ROSAT, the Roentgen Satellite, is an X-ray observatory developed through a cooperative program between Germany, the United States, and the United Kingdom. The satellite was designed and is operated by Germany, and was launched by the United States on June 1, 1990.

More information can be found at the ROSAT Science Data Center (http://hea-www.harvard.edu/rosat/rsdc_www/ros_welcome.html)

Courtesy NASA