The 4 Cluster 2 spacecraft at IABG. Photo: ESA

The Cluster 2 Flight Acceptance Review Board, which was chaired by European Space Agency Director of Science, Professor Roger Bonnet, and co-chaired by ESA Director of Strategy Jean-Jacques Dordain, met at the Agency's Paris Headquarters on March 29 to carry out a detailed examination of all aspects of the Cluster 2 mission.

The panel of experts listened to a number of presentations covering key aspects of the mission. They included an overview of the spacecraft assembly and test programme by prime contractor Dornier Satellitensysteme, results from the recent Cluster 2 Mission Validation Flights which tested the newly developed Fregat upper stage on the Soyuz rocket and status reports from all of the Scientific Principal Investigators about the four sets of 11 instruments which will investigate the Earth's magnetosphere.

Also presented to the Flight Acceptance Review Board were the results of recent reviews involving the ground segment and data distribution. These centred on activities at the European Space Operations Centre (ESOC) in Darmstadt, Germany, and the Joint Science Operations Centre (JSOC) at Rutherford Appleton Laboratory in the UK.

The Review Board expressed full satisfaction with the status of the four Cluster 2 spacecraft and endorsed the positive findings of the Review Team, who had gathered for a week-long colocation at Dornier premises in Friedrichshafen (D) the previous week. The Board also shared the Project concerns over a generalized problem of the propulsion system of the spacecraft, which is currently affecting several of them, both in-orbit and about to be launched.

The Project team has proposed a course of action, which has been fully endorsed by the Board, that will lead to a final decision concerning the suitability of the current propulsion system for the Cluster mission.

Board members consequently recommended a delay of the shipment of the four spacecraft to Baikonur Cosmodrome, until investigations are completed.

More detailed information on the results of the investigation and its impact on the mission will be issued as available.