Spacecraft charging analysis for Chandrayaan-2 mission

The interaction of a spacecraft with its orbital environment is a major consideration which must be addressed during the design of any space system, since a variety of hazards are associated with the operation of spacecraft in the harsh space environment. The Indian lunar mission Chanrayaan-2 spacecraft was expected to experience different plasma environmental conditions during its full mission life. These plasma environments include environment during earth centric phase, transfer to lunar orbit phase, lunar orbit phase & post landing phase. Out of all plasma environment conditions, earth bound phase is much more severe than any GEO mission as spacecraft is expected to cross Van-Allen belt 44 times. Moreover, lander geometry was totally new from previous ISRO missions in terms of spacecraft charging aspects. In this paper, the spacecraft requirements in view of spacecraft charging has been analysed. This paper briefly explains the theoretical analysis which estimates the potential developed due to surface and internal charging. Based on this estimation, changes in spacecraft structure were proposed to implement at the design phase and same had been implemented in spacecraft to achieve a successful mission. The guidelines proposed here are applicable to all future lunar missions which passes through multiple orbital maneuver to achieve earth escape velocity and have same kind of structure.