The Aristoteles/Gradio program aim was to measure the gravity field gradient at the altitude of an orbiting satellite. This observable is much more sensitive to short wavelengths than the geoid is. The reason is that the gravity potentiel ("the geoid") suffers an attenuation with altitude : potentiel is proportional to 1/r where r is the distance from the source mass) and wavelength : at altitude 0, potential is proportional to 1/l² (Kaula's law), when it's second derivative (the gravity gradient) only suffers an attenuation with altitude.
The instrument to measure this gravity gradient is made of pairs of accelerometers, set along the 3 perpendicular directions in space, centered on the satellite center of mass.
The STAR accelerometers were designed by ONERA.
Unfortunately, in spite of it's great interest and advanced techniques for the determination of the Earth gravity field, the system was never launched....

but, quite recently, the CHAMP satellite was launched by GFZ/CNES/NASA with more or less the same objectives.