Press Release

XMM flying beautifully

By SpaceRef Editor
December 20, 1999
Filed under

The European Space Agency’s new X-ray space telescope has reached its operational orbit less than a week after being launched from Kourou on 10
December. The XMM spacecraft, which is being controlled by teams at the ESA’s Space Operations Centre, ESOC in Darmstadt Germany, is functioning

The early orbit phase came to an end on 16 December after XMM had been manoeuvred to its final orbit. This required four firings of its thrusters, on
successive passages at apogee, in order to increase XMM’s velocity, thus elongating its orbit and raising the perigee from 826 km to 7,365 km. One burn
was then made to fine tune the apogee to around 114,000km. The spacecraft, being tracked by ground stations in Perth, Kourou and Villafranca, is now
circling the Earth in this highly elliptical orbit once every 48 hours.

The XMM flight operations staff have found themselves controlling a spacecraft that responds exceptionally well. During these first orbits, the satellite
has been oriented several times with razor-sharp precision. On board systems have responded without incident to several thousand instructions sent by
controllers. “XMM is flying so beautifully” says Dietmar Heger, XMM Spacecraft Operations Manager. “The satellite is behaving better in
space than all our pre-launch simulations and we have been able to adjust our shifts to this more relaxed situation”.

On his return from French Guiana, Robert Lainé, XMM Project Manager immediately visited the Darmstadt Mission Control Centre, at ESOC. “The
perfect behaviour of XMM at this early stage reflects the constructive cooperation of European industrial companies and top
scientists. Spacecraft operations are in the hands of professionals who will endeavour to fulfill the expectations of the
astronomers and astrophysicists of the world. I am very happy that ESA could provide them with such a wonderful precision

During the early orbit phase, controllers have activated part of XMM’s science payload. The three EPIC X-ray cameras have been switched on and
vented. On 17 December the telescope doors were opened allowing the spacecraft’s golden X-ray Multi Mirror modules to see the sky. The Optical
Monitor telescope door was opened on 18 December. During this last weekend, XMM’s Radiation Monitor which records the flux of cosmic particles and
radiations was switched on.

Mission controllers have now placed XMM in a quiescent mode for the Christmas and New Year period. Full operations will resume on 4 January with
the start of the spacecraft commissioning phase due to last until 15 February. ESA’s XMM Science Operations Centre at Villafranca will be brought online
early January allowing the start of the exhaustive calibration and performance verification phase of XMM’s science instruments. Progress on this
calibration should allow the telescope to target and take “firstlight pictures” of its first X-ray sources next March.

For further information contact:

Robert Laine – XMM Project Manager

ESA – Estec (Noordwijk, The Netherlands)

Tel : +31 71 565 5621


ESA Public Relations Division

(Headquarters – Paris, France)

Tel: +33 (0)

Fax: +33 (0)

Further information on XMM and the ESA Science Programme can be found on the Worldwide Web at:

SpaceRef staff editor.