Contact: Alice Galloway
Corporate Communications
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For Immediate Release

SRI International Will Operate Radio Telescope To Test Mars Global Surveyor
Spacecraft Signals

A Team from SRI, Stanford University, NASA and JPL Will Send and Receive
Signals from 150-Foot Parabolic Reflector Antenna Located in the Stanford

MENLO PARK, Calif. (November 22, 1996) -- On early Sunday, Monday and
Tuesday mornings of next week (November 24, 25 and 26), SRI International
will operate a radio telescope and its 150-foot parabolic reflector antenna
(called the "dish") to test UHF communication signals to and from the Mars
Global Surveyor spacecraft that was launched on November 7. The tests will
be conducted in collaboration with the Stanford University School of
Engineering STAR Lab, the Jet Propulsion Laboratory (JPL) and NASA
spacecraft experimenters.

The team will listen for signals from the Mars orbiter part of the
spacecraft and will send signals to simulate the operation of the Mars
lander apparatus so that the UHF communication link to be employed at Mars
can be checked out before the spacecraft leaves Earth's vicinity. It will be
impossible to receive these signals from Earth when the spacecraft is near
Mars because of the great distance.

Stanford University personnel will analyze and interpret the received
signals, which will be reported on a World Wide Web page in real time
( JPL representatives will access
data directly from the spacecraft via a network connection through JPL, and
other personnel will control the data transmissions sent from the dish. SRI
will provide the tracking and transmitter operations.

"We are very excited about the experiments to be conducted next week," said
Michael D. Cousins, Program Manager with SRI's Geoscience and Engineering
Center. "The program is an excellent opportunity for exercising our
capabilities for high sensitivity radio signal acquisition and an occasion
to newly apply our UHF transmitter in a unique and useful way."

The dish, which weighs 300,000 pounds and is located in the hills behind
Stanford University near Interstate 280, concentrates radio signals from
space and focuses them on an antenna. The radio signals are then converted
by the antenna into electric signals, which are in turn strengthened by a
receiver and recorded by computer.

The dish was constructed for the U.S. Department of Defense in the early
1960s and has been used since then for radio propagation and phenomenology
research. It was used for about ten years in conjunction with the Pioneer
spacecraft program to study solar wind plasma and has also been used for
radioastronomy applications, diagnosis of signals from disabled spacecraft,
transmission to spacecraft and spacecraft telemetry reception. The dish,
which was renovated recently, has been used for radioastronomy research and
training. SRI also uses the dish to instruct and inspire local high school
students through a volunteer program.

SRI International, celebrating its fiftieth anniversary this year, is one of
the largest research, technology development and consulting firms in the
world. SRI's Geoscience and Engineering Center specializes in the analysis of
earth and space environments and their affects on people and systems.

SRI International Web address: