Determination of on-board accelerometer's characteristics for METRIC mission

METRIC is a proposed mission that aims to improve the knowledge of atmospheric density, general relativity and geodesy. The mission foresees a small spherical satellite placed in a polar eccentric orbit, with the apogee at 1200 km of altitude and perigee at 450 km. The spacecraft will be tracked from ground and space and have an on-board accelerometer. The last one will measure non-gravitational accelerations (namely due to drag and solar radiation pressure). A dynamical simulator has been implemented with known models (e.g. gravitational model, NRLMSISE-00), so that, through some simulations, it’s possible to estimate the non-gravitational accelerations acting on the satellite. These are then analyzed in order to extract their principal characteristics: intensity and frequency spectrum. In this way accelerometer’s features - dynamic range, required accuracy and frequency bandwidth- can be determined in order to have useful measurements. The data collected by the accelerometer will be used, also with POD data that comes from tracking, to improve the models of atmospheric density and general relativity.