Thermal Vacuum Testing of a VIPER Loop Heat Pipe

NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) was designed operate in the extreme thermal environment of the lunar south pole. The rover uses Loop Heat Pipes (LHP) as the primary device to transport heat from the Warm Electronic Box (WEB) to the radiators. An Engineering Design Unit (EDU) LHP has been tested under Thermal Vacuum (TVAC) environment to characterize its performance, assist on design of the flight hardware, provide thermal-power data for modeling correlation, and facilitate console operator training. The effect of gravity, 1g versus the lunar 1/6 of Earth gravity, thermal loads, sink temperatures, and heating choreography on the steady state LHP performance were some of the design parameters evaluated. Transient behaviors like LHP startup, and LHP shutdown, were also investigated. This technical presentation will summarize the instrumentation, the temperature and power measurements, and the observed LHP dynamics through the different TVAC test segments.