Traditionally, thermoregulation of space walking astronauts has been achieved by the sublimation of water to the vacuum of space. Future missions call for the need to achieve robust closed-loop thermal control to reduce or eliminate extravehicular activity (EVA) burden on consumables. The current leading concept to achieve closed-loop thermal control is the Space Evaporator-Absorber-Radiator (SEAR). The SEAR is nearly capable of achieving the desired non-venting capability; however, carried water mass for evaporation will still be comparable to a sublimator-based system. Evolution from systems which leverage sublimation or evaporation of water as the primary heat rejection mechanism to a system which directly leverages the local radiation environment may provide another means of achieving robust closed-loop space suit thermal control at a reduced system mass. Previous EVA thermal control investigations that utilize radiation have generally limited radiator surface area to the available size of the portable life support system backpack: about 0.85 m2. The utilization of a full suit flexible radiator increases this area by a factor of ~4 for traditional gas pressure suits and ~2 for the advanced mechanical counter pressure suit concept. Radiator heat dissipation capacity is also dictated by radiator temperature, radiator surface properties (e.g. emissivity, absorptivity) and the local thermal environment. As such, suit radiator surface temperature should be maximized to the extent possible for the flexible radiator architecture to be feasible under most circumstances. Here we present radiator surface temperature guidelines for the full suit flexible radiator architecture in steady-state environments. Results identify favorable thermal environments in which a full suit flexible radiator can reject a nominal 300 W metabolic heat load produced within a space suit.
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