This is the full-resolution, rotated perspective image of Nirgal Vallis,
a subset of PIA00942. Nigral Vallis is one of a number of canyons
called valley networks or runoff channels. Much of the debate
concerning the origin of these valleys centers on whether they
were formed by water flowing across the surface, or by collapse and
upslope erosion associated with groundwater processes. At the
resolution of this image, it is just barely possible to discern an
interwoven pattern of lines on the highland surrounding the valley,
but it is not possible to tell whether this is a pattern of surficial debris
(sand or dust), as might be expected with the amount of crater
burial seen, or a pattern of drainage channels. With 4X better
resolution from its mapping orbit, MOC should easily be able to
tell the difference between these two possibilities.
Launched on November 7, 1996, Mars Global Surveyor entered Mars
orbit on Thursday, September 11, 1997. The spacecraft has been
using atmospheric drag to reduce the size of its orbit for the past
three weeks, and will achieve a circular orbit only 400 km (248 mi)
above the surface early next year. Mapping operations begin in
March 1998. At that time, MOC narrow angle images will be 5-10 times
higher resolution 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's Mars Surveyor Operations Project
operates the Mars Global Surveyor spacecraft with its industrial
partner, Lockheed Martin Astronautics, from facilities in Pasadena,
CA and Denver, CO.
Photo Credit: NASA/JPL/Malin Space Science Systems
MRPS #84704 100197_8 605.obl.sub.str/MOC212E 559303731.605 P006_05
Full Res Image