Paula Cleggett-Haleim                                                                                       
May 20, 1991
Headquarters, Washington, D.C.
(Phone:  202/453-1547)

RELEASE:  91-76

ASTRO MISSION TO REFLY

  NASA today announced that the second Astro mission will fly 
aboard the Space Shuttle.  "We are delighted to be able to 
refly this proven scientific performer," said Dr. Lennard A. 
Fisk, Associate Administrator for Space Science and 
Applications.

  The success of the earlier mission and the demonstrated 
ability of the instruments to acquire high-quality scientific 
data are among the major reasons for reflight of the Astro 
payload.  

  Astro-2, like Astro-1 which flew in December of 1990 aboard 
Space Shuttle Columbia, will be dedicated to a single 
scientific discipline - astrophysics.  The following three 
instruments will fly on Astro-2 and observe energetic objects 
in space in the ultraviolet portion of the electromagnetic 
spectrum:

  o                                            The Hopkins 
Ultraviolet Telescope  (HUT), developed at Johns  
Hopkins University, performs spectroscopy, breaking light  
  into its constituent colors, allowing scientists to analyze 
the 
  chemical composition and temperature of the objects HUT  
observes. 

  o                                            The Ultraviolet 
Imaging Telescope (UIT), developed by NASA's
                                               Goddard Space 
Flight Center, produces images of especially   hot components 
of                                             nebulae, stars 
and galaxies. These images 
  help to explain the physical structure of such objects.

  o  The Wisconsin Ultraviolet Photopolarimeter Experiment  
  (WUPPE), developed at the University of Wisconsin, measures 
  a subtle characteristic of light, its polarization.  These  
measurements 
  probe the orientation and detailed physics of the distant  

  regions in which the light originates.  

                            -more-

                             -2-

  Astro-2 complements the much larger Hubble Space Telescope.  
HUT, for example, explores a region of the spectrum 
immediately adjacent to that studied by Hubble.  UIT, because 
of its very large field of view, can serve as a "finder" for 
the powerful imaging devices aboard Hubble.  Finally, WUPPE's 
precision polarimetry adds another dimension to the physical 
understanding of astronomical objects obtained from Hubble's 
collection of instruments.

  During the Astro-1 mission, new results were obtained at 
wavelengths observable only from space.  Astronomers gained 
insights into the properties of diffuse dust found between 
stars as well as details of the formation of new stars in 
distant galaxies.  They also learned that the predicted decay 
of certain sub-atomic interstellar particles did not occur, at 
least not at the expected level.

  Dr. David Huenemoerder, Program Scientist on Astro-1, said, 
"The Astro Principal Investigators and their teams will be 
very pleased.  That first flight was just a taste of the 
scientific insights they expect to emerge from Astro-2."

  Astro-2 will be managed by the Marshall Space Flight Center, 
Huntsville, Ala., for the Office of Space Science and 
Applications, NASA Headquarters, Washington, D.C. 

                            -end-