Press Release

Europe’s latest space telescope is off to a good start

By SpaceRef Editor
December 10, 1999
Filed under

Nr. 53-99 – Paris

Europe’s latest space telescope is off to a good start

The world’s most powerful observatory for X-ray astronomy, the European Space Agency’s XMM satellite, set off into space from Kourou,
French Guiana, at 15:32 Paris time on 10 December. The mighty Ariane 5 launcher, making its very first commercial launch, hurled the 3.9-tonne
spacecraft into a far-ranging orbit. Within one hour of lift-off the European Space Operations Centre at Darmstadt, Germany, confirmed XMM was
under control with electrical power available from the solar arrays.

“XMM is the biggest and most innovative scientific spacecraft developed by ESA so far,” said Roger Bonnet, ESA’s Director of Science. “The
world’s space agencies now want the new technology that ESA and Europe’s industries have put into XMM’s amazingly sensitive X-ray
telescopes. And the world’s astronomers are queuing up to use XMM to explore the hottest places in the universe. We must ask them to be patient
while we get XMM fully commissioned.”

XMM’s initial orbit carries it far into space, to 114,000 kilometres from the Earth at its most distant point. On its return the satellite’s closest
approach, or perigee, will be at 850 kilometres.

The next phase of the operation, expected to take about a week, will raise that perigee to 7000 kilometres by repeated firing of XMM’s own
thrusters. The spacecraft will then be on its intended path, spending 40 hours out of every 48-hour orbit clear of the radiation belts which spoil the
view of the X-ray universe. Technical commissioning and verification of the performance of the telescopes and scientific instruments will then
follow. XMM should be fully operational for astronomy in the spring of 2000.

All of ESA’s science missions present fresh technological challenges to Europe’s aerospace industries. In building XMM, the prime contractor
Dornier Satellitensysteme in Friedrichshafen in Germany (part of DaimlerChrysler Aerospace) has led an industrial consortium involving 46
companies from 14 European countries and one in the United States.

XMM stands for X-ray Multi-Mirror Mission. Its main telescopes will gather X-rays from the cosmos with 120 square metres of gold-coated
surfaces, in 174 mirrors fashioned, smoothed and nested together with high precision by contractors in Germany and Italy.

With XMM, Europe has taken the lead in X-ray missions and X-ray detectors: the most sensitive and largest ever made. The four complex scientific
instruments on XMM have been developed and led by European scientists with participation from institutes worldwide.

Compared with NASA’s Chandra X-ray telescope launched earlier this year, XMM is at least 5 times more sensitive. The gain in sensitivity is
15-fold, at high X-ray energies. But Chandra has a sharper view, so the two missions are complementary and there is close transatlantic
collaboration among the scientists involved.

Prime scientific objectives for XMM are to find out exactly what goes on in the vicinity of black holes, and to help to clear up the mystery of the
stupendous explosions called gamma-ray bursts. Other hot topics for investigation include cannibalism among the stars, the release of newly made
chemical elements from stellar explosions, and the origin of the cosmic rays that rain on the Earth.

XMM is one of a carefully-planned series of scientific satellites built in Europe by which ESA has established a pioneering role in space astronomy.
Recently completed missions include the very successful star-mapping satellite Hipparcos, and the Infrared Space Observatory which revolutionized
astronomers’ knowledge of the cool parts of the universe.

Coming along after XMM are Integral for gamma-ray astronomy, FIRST for the far-infrared, and Planck for examining the entire cosmic
microwave background far more accurately than ever before.

For further information contact:

ESA Public Relations Division

Tel: +33 (0)1.53.69.71.55

Fax: +33 (0)1.53.69.76.90

For updates on the XMM launch, and background on the mission see:

http://sci.esa.int/xmm/

SpaceRef staff editor.