Alternative method of solar simulation for thermal vacuum tests of spacecraft

Solar simulators based on gas-discharge xenon lamps, used to obtain the thermal state of objects for thermal vacuum testing of spacecraft, are one of the key, most complex and energy-consuming elements of test equipment. Complexity of the optical system, the large number of optical elements, the need for constant monitoring of their condition, tuning and adjustment by highly qualified personnel significantly complicate obtaining of required luminous characteristics, mainly spatial uniformity of irradiance. Another common drawback is their low energy efficiency, which does not exceed 10 %. We proposed an alternative method of solar simulation using solid-state luminous sources – high-efficiency LEDs, with their placement without a bulky and complex optical system directly in a thermal vacuum chamber. At the same time, one of the most difficult problems of adapting to the conditions of thermal vacuum tests is to provide the necessary luminous characteristics. The required wavelength range, spectral match is obtained by combining assemblies of high-efficiency LEDs of six different wavelengths and halogen lamps. We carried out a number of experiments, including measuring the luminous characteristics of alternative luminous sources and mathematical modeling of the matrix emitter. As a result, the possibility of using the proposed method for thermal vacuum tests of spacecraft was confirmed; the luminous characteristics of the model meet the requirements, and in terms of uniformity of irradiance and energy efficiency, they significantly exceed those of traditional solar simulators.