Donald L. Savage
Headquarters, Washington, D.C.                                    
           
August 24, 1994
(Phone:  202/358-1547)

Steve Roy
Marshall Space Flight Center, Huntsville, Ala.
(Phone:  205/544-0034)


RELEASE:  94-139

NASA Completes First Mirror FOR AXAF Observatory 

     The first and largest of eight mirrors for the Advanced
X-ray Astrophysics Facility (AXAF) has been successfully
completed, and is superior in quality to any X-ray mirror ever
destined for launch into space.  

     The mirror, designated P1, is the first of eight mirrors
which will be assembled into the AXAF telescope, a large
space-based observatory scheduled for launch in 1998.  The prime
contractor for the telescope is TRW, Redondo Beach, Calif.

     The P-1 mirror will form part of the high resolution mirror
assembly (HRMA), the central optical component in the AXAF
10-meter telescope.  At 48 inches in diameter, the completed
mirror will be the largest ever made to collect X-rays in space. 
The HRMA uses four pairs of precision-shaped mirrors to focus
X-rays from celestial sources onto the spacecraft's imaging
instruments.

     Built by Hughes Danbury Optical Systems (HDOS), Danbury,
Conn., the P1 mirror will be shipped to Eastman Kodak Company
(EKC), Rochester, N.Y., where it will initially be used in an
engineering test to verify telescope alignment processes.  The P1
mirror was X-ray tested in 1991 at NASA's Marshall Space Flight
Center, Huntsville, Ala.  It was returned to HDOS, trimmed to
final flight length, and then polished to remove distortion 
resulting from stress relief after trimming.

     The P1 mirror's imaging quality for high energy X-rays is
two times better than what was originally specified resulting in
a significant improvement in its scientific capability.


     Once in orbit, data from AXAF will be used to study X-ray
radiation and is expected to significantly improve scientific
understanding of some of the most energetic and violent processes
in the universe.  The observatory will produce "picture-like"
images and spectrograms which will yield information on
temperature and chemical composition of the objects it observes.

     AXAF is designed to work in concert with NASA's Great
Observatories already in orbit -- the Hubble Space Telescope
(HST) and the Compton Gamma-Ray Observatory.  Each observatory
makes observations of stars, galaxies, and other astronomical
objects in distinct and separate wavelengths of energy, including
visible light, ultraviolet, gamma rays, and, in the case of AXAF,
X-rays.  NASA launched the HST in 1990 and in 1991 launched the
TRW-built Compton Gamma Ray Observatory.

     The AXAF development team consists of NASA, the Smithsonian
Astrophysical Observatory, TRW, HDOS, EKC and Marshall Space
Flight Center, which manages the AXAF project for NASA's Office
of Space Science, Washington, D.C.

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