AOCS DESIGN FOR SCIENTIFIC MISSIONS ROSETTA/MARS EXPRESS

摘要

In the frame of the ESA scientific missions ROSETTA and MARS EXPRESS, MATRA MARCONI SPACE is developing AOCS solutions to cope with specific mission needs. The purpose of the present paper is to put forward the constraints that have driven the AOCS design and to describe some of the concepts which have been chosen for both missions. Among the design drivers are worth noting: 1. autonomy level : tightly adapted to the different mission needs and on-board resources, 2. AOCS flexibility: the AOCS modes which are being developed have to face extremely different environment conditions which depend on mission phases (variable sun distance, variable perturbation levels, ...) and to provide numerous pointing facilities, 3. specific AOCS equipment: autonomous star tracker, navigation camera, accelerometers for orbit correction, 4. dynamic constraints: lander ejection, sloshing disturbances, large flexible appendages, articulated antenna. 5. performance achievement: orbit correction accuracy, pointing and stability requirements during operational phases, In addition to the general mission requirements the AOCS design and development has taken into account the stringent budget and planning constraints. This paper also shows how these latter constraints have led to the optimisation of the commonality between both satellites and of the development strategy.