With its family of ultra sensitive accelerometers used in Earth geodetic missions, the Onera team has accumulated these last years, the technical experience to propose a new concept of instrument for planetary missions: the GREMLUN gradiometer. Based on the principle of a planar configuration with four test masses at the corners of a square, the instrument is optimized to comply with the limited interface budgets of planetary missions. Within less than 10 kg, 10 liters and 10W, the instrument measures the differential acceleration along two axes and the angular acceleration about the third one. By taking advantage of the null trace property, the 3 diagonal components of gravity gradient tensor will be determined with an accuracy of 0.1Eoetvoes. Using the improved technologies of the electrostatic space accelerometers, the GREMLUN instrument can claim a level of TRL sufficiently high to be integrated after reduced additional development in the payloads of the next planetary and small bodies exploration. In particular, the precise knowledge of the Near Earth Objects' gravity properties can be of the most important interest to accurately foresee the asteroid trajectory after resonant flyby with the Earth as in the case of the Apophis encounter in 2029.
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