Dusty Thermal Vacuum (Dtvac) Facility Payloads Operations Under Simulated Lunar Environment

The dusty thermal vacuum (DTVAC) lunar and/or Mars environmental testing facility was designed and built to simulate the relatively extreme lunar near-surface conditions. DTVAC can accommodate test devices up to 1 x 1 x 0.9 m(3) in volume, including smaller robotic assemblies, small drill assemblies, science payloads, and surface devices such as radiators and solar panels. Depending on the testing requirements, cooling can be provided either using a recirculating chiller to about 213 K or using LN2 down to about 90 K. In addition, cooling within the DTVAC facility to 41 K using liquid helium was successfully validated on a smaller, 0.25 m x 0.25 m, platen covered with lunar regolith simulant. For the LHe platen cooling, the shroud was cooled using LN2 to provide a thermal buffer. Recently, the DTVAC facility was equipped with an additional 25 Type-T thermocouples to improve its temperature monitoring capabilities, and a 1 to 200 amu residual gas analyzer (RGA) in order to identify the molecular composition of any outgassing from articles under test. A LN2-cooled cold finger was also installed to assist the system vacuum pump down and to facilitate the study of in-situ volatiles. This paper reviews the DTVAC upgrades, functionality calibrations, and summarizes its current capabilities.