Riyo Yamanaka
Japan Aerospace Exploration Agency
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Featured researches published by Riyo Yamanaka.
PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT: Proceedings of the#N#9th International Conference: Protection of Materials and Structures From Space#N#Environment | 2009
Yugo Kimoto; Shoichi Ichikawa; Eiji Miyazaki; Koji Matsumoto; Junichiro Ishizawa; Hiroyuki Shimamura; Riyo Yamanaka; Mineo Suzuki
A space materials exposure experiment was condcuted on the exterior of the Russian Service Module (SM) of the International Space Station (ISS) using the Micro‐Particles Capturer and Space Environment Exposure Device (MPAC&SEED) of the Japan Aerospace Exploration Agency (JAXA). Results reveal artificial environment effects such as sample contamination, attitude change effects on AO fluence, and shading effects of UV on ISS. The sample contamination was coming from ISS components. The particles attributed to micrometeoroids and/or debris captured by MPAC might originate from the ISS solar array. Another MPAC&SEED will be aboard the Exposure Facility of the Japanese Experiment Module, KIBO Exposure Facility (EF) on ISS. The JEM/MPAC&SEED is attached to the Space Environment Data Acquisition Equipment‐Attached Payload (SEDA‐AP) and is exposed to space. Actually, SEDA‐AP is a payload on EF to be launched by Space Shuttle flight 2J/A. In fact, SEDA‐AP has space environment monitors such as a high‐energy partic...
Proceedings of SPIE | 2016
Eiji Miyazaki; Kazunori Shimazaki; Osamu Numata; Miyuki Waki; Riyo Yamanaka; Yugo Kimoto
Outgassing rate measurement, or dynamic outgassing test, is used to obtain outgassing properties of materials, i.e., Total Mass Loss, “TML,” and Collected Volatile Condensed Mass, “CVCM.” The properties are used as input parameters for executing contamination analysis, e.g., calculating a prediction of deposition mass on a surface in a spacecraft caused by outgassed substances from contaminant sources onboard. It is likely that results obtained by such calculations are affected by the input parameters. Thus, it is important to get a sufficient experimental data set of outgassing rate measurements for extract good outgassing parameters of materials for calculation. As specified in the standard, ASTM E 1559, TML is measured by a QCM sensor kept at cryogenic temperature; CVCMs are measured at certain temperatures. In the present work, the authors propose a new experimental procedure to obtain more precise VCMs from one run of the current test time with the present equipment. That is, two of four CQCMs in the equipment control the temperature to cool step-by-step during the test run. It is expected that the deposition rate, that is sticking coefficient, with respect to temperature could be discovered. As a result, the sticking coefficient can be obtained directly between -50 and 50 degrees C with 5 degrees C step. It looks like the method could be used as an improved procedure for outgassing rate measurement. The present experiment also specified some issues of the new procedure. It will be considered in future work.
Proceedings of SPIE | 2014
Eiji Miyazaki; Yuka Miura; Osamu Numata; Riyo Yamanaka; Susumu Baba; Junichiro Ishizawa; Yugo Kimoto; Takashi Tamura
Outgassing rate measurements are basically performed for fresh materials, e.g. just cured adhesives, paints, etc. and reveal a lot about how the material can behave as a contamination source. It is also important to determine the bakeout process sufficiently. In the present study, a typical silicone adhesive for use in space, RTV S-691, Wacker Chemie, was selected for the measurement. Two cured specimens, 40 × 40 mm in size, were applied for several isothermal tests under identical conditions: a specimen at 125 degrees C for 144 hours with CQCM at -193 degrees C to measure TML. Consequently, it was determined that the TML and TML rate could be reduced by bakeout as expected. It also emerged that a longer bakeout, i.e. a longer cumulative bakeout time, for the material would reduce the TML and TML rate more effectively. The results suggest that bakeout mainly affects the behavior in the “low-rate” phase, whereby the TML rate curve can be divided into two phases. The elapsed time for a specimen can also be considered the cumulative test time. Based on the cumulative elapsed time, the TML rate curve is replotted and a correlation emerges between the cumulative bakeout time and TML rate. The first measurement data of TML and the TML rate could be affected by the stored time from cure, which might result from the change in unreacted substances declining as the stored time elapsed.
Proceedings of SPIE | 2014
Yuka Miura; Susumu Baba; Riyo Yamanaka; Osamu Numata; Eiji Miyazaki; Junichiro Ishizawa; Yugo Kimoto; Takashi Tamura
Molecular contamination by outgassing can degrade the performance of optical components. In orbit, spacecraft are exposed to various environments. UV is one of the most critical. It may also have the potential to cut the chains of organic molecules in contaminants due to its high energy, degrading optical properties and even re-emission behavior. In the present study, using two kinds of UV sources with different wavelength ranges, we compare the effect of UV lights irradiated on an optical surface with silicone contaminants. The irradiated samples were evaluated in terms of their optical properties and re-emission behavior, i.e. transmittance, and thermal desorption.
Proceedings of SPIE | 2014
Susumu Baba; Eiji Miyazaki; Yuka Miura; Riyo Yamanaka; Osamu Numata; Junichiro Ishizawa; Yugo Kimoto; Takashi Tamura
JAXA is developing a contamination analysis tool “J-SPICE” (Japanese Spacecraft Induced Contamination analysis software). Generally speaking, contamination analysis tools predict based on various input data and mathematical models of contaminant behavior, which means prediction accuracy depends on the validity of mathematical models as well as of input data. We investigated the validity of a diffuse reflection model applied in J-SPICE by comparing the reflection flux of contaminant molecules measured by the ground experiment and the analytical result of the J-SPICE. The result showed that the diffuse reflection model of J-SPICE reasonably explains molecule distribution reflected by a flat surface.
Earth and Planetary Science Letters | 2011
Takaaki Noguchi; Tomoki Nakamura; Takayuki Ushikubo; Noriko T. Kita; John W. Valley; Riyo Yamanaka; Yugo Kimoto; Yukihito Kitazawa
Journal of The Japan Society for Aeronautical and Space Sciences | 2008
Fumitaka Urayama; Keiichi Yano; Riyo Yamanaka; Eiji Miyazaki; Yugo Kimoto
Journal of Spacecraft and Rockets | 2011
Riyo Yamanaka; Takaaki Noguchi; Yugo Kimoto
Archive | 2009
高明 野口; Takaaki Noguchi; 智樹 中村; Tomoki Nakamura; 幸人 北澤; Yukihito Kitazawa; 理代 山中; Riyo Yamanaka; 雄吾 木本; Yugo Kimoto; 峰男 鈴木; Mineo Suzuki
Archive | 2009
幸人 北澤; Yukihito Kitazawa; 顕 藤原; Akira Fujiwara; 敏彦 門野; Toshihiko Kadono; 高明 野口; Takaaki Noguchi; 理代 山中; Riyo Yamanaka; 雄吾 木本; Yugo Kimoto; 峰男 鈴木; Mineo Suzuki