Mars Global Surveyor
Mars Orbiter Camera

Mars Approach Images - 19-21 August 1997

Eight images of Mars were acquired during a 46 hour period between 4:40 AM August 19, 1997 and 2:50 AM August 21 1997. The images are shown above as a sequence that increases in longitude. In practice, the images were acquired in two sets of four pictures each. Within each set, the images were separated by a little of 6 hours, while the time step between the two sequences (that is, between Image 4 and Image 5) was a little of 9 hours. This permitted spacing by about 45° between the final eight images. The sequence as shown above is 1-5-2-6 on the first row and 3-7-4-8 on the second row. The central latitude of all eight images is the same (23.6°N). The central longitude of each of these images is:

1 - 172.4°W   5 - 217.4°W   2 - 262.3°W   6 - 307.4°W
3 - 352.2°W   7 -  72.2°W   4 -  82.1°W   8 - 127.2°W
Careful examination of the images above shows that the planet changes size from frame to frame. During the roughly two days over which these images were acquired, the distance to Mars reduced by 470,000 km, or about 8%. Thus, Image 8 is 8% larger than Image 1.

MPEG/Quicktime Movie of Planet Rotating

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 these pictures, and global wide angle images will be 3 times better than these pictures.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in 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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