Single crystal piezoelectric actuators are proposed to enable large stroke, high precision, shape control for cryogenic lightweight deployable membrane mirror structures for future NASA Science and communications applications. Piezoelectric properties of PMN-PT single crystal at a temperature of 4 K will be investigated. Compact piezo linear motor utilizing PMN-PT single crystal driver will be assembled and characterized at temperatures of 4K-300K. Specific goals for cryomotor are: maximum stroke >100 mm, maximum driving force ~10 N, response time ~ ms, positioning resolution ~50 nm, operating temperature of 4K-300 K, total mass <50 g, and power consumption <1 W. The deployment structure design and the stroke, force required for membrane mirror deployment will be identified in the phase I, and a 25 mm aperture membrane mirror deployment concept demonstration will be conducted in Phase I. At the conclusion of the Phase I program the feasibility of single crystal cryomotor for deployable membrane mirror will have been demonstrated. In Phase II, optimized single crystal piezoelectric actuators will be integrated into a 3 m deployable membrane mirror structure and delivered to NASA Labs for evaluation.