Hybridized Atom / Electrostatic Accelerometer for Space Geodesy

The launch of satellite gravity missions (CHAMP, GRACE, GOCE, GRACE FO), is revolutionizing our knowledge of the global Earth's gravity field and its temporal changes, by the use of ultra-precise space accelerometers. Until now, these accelerometers are based on electrostatic technology which offers a high level of performance and a high degree of maturity. On the other hand, a new generation of sensors based on cold atom interferometry is emerging and seems very promising. These atomic instruments have already demonstrated on ground impressive results, especially with the development of state-of-the-art gravimeters, and should reach their full potential only in space, where the microgravity environment allows very long interaction times. Each of these two types of technology has its own assets which are, for electrostatic, their demonstrated short term sensitivity and their high TRL, and for atom interferometry, amongst others, the absolute nature of the measurement and therefore no need for calibration processes. These two technologies seem in some aspects very complementary and a hybrid sensor bringing together all their assets could be the opportunity to take a big step in this context of gravity space missions.

Here, we present theoretical and experimental developments concerning hybrid atom-electrostatic accelerometer for space application. Particularly, we will present an experimental demonstration of the hybridization between an electrostatic accelerometer and an atom accelerometer. We will present also simulations which quantify the benefice of hybrid technology for the knowledge of the geoid.