Status of Development of the Future Accelerometers for Next Generation Gravity Missions

Abstract

The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory) and GFZ (GeoForschungsZentrum), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth’s gravity field variation providing global climatic data during 5 years at least. Europe and US propose new gravity missions beyond GRACE-FO, with improved performance thanks to laser interferometry and better accelerometers. ONERA has procured the accelerometers for the previous geodetic mission (CHAMP, GRACE, GOCE and now GRACE-FO) and continues to improve the instruments to answer to the challenge of the future missions according to two main domains: Firstly, a new design of electrostatic accelerometer is proposed, based on MicroSTAR configuration, a 3-axes ultra-sensitive accelerometer, with a cubic proof-mass. Secondly, ONERA studies the hybridization of such electrostatic accelerometer with cold atom interferometer technology in order to take advantage of each instrument (high sensitivity for electrostatic accelerometer in short term, and absolute measurement for atom interferometer). A first result of the hybrid instrument, obtained on ground, is presented.