A torsional-type thrust stand has been designed in order to measure precisely the impulse bits produced by low-power pulsed plasma thrusters. The stand is capable of measuring impulse bits ranging from 10 to 1,000 μNs in vacuum conditions. Investigations concerning extremely low impulse measurement have encountered difficulties in the past due to undesired vibrations of the measuring facility. The relation between the background noise and the excited vibrations to the thrust stand is considered and it is shown that an optimum damping ratio exists which provides a maximum SN (signal-to-noise) ratio.