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Noriyuki Namiki Takahiro Iwata Nobuyuki Kawano Fumio Fuke Naoki Tateno Kazuyoshi Asari Hirotomo Noda Yusuke Kono Hideo Hanada Yukihiro Yahagi Zen’ichi Yamamoto Koji Tanaka Mitsuo Yamada Koji Matsumoto Sander Goossens 《Space Science Reviews》2010,154(1-4):103-121
The Japanese lunar mission Selenological and Engineering Explorer (SELENE) was launched in September 2007 and continued its mission until June 2009, when the main orbiter impacted with the surface of the Moon. SELENE consisted of three satellites: Main, Rstar, and Vstar. Rstar’s tasks were to forward up-link signals from the Usuada Deep Space Center (UDSC) to Main, and to down-link returning signals from Main to UDSC. We refer to this tracking sub-system as a four-way Doppler measurement. In contrast, conventional tracking systems between Rstar and UDSC as well as between Main and ground stations are referred to as two-way Doppler and range measurements. Using Main and Rstar, we successfully observed the gravity field over the farside of the Moon. Because four-way Doppler measurements via a relay sub-satellite were a fundamental experiment in space for Japanese space agencies, compatibility of radiometric instruments onboard Main and Rstar to UDSC were carefully examined at the UDSC using components manufactured for flight models. These tests not only proved the feasibility of the four-way Doppler measurements but also provided biases and variations of the four-way Doppler and two-way Doppler and range measurements that were later taken into account during the processing of tracking data and the analysis of the lunar global gravity field. 相似文献
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Kazuyoshi Takahashi 《Space Science Reviews》1989,51(1-2):123-146
A review is presented of solar neutron observation by ground-based neutron monitors (NM), focusing on the five solar neutron events of 1980 June 7, 1980 June 21, 1980 November 6, 1982 November 26, and 1984 April 25 observed by the Tokyo NM. These events are analyzed by comparison with the time profiles of gamma-rays observed by the Gamma-Ray Spectrometer (GRS) on the Solar Maximum Mission (SMM) satellite and with the enhancements of counting rate observed at various NM stations in the solar neutron event of 1982 June 3.The energy range of solar neutrons observed by the NM is estimated in each event, based on some simple assumptions, using the gamma-ray data from the GRS and decay proton data from the ISEE-3 spacecraft. It is shown that these enhancements can be almost completely explained by the continuous emission of solar neutrons for several minutes at the flare. Finally, the effective detection and the newly found possibility to predict, in the short term, the occurrence time of a solar neutron event, and the plans for observation of solar neutrons by the ground-based NM stations are presented. 相似文献
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Kaname Hirayanagi Toyoki Natsuno Tomoki Shiozawa Nobuhisa Yamaguchi Yoriko Watanabe Satomi Suzuki Satoshi Iwase Tadaaki Mano Kazuyoshi Yajima 《Acta Astronautica》2009,64(11-12):1298-1303
The present study examines the prevalence of subjective fatigue in young healthy males during 14 days of 6° head-down bed rest (HDBR) by using a multidimensional questionnaire. Forty-one subjects completed the Subjective Fatigue Scale questionnaire to assess the fatigue-related complaints and symptoms. The questionnaire is composed of three sections, with 10 items each. The sections measured drowsiness and dullness (Section 1), difficulty in concentration (Section 2), and the projection of physical disintegration (Section 3). The subjects answered simple questions between 1400 and 1700 on 6 measurement days before and during the HDBR period. The prevalence rate of low back pain was markedly high (80.5%) on the second day and more than 50% in the first half of the HDBR period, and any complaints related to either a lack of sleep or a deterioration in the quality of sleep continued until the end of the HDBR period. Our findings may be useful in developing preventive strategies against physical and mental fatigue associated with prolonged HDBR, horizontal bed rest, and microgravity environments. 相似文献
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Hideo HANADA Seiitsu TSURUTA Kazuyoshi ASARI Hiroshi ARAKI Hirotomo NODA Shingo KASHIMA Ken-ichi FUNAZAKI Fuyuhiko KIKUCHI Koji MATSUMOTO Yusuke KONO Hiroo KUNIMORI Sho SASAKI 《深空探测学报》2014,1(3):200-204
使用面包板模型和仿真方法,在实验室内研究月球指向就位测量望远镜(ILOM)的基本特征,如望远镜星像中心点位置精度、温度效应、倾斜以及地面震动的影响。使用这个技术预期在月球表面观测月球自转时可以达到1ms的精度。将在地面上开展测试验证观测以全面评价达到优于0.1″观测精度目标所需条件和特征。 相似文献
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Akihiro Doi Yusuke Kono Kimihiro Kimura Satomi Nakahara Tomoaki Oyama Nozomi Okada Yasutaka Satou Kazuyoshi Yamashita Naoko Matsumoto Mitsuhisa Baba Daisuke Yasuda Shunsaku Suzuki Yutaka Hasegawa Mareki Honma Hiroaki Tanaka Kosei Ishimura Yasuhiro Murata Reiho Shimomukai Shoko Koyama 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(1):779-793
The balloon-borne very long baseline interferometry (VLBI) experiment is a technical feasibility study for performing radio interferometry in the stratosphere. The flight model has been developed. A balloon-borne VLBI station will be launched to establish interferometric fringes with ground-based VLBI stations distributed over the Japanese islands at an observing frequency of approximately 20?GHz as the first step. This paper describes the system design and development of a series of observing instruments and bus systems. In addition to the advantages of avoiding the atmospheric effects of absorption and fluctuation in high frequency radio observation, the mobility of a station can improve the sampling coverage (“uv-coverage”) by increasing the number of baselines by the number of ground-based counterparts for each observation day. This benefit cannot be obtained with conventional arrays that solely comprise ground-based stations. The balloon-borne VLBI can contribute to a future progress of research fields such as black holes by direct imaging. 相似文献
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Hideo Hanada Takahiro Iwata Qinghui Liu Fuyuhiko Kikuchi Koji Matsumoto Sander Goossens Yuji Harada Kazuyoshi Asari Toshiaki Ishikawa Yoshiaki Ishihara Hirotomo Noda Seiitsu Tsuruta Natalia Petrova Nobuyuki Kawano Sho Sasaki Kaori Sato Noriyuki Namiki Yusuke Kono Kenzaburo Iwadate Osamu Kameya Katsunori M. Shibata Yoshiaki Tamura Shunichi Kamata Yukihiro Yahagi Wataru Masui Koji Tanaka Hironori Maejima Xiaoyu Hong Jinsong Ping Xian Shi Qian Huang Yusufu Aili Simon Ellingsen Wolfgang Schlüter 《Space Science Reviews》2010,154(1-4):123-144
The Japanese lunar explorer SELENE (Kaguya), which was launched on September 14th, 2007, was the target of VLBI observations over the period November 2007 to June 2009. These observations were made in order to improve the lunar gravity field model, in particular the lower degree coefficients and the model near the limb. Differential VLBI Radio sources, called VRAD instruments, were on-board the subsatellites, Rstar (Okina) and Vstar (Ouna), and the radio signals were observed by the Japanese VERA (VLBI Exploration of Radio Astrometry) network, and an international VLBI network. Multi-frequency and same-beam VLBI techniques were utilized and were essential aspects of the successful observing program. Multi-frequency VLBI was employed in order to improve the accuracy of the orbit determination obtained from the phase delay from the narrow-band satellite signals, while the same-beam VLBI method was used to resolve the cycle ambiguity which is inherent in the multi-frequency VLBI method. The observations were made at three S-band frequencies (2212, 2218 and 2287 MHz), and one X-band frequency (8456 MHz). We have succeeded in correlating the recorded signals from Okina/Ouna, and we obtained phase delays with an accuracy of several pico-seconds at S-band. 相似文献
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H. Hanada T. Iwata N. Namiki N. Kawano K. Asari T. Ishikawa F. Kikuchi Q. Liu K. Matsumoto H. Noda S. Tsuruta S. Goossens K. Iwadate O. Kameya Y. Tamura X. Hong J. Ping Y. Aili S. Ellingsen W. Schlüter 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
The Japanese lunar explorer SELENE (SElenological and Engineering Explorer), to be launched in 2007, will for the first time utilize VLBI observations in lunar gravimetry investigations. This will particularly improve the accuracy to which the low degree gravitational harmonics and the gravity field near the limb can be measured, and when combined with Doppler measurements will enable three-dimensional information to be extracted. Differential VLBI Radio sources called VRAD experiment involves two on-board sub-satellites, Rstar and Vstar. These will be observed using differential VLBI to measure the trajectories of the satellites with the Japanese network named VERA (VLBI Exploration of Radio Astrometry) and an international VLBI network. 相似文献
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