-June 25, 1998 Eileen Collins, the first U.S. woman commander of a Space Shuttle mission and her fellow astronauts for NASA s STS-93 mission toured the Operations Control Center (OCC) for the Advanced X-ray Astrophysics Facility (AXAF) today.

Cmdr. Ashby, Col. Collins

"We are honored to have this historic shuttle crew visit us and familiarize themselves with the OCC," said Harvey Tananbaum, director of the AXAF Science Center, which operates the OCC for the Smithsonian Astrophysical Observatory through a contract with NASA's Marshall Space Flight Center. "It is appropriate that a pathbreaking shuttle mission will deploy the premier X-ray observatory of this century."

AXAF is the third of NASA's Great Observatories along with the Hubble Space Telescope and the Compton Gamma Ray Observatory. It will observe in greater detail than ever before the hot, violent regions of the universe that cannot be seen with optical telescopes. Exploding stars, black holes and vast clouds of gas in galaxy clusters are among the fascinating objects that AXAF is designed to study. The satellite is currently in the final stages of testing at TRW Space and Electronics Group,the prime contractor, in Redondo Beach, California. In late August it will be flown aboard a specially-outfitted Air Force C-5 aircraft to Kennedy Space Center in Florida where it will be integrated with a Boeing booster and then installed in the Shuttle bay.

The shuttle crew that will take AXAF into space includes Collins (Col., USAF), Jeffrey Ashby (Cmdr., USN), pilot; Steven Hawley, Ph.D., mission specialist; Catherine Cady Coleman, Ph.D. (Major, USAF), mission specialist; and Michel Tognini (Col., French Air Force), mission specialist.

While visiting the OCC the crew learned how critical data (temperatures, voltages, etc.,) will be monitored while AXAF is in the bay of the shuttle. This information will be relayed to the shuttle from the OCC via Johnson Space Center. The condition of the satellite during launch and the first few orbits will determine if it can be sent on its way.

Unlike the Hubble Space telescope, AXAF will not be serviceable after it is in orbit. When the satellite has been released into space from the shuttle bay, a built in propulsion system will boost it into a large elliptical orbit around Earth. The nearest the observatory will come to Earth is 6,200 miles and its furthest point will be more than a third of the way to the moon. This means that the telescope will have approximately 52 hours of observing time each orbit.

AXAF images will show fifty times more detail than any previous X-ray telescope. The revolutionary telescope combines the ability to make sharp images while measuring precisely the energies of X-rays coming from cosmic sources. The impact AXAF will have on X-ray astronomy can be compared to the difference between a fuzzy black and white and a sharp color picture.