ASTRO 15 Star Tracker Flight Experience and Further Improvements Towards the ASTRO APS Star Tracker

Abstract

Since 2003 the autonomous star tracker ASTRO 15 successfully operates in-orbit on a large variety of different missions like telecommunication and Earth observation. JenaOptronik received from non-classified programs real time telemetry data packages of ASTRO 15 operating under real in-orbit conditions. These valuable data have been analyzed and evaluated down to the specification requirements like attitude noise, low spatial frequency error and high spatial frequency error. As expected the accuracy achieved under in-orbit conditions is better than that derived from ground based measurements in the laboratory or on real sky. The paper presents the ASTRO 15 performance and compares that with the ground based verification measurements and the predicted performance from the early error budget analysis. Today Astro 15 benchmarks the state of the art off the shelf autonomous star tracker technology which operates successfully in-orbit. The next generation of star trackers will be based on active pixel sensors (APS) replacing the charge coupled devices (CCD) for performance and robustness improvements. Jena-Optronik finished in a prosperous manner the development of an APS based star tracker “ASTRO APS”. In the last chapter of the paper we show how the ASTRO 15 heritage and the lessons learned have been introduced in the ASTRO APS design. The highlighting features mentioned here are the autonomous background noise and white spot correction and the self calibration technique.