Solar simulator absolute irradiance radiometry

One of the most challenging aspects of qualifying a spacecraft for flight is ensuring that it can both survive and perform in a vacuum and under the intense solar illumination conditions in space. In order to do this ESA has several solar simulators which can provide simulated solar illumination beams of different diameters and intensity under vacuum. The output irradiance of these beams needs to be known and calibrated accurately to ensure that both the test levels are correct and can be used for the correlation of the results with predictions to verify compliance of the thermal performance of the satellite (or system) prior to flight. With two types of absolute radiometers available to us (PMOD & Kendall) we can perform these calibrations in house at ESTEC.