Progress in the development of a position sensor for LISAdrag-free control

Abstract

We report on progress in the development of free-fallingmoving test-masses for LISA and for the relatedtechnology demonstration mission. We present simpleformulae to evaluate the performance of the device as afunction of the various design parameters, and we comparethem with preliminary experimental results from a testprototype we are developing. Quantitative agreement isfound. Finally, we present a control law, along with aperformance simulation, for low-frequency electrostaticsuspension of the test-mass with minimal perturbation ofthe motion within the measuring frequency band.