Cluster commissioning continues to boom
20 October 2000Now half way through their complex commissioning campaign, the Clusterquartet are well on their way to becoming operational.
Members of the Cluster Science Operations Working Group - including principal scientific investigators and representatives from ESA, ESOC (the European Space Operations Centre) and JSOC (the Joint Science Operations Centre) - gathered this week in Darmstadt, Germany, to discuss the current status of Cluster's exciting mission to explore the magnetosphere.
Deputy Project Scientist Michael Fehringer reminded the audience that 21 of the 44 science instruments have already been fully commissioned, including all of the wave experiments on Rumba and Salsa, all four FGM instruments, and the three particle experiments on Samba and Tango.
The commissioning of a further 10 instruments has also begun, leaving only 13 that have still to be started.
"We have to stagger the commissioning of each instrument so that we have some data from all of the 11 separate experiments early in the mission," said Cluster Project Scientist, Philippe Escoubet. "We do this because we cannot commission the wave experiments on a satellite at the same time as its particle instruments, since the satellite's spin rate changes during deployment of the wire booms."
As a result, the systematic deployment of the 41 metre-long wire booms that are used by the Electric Field and Wave (EFW) experiment was completed first on Rumba and Salsa, and is now well under way on Samba. Boom deployment on the fourth spacecraft, Tango, is scheduled to take place between 25 October and 16 November.
Meanwhile, the mini-flotilla of spacecraft continues to orbit the Earth once every 56 hours, with an average separation distance of only 600 km. Once some minor orbital manoeuvres have been undertaken in December, they will be in the tetrahedral configuration to begin detailed observations of the planet's magnetic cusp regions.
"We are very pleased with the way this difficult commissioning phase has been progressing," said Philippe Escoubet. "Every day we are receiving about 20 hours of telemetry data from the spacecraft via two antennae at VILSPA in Spain and the Deep Space Network stations in Canberra and Goldstone."
"There have also been two successful dry runs of the communication system that transmits commands from JSOC in the UK to ESOC in Germany. Everyone at ESOC, JSOC and in the PI teams is working really hard to get all four spacecraft up and running by the end of the year, so that we can start the full scientific programme."