As in STEP, 1-D motion forbids fast spin and makes passive self centering impossible (active centering by off-setting the servo loops); balancing the restoring force of the gold wire requires large active forces continuosly applied to the test masses
	Each test cylinder is suspended independently, has its own capacitance read out and its own servo loop to keep itself “motionless”. A small signal is extracted as the difference of two large ones   Þ  not a differential instrument