A Satellite Retires - The ERS-2 Deorbiting In Summer 2011

The ERS-2 deorbiting started on 6 July 2011 after 16 years of successful operations of this ESA Earth Observation satellite. Many orbit lowering maneuvers were necessary to reach the target altitude of 570 km. Apart from the late failure of a backup gyro, which had no impact on the overall activity, all subsystems onboard performed perfectly. Although not originally foreseen in the early mission days, the later decision to deorbit ERS-2 was mostly compliant with international guidelines and ESA requirements on space debris mitigation and ensured a re-entry of the satellite in less than 25 years. The ERS-2 deorbiting was the first such activity of an ESA polar orbiting satellite. It was started with an initial re-orbiting in Feb 2011 in order to achieve a 3-days repeat cycle for scientific reasons for a period of 3 months. This orbit change served as a dress rehearsal for the later orbit lowering maneuvers and platform operations. The deorbiting related operations were implemented at ESA’s Operations Centre ESOC in Darmstadt, Germany, in close collaboration with the Mission Management, the ESTEC based Post Launch Support Office and industrial support by ASTRIUM Toulouse. This included the definition of the overall operations concept, the maneuver strategy, on-board configuration trade-offs, contingency plans, new and modified procedures, extensive simulation and training sessions and an extended ground station network. This paper summarizes these activities together with the deorbiting background and objectives, timeline and results.