space Technology and Science, 2022.03, This study proposes a method of classification prior to identification of space debris fragmented in a low earth orbit, which are detected through a ground-based observation. The proposed method is incorporated by a concept of Admissible Region, which can give a reasonable region of unknown two-dimensional parameters such as time-derivative of declination and right ascension for an observational direction. As the two unknown parameters are necessary to estimate orbital elements from observation data obtained through a radar system or a telescope, a method to find their existence region leads to effectively classify the radar observation data based on their orbital elements. The classification method derived in this study is finally verified using results of a correlation analysis between cataloged fragmentation debris and observation data obtained in a campaign at EISCAT Svalbard Radar in 2020.. |
| 46. | Kazunobu Takahashi, Yasuhiro Yoshimura, Hongru Chen, Toshiya Hanada, Analysis of Orbit Propagation Error, The 33rd International Symposium on Space Technology and Science, 2022.03, This study addresses and models the features of the global error accumulation generated though a numerical orbit prop- agation. To obtain fundamental findings and insights, the Cowell’s form, Runge-Kutta-Fehlberg (4, 5) method, and a variable step-size method are considered as the form of equation, numerical scheme, and stepping method, respectively. By measuring and observing the error generated, it is revealed that the error grows in proportion to the desired tolerance, squared calculation span, and squared mean motion. The influence of eccentricity is also investigated. The error accumulation model proposed here is valid for orbits whose eccentricity is less than 0.1 under the geopotential and third-body perturbations. Under the atmospheric drag and solar radiation pressure in association with the shadow of the Earth, the features of error accumulation cloud be more or less distorted. The findings and the model presented here enable evaluating the intrinsic error in the result from a numerical orbit propagation in a quantitative way.. |
| 47. | Ryusuke Harada, Satomi Kawamoto, Nobuaki Nagaoka, Toshiya Hanada, Environmental Impacts of GTO Objects on LEO, The 33rd International Symposium on Space Technology and Science, 2022.03, The effects of GTO debris to LEO environment are revealed using evolutionary model. GTO debris orbits are modeled as a reference of distribution of actual objects in GTO extracted from JAXA’s initial population file. Firstly, three cases of simulation with different perigee altitude were shown taking into accounts the distribution of GTO debris. It indicated that the debris with perigee altitude of over 400 km have long term effects while the debris with perigee altitude of 200 km decay shortly. The effect of continuously generation of GTO debris was secondly investigated. Since the GTO debris has long term orbital life, the number of its debris would keep increasing and accumulate in orbit. Lastly, the risk of GTO debris considering the actual number of debris and future works were discussed.. |
| 48. | Takahiro Maruyama, Hongru Chen, Yasuhiro Yoshimura, Satomi Kawamoto, Toshiya Hanada, Selection of Targets to Be Removed with Considering Timeliness, The 33rd International Symposium on Space Technology and Science, 2022.03, Because of the expansion of outer space activities, space debris is increasing considerably. To sustain the outer space activities, it is necessary to inhibit the generation and increase of space debris by active debris removal. By evaluating “timeliness”, this study determines the space debris to be removed which is a significant issue to improve the orbital environment efficiently. Then, the aims of this study are 1) proposing new evaluation indices considering dangerousness and timeliness and 2) discussing the effects of the indices on future environmental improvement. First, by focusing on the origins of space debris in the future orbital environment from the results of future projections, the necessary factors for the evaluation index are examined. Second, by applying the ridge regression model, the weighting of each factor is evaluated and then new evaluation indices are proposed. Finally, by discussing the future orbital environment following the removals of the objects selected by new evaluation indices, these indices have great effects for future environmental improvement.. |
| 49. | Aditya BARASKAR, Chen HONGRU, Yasuhiro YOSHIMURA, Shuji NAGASAKI, Toshiya HANADA, Shubham GOSAVI, Vivek BARASKAR, Energy Orbit–Laser Power Transmission to Satellites using Small Space Solar Power Satellite Constellation, 第７回宇宙太陽光発電（SSPS）シンポジウム, 2021.12, This paper illustrates and explains the benefits of Laser-based Wireless Power Transmission system models, including functional principles and mathematical formulation. Wireless power transfer is a possible solution to deliver continuous, convenient, and unlimited energy supply to satellites. Satellite industries traditionally use photovoltaic cells and nuclear generators to satisfy the demand for electricity required by spacecraft. Current power generation and management systems occupy a considerable portion of up to 10-25% of the satellite's mass. The concept of laser-based wireless power transmission from Space Solar Power Satellite can solve significant problems. The current design of Space Solar Power Satellite primarily focuses on creating a massive satellite to generate and transmit gigawatts of energy to an Earth-based ground receiving antenna. This idea can be adopted for spacecraft by developing a constellation of small-scale Space Solar Power Satellites or Energy Orbit to supply sufficient power to spacecraft within range. The theoretical and simulation modeling allows the analysis of power conversion or transmission for each individual unit in terms of the impacts of laser, transmission efficiency, and photovoltaic-cell thermal property. Maximum power transmission efficiency is calculated based on a linear approximation of power conversation between electricity-to-laser and laser-to-electricity validated by numerical simulation. This efficiency variation depends on the selection of Laser, transmitter, transmission distance, and photovoltaic cells, precisely increasing the maximum transmission efficiency of information in a wireless communication network. Consequently, this paper gives insight into wireless power transmission in general and adequate guidelines of the satellite to satellite power transmission system design in practice.. |
| 50. | 藤田浩輝，有吉雄哉，吉村康広，小川泰信，花田俊也, EISCATレーダー観測結果を用いた特定の破砕由来デブリ相関解析, 第65回宇宙科学技術連合講演会, 2021.11, This paper describes results of an analysis for certain groups of fragmentation debris in low earth orbit, which were detected via EISCAT radar during a campaign in 2020. In order to separate known or so-called the cataloged objects from the actually observed ones, a correlation analysis is conducted. Whereas some objects, especially the targeted space debris in the observation campaign are relatively well sorted, many other ones are not, which seem to be caused from specific effects from a typical radar observation. This paper also discusses about observed objects which were not correlated with the cataloged objects.. |
| 51. | 吹井柊太，吉村康広，花田俊也，陳泓儒, デュアルクォータニオンを用いた姿勢軌道計算, 第65回宇宙科学技術連合講演会, 2021.11, The number of objects in LEO region is increasing and the accurate tracking of all objects around the Earth is important. This paper studies the application of dual quaternions to attitude and orbit propagation. Dual quaternions are the extended concept of quaternions, which are widely used to describe attitude angles because of its singularity-free property. Since the set of dual quaternions forms a Lie group under the dual quaternion multiplication, Lie group geometric integration methods can be applied to integrate the state equation. This paper evaluates the accuracy of the calculation between a conventional Runge–Kutta method and the Crouch–Grossman (geometric integration) method. The results show that especially when larger time steps are considered, the Crouch–Grossman method outperforms the conventional Runge–Kutta method in terms of the structure preservation and the accuracy. This means that geometric integration schemes can be useful for propagation over a long period of time because larger time steps can be employed to reduce the computational time.cataloged objects.. |
| 52. | 蚊爪康吉，花田俊也, ステッパーに着目したスペースデブリの軌道伝播の改善, 第65回宇宙科学技術連合講演会, 2021.11, To counter the increasing threat of space debris in recent years, simulation tools for projecting the future population of space debris have been developed. It is indispensable for more accurate projection to improve the accuracy of orbit propagation. Therefore, this study compares methods (stepper) and step-size to solve a set of differential equations of motion to find out a better orbit propagation. . |
| 53. | 丸山貴大，陳泓儒，吉村康広，花田俊也, 緊急性を考慮したデブリ除去対象の選定, 第65回宇宙科学技術連合講演会, 2021.11, While the scale of outer space activities is expanding, space debris is also increasing considerably. To sustain outer space activities, it is necessary to prevent the increase of space debris by Active Debris Removal (ADR). One of the problems in ADR is to determine targets to be removed from the orbital environment. Previous studies have proposed several indices to evaluate whether debris must be removed or not, but different indices yield different results for removal targets. Therefore, further discussion is needed to establish an effective and reliable index. This paper proposes a new index that focuses on timeliness using space debris evolutionary model and regression models to obtain further improvement effects.over a long period of time because larger time steps can be employed to reduce the computational time.cataloged objects.. |
| 54. | 今村健司，吉村康広，陳泓儒，花田俊也, 自己遮蔽効果を考慮したライトカーブの可観測性解析, 第65回宇宙科学技術連合講演会, 2021.11, This paper conducts an observability analysis for attitude estimation of space debris with light curves considering self- shadowing. Light curves, which are time-varying apparent brightness of objects, are obtained as photometric observations for attitude estimation of space debris. The difficulty of the attitude estimation with light curves stems from sparse and limited observations. To improve the estimation accuracy, self-shadowing is incorporated with the observability analysis. As a preliminary study, this paper investigates the self-shadowing effect in the light curve observations and its observability changes are evaluated.. |
| 55. | 高橋雄文，陳泓儒，吉村康広，花田俊也, 地球影の再現性が軌道計算に与える影響, 第65回宇宙科学技術連合講演会, 2021.11, This paper addresses the degree of an impact of the fidelity of Earth shadows modeled on orbit propagation accuracy for spacecrafts orbiting Earth. When reproducing Earth shadows, there are two essential parts: the geometry and the solar ephemeris. Lots of them are introduced and utilized now for the orbit propagations. With demonstrating the gap of propagation results occurred due to the condition difference, this paper offers a clue of how to consider the fidelities of Earth shadow and solar radiation pressure properly so that propagation results satisfy desired accuracy.changes are evaluated.. |
| 56. | 松元駿，吉村康広，陳泓儒，花田俊也, 未知の推力加速度運動を行う宇宙機の相対軌道推定, 第65回宇宙科学技術連合講演会, 2021.11, With the expansion of the information infrastructure such as the launch of large constellation of satellites, the orbital environment is becoming more densely populated, and there is a need for the navigation focused on emergency from the viewpoint of Space Situational Awareness. This paper proposes a method for estimating the relative orbit of spacecraft with unknown thrust accelerations. In relative orbital motion, the target motion with unknown maneuver is estimated with optical observations (i.e., azimuth and elevation angles of non-resolved images). The proposed method estimates the thrust history of the target satellite by expressing it with a Fourier series expansion formula.changes are evaluated.. |
| 57. | 酒井大輔，吉村康広，陳泓儒，花田俊也，板谷優輝，福島忠徳, レーザアブレーションを用いた非協力衛星の姿勢安定化, 第65回宇宙科学技術連合講演会, 2021.11, This paper proposes an attitude stabilization method for a non-cooperative satellite using laser ablation. Due to the nature of laser ablation, the system has constraints in the direction of control torques. Such constraints disable generating desired torques in three-dimensional directions, and generated torques partially yield disturbances for attitude stabilization. The proposed method in this paper minimizes the undesirable disturbance torques, where the irradiation spot of laser is theoretically clarified. Numerical simulations are conducted to verify and discuss the effectiveness of the proposed method.. |
| 58. | Li Luo, Toshiya Hanada, Verification of Sub-millimeter-size Debris Removal Method Using Analytical Close Approach Analysis, 日本航空宇宙学会西部支部講演会(2021), 2021.11, This paper introduces a method of verifying the effect of a passive debris removal method focusing on the speed. While calculating the number of debris removed by the PDR satellite, the selected way is always ANCAS for its high precision. However, if the number of debris is vast, the time it takes will be too long. As a result, a solution to shortening the computation time is obtained efficiently using a series of prefilters that eliminate many cases from further consideration. This approach produces reliable results efficiently while dealing with the problem.. |
| 59. | Satomi Kawamoto, Nobuaki Nagaoka, Yasuhiro Kitagawa, Ryusuke Harada, Toshiya Hanada, Considerations on the lists of the top 50 debris removal targets, The 72nd Intl Astronautical Congress, 2021.10, Remediation measures, such as Active Debris Removal (ADR) has been studied in order to preserve the space environment. Large derelict objects in crowded orbits because they are the source of numerous small debris in case of fragmentation. The target for removal must be chosen carefully because cost is the major issue in realizing ADR, and it is necessary to remediate the orbital environment as efficiently as possible. Last year, Dr. McKnight et al. presented the top 50 debris removal targets by combining each of the top 50 lists compiled by eleven international teams. This paper discusses the considerations involved in selecting debris removal targets. The study first considered the top 50 objects in each index to be removed then evaluated the consequences of the removal using Near-Earth Orbit Debris Environment Evolutionary Model (NEODEEM), a debris evolutionary model developed by Kyushu University and JAXA. Differences in debris removal targets were studied for long-term stability or short-term safety. The paper discusses why some indices are effective in the short or long term in terms of the orbital distribution of selected targets and the effects of removal in each altitude band. The paper also discusses the differences between removing 50 objects and removing one object each year, and the effects of removal timing and so on. The study found that integrating different indices is effective, and that the removal target must be determined according to the situation. It is more important to remove as much debris as possible as early as possible rather than focusing on an object’s ranking in a list. . |
| 60. | Aditya Baraskar, Yasuhiro Yoshimura, Shuji Nagasaki, Toshiya Hanada, Wirelessly Powering Satellites Using Laser Emitter, Global Space Exploration Conference (GLEX 2021), 2021.06, This paper illustrates and explains the benefits of Laser-based Wireless Power Transmission system models, including functional principles and mathematical formulation. Wireless power transfer is a possible solution to deliver continuous, convenient, and unlimited energy supply to satellites. Satellite industries traditionally use photovoltaic cells and nuclear generators to satisfy the demand for electricity required by spacecraft. Current power generation and management systems occupy a considerable portion of up to 10-25% of the satellite's mass. The concept of laser-based wireless power transmission from Space Solar Power Satellite can solve significant problems. The current design of Space Solar Power Satellite primarily focuses on creating a massive satellite to generate and transmit gigawatts of energy to an Earth-based ground receiving antenna. This idea can be adopted for spacecraft by developing a constellation of small-scale Space Solar Power Satellites or Energy Orbit to supply sufficient power to spacecraft within range. The theoretical and simulation modeling allows the analysis of power conversion or transmission for each individual unit in terms of the impacts of laser, transmission efficiency, and photovoltaic-cell thermal property. Maximum power transmission efficiency is calculated based on a linear approximation of power conversation between electricity-to-laser and laser-to-electricity validated by numerical simulation. This efficiency variation depends on the selection of Laser, transmitter, transmission distance, and photovoltaic cells, precisely increasing the maximum transmission efficiency of information in a wireless communication network. Consequently, this paper gives insight into wireless power transmission in general and adequate guidelines of the satellite to satellite power transmission system design in practice.. |
| 61. | 丸山貴大，吉村康広，花田俊也，河本聡美, 九州大学における宇宙デブリのモデリング, 第９回スペースデブリワークショップ, 2021.02, The building of space debris evolutionary models makes it possible to discuss how to reduce space debris and improve future orbital environment. In order to have a better discussion, it is essential to improve the accuracy of estimation in space debris evolutionary models. In collision breakup models implemented in current space debris evolutionary models, it is somewhat unrealistic that the distribution of fragments generated during a collision depends on the primary object. Therefore, this paper proposes a method to determine which object generated each fragment and form the distribution of fragments not only around the primary object but also around the secondary object. This paper also compares future orbital environment before and after the improvement of collision breakup models and describes differences of future orbital environment by improved collision breakup models.. |
| 62. | 長岡信明，河本聡美，北川康弘，花田俊也, 推移モデルを用いた宇宙機の軌道投入許容量の検討, 第９回スペースデブリワークショップ, 2021.02, For the purpose of effective utilization of the orbital environment, the environmental capacity tolerance of insertions is studied using an orbital debris evolutionary model, developed in collaboration with Kyushu University. By inserting multiple spacecraft into a specific orbit regime and observing the impact on the orbital environment, the number of spacecraft that can be inserted into orbit (orbit insertion capacity tolerance) is evaluated. In this presentation, the results of studying the orbit insertion capacity tolerance due to differences in orbital regime, the number of inserted spacecraft, etc. Fig.1 demonstrates the difference in Effective Number of objects in LEO (Low Earth Orbit: altitude 200 to 2000 km) with and without 3000 spacecraft inserted into various orbital regimes. At altitudes below 800 km, natural decay due to the atmosphere may suppress the impact of insertions (and the generated debris). At altitudes between 800 and 1000 km, however, a remarkable increase in objects can be observed because of the many orbital residuals.. |
| 63. | 河本聡美, 長岡信明, 北川康弘, 柳沢俊史, 上野浩史, 中渡瀬竜二, 上田裕子, 八田真児, 花田俊也, JAXA 独自のデブリ推移予測用ベースラインファイルの 開発状況, 第９回スペースデブリワークショップ, 2021.02, A debris evolutionary model is indispensable for investigating effective debris mitigation measures and for developing international rules regarding space debris. JAXA has been evaluating the future space debris population using an evolutionary debris model named NEODEEM, developed in collaboration with Kyushu University. A baseline file is required for the debris Evolutionary model, which is the initial population data of the on-orbit environment, such as mass characteristics and orbits of all objects larger than 10 cm. JAXA has created its own baseline file by taking into account the area-mass-ratio evaluation from the TLE (Two Line Elements) history, literature review, and uncatalogued objects observed with the JAXA telescope, and so on. The baseline files provided by ESA at IADC have been used for research purposes only, but due to lack of information, for example, evaluation of specific debris removal targets was not possible. In this talk, the methods for developing the baseline file, the results of comparison with some debris models, and the results of debris evolutionary model predicted using the developed baseline files are reported. In particular, the evaluation of debris removal targets and the effectiveness of debris mitigation measures using the developed baseline files are introduced. In addition, the information that can be analyzed from the TLE history survey is introduced.. |
| 64. | 松下悠里, 板谷優輝, 吉村康広, 福島忠徳, 花田俊也, 低軌道 ADR ミッションにおけるターゲット物体の姿勢 運動解析, 第９回スペースデブリワークショップ, 2021.02, The orbital congestion is becoming an urgent issue with increasing space activities, such as satellite constellations for high-speed and large-capacity communications. Therefore, SKY Perfect JSAT Corporation has started out designing and developing an ADR satellite. The satellite applies laser ablation technologies so that it does not require any physical contact with a target object. ADR mission generally requires grasping the rotational motion of the target object in advance and reflecting it in its mission operations. The target object’s motion is usually complicated due to various disturbance torques acting on it. This presentation shows the short-term and long-term variation of attitude and angular velocities of the target object in Low Earth Orbit, considering the shift of the center of gravity.. |
| 65. | 中渡瀬竜二、八田真児、上田裕子、斉藤賢爾、花田俊也、 馬奈木俊介, 経済学からのデブリ問題分析, 第９回スペースデブリワークショップ, 2021.02, Space debris is an emerging global environmental problem. PMD of 90% and ADR of 5 to 10 every year is required for maintaining the status of LEO. Fulfillment rate of PMD is, however, still in unsatisfied level and its associated cost of ADR is unclear. This provides the challenge from both of technology and economics. Previous studies on economics of space debris are mostly analogy from environmental problems on the earth. Environmental economics, holding two Nobel Prize winners, can potentially provide key tool to understand this problem. In this study, we provide how environmental economics merits on understanding and solving debris problem including cost of PMD and ADR. Finally, we discuss requirements for economic scheme which are acceptable in international space scene.. |
| 66. | Yuri Matsushita, Ryohei Arakawa, Yasuhiro Yoshimura, Shuji Nagasaki, Toshiya Hanada, Attitude Estimation of Space Objects Using Glint, The 43rd COSPAR Scientific Assembly, 2021.01, Dynamic states such as shape, attitude, and surface properties are essential information to carry out active debris removal (ADR) and/or to check up operational states of satellites. A cost-effective measure is to inversely estimate dynamic states using light curves, a time history of light intensity reflected in surfaces of orbital objects. One of the difficulties of light curve inversion is that estimation accuracy is dependent on initial attitude angles and initial angular velocities, which comes from less information obtained by the observer compared to plural parameters to be estimated. Previous studies have determined initial states by using the image obtained by radar or adaptive optics. The problem is that previous studies require additional expensive equipment and do not take full advantage of cost-effectiveness of light curve inversion. This paper proposes a state estimation technique that can be completed only with light curves without using high-cost extra instruments by focusing on the rapid change of light intensity, called glint. Although high observability in the vicinity of glint is shown in previous studies, it is difficult to use glint as measurement data and estimation accuracy rather drops immediately after glint because of its high frequency. The proposed method in this paper is based on geometric constraints among the Sun, the observer and surfaces of orbital objects in glint detection. This paper formulates constraint conditions of glint mechanism, and also evaluates the accuracy of state estimation method using glint. Physically meaningless values that did not satisfy the geometric constraints in glint detection are presumed to be excluded from the estimation. Thus, numerical simulations verify that the proposed method can estimate the attitude of a space object with higher accuracy than conventional methods shown in previous studies. It is concluded, therefore, that the attitude estimation method using glint can realize an inexpensive and highly accurate attitude estimation that can be completed only with light curves.. |
| 67. | Kota Kondo, Yasuhiro Yoshimura, Shuji Nagasaki, Toshiya Hanada, Pulse Width Modulation Method Applied to Nonlinear Model Predictive Control on an Under-actuated Small Satellite, AIAA Scitech 2021 Forum, 2021.01, [URL], Among various satellite actuators, magnetic torquers have been widely equipped for stabilization and attitude control of small satellites. Although magnetorquers are generally used with other actuators, such as momentum wheels, this paper explores a control method where only a magnetic actuation is available. We applied a nonlinear optimal control method, Nonlinear Model Predictive Control (NMPC), to small satellites, employing the generalized minimal residual (GMRES) method, which generates continuous control inputs. Onboard magnetic actuation systems often find it challenging to produce smooth magnetic moments as a control input; hence, we employ Pulse Width Modulation (PWM) method, which discretizes a control input and reduces the burden on actuators. In our case, the PWM approach discretizes control torques generated by the NMPC scheme. This study's main contributions are investigating the NMPC and the GMRES method applied to small spacecraft and presenting the PWM control system’s feasibility.. |
| 68. | 藤田浩輝，矢野建，花田俊也, 複数の破砕由来デブリをターゲットとする地上観測計画効率化, 第２９回スペース・エンジニアリング・コンファレンス, 2020.12. |
| 69. | 長﨑秀司，丸山貴大，吉村康広，花田俊也, 低軌道大型デブリの能動的除去に向けた宇宙機のランデブー軌道設計に関する研究, 日本航空宇宙学会西部支部講演会（2020）, 2020.11, This study aims to design realistic multi-rendezvous trajectories for multiple removal spacecraft in low earth orbit. Genetic Algorithms is adopted to optimize the order of multi-rendezvous and the orbital parameters of the parking orbits, which minimize the velocity increment necessary for changing orbital planes between removal targets. Although single spacecraft may successfully rendezvous with selected targets within reasonable amounts of velocity increment and time, subsequent spacecraft need large velocity increment and time to complete the multi-rendezvous. Rendezvous trajectory design by utilizing not only incremental velocity but also nodal regression due to J2 perturbation in LEO obtains the reasonable solutions, however, it is necessary to optimize the whole, not partially to sustain the outer space activities.. |
| 70. | 田中紘生，花田俊也, 宇宙エレベーターは建設費が回収できるまで残存できるか？, 第６4回宇宙科学連合講演会, 2020.10, Space Elevator is a space transportation system for carrying payloads to outer space through tethers that connect between ground and outer space stations. Assumed that the construction cost of a space elevator can be recovered in 10 years, this paper evaluates the survivability of the space elevator after 10 years against space debris impacts. As a result, it is difficult to realize the space elevator without environmental remediation down to less than 10% of the present space debris population.. |
| 71. | 藤田 浩輝,有吉 雄哉,吉村 康広,小川 泰信,花田 俊也, EISCAT検出データからの複数の異なる破砕由来デブ リ同定手法, 第６4回宇宙科学連合講演会, 2020.10. |
| 72. | Aditya Baraskara, Yasuhiro Yoshimura, Shuji Nagasaki, Toshiya Hanada, Space Solar Power Satellite for Interplanetary Mission, The 71st Int'l Astronautical Congress, 2020.10, Ever since humans have landed on the moon, many space agencies have investigated the Moon, Mars, and asteroids, driven by the quest for knowledge and future space missions. For the interplanetary mission, space engineers are working on the satellite, conceptual design of space habitat, and exploration system. The state of the art in those missions relies on the radioisotope thermoelectric generator or solar panel attached with batteries to store power, which is plagued by certain limitations. For instance, the collection of solar energy is inversely proportional to the distance from the Sun. Moreover, to run the central processing unit, avionics and payload inside the spacecraft requires constant monitors of temperature. In addition, this power generation unit of satellites carries a pack of batteries to store energy, which makes more than 10 - 25 % of the weight of the satellites. In hindsight, space solar power satellite serves a potential for a more reliable source of energy transmission as compared to the traditional method. Space agencies have already studied space solar power station designing concepts for gigawatts wireless power transmission systems from space to Earth to fulfil global electricity demand. Yet another avenue where space solar power satellites support an application is its utility towards rovers and habitat. For instance, the rovers on the Moon and Mars moves very slow to maintain performance for a lifetime. On Mars, sandstorms affect the collection of energy at the attached solar panel to the rover. Furthermore, a difficult to investigate in the far side, crater, and polar region of the Moon, where sunlight is unavailable for a few days. This challenge can be suitably overcome by employing a space solar power satellite, which can be used for wireless power transmission, independent of its location. Such techniques demonstrate possible applications towards power transmission for unmanned aerial vehicles for faster mapping purposes. As such, the dependence of those aerial vehicles towards fixed energy storage becomes alleviated. In this paper, we are comparing power generation by traditional method vs space solar power satellite. Simultaneously the future habitat on Mars and the Moon will receive continuous power by developing a perfect small space solar power satellite system for interplanetary and solar-system investigation mission satellites to achieve continuous power.. |
| 73. | Tadanori Fukushima, Daisuke Hirata, Jun Yamada, Yuki Itaya, Takayo Ogawa, Katsuhiko Tsuno, Satoshi Wada, Toshikazu Ebisuzaki, Hiroshi Ueno, Takashi Hiramatsu, Akihiro Sasoh, Yusuke Nakamura, Toshiya Hanada, Yuri Matsushita, Removal of non-functional spacecraft by satellite-mounted laser, Laser Solutions for Space and the Earth 2020, held in conjunction with Optics and Photonics Intenational Congress 2020, 2020.04, SKY Perfect JSAT Co. has launched a new mission, which removes non-functional spacecraft by laser ablation from a satellite-mounted laser with keeping a safe distance, in order to achieve space sustainability in collaboration with RIKEN, JAXA, Nagoya Univ., and Kyushu Univ. Laser ablation takes advantage in control the attitude of tumbling objects. And recent progress of laser technology has increased the feasibility to mount such lasers on small satellite.. |
| 74. | Kota Kondo, Yasuhiro Yoshimura, Shuji Nagasaki, Toshiya Hanada, Pulse Width Modulation Method Applied to Nonlinear Model Predictive Control on an Under-actuated Small Satellite, AIAA Scitech 2020 Forum, 2020.01, [URL], This research proposes an innovative approach to detumble satellites’ triple-axis angular velocities with only one single-axis magnetic torquer. Since magnetic torque is generated perpendicularly to magnetorquers, no intended control torque along the magnetorquer can be produced, which makes systems underactuated. Our paper introduces a control method using Model Predictive Control (MPC) and compares it with B-dot control algorithm. By applying these control laws to Kyushu University Light Curve Inversion (Q-Li) Demonstration Satellite in numerical simulations, we describe the applicability of these control laws to underactuated systems.. |
| 75. | Yuri Matsushita, Ryohei Arakawa, Yasuhiro Yoshimura, Toshiya Hanada, Light Curve Analysis and Attitude Estimation of Space Objects Focusing on Glint, First Int'l. Orbital Debris Conf. (2019), 2019.12, Grasping of dynamic states of space objects such as shape, attitude, and surface properties plays a significant role in removing orbital debris and in monitoring the health of operational satellites. Light Curve Inversion is a cost- effective state estimation technique using light curves, a time history of magnitude obtained by ground-based observations. The problem of this method is, however, that the observer measure only scalar data regardless of plural parameters to be estimated so that estimation accuracy is dependent of the initial values of estimation procedure. This study proposes a high-accurate estimation method using only light curves focusing on their characteristic, especially the sudden change of magnitude, called “glint”. Constrained conditions governing glint detection are shown in this paper. They are essential to exclude meaningless values from initial value candidates by setting attitudes in glint detection as the initial state values. Moreover, they realize a high-accurate estimation regardless of the initial values by efficient update of states and covariance matrix with constrains in the estimation filter.. |
| 76. | Masaya Nitta, Yasuhiro Yoshimura, Toshiya Hanada, Space Debris Mitigation by Passive Debris Removal in Large Constellation, First Int'l. Orbital Debris Conf. (2019), 2019.12, Space business in recent years has reached a major turning point. One of the factors is that technological innovation has led to cost reduction and miniaturization of rockets and satellites, and the barrier to enter into space industry has been lowered. Constellation systems are attracting attention in recent years as new technologies. A constellation system is the system that achieves one mission using multiple satellites. Conventional satellite constellations have been used to deploy dozens of large satellites like GPS and Iridium, whereas recent satellite constellations for space broadband systems plan to launch 1000 or more small satellites at an altitude of 1000 km. Such a large-scale system is called a large constellation. There is a possibility that such a small satellite constellation will drastically change the way of space utilization. When a satellite breaks up, hundreds of thousands of space debris are generated (Fig.1). They continue to drift in space because there is not much natural purification effect around 1000 km altitude, and thus debris removal for the large constellation is necessary. Removal methods are categorized into two approaches; active debris removal and passive debris removal (PDR). Active debris removal is typically used for large debris, while passive debris removal is used for small debris (Fig.2). Even small debris need to be removed because they have enough energy to destroy satellites in operation. PDR satellites reduce kinetic energy by letting them penetrate debris and remove them by forcing them into the atmosphere by reducing the orbital radius of the debris. This study investigates the effectiveness of velocity decay of debris using PDR.. |
| 77. | Yasuhiro Yoshimura, Yuri Matsushita, Ryohei Arawaka, Toshiya Hanada, Combining Photometric Data Formulation with Attitude Model of a Spinning Solar Sail Spacecraft, First Int'l. Orbital Debris Conf. (2019), 2019.12, Photometric data obtained by ground-based observation provide much information of space objects such as their orbit, attitude, shape, and surface properties, which are useful sources for Space Situational Awareness (SSA). Such complicated and coupled information, however, makes state estimation with photometric data difficult, because expressing an object shape and its surface properties requires many parameters for each component. To tackle this problem, this paper formulates the object shape and its surface properties with a fewer number of parameters using spin averaging. Furthermore, they are explicitly related to the dynamics of the rotational motion considering solar radiation pressure. The proposed formulation can approximate light curves to be obtained, reducing the number of parameters for estimation. Numerical examples using the proposed approximation are provided to demonstrate the effectiveness of the proposed formulation.. |
| 78. | Daigo Izumizawa, Masahiro Furumoto, Yasuhiro Yoshimura, Toshiya Hanada, Generalized Collision Flux Approximation for In-Situ Measurements, First Int'l. Orbital Debris Conf. (2019), 2019.12, Debris with size less than 2 mm is called sub-millimeter debris. They have enough energy to cause fatal damage on a spacecraft, but cannot be tracked from the ground. Kyushu University has initiated the development of the in-situ measurement satellite to have a better understanding of the sub-millimeter-size debris environment. In order to investigate the natures of orbital planes on which debris may impact with the measurement satellite, the previous study has developed a collision flux model, to estimate the collision flux of debris into the measurement satellites, assuming both debris and measurement satellites are on circular orbits. This paper generalizes the previous assumption to be applicable to elliptical orbits. This paper proposes an environmental estimation model that estimates the distribution of sub-millimeter-size debris by using in-situ measurements by applying the nature to the algorithm of the particle filter. Finally, the proposed model using the particle filter is verified by numerical simulation using MASTER-2009.. |
| 79. | Satomi Kawamoto, Nobuaki Nagaoka, Tsuyoshi Sato, Toshiya Hanada, Impact on Collision Probability by Post Mission Disposal and Active Debris Removal, First Int'l. Orbital Debris Conf. (2019), 2019.12, The collision probabilities of debris objects with and without Post Mission Disposal (PMD) and Active Debris Removal (ADR) are evaluated and discussed. A debris evolutionary model named NEODEEM was jointly developed by Kyushu University and JAXA for use in predicting future debris populations and calculating collision probabilities. The collision probability in each altitude bin is initially compared with and without PMD or ADR. Then a case involving a large satellite constellation is also discussed. The effective number of debris objects at each altitude for the PMD success rates of the large constellation and the collision probability at each altitude are calculated. The collision probability per unit time will increase when a small satellite utilizes a drag augmentation sail or a tether as a PMD device, but the dwell time will be greatly reduced. A collision with a sail or tether will be non-catastrophic collision. Therefore, the use of such devices will reduce the cumulative collision probability and expected number of debris fragments.. |
| 80. | Toshiya Hanada, Towards Long-term Sustainability of Outer Space Activities, The Eleventh Kyushu Univ. – KAIST Symposium on Aerospace Engineering, 2019.12. |
| 81. | 田中紘生，花田俊也, 宇宙エレベーターの宇宙デブリに対する残存率評価, 日本航空宇宙学会西部支部講演会（2019）, 2019.11, The space elevator is a space transportation system to carry payload to outer space through a tether connecting between stations on the ground and in outer space. Its transportation cost is approximately one-tenth of the present transportation cost, so that it is possible to expect a substantial cost reduction. However, considering the collision of the space elevator with space debris, the survival probability of the space elevator after 10 years is nearly 0%. Therefore, this paper proposes a highly redundant system against space debris and an effective environmental remediation.. |
| 82. | 高橋雄文，吉村康広，長崎秀司，花田俊也, テザー衛星の挙動解析に対する距離関数の適用とその有効性, 日本航空宇宙学会西部支部講演会（2019）, 2019.11, Cleaning up space debris out there is recently needed for environmental remediation. Tether satellite system is one of those candidates. That satellite system is known that it has many prospects to achieve such missions. However, there are difficulties on analysis of the behavior of those tether satellite systems due to elastic behavior of tether. Because of that, the step-size when integrating the equations of motion is empirically set to a small constant value to stabilize the behavior. In that context, this research proposes a new analysis method which can set the step-size adaptively. In particular, we apply distance function to settle the problem.. |
| 83. | 丸山貴大，長崎秀司，花田俊也, 軌道環境推定に基づく能動的デブリ除去における プライオリティリストの評価, 日本航空宇宙学会西部支部講演会（2019）, 2019.11, Outer space activities are currently developing. At the same time, space debris are increasing considerably, so that Active Debris Removal (ADR) is necessary to prevent an increase in space debris that affect outer space activities. One of the problems in ADR is to determine targets to be removed from the environment. Priority Lists depending on various indexes have been proposed, but are too different to trust. This paper compares the resulting space environment based on various Priority List proposed herein to find out the right space debris index that can make the space environment better.. |
| 84. | 斜木悠里，藤田浩輝，花田俊也, 破砕由来デブリの軌道情報に基づく地上観測の効率化, 日本航空宇宙学会西部支部講演会（2019）, 2019.11, In order to detect and identify fragmentation space debris in low-earth orbit (LEO), observation experiments using EISCAT radar in the Scandinavian Peninsula have been conducted. This study aims to derive an efficient method for observation of unknown and known space debris originated from break-up events occurred to artificial satellites or spacecraft in LEO. Whereas the past study applied a stepwise method combining predicted orbital position distributions of cataloged space debris and a predictive observation simulation for them based on their Two-Line-Element (TLE) data and orbit propagation algorithms, this study takes an analytical approach using 2-dimensional histogram to the above predicted orbital position distributions considering their time change. The effectiveness of the derived method is also shown through comparing with results of a past observation campaign.. |
| 85. | 向麟，花田俊也, 光学観測による宇宙デブリの識別と運動軌跡検出, 日本航空宇宙学会西部支部講演会（2019）, 2019.11, Space debris has become a huge problem for outer space activity in the space. Observations are conducted around the world to detect and track space debris. One of the important problems in optical observation is how to get useful information from large amounts of image data to determine the orbit of space debris. In order to determine the orbit of space debris in the geostationary region, this paper proposes a new method to detect space debris and its trajectories from a series of images. Then, a Particle filter is applied to determine the orbit of space debris. This paper also verifies that the proposed method can successful determine the orbit of space debris.. |
| 86. | 古本政博，佐原宏典，花田俊也, 軌道上観測によるデブリ環境変動検知の統計的検証, 第６３回宇宙科学連合講演会, 2019.11, An impact of space debris smaller than 2 mm, which cannot be detected by ground-based observations can cause a fatal damage on a spacecraft. Therefore, in-situ measurements that detect small debris utilizing on-orbit impact sensors are promoted to monitor the environment of small debris. This paper proposes two statistical methods that detect environmental changes utilizing time-series impact data obtained by in-situ measurements. The first and the second methods focus on drastic and continuous changes of environment, respectively. This paper also demonstrates the statistical detection of environmental changes with numerical simulations. The simulations and discussions in this paper clarifiy correlations between area of impact sensor, mission duration and detectable scale of environmental changes. Outcomes of this paper can contribute to design in-situ measurement missions.. |
| 87. | 板谷優輝，福島忠徳，平田大輔，山田淳，吉村康広，出水澤大悟，松下悠里，花田俊也, 宇宙デブリ衝突による人工衛星ミッション終了リスクの定量化, 第６３回宇宙科学連合講演会, 2019.11, An impact of space debris smaller than 2 mm, which cannot be detected by ground-based observations can cause a fatal damage on a spacecraft. Therefore, in-situ measurements that detect small debris utilizing on-orbit impact sensors are promoted to monitor the environment of small debris. This paper proposes two statistical methods that detect environmental changes utilizing time-series impact data obtained by in-situ measurements. The first and the second methods focus on drastic and continuous changes of environment, respectively. This paper also demonstrates the statistical detection of environmental changes with numerical simulations. The simulations and discussions in this paper clarifiy correlations between area of impact sensor, mission duration and detectable scale of environmental changes. Outcomes of this paper can contribute to design in-situ measurement missions.. |
| 88. | 近藤耕太，吉村康広，坂東麻衣，長崎秀司，花田俊也, 一軸磁気トルカによる小型人工衛星の三軸デタンブリング制御, 第６３回宇宙科学連合講演会, 2019.11. |
| 89. | Satomi Kawamotoa, Nobuaki Nagaoka, Toshiya Hanada, Shuji Abe, Evaluation of Active Debris Removal Strategy Using a Debris Evolutionary Model, The 70th Int'l Astronautical Congress, 2019.10, Active Debris Removal (ADR) has been studied in order to preserve the space environment. Large debris objects such as defunct rocket upper stages and satellites in crowded regions are considered ADR targets, but it is important to identify which debris objects and how many debris objects should be removed. Future environmental changes have been evaluated by using a space debris evolutionary model that considers future launch traffic, explosions, collisions, and other factors. This study evaluates the effectiveness of ADR strategy by using the Near-Earth Orbital Debris Environment Evolutionary Model (NEODEEM) that was jointly developed by Kyushu University and JAXA. The effectiveness of ADR is evaluated by comparing such different ADR indexes as collision probability multiplied by mass, the expected number of fragments generated, and other indexes. Each index is shown to be effective for suppressing the increase of space debris, even though ranking orders differ for each index. The effects of limiting targets are also discussed, such as debris type (e.g., only rocket upper stages), mass, and orbit range, by showing the relations between limiting ADR targets and the required number of ADR objects to suppress the increase of space debris. For example, limiting ADR targets to rocket upper stages with mass of less than 4 tons is shown to increase the number of debris objects to be removed each year. Moreover, the removal of debris objects at lower altitudes is shown not to be effective, even though such objects have higher collision probabilities. The effect of disposal orbits where debris objects are to be moved is compared by changing the altitude of disposal orbits. The effectiveness of ADR for a large satellite constellation is also discussed. . |
| 90. | Kota Satoa, Makoto Hanada, Yasuhiro Yoshimura, Toshiya Hanada, Taku Izumiyama, Ryu Shinohara, The Optimal Collision Avoidance Maneuver with Multiple Objects in GEO, The 70th Int'l Astronautical Congress, 2019.10, This study aims to develop a new collision avoidance strategy for geostationary spacecraft. Recently, the continuous growth of space objects is increasing the collision risk among them. In the future, it will be necessary to operate the spacecraft while avoiding much space objects. However, there is a limit of fuel loading in a spacecraft, so it will be important to save fuel consuming each collision avoidance maneuvers not to shorten spacecraft lifetime rapidly. The proposed strategy considers the following points to save fuel and extend a spacecraft lifetime as much as possible. The first point is to avoid as many objects as possible at once maneuver so that the maximum collision probability is less than 1.0 × 10%&. The second point is to minimize fuel consumed by collision avoidance maneuvers and the next orbit maintenance maneuver. The last point is to maximize the period to keep a spacecraft in the station-keeping slot. To realize this strategy, multi-objective genetic algorithm optimizes maneuver time and maneuver vector. In the simulation, to simplify, a spacecraft avoids two approaching objects. The Spacecraft conducts collision avoidance maneuver as the East-West control maneuver and the North-South control maneuver, separately. As a result, in the case of once maneuver, collision avoidance is succeeded but the station-keeping period was too short, especially in the case of an East-West control maneuver. Therefore, it needs to conduct many maneuvers before the closest approach.. |
| 91. | Rhohei Arakawa, Yuri Matsushita, Yasuhiro Yoshimura, Toshiya Hanada, Attitude Estimation of Space Objects Using Imaging Observations and Deep Learning, The 20th Annual Advanced Maui Optical and Space Surveillance Technologies (AMOS) Conference, 2019.09, Optical measurements such as photometric observations and imaging observations have been widely applied for the estimation of the shape, surface properties, and attitude motion of space objects. Those informations enable us to improve the efficiency of active debris removal (ADR) and to investigate the health of the satellites. Although photometric observation is low-cost, previous study pointed out that initial values of attitude are necessary for high-precision estimation. Imaging observation by image matching method was examined to estimate those initial values in the previous study, considering that imaging observation is effective, especially for GEO objects. The purpose of this paper is to improve accuracy, robustness, and calculation cost of imaging observation applying machine learning, and to reveal the system requirement of imaging observation of GEO objects. The feasibility of imaging observation with existing optical system was verified, and by imaging simulation with different resolutions. Also comparing Convlutional Neural Network (CNNs) with estimation based on conventional image matching, it was clarified that the problems in the previous research were overcome.. |
| 92. | 花田俊也, A Handbook for Post-Mission Disposal of Satellites Less Than 100 kg, 2019年度UNISEC年次社員総会・活動報告会, 2019.07. |
| 93. | Masahiro FURUMOTO, Yasuhiro YOSHIMURA, and Toshiya HANADA, Improvement in an Estimation Method of the Debris Environment Utilizing In-situ Measurements, The 32nd International Symposium on Space Technology and Science, 2019.06, Space debris smaller than 2 mm that cannot be detected by ground-based observations may lead to a spacecraft's missions end. Therefore, multiple institutes and organizations have conducted in-situ measurement projects including the IDEA (In-situ Debris Environmental Awareness) project, which has been initiated at Kyushu University. The previous research has proposed a statistical method that estimates the environment of sub-millimeter-size debris sequentially utilizing in-situ measurements. This paper aims to improve accuracy of the estimation result by a “feedback estimation” method that utilizes the measurement data multiple times. Furthermore, this paper also calculates “total likelihood” to evaluate the accuracy of estimation results quantitatively so that effectiveness of the feedback estimation can be discussed. The evaluation with the total likelihoods suggests that the feedback estimation method can increase the accuracy of the environmental estimation. In conclusion, this paper contributes the improvement in the environmental estimation on sub-millimeter-size debris utilizing in-situ measurement. . |
| 94. | 斉藤賢爾，八田真児，花田俊也, 能動的デブリ除去のための，デジタル通貨を利用した経済プラットフォームの提案, 第８回スペースデブリワークショップ, 2018.12, We propose that the cost of ADR (Active Debris Removal) can be paid by circulating digital currency tokens whose values decrease over time. Such tokens are issued by global cooperation (a consortium) of parties interested in space development to parties who actually performed ADR, in exchange with proofs of removals. The tokens represent debts of the consortium, which is repaid through contributions by the token holders (as values of tokens decrease while holding them), who are likely to be benefited by removal of debris. This scheme imposes virtually no cost to the consortium. We have generalized this concept as PoD (Proof of Disposal), which, we believe, provides a more accountable foundation for solving social problems with digital currency than many ICO (Initial Coin Offering) in practice today.. |
| 95. | 長岡信明，河本聡美，花田俊也，阿部修司, 軌道上デブリ除去対象指標とその低減効果の比較, 第８回スペースデブリワークショップ, 2018.12, After the long space activities, large numbers of fragments generated by explosions and collisions of space objects are gradually increasing. In recent, many research organizations have reported that as a result of self-proliferation of these space debris without some mitigation process, future space activities will be affected. Also, in the private sector, mega constellation with thousands of satellites are also planned as a continuous communication infrastructure, and it should be necessary to consider the influence on the space environments. In this report, one guideline for improvement of future orbital environment after the result of space debris mitigation effect by some removal indexes for orbital objects with the propagation model of space debris created to predict the future debris distribution.. |
| 96. | 古本政博，出水澤大悟，吉村康弘，花田俊也, 軌道上観測データを用いた微小スペースデブリの環境推定, 第８回スペースデブリワークショップ, 2018.12, Space debris smaller than 2 mm cannot be tracked or detected by ground-based observations even though an impact of such small debris can cause a fatal damage on a spacecraft. Therefore, the environment of sub-millimeter-size debris must be monitored utilizing in-situ measurements. This paper proposes a statistical method to estimate the environment of sub-millimeter-size debris utilizing in-situ measurements. The proposed method consists of a sequential Monte Carlo filter and natures of orbits on which debris may be detected by the satellite. This paper also evaluates that the proposed method can sufficiently estimate the environment utilizing simulated impacts onto the satellite. Furthermore, this paper describes modifications to apply the proposed method to measurement data obtained by a satellite in an elliptic orbit.. |
| 97. | 花田俊也, 宇宙ごみのモデリングとその応用について, 第８回スペースデブリワークショップ, 2018.12, The orbital debris modeling can build evolutionary models as essential tools to predict the current or future orbital debris populations, and also to discuss what and how to do for orbital debris mitigation and environmental remediation. The orbital debris modeling can also devise an effective search strategy applicable for breakup fragments in the geostationary region using ground-based optical sensors, and to evaluate the effectiveness of space-based measurements of objects not tracked from the ground, both to contribute to space situational awareness. Another application of the orbital debris modeling is to estimate attitude motion of space objects to be removed for environmental remediation. This paper briefly introduces efforts into orbital debris modeling and applications.. |
| 98. | 荒川稜平，松下悠里，吉村康広，花田俊也, 光学観測による宇宙物体の動態推定に関する研究, 第８回スペースデブリワークショップ, 2018.12, Optical measurements such as photometric observations and imaging observations have been widely applied for estimating the shape, surface characteristics, and attitude motion of space objects. Photometric observation-based methods use light curves, the time history of the brightness of a space object, whereas imaging observation-based methods use images captured by the optical telescope and processed with adaptive optics. In Kyushu University, studies on the state estimation of space object with photometric observations have been conducted. In addition, an imaging observation-based method to determine an initial value for photometric observations and its feasibility have been studied. The current study describes a photometric observation-based method and verifies its accuracy by numerical simulations. Furthermore, a state estimation method that exploits both photometric observations and imaging observations is presented. The proposed method also shows the efficiency to apply image identification by convolutional neural network, a kind of machine learning, in imaging observations.. |
| 99. | 松下悠里，荒川稜平，吉村康広，花田俊也, ライトカーブインバージョン技術実証衛星 Q-Li, 第８回スペースデブリワークショップ, 2018.12, Kyushu University aims to establish a state estimation technique, called light curve inversion, which extracts dynamic states such as attitude motion and configuration from light curves. Light curves are brightness of space objects as a function of time and are obtained by ground-based observations. In order to demonstrate this technique, “Q-Li” the 3U Cubesat for Light Curve Inversion is being developed in Kyushu University. The primary mission of Q-Li is the on-orbit verification of the light curve inversion by comparing actual state and estimated one by light curve measurements. To this end, Q-Li deploys a membrane to reflect sunlight so that one can be observed from the ground. Q-Li measures her own attitude angles and angular rates in orbit and transmits them to the ground. As the secondary mission, Q-Li detects tiny debris collisions with the membrane by sensors located on its surface. In this workshop, not only the whole systems of Q-Li but also the deployment mechanism of the membrane and light curve inversion technique are presented.. |
| 100. | 出水澤大悟，古本政博，吉村康広， 花田俊也, 楕円軌道の衛星を用いた軌道上観測における 衝突フラックスの計算方法, 日本航空宇宙学会西部支部講演会（2018）, 2018.11, Space debris has been jeopardizing the lives of many spacecraft around the Earth since the beginning of the space age. Debris with a size less than 2 mm are called sub-millimeter-size debris.They have enough energy to cause a fatal damage on a spacecraft , but cannot be tracked from the ground.For that reason，Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness to have a better understanding of this yet unfamiliar sub-millimeter-size debris environment.In order to investigate the relationship between debris and measurement satellites，the previous study has developed a practical approximation method to calculate the collision flux of debris into measurement satellites，assuming that measurement satellites are on circular orbits.This paper proposes a new approximation method which can be applied to measurement satellites in elliptical orbits.. |
| 101. | 熊芳強，吉村康広， 花田俊也, 低軌道デブリの軌道上光学観測, 日本航空宇宙学会西部支部講演会（2018）, 2018.11, Space-based optical observation for space debris has excellent advantages compared to ground-based observation. This paper proposes a new concept to evaluate the coverage performance by a constellation of satellites in Sun-synchronous orbit in terms of the number of orbital planes based on several geometrical models and reasonable assumptions. According to the initial assumptions of the research, when the number of orbital planes is 6 or 7, we find that the constellation will lose the observable coverage of one satellite which circling one circle around the earth.. |
| 102. | 川野舞人， 花田俊也, 環境改善効果とミッション開始時期を考慮した現実的な複数個 能動的デブリ除去の軌道設計, 日本航空宇宙学会西部支部講演会（2018）, 2018.11, This study aims to design realistic multiple space debris removal mission for long-term environmental remediation. In the previous study, as mission criteria, velocity increment for successive orbit transfers and mission duration are optimized. This study examines the case of active debris removal with multiple satellites. Therefore, the multi-objective genetic algorithm with quasi-optimum solutions is adopted to derive optimal solutions.. |
| 103. | 藤田浩輝, 花田俊也, 吉川顕正, 山岡均, 柳沢俊史, 松本晴久, 神谷浩紀, 北澤幸人, Jussi Markkanen, 小川泰信, Constrained Admissible Region に基づく EISCAT 検出デブリ の軌道推定, 第62回宇宙科学連合講演会, 2018.10, This paper discusses a method to classify and estimate a distribution of the orbital elements for a cloud of debris fragments originated from a specific breakup event by utilizing data obtained from EISCAT radar observation. In the proposed method, by constraining admissible region of unobserved data set which are theoretically necessary to determine their orbits, the candidate objects as well as statistical distributions of their orbital elements are estimated from the original radar observation data. Finally, this study shows an effectiveness of the proposed method based on a real observation data.. |
| 104. | 古本政博， 吉村康広， 花田俊也, 軌道上観測による微小デブリ環境推定手法の構築, 第62回宇宙科学連合講演会, 2018.10, This paper proposes and evaluates a method that estimates the environment of sub-millimeter-size debris utilizing in-situ measurements. Space debris smaller than 2 mm are too small to be detected by ground-based observations, in spite of the dangerousness of sub-millimeter-size debris. Therefore, the environment of sub-millimeter-size debris should be estimated on the basis of the in-situ measurement data. This paper establishes an estimation method with a sequential Monte Carlo filter, which befits non-linear estimation problems. The estimation method consists of the natures of the orbits on which debris may be measured in-situ. This paper also evaluates the proposed method by simulations with an existing environmental model. The simulations demonstrate that the proposed method can sufficiently estimate the sub-millimeter-size debris utilizing the in-situ measurement data.. |
| 105. | 大渡慶太， 古本政博， 吉村康広， 花田俊也, ライトカーブインバージョン実証衛星“Q-Li”の開発, 第62回宇宙科学連合講演会, 2018.10, This paper describes a CubeSat named “Q-Li”, being developed at Kyushu University. The Q-Li intends to verify a light- curve inversion developed at Kyushu University for estimating the attitude motion of a spacecraft. The Q-Li deploys a sail with a high reflectance surface to make it easy to be observed from the ground, and records data of attitude motion using sensors to verify the light curve inversion. The verification can be conducted by comparing attitude motion between the light-curve inversion and the on-orbit measurement. This paper analyzes the mission of the Q-Li by simulating attitude motion and observed light curve. This paper also describes the design of the deployment sail. The design of the sail considers the reliability of deployment and the survivability against debris impacts.. |
| 106. | 吉村康広， 原田直輝， 小島広久， 花田俊也, 非対称物体の姿勢・質量特性推定, 第62回宇宙科学連合講演会, 2018.10, Relative attitude and inertial property estimation is an important phase in on-orbit servicing missions to provide information necessary for safe approach to a target object. Although the estimation usually uses optical devices, such observations may suffer from sudden change of the optical environment and intensive computational burden. To tackle these problems, this study shows an attitude and inertial property estimation method for an asymmetric target with low-rate observations. Using attitude angles periodically observed, the proposed method enables defining target states with constant parameters, which causes no error in state predictions of Kalman filter scheme even if the observation rate is low. Thus, the proposed estimation method is robust against the data deficiency and applicable with low-cost processors. Furthermore, the low-rate observations make the filtering easy to implement Iterated Extended Kalman Filter. Numerical examples verify the effectiveness of the proposed method and compare the results between Extended Kalman Filter and Iterated Extended Kalman Filter.. |
| 107. | 韓京達， 花田俊也, 吉村康広, テザー衛星の多質点モデルに関する運動解析, 第62回宇宙科学連合講演会, 2018.10. |
| 108. | 花田充， 泉山卓, 吉村康広， 花田俊也, 光学観測を用いた接近判定精度の向上, 第62回宇宙科学連合講演会, 2018.10, This paper proposes a method to reevaluate closest approach between space objects. The purpose of this study is to confirm the effectiveness of the proposed method and determine the observation requirements. This study allows operators who own spacecraft to reevaluate closest approach by a telescope. The reevaluation method consists of optical observation, orbit determination, and conjunction assessment. Numerical simulations are conducted under the assumption that a collision occur in a geostationary orbit. The result shows that it is necessary to observe for two nights for orbit determination and three nights for conjunction assessment.. |
| 109. | Masahiro Furumoto, Toshiya Hanada, Estimation of Orbital Environment Incorporating Environmental Change Due to Major Breakups Utilizing In-situ Measurements, The 69th Int'l Astronautical Congress, 2018.10, Even sub-millimeter-size debris could cause a fatal damage on a spacecraft. However, such tiny debris cannot be followed up or tracked from the ground. Therefore, Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness, which conducts in-situ measurement of sub-millimeter-size debris. One of the project’s objectives is to estimate the location of on-orbit satellite fragmentations from measurements. The previous study derived a constraint equation that applies for the orbital parameters of a broken-up object. The previous study also concluded that two or more measurement satellites are necessary to properly estimate a couple of orbital parameters of the broken-up object in certain special case. This study finds out that even a single measurement satellite can estimate the orbital parameters of the broken-up object. Furthermore, this study derives a new constraint equation that applies for the nodal regression rate of the broken-up object. Finally, this paper demonstrates an effective procedure for a single measurement satellite to estimate the location of on-orbit satellite fragmentations.. |
| 110. | Masahiro Furumoto, Toshiya Hanada, Environmental Estimation on Sub-millimeter-size Debris Utilizing In-situ Measurement Data, The 42d COSPAR Scientific Assembly, 2018.07, Space debris smaller than 2 mm, which cannot be tracked nor detected by ground-based observations, may cause a fatal damage on a spacecraft. To understand the environment of such sub-millimeter-size debris sufficiently, in-situ measurements and modeling should be conducted. Therefore, IDEA the project for In- situ Debris Environmental Awareness, which aims to detect sub- millimeter-size debris using a group of micro satellites, has been initiated at Kyushu University. To estimate the debris environment based on in-situ measurements from the project, this paper proposes an environmental model that estimates the population of sub-millimetersize debris utilizing the date, time and location at impact on a measurement satellite. The proposed environmental estimation is based on an algorithm of a particle filter, considering the natures of orbits on which debris can be detected by the in-situ measurement satellite. This paper also evaluates the proposed model with a simulation using MASTER-2009, which is the environmental model developed at European Space Agency. Comparison between the debris population predicted by MASTER-2009 and the simulated estimation verifies that the proposed model can estimate the debris environment. Collision flux estimated by the proposed model is also evaluated to predict the impact rate into the measurement satellite. It is concluded, therefore, that the estimation model proposed and evaluated in this paper can provide a better definition of sub-millimeter-size debris environment with in-situ measurements.. |
| 111. | Keita Owatashi, Mélissa Zemoura, Toshiya Hanada, Determination of Harmful Space Debris Using Two Collision Calculation Algorithms, The 42d COSPAR Scientific Assembly, 2018.07, This paper investigates which debris are highly dangerous to exacerbate the future orbital environment based on the outcomes of an orbital debris evolutionary model with two different algorithms of collision risk assessment. One is “Two- Sphere Overwrap” collision risk assessment, which focuses on the geometrical relation between the orbits of the two colliding objects, calculates the collision risk on the assumption that the objects are closest to each other at the intersections of the orbital planes at an interval of one year. The other is “Cube” collision risk assessment, which focuses on the relative positions of the two colliding objects, calculates the collision risk when both objects are inside a cube with a side of 10 km at an interval of 5 days. The previous study by the second author (Dr. Zemoura) identified harmful debris to be removed based on the outcome of an orbital debris evolutionary model with the “Two-Sphere Overwrap” collision risk assessment. As a result, it was found that there are removal debris with short-term environmental improvement effect and removal debris with long-term environmental improvement effect. This paper identifies harmful debris to be removed based on the outcome of the same orbital debris evolutionary model but with the “Cube” collision risk assessment. Finally, this paper compares harmful debris to be removed between the previous and present outcomes and investigate how the harmful debris to be removed change as the collision risk assessment changes.. |
| 112. | Charlie Bachtiar Gunawan, Kota Sato, Masahiro Furumoto, Yutaka Kodam, Toshiya Hanada, IDEA the Project for In-situ Debris Environmental Awareness, The Ninth Kyushu Univ. – KAIST Symposium on Aerospace Engineering, 2017.12. |
| 113. | Jingda Han, Toshiya Hanada, Applying Distance Function for Daynamics of Multi-point Masses Tether System, The Ninth Kyushu Univ. – KAIST Symposium on Aerospace Engineering, 2017.12. |
| 114. | 渡邉一史， 花田俊也， 藤田浩輝, 光学観測による宇宙物体の動態推定, 日本航空宇宙学会西部支部講演会（2017）, 2017.11, Defining a state of space objects by optical observation is major theme for many researchers. optical measurements of cosmic object enables us to obtain the information of attitude motion, surface characteristics and shape of the object which cannot be got by telemetry data. Using these information, we can contribute to grasp the health. Various methods exist for optical observation, but photometric observation and imaging observation are considered in this research. In this paper, we discuss the estimation of the attitude motion of a space object in the Geostationary region(GEO) using imaging observation. This analysis is based on simulations considering the performance of the AO system and the telescope and atmospheric fluctuation, and proposes the attitude determination method applying the method using computer vision. In the future, we aim at improving the accuracy of dynamic estimation by combining this method with photometric observation and clarifying the system requirements for actual observation.. |
| 115. | 藤田浩輝, 板谷優輝, 花田俊也, 吉川顕正, 山岡均, 柳沢俊史, 松本晴久, 神谷浩紀, Markkanen Jussi Sodankyla, 小川泰信, EISCATレーダー観測によるスペースデブリ同定, 第61回宇宙科学連合講演会, 2017.10, 欧州非干渉散乱(EISCAT)レーダーを用いたスペースデブリ観測の研究概要および2016年度に行われた予備実験で得られた観測データ解析の結果について述べる．本研究では，本来地球の超高層大気の組成・動態解析を目的としたEISCATレーダーを地球周回低軌道上におけるスペースデブリ観測に適用することを目的としている．ここでは，３年間の研究計画中，初年度に行われた低軌道上の人工物体検出および同定を目的とした予備実験の概要，観測結果，および観測データから検出された人工物体の解析結果について説明を行う．. |
| 116. | Kazufumi Watanabe, Toshiya Hanada, Koki Fujita, Dynamics Observation of Space Objects Using Adaptive Optics Simulation and Light Curve Analysis, The 18th Annual Advanced Maui Optical and Space Surveillance Technologies (AMOS) Conference, 2017.09, Defining a state of space objects by optical observation is major theme for many researchers. optical measurements of cosmic object enables us to obtain the information of attitude motion, surface characteristics and shape of the object which cannot be got by telemetry data. Using these information, we can contribute to grasp the health. Various methods exist for optical observation, but photometric observation and imaging observation are considered in this research. In this paper, we discuss the estimation of the attitude motion of a space object in the Geostationary region(GEO) using imaging observation. This analysis is based on simulations considering the performance of the AO system and the telescope and atmospheric fluctuation, and proposes the attitude determination method applying the method using computer vision. In the future, we aim at improving the accuracy of dynamic estimation by combining this method with photometric observation and clarifying the system requirements for actual observation.. |
| 117. | Yutaka Kodama, Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Estimation of Orbital Parameters of Broken-up Objects from In-situ Debris Measurement, The 68th Int'l Astronautical Congress, 2017.09, Even sub-millimeter-size debris could cause a fatal damage on a spacecraft. However, such tiny debris cannot be followed up or tracked from the ground. Therefore, Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness, which conducts in-situ measurement of sub-millimeter-size debris. One of the project’s objectives is to estimate the location of on-orbit satellite fragmentations from measurements. The previous study derived a constraint equation that applies for the orbital parameters of a broken-up object. The previous study also concluded that two or more measurement satellites are necessary to properly estimate a couple of orbital parameters of the broken-up object in certain special case. This study finds out that even a single measurement satellite can estimate the orbital parameters of the broken-up object. Furthermore, this study derives a new constraint equation that applies for the nodal regression rate of the broken-up object. Finally, this paper demonstrates an effective procedure for a single measurement satellite to estimate the location of on-orbit satellite fragmentations.. |
| 118. | Yuki Itaya, Koki Fujita, Toshiya Hanada, A Search Strategy Applicable for Breakup Fragments in Highly Elliptical Orbit, The 68th Int'l Astronautical Congress, 2017.09, This study aims to devise an effective search strategy for fragments in Highly Elliptical Orbit by developing a precise estimation scheme for the initial breakup states and by updating a population evaluating scheme of the previous studies. As for the estimation of the initial breakup state, a newly developed equation was introduced. This equation restricts initial distribution of orbital planes of fragments by using the parental object’s right ascension, inclination, right ascension of ascending node, and argument of perigee. The advantage of this constraint is that the fragments can be evaluated by using only two orbital elements which can guarantee relatively high propagation accuracy. A hybrid scheme combined with close approach analysis was proposed to estimate the initial breakup state including the breakup date and time. In the observation planning, this study utilized previous strategy aimed for breakups in Geostationary Orbit. This study upgraded the previous strategy by introducing separation angle between observation direction and direction of a fragment, so that high latitude areas are also evaluated properly. As a result, by using officially reported data, it was confirmed that the initial state estimation scheme for breakup can estimate the initial state precisely, and updated method can evaluate the population of fragments having high inclination.. |
| 119. | Yuki Itaya, Koki Fujita, Toshiya Hanada, Effective Search Strategy Applicable for Narrow Field-of-view Telescope, The 31st International Symposium on Space Technology and Science, 2017.06, This paper gives a thought of using narrow field-of-view telescopes to search fragments from breakups in the geostationary region. The previous studies had proposed an effective search strategy and validated it through observation campaigns. However, when this strategy was applied to a narrow field-of-view telescope, the detection rate was far less than expected. This problem was caused by the coordinate transformation. The previous strategy predicts the population as a function of geocentric right ascension and declination while telescopes need topocentric coordinates. Since each fragment at the observation point has its own geocentric distance, the actual detection rate decreases depending on the geocentric distance selected for the coordinate transformation. Especially, the error largely increases when using narrow field-of-view telescopes. Based on the above facts, this study aims to investigate the change of the detection rate caused by the coordinate transformation and to determine the most effective geocentric distance for the transformation. This study uses a result from the previous study targeting fragments from a US Titan 3C Transtage. Pegasus Observatory at Kyushu University, which has a narrow field-of-view of 0.5 deg, is selected for this study. The result indicates that the effects of coordinate transformation can be decreased when the proper geocentric distance is chosen.. |
| 120. | Yutaka Kodama, Koki Fujita, Toshiya Hanada, Estimation of Orbital Parameters of Broken-up Objects from In-situ Debris Measurements, The 31st International Symposium on Space Technology and Science, 2017.06, Even sub-millimeter-size debris still could cause a fatal damage on a spacecraft. However, such tiny debris cannot be followed up or tracked from the ground. Therefore, Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness, which conducts in-situ measurement of sub-millimeter-size debris. One of objectives is to estimate the location of on-orbit satellite fragmentations from measurements. The previous study derived a constraint equation that applies for the orbital parameters of a broken-up object. The previous study also concluded that two or more measurement satellites are necessary to properly estimate the orbital parameters of the broken-up object based on the constraint equation. This study finds out that even a single measurement satellite can estimate the orbital parameters of the broken-up object in some cases, however. Furthermore, this study derives a new constraint equation that applies for the nodal regression rate of the broken-up object. Finally, this paper demonstrates an effective procedure for a single measurement satellite to estimate the location of on-orbit satellite fragmentations.. |
| 121. | Masahiro Furumoto, Shin'ya Nakano, Koki Fujita, Toshiya Hanada, Estimation of Orbital Parameters of Broken-up Objects from In-situ Debris Measurements, The 31st International Symposium on Space Technology and Science, 2017.06, Orbital debris smaller than 1 mm in size still have enough energy to cause a fatal damage on a spacecraft, but such tiny debris cannot be followed or tracked from the ground. Therefore, Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness. This project aims to measure the sub-millimeter-size debris with a constellation of small satellites and to establish a dynamic environmental model to be updated continuously. A simple equation that constrains the orbital plane on which debris is detected through in-situ measurements has derived in the previous study by the authors. This study proposes an environmental model that estimates the population of sub-millimeter-size debris from in-situ measurement data with the constraint equation. This paper demonstrates and validates this estimation by impact simulations based upon MASTER-2009. The proposed model was validated that it could estimate the distribution of debris sufficiently. This paper also investigates characteristics of the proposed estimation, which suggest effective strategies to improve the environmental estimation.. |
| 122. | Satomi Kawamoto, Takayuki Hirai, Shiki Kitajima, Shuji Abe, Toshiya Hanada, Evaluation of Space Debris Mitigation Measures Using a Debris Evolutionary Model, The 31st International Symposium on Space Technology and Science, 2017.06, Debris mitigation measures such as post-mission disposal (PMD) were set by considering the effects thereof using a debris evolutionary model. Many small satellites have recently been deployed in orbit and various plans are proposed for a so-called mega-constellation consisting of thousands of satellites in Low Earth Orbit (LEO). New systems such as an electric propulsion system and air drag augmentation devices are also proposed for satellite de-orbit. Therefore, the impact of them must be discussed in order to preserve the space environment. This study evaluates the debris mitigation measures taken by using the Near-Earth Orbital Debris Environment Evolutionary Model (NEODEEM) that was jointly developed by Kyushu University and JAXA. It revealed that mega-constellations have much impacts on the debris environment, and that the future environment will be affected by the PMD compliance rate and how PMD is achieved.. |
| 123. | Keisuke Akari, Hiroshi Yamakawa, Toshiya Hanada, Koki Fujita, Development of an Orbital Model for Small-Sized Space Debris Considering Electromagnetic Fields around the Earth, The 31st International Symposium on Space Technology and Science, 2017.06, In this paper, effects of electromagnetic fields around the Earth on small space debris is studied. Since the space debris are charged by interacting with the ambient plasma, their motion can be affected by the electromagnetic environment of the Earth. For small space debris, the change in the orbit caused by the electromagnetic perturbing force can be remarkable. Therefore, electromagnetic perturbations on debris should be taken into consideration in order to precisely understand the orbital motion for small space debris. This study aims to construct an orbital model for small debris and offer qualitative understanding of perturbations derived from electromagnetic fields of the Earth.. |
| 124. | Koki Fujita, Ryusuke Harada, Toshiya Hanada, An Optimal Rendezvous with Multiple Space Debris Utilizing Nodal Regressions for Low Earth Orbits, The 31st International Symposium on Space Technology and Science, 2017.06, Aiming at applying to an Active Debris Removal (ADR) mission, this work proposes an optimal trajectory design to rendezvous with multiple debris utilizing different nodal regression rates between debris ’and removal satellite ’s orbits. Whereas there are some works treating optimal trajectories to remove multiple debris in LEO considering RAAN changes, this work focuses on spacecraft ’ s transfer orbit that can maximize the effect of the J2 perturbation. Considering that non-coplanar orbital planes for two debris cause relatively high velocity increment to transfer between them, a strategy utilizing different nodal regression rates caused by an orbital perturbation is derived, in which an approach of the RAANs for two debris’ orbits is expected only by waiting for a while. Despite of the effectiveness of the utilization of the orbital perturbation, it is often time-consuming to make use of nodal regressions the debris ’ orbits naturally have. Thus, this work utilizes an additional elliptical orbit, which cannot only be injected into from primary debris ’ orbit easily but also maximize the difference of nodal regression rates between the additional orbit and secondary debris ’orbit. An optimization technique called a Multi-Objective Genetic Algorithm is applied in order to simultaneously improve two different objectives: velocity increment and mission duration, and its effectiveness is finally demonstrated through a numerical experiments based on a priority list of environmentally critical space debris.. |
| 125. | Makoto Hanada, Koki Fujita, Toshiya Hanada, Hiroshi Yamakawa, Magnetic Field Effects on Sub-millimeter-size Debris, The 31st International Symposium on Space Technology and Science, 2017.06, This paper investigates effects of Lorentz force, induced by interference between geomagnetic filed and charged particles, on orbital evolution of charged particles to understand how Lorentz force changes population of sub-millimeter-size debris. This paper analyzes orbital evolutions of sub-millimeter-size fragments from Fengyun-1C deliberately fragmented in early 2007 in terms of orbital lifetime, position angle and angular separation. The difference of orbital lifetime due to Lorentz force is related with the change of the population in radial direction. Position angle and angular separation provide relative motions of charged particles with respect to uncharged ones in both directions of right ascension and declination. This study will be useful for modeling sub-millimeter-size debris.. |
| 126. | Masahiro Furumoto, Shin'ya Nakano, Koki Fujita, Toshiya Hanada, Environmental Estimation on Sub-millimeter-size Debris Using In-situ Measurement Data, The 7th European Conference on Space Debris, 2017.04, Space debris smaller than 1 mm in size still have enough energy to cause a fatal damage on a spacecraft, but such tiny debris cannot be followed or tracked from the ground. Therefore, Kyushu University has initiated IDEA the project for In-situ Debris Environmental Awareness. This project aims to measure the sub-millimeter-size debris with a constellation of small satellites. This study proposes a statistical model that estimates the population of sub-millimeter-size debris using in-situ measurement data. This paper demonstrates and validates this estimation by impact simulations based upon MASTER-2009. This paper also investigates characteristics of the proposed estimation, which suggest effective strategies to improve the environmental estimation. . |
| 127. | Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Environmental Estimation on Sub-millimeter-size Debris Using In-situ Measurement Data, The 27th AAS/AIAA Space Flight Mechanics Meeting, 2017.02, Space debris smaller than 1 mm in size still have enough energy to cause a fatal damage on a spacecraft, but such tiny debris cannot be followed or tracked from the ground. Therefore, IDEA the project for In-situ Debris Environmental Awareness, which aims to detect sub-millimeter-size debris using a group of micro satellites, has been initiated at Kyushu University. The IDEA project aims to construct the dynamic environmental model that provides a better defi-nition of the current orbital debris environment. This study proposes data as-similation method to estimate the environment of sub-millimeter-size debris us-ing in-situ measurement data. This paper also verifies the proposed model by simulating the measurement and the estimation. The simulation demonstrates that the estimation model can determine the orbital plane of the detected debris approximately.. |
| 128. | Osama Mostafa Abdelaziz ALI, Toshiya Hanada, Koki Fujita, Perturbation in Orbital Elements of a High Elliptical Orbit of Satellites Constellation, The 27th AAS/AIAA Space Flight Mechanics Meeting, 2017.02. |
| 129. | 古本政博，藤田浩輝，花田俊也，中野慎也, 微小デブリの軌道上観測による環境推定, 第13回宇宙環境シンポジウム, 2016.11. |
| 130. | 大渡慶太，花田俊也, 衝突フラックスによるスペースデブリの危険性評価, 日本航空宇宙学会西武支部講演会, 2016.11. |
| 131. | 花田俊也, スペースデブリ環境の理解に向けて, 第140回 地球電磁気・地球惑星圏学会 総会および講演会, 2016.11. |
| 132. | 北島 志樹, 阿部 修司, 花田 俊也, 河本 聡美, メガコンステレーションが軌道環境へ与える影響評価, 第7回スペースデブリワークショップ, 2016.10, For the sustainable human space development activities, space agencies have developed their own orbital debris environment evolutionary model, projected the debris environmental prediction considering various future scenarios, and studied better mitigation ways. Currently, some companies are developing space broadband network systems and planning to deploy hundreds or thousands of satellites into LEO, which might impose enormous impacts on the debris environment. The influences of such large constellations, called MEGA constellations, are necessary and urgent tasks to be evaluated. In Japan, JAXA and Kyushu University have jointly developed the evolutionary model “NEODEEM”. Present study assumes a large constellation with 1,000 small satellites and evaluates its impacts on the debris environment. The mechanisms of the environmental deteriorations are explained and then various scenarios are simulated and compared to each other.. |
| 133. | 榎本稔也, 渡邉 一史, 藤田 浩輝, 花田 俊也, 北澤 幸人, 光学観測による宇宙物体の動態推定, 第7回スペースデブリワークショップ, 2016.10, It is important to observe not only the shape and surface characteristic of space objects but also their change over time to correlate them and understand their origin and behavior. In case of objects in low Earth orbit, we cannot track always them. For example, we may lose an object while it is in Earth’s shadow, so that we may need to identify the lost object when it comes up again. Then, estimation of space object behavior using optical measurements is essential to identify it again. Therefore, it is necessary to figure out how space object behavior changes through measurements using medium- and small-aperture telescopes. Space object behavior in optical measurements have been studied for a long time. The imaging correction method using adaptive optics and the attitude and shape estimation method using photometric observation are picked up in this presentation.. |
| 134. | 阿部 修司, 花田 俊也, 吉川 顕正, 平井 隆之, 河本 聡美, 長期の宇宙活動に伴うスペースデブリ環境の推移予測, 第7回スペースデブリワークショップ, 2016.10, Space debris is the collection of defunct objects made by human being in space. One of the causes of space debris source/sink is space weather (for example, solar flare, solar energetic particle, geomagnetic storm) effect on space debris. To evaluate the effects of long term space weather activities on space debris environmental changes, this study conducts some simulations under different space weather activities using NEODEEM, a Near-Earth Orbital Debris Environment Evolutionary Model. F10.7 and Kp indexes are used as space weather related parameters. As a result, it is found that space debris environment would become significantly worse because of collision cascading even with no launches in the case of low solar activity, like as solar cycle 24. . |
| 135. | Toshiya Enomoto, Koki Fujita, Toshiya Hanada, Yukihito Kitazawa, Monitoring the Health of Geosynchronous Spacecraft Using Photometric Observations, The 67th Intl Astronautical Congress, 2016.09, In this paper, the health of geosynchronous spacecraft is monitored by using light curve observations. For example, whether or not solar paddles are properly deployed, and whether or not the antenna points toward the earth. In order to monitor the health status, an unscented Kalman filter (UKF) is used to estimate rotational states, such as quaternions and angular velocities. Also multiple-model adaptive estimation method is adopted for what?. Running several parallel UKFs, the MMAE method determines the most probable shape of the target spacecraft. Each filter has a different shape model, and the state is computed by the weighted sum of each filter’s estimate. The attitude and shape estimation method is shown in this paper. This study will be useful for checking up the operational states of three-axis stabilized geosynchronous spacecraft in a complex form. . |
| 136. | Shiki Kitajima, Koki Fujita, Toshiya Hanada, Designing Multiple Space Debris Removal Missions Considering Fuel Efficiency and Environmental Remediation, The 67th Intl Astronautical Congress, 2016.09, This study aims to design realistic multiple space debris removal missions from the perspective of fuel efficiency and environmental remediation. As mission criteria, velocity increment for successive orbit transfers, the expected number of fragments and mission duration are optimized. This study converts a multiple space debris collecting mission to a multi-objective combinational optimization problem. Therefore, the multi-objective genetic algorithm with random weighting methods is adopted to derive pareto optimal solutions. In order to achieve non-coplanar orbital transfer with a smaller velocity increment, the transfer strategy utilizing J2 perturbation via parking orbits is proposed.. |
| 137. | Shiki Kitajima, Shuji Abe, Toshiya Hanada, Satomi Kawamoto, Influences of Mega Constellations on the Orbital Environment, The 67th Intl Astronautical Congress, 2016.09, The influences of MEGA satellite constellation on the orbital environment are evaluated with the evolutionary model. Walker delta pattern constellation with 1000 satellites on the orbit of 1200 km altitude is assumed as a basic scenario. Various conditions are considered to study the mechanisms of the environmental changes. The constellation satellites can cause the congestion of space debris in two altitude ranges, lower orbit after disposal or initial higher orbit. Population increase in lower orbit affect to the environment for short span, and that in initial higher orbit has impact for long span.. |
| 138. | Masahiko Uetsuhara, Mitsunobu Okada, Yasunori Yamazaki, Toshiya Hanada, Sub-millimeter Size Debris Monitoring System with IDEA OSG 1, The 17th Advanced Maui Optical and Space Surveillance Technologies Conference, 2016.09, The 20-kg class microsatellite carrying debris impact sensors IDEA OSG 1 contributes to timely mapping and tracking capabilities for space debris in sub-millimeter size regime are essential to model the low earth orbit (LEO) environment and to improve spaceflight safety. IDEA OSG 1 will sample the sub-millimeter size debris environment in one of the most congested region in LEO by detecting impacts of sub-millimeter size debris and provide key data about the size, the time, and the location of impacted sub-millimeter size debris in near real time. . |
| 139. | 藤田 浩輝, 古本 政博, 花田 俊也, 観測衛星を用いた微小デブリ軌道面推定法の評価と改善, 第60回宇宙科学技術連合講演会, 2016.09, This paper describes an evaluation and improvement for a scheme to estimate orbital parameters of sub-millimeter-size debris cloud using impact data on measurement satellites. Sub-millimeter-size debris generated from a satellite fragmentation have a greater possibility to collide with measurement satellites on a line of intersection between the debris’ and measurement satellite’s orbital planes. If enough impact data from at least two measurement satellites in different orbits are given, a couple of debris’ orbital parameters, which define their orbital plane, can be efficiently identified. This work evaluates a performance of the proposed scheme based on data of near collision obtained from conjunction analyses, which consider a real break-up event and virtual measurement satellites in orbits. An improvement method of data screening is finally proposed and the effectiveness of the proposed method is demonstrated through error analyses for the measurement data from the numerical simulations.. |
| 140. | 花田 俊也, 阿部 修司, 吉川 顕正, 藤田 浩輝, スペースデブリ環境の理解に向けて, 第60回宇宙科学技術連合講演会, 2016.09, This paper briefly introduces efforts into space debris modeling towards a better understanding of space debris environment. Space debris modeling mainly consists of debris generation and orbit propagation. Debris generation can characterize and predict physical properties of fragments originating from explosions or collisions. Orbit propagation can characterize, track, and predict the behavior of individual or groups of space objects. Therefore, space debris modeling can build evolutionary models as essential tools to predict the stability of the current or future space debris populations. Space debris modeling is also useful and effective to improve the efficiency of measurements to be aware of the present environment.. |
| 141. | 阿部 修司, 花田 俊也, 吉川 顕正, 平井 隆之, 河本 聡美, 宇宙天気活動に伴うスペースデブリ環境の変動と予測, 第60回宇宙科学技術連合講演会, 2016.09, Space debris is the collection of defunct objects made by human being in space. One of the causes of space debris generation is space weather effect to space debris. In past time, many satellites were broken because of space weather effect, solar energetic particle, atmosphere drag, and so on. NEODEEM (Near-Earth Orbital Debris Environment Evolutionary Model) is the space debris evolutionary model developed by Kyushu University and JAXA. It helps us to evaluate how space weather activities contribute to the space debris environment changes. This paper performs some simulations under different space weather activities on NEODEEM. F10.7 solar flux is used as space weather related parameter. This paper also introduces the effects of space weather activities to long term space debris environment changes.. |
| 142. | Toshiya Hanada, Towards A Better Understanding of Space Debris Environment, Asian Joint Symposium on Aerospace Engineering 2016, 2016.05, This paper briefly introduces efforts into space debris modeling towards a better understanding of space debris environment.. |
| 143. | 花田 俊也, スペースデブリ問題の現状と世界動向, スペースデブリ脱軌道のための Laser Nudging 技術に関するシンポジウム（テクノ・シンポジウム名大）, 2016.02. |
| 144. | 松本晴久, 奥平修, 花田 俊也, 東出真澄, 九州工業大学, 仁田工美, 北澤幸人, 宇宙環境保全における微小デブリ研究の現状, 第１２回宇宙環境シンポジウム, 2015.12. |
| 145. | 花田 俊也, 藤田 浩輝, 古本政博, IDEA the Project for In-situ Debris Environmental Awareness, 第１２回宇宙環境シンポジウム, 2015.12, This paper briefly introduces IDEA the project for In-situ Debris Environmental Awareness, aiming a prompt and clear understanding of the current submillimeter-size debris environment in the low Earth orbit region. Orbital debris, even smaller than 1 mm, may cause a fatal damage on a spacecraft. Therefore, knowledge on submillimeter-size debris should be incorporated in design of spacecraft. However, the current submillimeter-size debris environment has not been defined well because measurements are quite limited in terms of orbital regimes and not continuously available yet. Thus, the IDEA project proposes to deploy a group of micro satellites, which conduct in-situ and near real-time measurements of submillimeter-size debris, into any orbital regimes to be monitored. This paper also introduces a simple constraint equation applicable for orbital planes on which debris contribute to the collision flux that a measurement satellite may experience. Finally, this paper reveals that two measurement satellites or more are necessary to properly estimate the orbital parameters of a broken-up object. . |
| 146. | 藤田 浩輝, 田﨑 洸彦, 古本 政博, 花田 俊也, ２基以上の観測衛星によるスペースデブリ軌道面推定手法の研究, 第５９回宇宙科学技術連合講演会, 2015.10, In this paper, a scheme to estimate orbital parameters of debris cloud using impact data on measurement satellites is proposed. Sub-millimeter-sized debris generated from a spacecraft’s breakup event have greater possibility to conflict measurement satellites on a line of intersection between two orbital planes. If enough impact data from at least two measurement satellites in different orbits are given, a couple of debris’ orbital parameters, which correspond to their orbital plane, can be efficiently identified. The effectiveness of the proposed scheme is finally validated through measurement data obtained from a numerical simulation of debris impacts between target debris and two measurement satellites.. |
| 147. | 花田 俊也, 吉川 顕正, 山岡 均, 野口 高明, 北澤 幸人, 柳沢 俊史, 松本 晴久, 汎地球観測ネットワークを基軸とした宇宙天気研究・教育の革新的国際展開, 第５９回宇宙科学技術連合講演会, 2015.10, Kyushu University established International Centre for Space Weather Science and Education shortly ICSWSE in April 2012. The ICSWSE is leading two major research areas: 1) magnetized environment of the Earth and 2) space debris environment. To contribute to the protection of space environment and space situational awareness the ICSWSE fuses these two major research areas into one new project through a technical and human network established under the MAGnetic Data Acquisition System / Circum pan Pacific Magnetometer Array (MAGDAS/CPMN) project at the ICSWSE. Now the ICSWSE is willing to establish a measurement network for space debris using small-aperture optical telescopes and a small satellite constellation being named DEBris Data Acquisition System / In-situ Debris Environmental Awareness (DEBDAS/IDEA). The telescopes are well organized to be robotically and remotely controlled including sophisticated image processing techniques and orbit estimation software. The satellites are conducting in-situ measurements of micron-size debris using an easy-to-operate new sensor developed at JAXA. Data acquired from the systems will be analyzed and modeled in a manner coupled with space weather science to provide a better understanding of the present and future space environment. The ICSWSE also aims at education for practical astronomy and space engineering at Kyushu University collaborative measurements in combination between robotic telescopes and small satellites space environmental awareness and space science including debris generation and resulting environment. origin identification. Practical astronomy provides you with planning and observation processing and detection and Space engineering provides you with small satellite design production and operation.. |
| 148. | 古本 政博, 藤田 浩輝, 花田 俊也, 超小型衛星による微小デブリモニタリング計画"IDEA"現状と今後の発展, 第５９回宇宙科学技術連合講演会, 2015.10, The “IDEA project” has been initiated at Kyushu University in 2011 to estimate the environment on sub-millimeter-sized debris that cannot be detected from ground-based observations. A piece of sub-millimeter-sized debris has large kinetic energy enough to cause fatal damage on a spacecraft, so that the environment of sub-millimeter-sized debris must be understood for safe and secure space development and utilization. For this purpose, the project aims to develop the small measurement satellites and construct the in-situ measurement network with satellite constellation. The feasibility study of the first satellite named “IDEA-1” has been conducted at Kyushu University, and now IDEA-1 is in the process of production at ASTROSCALE based on outcome of the feasibility study. This paper describes the outline of space debris issue, history of small satellite development at Kyushu University, IDEA project and IDEA-1. Post IDEA-1 is also considered at Kyushu University. IDEA-1 has two impact sensors to measure only the position of impact with a piece of debris. This paper also discusses what should be included in the post IDEA-1.. |
| 149. | Koki Fujita, Naoyuki Ichimura, Toshiya Hanada, Detecting GEO Debris via Cascading Numerical Evaluation for Lines in Image Sequence, The 16th Advanced Maui Optical and Space Surveillance Technologies Conference, 2015.09. |
| 150. | Ryusuke Harada, Koki Fujita, Toshiya Hanada, Optimization of Orbital Transfer of Electrodynamic Tether Satellite by Nonlinear Programming, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 151. | Hongru Chen, Yasuhiro Kawakatsu, Toshiya Hanada, Phasing Problem for Sun-Earth Halo Orbit to Lunar Swingby Transfers, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 152. | Toshiya Enomoto, Kenta Shiomi, Ryusuke Harada, Hideaki Hinagawa, Koki Fujita, Toshiya Hanada, Mission Feasibility of Sensing Attitude Motion of Rocket Body, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 153. | Yukihito Kitazawa, Haruhisa Matsumoto, Osamu Okudaira, Yugo Kimono, Toshiya Hanada, Faure Pauline, Yasuhiro Akahoshi, Mai Nakamura, Kozue Hashimoto, Akira Sakurai, Kunihiro Funakoshi, Tetsuo Yasaka, Development on In-Situ Measurement Sensors for Micro-Meteoroid and Small Space Debris at JAXA, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 154. | Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Dynamic Modeling on Micron-Size Orbital Debris, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 155. | Yuya Ariyoshi, Melissa Zemoura, Toshiya Hanada, Satomi Kawamoto, Effect of Small Satellites' Post-mission Disposal on Sustainable Space Utilization, The 7th International Conference on Recent Advances in Space Technologies, 2015.06, The number of small satellites as those that do not exceed 50kg is rapidly increasing in the low-Earth orbit region. Since the orbital debris mitigation guidelines released by United Nations, Inter-Agency Space Debris Coordination Committee and national space agency does not consider small satellites and typical large satellites separately, small satellites also should conduct post-mission disposal. However most small satellites are launched as piggyback satellites, affordable post-mission disposal of small satellites is different from that of typical large satellites, and this post-mission disposal of small satellites may cause the collisions to other satellites. For developers of small satellites, this paper introduces the effect of small satellites post-mission disposal on sustainable space utilization, which was presented by the authors in previous.. |
| 156. | Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Dynamic Modeling on Micron-size Orbital Debris Environment, Asian-Pacific Conference on Aerospace Technology and Science, 2015.05. |
| 157. | 星野 裕久, 花田 俊也, 日南川 英明, 小型光学系による低軌道物体の観測に関する研究, 第６回スペースデブリワークショップ, 2014.12. |
| 158. | 田川 真, 柳沢 俊史, 黒崎 裕久, 小田 寛, 花田 俊也, 軌跡を用いた軌道上物体検出手法の提案と適用結果, 第６回スペースデブリワークショップ, 2014.12. |
| 159. | ゼムラ メリッサ, 花田 俊也, 河本 聡美, 地球周回近領域の影響評価及びその起源イベントの識別, 第６回スペースデブリワークショップ, 2014.12. |
| 160. | 田川 真, 柳沢 俊史, 黒崎 裕久, 小田 寛, 花田 俊也, 地球天候モデルを用いた軌道物体観測計画立案, 第６回スペースデブリワークショップ, 2014.12. |
| 161. | 花田 俊也, 宇宙ごみのモデリングとその応用について, 第６回スペースデブリワークショップ, 2014.12, The orbital debris modeling can build evolutionary models as essential tools to predict the current or future orbital debris populations, and also to discuss what and how to do for orbital debris mitigation and environmental remediation. The orbital debris modeling can also devise an effective search strategy applicable for breakup fragments in the geostationary region using ground-based optical sensors, and to evaluate the effectiveness of space-based measurements of objects not tracked from the ground, both to contribute to space situational awareness. Another application of the orbital debris modeling is to estimate attitude motion of space objects to be removed for environmental remediation. This paper briefly introduces efforts into orbital debris modeling and applications.. |
| 162. | 花田 俊也, 吉川 顕正, 山岡 均, 北澤 幸人, 柳沢 俊史, 松本 晴久, 宇宙天気科学・教育との連携によるスペースデブリの光学と軌道上計測, 第１１回宇宙環境シンポジウム, 2014.12, Kyushu University established International Centre for Space Weather Science and Education, shortly ICSWSE, in April 2012. The ICSWSE is leading two major research areas: 1) magnetized environment of the Earth, and 2) space debris environment. To contribute to the protection of space environment and space situational awareness the ICSWSE fuses these two major research areas into one new project through a technical and human network established under the MAGnetic Data Acquisition System / Circum pan Pacific Magnetometer Array (MAGDAS/CPMN) project at the ICSWSE. Now, the ICSWSE is willing to establish a measurement network for space debris using small-aperture optical telescopes and a small satellite constellation, being named DEBris Data Acquisition System (DEBDAS). The telescopes are well organized to be robotically and remotely controlled, including sophisticated image processing techniques and orbit estimation software. The satellites are conducting in-situ measurements of micron-size debris using an easy-to-operate new sensor developed at JAXA. Data acquired from the systems will be analyzed and modeled in a manner coupled with space weather science to provide a better understanding of the present and future space debris environment. The ICSWSE also aims at education for practical astronomy and space engineering at Kyushu University, collaborative measurements in combination between robotic telescopes and small satellites, space environmental awareness and space science, including debris generation and resulting environment. Practical astronomy provides you with planning and observation, processing and detection, and origin identification. Space engineering provides you with small satellite design, production, and operation. . |
| 163. | 榎本 稔也, 塩見 健太, 原田 隆佑, 日南川 英明, 花田 俊也, 射出しない小型衛星によるロケット上段の 姿勢運動を把握するミッションの実現可能性, 日本航空宇宙学会西部支部講演会2014, 2014.11, This paper verifies the feasibility of sensing attitude motion of a rocket body remained in space by using a small satellite not released from the rocket body. satellite can bear up under the space. This paper analyzes the mission by assuming the H-2A upper stage and whether the Especially, the satellite is analyzed in the point of thermal and electrical balance.. |
| 164. | 藤原 智子, 鈴木 右文, 花田 俊也, 山岡 均, 総合的宇宙教育の実践 ―九州大学ペガススプロジェクトの取り組み―, 日本航空宇宙学会西部支部講演会2014, 2014.11, An educational program of astronomy and space engineering was established by cooperated academic staffs in various fields at Kyushu University since 2011, and related activities have been performed under the title of “Pegasus Project”. The purposes of this project lie in 1) providing interdisciplinary courses under the keyword “the Universe”, 2) practicing of management education using the system of the star guide qualification and contributing to the general public by outreach activities. The interdisciplinary education free from boundaries fixed between academic subjects yielded to broaden interest and to make students understand that academic subjects were linked closely with each other. It was also confirmed that it led students to have high motivation for learning and that it resulted maturing. Furthermore, outreach activities (i.e. visiting lectures and star parties) mainly carried out by qualified students as a star guide were expected not only to render services to the general public but also to promote sociability (ability of planning, presentation and communication) of students themselves. A developed course using a larger telescope is arrange for senior students. Through observations of transient objects (i.e. small solar system bodies and supernovae) or of artificial objects (i.e. satellites and space debris), they learn the technique of scientific and engineering approaches.. |
| 165. | 三船 陵子, 西見 和真, 山口 直宏, 清岡 美里, 藤田 浩輝, 花田 俊也, 低軌道人工天体の追尾観測と運動解析, 日本航空宇宙学会西部支部講演会2014, 2014.11, “Space environment observed by telescope” offered at Kyushu University is a practical course to learn astronomical observation and analytical methods for the observational results. In the course, one of the two groups aimed at observing artificial objects such as an artificial satellite and an abandoned rocket body in Earth’s orbit. In this paper, a tracking method to observe artificial objects in Low Earth Orbit (LEO) is described. Then, using image sequences captured on July 11 in 2014, results of an analysis to identify a target object, CZ-3 R/B are shown.. |
| 166. | 田川 真, 花田 俊也, 柳沢 俊史, 黒崎 裕久, 小田 寛, 暗い軌跡を用いた移動物体検出手法の提案, 第58回宇宙科学技術連合講演会, 2014.11, This paper proposes a new algorithm to detect apparently fast orbital objects by optical observations. The algorithm improves target object’s signal-to-noise-ratio against background by summing signals along expected streak direction. The signal-to-noise-ratio can be improved with proportional to square root of summed pixel number, theoretically. This algorithm is applied to actual observation datasets to confirm its feasibility. The application test results that the algorithm can detect an object appeared on images as streaks even if pixels’ intensity of each streak are weaker than background noise. It indicates that the algorithm can improve efficiency of geosynchronous object survey conducted by JAXA. The algorithm is applied to actual observation datasets to confirm its feasibility. The test results that the algorithm newly detects three detections correlated to two objects. It is also estimated that the darkest result of the three detections is composed of pixels with low signal intensity 0.66.. |
| 167. | 古本 政博, 田﨑 洸彦, 藤田 浩輝, 花田 俊也, 動的宇宙ごみ環境モデルの研究, 第58回宇宙科学技術連合講演会, 2014.11, This research intends to build a dynamic model on micron-size orbital debris environment that is updated every time small satellites send impact data to the ground. A piece of micron-size debris can cause fatal damage on a spacecraft because of its high impact velocity. However, measurement data of micron-size debris are quite limited because its size is too small to be observed from the ground. Therefore, we have initiated IDEA the project for in- situ debris environmental awareness to aim to construct an in-situ debris measurement network using a constellation of small satellites. This dynamic model can provide a better definition of the current orbital debris environment to contribute safe and secure space development. For optimization of the satellites constellation and dynamic modeling on micron-size debris environment, this paper investigates the detectability of debris in terms of orbital parameters and time.. |
| 168. | 元谷 臣吾, 花田 俊也, 中島 俊, Space Elevator 建造に関する対流圏ケーブル問題の解析, 第58回宇宙科学技術連合講演会, 2014.11, This paper present, method of calculating on original apply to search safety radius of the space elevator cable in the troposphere assuming strong window. The authors can’t write down the detail of experiment due to regulation of the quantity in this paper, but checked the Long column equation whether it was proper. The positive point on this method, can get analytically solution(but wind pressure distribution is idealized).Furthermore, able to clarify the stress properties in the time during reinforced cable, through the figure of analysis results. Then, can estimate an appropriate cable radius at initial cable[1.0mm respond to 1t (cruiser mass)], medium term[3.0mm respond to 10t ], and operative term[9.7mm respond to 30t ].. |
| 169. | Koki Fujita, Naoyuki Ichimura, Toshiya Hanada, Trajectory Detection of GEO Debris Utilizing Features of Image Motion, The 65th Intl Astronautical Congress, 2014.09, This paper proposes an efficient method to detect and track for debris in Geosynchronous Earth Orbit (GEO) using an image sequence and a voting scheme. The proposed method utilizes several motion features appearing in an image sequence which are obtained from a telescope fixed for the azimuth and elevation angles at a certain frame interval. Basically, linear trajectories of debris are detected using line segments which connect candidates of debris in different image frames. The line segments with image displacements over a limit value are removed using a couple of motion prediction techniques for GEO debris. The motion prediction techniques enable us to accelerate the voting scheme based on statistical features on motion direction and displacement computed from the line segments, and finally to detect trajectories of debris while removing ones of stars and noises. The effectiveness of the proposed method is demonstrated through observation image sequences acquired from the image sensor of the telescope called TAOS in Taiwan.. |
| 170. | Satoshi Furuta, Koki Fujita, Toshiya Hanada, Kazuki Takezono, Discussion on the Necessity of Orbital Debris Removal in the Geostationary Region, The 65th Intl Astronautical Congress, 2014.09, The geostationary region is a unique natural resource that is useful for mankind activities. If accidental collisions take place in the geostationary region, space communities would suffer great inconveniences. Therefore, it is necessary to assess collision risk in this particular region. Kyushu University has developed GEODEEM, an orbital debris evolutionary model, which simulates prolonged debris environment in the geostationary region. GEODEEM calculates the time-averaged probability of collision of a spacecraft with debris. This method cannot properly characterize debris periodically approaching operational spacecraft because the actual position of debris is not considered. Instead, this study adopts “Conjunction Analysis,” so that the relative distance between a spacecraft and debris is computed to evaluate the collision probability at the time of the closest approach. The purpose of this paper is to put forward the necessity of orbital debris removal in the geostationary region by presenting interesting results from “Conjunction Analysis”. Finally, this paper proposes a selection of debris to be removed.. |
| 171. | Yuki Seto, Toshiya Hanada, Yukihito Kitazawa, Survey and Origin Identification of Breakup Debris Using Time Delay Integration Method, The 65th Intl Astronautical Congress, 2014.09, Kyushu University has proposed a strategy applicable to optical search and origin identification of fragmentation debris generated by breakups of spacecraft and rocket bodies. This strategy can predict the population and the motion of fragments by using debris modelling techniques. An observation of fragments from a specific breakup was actually conducted by applying the proposed strategy. The target was the US Titan 3C Transtage (1968-081E) exploded in February 1992 in the Geosynchronous Earth Orbit region. In this observation, the Time Delay Integration method was adopted to detect fragments. This method can detect moving faint objects by adjusting a rate of charge transfer in the Charge Coupled Device sensor to their motion on images. In the case of the survey of unknown fragments, the predicted motion can be used as the charge transfer. As the result of this observation, thirty- one unknown objects were detected, and orbit determinations of seven objects have succeeded. The origins of these seven objects were estimated by comparing the estimated orbits with candidates, and one object was identified to the target object. Finally, this paper reviews the proposed search strategy by comparing with the twenty-eight catalogued 1968-081E fragments.. |
| 172. | Melissa Zemoura, Toshiya Hanada, Mitsunobu Okada, SECURING FUTURE EARTH-MOON COMMERCIAL SPACE TRAVELS: SIMULATION OF CAPTURE AND DE-ORBIT PHASES FOR ACTIVE DEBRIS REMOVAL IN NEAR-EARTH ORBITS , The 65th Intl Astronautical Congress, 2014.09, This study aims to secure future Earth-to-Moon commercial space travels starting from year 2045. After evaluating risky objects for the mission, the present study focuses on the next step: active debris removal in order to eliminate the related risks. The current proposal consists in launching a mother satellite into the identified objects’ orbital region that corresponds to 600km-800km-altitude range and 82o/98o inclination orbits according to previous results. The mother satellite has a simple cubic shape equipped with six devices (Boys). Each Boy is released from the satellite and attached to one target object. More precisely, this study focuses on the last step of the removal, by trying to analyze and optimize the final approach, the capture, and the de-orbit phases. To optimize the efficiency of the capture phase, the angular velocity, the attitude and the shape of the target have to be considered and evaluated for a better adequacy of the Boy with the object. After its release, the device hits the front side of the target, and according to the impact angle of the device on the target surface, the full adhesion of the boy to the object produces a force that modifies the attitude motion of the target object. To simulate the impact of this adhesive force, the Space Systems Dynamics Laboratory in Kyushu University has developed a complete propagator that associates an orbit propagator to an attitude motion simulator. Indeed, the attitude motion of an object is linked to its orbit motion, due to the mutual coupling effect of orbit perturbations and external torques that change the attitude. Therefore, this propagator allows performing a higher precision estimation for both orbit and attitude motions, which leads to first results concerning the configuration of the target after contact with the Boy. From this estimation, it is possible to evaluate the most adequate point of release for the Boy together with the best timing for the release. Then, de-orbit is operated by 9s-impulse burning from Boy’s thrusters to perform the descent of the target’s orbit. To stabilize this operation, this step is also simulated so as to characterize the impact of the thrust on the object’s motion and the shape of the descent orbit.. |
| 173. | Mitsuhiko Tasaki, Koki Fujita, Toshiya Hanada, IDENTIFYING ORIGIN OF BREAKUP EVENT BY IN-SITU MEASUREMENT, The 65th Intl Astronautical Congress, 2014.09, Kyushu University has initiated a project to understand the current micron-size debris environment by small satellites equipped with impact sensors. The objective of this study is to establish an estimation approach to identify an orbit on which a breakup event occurs using the measurement data from the satellites. This study assumes that two measurement satellites on different earth orbits get impacted with micron-size debris. In addition, this study is based on the presumption that the measurement satellite gets impact data at the line of node intersecting with the orbit of breakup object. This paper focuses on the Chinese anti-satellite missile test in 2007 and the US and Russian satellites accidental collision in 2009 to verify this estimation approach. In this study, a non-linear least squares method is used in order to estimate right ascension of the ascending node and inclination, which define an orbital plane. Using spherical trigonometry (a Napier’s rule), an equation to estimate unknown obital elements is derived. Results from this study confirm that the proposed in-situ measurements technique can identify the orbital plane on which the above breakup events occurred.. |
| 174. | Makoto Tagawa, Toshifumi Yanagisawa, Hirohisa Kurosaki, Hiroshi Oda, Toshiya Hanada, Follow-up Observatory for Low Earth Orbit Objects with a Detection Algorithm Using Streaks, The 15th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2014.09, Orbital object catalogue maintenance capability should be improved to correspond to future orbital environment because space objects population grows continuously. This paper proposes a follow-up observatory consists of uses of our new image-processing algorithm and the multi-telescope observation method. The algorithm enables to improve SNR of streaks by summing their signal intensities. The observatory applies the algorithm to recover SNR of objects unintentionally appeared as streaks in field of view. However, the improvement capability is limited to a square root of streak length as maximum, theoretically. The proposed observatory uses multi-telescope sets to recover rest of degraded SNR. The feasibility of the algorithm is confirmed by an application test to actual observation datasets. The test resulted that the algorithm enables to detect an object appeared with streaks darker than background noise, e.g. 0.66. This paper summarizes that the observatory can recover observation efficiency degradation due to unintentional appearance as streaks without on-site operation or complex instrument.. |
| 175. | Toshiya Hanada, Akimasa Yoshikawa, Yukihito Kitazawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Optical and In-situ Debris Measurements under Collaboration with Space Weather Science and Education, The 40th COSPAR Scientific Assembly, 2014.08, Kyushu University established International Centre for Space Weather Science and Educa- tion, shortly ICSWSE, in April 2012. The ICSWSE is leading two major research areas. One is magnetized environment of the Earth, and the other is space debris environment. Now, the ICSWSE fuses these two major research areas into one new project to contribute to the protection of space environment and space situational awareness. The ICSWSE has already established a technical and human network under the MAGnetic Data Acquisition System / Circum pan Pacific Magnetometer Array (MAGDAS/CPMN) project. Now, the ICSWSE is willing to establish a measurement network for space debris using small-aperture optical tele- scopes and small satellite constellation under the technical and human network, being named DEBris Data Acquisition System (DEBDAS). The telescopes are well organized to be robot- ically and remotely controlled, including sophisticated image processing techniques and orbit estimation software. The satellites are conducting in-situ measurements of micron-size debris using an easy-to-operate new sensor developed at JAXA. Data acquired from the systems will be analyzed and modeled in a manner coupled with space weather science to provide a better understanding of the present and future space debris environment. The ICSWSE also aims at education for practical astronomy and space engineering at Kyushu University, collaborative measurements in combination between robotic telescopes and small satellites, space environ- mental awareness and space science, including debris generation and resulting environment. Practical astronomy provides you with planning and observation, processing and detection, and origin identification. Space engineering provides you with small satellite design, produc- tion, and operation.. |
| 176. | Makoto Tagawa, Toshifumi Yanagisawa, Hirohisa Kurosaki, Hiroshi Oda, Toshiya Hanada, Detection Algorithm of Small and Fast Orbital Objects Using Faint Streaks; Application to Geosynchronous Orbital Objects, The 40th COSPAR Scientific Assembly, 2014.08, This paper proposes an algorithm to detect small or apparently fast orbital objects from optical images making use of their faint streaks. In the conventional algorithm, a high signal-to- background-noise-ratio (e.g., 3 or more) is required to detect objects. In our algorithm, we sum signals along the streak direction to improve sensitivity. By applying this algorithm to multi- images, we can detect lower signal-to-noise ratio objects. The algorithm consists of following steps; 1) take local sums of signal intensity on each pixel along preliminarily predicted streak direction, 2) find middle point candidates of streaks on each image, 3) search candidates of a sequence of points aligning in a straight line, and 4) select the candidate with the best linearity and reliability. In this paper, we focus on objects around geosynchronous orbit where most of streaks are oriented to South-North direction. We note that it is not reasonable to apply this algorithm to low Earth orbit objects having no specific streak direction because of limited computational resources. It requires orbit information from other facilities (e.g., space-based sensors). We confirmed that we can detect a streak appeared on images with approximately 1 signal-to-background-noise-ratio with applying the algorithm.. |
| 177. | Yuki Seto, Toshiya Hanada, Yukihito Kitazawa, Characterizing Breakup Fragments for Planning and Observations Using Time Delay Integration, The First Stardust Gloval Virtual Workshop (SGVW-1) on Asteroids and Space Debris, 2014.05. |
| 178. | Mitsuhiko Tasaki, Toshiya Hanada, Koki Fujita, Characterizing Environmental Change to Identify Its Origin by In-situ Measurements, The First Stardust Gloval Virtual Workshop (SGVW-1) on Asteroids and Space Debris, 2014.05. |
| 179. | Satoshi Furuta, Toshiya Hanada, Koki Fujita, Kazuki Takezono, Is Orbital Debris Removal Necessary in the Geostationary Region?, The First Stardust Gloval Virtual Workshop (SGVW-1) on Asteroids and Space Debris, 2014.05. |
| 180. | 花田 俊也, 宇宙ごみ環境のモデリングとその応用, 平成２５年度・第２回ＳＴＥ（太陽地球環境）現象報告会, 2014.03. |
| 181. | 花田 俊也, 世界トップのスペースデブリ環境評価技術の確立を目指して, 第１回データ同化応用研究会, 2014.02. |
| 182. | Hongru Chen, Yasuhiro Kawakatsu, Hanada Toshiya, Low-energy Escape from the Sun-Earth L2 Utilizing Unstable Manifolds and Lunar Gravity Assist, The 24th AAS/AIAA Space Flight Mechanics Meeting, 2014.01, The paper analyses escape trajectories utilizing lunar gravity assist and unstable manifolds of the Sun-Earth L2 point. There are 4 cases of crossing resulting from the intersection of the manifold tubes associated with the halo orbits and the orbit of the Moon. The 4 crossings have different V-infinity with respect to the Moon. The corresponding lunar gravity assists can result in a range of excess velocities with respect to the Earth. The results can be applied to the design of low-energy escape trajectories as well as the orbit control to bind spacecraft into the Earth system.. |
| 183. | Mitsuhiko Tasaki, Hanada Toshiya, Kazuaki Ae, Koki Fujita, The Observation of Micron-size Debris Environment by Using Multi-satellite Network for the IDEA Project, The 24th AAS/AIAA Space Flight Mechanics Meeting, 2014.01, Space System Dynamics Laboratory in Kyushu University has initiated IDEA, the project for In- situ Debris Environmental Awareness to correctly understand current space debris problem. One method selected by IDEA project is using multi-measurement satellites that have a dust impact detector. Latest mission analysis demonstrated that a constellation of measurement satellites is very fruitful to detect micron-size debris. As future action assignments, we are going to analyze how many micron-size debris collide against a dust impact detector on the IDEA satellites and study how we can identify the orbits of breakup objects by using the collision data.. |
| 184. | Masahiko Uetsuhara, Hanada Toshiya, Orbital Anomaly Analysis to Detect Breakups in GEO, The 24th AAS/AIAA Space Flight Mechanics Meeting, 2014.01, This study investigates abrupt orbital changes, i.e., orbital anomalies of the very old upper-stages Titan Transtages inserted into the geostationary orbit (GEO) region in 1960s and 1970s to find evidences of breakups. The product of the solar reflectivity (Cr) and the area-to-mass ratio (A/m) will be estimated before and after the orbital anomalies of the Transtages. To find evidences of breakups, characteristics of temporal distributions of CrA/m are compared between before and after the orbital anomalies. The known breakup of the Transtage 1968-081E will be utilized as the reference of the comparison study.. |
| 185. | Melissa Zemoura, Hanada Toshiya, Mitsunobu Okada, Near-Earth Orbit Debris Identification to Secure Future Earth-Moon Trajectory Mission, The 24th AAS/AIAA Space Flight Mechanics Meeting, 2014.01, This research aims to secure Earth-Moon travels for common people from 2045. Therefore, the capacity to predict the debris environment along this orbit is required. The idea is to identify the objects that may intersect the transfer orbit in 2045. Collision probability calculation gives the criterion to evaluate this degree of dangerousness in order to decide on the objects that must be removed. However, removal should be performed in advance, on the objects that generate the identified debris. Original debris removal baseline has been set as year 2020 to give enough time to conduct an effective debris remediation process.. |
| 186. | 花田 俊也, 北澤 幸人, 柳沢 俊史, 松本 晴久, 赤星 保浩, 宇宙デブリの現状と課題, レーザー学会創立40周年記念学術講演会・第34回年次大会, 2014.01. |
| 187. | 田﨑 洸彦, 藤田 浩輝, 阿江 和暁, 花田 俊也, 微小デブリ環境変動観測による破砕事象同定に関する研究, 日本航空宇宙学会西部支部講演会2013, 2013.11, Recently, space debris issues draw attention as what is impossible to overlook. However, we have only ground-based observation for space debris. Hence, this paper reveals the dynamics of environmental fluctuation caused by breakup events in order to identify them by using space-based measurements. The result was that maximum collision flux of space debris derived from breakup events is on the parent object’s orbit plane.. |
| 188. | 古田 諭史, 花田 俊也, 平山 寛, 静止衛星とその近傍にある非制御物体の衝突リスク評価, 日本航空宇宙学会西部支部講演会2013, 2013.11, The geostationary orbit is a unique natural resource that is useful for mankind activities. If accidental collisions occur in the geostationary region, space communities suffer great inconveniences. This paper estimates and evaluates the collision probability between a geostationary satellite controlled to stay at a specified longitude slot and its uncontrolled neighbors. Then this paper also investigates whether or not these uncontrolled neighbors should be removed.. |
| 189. | 瀬戸 裕基, 上津原 正彦, 花田 俊也, 北澤 幸人, 未知スペースデブリの起源同定に関する研究, 日本航空宇宙学会西部支部講演会2013, 2013.11, Kyushu University has established a method of origin identification of fragments from breakups in the geostationary region. This method can identify right origin of uncorrelated targets by comparing measured angular velocity and predicted angular velocity. Ground-based optical survey observations in February 2013, dedicated to possible 1967-066G fragments, have detected 87 uncorrelated targets and successfully followed up 3 uncorrelated targets. This paper explains the above method and the result of its application to these UCTs.. |
| 190. | 古本 政博, ジョン ミンソク, 日南川 英明, 花田 俊也, 超小型衛星を用いた宇宙ごみの速度ベクトル測定法の検討, 日本航空宇宙学会西部支部講演会2013, 2013.11, This paper investigates a possibility for a micro satellite to measure the impact velocity of micron-size debris not being tracked from the ground. This paper also establishes a method to determine the orbit of the debris impacted, and evaluates the effect of error in measurement of the velocity on error in orbit determination.. |
| 191. | 松本 晴久, 花田 俊也, 北澤 幸人, 奥平 修, ELMOS衛星によるメテオロイドとデブリのその場観測, 第57回宇宙科学技術連合講演会, 2013.10, The JAXA has been evaluating the risk of the micro-debris impact with spacecraft with regard to ADEOS-II (Midori-II) satellite anomalies. The results showed the damage on the wire harness and other equipment even when the impact of the micro-debris was due to particles in the range of 100um to several millimeters. It is difficult to obtain data on the environment space in required to evaluate the frequency of impact on a satellite by micro-debris, and currently, we are unable to get real-time data. Under these circumstances, it is urgent that environmental data be measured to understand the effect of impact by micro-debris on the safe operation of a satellite and the accurate evaluation of the frequency of these impacts. This paper reports a new-type active dust sensor and a In-situ Observation of Micrometeoroid and Orbital Debris by ELMOS satellite.. |
| 192. | 田川 真, 花田 俊也, 柳沢 俊史, 松本 晴久, 北澤 幸人, 軌道上光学システムを用いた地球低軌道小径デブリ追跡, 第57回宇宙科学技術連合講演会, 2013.10, The Earth orbital environment has been fouled by debris for decades and it is a threat for safe and sustainable space development and its utilization. There are two major countermeasures for this threat; one is protection and the other is collision avoidance. However, current collision avoidance maneuvers may be applicable only for objects larger than 10 cm and it is ten times larger than present maximum of protectable size. This study proposes a collaborative observation between space-based sensors and ground observatories. According to an initial analysis, approximately 10% of small objects in the Low Earth Orbit can be discovered by a single space-based sensor in four years. And it is found that an orbit initially determined by the single space-based sensor has enough accuracy to detect object smaller than 5 cm by ground observatories with assumed specifications.. |
| 193. | 花田 俊也, 吉川 顕正, 柳沢 俊史, 松本 晴久, 北澤 幸人, 宇宙活動の長期的持続性のためのアジア・太平洋地域の連携, 第57回宇宙科学技術連合講演会, 2013.10, This paper proposes Asia-Pacific regional collaboration for long-term sustainability of outer space activities. This regional collaboration aims to establish an orbital debris measurements network using ground-based optical and small aperture telescopes to be deployed in Asia-Pacific region and a group of small satellites detecting micron-sized debris. This measurements network aims at a prompt and clear understanding of the current orbital debris environment. This regional collaboration also offers capacity building in the area of space environmental science and engineering for students and young researches in Asia-Pacific region. Both activities will be cooperated with International Centre for Space Weather Science and Education of Kyushu University.the case with post-mission disposals and the case without post-mission disposals.. |
| 194. | 有吉 雄哉, 花田 俊也, 河本 聡美, 小型衛星の宇宙環境保全への影響, 第57回宇宙科学技術連合講演会, 2013.10, Developers of small satellites may think of enlarging their effective cross-sectional area to minimize the long-term presence in the low Earth orbit region. However, the enlargement of their effective cross-sectional area causes the temporal increase of cumulative probability of accidental collisions. This paper evaluates the influence of small satellites ppost-mission disposal by enlarging their cross-sectional area on the future population using an orbital debris environment evolutionary model. According to the result of the future projections, the small satellites ppost-mission disposals by enlarging the effective cross-sectional area have the potential risk of increasing the accidental collision. However in the case that small satellites are inserted into orbit below 800 km, the fragments to be generated by collision expected to decay within short term. The effective number of objects below 2,000 km altitude is not different between the case with post-mission disposals and the case without post-mission disposals.. |
| 195. | Makoto Tagawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Hirohisa Kurosaki, Hiroshi Oda, Yukihito Kitazawa, Toshiya Hanada, Image Stacking Method Application for Low Earth Orbit Faint Objects, The 14th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2013.09, The Earth orbit has been contaminated by artificial objects for decades. Therefore, Space Situational Awareness (SSA) is one of the most important actions for safe and sustainable space development and its utilizations. Orbital objects tracking and maintaining their catalog is the fundament of the activities. To improve the effectiveness of SSA activities, objects tracking capability should be enhanced in terms of applicable size limitation. This paper proposes a collaborative observation method consists of space-based sensors and ground observatories. The proposed method aims to discover and track faint objects in Low Earth Orbit (LEO) by ground observatories using initial orbit estimation result provided by space-based sensors. This follow-up observation is based on an assumption that signal amplification using the image stacking method developed by Japan Aerospace Exploration Agency (JAXA) can be applied to faint LEO objects. However, the applicability of this method is confirmed only for objects in geostationary orbit. Therefore this paper assesses the feasibility of faint LEO object detection using the image stacking method. This paper concluded that the image stacking method based on the space-based observation is applicable for ground observations of LEO objects. And it is also concluded that the proposed ground observatories are able to observe objects smaller than 1 – 5 cm by single 1 m telescope with the image stacking method.. |
| 196. | Hiroaki Hamada, Toshiya Hanada, Using a Small Satellite to Verify the Wireless Power Transmission in Space, The 29th International Symposium on Space Technology and Science, 2013.06, Wireless power transmission is useful in the environment where has difficulty to build electrical equipment. Currently, ground use is enthusiastic; however, space use has wide possibilities, but visualizing utilization is still developing. For future use of wireless power transmission in space, this research tries to clarify the possibility for the necessary equipment verification environment by small satellite. This research takes four steps. First step designs the verification satellite that satisfies the requirement for size, structural strength, mission and operational component, and satellite operation. Second considers the possible experiment contents used by the designed satellite. Third clarifies the requirements according to the contents of experiments. Final step identifies the feasibility of the verification satellite by comparison with demanded requirements and acceptable requirements for verification satellite. This paper mainly indicates about the first step of research. Paper describes the prototype design of verification satellite and experiment contents that can be achieved by the satellite.. |
| 197. | Matsumoto, H., Kitazawa, Y., Okudaira, O., Toshiya Hanada, Sakurai, A., Funakoshi, K., Yasaka, T., Akahoshi, Y., Hasegawa, S., Space Debris Sensor for In-situ Observation of Micrometeoroid and Orbital Debris in JAXA, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 198. | Hongru Chen, Huixin Liu, Toshiya Hanada, Storm-time Atmospheric Density Model Using Neural Networks and the Application in Orbital Decay Prediction, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 199. | Makoto Tagawa, Toshifumi Yanagisawa, Toshiya Hanada, Haruhisa Matsumoto, Yukihito Kitazawa, Correlation Capability of Space-based Optical Observation for Low Earth Orbit Objects, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 200. | Kazuaki Ae, Toshiya Hanada, Towards Micron-size Debris Modeling Based on In-situ Measurements Data From IDEA, The 29th International Symposium on Space Technology and Science, 2013.06, The purpose of this research is to estimate as-yet-unknown environment of tiny debris between 100 μm and 1 mm . Because of its high velocity, even though micron size debris, it is quite possible to cause critical damage on spacecraft. It might be a major obstacle to future development of space technology. Therefore, for the safe and secure space developments, ever-growing the importance of provision about micron size debris. However, micron size debris cannot be observed from grand-based sensors because it is too small. Thus, measurement data are very limited. We have to construct a novel measurement system for micron size debris. This paper introduce IDEA the project for In-situ Debris Environmental Awareness that aims to construct an in-situ measurement network using a group of nano satellites and the usage of actual measurement data acquired from IDEA-1 satellite.. |
| 201. | Changzhi Dong, Toshiya Hanada, IDEA Structure Optimized for Launch and In-situ Debris Measurements, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 202. | Hideaki Hinagawa, Toshiya Hanada, Development of Attitude and Orbital Motion Simulator for Small Satellite, The 29th International Symposium on Space Technology and Science, 2013.06, This paper describes development of a satellite simulator with precise dynamics model including a coupled orbit and attitude motion. In addition, this paper demonstrates orbit determination, attitude determination, and attitude control system from sun sensors model, magnetic sensor model, and gyro model. For attitude controller, magnetic torquers model are installed, and demonstrate two attitude control modes. This simulator will be useful to s small satellite development in Kyushu University, and it is supposed to be used for other application such as ground-based optical observation, and light curve modeling. As an optional support for users, this simulator can visualize its motion using OpenGL.. |
| 203. | Hiroshi Hirayama, Hitoshi Yamaoka, Tomoko Fujiwara, YUBUN SUZUKI, Toshiya Hanada, Space Education for Senior Students Using the Pegasus Telescope of Kyushu University, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 204. | Hideaki Hinagawa, Toshiya Hanada, Various Comparisons on Light Curve’s Amplitude and Visible Area of H2-A Rocket Body, The 29th International Symposium on Space Technology and Science, 2013.06, Light curves observation attracts the attention of researchers to investigate and estimate spacecraft’ attitude motion from the measurement because the spacecraft they concern is most likely orbital debris that should be removed for better space environment. This estimation technique is often derived from asteroid’s research. This technique might come into some problems when the technique is applied to objects in low earth orbit because the spacecraft is exposed to different perturbation and disturbance forces that differ from asteroids. Therefore, it is important to model the orbit and the attitude motion very precisely to obtain good estimation. This paper presents that how the light curves change with different perturbations and disturbance forces about a rocket body that is a major target for active debris removal. . |
| 205. | Shingo Ikemura, Hideaki Hinagawa, Toshiya Hanada, Model for Light Curves of Massive Body, The 29th International Symposium on Space Technology and Science, 2013.06, For safe and sustainable space activities, orbital debris environment must be remediated. When active debris removal (ADR) is considered, the target’s attitude motion should be known for a succession of the removal mission. This is because of a way to remove debris by targeting them and exerting some sort of forces on the targets actively. The information on target’s attitude can be estimated from light curves. Indeed, there is a way to observe the attitude directly, but it costs much. As for the way to estimate it from light curves, it cost much less than the former way. However, before working on the estimation, dynamics of the target motion should be revealed as well as how the light curves corresponding to it can be observed. On the other hand, suitable targets of ADR are massive objects since the number of the targets that can be removed during single ADR mission. Thus, this study models the massive object’s motion and the light curves. This paper describes the modeling results and discussions. . |
| 206. | Masahiko Uetsuhara, Toshiya Hanada, An Iterative Search Strategy for Characterizing Spacecraft Breakup Events, The 29th International Symposium on Space Technology and Science, 2013.06, This paper proposes a method to effectively estimate scales of breakup events in the geostationary region. The proposed method is based on the orbital debris modeling techniques, which describes generation and orbit propagation of debris. Previous methods require orbital parameters resulting from follow-up observations, whereas the proposed method is so practical to require only tracklets in image sequences. The proposed method is designed to revise estimation of a scale of a breakup event used in the breakup model by applying the observation data correlated with the event. Iterating the scale estimation, one can understand the current situation of fragmentation debris environment better in comparison with initial guess situation. Thus, the proposed method will contribute to enhance effectiveness of search strategies for undiscovered fragmentation debris, estimation of current space situations, and prediction of future space situations. As a result of demonstration of the proposed method it is confirmed that estimated scales of several breakup events are converged after iterations by applying actual observation data acquired by optical search surveys. It is concluded that the proposed method can perform as a part of an iterative search strategy for characterizing spacecraft breakup events. . |
| 207. | Toshiya Hanada, Orbital Debris Modeling and Applications at Kyushu University, The 29th International Symposium on Space Technology and Science, 2013.06, The orbital debris modeling, which describes debris generation and orbit propagation, can build orbital debris evolutionary models as essential tools to predict the current or future orbital debris populations, and also to discuss what and how to do for orbital debris mitigation and remediation. The orbital debris modeling can also devise an effective search strategy applicable for breakup fragments in the geostationary region using ground-based optical sensors, and to evaluate the effectiveness of space-based measurements of objects not tracked from the ground, both to contribute to space situational awareness. Another application of the orbital debris modeling is to estimate attitude motion of space objects to be removed for environmental remediation. This paper briefly introduces efforts being made at Kyushu University in the area of orbital debris modeling and applications. . |
| 208. | Saori Ikeda, Yoshihide Sugimoto, Yasuhiro Kawakatsu, Toshiya Hanada, Systematic Analysis of Venus Earth Gravity Assist (VEGA) Sequence and Its Application to Mission Design, The 29th International Symposium on Space Technology and Science, 2013.06. |
| 209. | Toshiya Hanada, Hideaki Hinagawa, Hongru Chen, Hiroaki Hamada, Shingo Ikemura, Attitude Motion Under Full Orbit Perturbations, The 29th International Symposium on Space Technology and Science,, 2013.06, This paper introduces an effort on going at Kyushu University to precisely describe attitude motion under full orbit perturbations. Five people in total are participating in this effort because of their own objectives. For example, some people apply this effort to understand dynamics of light curve, the change of light intensity or visible magnitude of space objects in optical measurements. Other people apply this effort to conduct a feasibility study of using small satellites to demonstrate wireless power transmission in space. This effort introduces a reference frame being affected by orbit perturbations and the mutual coupling effect of orbit perturbations that generate external torques to change the attitude. This paper focuses on attitude dynamics of a small satellite with relatively low moments of inertia under full orbit perturbations and provides some interesting results and outcome from this effort. . |
| 210. | Yuya Ariyoshi, Toshiya Hanada, Satomi Kawamoto, Influence of Small Satellites’ Post-mission Disposal with Enlarging Effective Cross-sectional Area, The 29th International Symposium on Space Technology and Science, 2013.06, Developers of small satellites may think of enlarging their effective cross-sectional area to minimize the long-term presence in the low Earth orbit region. However, the enlargement of their effective cross-sectional area causes the temporal increase of cumulative probability of accidental collisions. This paper evaluates the influence of small satellites’ post-mission disposal by enlarging their cross-sectional area on the future population using an orbital debris environment evolutionary model. According to the result of the future projections, the small satellites’ post-mission disposals by enlarging the effective cross-sectional area have the potential risk of increasing the accidental collision. However small satellites are inserted into orbit below 800 km in this paper, the fragments to be generated by collision expected to decay within short term. The effective number of objects below 2,000 km altitude is not different between the case with post-mission disposals and the case without post-mission disposals.. |
| 211. | Toshiya Hanada, Orbital Debris Modeling and Applications at Kyushu University, Asia-Pacific Conference on Aerospace Technology and Science, 2013.05, The orbital debris modeling can build evolutionary models as essential tools to predict the current or future orbital debris populations, and also to discuss what and how to do for orbital debris mitigation and environmental remediation. The orbital debris modeling can also devise an effective search strategy applicable for breakup fragments in the geostationary region using ground-based optical sensors, and to evaluate the effectiveness of space-based measurements of objects not tracked from the ground, both to contribute to space situational awareness. Another application of the orbital debris modeling is to estimate attitude motion of space objects to be removed for environmental remediation. This paper briefly introduces efforts into orbital debris modeling and applications at Kyushu University. . |
| 212. | Hongru Chen, Huixin Liu, Toshiya Hanada, Atmospheric Density Modeling Using Neural Networks, Japan Geoscience Union (JpGU) Meeting 2013, 2013.05. |
| 213. | 花田 俊也, 松本 晴久, 北澤 幸人, 柳沢 俊史, 動的宇宙ごみ環境モデルの研究, 日本航空宇宙学会 第44期年開講宴会, 2013.04, This paper briefly introduces a dynamic model of the orbital debris environment to provide a prompt and clear understanding. To dynamically describe the environment knowledge is necessary to be updated based on real-time measurements. This paper also introduces a measurement network by combining in-situ measurements and ground-based optical observations.. |
| 214. | Tagawa, M., Yanagisawa, T., Toshiya Hanada, Space-based Short Range Observations for LEO Debris, the Sixth European Conference on Space Debris, 2013.04. |
| 215. | Ae, K., Uetsuhara, M., Toshiya Hanada, IDEA the Project for In-situ Debris Environmental Awareness, the Sixth European Conference on Space Debris, 2013.04. |
| 216. | Uetsuhara, M., Toshiya Hanada, Kitazawa, Y., Yanagisawa, T., A Search for Possible Breakup Fragments in the Geostationary Region, the Sixth European Conference on Space Debris, 2013.04. |
| 217. | Kitazawa, Y., Matsumoto, H., Okudaira, O., Kimoto, Y., Toshiya Hanada, Faure, P.,, Akahoshi, Y., Hattori, M., Karaki, A., Sakurai, A., Funakoshi, K., Yasaka, T., Research and Development on In-situ Measurement MMOD sensors at JAXA, the Sixth European Conference on Space Debris, 2013.04. |
| 218. | Liou, J.-C., Anilkumar, A. K., Bastida Virgili, B., Toshiya Hanada, Krag, H., Lewis, H., Raj, M. X. J., Rao, M. M., Rossi, A., Sharma, R. K., Stability of the Future LEO Environment - An IADC Comparison Study, the Sixth European Conference on Space Debris, 2013.04. |
| 219. | 山岡 均, 平山 寛, 藤原 智子, 花田 俊也, 鈴木 右文, 大学教育における汎学科の天体・宇宙観測科目の実践, 日本天文学会2013年春季年会, 2013.03. |
| 220. | Hinagawa Hideaki, Hanada Toshiya, Preliminary Simulation for Light Curves of Rocket Body in LEO, The 23rd AAS/AIAA Space Flight Mechanics Meeting, 2013.02, Orbital debris has become an inevitable problem for the future space exploration, and spacecraft is suggested to remove orbital debris. To fulfill this mission, you need to know target’s attitude motion when installing a mitigation-related device. To support, we developed a simulator of orbit, attitude, and light curve to see how an object behaves. This paper presents a process to simulate virtual rocket body’s observation in LEO assuming an existing telescope in Kyushu University, and to estimate the triaxial ratio, the spin axis, and the shape model. The real observation is supposed to be held in the near future.. |
| 221. | Uetsuhara Masahiko, Hanada Toshiya, Yanagisawa Toshifumi, Kitazawa Yukihito, Spacecraft Explosion Event Characterization Using Correlated Observations, The 23rd AAS/AIAA Space Flight Mechanics Meeting, 2013.02, This paper aims to characterize a spacecraft explosion event using correlated observations. Outcomes of the characterization measure will enable us to make current space situational awareness accurate, and to predict realistic future space situations. An event to be characterized in this paper is a breakup of the rocket-body Titan 3C Transtage (1968-081E) exploded at 09:31 GMT on 21 February 1992 in the geostationary region. Characteristics to be evaluated include delta-velocity (ΔV) given to each fragment though the event, and a size distribution of the breakup fragments (i.e., the number of fragments generated by the event). This paper also discusses how effective the evaluated characteristics of a breakup event will contribute to re-visiting observation plans for the breakup fragments. . |
| 222. | 花田俊也, 九州大学における宇宙ゴミのモデリングとその応用について, 在福岡アメリカ領事館 日米宇宙協力シンポジウム 「２１世紀の日米宇宙開発におけるスペースデブリの影響と課題」, 2013.01. |
| 223. | 田川真，花田俊也，柳沢俊史，松本晴久，北澤幸人, 軌道上光学センサによる LEO デブリ観測, 第５回スペースデブリワークショップ, 2013.01, スペースデブリの存在は持続的な宇宙開発利用に対する大きな脅威である．特に地球低軌道（LEO）には追跡されている宇宙機のおよそ7割が集中しており，衝突による破砕リスクが高いため早急な対策が必要である．衝突による破砕を防止するために有効な手段の一つが，軌道上物体の高精度な追跡情報に基づく衝突回避運用である．現状で，LEOにおいて定常的に追跡されている物体サイズの下限はおよそ10cmである．本研究では，LEOに配置した光学センサによって観測能力を向上させることを提案する．効果的なシステム提案を行うためには，LEO同士の観測における能力評価を適切に行う必要がある．著者らは能力評価のツールとして軌道上観測シミュレータの開発を進めている．また軌道上観測結果に対する初期軌道推定手法やフィルタの検討も行なっている．それらツール開発や検討結果の現状とあわせて技術的課題などについて報告を行う．. |
| 224. | 上津原正彦，花田俊也，柳沢俊史，北澤幸人, 静止軌道周辺の破砕事象の観測とモデル化, 第５回スペースデブリワークショップ, 2013.01, 昨今活発に議論されているデブリの発生防止策・低減策の立案には，軌道上のデブリ環境を推定・予測した数値計算結果が積極的に用いられている．時々刻々と変化するデブリ環境に対して推定・予測結果の不確定性を抑えるためには観測・モデル化技術の向上が必要不可欠である．本研究の目的は，静止軌道周辺で発生した破砕事象の観測とモデル化である．運用中の人工衛星が約400機存在する重要な領域である静止軌道周辺では，未知デブリ(起源未同定のデブリ)がこれまでに数多く発見されている．未知デブリの起源は破砕を起こした宇宙機である可能性が高い．本発表では，観測における破砕事象の識別や未知デブリの起源同定方法，そして観測結果に基づく個々の破砕事象のモデル化方法について紹介する．. |
| 225. | 北澤幸人，松本晴久，奥平修，木本雄吾，Pauline Faure，服部真希，花田俊也，唐木敦，桜井晃，船越国弘，八坂哲雄, 軌道上微小デブリ計測技術の研究開発 -JAXA 宇宙環境グループでの開発センサを中心に-, 第５回スペースデブリワークショップ, 2013.01, 軌道上微小デブリ（ダスト）計測の国内での研究開発を概観するとともにJAXA宇宙環境グループで開発中のアクティブセンサの開発状況について報告する。軌道上ダスト計測の研究開発は１９８０年代後半からメテオロイドの計測を目的として活発化した。アクティブ型の計測器は１９９０年の「ひてん」（Muses-A）に搭載されたMDC（Munich Dust Counter）が日本最初の搭載である。一方、パッシブ型の計測器は宇宙科学研究所で計画された彗星からのサンプルリターンミッション(SOCCOR計画)での研究成果をベースに開発された「キャリブレーテッド・エアロジェル」を用いたダストコレクタが1997年にスペースシャトルに搭載されたのが最初である。その後、アクティブ型、パッシブ型とも多くの研究が行われてきている。JAXA宇宙環境グループは諸外国で計測実績がなく、かつ、宇宙機への影響が懸念されるサイズ領域である大きさ１００μｍ～数ｍｍのデブリの存在量の計測を目的としたアクティブ型計測器を開発した。このセンサは２０１４年の「こうのとり」（HTV）に搭載され実装実証試験を行う予定である。 . |
| 226. | 有吉雄哉，花田俊也，河本聡美, デブリ推移モデルによる将来予測, 第５回スペースデブリワークショップ, 2013.01, 宇宙航空研究開発機構と九州大学は，デブリ推移モデルの開発・維持と推移モデルを用いたデブリ分布の予測を行っている．このデブリ推移モデルは10 cm以上の軌道上物体の軌道伝播と衝突率の計算・判定により将来のデブリ分布を予測するものである．これまでに図のような低軌道でのデブリ分布の不安定性の確認やデブリ除去の効果について，推移モデルを用いて予測を行ってきた．本発表では，これらデブリ推移モデルによる結果として，特に種々のデブリ低減対策や除去条件を仮定した場合の将来のデブリ分布の予測結果について紹介する．. |
| 227. | Toshiya Hanada, Yukihito Kitazawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Research Topics for Asia-Pacific Regional Collaboration in the Area of Orbital Debris Issues, Workshop on the Protection of Space Environment, sponsored by Ministry of Foreign Affairs of Japan, in Kuala Lumpur, 2012.12. |
| 228. | Toshiya Hanada, Yukihito Kitazawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Research and Development on Space Debris Observations and Measurements, The 19th Session of the Asia-Pacific Regional Space Agency Forum (APRSAF-19), 2012.12. |
| 229. | 麻生 茂, 八坂 哲雄, 大田 治彦, 花田 俊也, 谷 泰寛, 室園 昌彦, 平山 寛, 鶴田 佳宏, 大西 俊輔, 大村 勝俊, 新井 康平, 西尾 正則, 趙 孟佑, 九州発地球観測超小型人工衛星QSAT-EOSの開発について, 第56回宇宙科学技術連合講演会, 2012.11. |
| 230. | 池田 沙織, 川勝 康弘, 花田 俊也, Campagnola Stefano, 杉本 理英, 金星・地球スイングバイ(VEGA)軌道の特性解析, 第56回宇宙科学技術連合講演会, 2012.11. |
| 231. | 土井 彰, 花田 俊也, IDEA: In-situ Debris Environmental Awareness, 第56回宇宙科学技術連合講演会, 2012.11. |
| 232. | 田川真, 花田 俊也, 北澤幸人, 柳沢俊史, スペースデブリ軌道上光学観測のミッション解析について, 第56回宇宙科学技術連合講演会, 2012.11. |
| 233. | 平山 寛, 山岡 均, 藤原 智子, 鈴木 右文, 花田 俊也, ペガスス望遠鏡を利用した大学高年次の宇宙教育, 第56回宇宙科学技術連合講演会, 2012.11. |
| 234. | 有吉 雄哉, 花田 俊也, 除去対象デブリの選定方法とその効果, 第56回宇宙科学技術連合講演会, 2012.11. |
| 235. | 泉山卓, 樋川治, 大塚健功, 松本晴久, 奥平修, 柳沢俊史, 花田 俊也, 田川真, 微小デブリ観測システム／センサの検討, 第9回宇宙環境シンポジウム, 2012.11. |
| 236. | Yuya Ariyoshi, Toshiya Hanada, Satomi Kawamoto, How Can We Identify Colliding Objects to Be Removed?, 63rd International Astronautical Congress, 2012.10, This paper discusses how we can identify colliding objects to be removed from the low Earth orbit region for sustainable space development and utilization for humankind. Here we compare two different approaches to identify colliding objects to be removed. One approach keeps a view on the possibility of multiple removals. Thus, this approach specifies orbital regions where objects are crowded, and then compares mass between the objects in the crowded region to select candidates. Another approach thinks of impact on the current/future space debris environment. Thus, this approach compares the cumulative probability of accidental collision and/or the expected number of fragments added to the environment due to the accidental collisions to select candidates. Comparison in the effectiveness between the four different approaches in total will be conducted through future projections of the space debris environment in the low Earth orbit region. This paper uses NEODEEM, a space debris evolutionary model for the near Earth orbit region, to conduct this comparison.. |
| 237. | Makoto Tagawa, Toshiya Hanada, Yukihito Kitazawa, Mission Analysis of the Space-based Optical Observation for Orbital Debris, 63rd International Astronautical Congress, 2012.10. |
| 238. | Toshifumi Yanagisawa, Hirohisa Kurosaki, Hajime Banno, Yukihito Kitazawa, Masahiko Uetsuhara, Toshiya Hanada, Comparison Between Four Detection Algorithms for GEO Objects, The 13th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2012.09. |
| 239. | Masahiko Uetsuhara, Toshifumi Yanagisawa, Daisuke Kinoshita, Toshiya Hanada, Yukihito Kitazawa, Collaborative Observations to Search 1968-081E Fragments, The 39th COSPAR Scientific Assembly, 2012.07. |
| 240. | Yoshitaka Nakaniwa, Masahiko Uetsuhara, Toshiya Hanada, Practical Method to Identify Orbital Anomaly as Spacecraft Breakup in the Geostationary Region, The 39th COSPAR Scientific Assembly, 2012.07. |
| 241. | Toshifumi Yanagisawa, Hirohisa Kurosaki, Masahiko Uetsuhara, Daisuke Kinoshita, Toshiya Hanada, Yukihito Kitazawa, Detection of Small Sized GEO Debris Using FPGA Based Stacking Method, The 39th COSPAR Scientific Assembly, 2012.07. |
| 242. | Yukihito Kitazawa, Haruhisa Matsumoto, Toshiya Hanada, Atsushi Karaki, Akira Sakurai, Kunihiro Funakoshi, Tetsuo Yasaka, Maki Hattori, Sunao Hasegawa, Development In-situ Micro-debris Sensor, The 39th COSPAR Scientific Assembly, 2012.07. |
| 243. | Hideaki Hinagawa, Toshiya Hanada, Applicatin Possibility of Light Curve Inversion Method Regarding Space Debris, the 22nd JAXA Workshop on Astrodynamics and Flight Mechanics, 2012.07. |
| 244. | Saori Ikeda, Yasuhiro Kawakatsu, Toshiya Hanada, Yoshihide Sugimoto, Characteristics of the Venus Earth Gravity Assist (VEGA), the 22nd JAXA Workshop on Astrodynamics and Flight Mechanics, 2012.07. |
| 245. | 上津原正彦, 北澤幸人, 花田俊也, 柳沢俊史, 未知スペースデブリの効率的な探索方法の研究, 日本公開天文台協会第7回全国大会, 2012.06. |
| 246. | 花田俊也, 「プラネテス」は作り話ではない？地球低軌道における宇宙ごみ環境の不安定性について, 日本機械学会 関西支部 関西学生会 学生員卒業研究発表講演会, 2012.03, ΠΛΑΝΗΤΕΣ(プラネテス)は長年にわたる宇宙開発で廃棄されてきた人工衛星などの「スペースデブリ（宇宙ごみ）」を拾い集める日々を送る回収員を描いた日本のSF漫画（幸村誠原作）である．近い将来，宇宙ごみは人間の生活を脅かすまでに増え，回収しなければならなくなるのだろうか．国際機関間スペースデブリ調整委員会が結成した研究チームの一員として，著者が現在の宇宙ごみ環境の不安定性を検証した結果について議論した．. |
| 247. | Y. Kitazawa, H. Matsumoto, T. Hanada, A. Sakurai, K. Funakoshi, T. Yasaka, S. Hasegawa, M. Nakamura, Development of In-situ Micro-debris Measurement Sensor, The Sixteenth ISU (International Space University) Annual International Symposium, 2012.02. |
| 248. | Y. Ariyoshi, T. Hanada, S. Kawamoto, Y. Kitazawa, How Can We Identify Colliding Objects to be Removed for Safe and Secure Space?, The Sixteenth ISU (International Space University) Annual International Symposium, 2012.02. |
| 249. | 花田俊也, 柳澤俊史, 北澤幸人, 未知スペースデブリの効率的な探索方法の研究, 第４回スペースガード研究会, 2011.12, This paper proposes to apply the orbital debris modeling techniques to devise an effective search strategy applicable for breakup fragments in the geostationary region. The orbital debris modeling techniques describe debris generation and propagation to effectively conduct predictive analyses of space objects that include characterizing, tracking and predicting the behavior of individual and groups of space objects. Therefore, the techniques enable us to predict population of debris from a specific breakup. The population prediction specifies effectively when, where and how we should conduct optical measurements using ground-based telescopes. The orbital debris modeling techniques also enable us to predict motion of debris in successive images. The motion prediction specifies effectively and precisely how we should process successive images of objects in the geostationary region, taken with ground-based telescopes. This paper also validates the proposed search strategy through actual observations, targeting the US Titan IIIC transtage explosion in the geostationary region. . |
| 250. | Yuya ARIYOSHI, Toshiya HANADA, Satomi KAWAMOTO, How Small Satellite Can Be Hazardous in Comparison to Massive Satellites, 3rd Nano-satellite Symposium, 2011.12. |
| 251. | Masahiko UETSUHARA, Toshiya HANADA, Makoto TAGAWA, Hideaki HINAGAWA, The IDEA Project Team, IDEA: In-situ Debris Environmental Awareness, 3rd Nano-satellite Symposium, 2011.12. |
| 252. | 花田俊也, 世界トップのスペースデブリ環境評価技術の確立を目指して, 日本機械学会, 2011.11. |
| 253. | 北澤幸人, 松本晴久, 花田俊也, 柳澤俊史, スペースデブリ観測／計測と宇宙デブリセンサの開発, 第８回宇宙環境シンポジウム, 2011.10. |
| 254. | 花田俊也，柳澤俊史，北澤幸人, 未知スペースデブリの効率的な探索方法の研究, 第８回宇宙環境シンポジウム, 2011.10. |
| 255. | Yukihito Kitazawa, Haruhisa Matsumoto, Toshiya Hanada, Toshifumi Yanagisawa, Atsushi Karaki, Akira Sakurai, Funakoshi Kunihiro, Tetsuo Yasaka, Sunao Hasegawa, Maki Nakamura, Development of In-situ Micro-debris Measurement System, 62nd International Astronautical Congress, 2011.10. |
| 256. | Masahiko Uetsuhara, Yukihito Kitazawa, Toshifumi Yanagisawa, Toshiya Hanada, Effective Search Strategy Applicable for Breakup Fragments in the Geostationary Region, The 12th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2011.09. |
| 257. | Toshiya Hanada, Kazuaki Maniwa, How Small Satellites Can Comply with the Space Debris Mitigation Guidelines, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 258. | Yuki Tsutsumi, Hiroshi Hirayama, Toshiya Hanada, Hazards of Electrodynamic Tether to Other Spacecraft, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 259. | Yuya Ariyoshi, Toshiya Hanada, Yukihito Kitazawa, Aritsune Kawabe, Effectiveness of Passive Orbital Debris Removal for Future Environment, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 260. | Hiroshi Hirayama, Shuichi Kashima, Toshiya Hanada, Yukihito Kitazawa, Aritsune Kawabe, Efficient Shape for Passive Orbital Debris Removal Satellite, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 261. | Shigeru Aso, Tetsuo Yasaka, Yasuhiro Tani, Toshiya Hanada, Masahiko Murozono, Masatoshi Omura, Yoshihiro Tsuruda, Shunsuke Onishi, Kohei Arai, Mengu Cho, Masanori Nishio, QSAT-EOS: 50kg-class Small Satellite for Earth Observation System Demonstration, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 262. | Koki Fujita, Toshiya Hanada, Yukihito Kitazawa, An Image Tracking Method for Debris on GEO Using Optical Flow Algorithm, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 263. | Masahiko Uetsuhara, Toshiya Hanada, Toshifumi Yanagisawa, Hirohisa Kurosaki, Hitoshi Yamaoka, Yukihito Kitazawa, Search Observation of Lost Fragments from Explosion Breakup Event in GEO, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 264. | Hideaki Hinagawa, Toshiya Hanada, Precise Determination of Physical Properties of Space Objects, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 265. | Makoto Tagawa, Toshiya Hanada, Yukihito Kitazawa, Aritsune Kawabe, Orbital Debris Observation Using Space-based LADAR system, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 266. | Yukihito Kitazawa, Haruhisa Matsumoto, Akira Sakurai, Kunihiro Funakoshi, Tetsuo Yasaka, Toshiya Hanada, Sunao Hasegawa, Status Report of Development of a Sensor for In-situ Space Dust Measurement, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 267. | Hongru Chen, Masahiko Uetsuhara, Toshiya Hanada, IDEA: In-situ Debris Environmental Awareness, The 28th International Symposium on Space Technology and Science, 2011.06. |
| 268. | Toshiya Hanada, ΠΛΑΝΗΤΕΣ Could Be a True Story? – Instability of the Current Debris Population in LEO –, 国立中央大学 天文研究所（Graduate Institute of Astronomy, National Central University）, 2011.03. |
| 269. | Masanori Nishio, Yuji Sakamoto, Ryota Hayashi, Hiroshi Katanoda, Hideki Ujihara, Toshiya Hanada, Yuji Harada, Shinichi Teshima, Kazuki Hamada, Shinichi Nagaie, Fumihiko Hori, Takeo Mutou, Nanami Sakamoto, Akihiro Hamada, Takashi Suda, Yuki Tsutsumi, Haruka Ohta, Yuya Tateyama, Takehito Morimatsu, Mitsuru Ohyashiki, Ryunosuke Nakamura, Tetsuro Sato, Terumasa Miyahara, Mitsuhiro Hashiguchi, Naruo Higashi1, Akira Fujii, and Tsutomu Tokifuji, In-orbit Verification of a Pico-satellite for Atmospheric Water Vapor Observations, The Second Nano-Satellite Symposium, 2011.03. |
| 270. | 木村真一, 河本聡美, 中西洋喜, 大川恭志, 北澤幸人, 澤井秀次郎, 福田盛介, 中谷幸司, 坂井真一郎, 久木田明夫, 坂井智彦, 佐原宏典, 竹ヶ原春貴, 能見公博, 外本伸治, 花田俊也, 趙孟佑, デブリ除去に向けた非協力接近・調査ミッションの 提案, 第1回小型科学衛星シンポジウム, 2011.03. |
| 271. | 眞庭知成，花田俊也, 環境推移モデルによるスペースデブリの長期環境推移について, 第３回スペースガード研究会・第４回スペースデブリワークショップ, 2010.12. |
| 272. | 河本聡美，大川恭志，照井冬人，西田信一郎，北村正治，木部勢至朗，花田俊也，白坂成功, デブリ除去の必要性とストラテジ, 第３回スペースガード研究会・第４回スペースデブリワークショップ, 2010.12. |
| 273. | 有吉雄哉，嘉嶋秀一，平山寛，花田俊也，北澤幸人，川辺有恒，松本晴久, 低密度材料を用いた受動的なスペースデブリの除去方法, 第３回スペースガード研究会・第４回スペースデブリワークショップ, 2010.12. |
| 274. | 北澤幸人，松本晴久，桜井晃，船越国広，八坂哲雄，花田俊也，長谷川直, ダスト計測技術の研究開発, 第３回スペースガード研究会・第４回スペースデブリワークショップ, 2010.12. |
| 275. | 上津原正彦，田川真，花田俊也, 次世代型デブリ観測の提案, 第３回スペースガード研究会・第４回スペースデブリワークショップ, 2010.12. |
| 276. | 北澤幸人，花田俊也，柳沢俊史，松本晴久，赤星 保浩，仁田工美，河本聡美, スペースデブリ環境について –デブリ環境研究紹介–, 2010.10. |
| 277. | Yukihito Kitazawa, Toshiya Hanada, Sunao Hasegawa, Funakoshi Kunihiro, Haruhisa Matsumoto, Akira Sakurai, Tetsuo Yasaka, Status Report of Development of a Sensor for In-Situ Space Dust Measurement, 61st International Astronautical Congress, 2010.09. |
| 278. | Makoto TAGAWA, Toshiya HANADA, Kozue HASHIMOTO, Yukihito KITAZAWA, Aritsune KAWABE, Orbital Debris Observation via Laser Illuminated Optical Measurement Techniques, The 11th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2010.09. |
| 279. | Masahiko Uetsuhara, Toshiya Hanada, Hitoshi Yamaoka, Tomoko Fujiwara, Toshifumi Yanagisawa, Hirohisa Kurosaki, Yukihito Kitazawa, Detection of Faint GEO Objects Using Population and Motion Prediction, The 11th Annual Advanced Maui Optical and Space Surveillance Technologies Conference, 2010.09. |
| 280. | Yuya Ariyoshi, Masataka Yamada, Hiroshi Hirayama, Toshiya Hanada, Yukihito Kitazawa, Aritsune Kawabe, Haruhisa Matsumoto, Passive Orbital Debris Removal Using Special Density Materials, 38th COSPAR Scientific Assembly, 2010.07. |
| 281. | Yukihito Kitazawa, Haruhisa Matsumoto, Akira Sakurai, Tetsuo Yasaka, Kunihiro Funakoshi, Toshiya Hanada, Sunao Hasegawa, Toshihiko Kadono, Status Report of Development of a Sensor for In-Situ Space Dust Measurement, 38th COSPAR Scientific Assembly, 2010.07. |
| 282. | Toshiya Hanada, Jer-Chyi Liou, Theoretical and Empirical Analysis of the Average Cross-sectional Areas of Breakup Fragments, 38th COSPAR Scientific Assembly, 2010.07. |
| 283. | S. Kawamoto, Y. Ohkawa, S. Nishida, S. Kitamura, S. Kibe, T. Hanada, M. Mine, Studies on Active Debris Removal in Japan, European Workshop on Active Debris Removal, 2010.06. |
| 284. | T. Narumi, Y. Akahoshi, J. Murakami, T. Hanada, Numerical Simulation of Spacecraft Fragmentation for Hypervelocity Impact, Hypervelocity Impact Symposium, 2010.04. |
| 285. | T. Hanada, J. Murakami, Y. Tsuruda, J.-C., Liou, Microsatellite Impact Fragmentation, Hypervelocity Impact Symposium, 2010.04, This paper summarizes recent microsatellite impact tests conducted under contract with the NASA Orbital Debris Program Office. The motivation for the impact tests is twofold. First, as new satellite materials continue to be developed, there is a need for impact tests on satellites made of modern materials to better characterize the outcome of future on-orbit satellite fragmentation. Second, it is necessary to extend tests to different velocity regimes to cover potential low-velocity collisions in the geosynchronous region. To date, seven impact tests have been carried out. All microsatellites were totally fragmented and generated more than 1000 fragments each. Fragments down to about 2 mm in size were collected, measured, and analyzed. Main summary of this paper includes size, mass, area-to-mass ratio, and shape distributions of fragments generated from each test and how they vary with size, material type, and impact parameters. . |
| 286. | Toshiya Hanada, Microsatellite Impact Tests, 北京理工大学, 2010.04. |
| 287. | Toshiya Hanada, Orbital Debris Related Researches at Kyushu Iniversity, 中国航天科技集団公司 中国空間技術研究院, 2010.03. |
| 288. | T. Hanada, Y. Kitazawa, A. Kawabe, H. Matsumoto, S. Kawamoto, Small and Medium Orbital Debris Removal Using Special Density Materials, International Conference on Orbital Debris RemovalDecember 8-10, 2009, 2009.12. |
| 289. | S. Kawamoto, Y. Ohkawa, S. Nishida, S. Kitamura, S. Kibe, T. Hanada, M. Mine, Strategies and Technologies for Cost Effective Removal of Large Sized Debris, International Conference on Orbital Debris RemovalDecember 8-10, 2009, 2009.12. |
| 290. | Toshiya Hanada, ΠΛΑΝΗΤΕΣ Could Be a True Story? – Instability of the Current Debris Population in LEO –, Space Environment Symposium, 2009.10. |
| 291. | Toshiya Hanada, A Summary of My Research Activities at JSC, 2009.09. |
| 292. | Y. Kitazawa, H. Matsumoto, A. Sakurai, T. Yasaka, K. Funakoshi, T. Hanada, S. Hasegawa, Development of a New Type Sensor for Micrometeoroid and Space Debris In-situ Measurement, Aeroballistic Range Association, 2009.09. |
| 293. | Toshiya HANADA, Junko MURAKAMI, Yoshihiro TSURUDA, Micro-satellite Impact Testing, International Symposium on Space Technology and Science, 2009.07. |
| 294. | Toshiya HANADA, Junko MURAKAMI, Yoshihiro TSURUDA, Micro-satellite Impact Testing, International Symposium on Space Technology and Science, 2009.07. |
| 295. | Toshiya Hanada, Jer-Chyi Liou, Shape Distribution of Fragments From Microsatellite Impact Tests, European Conference on Space Debris, 2009.04. |
| 296. | Y. Kitazawa, A. Sakurai, T. Yasaka, K. Funakoshi, T. Hanada, and H. Matsumoto, Development of a New Type Sensor for Micrometeoroid and Space Debris In-situ Measurement at JAXA, European Geosciences Union General Assembly, 2009.04. |
| 297. | Junko Murakami, Toshiya Hanada, Jer-Chyi Liou, Eugene Stansbery, Micro-satellite Impact Tests to Investigate Multi-Layer Insulation Fragments, European Conference on Space Debris, 2009.03. |
| 298. | 花田俊也, Toward the Spacecraft Disaster Forecast (III)（宇宙機災害予測に向けて(III)）, 2009.03. |
| 299. | Toshiya Hanada, Jer-Chyi Liou, Takashi Nakajima, Eugene Stansbery, Outcome of Recent Satellite Impact Experiments, 2008.07. |
| 300. | Yukihito Kitazawa, Shinya Fukushige, Masato Uchino, Yasuhiro Akahoshi, Tateo Goka, Akira Sakurai, Tetsuo Yasaka, Kunihiro Funakoshi, Toshiya Hanada, Haruhisa Matsumoto, Takaaki Noguchi, Riyo Yamanaka, Yugo Kimoto, Mineo Suzuki, Current Problems of Debris Environment Models and Related Studies of JAXA, 2008.07. |
| 301. | Ttoshiya Hanada, Jer-Chyi Liou, Paula H. Krisko, Takashi Nakajima, For Better Calculation of the Average Cross-Sectional Area of Breakup Fragments, International Symposium on Space Technology and Science, 2008.06. |
| 302. | 花田俊也, Toward the Spacecraft Disaster Forecast (II)（宇宙機災害予測に向けて(II)）, 2008.03. |
| 303. | Toshiya Hanada, Outcome of Recent Satellite Impact Experiments, The 3rd Space Debris Workshop, 2008.01. |
| 304. | Kosuke Sakuraba, Yoshihiro Tsuruda, Toshiya Hanada, Jer-Chyi Liou, Yasuhiro Akahoshi, Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model, Hypervelocity Impact Symposium, 2007.09. |
| 305. | Toshiya HANADA, QSAT the Polar Plasma Observation Satellite, 2007.06. |
| 306. | 花田俊也, Toward the Spacecraft Disaster Forecast（宇宙機災害予測に向けて）, 2007.03. |
| 307. | Koki Fujita, Toshiya Hanada, Estimation Method of Micro-debris Population from Solar Array Images, International Astronautical Congress, 2006.10. |
| 308. | Toshiya Hanada, Jer-Chyi Liou, Yasuhiro Akahoshi, Comparison between New Impact Test Results and the NASA Standard Breakup Model, International Astronautical Congress, 2006.10. |
| 309. | Carmen Pardini, Toshiya Hanada, Paula H. Krisko, Benefits and Risks of Using Electrodynamic Tethers to De-orbit Spacecraft, International Astronautical Congress, 2006.10. |
| 310. | Toshiya Hanada, Jer-Chyi Liou, Comparison of Fragments Created by Low- and Hyper-velocity Impacts, COSPAR Scientific Asembley, 2006.07. |
| 311. | Ttoshiya Hanada, Properties of Fragments from Low-velocity Impacts on Micro Satellite, International Symposium on Space Technology and Science, 2006.06. |
| 312. | 花田俊也, Hypervelocity Impacts viewed from Orbital Debris Modeling, 東京工業大学応用セラミックス研究所ワークショップ〜セキュアマテリアルを求めて〜, 2006.03. |
| 313. | Carmen Pardini, Luciano Anselmo, Toshiya Hanada, Hiroshi Hirayama, Assessing the Vulnerability to Debris Impacts of Electrodynamic Tethers during Typical De-orbting Missions, European Conference on Space Debris, 2005.04. |
| 314. | T. Hanada, Y. Akahoshi, Low-velocity Catastrophic Impact on Micro Satellite, European Conference on Space Debris, 2005.04. |
| 315. | Yasushiro Akahoshi, Tetsuo Yasaka, Shoji Harada, Modifying the NASA Standard Breakup Model to be Applied to Low-Velocity Collision, International Astronautical Congress, 2003.10. |
| 316. | Hitoshi Hirayama, Tesuo Yasaka, In-Situ Debris Measurements in MEO/HEO using Onboard Spacecraft Inspection System, World Space Congress, 2002.10. |
| 317. | Hitoshi Hirayama, Tesuo Yasaka, Understanding Orbit Perturbations to Devise Debris Search Strategies in GEO, International Symposium on Space Technology and Science, 2002.06. |
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