This Small Business Innovation Research Phase I project will develop titanium Loop Heat Pipes (LHPs) that can be used in low-mass space nuclear radiators, such as the radiators currently being designed for Project Prometheus, as well as radiators for the lunar and Mars surfaces. LHPs are two phase heat transfer devices that can be embedded in radiator panels. Advanced Cooling Technologies, Inc. (ACT) has completed a radiator trade study that showed that radiators with titanium LHPs have the highest specific power in the temperature range from 300 to 550 K, increasing the specific power over heat pipe radiators by more than 1/3. The Phase I program will develop titanium/water LHPs that can operate in the low to intermediate temperature range (300 to 500K), as well as the lower portion of the intermediate temperature range (450 to 550 K). The Phase II program will develop alkali metal LHPs that can operate in the intermediate to high temperature ranges (700 to 1000 K and higher).