[sci.space] Astronomy Technique

markf@scicom.AlphaCDC.COM (Mark Felton) (10/26/86)

NASA NEWS -> Oct 3, 1986

NEW SPACE ASTRONOMY TECHNIQUE DEVELOPED TO STUDY CELESTIAL BODIES

	A new space radio-astronomy technique, using an orbiting satellite
to study celestial objects, has been successfully tested by scientists at
NASA's Jet Propulsion Laboratory, Pasadena, California.
	An international team of scientists conducted experiments during
July and August employing a new space technique called very long baseline
interferometry (VLBI). They combined data from radio telescopes on the ground
with data from an antenna on NASA's Tracking and Data Relay Satellite System
(TDRSS) spacecraft, managed by NASA's Goddard Space Flight Center, Greenbelt,
Md.
	Investigators obtained better resolution of three quasars than is 
possible in ground based radio studies at the same wavelength. Quasars, or
quasi-stellar objects, are among the most distant objects known. The 
resolution obtained from the orbiting VLBI experiment was equivallent to that
of a radio telescope with size of 1.4 Earth diameters. The quasars studied
are designated 1730-130, 1741-038 and 1510-089.
	For the first time, a VLBI experiment used an orbiting satellite as
one of its radio telescopes. Previously, scientists linked widely separated
antennae on the ground with VLBI techniques to produce high-resolution radio
astronomy studies of celestial objects.
	Primary ground observatories in the experiment were NASA's Deep
Space Network 210-foot antenna in Australia and the Institute of Space and
Astronautical Sciences' 64 meter antenna at Usuda, Japan. An 80 foot 
antenna at the Radio Research Laboratory in Kashima, Japan, also was used
to check performance of the larger ground antenna.

	Researchers believe the experiment's success demonstrates the 
feasibility of a proposed orbiting VLBI mission. That mission would use
a satellite dedicated to radio-astronomy observations and would yield new
data on many celestial phenomena, including the nature of galactic nuclei,
the overall phenomena, including the nature of galactic nuclei, the overall
distance scale of the Universe and the formation of new stars.
	The research team led by Gerald S. Levy and other JPL scientists
included investigators from M.I.T.; the Haystack Observatory, Westford,
Mass.; Bendix Field Engineering Corp., Columbia, Md.; the Spacecom/TRW/
Bendix team White Sands, N.M. and NASA's Goddard Space Flight Center, 
Greenbelt, Md.
	Australian participants were from the Commonwealth Scientific
and Industrial Research Organization and Australian National University's
Mount Stromlo Observatory. Japanese experimenters were from the Institute
of Space and Astronautical Science, the Nobeyama Radio Observatory and the
Radio Research OLaboratory. 
	NASA's portion of the VLBI experiment was jointly sponsored by the
Office of Space Tracking and Data Systems and Office of Space Science and
Applications.
------------------------------------------------------------------------
NASA News Release 86-140
Leon Perry Headquarters, Washington, D.C and
Franklin O'Donnell Jet Propulsion Laboratory, Pasadena, Calif.
Reprinted with permission for electronic distribution