Gøsta Thuesen

Radiation impacts on star-tracker performance and vision systems in space

Abstract CCD-chips are widely used in spacecraft applications, due to their inherent high resolution, linearity, sensitivity and low size and power-consumption, and irrespective of their rather poor handling of ionizing radiation. One of the experiments onboard the Teamsat satellite, the payload of the prototype Ariane 502, was the Autonomous Vision System (AVS), a fully autonomous star-tracker with several advanced vision features. The main objective of the AVS was to study the autonomous operations during severe radiation flux and after appreciable total dose. The AVS experiment and the radiation experienced onboard Team-sat are described. Examples of various radiation impacts on the AVS instrument are given, and compared to ground based radiation tests.

The determination of the attitude and attitude dynamics of TeamSat

Abstract The second qualification flight of Ariane 5 was launched from the European Space Port in French Guiana on October 30, 1997. It carried on board a small technology demonstration satellite dubbed TeamSat into which five experiments, proposed by various universities and research institutions, were integrated. Among them, the Autonomous Vision System, AVS, a fully autonomous star tracker and vision system. This paper gives a short overview of the TeamSat satellite design, implementation and mission objectives. The AVS is described in more details. The main science objectives of the AVS were to verify, in space, multiple autonomous processes intended for spacecraft applications such as autonomous star identification, attitude determination and identification and tracking of non-stellar objects, imaging and real-time compression of image and science data for further ground analysis. AVS successfully determined the attitude and attitude dynamics of TeamSat.