Abstract: A spherical inertial platform has a plurality of rotary torquer units spaced around the periphery thereof for torquing the platform relative to its housing in response to stabilization signals thereby to stabilize the platform. The torquer units, which may comprise ball shaped rotors which are torqued in response to stabilizing signals fed to armatures associated therewith, provide a mechanical coupling between the housing and the platform so as to impart the stabilizing torquing forces to such platform; an effective gear ratio being provided between the torquer units and the platform.