NASA's future remote sensing science missions require advanced thermal management technologies to provide effective cooling for multiple instruments and reject heat through multiple radiators. Two-phase pumped loops are an ideal solution for these applications. A critical need for these pumped loops is a refrigerant pump that reliably circulates very slightly subcooled liquid refrigerant in the loop. To this end, Creare proposes to develop an efficient, vibration-free pump that has design features to prevent cavitation in the pumping chamber and in the hydrodynamic fluid bearings, and thus enables the pump to achieve a long service life. The development of the refrigerant pump will be built on Creare's proven high-speed turbomachine technologies for space applications. In Phase I, we will prove the feasibility of the refrigerant pump by developing a preliminary pump design, predicting its overall performance, and demonstrating its key features by testing. In Phase II, we will optimize the pump design, fabricate the pump, demonstrate its steady state and transient performance in a representative pumped loop, and deliver it to NASA JPL for further performance evaluation.