Stacking test of Cluster 2 spacecraft. Photo: ESA

On March 9, after a successful stack test with its sister spacecraft (FM 8), the fourth and final Cluster 2 satellite (FM 5) completed its rigorous series of environmental tests. With the successful culmination of their assembly, integration and verification programme, the Cluster 2 quartet are now ready for transportation to Baikonur Cosmodrome, the next major landmark on the road towards launch this summer.

Driven by strict time constraints, the ESA project team, working closely with its industrial and scientific partners from all over Europe, has succeeded in meeting all of the deadlines. Just one year ago, the first spacecraft to be completed by prime contractor Dornier Satellitensysteme (FM 6) was delivered to the test facilities at IABG near Munich. It was followed at regular intervals by FM 7, then FM 8 and FM 5. All four spacecraft were briefly brought together for a press briefing at IABG in November 1999, and the test programme for the final satellite was finally completed this week.

"When we created the original timetable, we wondered if we had set ourselves an impossible task," said John Ellwood, ESA project manager for Cluster 2. "However, we have successfully delivered the spacecraft on time, within specifications and within our budget. This is a testimony to the remarkable efforts of everyone involved."

For the moment, FM 5 and FM 8 will remain in the clean room at IABG. Both spacecraft will be put into their containers, which will be closed but not pressurised, and they will then be taken across southern Germany by road convoy to Basle/Mulhouse airport on April 7. If all goes according to plan, they will be loaded onto a giant Russian Antonov cargo plane for shipment to Baikonur via Moscow on April 11.

The other Cluster 2 spacecraft - the first pair to be completed - will have already preceded them. Safely cocooned in their containers, they will be transported from the Dornier plant in Friedrichshafen. to Basle/Mulhouse airport on March 31, and wing their way towards Moscow a few days later. For them, launch will be just 10 weeks away ... and counting.