Ultra-Lightweight Magnesium Heat Pipes for Spacecraft Thermal Management

Magnesium heat pipes are proposed for development to replace aluminum heat pipes as the standard for spacecraft heat rejection at near ambient temperatures. Recent developments have demonstrated the potential for special magnesium alloys to be compatible with the same working fluids as aluminum, but offer a 35% reduction in mass for similar applications. A magnesium heat pipe could potentially be extruded, bent, welded, and machined by conventional methods. Phase I work will establish working fluid compatibility and demonstrate the capability to fabricate magnesium heat pipes in representative geometry. Heat pipes will be built and tested using a minimum of two representative working fluids. Phase II work will further develop these concepts into axially grooved extruded heat pipes and loop heat pipes for deployable radiators, and a space flight demonstration for Phase II prototypes is proposed.