RELEASE: 96-212

October 18, 1996


Donald Savage, Headquarters, Washington, DC (Phone: 202/358-1547)
Greg Shell, Marshall Space Flight Center, Huntsville, AL (Phone: 205/544-0034)

The world's most powerful X-ray observatory came a major step closer to completion recently with the assembly of its high resolution mirrors.

The last of four pairs of unique mirrors which form the heart of NASA's Advanced X-ray Astrophysics Facility (AXAF) were aligned and cemented into place at Eastman Kodak's Federal Systems Division in Rochester, NY, last month.

"The extreme sensitivity of the mirrors made the installation a very delicate and pain-staking process," said John Humphreys, Project Development Manager at NASA's Marshall Space Flight Center, Huntsville, AL. "Successful completion of the process represents a real achievement in the development of the telescope."

The high resolution mirror assembly is now being outfitted with additional hardware and a covering in preparation for testing and calibration in a special facility at Marshall, beginning in mid-November.

Unlike the concave, nearly flat mirrors used in optical telescopes, the AXAF mirrors are shallow, almost cylindrical cones. The four pairs of mirrors are nested inside each other. X-rays enter the telescope, graze off the mirrors -- much like a stone skipping across the surface of a pond -- and are focused onto a plane 30 feet behind the front of the mirrors.

The largest of the mirrors is 47.2 inches, which makes this mirror set the largest ever made. The size and accuracy of the mirrors will make AXAF 100 time more sensitive than previous X-ray telescopes, producing images 10 times sharper.

The observatory is scheduled for a Space Shuttle launch in 1998. In orbit, it will obtain never-before-seen images of highly energized X-ray sources -- such as neutron stars, black holes, debris from exploding stars, quasars, centers of galaxies and galaxy clusters.

AXAF will rank among NASA's great observatories, along with the Hubble Telescope and the Compton Gamma Ray Observatory. It will explore some of the most intriguing mysteries in space and offer a better understanding and knowledge of the universe.

Marshall manages development of the observatory for the Office of Space Science, NASA Headquarters, Washington, DC. TRW Space and Electronics Group, Redondo Beach, CA, is the prime contractor for the program. Ball Aerospace Division, Boulder, CO, provided hardware subsystems, and the AXAF mirrors were built and assembled by Hughes Danbury Optical Systems, Optical Coating Laboratory, Inc., Danbury, CT, and Eastman-Kodak Company, Rochester, N.Y.

EDITOR'S NOTE: An image to accompany this release is available to news media representatives by calling the Headquarters Imaging Branch at 202/358-1900. Photo numbers are:

     Color:            96-HC-680
     B&W:              96-H-680 (NASA HQ Public Affairs Office)