Main technical features and performance evaluation of a miniaturized test system for star trackers

The validation of the correct functioning of star trackers is a crucial step for the success of any space mission. In recent years, there has been an increasing interest for the development of miniaturized, light-weighted test systems to be installed directly on the star tracker, opening the way to the test of completely assembled, on-board attitude sensors in pre-launch environment. Here we present the main technical characteristics of a new prototype, the MINISTAR, recently developed by a consortium of Italian enterprises and the Applied Physics Institute of the National Research Council. Besides its main technical features, here we present the results of a set of tests for its performance evaluation, with particular reference to its radiometric and geometric calibration in the laboratory. The MINISTAR can generate synthetic images of dynamic star fields for the simultaneous test of multiple star trackers (up to three head devices). The generation of dynamic star fields in a realistic scenario also includes large objects, such as the Sun or the Moon, and disturbances (e.g. cosmic rays and stray light effects). Thanks to its reduced dimensions and weight, the MINISTAR is suitable for the installation on the star tracker's baffle. Special attention has also been paid to the use of materials and technologies that could be compliant for vacuum operation in the future. Thanks to the design and construction of an interchangeable mechanical interface, the MINISTAR is compatible with the majority of star trackers available on the market.