TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN
Online ISSN : 1884-0485
Advance online publication
Showing 1-43 articles out of 43 articles from Advance online publication
  • Masanori KANAMARU, Sho SASAKI
    Article ID: 17.270
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    A constraint of rubble-pile interior is an essential issue for better understanding of its formation scenario such as catastrophic disruption and reconfiguration. A goal of this study is to demonstrate a method to constrain unknown density distribution within a small solar system body. We calculated the gravity field on the surface of asteroid 25143 Itokawa using a 3D shape model. We assumed density inhomogeneity between two lobes of Itokawa; “Head" and “Body" of the sea-otter-like shape. Then, we estimated interior density distribution of Itokawa as an index of the gravity potential variance (and surface slope average). This study implied that the Head of Itokawa had a more monolithic structure of significantly higher density than the remaining Body part. The density of the Head was evaluated as ~ 2,750 kg/m3, which is much higher than the Itokawa’s mean density of 1,950 kg/m3. Such a dramatic density anomaly corresponds to a great offset between the center-of-mass (COM) and the center-of-figure (COF) by ~ 16m. This result implies interior density inhomogeneity within a rubble-pile asteroid.

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  • Yoshinori NAKAYAMA
    Article ID: 17.276
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Because thruster performance and the durability of electric propulsion differ between ground tests and space operations, it is important to evaluate the rarefied propellant flow within the vacuum test facility. Through numerical analysis for rarefied propellant flow within a vacuum chamber, results confirmed that vacuum pump arrangement and thruster location influenced the propellant flow, and that a conical target installation is somewhat useful. The average pressure within the chamber is proportional to the average distance between the thruster and the pumps.

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  • Yosuke MEICHIN, Masafumi TANAKA
    Article ID: 17.282
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Most of solid propellants have difficulty in controlling magnitude of their thrust or stopping their operation arbitrarily. Some solid propellants show a unique property of self-quenching in intermediate pressure range. This property could be utilized for the realization of actively controlled solid propellant rocket motor. However, little is known about the mechanism of this self-quenching phenomenon. In this paper, a simulation model of this phenomenon is developed and the simulation results are compared with the experiment results to determine the mechanism of this self-quenching phenomenon. The simulation results are in good agreement with the experiment results by assuming self-quenching phenomenon has stochastic nature and by selecting proper parameters.

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  • Koki KITAGAWA, Shinichiro TOKUDOME, Keiichi HORI, Haruhito TANNO, Nobu ...
    Article ID: 17.289
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The development of enhanced propulsion system for the next Epsilon rocket was progressed. The development of Enhanced Epsilon is mainly the renewal of the second stage, and also includes each subsystem's improvement. The second stage motor M-35 was newly designed and manufactured. In order to verify the design, the static firing test of the second motor M-35 under the condition of vacuum ambient was conducted in 2015. The JAXA successfully launched the first Enhanced Epsilon launch vehicle. All solid propulsion systems for the Enhanced Epsilon launch vehicle showed a very good behavior during the flight

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  • Hiroki UTO, Toshinori KUWAHARA, Tomoyuki HONDA
    Article ID: 17.295
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Nakashimada Engineering Works, Ltd. and Tohoku University have developed a 1U-size CubeSat “FREEDOM”. The mission of FREEDOM is to demonstrate a thin film deployment mechanism called the De-Orbit Mechanism (DOM) for space debris prevention, and includes deployment of the thin film, early de-orbiting, and tracking of its orbit transition. FREEDOM was released into low Earth orbit from the International Space Station using the robotic arm of the Japanese Experiment Module “Kibo” on January 16, 2017. The initial altitude of FREEDOM was approximately 410 km. The transition of the orbit of FREEDOM was monitored by obtaining the publicly available two line elements. FREEDOM fell below an altitude of 250 km on February 6, 2017 and is considered to have re-entered into the Earth atmosphere approximately one day later. FREEDOM stayed in orbit approximately 22 days. This result agrees with the numerical estimates and proves that FREEDOM succeeded in the deployment of the film and early de-orbiting.

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  • Susumu HASEGAWA, Takeshi KANDA
    Article ID: 17.301
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Numerical simulation of aerodynamics around the spaceplane was conducted in the equivalent condition to the transonic wind tunnel tests at ISAS/JAXA. Numerical results reproduced experimental results, and they are useful to discuss the experimental results. Two configurations, namely, the experimental model and the original model were investigated. In all Mach numbers, drag coefficient of the experimental model was larger than that of the original model. Especially the wing and the tail made large drag. The different cross section of the wing and the tail caused the larger drag in the experimental model.

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  • Ralph KAHLE, Sofya SPIRIDONOVA, Michael KIRSCHNER
    Article ID: 17.308
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The reference orbit implemented for the active TerraSAR-X mission works remarkably well for orbit control purposes, but an unexpected secular drift in the along-track separation between satellite and reference orbits has built up to a 60 s flight-time offset within 10 years of operation. The scope of this work is to understand the origin of the drift and to eliminate the effect for DLR's future repeat ground-track missions EnMAP and Tandem-L. The improved process of reference orbit generation is discussed and the underlying relations for the suggested inclination adjustment are derived. The improved process is successfully validated by means of 1-year numerical orbit control simulation. The presented process is generic and can be applied to any repeat-ground track mission.

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  • Ryota FUSE, Shinsuke ABE, Masahisa YANAGISAWA, Ryu FUNASE, Hajime YANO
    Article ID: 17.315
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    When a meteoroid impacts the Moon at several tens of km/s, a brilliant flash, referred to as a lunar impact flash, can be observed at the point of impact by ground-based telescope. Lunar impact flashes observed from the ground are biased due to atmospheric extinction, background illumination of earthshine, and short observation windows, typically a few hours per day during a period of approximately 10 days. NASA’s meteoroid impact program took 10 years to detect 400 lunar impact flashes. EQUULEUS will demonstrate low-energy trajectory control techniques, such as multiple lunar flybys, proposed by the University of Tokyo and JAXA, within the Earth-Moon region. The spacecraft will be launched by NASA-SLS in 2019. The DELPHINUS camera system will be placed onboard EQUULEUS to observe lunar impact flashes while the spacecraft stays in halo orbit around an Earth-Moon L2 point. Thus, the lunar distance from the spacecraft is approximately one tenth that from ground-based observation. We estimate that DELPHINUS will detect 1,607, 2,699, and 4,534 lunar impact flashes during its six-month mission phase by assuming the limiting magnitude of its camera to be the 4.5th, 5.0th, and 5.5th magnitudes, respectively. The present study describes the DELPHINUS camera system and the first method for space-based observation of lunar impact flashes.

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  • Tobias TRAUDT, Stefan SCHLECHTRIEM
    Article ID: 17.321
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    A thermal lattice-Boltzmann model of a van der Waals gas was used to check its applicability to specific challenges in the numerical simulation of transient cryogenic two-phase flow in rocket engine feed systems. Three test cases were chosen to prove the model is capable of capturing the underlying physics. Overall correct representation of incompressible flow should be demonstrated by a lid-driven cavity. The capability of the model to handle shocks and supersonic flow is shown in a shock tube configuration. The last test case was chosen in order to show instantaneous evaporation by the formation of a single vapour bubble at a heated surface.

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  • Joshua CRITCHLEY-MARROWS, Xiaofeng WU
    Article ID: 17.327
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    For all common satellite attitude determination sensors, star trackers provide the most accurate measurement. However, these devices can be both large and expensive, and for some CubeSat applications it would not be suitable. Star trackers have in the past been successfully made for CubeSats. This paper investigates star tracker algorithms, implemented with a smartphone, so it may be used for testing attitude determination on a CubeSat. By testing through a proposed implementation, star centroids should be found by the moment method, stars should be identified by planar triangles, and QUEST should be used for attitude estimation. Smeared star images should be avoided and blurred images provide greater accuracy. Using these techniques, a star tracker using a smartphone may be constructed for attitude determination testing and software development, applied in the lost-in-space situation. This may be applied to QKD CubeSats, which require an attitude precision below 0.01°.

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  • Kenichi HIRAI, Akiko NAKAZATO, Hayato YANO, Kenichi KAWAZONE, Jun KOYA ...
    Article ID: 17.333
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Ablative performance of High-density carbon phenolic (HD-CFRP) is investigated by exposing to an extremely cold temperature of -160 degree Celsius, followed by rapid heating conditions ranging from 5.5 to 12.1 MW/m2 of JAXA/ISAS arc jet tests to identify the thermal integrity of the material as a future re-entry capsule heat shield material with demanding system requirements, In this paper, we introduce our activities and the outcomes by the investigation.

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  • Jun YOSHIDA, Nobuo KENMOCHI, Hiroshi SUGITA, Yoshifumi NODOMI, Shingo ...
    Article ID: 17.339
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Pointing mechanism installed on GOSAT/TANSO-FTS is one of the most essential techniques to realize optimal observation patterns on the earth and a long-term operation period. In orbit, the continuous increase of angular rate sensor cable torque was occurred, and this induced the limited pointing angle operation for the along track direction. In this paper, we report reproducing experimental results for the degradation of the pointing mechanism in orbit.

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  • Akihiro SATO, Madoka NAKAJIMA, Naohiko KOHTAKE
    Article ID: 17.344
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Taking action for evacuation immediately is the most important and effective measure when tsunami attacks in the aftermath of a large earthquake. In this paper, a concept of delivering the least amount of emergency warning information and location based information possible is presented with a design of indoor/outdoor seamless positioning and emergency warning system that uses GNSS-based signals. This system includes an indoor positioning system equipped with a positioning method with GNSS-based signals and broadcasts a small volume of data including emergency warning information indoor and outdoor as well as the navigation message. A facility with large indoor space in coastal areas has GNSS antenna, receives and relays the emergency warning message from GNSS to transmitters of indoor positioning system via local area network. The system also has a function to provide indoor evacuation control information from building security room. The data communication speed of indoor signals compatible with GNSS is low as well as GNSS signals. Although the available data volume for emergency warning information is limited, we have confirmed the system is able to provide marginal information on an actual case of indoor positioning system, the indoor messaging system (IMES).

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  • Hikaru ISOCHI, Hikaru OTABE, Tsutomu UEMATSU, Nobuji KATO, Keiichi HOR ...
    Article ID: 17.350
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The performance improvement and cost reduction of solid rocket propellants has been a major concern of the solid rocket community. The use of low melting temperature thermoplastic as a fuel binder is one of the solutions. This paper presents a molding method of LTPs (Low Melting Temperature Thermoplastic Propellant) and the result of tests with a new mixing device.

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  • Kenichi HIRAI, Akiko NAKAZATO, Jun KOYANAGI, Kazuhiko YAMADA
    Article ID: 17.354
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Mid-density carbon phenolic (MD-CFRP) is a promising candidate for heat shield materials for future re-entry capsules because it could provide us with much lighter heat shields than the conventional high-density CFRP and also it could be possible to be free of delamination even if it was heated in the cross-ply direction, Here in this paper, we introduce our in-house R&D activities on the MD-CFRP which is currently underway.

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  • Kenji KITAMURA, Katsuhiko YAMADA, Takeya SHIMA
    Article ID: 17.363
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This study considers the minimum time orbit-raising problem of geostationary spacecraft with low-propulsion thrusters. This problem is equivalent to determining an appropriate thrust direction during orbit raising. This study proposes a closedloop thruster steering law that determines the thrust direction based on the optimal feedback gains and control errors of each orbital element. The feedback gains of the steering law are assumed to be the functions of orbital elements and are optimized by a meta-heuristic method. The orbital semi-major axis, eccentricity, and inclination are considered as independent variables for expressing the gains. Numerical simulations show that whichever orbital elements is selected as an independent variable, the same performances are obtained. Therefore, regardless of the initial orbital elements, by selecting the independent variable appropriately, the proposed method can always solve the minimum time orbit-transfer problem.

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  • Daiki HIGASHIYAMA, Katsuhiko YAMADA, Yasuhiro SHOJI
    Article ID: 17.371
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper considers a rest-to-rest spacecraft attitude maneuver using two variable-speed control moment gyros. Two methods are used to derive angular momentum and gimbal angles over time subject to physical constraints. The first is an analytical method using variational calculus: from the analytical solution the dynamic characteristics of the attitude maneuver are easily understood and feasible trajectories are derived. The second is a numerical method which uses a Chebyshev pseudospectral method. The maneuvering time is minimized by the numerical method. In this second method, it is difficult to obtain a solution without appropriate initial values. However, a solution can be derived by using an analytical solution as initial values. The analytical and numerical methods are executed in all directions of the attitude maneuver, thus validating the effectiveness of the successful completion of the intended maneuver. Finally, ground experiments are conducted using the optimal trajectories obtained by the numerical method.

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  • Kiyokazu KOGA, Haruka UENO
    Article ID: 17.380
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Satellite charging causes anomalies and its effect still accounts for the main part of failure that occurs in the space environment. It is important to measure plasma particles in order to elucidate the interactions between such charging and the space environment. For this purpose, the Avalanche PhotoDiode (APD) type sensor is used to minimize instrument size and weight. The APD basically measures photons, but can also be used to measure electrons. This paper reports the performance of the APD sensor, and presents the instrument design results for flight investigation.

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  • Kazumasa SASAHARA, Yoshiyuki UWAMINO, Sunao HASEGAWA, Kanjuro MAKIHARA
    Article ID: 17.383
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Space debris poses a serious threat and the problem must be solved. Space debris should be removed to maintain the space environment. One of the techniques to remove it is an electrodynamic tether system (EDTS). To improve the toughness of the tether used in EDTS, this study investigated the tether shape of a hollow cylinder instead of the conventional solid cylinder. When the mass and length of a hollow tether are the same as those of the solid tether, the hollow cylindrical tether has a larger diameter. Thus, the toughness against small debris collisions will be improved. To investigate the damage to the hollow tether following a debris collision, hypervelocity impact experiments were performed using a two-stage light-gas gun. Through the impact experiments, the relationship between the damage to the hollow tether and the impact condition of the debris was revealed. It was confirmed that when the impact angle increased the damage area increased as well. The experiments validated that a hollow tether is superior to a solid tether in terms of resistance to debris collisions. In addition, the importance of considering the influence of the impact angle was shown by an evaluation of the lifetime of the hollow tether.

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  • Makoto WAKABAYASHI, Taku TAKADA, Kazumasa IMAI, Yoshihiro KAJIMURA, Ju ...
    Article ID: 17.392
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper describes the “2016 KOSEN Space Camp,” which is a introductory education program on space technology for students enrolled at the various KOSEN colleges of technology in Japan. The camp was conducted twice, the first time on September 3–6, 2015 and the second time on September 1–4, 2016 at the Marine Park Niihama. Approximately 40 students and more than 10 teachers participated in the camp on each of the two occasions when it was held. The activities in the camp included a lecture by an eminent scientist; the study of basic rocket theory; model rocket experiments; and the development, analysis, and presentation of CanSat satellite model experiments. This unique education program provided by aerospace scientists and engineers is a KOSEN concept and product.

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  • Naoko OGAWA, Yuichi TSUDA, Yuto TAKEI, Hiroka INOUE, Shota TAKAHASHI, ...
    Article ID: 17.398
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The Martian Moons eXploration (MMX) mission is now under study by the Japan Aerospace Exploration Agency (JAXA). Its scope includes the world's first landing on one of the Martian moons, collecting samples from the surface, and returning to Earth. This paper describes the orbit design for MMX. Nominal and backup trajectories for launch in 2024 and 2026 are discussed. The Mars orbit insertion (MOI) sequence using 3-impulse maneuvers is introduced. A new scheme, the robust MOI, is also proposed as a contingency to enhance the robustness of the mission sequence. A method to design a robust MOI trajectory and examples are presented.

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  • Shota TAKAHASHI, Naoko OGAWA, Yasuhiro KAWAKATSU
    Article ID: 17.404
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Failure of the orbit insertion maneuver has a significant impact on the entire mission, for the trajectory of a spacecraft is largely deflected by swing-by. The risk can be reduced by targeting a point on the B-plane where the spacecraft reaches the free-return (FR) trajectory with the target body in the case of insertion failure. The backup orbit must also satisfy conditions suitable for the mission. We investigated the type of orbit insertion that is both robust to failure and reasonable for the mission requirements. We call this method FR ensured orbit insertion. Among various failure modes of the orbit insertion maneuver, we focus on the complete maneuver failure. The impact parameters on the B-plane to achieve the orbit insertion are formulated based on the geometry of velocity vectors at swing-by. The necessary deflection angle αFR at swing-by must be smaller than the possible maximum deflection angle αmax for the target body. When we introduce proper scaling factors, the relation of αmax and αFR is characterized by a single parameter λ. Using polar orbit insertion as an example, maps which show the reachability of FR trajectory after the insertion failure for each approaching condition are presented. The derived maps can be used as a tool to assess the applicability of the method in the mission design. Finally, as an application to practical mission design, we demonstrate the use of FR ensured orbit insertion in JAXA’s MMX mission.

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  • Yohsuke NAMBU, Masashi MIURA, Ryosuke YOSHIZAWA, Toshishige HAGIHARA, ...
    Article ID: 17.412
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Recently, products and service have become more and more complex, and have been desired to be released rapidly. Therefore, not only national projects but also small team projects have become to need system thinking and system engineering (SE) process. However, it is difficult to introduce conventional SE processes into the small team project such as university-led nanosatellite projects, because the SE process is far different from their present process. This research aims to develop a web application including its methodology to realize open model-based collaboration (Open MBC), which is a framework to support efficient and collaborative development of complex systems. This paper describes the concept of Open MBC, concrete processes, and the features of the web application. Open MBC is a fusion of a system model, a collaborative work flow, and an open engineering platform. The system model graphically represents the relationships among elements. The collaborative work flow provides efficient collaboration and further functions as a platform for promoting the re-discovery and reuse of knowledge. Open MBC holds communication among engineers in great account. It provides communication on system models, same as GitHub provides communication on codes. We believe that feedbacks and lessens learned from experienced engineers should improve low motivation of young engineers. Our application is called BALUS (browser-based assisted library universal system design application), and runs on a web browser, such as Google Chrome. Users are not requested to install software on their own computer, and can use the application even with a smart phone or a tablet. We conducted design education programs using BALUS. It revealed that BALUS was useful for the MBSE education and activities of students and engineers of small and medium-sized enterprises where no SE professionals are employed. The result of questionnaire from students showed that the feature to create requirement diagrams rapidly and concurrently helped beginners to learn “System Thinking.”

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  • Eri SHIMANE, Shuichi MATSUMOTO, Takafumi MORIGUCHI, Yuzo IWAI, Ryohei ...
    Article ID: 17.421
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Along with the improved accuracy of MEMS gyroscopes and accelerometers in recent years, JAXA has been studying a navigation-grade Inertial Measurement Unit (IMU) using MEMS gyroscopes and accelerometers for launch vehicles. One issue regarding application of the MEMS IMU for launch vehicles is how to maintain measurement accuracy under high vibration environment during the launch phase. We thus developed a trial model of high accuracy MEMS IMU and evaluated its measurement accuracy under a high vibration environment by conducting random vibration tests. This paper presents the issues of the MEMS IMU for launch vehicles, trial model of the MEMS IMU, and evaluation results of the MEMS IMU under a high vibration environment.

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  • Koichi HAYASHI, Masahiro NISHIDA, Hirohisa KUROSAKI, Toshifumi YANAGIS ...
    Article ID: 17.427
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    In this study, the momentum of the target when collided with a projectile at hypervelocity was measured. Pendulum targets were used in the experiments. The momentums of the target were calculated based on the maximum swing angle of the pendulum. The target material is comparable to aluminum alloy which was used for the rocket body. It is confirmed that, as the impact velocity increases, the ratio of momentum of the projectile before impact and the momentum of the target after impact changes. Furthermore, as the thickness of the target changes, the ratio of momentum of the projectile before impact and the momentum of the target after impact changes.

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  • Junya FUCHITA, Masahiro NISHIDA, Masumi HIGASHIDE
    Article ID: 17.432
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    We examined the effects of impact angle on the penetration depth and hole size of two kinds of ultra-high molecular weight polyethylene fiber fabrics when spherical projectiles with a diameter of 1mm made of aluminum alloy 2017-T4 obliquely struck the fiber fabrics. Impact velocities were 2km/s and 5km/s. In the case of fiber fabrics with high fabric density, the absorbed energy per penetration depth at the impact angle of 45 deg. was greater than that at the impact angle of 0 deg. On the other hand, the absorbed energy per penetration depth of fiber fabrics with low fabric density at the impact angles of 30 deg. and 45 deg. was smaller than that at the impact angle of 0 deg. The impact angle clearly affected the hole size of projectile penetration and its tendency. The penetration mechanism was also discussed.

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  • Ayano INATOMI, Keiichi KITAMURA, Satoshi NONAKA
    Article ID: 17.439
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    It is known that aerodynamic characteristics of a slender body vary substantially at high angles-of-attack (AoAs), and then, will have strong impacts on its flight. For, example, the yaw force makes flight unstable. In this study, we investigated the relation between the yaw force and the configuration, and details of flowfield around the slender-bodied-vehicle numerically. The configuration consisting of “nose cone” and “square aftbody” parts was employed as the baseline, and then, compared with other three configurations having different fineness ratios. According to our computed results, in the case of 50 degrees of AoA, the longer the model became, the more asymmetry appeared: yaw force and asymmetry were found to be attributed not only to the length of the body, but also to the nose bluntness. On the contrary, in the case of 140 degrees, the shorter the model became, the more asymmetry appeared. Furthermore, the large nose bluntness increased CY. Interestingly, this trend is totally opposite to that observed at 50 degrees. It had been considered that the large nose bluntness and the small fineness ratio can reduce asymmetry and CY, however, this study showed that it is not true in the case over 90 degrees, due to complex wake flow structure discovered in the present numerical simulations.

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  • Jongbum KIM, Hyochoong BANG
    Article ID: 17.447
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper proposes static attitude and rate feedback controllers with an observer-based disturbance estimation technique for the attitude control of spacecraft inertial pointing, using only magnetic torquers. Disturbances widely exist in real-world control systems and bring adverse effects to the performance of control systems. Since the disturbances cannot be measured directly, a modified nonlinear disturbance observer was applied to estimate the system uncertainty including unknown moments of inertia and external disturbances, and then to introduce feedforward compensation to cancel it. The numerical simulation results demonstrate that the proposed new control approach allows faster convergence of the closed-loop system to the desired equilibrium and better control efficiency under the lumped uncertainty.

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  • Akihito TOBA, Ikkoh FUNAKI, Yoshiki YAMAGIWA
    Article ID: 17.455
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper discusses a transfer system between the Earth and Mars orbit using electric propulsion under the assumption of launching the H-IIA launch vehicle on a one-way trip. The spacecraft was assumed to be launched into the geocentric orbit, then transferred to the Earth’s heliocentric orbit using electric propulsion or a kick motor, and further transferred to Mars revolving orbit using electric propulsion. The dependency of the payload mass on the specific impulse of the propulsion and launch system were investigated by performing orbit optimization based on the direct collocation method. As a result, the most suitable transfer method to Mars orbit was the combination of a kick motor from the geostationary transfer orbit to the Earth’s heliocentric orbit, and subsequently the use of electric propulsion to transverse to Mars orbit with C3 = 9 km2/s2. The maximum payload mass was 1,500 kg for a specific impulse of 3,000s.

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  • Sumio KATO, Shoichi MATSUDA, Naoyuki SHIMADA, Shunsuke SAKAI, Keiichi ...
    Article ID: 17.461
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The coking phenomenon within a lightweight carbon-phenolic ablator exposed to the heating environment of air is investigated. The existing one-dimensional charring ablation analysis code is modified so that the coking behavior of the ablator can be calculated as well as the thermal response behavior within a lightweight carbon-phenolic ablator. The mass conservation equations for a pyrolysis gas and carbon in the gas are given. The energy equation including the coking process is also presented. The measured density distributions of some arc-heated CFRP ablator samples are compared with those calculated by the ablation analysis code, from which good agreement is obtained. The density profiles with and without coking are compared. The effect of temperature dependency of carbon mass fraction in a pyrolysis gas in the coking equation upon the density profile is examined. The effect of heating rate upon the density distribution in an ablator is also examined. The effect of coking upon the surface recession is studied analytically and experimentally.

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  • Masayuki IKEUCHI
    Article ID: 17.471
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    The objective of this paper is to study the effect of observation by Angle Only Navigation to plan non-cooperative Active Debris Removal approach for debris mitigation, and to have a concept of criteria for safe operation and mission assurance.

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  • Jun MATSUSHIMA, Hironori SAHARA, Shogo ASANO, Masahiro KAKU, Toshihiro ...
    Article ID: 17.477
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    We have been developing a microsatellite based on our concept of a satellite to meet the potential needs of challenging space-science missions that only a microsatellite can accomplish. A binary black hole (BBH) is a state in which two black holes at the center of their respective galaxies are closing the orbital distance around each other. Observations using conventional large satellites have obtained insufficient results for BBH exploration because the satellites cannot be engaged in the long-term and concentrated observation of astral body such as BBH which is not established the existence. Microsatellites have two advantages; namely, they can be occupied with long-term observation, and they have a low-cost and short-term development compared with large satellites. Thus, we can possibly program a challenging mission for a microsatellite, even with a certain risk. We implemented two key technologies on our microsatellite named ORbiting Binary black-hole Investigation Satellite (ORBIS), namely, a Distributed Architecture with a Common Signboard System and mission-equipment space for astronomical observation equipment. The specifications and progress of each subsystem are reported in this paper, along with an outline and the current status of the ORBIS development.

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  • Hiroki NAKANISHI, Ryuhei TAKAGI, Mitsushige ODA
    Article ID: 17.483
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper proposes a novel passive sun-oriented control using the solar radiation pressure torque. Satellites that solar array panels are allocated as an umbrella is assumed. The top of the umbrella is oriented to the sun direction by the sun pressure and its weathercock stability. In order to dump the oscillation, a reflectance control device is attached on the solar array panels. The method realizes the sun-oriented without any other attitude control devises in the satellite. The availability of the method is evaluated in case of a solar-sail type spacecraft, a 50cm-class LEO satellite, and a 1U CubeSat by numerical simulations. Furthermore, a combination of the proposed control and the other passive attitude control is discussed.

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  • Hirohisa ASANO, Hironori SAHARA
    Article ID: 17.491
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    We propose a method that enables a satellite to decide its operation mode by using a distributed architecture with a common signboard subsystem, where each subsystem is regarded as an independent player in a game; we then simulate the operation mode and its transition in the satellite, based on game theory. The status of the satellite is expressed with the remaining-battery ratio and data-accumulation ratio on two axes, and we define two thresholds for each axis. By adopting a dynamic cooperative game model, in which the thresholds are determined dynamically, the mode transition was adjusted depending on the satellite status, and the time efficiency of the mission mode was improved.

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  • Yusuke OZAWA, Shota TAKAHASHI, Javier HERNANDO-AYUSO, Stefano CAMPAGNO ...
    Article ID: 17.496
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    OMOTENASHI is a 6U CubeSat that will be launched in 2019 by the Space Launch System (SLS) with the objective of landing on the Moon. The CubeSat is planned to perform two deterministic maneuvers. The first maneuver (DV1) by gas jet propulsion system transfers the probe from the nominal SLS trajectory to a lunar targeted trajectory. The second maneuver (DV2) is applied by the solid rocket motor before landing to counteract the vertical component of the S/C velocity. The high approach speed at the Moon, combined with large errors induced by the solid motor, requires the probe to approach the Moon with a shallow Flight Path Angle (FPA). If the angle is too steep, expected errors in the DV2 may cause the probe to crash. However, a shallow FPA increases the probability of a Moon-flyby or collision with the local topography. In this paper, we present a design method for Earth-Moon transfer trajectory robust to orbit determination (OD) and DV1 execution errors. First step consists of a grid search to determine the nominal DV1 vector with four candidates obtained. Subsequent error analysis suggests the need for a Trajectory Correction Maneuver (TCM). For the two scenarios of OD error provided by the navigation team, an error analysis was conducted including the TCM. Two realistic OD error scenarios were considered: 30 min or 3 hours of two-way Doppler and range measurement. Error analysis conducted considering TCM shows the need for 3 hours of OD to achieve nearly 100% of transfer success rate.

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  • Keiko MIYATA
    Article ID: 17.506
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    JAXA offers a program called “Aerospace School” to high school students as a form of informal education. Participants are divided into teams and work together to come up with a theme for their mission at various JAXA facilities. They also allocate roles and responsibilities among themselves. The goal is not only to provide Science, Technology, Engineering and Mathematics (STEM) knowledge, but also to build their confidence. We hope this experience will help young adults think about their future career paths, and we strive to actively help them realize their potential. This paper presents the methods, specific examples of, and changes to the Aerospace School program that occurred between 2014 and 2017.

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  • Koji FUJITA, Hiroshi TOKUTAKE, Hiroki NAGAI, Akira OYAMA
    Article ID: 17.512
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Airplanes are paid attention as a new platform for Mars exploration. A high-altitude flight test using balloon was conducted in June 2016 by Japanese working group for Mars exploration aircraft. This paper reports a method of control gain tuning for the flight test using evolutionary computation approach. This method can find optimal robust control gains efficiently and automatically. The combination of the control gains are evaluated by the simulations of a finite number of the dispersion conditions defined by the sensitivity analysis. A summary of a flight test, a control law, an optimization method, a flight simulation method, an evaluation function setting, and an optimization result are described.

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  • Viscor TOR, Harunori NAGATA
    Article ID: 17.519
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    This paper describes the error and uncertainty analysis of the CAMUI hybrid rocket regression simulator. Simulation errors compared to test firings are described and followed by an analysis of the potential uncertainties causing this error. For each uncertainty identified, a sensitivity analysis is then performed with the help of a custom-built simulator to evaluate its impact on the simulator accuracy. It was found that uncertainties in LOX travel time, Reynolds number grouping and model assumptions for the first upstream burning surface have the largest impact on the simulator accuracy and are identified as the main focus points for further research.

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  • Masayuki TAKAHASHI, Naofumi OHNISHI
    Article ID: 17.525
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    To analyze the effects of a magnetic-field distribution and an ambient pressure on the axial, lateral, and angular impulses of a microwave rocket sustained by an external magnetic field, a shock wave propagation was numerically reproduced by solving a compressible fluid dynamics equation. This equation involved an energy source evaluated based on a fully kinetic simulation coupled with an electromagnetic wave propagation. The external magnetic field having a lateral offset against the vehicle axis was applied to the microwave-rocket nozzle to induce the asymmetric shock wave for obtaining the postural control force. Negative impulses in the lateral and angular directions were obtained when the magnetic field with a lateral offset of 3.0 cm was applied to the discharge region at ambient pressures of 0.003 atm. However, the directions of the lateral and angular impulses reversed when the ambient pressure was changed from 0.003 atm to 0.006 atm, despite maintaining the lateral offset of the magnetic field at 3.0 cm because the decay timing of the shock wave inside the rocket nozzle was changed. It is necessary to increase the vehicle radius or decrease the energy absorbed by the plasma to obtain the same direction impulse, regardless of the ambient pressure, because postural control is difficult when the impulse direction depends on the ambient pressure.

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  • Masayuki TAKAHASHI, Naofumi OHNISHI
    Article ID: 17.531
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    Thrust-generation processes were numerically reproduced using a computational fluid dynamics code in a microwave-rocket system. The nozzle-shape dependence of the thrust performance was evaluated when an external magnetic field satisfying electron cyclotron resonance heating condition was applied to the rocket nozzle to enhance shock waves induced by the microwave irradiation. A larger-radius nozzle could not cancel out a negative thrust after a positive thrust because compression waves reflected from an open end of the rocket nozzle became weaker. Utilizing the smaller-radius nozzle is better to achieve the higher thrust performance because the faster and stronger pressure restoration is obtained from the open end of the rocket nozzle.

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  • Yosuke KAWABATA, Takanao SAIKI, Yasuhiro KAWAKATSU
    Article ID: 17.538
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    On-board orbit determination (OD) using directions of celestial bodies, planets and asteroids, in the Solar System for the Autonomous Navigation (AutoNav) is introduced in this paper. For deep space missions, OD has been performed by Range and Range Rate (RARR), which is a traditional ground tracking approach by radio waves. RARR enables the higher accuracy of OD than other methods. However, such radio navigation has the inevitable problems, such as strength reduction of radio waves and the transmitter limitation. Furthermore, people must stay and operate the spacecraft on the ground station, which makes the operating cost and burden considerable. Therefore, there has been a growing interest in the autonomy of the spacecraft in recent years to avoid the above-mentioned problems. This paper considers on-board OD using directions of celestial bodies from spacecraft. In particular, the selection of target bodies to observe is focused on because it's important that the selection of such target bodies leads to the satisfaction of mission requirements or increment of scientific observation. Then, this paper presents the method for the target selection, which is computationally cheap and makes the target selection easy.

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  • Landon KAMPS, Harunori NAGATA
    Article ID: 17.544
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    A new performance parameter titled “tubular equivalent regression rate” is introduced to evaluate burning rates in hybrid rockets with geometrically complex solid propellant grains. Tubular equivalent regression rates are calculated for eight previously reported CAMUI-type hybrid rocket firing tests and compared with extrapolations of previously reported empirical correlations for classic, swirl and vortex hybrid rockets. A non-dimensional number titled “CAMUI Number” is introduced to evaluate how CAMUI-like a solid propellant grain is. The CAMUI Number ranges from 0-1: 0 means no CAMUI-type blocks are used, 1 means only CAMUI-type blocks are used. The results show that the tubular equivalent regression rate increases logarithmically with CAMUI Number, and approaches a value of around 3 [mm/s] for a CAMUI Number of 1. This increase in tubular equivalent regression rate is shown to correspond to an increase in performance range from a classic (tubular) hybrid rocket at low CAMUI Numbers (0.1) to surpassing a vortex hybrid rocket for high CAMUI Numbers (>0.7). Furthermore, through the block-by-block analysis of tubular equivalent regression rate in a fuel grain with a CAMUI Number of 0.71, it is shown that maximum burning rates were achieved in blocks under slightly oxidizer rich conditions.

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  • Kenichi TABATA, Madoka NAKAJIMA, Naohiko KOHTAKE
    Article ID: 17.552
    Published: 2019
    [Advance publication] Released: January 31, 2019
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    To realize indoor location based services, indoor positioning function is the main function. However, available solutions such as Google Maps are not provided yet. In most cases, it is necessary for the service provider to develop the positioning environment themselves. We consider that this point is one of the reasons why indoor positioning technology has not spread significantly. In this study, we defined “the simplification of developing indoor positioning environment” as “to realize the development of an indoor positioning environment by a user,” and proposed a method for process optimization to solve the indoor positioning environment issue using a design structure matrix. Moreover, we verified the effectiveness of the proposed method by applying it to an existing use case of developing an indoor positioning environment and validated that the proposed method can create an optimized process.

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