A NASA X-ray astronomy satellite, one of the four Great Observatories, launched in 1999 July. It uses a mirror grazing-incidence telescope with a collecting area equivalent to that of a conventional 0.4-m optical telescope to observe X-rays of 0.1–10 keV (0.12–12 nm). Chandra provides sharper images (0″.5) and more detailed X-ray spectra than any previous X-ray mission. It is named after S. Chandrasekhar.

http://chandra.harvard.edu/ Official mission website.