XMM ready to leave ESTEC

XMM project and ESTEC Test Centre staff with XMM shortly before it was sealed in its transport container on 1 September 1999 for the journey to the Kourou launch site. XMM had earlier been hoisted from the Large European Acoustic Facility (LEAF, behind) onto the container base. ESA's X-ray Multi-Mirror (XMM) high-throughput X-ray spectroscopy mission was launched successfully by Ariane 504 on 10 December 1999. By virtue of its large collecting area and highly eccentric orbit, the 3.9-tonne XMM will make long observations of soft X-ray (100 eV to 12 keV) sources with unprecedented sensitivity. Most of the 50-200 sources in every image will be revealed for the first time. Whereas the German/US/UK Rosat mission, launched in 1990, pushed the number of known X-ray sources to 120 000, XMM will see millions. [Image Date: 01-09-99] [99.08.011-052]