REDUCED-MASS RADIATOR USING HIGH-TEMPERATURE LOOP PIPES

The innovation in the proposed program is the replacement of conventional heat pipes in the current design with Russian-designed and patented loop heat pipes. This significantly reduces the radiator mass, by eliminating the need for a wick in the adiabatic and condenser sections of the loop heat pipe. Loop heat pipes can also withstand a greater gravitational head during ground testing. A limitation for heat pipes on earth and in space is the heat transport capability under the influence of an opposing acceleration: gravitational acceleration on earth, and an induced acceleration resulting from spacecraft maneuvers on-orbit. In some cases, the heat pipe system must be operated on earth gravity-aided (evaporator down). The proposed program will fabricate and test a high temperature loop heat pipe, using an alkali metal or other suitable working fluid and examine the effects of loop heat pipes on overall radiator mass.