X-rays are emitted by the hottest known sources such as stars, hot interstellar gases, black holes, galaxies and galaxy clusters. The cameras on the XMM-Newton satellite (for X-ray Multi-Mirror) are the most sensitive yet built to detect them and its mirrors are among the most powerful ever developed for X-rays.

XMM-Newton was launched on 10 December 1999 from Kourou by an Ariane 5 vehicle. It is still operating today, circling Earth in a 48-hour, 40°-inclined elliptical orbit at a distance of 114,000 km at its furthest point and 7,000 km at its closest.

XMM-Newton is the 2^nd cornerstone mission of the European Space Agency’s Horizon 2000 programme. With support from CNES, research laboratories at the CEA (Commissariat à l’énergie atomique et aux énergies alternatives) and the IAS (Institut d'Astrophysique spatiale) contributed to the satellite’s EPIC instrument, while IRAP (Institut de Recherche en Astrophysique et Planétologie) developed its ERMS instrument. The Strasbourg Observatory, the CEA’s Saclay facility and IRAP are also playing an active role in the XMM-Newton Survey Science Centre (SSC) that conducts systematic analysis of observations. Some 2,000 astronomers around the world use XMM-Newton data.