Röntgen Satellite. An X-ray satellite operated jointly by Germany, the United States, and the United Kingdom. Launched 1 June 1990, mission completed on 12 February 1999.

X-ray observatory developed as a collaboration between Germany, the United States, and the United Kingdom. It was launched by the United States on June 1, 1990. The mission ended after almost nine years, on February 12, 1999.

ROentgen SATellit, a Germany/UK/USA satellite dedicated to X-ray astronomy. It as launched June 1, 1990 on Delta II booster and remains in service as of 1998. It carries three instruments, one of which was used in a dedicated two-year survey of the entire celestial sphere. A second, the HRI (High-Resolution Imager), delivered the most detailed X-ray images of deep-sky sources to date.