ONERA accelerometers for NGGM and for future gravity missions.

The 2017-2027 Decadal Survey for Earth Science and Applications from Space has identified the Targeted Mass Change Observable as one of 5 Designated Mission. In Europe, the development of the ESA Next Generation Gravity Mission is on progress, with the start of the Phase B in 2024.

These missions will continue the observation provided by GRACE and GRACE-FO. In these missions and the future concepts, the accelerometer provides either the gravity signal in a gradiometer configuration (GOCE type mission), or the non-gravitational acceleration to be suppressed to the ranging measurement between two satellites (GRACE-type mission).

In the frame of NGGM activities with ESA, Onera is developing the new accelerometer MicroSTAR, a high accuracy accelerometer with 3 sensitive linear acceleration measurements as well as 3 angular acceleration measurements for the attitude control or reconstruction. PDR of the accelerometer chain has been done at the end of year 2024 and CDR of the accelerometer sensor head will be held in May 2025.

ONERA have procured the accelerometer for all the previous gravity missions (GRACE, GOCE, GRACE-FO). In parallel, ONERA work to improve the scientific return of the instruments for the future missions:

• a miniaturized version of MicroSTAR, the CubeSTAR accelerometer, is developed with internal funding. CubeSTAR is adapted for constellation or nanosat,
• An other way is to improve the low-frequency noise of the accelerometer, by hybridization of electrostatic accelerometer with cold atom interferometer.

The presentation will present the status of the MicroSTAR development, and will detail the development of future instruments.