On-ground investigation of space accelerometers noise with an electrostatic torsion pendulum

A torsion pendulum has been used to measure very weak forces that limit the resolution of highly sensitive space accelerometers. A new method is described to measure damping with a feedback loop. The main results are (i) an upper limit to time evolution of contact potential differences inside electrostatic space accelerometers, (ii) the stiffness and damping from a very thin conducting wire, and (iii) an additional damping from unknown source. Consequences for space accelerometers design are derived.