川口 淳一郎

In this article, preliminary feasibility assessment of aeroassist systems for JAXA's future Mars Exploration has been conducted. The aerobraking technology is found to bring about an increase in the payload ratio by considerable reduction of the propellant mass required for orbital descent after propulsive orbital insertion. The aerocapture technology, if accuracy in both the interplanetary orbit determination and guidance is improved, is shown to achieve a remarkable increase of the payload mass using the state-of-the-art technologies. Discussions are made on the guided entry systems which are expected to realize better landing mark precision than obtained by the ballistic flight.

As many varieties of microsatellite missions have been purposed, microsatellite's performances are becoming higher level. It is important to develop higher level 3-axis attitude control mechanics. We purpose an innovative 3-axis attitude control for microsatellite by using Reflectivity Control Device, RCD which is capable of changing its reflectance by imposed voltage. This paper shows one example of 3-axis attitude control using RCD, and advantages of this method by being compared to non RCD methods which used only reaction wheel.

火星複合探査WGは数多くの議論を通じて,MELOS計画の根幹である科学目標とそれに答えるための科学要求をまとめてきた.火星はなぜ赤いのか?この単純でしかし奥深い問題に答えるには,大気圏・表層・固体圏を一つの惑星システムとして捉える複合探査が必要である.MELOSは,まさにそれを目指そうとしている.

This paper describes the attitude dynamics of spacecraft with large flexible structure, such as huge antenna or membrane of solar sail. The coupled motion of the rigid spacecrafts with the flexible structure is complicated, and it is important to predict the motion for the design of configuration or operation planning. It requires a lot of time to calculate the motion of the flexible structure by numerical simulation, and the analysis using simple model is important for exhaustive validation. In this study, a simplified model of the attitude dynamics considering the first vibration mode of flexible structure is introduced. Using this model, the vibration mode of the attitude motion of spacecraft is analyzed. The result of the analysis is confirmed with numerical simulation and compared with the result obtained by use of proven model.