Modeling the Human Thermal Balance in a Space Suit using a Full Surface, Variable Emissivity Radiator

Date

2015-07-12

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Publisher

45th International Conference on Environmental Systems

Abstract

Space suit thermoregulation has traditionally been achieved by sublimating water to space. Incorporation of a full suit radiator using variable emissivity electrochromic devices is one proposed alternative for reducing or eliminating the water mass loss incurred for cooling by sublimation. This concept allows the majority of a space suit’s outer surface area to operate as a radiator, while the electrochromic’s controllable surface properties enable variable heat rejection rates. Internal heat loads are balanced to the total radiated energy by selecting the emissivity of the electrochromic surfaces. Steady-state evaluations of this concept indicate that high metabolic loads and/or hot lunar surface locations can exceed the radiative heat dissipation capacity, however, the net impacts of dynamic internal and external environments on an astronaut’s thermal condition have not yet been fully considered for this application. Here we present an evaluation method for determining transient environmental thermal impacts on a simulated human in a space suit using variable radiative cooling. Four test scenarios are used to illustrate the utility of the method for an astronaut in a simplified lunar pole environment. The scenarios considered were chosen such that comfort requirements could be maintained throughout the duration of each of the simulations. Overall, the approach described here can be used in future investigations to advance the characterization of the electrochromic suit radiator architecture’s working environment envelope.

Description

Bellevue, Washington
Christopher J. Massina, University of Colorado, USA
James A. Nabity, University of Colorado, USA
David M. Klaus, University of Colorado, USA
The 45th International Conference on Environmental Systems was held in Bellevue, Washington, USA on 12 July 2015 through 16 July 2015.

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