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
Mars Global Surveyor Mission Status
April 21, 1999
Flight controllers for NASA's Mars Global Surveyor mission
are continuing to work toward isolating what caused a hinge on
the spacecraft's high-gain telecommunications antenna to stop
moving last week.
This afternoon, engineers received the results of a test
they conducted earlier in the day that moved the hinge one-half
of a degree from side to side. The information from the
spacecraft shows that the hinge moves freely in one direction,
but it's motion appears to be obstructed in the opposite
direction. The tests are designed to help engineers determine if
the obstruction is internal to the motor mechanism, or external,
such as a thermal blanket or cable obstruction. Flight
controllers continue to analyze the test results and will send
additional commands to the spacecraft tomorrow that will attempt
to move the hinge a little bit more -- one full degree -- in each
direction.
The spacecraft remains in good health and the science
instruments are turned off while engineers continue to define the
hinge.
There are two hinges at the end of the boom that connect to
the high-gain antenna. One hinge, called the azimuth hinge, moves
the antenna from side to side; the other hinge, called the
elevation hinge, moves the antenna up and down. The azimuth
hinge stopped moving midway between its "parked" position and the
position its in when it is transmitting data to Earth.
Mars Global Surveyor is managed by JPL for NASA's Office of
Space Science, Washington, DC. JPL's industrial partner is
Lockheed Martin Astronautics, Denver, CO, which developed and
operates the spacecraft. JPL is a division of the California
Institute of Technology.
Further information about the mission is on the Internet at:
http://mars.jpl.nasa.gov/mgs/
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