Validation of the in-flight calibration procedures for the MICROSCOPE space mission

TL;DR

This paper validates in-flight calibration procedures for the MICROSCOPE space mission, which tests the Equivalence Principle with high precision, by analyzing calibration methods and using a simulator to ensure measurement accuracy.

Contribution

It introduces and evaluates calibration procedures and a simulator for the MICROSCOPE mission, enhancing measurement accuracy for space-based gravity tests.

Findings

Calibration procedures are effective for in-flight correction.

Simulator validates the analytical calibration performance.

In-flight calibration is essential for similar drag-free space missions.

Abstract

The MICROSCOPE space mission aims to test the Equivalence Principle with an accuracy of $10^{-15}$. The drag-free micro-satellite will orbit around the Earth and embark a differential electrostatic accelerometer including two cylindrical test masses submitted to the same gravitational field and made of different materials. The experience consists in testing the equality of the electrostatic acceleration applied to the masses to maintain them relatively motionless. The accuracy of the measurements exploited for the test of the Equivalence Principle is limited by our a priori knowledge of several physical parameters of the instrument. These parameters are partially estimated on-ground, but with an insufficient accuracy, and an in-orbit calibration is therefore required to correct the measurements. The calibration procedures have been defined and their analytical performances have been evaluated. In addition, a simulator software including the dynamics model of the instrument, the satellite drag-free system and the perturbing environment has been developed to numerically validate the analytical results. After an overall presentation of the MICROSCOPE mission, this paper will describe the calibration procedures and focus on the simulator. Such an in-flight calibration is mandatory for similar space missions taking advantage of a drag-free system.