This paper describes an advanced technology figure control system for a generic class of large space based segmented reflector telescopes. A concept definition study was recently carried out at the Jet Propulsion Laboratory to develop the sensing and control mechanization for the actively controlled primary reflector. The reflector segments are made up of hexagonal composite panels individually pre-assembled to a panel control module that contains the sensing, actuation and control electronics hardware for each segment module or "unit cell." Unique features of this integrated segment control module include a completely determined kinematic mounting to the underlying truss structure, inherent attenuation of truss vibrations, prevention of load transfer to mirror panels and reaction moments to the truss nodes, three degree-of-freedom (piston and tilts) active position control, and passively restrained in-plane lateral and rotational motion. The unit cell physical architecture also provides a reference station for interferometric sensing of relative motion between adjacent mirror segments, a mounting for linear electrodynamic actuators, and forms a robust, readily transportable unit which can be attached to the truss during space assembly without risk of damage to the figure control mechanisms and mirror segment. Performance requirements are derived in part from the Large Deployable Reflector, which is a representative mission, and error allocations are made which consider mirror panel surface errors, position measurement and figure estimation, and position control of both quasi-static and dynamic disturbances. Major technology and design motivations for selection of sensing, actuation, and mechanism approaches result from the high precision and very low mass and power goals for the reflector system. Finally, analysis of performance, mass, and power for the unit cell mechanization are shown to be compatible with these objectives.