The satellite is roughly one meter-cube featuring two deployable solar panels on one side. The star tracker and mechanical and thermal interface of the payload are fixed on the opposite side. The two lateral sides carry four pods of three electrical thrusters used for the satellite attitude and orbit control.
The MICROSCOPE satellite includes a fine original drag-free control system which enables compensation of the applied surface forces, like solar pressure and residual atmosphere drag which deviate the orbit from a pure gravitational one. The actuation of the thrusters is performed with respect to the measurements delivered by the payload accelerometers and the star tracker. Both attitude and linear satellite motions are finely controlled to reduce the acceleration applied on the instrument, and thus enhance its resolution. The attitude and drag-free control should present motion reduction noises as low as 10-12m.s-2/Hz1/2.
