| Toshiya Hanada | Last modified date：2024.04.15 |
Professor /
Space System Engineering /
Department of Aeronautics and Astronautics /
Faculty of Engineering
Presentations
| 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. | Optical observation and investigation into Fragmentation of Russian EKRAN 2 Spacecraft. |
| 6. | Optical observation and investigation into Fragmentation of Russian EKRAN 2 Spacecraft. |
| 7. | Optical observation and investigation into Fragmentation of Russian EKRAN 2 Spacecraft. |
| 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. | Small Satellite Constellation Design for Meso-scale meteorological Phenomena. |
| 11. | Relative Orbit Control Under Uncertain Accelerations Using Gaussian Process Regression. |
| 12. | Singular problem and drift stability of space-advertisement formation. |
| 13. | An Object Classification Based on Cataloged Objects of Fragmentation Debris Utilizing EISCAT Observation Data. |
| 14. | Close Approach Analysis Method Considering Attitude and Shape with Dual Quaternions. |
| 15. | Gaussian Process Regression for Photometric Attitude Estimation. |
| 16. | Attitude Control of an Uncooperative Satellite by Laser Ablation. |
| 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. | Origin Identification of Breakup Event from In-situ Debris Measurements. |
| 20. | Evaluation of Sustainable Space Development with Considering Climate Change. |
| 21. | Space Debris Environment in the GEO Regime Viewed from Tomo-e Gozen Data. |
| 22. | Analysis of Chaotic Orbits in the Earth–Moon Three–Body Problem Using Data–Driven Analysis. |
| 23. | Analysis of Satellite Attitude Dynamics by Applying a High-Fidelity Solar Radiation Pressure. |
| 24. | Simultaneous Deorbiting of Formation Flying with Non-Cooperative Objects. |
| 25. | Pose Estimation with Dual Quaternions. |
| 26. | Fundamental Research on Explosion Fragmentation Test Methods for A Mock-up Satellite. |
| 27. | Investigation into Fragmentation of the Russian EKRAN 2 Spacecraft. |
| 28. | Effect of Internal Explosion Energy on Satellite Breakup. |
| 29. | A Correlation Analysis between Objects Detected by an EISCAT Radar and Cataloged Ones. |
| 30. | Stabilization of Space-advertisement Satellite Formation. |
| 31. | A Correlation Analysis between Space Debris Detected by an EISCAT Radar and Cataloged Ones. |
| 32. | Origin Identification of Breakup Event from In-situ Debris Measurements. |
| 33. | Effect of Source Location on Mock-up Satellite Fragmentation. |
| 34. | Analysis of Orbital Debris Environment Using Debris Evolutionary Model. |
| 35. | Evaluation of Sustainable Space Development by Considering the Long-term Change in the Upper Atmosphere. |
| 36. | A Study of Utilization and Formulation of Space Debris Index. |
| 37. | Orbit Design for ADR Mission Using Laser Satellite. |
| 38. | Formation Design for Multi-deorbit Using Laser Ablation. |
| 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. | A Correlation Analysis for Specific Fragmentation Space Objects Detected via EISCAT Radar. |
| 51. | Attitude and Orbit Calculation Using Dual Quaternions. |
| 52. | Improvement of Orbit Propagation of Space Debris Focusing on Stepper. |
| 53. | Selection of Targets to Be Removed with Considering Timeliness. |
| 54. | Analytic Observability Analysis of Light Curve with Self-Shadowing. |
| 55. | Orbit Propagation Accuracy from Earth Shadow Reproduction Point of View. |
| 56. | Relative Orbit Estimation of Spacecraft under Unknown Thrust Acceleration. |
| 57. | Attitude Stabilization of Non-Cooperative Satellite Using Laser Ablation. |
| 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. | Orbital Debris Modeling in Kyushu Univ.. |
| 62. | Study of the Environmental Capacity Tolerance of Insertions Using the Orbital Debris Evolutionary Model. |
| 63. | Development of JAXA's Original Baseline File for Debris Evolutionary Model. |
| 64. | Analysis on Attitude Motion of ADR Target in LEO. |
| 65. | Overview of Space Debris from Economics. |
| 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. | Design of the Spacecraft Rendezvous Orbits for ADR to the Large-scale Space Debris in LEO. |
| 69. | Can Space Elevator Survives until its Construction Cost Can Be Recovered?. |
| 70. | 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.. |
| 71. | 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.. |
| 72. | 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.. |
| 73. | 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.. |
| 74. | 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.. |
| 75. | 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.. |
| 76. | 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.. |
| 77. | 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.. |
| 78. | Toshiya Hanada, Towards Long-term Sustainability of Outer Space Activities, The Eleventh Kyushu Univ. – KAIST Symposium on Aerospace Engineering, 2019.12. |
| 79. | Statistical Analysis on Detection of Environmental Changes of Space Debris utilizing In-situ Measurements. |
| 80. | Quantification of satellite mission end risk due to space debris impact. |
| 81. | 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. . |
| 82. | 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.. |
| 83. | 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.. |
| 84. | 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. . |
| 85. | An Identification of Space Debris Utilizing EISCAT Radar Observation. |
| 86. | Environmental Estimation of Sub-millimeter-size Debris Utilizing In-situ Measurements. |
| 87. | Development of “Q-Li” the CubeSat for Verification of Light-Curve Inversion. |
| 88. | Attitude and Inertial Property Estimation for an Asymmetric Object. |
| 89. | Improving Accuracy of Conjunction Assessment using Optical Observation. |
| 90. | 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.. |
| 91. | 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.. |
| 92. | 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.. |
| 93. | 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. |
| 94. | 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. |
| 95. | 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.. |
| 96. | 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.. |
| 97. | 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.. |
| 98. | 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.. |
| 99. | 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.. |
| 100. | 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.. |
| 101. | 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.. |
| 102. | 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.. |
| 103. | 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.. |
| 104. | 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.. |
| 105. | 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. . |
| 106. | 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.. |
| 107. | 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. |
| 108. | 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. . |
| 109. | 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.. |
| 110. | 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.. |
| 111. | 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. . |
| 112. | Evaluation and Improvement of a Determination Method for Sub-millimeter-size Debris Orbital Plane. |
| 113. | Towards A Better Understanding of Space Debris Environment. |
| 114. | Space Debris Environment Changes and Forecasts Associated With Space Weather Activities. |
| 115. | 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.. |
| 116. | IDEA the Project for In-situ Debris Environmental Awareness. |
| 117. | A Determination of Debris Orbital Plane Using More Than One Measurement Satellites. |
| 118. | Innovative Globalization of Space Weather Science and Education Based on International Observation Network. |
| 119. | Current status and future development of "IDEA" the project to monitor sub-millimeter-sized debris environment using small satellites. |
| 120. | 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. |
| 121. | 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. |
| 122. | 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. |
| 123. | 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. |
| 124. | 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. |
| 125. | Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Dynamic Modeling on Micron-Size Orbital Debris, The 30th International Symposium on Space Technology and Science, 2015.07. |
| 126. | 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, [URL], 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.. |
| 127. | Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Dynamic Modeling on Micron-size Orbital Debris Environment, Asian-Pacific Conference on Aerospace Technology and Science, 2015.05. |
| 128. | Investigation on the Observation of LEO objects by Small Optical System. |
| 129. | Orbital Object Detection Algorithm Using Streaks. |
| 130. | Evaluation of the impacts of near-Earth-orbit Debris Removal and Track of Impactful Events' Origin. |
| 131. | Orbital Object Observation Strategy Based on a Global Weather Model. |
| 132. | Orbital Debris Modeling and Applications. |
| 133. | Optical and In-situ Debris Measurements in Collaboration with Space Weather Science and Education. |
| 134. | Feasibility about Mission Aiming at Sensing Attitude Motion of Rocket Body. |
| 135. | Practical Study on General Space Education: Activities of Pegasus Project in Kyushu University. |
| 136. | Observation and Motion Analysis of Artificial Objects in Low Earth Orbit by a Tracking Method. |
| 137. | A moving object detection algorithm using faint streaks. |
| 138. | Dynamic Modeling on Micron-size Orbital Debris Environment. |
| 139. | 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.. |
| 140. | 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.. |
| 141. | 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.. |
| 142. | 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.. |
| 143. | 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.. |
| 144. | 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.. |
| 145. | 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.. |
| 146. | 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.. |
| 147. | 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. |
| 148. | 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. |
| 149. | 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. |
| 150. | 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.. |
| 151. | 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.. |
| 152. | 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.. |
| 153. | 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.. |
| 154. | Study about Identification of Breakup Events by Observation of Micron-size Debris Environmental Fluctuation. |
| 155. | Risk Assessment of Collision between Geostationary Satellite and Its Uncontrolled Neighbors. |
| 156. | Origin Identification of Uncorrelated Fragments from Breakups. |
| 157. | Deliberation of the Method for Measuring Velocity of Micron-size Debris Using Micro Satellite. |
| 158. | In-situ Observation of Micrometeoroid and Orbital Debris by ELMOS. |
| 159. | Small Orbital Debris Tracking Using Space-based Optical System in Low Earth Orbit. |
| 160. | Asia-Pacific Regional Collaboration for Long-term Sustainability of Outer Space Activities. |
| 161. | Influence of Small Satellites on Sustainable Space Utilization. |
| 162. | 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.. |
| 163. | 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.. |
| 164. | 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. |
| 165. | 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. |
| 166. | 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. |
| 167. | 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.. |
| 168. | 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. |
| 169. | 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.. |
| 170. | 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. |
| 171. | 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. . |
| 172. | 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. . |
| 173. | 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. . |
| 174. | 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. . |
| 175. | 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. |
| 176. | 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. . |
| 177. | 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.. |
| 178. | 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. . |
| 179. | Hongru Chen, Huixin Liu, Toshiya Hanada, Atmospheric Density Modeling Using Neural Networks, Japan Geoscience Union (JpGU) Meeting 2013, 2013.05. |
| 180. | Dynamic Modeling on Orbital Debris Environment. |
| 181. | Tagawa, M., Yanagisawa, T., Toshiya Hanada, Space-based Short Range Observations for LEO Debris, the Sixth European Conference on Space Debris, 2013.04. |
| 182. | Ae, K., Uetsuhara, M., Toshiya Hanada, IDEA the Project for In-situ Debris Environmental Awareness, the Sixth European Conference on Space Debris, 2013.04. |
| 183. | 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. |
| 184. | 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. |
| 185. | 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. |
| 186. | 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.. |
| 187. | 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. . |
| 188. | Orbital Debris Modeling and Applications at Kyushu University. |
| 189. | Feasibility study for Space-Based optical observation mission of space Debris. |
| 190. | Measurement and modeling of breakup events in the geostationary region. |
| 191. | R&D on in-situ measurement MMOD sensors at JAXA. |
| 192. | Prediction of Orbital Debris Population with an Orbital Debris Evolutionary Model. |
| 193. | Overview on Kyushu Earth Observation Satellite QSAT-EOS. |
| 194. | Characteristics of the Venus Earth Gravity Assist (VEGA). |
| 195. | IDEA: In-situ Debris Environmental Awareness. |
| 196. | The Mission Analysis of the Space-based Optical Observation for Orbital Debris. |
| 197. | Space Education for Senior Students using Pegasus Telescope. |
| 198. | Selecting Debris to Be Removed and Their Effectiveness. |
| 199. | Masahiko Uetsuhara, Toshifumi Yanagisawa, Daisuke Kinoshita, Toshiya Hanada, Yukihito Kitazawa, Collaborative Observations to Search 1968-081E Fragments, The 39th COSPAR Scientific Assembly, 2012.07. |
| 200. | 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. |
| 201. | 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. |
| 202. | 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. |
| 203. | Effective Search Strategy for Uncorrelated Targets in the Geostationary Region. |
| 204. | 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. |
| 205. | 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. |
| 206. | ΠΛΑΝΗΤΕΣ Could Be a True Story? – Instability of the Current Debris Population in LEO –. |
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