Experimental and analytical assessment of space thermal and vacuum environment simulation requirements.

A review of space simulation requirements is made lo show that a thorough analysis of test planning and facility selection can result in less expensive component and systems testing. Representative orbital flight data are used to show how well present analytical procedures predict the vehicle's response to the space thermal environment. Arguments are given for the use of similar depth in analyzing facilities and space simulation requirements. A comparison is made of several methods now in use for simulating the space thermal environment •within large vacuum chambers. Spectral intensity of a tungsten filament-quartz tubular lamp has been determined and is presented as a function of voltage. A procedure is developed whereby a good simulation of vehicle-space thermal energy exchange can be obtained without duplicating the solar spectrum in the energy source. Equations for the vehicle-environment energy balance are discussed for vehicles tested with surface conditions both like and unlike the flight configuration. Spectral absorptivities of several thermal control surfaces are presented to help assess the influence of the source intensity spectral shift and how this is compensated for.