|Toshiya Hanada||Last modified date：2019.04.22|
Professor / Space System Engineering / Department of Aeronautics and Astronautics / Faculty of Engineering
|1.||Kenji Saito, Shinji Hatta, Toshiya Hanada, Digital Currency Design for Sustainable Active Debris Removal in Space, IEEE TRANSACTIONS ON COMPUTATIONAL SOCIAL SYSTEMS, https://doi.org/10.1109/TCSS.2018.2890655, 6, 1, 127-134, 2019.02, Orbital debris (OD) remains as an obstacle to further space development. While efforts are ongoing to avoid newly launched objects becoming debris, the number of debris would still continue to grow because of collisions. Active debris removal (ADR) is an effective measure, but building a sustain- able economic model for ADR remains as a difficult problem. We propose that the cost of removal can be paid by circulating digital currency tokens on a blockchain platform whose values may decrease and/or increase over time, issued by global cooper- ation (a consortium) of parties interested in space development, in exchange with proofs of ADR. The tokens pay their cost by themselves through contributions by the token holders, who are likely to be benefited by removal of debris. This scheme imposes virtually no cost to the consortium. We have generalized this concept as proof of disposal, which, we believe, provides a more accountable foundation for solving social problems with digital currency than many Initial Coin or Cryptoasset Offering in practice today. We evaluated the feasibility of our proposal through a simulation. We conclude that dynamic estimation of the economic values of each ADR and automated pricing of tokens that represent the OD being removed are indeed possible. Actual prototyping of the proposed digital currency system is ongoing..|
|2.||Yutaka Kodama, Masahiro Furumoto, Yasuhiro Yoshimura, Koki Fujita, Toshiya Hanada, Estimation of orbital parameters of broken-up objects from in-situ debris measurements, Advances in Space Research, https://doi.org/10.1016/j.asr.2018.07.034, 63, 1, 394-403, 2019.01, Even sub-millimeter-size debris could cause a fatal damage on a spacecraft. 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 measurements of sub-millimeter-size debris. One of the objectives is to estimate the location of on-orbit satellite fragmentations from in-situ measurements. The previous studies revealed that it is important to find out the right nodal precession rate to estimate the orbital parameters of a broken-up object properly. Therefore, this study derives a constraint equation that applies to the nodal precession rate of the broken-up object. This study also establishes an effective procedure to estimate properly the orbital parameters of a broken-up object with the constraint equation..|
|3.||Yuki ITAYA，Koki FUJITA，Toshiya HANADA, Precise time estimation of on-orbit satellite fragmentations, Acta Astronautica, 152, 415-425, 2018.11, To date, there has been a lot of on-orbit satellite fragmentations since a Thor-Able upper stage exploded in space in 1961. Considering that even sub-millimeter-size debris are a big threat to operational satellites, then it can be said that detailed debris modelling is becoming an urgent task for sustainable space development. For accurate modelling, it is essential to know the accurate time of breakup. However, there is no effective method which can estimate the time precisely. Therefore, this study aims at constructing a new method for estimating the time of breakup precisely. This study focuses on orbital plane as a parameter and derives a new equation. This equation constraints orbital planes of fragments at breakup by using orbital elements of the broken-up object. The ad- vantage of this equation is that the fragments can be evaluated by only inclination and right ascension of the ascending node which can guarantee relatively high accuracy even in a long-term propagation. For the esti- mation, this study proposes a hybrid method which combines the advantages of the constraint equation and the close approach analysis. As a result, by using officially reported data, it was confirmed that this hybrid method can estimate the time of breakup with an error of 1 min or less. It was also suggested that the difference in the estimated time between the hybrid method and the close approach analysis causes a large difference in predicted fragments..|
|4.||Satomi KAWAMOTO，Takayuki HIRAI，Shiki KITAJIMA，Shuji ABE，Toshiya HANADA, Evaluation of Space Debris Mitigation Measures Using a Debris Evolutionary Model, Aerospace Technology Japan, 10.2322/tastj.16.599, 16, 7, 599-603, 2018.11, 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..|
|5.||Masahiro Furumoto, Toshiya Hanada, An environmental estimation model for in-situ measurements of small space debris, Advances in Space Research, https://doi.org/10.1016/j.asr.2018.04.042, 62, 3, 533-541, 2018.08, Space debris smaller than 2 mm that cannot be detected by ground-based observations may lead to a spacecraft’s missions end. There- fore, 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 estimation model with a Sequential Monte Carlo (SMC) filter. First, this paper reviews the previous research that investigated the nature of an orbit on which a piece of debris can be detected through in-situ measurements, and applies this phenomenon to the algorithm of the SMC filter. Second, the proposed model is evaluated by a simulation using MASTER-2009, which is the environmental model developed at European Space Agency. Comparison between the debris distributions predicted by MASTER-2009 and the simulated estimation verifies that the proposed model can estimate the debris environment suffi- ciently. Finally, this paper also investigates the effect of the measurement duration on the estimation. It is concluded, therefore, that the estimation model proposed and evaluated in this paper can provide a better definition of the sub-millimeter-size debris environment with in-situ measurements..|
|6.||Osama Mostafa Ali, Toshiya Hanada, Maneuver of Satellites Constellation for Optimal Continuous Coverage, Imperial Journal of Interdisciplinary Research (IJIR), 3, 9, 967-974, 2017.09, [URL], This work aims to study the effect of conservative and non-conservative forces, like Earth’s oblateness, third-body gravitational attraction and atmospheric drag on satellites in high elliptical Molniya and Tundra orbit types for coverage of high latitude regions. This work uses a Kyushu University computational model to make a simulation to propagate the effect of various perturbations on satellites constellation in Tundra and Molniya orbits for 10 years. The computational Model solves the Gaussian planetary equations numerically under effect of orbit perturbations and gives a high accuracy for the interval of propagation for Tundra and Molniya satellites constellations. The results show that the effect of theses forces on different eccentricities 0.2~0.7 is varying, and the daily coverage hours for this satellites constellation increase and decrease according to the change in the argument of perigee or the right ascension of the ascending node. Hence, the over lapping between these satellites in the constellation will be affected. A non-coplanar maneuver done for the satellites that affected by perturbations to correct their positions in order to make a continuous coverage. .|
|7.||Me ́lissa Zemoura, Toshiya Hanada, Satomi Kawamoto, Removal Targets’ Classification: How Time Considerations Modify the Definition of the Index, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2017.05.046, 60, 6, 1163-1187, 2017.09, The growth of the near-Earth debris population since the beginning of human space activities is now a fact commonly admitted by space agencies worldwide. Numerous entities have warned about the danger that debris may have over time. Presently mitigation meth- ods such as imposing post-mission disposal time after launch will no longer be sufficient; remediation processes seem necessary to limit the increase. In particular, this phenomenon is attributed to the generation of fragments due to more and more on-orbit collisions. There- fore, investigations on indexes to select potential removal targets were recently conducted, considering solely objects implicated in a col- lision course. This study also looks at the multiple fragmentation factors, including time through the altitude at time of impact (due to the behaviour of debris re-entering with time).
The focal point is here to compare different criteria to select removal targets that enable scenarios in best adequacy with the future in question (long term, mid term or short term). Aware of the uncertainty of evolutionary models, this study also incorporates the simu- lation method as an impactful factor and tries to overcome the potential randomness of the results. Therefore, this paper presents a way to establish a selection criterion the most adequate for the time period focused on.
In order to solve this issue, a ‘‘double-check” method is proposed. First, an analytical evolutionary model simulates the environment over 100 years, through 100 Monte-Carlo runs. Then, among the initial population of year 2009, the objects supposed to be at the origin of the debris detected at a given time are tracked back in time into the simulations, using a collision-detecting program. The ‘‘given per- iod” above mentioned for the presence of debris is based on a future as such that 2029 be considered a short-term scenario, 2059 a mid- term scenario and 2109 a long-term scenario. This step produces three lists of targets for removal (one for each future), and simulations are run once again, through different scenarios involving the removal of particular listed targets in order to verify the appropriateness of the proposed scenarios. The analysis of the results is based both on the mean of the simulations and on the recurrence considering each run.
Three studies were conducted one for each term, and a fourth one completed the work by establishing comparison between short, mid and long-term periods. As a result, three main criteria could be established: the altitude of the objects, the number of targets necessary to remove, and the phenomenon of chain collisions. According to the future that was investigated, the most adequate criterion appeared to be different, consisting in the number of objects in the long-term analysis or the ranking position at short term (linked to the close-time consideration). As a main conclusion and further perspectives, it should be more efficient to consider the collision-probability and mass product together with the time-depending generation of fragments. This would help increasing the precision in the prediction of collision impacts.
Rather than pinpointing specified targets to be removed, the aim of this study is simply to understand the mechanisms at the origin of the population increase around the Earth. Also to demonstrate that a careful definition of selection criteria would enable to adopt a suitable removal process in the period of action or for the goal to be reached..
|8.||Koki Fujita, Naoyuki Ichimura, Toshiya Hanada, Simultaneous Detection of Multiple Debris via a Cascade of Numerical Evaluations and a Voting Scheme for Lines in an Image Sequence, Acta Astronautica, http://dx.doi.org/10.1016/j.actaastro.2016.10.032, 133, 416-422, 2017.04, This paper presents a novel method to simultaneously detect multiple trajectories of space debris in an observation image sequence to establish a reliable model for space debris environment in Geosynchronous Earth Orbit (GEO). The debris in GEO often appear faintly in image sequences due to the high altitude. A simple but steady way to detect such faint debris is to decrease a threshold value of binarization applied to an image sequence during preprocessing. However, a low threshold value of binarization leads to extracting a large number of objects other than debris that become obstacles to detect debris trajectories. In order to detect debris from binarized image frames with massive obstacles, this work proposes a method that utilizes a cascade of numerical evaluations and a voting scheme to evaluate characteristics of the line segments obtained by connecting two image objects in different image frames, which are the candidates of debris trajectories. In the proposed method, the line segments corresponding to objects other than debris are filtered out using three types of characteristics, namely displacement, direction, and continuity. First, the displacement and direction of debris motion are evaluated to remove irrelevant trajectories. Then, the continuity of the remaining line segments is checked to find debris by counting the number of image objects appearing on or close to the line segments. Since checking the continuity can be regarded as a voting scheme, the proposed cascade algorithm can take advantage of the properties of voting method such as the Hough transform, i.e., the robustness against heavy noises and clutters, and ability of detecting multiple trajectories simultaneously. The experimental tests using real image sequences obtained in a past observation campaign demonstrate the effectiveness of the proposed method..|
|9.||Masahiro Furumoto, Koki Fujita, Toshiya Hanada, Haruhisa Matsumoto, Yukihito Kitazawa, Orbital Plane Constraint Applicable for In-situ Measurement of Sub-millimeter-size Debris, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2016.12.036, 59, 6, 1599-1606, 2017.03, 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. First, this paper reviews the previous study on the nature of orbits on which debris may be detected through in-situ measurements proposed in the IDEA project. Second, this paper derives a simple equation that constrains the orbital plane on which debris is detected through in-situ measurements. Third, this paper also investigates the nature and sensitivity of this simple constraint equation to clear how frequently impacts have to be confirmed to reduce the measurement error. Finally, this paper introduces a torus model to describe the collision flux observed from the previous study approximately. This collision flux approximation agrees rather well with the observed collision flux. It is concluded, therefore, that the simple constraint equation and collision flux approximation introduced in this paper can replace the analytical method adopted by the previous study to conduct a further investigation more effectively..|
|10.||Hongru Chen, Yasuhiro Kawakatsu, Toshiya Hanada, Phasing Delta-V for the Transfer from a Sun-Earth Halo Orbit to the Moon, Acta Astronautica, http://dx.doi.org/10.1016/j.actaastro.2016.05.003, 127, 464-473, 2016.10, Inspired by successful extended missions such as the ISEE-3, an investigation for the extended mission that involves a lunar encounter following a Sun-Earth halo orbit mission is considered valuable. Most previous studies present the orbit-to-orbit transfers where the lunar phase is not considered. Intended for extended missions, the present work aims to solve for the minimum phasing ΔV for various initial lunar phases. Due to the solution multiplicity of the two-point boundary value problem, the general constrained optimization algorithm that does not identify multiple feasible solutions is shown to miss minima. A two-step differential corrector with a two-body Lambert solver is developed for identifying multiple solutions. The minimum ΔV associated with the short-way and long-way approaches can be recovered. It is acquired that the required ΔV to cover all initial lunar phases is around 45 m/s for the halo orbit with out-of-plane amplitude Az greater than 3.5×10^5 km, and 14 m/s for a small halo orbit with Az = 1×10^5 km. In addition, the paper discusses the phasing planning based on the ΔV result and the shift of lunar phase with halo orbit revolution..|
|11.||Hongru Chen, Yasuhiro Kawakatsu, Toshiya Hanada, Earth Escape from a Sun-Earth Halo Orbit Using the Unstable Manifold and Lunar Gravity Assists, Transactions of the Japan Society for Aeronautical and Space Sciences, 59, 5, 269-277, 2016.09, This paper investigates the Earth escape for spacecraft in a Sun-Earth halo orbit. The escape trajectory consists of first ejecting to the unstable manifold associated with the halo orbit, then coasting along the manifold until encountering the Moon, and finally performing lunar-gravity-assisted escape. The first intersection of the manifold tube and Moon’s orbit results in four intersection points. These four manifold-guided encounters have different relative velocities (v ̈) to the Moon; therefore, the corresponding lunar swingbys can result in different levels of characteristic energy (C3) with respect to the Earth. To further exploit these manifold-guided lunar encounters, subsequent swingbys utilizing solar perturbation are considered. A graphical method is introduced to reveal the theoretical upper limits of the C3 achieved by double and multiple swingbys. The numerically solved Sun-perturbed Moon-to-Moon transfers indicate that a second lunar swingby can efficiently increase C3. Compared to the direct low-energy escape along the manifold, applying a portion of the lunar swingbys before escape is shown to be more advantageous for deep-space mission design..|
|12.||Toshiya Hanada, Towards A Better Understanding of Space Debris Environment, International Journal of Aerospace System Engineering, http://dx.doi.org/10.20910/IJASE.2016.3.1.5, 3, 1, 5-9, 2016.06,
This paper briefly introduces efforts into space debris modeling towards a better understanding of space debris environment. Space debris modeling mainly consists of debris generation and orbit propagation. Debris generation can characterize and predict physical properties of fragments originating from explosions or collisions. Orbit propagation can characterize, track, and predict the behavior of individual or groups of space objects. Therefore, space debris modeling can build evolutionary models as essential tools to predict the stability of the future space debris populations. Space debris modeling is also useful and effective to improve the efficiency of measurements to be aware of the present environment.
|13.||Toshiya Hanada, Mitsuhiko Tasaki, Hiroaki Hamada, Akira Doi, Yukihito Kitazawa, Research and Development of Orbital Debris Removal using Low Density Material, IHI Engineering Review, 49, 1, 35-45, 2016.06, Currently, the danger due to debris in earth orbit is increasing. Furthermore, methods for the removal of such orbital debris have become the subject of attention. This paper proposes a concept for passive Orbital Debris Removal (ODR). In the passive ODR described in this research, a large area of polyimide foil is opened. Low earth orbit micro-debris decelerate due to their passing through the opened foil, and eventually reenter the atmosphere. In order to achieve efficient debris removal, as part of this research an unfolding mechanism has been invented that can open a large area of polyimide foil in low earth orbit. To demonstrate the effectiveness of this orbital debris removal concept, an event equivalent to the breaking up of a satellite by Chinese anti-satellite testing has been assumed. In order to give consideration to the perturbation of the orbital debris removal spacecraft, removal effectiveness was compared with regard to the direction of orbit injection, the effective cross sectional area, and orbit injection time as parameters..|
|14.||Makoto Tarawa, Toshifumi Yanagisawa, Hirohisa Kurosaki, Hiroshi Oda, Toshiya Hanada, Orbital objects detection algorithm using faint streaks, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2015.10.034, 57, 4, 929-937, 2016.02, This study proposes an algorithm to detect orbital objects that are small or moving at high apparent velocities from optical images by utilizing their faint streaks. In the conventional object-detection algorithm, a high signal-to-noise-ratio (e.g., 3 or more) is required, whereas in our proposed algorithm, the signals are summed along the streak direction to improve object-detection sensitivity. Lower signal-to-noise ratio objects were detected by applying the algorithm to a time series of images. The algorithm comprises the following steps: (1) image skewing, (2) image compression along the vertical axis, (3) detection and determination of streak position, (4) searching for object candidates using the time-series streak-position data, and (5) selecting the candidate with the best linearity and reliability. Our algorithm’s ability to detect streaks with signals weaker than the background noise was confirmed using images from the Australia Remote Observatory..|
|15.||Koki Fujita, Mitsuhiko Tasaki, Masahiro Furumoto, Toshiya Hanada, An orbit determination from debris impacts on measurement satellites, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2015.11.005, 57, 2, 620-626, 2016.01, This work proposes a method to determine orbital plane of a micron-sized space debris cloud utilizing their impacts on measurement satellites. Given that debris impacts occur on a line of intersection between debris and satellites orbital planes, a couple of debris orbital parameters, right ascension of the ascending node, inclination, and nodal regression rate can be determined by impact times and locations measured from more than two satellites in different earth orbits. This paper proves that unique solution for the debris orbital parameters is obtained from the measurement data, and derives a computational scheme to estimate them. The effectiveness of the proposed scheme is finally demonstrated by a simulation test, in which measurement data are obtained from a numerical simulation considering realistic debris’ and satellites’ orbits..|
|16.||Toshiya Hanada, Hideaki Hinagawa, Hongru Chen, Hiroaki Hamada, Shingo Ikemura, Attitude Motion Under Full Orbit Perturbations, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, http://doi.org/10.2322/tastj.13.45, 13, 45-50, 2015.09, This paper introduces an effort to precisely describe attitude motion under full orbit perturbations. To define the attitude of an Earth-orbiting spacecraft, this study introduces a reference frame being affected by orbit perturbations. Unlike the commonly adopted reference frame, the reference frame introduced here is fully perturbed, so that it rotates about not only the pitch axis, but also the yaw axis. To incorporate the mutual coupling effect between attitude motion and orbit motion, the method introduced considers the spacecraft as consisting of multiple facets and carefully models orbit perturbation-induced torque that varies the attitude. This paper focuses on the attitude dynamics of a small satellite with relatively low moments of inertia under full orbit perturbations, and provides some interesting results and the outcome from the method introduced. .|
|17.||Maki Nakamura, Yukihito Kitazawa, Haruhisa Matsumoto, Osamu Okudaira, Toshiya Hanada, Akira Sakurai, Kunihiro Funakoshi, Tetsuo Yasaka, Sunao Hasegawa, Masanori Kobayashi, Development of In-Situ Micro-Debris Measurement System, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2015.04.009, 56, 3, 436-448, 2015.08, The In-Situ Debris Environment Awareness System has been developed. The objective of the system is to measure small debris (between 100 μm and several cm) in orbit. The orbital distribution and the size distribution of the debris are not well understood. The size distribution is difficult to measure from the ground, although the size distribution is very important for the risk evaluation of the impact of debris on spacecraft. The in-situ measurement of the size distribution is useful for: 1) verification of meteoroid and debris environment models, 2) verification of meteoroid and debris environment evolution models, 3) real time detection of unexpected events, such as explosions and/or collisions on an orbit. This paper reports the development study of the in-situ debris measurement system and shows demonstration experiments and their results to describe the performance of the micro-debris sensor system. The sensor system for monitoring micro-debris with sizes ranging from 100 μm to a few mm must have a large detection area, while the constraints of space deployment require that these systems be low in mass, low in power, robust and have low telemetry requirements. For this reason, we have been developing a simple trans-film sensor. Thin and conductive stripes (copper) are formed with fine pitch (100 μm) on a thin film of nonconductive material (12.5-μm thick polyimide). A hypervelocity micro-particle impact is detected when one or more stripes are severed by perforation of the film. We designed a debris detector specialized for measuring the micro-debris size and collision rate. We then manufactured and calibrated the detector..|
|18.||Yuya Ariyoshi, Melissa Zemoura, Toshiya Hanada, Satomi Kawamoto, Effect of Small Satellites' Post-mission Disposal on Sustainable Space Utilization, Proceedings of the 7th International Conference on Recent Advances in Space Technologies, Intanbul, Turkey, June 16-19, 2015, http://dx.doi.org/10.1109/RAST.2015.7208446, 783-787, 2015.06, The number of small satellites as those that do not exceed 50kg is rapidly increasing in the low-Earth orbit region. Since the orbital debris mitigation guidelines released by United Nations, Inter-Agency Space Debris Coordination Committee and national space agency does not consider small satellites and typical large satellites separately, small satellites also should conduct post-mission disposal. However most small satellites are launched as piggyback satellites, affordable post-mission disposal of small satellites is different from that of typical large satellites, and this post-mission disposal of small satellites may cause the collisions to other satellites. For developers of small satellites, this paper introduces the effect of small satellites post-mission disposal on sustainable space utilization, which was presented by the authors in previous..|
|19.||Makoto Tagawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Yukihito Hanada, Toshiya Hanada, A Collaborative Observation Method Based on a Pair of Space-based Sensors and Ground Observatories for Small Debris in Low Earth Orbit, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, http://dx.doi.org/10.2322/tastj.12.Pr_27, 12, ists29, Pr_27-Pr_34, 2014.12, Unnecessary artificial objects, or so-called space debris, orbiting Earth contaminate the orbital environment and represent a serious problem for sustainable space development and use. One fundamental debris countermeas- ure is object tracking and cataloging. Such catalogs allow spacecraft mission risk assessment and the conducting of collision-avoidance maneuvers. However, the SpaceTrack object catalog released to the public is insufficient be- cause the catalog includes relatively large objects (> 10 cm), only. We propose using two space-based sensors to address this problem and analyze their observational and tracking capabilities. Initial results suggest that approxi- mately 4.2% of objects in low Earth orbit in size of 5-10 cm could be detected by space-based sensors. We also propose collaborative observations with a network of ground-based observatories. The space-based sensors are for detection and initial orbit determination, and the ground-based observatories are for catalog maintenance under collaboration with the space-based sensors. Initial orbit estimates from space-based sensors enable ground ob- servatories to employ the image stacking method. Simulated differences between predicted and true apparent posi- tions and motions indicate that it is possible to observe a target based on orbital data from space-based sensors..|
|20.||Yuya Aroyoshi, Toshiya Hanada, Satomi Kawamoto, Influence of Small Satellites' Post-mission Disposal with Enlarging Effective Cross-sectional Area, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, http://dx.doi.org/10.2322/tastj.12.Pr_21, 12, ists29, Pr_21-Pr_25, 2014.10, Developers of small satellites may think of enlarging their effective cross-sectional area to minimize the long-term presence in the low Earth orbit region. However, the enlargement of their effective cross-sectional area causes the temporal increase of cumulative probability of accidental collisions. This paper evaluates the influence of small satellites’ 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..|
|21.||Hongru Chen, Huixin Liu, Toshiya Hanada, Storm-time atmospheric density modeling using neural networks and its application in orbit propagation, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2013.11.052, 53, 3, 558-567, 2014.02, Upper atmospheric densities during geomagnetic storms are usually poorly estimated due to a lack of clear understanding of coupling mechanisms between the thermosphere and magnetosphere. Consequently, the orbit determination and propagation for low-Earth-orbit objects during geomagnetic storms have large uncertainties. Artificial neural networks are often used to identify nonlinear systems in the absence of rigorous theory. In the present study, an attempt has been made to model the storm-time atmospheric density using neural networks. Considering the debate over the representative of geomagnetic storm effect, i.e. the geomagnetic indices ap and Dst, three neu- ral network models (NNM) are developed with ap, Dst and a combination of ap and Dst respectively. The density data used for training the NNMs are derived from the measurements of the satellites CHAMP and GRACE. The NNMs are evaluated by looking at: (a) the mean residuals and the standard deviations with respect to the density data that are not used in training process, and (b) the accuracy of reconstructing the orbits of selected objects during storms employing each model. This empirical modeling technique and the compar- isons with the models NRLMSIS-00 and Jacchia-Bowman 2008 reveal (1) the capability of neural networks to model the relationship between solar and geomagnetic activities, and density variations; and (2) the merits and demerits of ap and Dst when it comes to char- acterizing density variations during storms..|
|22.||Hideaki Hinagawa, Hitoshi Yamaoka, Toshiya Hanada, Orbit determination by genetic algorithm and application to GEO observation, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2013.11.051, 53, 3, 532-542, 2014.02, This paper demonstrates an initial orbit determination method that solves the problem by a genetic algorithm using two well-known solutions for the Lambert’s problem: universal variable method and Battin method. This paper also suggests an intuitive error evaluation method in terms of rotational angle and orbit shape by separating orbit elements into two groups. As reference orbit, mean orbit ele- ments (original two-lines elements) and osculating orbit elements considering the J2 effect are adopted and compared. Our proposed orbit determination method has been tested with actual optical observations of a geosynchronous spacecraft. It should be noted that this dem- onstration of the orbit determination is limited to one test case. This observation was conducted during approximately 70 min on 2013/ 05/15 UT. Our method was compared with the orbit elements propagated by SGP4 using the TLE of the spacecraft. The result indicates that our proposed method had a slightly better performance on estimating orbit shape than Gauss’s methods and Escobal’s method by 120 km. In addition, the result of the rotational angle is closer to the osculating orbit elements than the mean orbit elements by 0.02°, which supports that the estimated orbit is valid..|
|23.||Toshiya Hanada, Orbital Debris Modeling and Applications at Kyushu University, Procedia Engineering, 10.1016/j.proeng.2013.12.040, 67, 404-411, 2013.12, The orbital debris modeling can build evolutionary models as essential tools to predict the current or future orbital debris populations, and also to discuss what and how to do for orbital debris mitigation and environmental remediation. The orbital debris modeling can also devise an effective search strategy applicable for breakup fragments in the geostationary region using ground-based optical sensors, and to evaluate the effectiveness of space-based measurements of objects not tracked from the ground, both to contribute to space situational awareness. Another application of the orbital debris modeling is to estimate attitude motion of space objects to be removed for environmental remediation. This paper briefly introduces efforts into orbital debris modeling and applications at Kyushu University..|
|24.||Makoto Tagawa, Toshifumi Yanagisawa, Haruhisa Matsumoto, Hirohisa Kurosaki, Hiroshi Oda, Toshiya Hanada, Yukihito Kitazawa, Capability Assessment of the Space-based Optical Measurement for LEO Debris, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol.11, 2013, pp.109-115, 11, 109-115, 2013.11, The presence of orbital debris is a potential risk for sustainable space development and its utilization for humankind. Prevention of large-scale spacecraft breakup events is a crucial part of countermeasures against orbital debris, and one of the key related technologies is the collision avoidance maneuver. Current observations are insufficient to track objects smaller than 10 cm, which are still large enough to cause catastrophic damage to primary spacecraft. The final goal of this study is to track debris 1 cm and larger in the low Earth orbit region. This paper proposes a space-based optical measurement system as a new promising solution. There are three points to be followed: 1) observation opportunity, 2) orbit determination accuracy and 3) tracking capability. As the first step, this paper focuses on assessing observation opportunity using a newly developed space-based observation simulator. This paper summarizes assessment results in terms of the number of passing objects, imaged objects, image moving velocity in pixels, apparent magnitude, observation occurrence frequency with respect to the observer’s true anomaly, and the relationship between the observation count and interval..|
|25.||Toshiya Hanada, Masahiko Uetsuhara, Toshifumi Yanagisawa, Yukihito Kitazawa, Effective Search Strategy Applicable for Breakup Fragments in the Geostationary Region, Journal of Spacecraft and Rockets, 10.2514/1.A32228, 50, 4, 802-806, 2013.07, This paper proposes to apply the space debris modeling techniques to devise an effective search strategy applicable for breakup fragments in the geostationary region. The space debris modeling techniques describe debris generation and orbit propagation to effectively conduct predictive analyses of space objects that include characterizing, tracking, and predicting the behavior of individual and groups of space objects. Therefore, the techniques can predict population of debris from a specific breakup event. The population prediction specifies effectively when, where, and how optical measurements using ground-based telescopes should be conducted. The space debris modeling techniques can also predict motion of debris in successive images taken with ground-based telescopes. The motion prediction specifies effectively and precisely how successive images of objects in the geostationary region should be processed. This paper also validates the proposed search strategy through actual observations, targeting the U.S. Titan IIIC Transtage explosion in the geostationary region.
|26.||Uetsuhara Masahiko, Yanagisawa Toshifumi, Kinoshita Daisuke, Hanada Toshiya, Kitazawa Yukihito, Observation campaign dedicated to 1968-081E fragments identification, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2013.02.008, 51, 12, 2207-2215, 2013.06, his paper proposes a comprehensive approach to associate origins of space objects newly discovered during optical surveys in the geostationary region with spacecraft breakup events. A recent study has shown that twelve breakup events would be occurred in the geostationary region. The proposed approach utilizes orbital debris modeling techniques to effectively conduct prediction, detection, and classification of breakup fragments. Two techniques are applied to get probable results for origin identifications. First, we select an observation point where a high detection rate for one breakup event among others can be expected. Second, we associate detected tracklets, which denotes the signals associated with a physical object, with the prediction results according to their angular velocities. The second technique investigates which breakup event a tracklet would belong to, and its probability by using the k-nearest neighbor (k-NN) algorithm.
In this paper we conduct optical observations of breakup fragments to verify the proposed approach. We selected a well-known breakup event of the rocket body US Titan 3C Transtage (1968-081E) as the primary observation target, and then we conduct optical observations by campaign between two sensors in Taiwan and one sensor in Japan. While three nights observations, we detect 96 trac- klets that are uncorrelated with the Space Surveillance Network catalogue at the observation epochs, and finally 50 tracklets among them are associated with the breakup event of 1968-081E..
|27.||Yuya Ariyoshi, Toshiya Hanada, Satomi Kawamoto, Are Small Satellites Hazardous in Comparison to Large Spacecraft?, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol.11, 2013, pp.1-5, 11, 1-5, 2013.04, The Space Debris Mitigation Guidelines of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space consist of seven guidelines to be considered for the mission planning, design, manufacturing and operational (launch, mission and disposal) phases of spacecraft and launch vehicle orbital stages. In order to compare small satellites with large satellites in terms of impact on the orbital debris environment, this paper focuses on guideline 3 in the mitigation guidelines, which limit the probability of accidental collision in orbit. The probability of accidental collision is a function of the effective cross-sectional area. Large satellites have a larger effective cross-sectional area in comparison to small satellites, so that large satellites specify a higher probability of accidental collision than small satellites do. The number of fragments to be generated by a collision is a function of mass. Therefore, in the comparison to small satellites, large satellites also generate more fragments and add them to the environment..|
|28.||Toshiya Hanada, Yuya Ariyoshi, Masahiko Uetsuhara, Makoto Tagawa, Hongru Chen, Yuki Tsutsumi, Akira Doi, Satomi Kawamoto, Toshifumi Yanagisawa, Kozue Hashimoto4, Aritsune Kawabe, and Yukihito Kitazawa, Orbital Debris Modeling and Applications at Kyushu University, Journal of Space Technology and Science, 26, 2, 28–47, 2012.11, This paper briefly introduces efforts made at Kyushu University in the area of orbital debris modeling and applications. The orbital debris modeling, which describes debris generation and orbit propagation, enables us to build orbital debris evolutionary models as essential tools to predict the future orbital debris population, and as applications to discuss what and how to do for orbital debris mitigation and remediation. The orbital debris modeling also enables us to 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. Ultimately, this paper includes atmospheric density modeling necessary for orbital decay and re-entry analyses, and space tether modeling to assess risks of using electrodynamic tethers for removing hazardous objects from the low Earth orbit region. .|
|29.||Hanada Toshiya, Strategy to Search Fragments from Breakups in GEO, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2012.01.012, 49, 7, 1151-1159, 2012.04, This paper proposes a strategy to search fragments from breakups in the Geosynchronous Earth Orbit (GEO) region based upon population prediction and motion prediction by means of ground-based optical observations. Breakup fragments have uncertainties in the states such as their position and motion, or even in their existence. Population prediction and motion prediction resolve those uncertainties. Population prediction evaluates the time-averaged distribution of fragments, whose position at a given time is unknown, in the celestial sphere. Motion prediction evaluates the expected motion of fragments appeared in image series acquired by a telescope's CCD camera. This paper logically describes procedures of the search strategy, and provides mathematical expressions of population pre- diction and motion prediction. This paper also validates the search strategy via actual observations, in which a confirmed breakup in the GEO region is selected as a target. It is concluded that the proposed strategy is valid even for searching uncataloged fragments from breakups in the GEO region..|
|30.||T. Narumi, Y. Akahoshi, J. Murakami, T. Hanada, Numerical Simulation of Spacecraft Fragmentation for Hypervelocity Impact, Proceedings of the 11th Hypervelocity Impact Symposium, Freibrug, Germany, April 11-15, 2010, pp.442-452, 2011.10.|
|31.||T. Hanada, J. Murakami, Y. Tsuruda, J.-C., Liou, Microsatellite Impact Fragmentation, Proceedings of the 11th Hypervelocity Impact Symposium, Freibrug, Germany, April 11-15, 2010, pp.465-476, 2011.10, This paper summarizes recent microsatellite impact tests conducted under contract with the NASA Orbital Debris Program Office. The motivation for the impact tests is twofold. First, as new satellite materials continue to be developed, there is a need for impact tests on satellites made of modern materials to better characterize the outcome of future on-orbit satellite fragmentation. Second, it is necessary to extend tests to different velocity regimes to cover potential low-velocity collisions in the geosynchronous region. To date, seven impact tests have been carried out. All microsatellites were totally fragmented and generated more than 1000 fragments each. Fragments down to about 2 mm in size were collected, measured, and analyzed. Main summary of this paper includes size, mass, area-to-mass ratio, and shape distributions of fragments generated from each test and how they vary with size, material type, and impact parameters. .|
|32.||Hiroshi Hirayama, Ieyoung Kim, Toshiya Hanada, Survivability of Tether throughout Deorbiting, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology Japan, Vol. 8, No.ists27 (ISTS Special Issue: Selected papers from the 27th International Symposium on Space Technology and Science), pp.Pr_2_25-Pr_2_30, 2011.09.|
|33.||Toshiya Hanada, Jer-Chyi Liou, Theoretical and Empirical Analysis of the Average Cross-sectional Areas of Breakup Fragments, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2011.01.008, 47, 10, 1480-1489, 2011.05.|
|34.||K. Fujita , T. Hanada, Y. Kitazawa, A. Kawabe, A Debris Image Tracking Using Optical Flow Algorithm, Advances in Space Research, http://dx.doi.org/10.1016/j.asr.2011.12.010, 49, 5, 1007-1018, 2011.03, This study proposes a motion detection and object tracking technique for GEO debris in a sequence of images. A couple of techniques (called the "stacking method" and "line-identifying technique") were recently proposed to address the same problem. Although these techniques are effective at detecting the debris position and motion in the image sequences, there are some issues concerned with computational load and assumed debris motion. This study derives a method to estimate motion vectors of objects in image sequence and finally detect the debris locations by using a computer vision technique called an optical flow algorithm. The new method detects these parameters in low computational time in a serial manner, which implies that it has an advantage to track not only linear but also nonlinear motion of GEO debris more easily than the previous methods. The feasibility of the proposed methods is validated using real and synthesized image sequences which contain some typical debris motions..|
|35.||Kazuaki Maniwa, Toshiya Hanada, Satomi Kawamoto, Benefits of Active Debris Removal on the LEO Debris Population, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology Japan, Vol. 8, No.ists27 (ISTS Special Issue: Selected papers from the 27th International Symposium on Space Technology and Science), pp.Pr_2_7-Pr_2_12, 2011.03.|
|36.||Junko Murakami, Toshiya Hanada, Jer-Chyi Liou, Microsatellite Impact Tests to Investigate the Outcome of Satellite Fragmentation, Journal of Spacecraft and Rockets, 48, 1, 208-212, 2011.02.|
|37.||Ieyoung Kim, Hiroshi Hirayama, Toshiya Hanada, Practical Guidelines for ElectroDynamic Tethers to Survive from Orbital Debris Impacts, Advances in Space Research, 45, 10, 1292-1300, 2010.05.|
|38.||Satomi Kawamoto, Yuki Kobayashi, Yasushi Ohkawa, Shoji Kitamura, Shin-Ichiro Nishida, Chiharu Kikkawa, Atsushi Yanagida, Susumu Toda, Yoshiki Yamagiwa, Mengu Cho, Toshiya Hanada, A Test Flight Experiment of Electrodynamic Tether Using a Small Satellite: As the First Step for Debris Removal, Journal of Space Technology and Science, Vol.24, No.2, pp.36-44, 2009.09.|
|39.||Toshiya Hanada, Yuya Ariyoshi, Kazuki Miyazaki, Kazuaki Maniwa, Junko Murakami, and Satomi Kawamoto, Orbital Debris Modeling at Kyushu University, Journal of Space Technology and Science, Vol.24, No.2, pp.23-35. , 2009.09.|
|40.||Toshiya Hanada, Jer-Chyi Liou, Paula Krisko, Takashi Nakajima, For Better Calculation of the Average Cross-Sectional Area of Breakup Fragments, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology Japan, Vol. 7, No.ists26 (ISTS Special Issue: Selected papers from the 26th International Symposium on Space Technology and Science), pp.Pr_2_25-Pr_2_30, 2009.09.|
|41.||Toshiya Hanada, Jer-Chyi Liou, Takashi Nakajima, Eugene Stansbery, Outcome of Recent Satellite Impact Experiments, Advances in Space Research, Vol.44, No.5, pp.558-576, 2009.09.|
|42.||Yoshihiro Tsuruda, Toshiya Hanada, Jozef C. van der Ha, QSAT: A Low-Cost Design for 50 kg Class Piggyback Satellite, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology Japan, Vol. 7, No.ists26 (ISTS Special Issue: Selected papers from the 26th International Symposium on Space Technology and Science), pp.Tf_7-Tf_12, 2009.08.|
|43.||Yoshihiro Tsuruda, Akiko Fujimoto, Naomi Kurahara, Toshiya Hanada, Kiyohumi Yumoto, Mengu Cho, QSAT: the Satellite for Polar Plasma Observation, International Journal of Earth, Moon, and Planets, Vol.104, Nos.1-4, 2009, pp.349-360, 2009.04.|
|44.||Carmen Pardini, Toshiya Hanada, Paula H. Krisko, Benefits and Risks of Using Electrodynamic Tethers to De-Orbit Spacecraft, Acta Astronautica, Vol.64, Nos.5-6, 2009, pp.571-588, 2009.04.|
|45.||Kosuke Sakuraba, Yoshihiro Tsuruda, Toshiya Hanada, Jer-Chyi Liou, Yasuhiro Akahoshi, Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model, International Journal of Impact Engineering, Vol.35, No.12, pp.1567-1572, 2008.12.|
|46.||Hitoshi Ikeda, Toshiya Hanada, Tetsuo Yasaka, Searching for Lost Fragments in GEO, Acta Astronautica, Vol.63, Nos.11-12, pp.1312-1317, 2008.12.|
|47.||Toshiya Hanada, Jer-Chyi Liou, Comparison of Fragments Created by Low- and Hyper-velocity Impacts, Advances in Space Research, Vol.41, No.7, 2008, pp.1132-1137, 2008.03.|
|48.||Tamiki Ueno, Akiko Fujimoto, Kiyuhumi Yumoto, Keisuke Ushijima, Hideki Mizunaga, Toshiya Hanada, Measurement of QSAT Residual Magnetism, Memoirs of the Faculty of Sciences, Kyushu University (Series D Earth and Planetary Sciences), Vol.XXXII, No.1, 2008, pp.7-23, 2008.02.|
|49.||Hiroshi Hirayama, Atsushi Oishi, Toshiya Hanada, Tetsuo Yasaka, Stochastic Analysis of Survivability of Double Tether, Acta Astronautica, Vol.62, No.1, 2008, pp.54-58, 2008.01.|
|50.||Tomohiro Narumi, Toshiya Hanada, New Orbit Propagator to Be Used in Orbital Debris Evolutionary Models, Memoirs of the Faculty of Engineering, Kyushu University, Vol.67, No.4, 2007, pp.235-254, 2007.12.|
|51.||Carmen Pardini, Toshiya Hanada, Paula H. Krisko, Luciano Anselmo, Hiroshi Hirayama, Are De-Orbiting Missions Possible Using Electrodynamic Tethers? Task Review from the Space Debris Perspective, Acta Astronautica, Vol.60, Nos.10-11, 2007, pp.916-929, 2007.05.|
|52.||Toshiya Hanada, Tetsuo Yasaka, Orbital Evolution of Cloud Particles from Explosions of Geosynchronous Objects, Journal of Spacecraft and Rockets, 10.2514/1.11998, 42, 6, 1070-1076, Vol.42, No.6, pp.1070-1076, 2005.11.|
|53.||Toshiya Hanada, Tetsuo Yasaka, Hidehiro Hata, Yasuhiro Akahoshi, Using NASA Standard Breakup Model to Describe Low-velocity Impact on Spacecraft, Journal of Spacecraft and Rockets, 10.2514/1.11600, 42, 5, 859-864, Vol.42, No.5, pp.859-864, 2005.09.|
|54.||Hiroshi Hirayama, Toshiya Hanada, Tetsuo Yasaka, In-Situ Debris Measurements in MEO/HEO Using Onboard Spacecraft Inspection System, Advances in Space Research, 10.1016/j.asr.2003.11.018, 34, 5, 951-956, 2004.12.|
|55.||Toshiya Hanada, Developing A Low-Velocity Collision Based on the NASA Standard Breakup Model 1998 Revision, International Journal of Space Debris, 2, 4, 233-248, 2004.12.|
|56.||Hidehiro Hata, Yasuo Kurakazu, Yasuhiro Akahoshi, Toshiya Hanada, Tetsuo Yasaka, Shoji Harada, Model Improvement for Low-velocity Collision Possible in Space, International Journal of Impact Engineering, 10.1016/j.ijimpeng.2003.09.028, 29, 10, 323-332, 2003.12.|
|57.||Modeling the Orbital Debris Environment.|
|58.||Consequences of Continued Grwoth in the GEO and GEO Disposal Orbital Regimes.|
|59.||Tetsuo Yasaka, Orbital Debris Environment Model in the Geosynchronous Region, Journal of Spacecraft and Rockets, 10.2514/2.3786, 39, 1, 92-98, Vol.39, N0.1, pp.92-98, 2002.01.|
|60.||T.J. Hebert, J.L. Africano, E.G. Stansbery, M.J. Matney, D.T. Hall, J.F. Pawlowski, P.D. Anz-Meador, K.S. Jarvis, N. Hartsough, M.K. Mulrooney, Optical Observations of the Orbital Debris Environment at NASA, Advances in Space Researches, 10.1016/S0273-1177(01)00398-2, 28, 9, 1283-1290, Vol.28, No.9, pp.1283-1290, 2001.12.|
|61.||Tetsuo Yasaka, Toshiya Hanada, Hiroshi Hirayama, Low Velocity Projectile Impact on Spacecraft, Acta Astronautica, 10.1016/S0094-5765(00)00127-2, 47, 10, 763-770, 2000.11.|
|62.||Tetsuo Yasaka, Toshiya Hanada, Hiroshi Hirayama, GEO Debris Environment: A Model to Forecast The Next 100 Years, Advances in Space Researches, 10.1016/S0273-1177(99)00004-6, 23, 1, 191-199, 1999.01.|
|63.||Tetsuo Yasaka, Toshiya Hanada, GEO Debris Accumulation Model Viewed from Low Speed Impact Tests, Space Forum, 1, 1-4, 151-160, 1996.12.|
|64.||Toshiya Hanada, Masanobu Namba, Unsteady Aerodynamic Analysis of Supersonic Through-Flow Fan with Vibrating Blades under Non-Zero Mean Loading, Journal of Sound and Vibration, 10.1006/jsvi.1996.0390, 194, 5, 709-750, 1996.08.|
|65.||花田俊也，難波昌伸, Unsteady Lifting Surface Theory for Supersonic Through-Flow Fan, Japan Society of Mechanical Engineers International Journal (Series B), 37, 4, 760-768, 1994.11.|
|66.||Toshiya Hanada, Masanobu Namba, Double Linearization Theory for Supersonic Through-Flow Fan, Memoirs of the Faculty of Engineering, Kyushu University, 53, 3, 151-179, 1993.09.|