In-Orbit Performance of the EURECA AOCS

Abstract

The EURECA (European Retrievable Carrier) is a μ-gravity platform for multi-disciplinary space science missions and was developed by Deutsche Aerospace (DASA) under contract to the European Space Agency (ESA). On the 31st of July 92 it was launched on-board the US shuttle into a near Earth orbit and was retrieved on the 24th of June 93 in the course of the STS 57 shuttle mission. EURECA was controlled by ESA's Space Operations Centre in Germany. The attitude and orbit control subsystem (AOCS) of EURECA was developed and tested by DASA and MATRA.This paper reports about the in-orbit experience with the AOCS, which provided 3-axis stabilization for the different mission phases, including orbit transfer manoeuvres. It operated with three types of actuators (hydrazine, cold gas, magnetic torquers) and also several types of sensors (coarse and fine sun sensors, earth sensor, gyros). Examples from the Shuttle deployment, the payload operations phase under μ-gravity and the retrieval phase will be used to demonstrate the good overall AOCS performance. Special attention will be devoted to the complex, autonomous on-board failure detection which successfully mastered most of the encountered anomalies. In particular, problems relating to the tuning of the failure management system will be discussed and recommendations for potential improvements given for the benefit of other projects.