ROSAT
Full Name: ROentgen SATellite
Phase: Past
Launch Date: June 01, 1990
Mission Project Home Page: http://heasarc.gsfc.nasa.gov/docs/rosat/rosat.html
ROSAT, the ROentgen SATellite, was an X-ray observatory developed through a cooperative program between the Germany, the United States, and the United Kingdom. The satellite was designed and operated by Germany, and was launched by the United States on June 1, 1990. The ROSAT mission began with a six-month, all-sky PSPC survey, after which the satellite began a series of pointed observations. It was turned off on February 12, 1999.
The ROSAT mission was divided into two phases: (1) After a two-month on-orbit calibration and verification period, an all-sky survey was performed for six months using the PSPC in the focus of XRT, and in two XUV bands using the WFC. The survey was carried out in the scan mode. (2) The second phase consists of the remainder of the mission and was devoted to pointed observations of selected astrophysical sources. In ROSAT's pointed phase, observing time was allocated to Guest Investigators from all three participating countries through peer review of submitted proposals. ROSAT had a design life of 18 months, but was expected to operate beyond its nominal lifetime.
On September 11, 1994, after four years of successful operation, the PSPC was shut down to conserve the remaining detector gas. This remaining gas was thought to have been used up during 1997 in a series of pointings to complete the all-sky survey coverage, but several other PSPC observations were carried out in 1998 and early 1999.