CAPACITIVE SENSING FOR DRAG-FREE SATELLITES

We report the key results of a study of the optimization of capacitive sensing for LISA. This work was a component of an ESA study into drag -free satellite control. We discuss the problems associated with the c apacitive sensing and control of a proof mass which is electrically is olated and develop models for candidate non-resonant and resonant dete ction schemes. We calculate acceleration noise assuming an ideal contr ol system whose only noise sources are the capacitive sensors and actu ators. On the basis of this model it appears that the design goal of a cceleration noise for the LISA mission is achievable using both resona nt and non-resonant detection schemes. The residual acceleration noise on the proof mass is dominated by oscillator noise which produces for ce and displacement noise due to asymmetries in the electrode capacita nce values and bridge components.