XMM-Newton Observatory is a European Space Agency orbiting X-ray observatory launched in December 1999. XMM ((X-ray Multi-Mirror)-Newton is the most sensitive imaging X-ray observatory in the 250 eV–12 keV range ever flown, exceeding the mirror area and energy range of ROSAT, ASCA, and even the Chandra X-ray Observatory. It has three advanced X-ray telescopes, each containing 58 high-precision concentric mirrors nested to offer the largest possible collecting area. In addition, it carries five X-ray imaging cameras and spectrographs, and an optical monitoring telescope. The observatory moves in a highly elliptical orbit, traveling out to nearly one third of the distance to the Moon and enabling long, uninterrupted observations of faint X-ray sources.