MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Mary Hardin
FOR IMMEDIATE RELEASEDecember 23, 1998
TOPEX/POSEIDON AUTONOMOUS NAVIGATION EXPERIMENT A SUCCESS
In an experiment that could change the way satellites are
flown in Earth orbit, the U.S./French TOPEX/Poseidon satellite
has successfully completed the first-ever NASA autonomous
navigational maneuver.
The experiment, which was designed to help validate
technology that allows Earth-orbiting satellites to autonomously
adjust their orbits, was conducted in early December from the
TOPEX/Poseidon mission control room at the Jet Propulsion
Laboratory.
"The importance of this maneuver lies in the fact that it
provides confidence that autonomous satellite actions can be
affordably developed and executed at an acceptable level of risk.
It is the first step in demonstrating a complete autonomous
navigation system for Earth-orbiting satellites," said Charles
Yamarone, program manager of JPL's Earth Science Flight Projects
Office.
In the experiment, flight controllers uplinked software to
TOPEX/Poseidon that autonomously planned the satellite's actions
and generated a series of commands to steer it. The software
required minimal input from ground controllers, consisting only
of changes in velocity and the time to execute the maneuver. The
software then computed the changes in satellite orientation and
the amount and timing of satellite thruster burns with no further
input from ground controllers.
TOPEX/Poseidon was selected for this experiment because it
is an operational satellite that needs to precisely maintain its
ground track. It also has an onboard computer that could be used
for the experiment without interrupting or jeopardizing satellite
normal operations. This computer is part of the experimental
Global Positioning System receiver that is normally used for
precision orbit determination.
NASA's first mission planned to test completely autonomous
navigation is the New Millenium Program's Earth Orbiter 1 planned
for launch in late 1999 or early 2000.
The TOPEX/Poseidon mission is managed by JPL for NASA's
Office of Earth Science, Washington, DC. JPL is a division of
the California Institute of Technology.
For more information, please visit the TOPEX/Poseidon web
site at http://topex-www.jpl.nasa.gov/
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12-23-98 MAH
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