ADVANCED MICROSATELLITE MISSION - DEEP SPACE APPLICATIONS AND CONSTRAINTS

摘要

One very cost-effective route into orbit is as an Auxiliary Microsatellite on the ASAP-5 structure. All planned flights of the ASAP-5 structure are into GTO. The Advanced Microsatellite Mission study carried out within the ESA General Studies Programme addressed the feasibility of a deep space mission starting from this point. One of the major configuration drivers in the ASAP-5 launch envelope is the available volume. Low density non-deployable equipment (tanks, star sensor baffles etc.) become design drivers. Optimisation for power and volume has led to an Attitude Control System architecture which is gyro-based (using the latest high performance MEMS devices) making use of opportunistic calibration by minimally baffled star sensors. Solar Electric propulsion appears the leading candidate for missions requiring large ΔV. There has historically been a quest for every higher values of I_(sp) for SEP thrusters, but it is shown that a full mission-level tradeoff taking into account the restricted power availability on this class of spacecraft often leads to a lower value of I_(sp) in order to minimise operations costs and improve the timeliness of scientific observations. It is concluded that useful deep space missions can be performed by a spacecraft complying with the ASAP-5 constraints.