Optical system of perspective led-based solar simulator for spacecraft ground testing applications

The transition to the production of new generation spacecraft requires a significant improvement in the methods and means of ground experimental testing, improving the accuracy of test equipment. One of the basic and most complex elements of the test equipment used in complex thermal vacuum testing of spacecraft is the solar simulator. Currently, a promising direction is the construction of solar simulators based on highly efficient LEDs that have significant advantages over traditional sources. Design of a highly efficient and at the same time compact optical system summing the emission of many individual LEDs of the LED array over the spectrum, angle and area into a uniform light field with minimal losses is the one of base tasks in development of adapted for ground testing spacecraft solar simulator. The article analyzes the mathematical modeling results of LED solar simulator's light source on the example of several models with different numbers of LEDs, both without optical elements, and with various primary optical elements. Results it follows that the LED solar simulator radiation must necessarily have, at a minimum, a primary optical system. The influence of the number, type and size of the primary optical elements in the matrix on the characteristics of the light flux is determined. The combined use of primary and secondary optical systems leads to a further light characteristics improvement of the LED solar simulator, but at the cost of some reduction in overall efficiency. In general, the characteristics of the modeled light source correspond or closely approach to required ones, which indicates that it is possible in principle to create a solar simulator based on LED sources for ground testing of spacecraft.