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 descr ibed to measure damping with a feedback loop. The main results are (i) an u pper limit to time evolution of contact potential differences inside electr ostatic space accelerometers, (ii) the stiffness and damping from a very th in conducting wire, and (iii) an additional damping from unknown source. Co nsequences for space accelerometers design are derived. (C) 2000 American I nstitute of Physics. [S0034-6748(00)03401-8].