XMM-Newton, the most powerful X-ray observatory ever built and launched into space, marks its 10th anniversary on December 10th. XMM-Newton's observations have revolutionised the way we view the hottest and most extreme regions of the Universe.

Scientists from the UK who have played a pivotal role in the success of the orbiting observatory, which is the size of a small bus, will be marking the occasion at a special event in Madrid organised by the European Space Agency (ESA).

"After 10 years of operation and over 600 million kilometres on the clock, XMM-Newton is continuing to perform outstandingly well," says Dr Steve Sembay, from the University of Leicester who is Principal Investigator of one of the instruments on board.

Ten achievements of XMM-Newton:

+ made crucial observations that have impacted on every aspect of astronomy

+ traced the largest structures in space: the galaxy clusters

+ probed the regions closest to stellar-sized black holes in our Galaxy, and the super-massive black holes at the heart of external galaxies

+ showed how super-massive black holes grow over time and drive the evolution of the most massive galaxies in the universe

+ tracked the production and dispersal of the chemical elements by exploding stars

+ measured powerful magnetic activity in young stars like our Sun

+ discovered that Mars has a vastly larger atmosphere than previously thought

+ played a key role in the study of the elusive "dark matter", believed to account for the missing mass of the Universe

+ observed X-rays emitted from around the Earth and around other planets such as Saturn and Jupiter

+ made the largest catalogues of cosmic X-ray emitters ever - over a quarter of a million entries in the latest release - providing vast samples of newly discovered objects

The European Space Agency's mission has three gold-coated mirror modules which focus X-rays onto advanced instruments on board.

The development and construction of two of the three science instruments was led by UK groups, including teams at the University of Leicester and the Mullard Space Science Laboratory of University College London; the latter also contributed to the third instrument on board. Other UK institutions that have been involved include the University of Birmingham and the University of Cambridge.

The international instrument teams play a vital role in maintaining the instruments in orbit and ensuring they continue to deliver good science.

The UK is also home to the Leicester-led XMM-Newton Survey Science Centre (SSC), an international consortium which plays a complementary role in the XMM-Newton project, carrying out the science data processing for every observation and using the XMM-Newton observations to compile the largest catalogues of cosmic X-ray sources ever made.

Professor Mike Watson, from the University of Leicester's Department of Physics and Astronomy and XMM-Newton's Survey Scientist said: "XMM-Newton has allowed astronomers to peer deeper than ever before into the cosmos at X-ray wavelengths, giving us new insights into some of the most extreme regions of the Universe."

"It is still one of the foremost space observatories in operation, and one of the most successful space missions, yielding over 2000 scientific publications to date. The instruments are still in very good condition and the discoveries and cutting-edge science continue to accumulate.

"Next year the University of Leicester celebrates the 50th anniversary of its involvement in space science. The success of XMM-Newton is a testament to the far-reaching implications of this research."