The launches of four European Space Agency DaimlerChrysler Aerospace-built Cluster II science satellites has been delayed by the discovery of a potentially leaking thruster on the spacecraft. The launch of Clusters in pairs on two Starsem Soyuz Fregat boosters planned for June and July have been set back to August at the earliest.

The thruster problem is affecting several European communications satellites manufactured by Matra Marconi Space and Alcatel Space and those supplied with similar thrusters from DaimlerChrysler Aerospace, Bremen.

The insurance community has insisted no satellites be launched until the thruster system has been fully tested. The problem centres on the possible leak of fuel when the thrusters are fired. It is believed that there are tiny amounts of fuel leaking from thruster joints when short firings are made to keep the spacecraft on station.

As a result, the Eutelsat W4 communications satellite will not be launched in May on the maiden flight of the International Launch Services Atlas IIIA. The Ariane 5 launches of Astra 2B, Nilesat 102, Eutelsat W1R and Eurasiat 1 are also on hold.

It is understood that not all satellites fitted with the German thrusters may be affected.

Source: Flight International