PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

PHOTO CAPTION                                P-48593
                                             MGS Tilted Array
                                             April 30, 1997

This computer-generated view of Mars Global Surveyor shows the 
spacecraft's original aerobraking configuration (top), in which 
the left-hand solar panel is fully deployed and rotated so that 
its solar cell-side is facing away from the air flow that exerts 
drag force on the spacecraft during aerobraking.  The drawing 
below shows its newly modified aerobraking configuration, in 
which the same panel (on left) is now rotated 180 degrees so that 
the solar cell-side of the panel, shown by the blue surface, is 
now facing into the direction of the wind flow during 
aerobraking. The arrow indicates the location of the deployment 
mechanism, situated at the "shoulder" joint of the spacecraft, 
where a small damper arm was broken and wedged into a 2-inch 
space between the deployment hinge and the edge of the solar 
array.  The wedged damper arm prevented the panel from full 
deployment, so that the panel is tilted 20.5 degrees away from 
its fully deployed position seen above.

Mars Global Surveyor will be flown in this modified configuration 
during aerobraking, which begins one week after the spacecraft 
arrives at Mars on September 11, and lasts approximately four 
months.  Aerobraking will allow the spacecraft to slow its 
velocity by dipping repeatedly into the upper atmosphere of Mars 
during each closest approach to the planet, and to lower itself 
into the final mapping orbit for the beginning of science 
operations in March 1998.

Mars Global Surveyor is the first mission in a sustained program 
of robotic exploration of Mars, managed by the Jet Propulsion 
Laboratory for NASA's Office of Space Science, Washington, D.C.

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