Lightweight, Flexible, and Freezable Heat Pump/Radiator for EVA Suits

We have completed preliminary tests that show the feasibility of an innovative concept for a spacesuit thermal control system using a lightweight, flexible heat pump/radiator. The heat pump/radiator is part of a regenerable LiCI/water absorption cooling device that absorbs an astronaut's metabolic heat and rejects it to the environment via thermal radiation at a relatively high temperature. We identified key design specifications for the system, demonstrated that it is feasible to fabricate the flexible radiator, measured the heat rejection capability of the radiator, and assessed the effects on overall mass of the PLSS. We specified system design features that will enable the flexible absorber/radiator to operate in a wide range of space exploration environments. The materials used to fabricate the flexible absorber/radiator samples were all found to be low off-gassing and many have already been qualified for use in space. Fabrication samples demonstrated hermetic seals and excellent structural strength, holding internal pressures greater than 35 kPa (5 psi) with no deformation or damage. A 55 W-hr proof-of-concept absorber successfully demonstrated thermal regeneration and provided refrigeration at a temperature of 19°C while rejecting heat at a temperature of 50°C. This technology promises to enable a non-venting, freeze-tolerant, lightweight radiating system for EVA suits on future space exploration missions.