A laboratory prototype of GRS was built in Europe and has been tested in the torsion pendulum facility at the University of Trento. Using an ultra-sensitive torsion pendulum, the prototype demonstrated a residual acceleration of 5 x 10-11 m/s2 Hz1/2. This level of disturbance was due to thermal motions of the apparatus and not limitations of the GRS. Additional analysis and measurements of specific disturbance effects indicate that the design of the GRS meets the LISA requirements.
From LISA TRIP Review (2002) (Fig D-8)