Development of an efficient, highly uniform Sun Simulator for optical space instrument calibration

Abstract

In space Earth Observation related projects, Sun Simulators are regular used for on-ground calibrations of the flight instruments. Instrument radiometric calibration is established by illuminating the on-board diffuser(s) via the Sun port in irradiance configuration and an external OGSE calibrated diffuser for the radiance configuration via the Earth Port. Usually, Sun Simulator designs are complex containing multiple coated mirrors, and its implementation requires large volume and mass. The paper will present an elegant and innovative concept of building such a Sun Simulator using minimum elements. The new concept consists of three major units: the illumination unit, the diffuser unit and the collimator unit. All units have been purchased, mounted on an optical table and aligned. Finally, preliminary performance tests of the Sun Simulator Breadboard are presented. The Breadboard proves the concept and also allows scaling to different instrument needs.