The objective of this activity is to assess the feasibility of a high-resolution accelerometer in order to increase the station keeping autonomy in relation with the electric engine of the @BUS platform.
The accelerometer would be used to measure the East/West drift of the satellite during the North/South thrusts. It would permit to define in real-time the maximum North/South thrust time in order to obtain an acceptable East/West drift while not requiring control from ground stations.
The key issues of the study are:
The current project will lead to the implementation of a versatile and high-performance accelerometer exhibiting nano-g resolution.
The accelerometer is servo-controlled and electrostatic.
It is based on the electrostatic levitation of a 20g proof-mass inside an electrode cage. Capacitive position sensors detect the displacements of the proof-mass, deliver the information to the servo-control which in turn maintains the proof-mass at the centre of the cage by applying the appropriate potentials on the electrodes.
The mechanical core is mounted on a reference sole plate and enclosed in a hermetic housing. The front-end electronics surrounds the housing: it consists of 6 capacitive sensors and 6 analog correcting networks for controlling the motion of the proof-mass along the 6 degrees of freedom.
The activity focuses on the concept definition and performance model of the accelerometer including:
The first phase of the activity has been successfully completed, showing the feasibility of a new concept using accelerometers for increased on-orbit autonomy. For Alphabus an alternative option has been chosen to achieve on-orbit autonomy, and it has therefore been decided not to pursue the activity.