Large space observatories

The evolution and prospects for wide-ranging multi-spectral astronomy from space are examined. Since all objects - with the single exception of black holes - emit radiation and there are only a few relatively narrow 'windows' where particular wavelengths of this radiation penetrate the earth's atmosphere to be studied at ground level, we must resort to placing the great observatories of the new era of astronomy into space to further explore the universe. NASA has developed a program of space astronomy intended to permit eventual simultaneous observations across nearly the entire electromagnetic spectrum. Four major space observatories are described that are at various stages of planning and development. The Hubble space telescope was scheduled to be launched from the Space Shuttle in August 1986 to study the universe at wavelengths from the near infrared to the far ultraviolet (about 1100 to 11,000 angstroms); the five scientific instruments to be used are discussed in detail. The gamma ray observatory is scheduled for a 1988 launch. SIRTF (the space infrared telescope facility) is under development and scheduled to go aloft about 1983. AXAF (the advanced X-ray astrophysics facility) is in the phase B concept definition stage, with launch planned for the mid-1990s. Diagrams are included.