XMM-Newton
The X-ray Multi-mirror Mission (XMM-Newton) provides simultaneous non-dispersive spectroscopic X-ray imaging and timing, medium resolution dispersive X-ray spectroscopy and optical/UV imaging, spectroscopy and timing. In combination, the imaging cameras offer an effective area over the energy range from 150 eV to 12 keV of up to 2500 cm$^2$ at 1.5 keV and $\sim$1800 cm$^2$ at 5 keV. The gratings cover an energy range from 0.4 keV to 2.2 keV with a combined effective area of up to 120 cm$^2$ at 0.8 keV. XMM-Newton offers unique opportunities for a wide variety of sensitive X-ray observations accompanied by simultaneous optical/UV measurements. The majority of XMM-Newton's observing time is made available to the astronomical community by peer-reviewed Announcements of Opportunity. The scientific exploitation of XMM-Newton data is aided by an observatory-class X-ray facility which provides analysis software, pipeline processing, calibration and catalogue generation. Around 380 refereed papers based on XMM-Newton data are published each year with a high fraction of papers reporting transformative scientific results.