Fast Ambient Pressure Thermal cycling of space solar array samples under equivalent AM0 illumination conditions

This paper describes the process for the design, development, manufacturing and verification of a solar simulator to be integrated in the fast ambient pressure facilities available at ESTEC's solar generator laboratory. The development of this solar simulator facility (SCID; solar cell illumination device) responds to ESTEC request to perform ambient pressure thermal cycling on solar array samples, based on triple junction solar cell technologies, under AM0 equivalent illumination during the hot part of the cycle. The SCID facilities were developed, manufactured and tested by CSL, Centre Spatiale de Liege [Belgium]. Fast thermal cycling facilities allow to perform full nominal mission life plus margins, in a reasonable amount of time, for LEO and MEO missions. The solar simulator concept designed and manufactured for the simulation of AM0 equivalent illumination and implemented in the SCID facility is presented (i.e. array of halogen and selective band LEDs) and its suitability to simulate the operation of solar cells under full representative AM0 spectral conditions is discussed. The solar simulators have been designed to provide from 1 solar constant up to 5 solar constants, with an uniformity better than ± 10%. The paper also presents the successful results of the acceptance tests performed with these SCID facilities together with the available fast ambient pressure thermal cycling chambers. These results demonstrated the robustness of the solar simulator concept to cope with the extreme temperatures during cycling and the relatively demanding pressure transients during transition between temperature extremes. Stable performance of the SCID halogen lamps and LEDs was verified during cycling as the SCID system keeps close control on their operational temperature.