An ESA satellite for X-ray astronomy, launched in 1999 December, named from its X-ray multi-mirror design and to honour Isaac Newton. It carries three grazing-incidence telescopes with CCD detectors for imaging and spectroscopy in the energy range 0.1–12 keV (120–1 nm), plus a 0.3-m telescope that checks for visual variability. XMM-Newton is in a highly elliptical 48-hour orbit to allow extended observations of sources.
http://xmm-newton.esa.int/ ESA mission website.
Subjects: Astronomy and Astrophysics.