Advanced Cooling Technologies, Inc. proposes to develop a hybrid cooling loop technology for space thermal control. The proposed technology combines the high heat flux performance of active cooling loops with the effective fluid management of passive cooling devices. The result is a simple, robust and high performance cooling technology that allows maximum degree of packaging flexibility. Phase I has demonstrated the technology in cooling high heat fluxes in excess of 350W/cm2 from large areas in excess of 4cm2 with low thermal resistances (0.008 to 0.065o
C/W/cm2). The prototype hybrid loop was tested at various orientations to verify its robust operation. The Phase I results indicated that the hybrid loop is capable of substantially outperforming the state of the art heat pipes, loop heat pipes and spray cooling systems. The principal Phase II objectives are to develop advanced performance features and qualify the hybrid loop technology for space thermal control through testing of multiple generations of prototypes and ground qualification testing of engineering units. The Phase II results will elevate the technology to a TRL 6: Prototype demonstration in a relevant environment. The follow-on Phase III will conduct flight qualification testing of the technology to address micro gravity operation issues.