Mars Global Surveyor Mars Orbiter Camera (MOC)

MGS MOC Releases MOC2-321 to MOC2-324, 12 December 2002

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) “officially” began
its mapping mission on 9 March 1999, after MGS had spent about a year and a
half slowly changing its orbit to its final nearly-circular, nearly-polar
position approximately 380 km (236 mi) above the martian surface. When
mapping began, it was summer in the martian northern hemisphere, and winter
in the south. One of the primary objectives of MOC was to observe Mars for
one full Mars year, documenting changes in its weather and seasonal patterns
of polar cap growth and retreat. On 24 January 2001, MOC completed its first
Mars year–about 687 Earth days–as the planet returned to the exact same
time of year (in northern summer) that it had been at the start of mapping.

This week, MGS and MOC completed an unprecedented second Mars year of daily
global monitoring and detailed observations of the red planet. On 12
December 2002, Mars returned to the exact same position in its orbit around
the sun (or equivalently, the exact same time of the martian year) as it was
on 9 March 1999 and 24 January 2001. MGS has now entered its third Mars
year, and critical monitoring of weather patterns continues, along with
on-going efforts to gather high resolution images of future spacecraft
landing sites, provide detailed studies of geologic features, and observe
phenomena that change–like wind streaks–over time.

Current plans call for MGS and MOC to remain active through October 2004.
Between now and then, and in addition to its own scientific duties, the
spacecraft will play a small but extremely important role in supporting the
upcoming Mars Exploration Rover (MER) mission by providing a radio relay for
data being transmitted during the critical entry, descent and landing phase
of each of the rovers. Additionally, MGS may be used to augment science data
return. These functions will use the French-supplied Mars Relay and the
MOC’s computer buffer. A proposal is presently being prepared to further
extend the MGS mission to provide another full Mars year of weather
observations, to support landing site studies for NASA’s 2007 and 2009 Mars
missions, to scout locations for future detailed studies by the Mars
Reconnaissance Orbiter’s (MRO) advanced instrumentation, and to provide
critical observations supporting MRO’s 6-month long aerobraking period.

In the interim, MOC continues, every day, to acquire dazzling images of the
martian surface. As we now begin a third Mars year observing the planet from
the mapping orbit, we present (below) a sampling of recent images and
mosaics assembled by MOC scientists at Malin Space Science Systems.

Images Credit: NASA/JPL/MSSS

Caption by: K. S. Edgett and M. C. Malin, MSSS