XMM controlled as if in orbit
10 August 1999Controlling XMM from a distance as though it were in space: that wasone of the main objectives of the System Validation Test (SVT) whichtook place at the end of July. The spacecraft, which was located inESTEC Noordwijk, the Netherlands was actively controlled by the XMM Mission Operations Centre (MOC) at ESOC in Darmstadt, Germany.
The first such SVT test took place last March and validated the communications aspects, the ability of the MOC to remotely establish contact with the spacecraft and to conduct realistic typical flight operations procedures. The recent SVT-2 test was the first with the fully integrated spacecraft and the first to involve all major elements of the XMM ground segment, including the XMM Science Operations Centre (SOC).
During ten intensive working days between 20th-30th of July, all major aspects of the XMM spacecraft and its complement of science instruments were excercised in real-time as if XMM was already in orbit.
The test configuration was fully representative of the in-orbit configuration. It mobilised the XMM satellite Assembly, Integration and Verification (AIV) teams from ESTEC and prime contractor Dornier, the Experiments Operations teams, and the Flight Control and ground segment support teams at ESOC. In all some 30 highly motivated people were on the bridge!
On the spacecraft side, the fully assembled XMM, which had passed its acoustic acceptance tests on 6th of July, had all its subsystems and scientific experiments connected. On the ground segment side, the XMM Mission Operations Centre was fully operational, composed of its communications network, the Mission Control Systems to command and monitor the satellite, and major components of the XMM Science Operations Centre, which prepare scientific observations and gather and process the science data from the on-board cameras.
All objectives of this SVT-2 test were fully met and the spacecraft is now being readied for shipment to French Guiana next month. On arrival, the third and final SVT will be conducted, again from ESOC, to finally confirm the ability of the ground segment to take full control of the spacecraft in flight.
The lessons learned during SVT are valuable contributions to the preparation for the forthcoming XMM mission simulations programme and in the run up to launch, which is set for the 15th December 1999.