# Hybrid Electrostatic-Atomic Accelerometer for Future Space Gravity Missions
## 4 Conclusions
To further validate the feasibility of such a hybridized configuration, some experimental demonstrations were conducted with a lab hybrid prototype consisting of a cold atom gravimeter and a dedicated ground electrostatic accelerometer. Acceleration measurements were obtained following a hybridization scheme, highlighting the interest of EA hybridization with a CAI. The potential of the EA instrument to cancel satellite rotation impact on the CAI contrast was demonstrated by controlling the electrostatic proof-mass acting as the CAI reference mirror. Experimental demonstration of rotation compensation with a 85% efficiency of contrast recovery was performed. Further experimental activities are necessary to explain the non-complete contrast recovery and to study the impact on the acceleration error budget. Finally, the ability for the EA to compensate the satellite rotation and to simultaneously allow a precise acceleration measurement should be studied experimentally as a next step. To evaluate the potential of the integration of a hybrid atomic-electrostatic accelerometer in a satellite, a preliminary design was elaborated. The SWaP of such a design was given along with an associated error budget. All these estimations should be further consolidated with the elaboration of a more detailed architecture and by addressing in a more exhaustive way all the effects that could have a detrimental impact on the CAI output. More particularly, the impact of wavefront aberrations and methods for satellite rotation compensation should be further analyzed, whether with simulation tools or with experimental demonstrations. Considering a CAI based on a molasses source, a hybrid instrument of 109 L, 75 kg and 145 W should be feasible with a level of performance in the range of 10\({}^{-10}\) m\(\cdot\)s\({}^{-2}\), the impact of wavefront aberrations assumed here mitigated. This reported study constitutes a preliminary analysis of an original accelerometer design for future space gravity missions. This configuration based on the emerging cold atom technology seems promising for performance improvements and requires further investigations thanks to simulations or experimental activities to consolidate all the potential envisioned for this technology. Conceptualization, N.Z., B.C., Y.B., A.B., P.A., T.G., R.P. and O.C. ; methodology, N.Z., B.C., E.H. and P.-A.H.; software, N.Z., B.C., E.H., P.A., T.G. and R.P. ; validation, N.Z., B.C., Y.B., A.B., P.A., T.G., R.P., I.D. and O.C. ; formal analysis, N.Z., B.C., P.A., T.G. and R.P. ; investigation, N.Z., P.-A.H., N.M. and C.B. ; resources, N.Z., B.C., V.L., C.B., T.G. and R.P. ; data curation, N.Z., B.C., V.L., P.A., T.G. and R.P. ; writing--original draft preparation, N.Z., B.C., V.L., E.H., P.A., T.G. and R.P. ; writing--review and editing, N.Z., B.C., Y.B., A.B., P.A., T.G., R.P. and O.C. ; visualization, N.Z., B.C., V.L., E.H., P.A., T.G. and R.P. ; supervision, N.Z., B.C., T.G., R.P. and O.C. ; project administration, N.Z. ; funding acquisition, N.Z. and A.B. All authors have read and agreed to the published version of the manuscript. This research was performed in the framework of the study \"Hybrid Atom Electrostatic System Follow-On for Satellite Geodesy\", Contract No.4000122290/17/NL/FF/mg, funded by the European Space Agency (ESA). The Ph.D. study of [PERSON] is co-funded by ESA and ONERA. Not applicable. We would like to thank [PERSON] (ONERA) for his early participation in the realization of the EA ground prototype and [PERSON] (ONERA) for her assistance during the experimental activities. We thank also [PERSON] (ESA), [PERSON] (ESA), and [PERSON] (ESA) for fruitful discussions during the course of the study. The authors declare no conflict of interest. The following abbreviations are used in this manuscript: