Volatiles Investigating Polar Exploration Rover (VIPER) System Integrated Thermal Vacuum Test Planning and Preparation

The Volatiles Investigating Polar Exploration Rover (VIPER) is a NASA designed and built rover going to the lunar south pole to drill for ice and other volatiles. During VIPER’s mission the rover will experience a wide range of temperatures: high temperatures while roving in the sunlight and low temperatures while drilling in permanently shadowed regions or surviving hibernation. To withstand these temperatures and perform drilling, roving, and science on the lunar surface, the team designed a thermal management system made up of loop heat pipes, constant conductance heat pipes, radiators, multilayer insulation (MLI) and thermal control valves. For verification of the thermal system performance, a series of tests were planned in ambient and vacuum environments. One of these tests was a system level thermal vacuum (TVAC) test; this test was a culmination of years of work from the design of the rover thermal system, to how to test the thermal management system (TMS), and how to collect data for post-test model correlation. TVAC was conducted at Johnson Space Center (JSC) in Chamber A. The test took the rover through hot and cold cycles, hot and cold thermal balance, and simulated hibernation. The chamber simulated a cold environment for VIPER to experience a hibernation while a radiation enclosure built around the rover simulated the hot environments. The TVAC test was planned to capture data to correlate thermal models and show VIPER functionality over a range of environments expected during the mission. This paper will go over the process and design considerations involved with preparing for the system integrated thermal vacuum test.