Yasuhiro KAWAKATSU

<p>A Fault Detection, Isolation, and Recovery (FDIR) algorithm for attitude control systems is a key technology to increasing the reliability and survivability of spacecraft. Micro/nano interplanetary spacecraft, which are rapidly evolving in recent years, also require robust FDIR algorithms. However, the implementation of FDIR algorithms to these micro/nano spacecraft is difficult because of the limitations of their resources (power, mass, cost, and so on). This paper shows a strategy of how to construct a FDIR algorithm in the limited resources, taking examples from micro deep space probe PROCYON. The strategy focuses on function redundancies and multi-layer FDIR. These ideas are integrated to suit the situation of micro/nano interplanetary spacecraft and demonstrated in orbit by the PROCYON mission. The in-orbit results are discussed in detail to emphasize the effectiveness of the FDIR algorithm. </p>

平成30年度宇宙輸送シンポジウム（2019年1月17日-18日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000136091レポート番号: STEP-2018-036

<p>JAXA has a plan to send a spacecraft to the Martian moons in the 2020s. The spacecraft needs to transfer to the orbit of one of the Martian moons. In this study, we investigate the maneuver design method and the characteristics of orbit injection that minimizes the velocity increment Δv for the JAXA's Martian exploration mission. In the previous study, a transfer trajectory with three impulsive maneuvers has been demonstrated and it has been shown that setting the initial argument of periapsis to be zero is effective to reduce the Δv for the transfer. In this paper, we proposed the optimal transfer trajectory with four impulsive maneuvers based on the grid searching of maneuver position. First, it is shown that when the declination of v-infinity vector is large relative to the Mars equatorial plane, there exists a region where adopting four impulsive maneuvers reduces the total Δv compared to the three impulsive maneuver transfer. Also, we show that optimal value of the initial argument of periapsis slightly deviates from zero when the declination is large. Finally, we investigate which transfer type has the smaller Δv for each of the possible launch windows of JAXA's Martian exploration mission.</p>