Advanced Microsatellite Mission—deep space applications and constraints

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 nondeployable equipment (tanks, star sensor baffles, etc.) becomes 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 ΔVΔV. There has historically been a quest for ever higher values of IspIsp for SEP thrusters, but it is shown that a full mission-level trade-off taking into account the restricted power availability on this class of spacecraft often leads to a lower value of IspIsp 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.