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6/23/88:  NASA SATELLITE TECHNOLOGY AIDS FUTURE SPACE RESEARCH MISSIONS

June 23, 1988

RELEASE:  88-84


     NASA's Seasat satellite, launched 10 years ago this week,
ushered in a new era of space research focusing on unsolved
questions of the world's oceans and weather.

     Launched on June 26, 1978, on an Atlas-Agena rocket from
Vandenberg Air Force Base, Calif., Seasat carried a payload of
five scientific instruments unlike any package on previous
remote-sensing satellites.

     Seasat tested a payload of advanced sensing instruments and
during its 3-1/2-month mission collected oceanographic
information comparable to a century's worth of observations from
a fleet of ships.

     Among the experimental instruments Seasat pioneered were a
synthetic aperture radar, which provided highly detailed images
of ocean and land surfaces; a radar scatterometer to measure
near-surface wind speed and direction; a radar altimeter to
measure the height of the ocean surface and waves; and a scanning
multi-channel microwave radiometer to measure surface
temperature, wind speeds and sea ice cover. The satellite also
carried a passive visual and infrared radiometer to provide
supporting data for the other four experiments.

     Seasat demonstrated how space sensors could be used in
oceanography -- becoming a baseline for a new generation of
international missions planned that could provide answers to some
of the world's most baffling and threatening weather phenomena.

     Examples include an unusual water warming in the eastern
Pacific Ocean in 1982 and 1983.  Called El Nino, this phenomena
caused billions of dollars in damage and considerable loss of
life.  Scientists also are investigating an increase of carbon
dioxide in the atmosphere, which could have severe consequences
on plants and animal life.  Missions derived from Seasat are
expected to help scientists understand both phenomena.

     These new generation of oceanographic missions are expected
to provide important, cost-saving aids for such industries as
fishing, shipping and offshore oil production; the National
Oceanic and Atmospheric Administration; and the U.S. Navy.

     TOPEX/Poseidon and the NASA Scatterometer (NSCAT) are two
oceanographic missions scheduled.

     TOPEX/Poseidon, a joint satellite mission with the French
space agency (CNES), is scheduled for a late 1991 launch on an
Ariane rocket. It will map the circulation of the world's oceans
using a radar altimeter.

     NSCAT is a second-generation instrument being developed to
measure wind speed and direction over the oceans' surfaces. A
proposal to fly NSCAT as part of the payload on Japan's planned
Advanced Earth Observation Satellite is currently under
review.

     Both TOPEX/Poseidon and NSCAT are intended to support
oceanographic studies during the 1990s under the World Ocean
Circulation Experiment and the Tropical Oceans Global Atmospheres
Experiment. These programs, sponsored by the World Climate
Research Program and scheduled to continue operations for a
decade, involve studies at and below the ocean surface in all
parts of the world's seas.

     Other international projects scheduled include the European
Space Agency's first remote-sensing satellite, Earth Resources
Satellite 1 due for launch in 1990; Japan's Earth Resources
Satellite 1 scheduled for a 1992 launch; and Radarsat, a proposed
1994 mission that would be a cooperative venture between Canada
and the United States.

     Seasat's technology has not been limited to satellite
oceanography.

     The Shuttle Imaging Radar (SIR), a series of synthetic
aperture radar experiments flown on the Shuttle was a direct
follow-on of Seasat's synthetic aperture radar.  This marked the
first time NASA had flown that advanced radar instrument in
space.

     The first and second experiments in the series, SIR-A, which
flew on a shuttle mission in 1981, and SIR-B, a shuttle payload
in 1984, offered scientists several unexpected discoveries. SIR-A
pierced cloud-covered rain forests of Guatemala to reveal
previously unknown agricultural canals dug by the ancient Maya.
SIR-B penetrated the sands of Egypt to produce a picture of a
riverbed buried for many centuries.

     NASA's Jet Proplusion Laboratory (JPL), Pasadena, Calif. is
currently working on SIR-C slated for a 1991 shuttle mission.  It
will be combined with a German/Italian X-band radar.  Also
planned is an advanced radar system that will be flown on an
Earth Observing System platform as part of NASA's Space Station
program in the late 1990s.

     A radar similar to the first flown on Seasat is scheduled on
NASA's Magellan mission to Venus in April 1989. Magellan will use
a synthetic aperture radar to pierce Venus' dense cloud cover to
provide the most complete, highest-resolution images of the
planet's surface ever made.

     Another planetary mission benefiting from Seasat is the Mars
Observer, scheduled for launch in 1992. That spacecraft will
orbit the red planet to conduct extensive studies of the Martian
surface with instruments including an altimeter derived from
Seasat.

     Seasat was funded by NASA's Office of Space Science and
Applications, Washington, D.C.  Gene Giberson was JPL Seasat
project manager; James A. Dunne was project scientist. S.W.
McCandless, Jr. was Seasat program manager at NASA Headquarters,
Washington, D.C.

     An international symposium celebrating Seasat's launch
anniversary will be hosted in London next Tuesday through
Thursday (June 28-30) by the British National Space Centre. Gene
Giberson, JPL's project manager for Seasat, and Peter Woiceshyn,
a JPL scientist who has worked on Seasat continuously since its
inception, will be featured speakers.

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                                                       Eric