On-ground actuator calibration for ISA — BepiColombo

The key role of the Italian Spring Accelerometer (ISA) in the radio science measurements of the ESA BepiColombo mission to Mercury is to remove, a posteriori, the non-gravitational accelerations acting on the Mercury Planetary Orbiter (MPO) due to the very strong radiation environment around Mercury. This paper is devoted to describe the on-ground actuator calibration procedure along with the facility assembled to carry it out. Such a calibration is necessary to guarantee the accelerometer performance and hence to reach the very ambitious objectives of the Radio Science Experiment (RSE) of the ESA mission.