Michael J. Braukus Headquarters, Washington, D.C. February 11, 1991 (Phone: 202/453-1549) John J. Loughlin II Goddard Space Flight Center, Greenbelt, Md. (Phone: 301/286-5565) RELEASE: 91-23 GERMAN SATELLITE TO BEGIN U.S. SCIENCE MISSION The German Roentgen Satellite (ROSAT) entered a new phase of science operation on Feb. 8, 1991 as it began the pointed observations of what NASA project officials have called particularly interesting sources of X-ray emissions. Scientists are interested in X-ray images because they specifically highlight regions in all celestial systems where high energy phenomena occur. Particularly rich sources of X-ray emissions are supernova remnants, galaxy clusters, quasars binary star systems containing neutron stars or black holes. The start of the pointed observations phase signals the beginning of the U.S. ROSAT guest observer program. The U.S. ROSAT Science Data Center (USRSDC) will support guest investigators through the processing and distribution of the ROSAT pointed data and by providing facilities for the scientific analysis of the data. NASA's Goddard Space Flight Center, Greenbelt, Md., is the site of the USRSDC, a collaborative project between the Goddard Laboratory for High Energy Astrophysics, the Smithsonian Astrophysical Observatory High Energy Astrophysics Division and the Goddard Space Data and Computing Division. - more - - 2 - During the satellite's first 6 months of full time operation, an all-sky survey of the cosmos was conducted by German scientists using ROSAT's German Position-Sensitive Gas Proportional Counter (PSPC). This survey resulted in the most sensitive, complete map of the X-ray sky to date and gave scientists more than 50,000 sources from which to choose as targets for the pointed phase. The joint international team responsible for ROSAT -- scientists from the United States, the Federal Republic of Germany and the United Kingdom -- will divide observation time using the PSPC and the NASA-supplied High Resolution Imager (HRI) at the focal plane of the German-made ROSAT telescope. The team reports that ROSAT's scientific instruments are operating better than expected, and the image quality from the X-ray mirror is as good or better than previously indicated by ground testing. There have been problems with the spacecraft which have affected some of its built-in redundant capabilities. While these problems are still being analyzed, they are not expected to impact the science mission. The spacecraft is currently in a circular orbit at an altitude of about 358 miles, at an inclination of 53 degrees. It was launched on June 1, 1990 from Cape Canaveral Air Force Station, Fla., on a Delta expendable launch vehicle. Within NASA, the ROSAT program is managed by the Goddard Space Flight Center for the Office of Space Science and Applications. - end - TO: MDS/PRA Group 1615 L Street, N.W. - Suite 100 Washington, D.C. 20036 DATE & TIME: 2/12/91 ORDERED BY: THERESA HOUSER NASA Headquarters/PM 400 Maryland Avenue, SW Washington, DC 20546 PHONE: 202/453-8400 PROJECT TITLE: Release No: 91-023 PRINT ORDER: 2378 PRINTING: Camera Ready, lst pg on NASA logo, other pages plain ENCLOSE & MAIL: Release of pages MAIL DATE: 2/13/91 EXTRA COPIES: Deliver specified quanities to locations below: 50 copies 275 copies 75 copies -------------------- ------------------- ----------------- National Press Club NASA Mailroom NASA Newsroom 13th floor newsrack NASA Headquarters NASA Headquarters National Press Building 600 Independ. Ave, SW 400 Maryland Ave, SW 529 14th Street, NW Room A16 Room 6043 Washington, DC 20045 Washington, DC 20546 Washington, DC 20546 MEDIA SUMMARY OPTION: Name-by-name media summary - 1 copy CLIENT COMPUTER LISTS: Run the following: LS-CA, LS-FA, LS-GA*27E LS-KA, TYPE OF RELEASE & PIX: General news X 21:T-23:T PUT ADDRESSING ON: Self-mailer MEDIA SELECTION: END OF ORDER FORM END OF TRANSMISSION