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PHOTO CAPTION                              MRPS #83493
                                           August 25, 1997
                                           Syrtis Major on Mars
                                   
This image was acquired by the Mars Global Surveyor (MGS) Mars 
Orbiter Camera (MOC) on August 20, 1997, when MGS was 5.51 
million kilometers (3.42 million miles) and 22 days from 
encounter. At this distance, the MOC's resolution is about 20.6 
km per picture element, and the 6800 km (4200 mile) diameter 
planet is about 330 pixels across. North is at the top of the 
image. The MGS spacecraft pointed the camera at the center of the 
planet (near the dark, morning sunrise line, or terminator) at 
23.6¡ N, 307.3¡ W. The irregularity of the terminator seen in 
this image results from contrast processing. This image shows the 
prominent dark feature Syrtis Major, believed to be a relatively 
dust- free area of bedrock outcrop and sand dunes. The large 
Hellas impact basin (2000 km or 1250 miles across) is seen at the 
bottom of the picture. Clouds from the south polar region fill 
the basin. The north polar residual ice cap, surrounded by a dark 
annulus of sand, is seen at the top of the picture. 

Launched on November 7, 1996, Mars Global Surveyor will enter 
Mars orbit on Thursday, September 11 around 6:30 PM PDT. After 
Mars Orbit Insertion, the spacecraft will use atmospheric drag to 
reduce the size of its orbit, achieving a circular orbit only 400 
km (248 mi) above the surface in March 1998, when mapping 
operations will begin. At that time, MOC narrow angle images will 
be 14,000 times higher resolution than this picture, and global 
wide angle images will be 3 times better. 

The Mars Global Surveyor mission is operated by the Mars Surveyor 
Operations Project managed for NASA by the Jet Propulsion 
Laboratory, Pasadena CA. JPL is a division of the California 
Institute of Technology (Caltech). The Mars Orbiter Camera is a 
duplicate of one of the six instruments originally developed for 
the Mars Observer mission. It was built and is operated under 
contract to JPL by an industry/university team led by Malin Space 
Science Systems, San Diego, CA.  The Jet Propulsion Laboratory 
operates the Mars Global Surveyor spacecraft with its industrial 
partner, Lockheed Martin Astronautics, from facilities in 
Pasadena, CA and Denver, CO.

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