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In future lunar exploration, mobile robots (i.e., rovers) are required to travel long distances; thus, these rovers will experience severe power limitations. In such exploration missions, the power limitation on the Moon, i.e., the balance between consumed power and that generated by the rover, should be taken into account for motion/path planning. Power generated by solar panels is a possible resource, which is determined depending on the condition of shadows. From this possibility, this study evaluates the influence of these shadows on path planning for lunar rovers by using a proposed path planning method, in which the power limitation is introduced as a new evaluation index. For this evaluation, we developed a path-planning simulator based on a method using digital elevation models (DEMs) derived from Kaguya data. In the simulation, the terrain inclination and shadow on the Moon are estimated by using the DEMs. Using this simulation, path planning is conducted under various insolation (i.e., shadow) conditions corresponding to latitude, longitude, and time for a given terrain. The simulation results show that the power level can be increased in a planned path by considering the influence of the shadow. The effectiveness of the proposed path-planning method is quantitatively confirmed, particularly for an exploration mission conducted in the morning and evening at middle/high latitudes., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730001000, レポート番号: JAXA-RM-17-001E

月面模擬環境において、モータの特性評価を行う試験装置を開発した。この装置は真空チャンバの外部から内部のモータの回転速度や負荷を制御するとともに、モータの回転速度や出力トルクを計測することが可能である。さらに、この装置を用いて、(1)温度試験および(2)熱サイクル試験を実施した。(1)の試験では、異なる温度におけるモータの挙動、(2)の試験では、「低温で保存し、その後加熱する」というサイクルを繰り返した場合のモータの挙動について、それぞれ検証を行った。これら試験より、月面の温度環境において、試験に使用したモータがほぼ同一性能で保存・動作可能であることを確認した。この研究の成果は、月面探査の信頼性向上に寄与するものである。, On the surface of the Moon, mobile robots (i.e., rovers) are required to travel in vacuum and experience extreme low and high temperatures. Thus, for developing lunar rovers, the survivability and performance of the rovers' components should be evaluated in an environment simulated the above target situation. To this end, this paper investigates a characteristics of a motor in a simulated lunar thermal vacuum condition. For this investigation, a thermal vacuum test system was first developed. In this system, a motor located inside a vacuum chamber is controlled from outside the chamber, and motor's speed, current, and torque are measured in various load conditions. Subsequently, two kinds of motor tests were proposed and conducted using this system. In a test, a motor was tested in different operation temperatures. In the other test, the motor was tested in thermal cycles, in which the motor was first stored in a low temperature and subsequently operated after heated. Here, operation and storage temperatures were determined based on the lunar thermal conditions. The test results suggest that the motor can be stored and have almost constant speed, torque, and thermal performances under the simulated lunar environment. This study confirms the thermal characteristics of an indispensable component for lunar exploration and enhanced its reliability., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730002000, レポート番号: JAXA-RM-17-002

第17回宇宙科学シンポジウム (2017年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 17th Space Science Symposium (January 5-6, 2017. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 著者人数: 11名, 資料番号: SA6000060041, レポート番号: S5-026

第16回宇宙科学シンポジウム (2016年1月6日-7日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 16th Space Science Symposium (January 6-7, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 著者人数: 11名, 資料番号: SA6000046252, レポート番号: S5-004