Highest-Resolution View of "Face on Mars"
A key aspect of the Mars Global Surveyor (MGS) Extended Mission is the
opportunity to turn the spacecraft and point the Mars Orbiter Camera (MOC) at
specific features of interest. A chance to point the spacecraft comes about ten
times a week. Throughout the Primary Mission (March 1999 - January 2001), nearly
all MGS operations were conducted with the spacecraft pointing "nadir"---that is,
straight down. In this orientation, opportunities to hit a specific small feature of
interest were in some cases rare, and in other cases non-existent. In April 1998,
nearly a year before MGS reached its Primary Mission mapping orbit, several tests
of the spacecraft's ability to be pointed at specific features was conducted with
great success (e.g., Mars Pathfinder landing site, Viking 1 site, and Cydonia
landforms). When the Mars Polar Lander was lost in December 1999, this capability
was again employed to search for the missing lander. Following the lander search
activities, a plan to conduct similar off-nadir observations during the MGS Extended
Mission was put into place. The Extended Mission began February 1, 2001. On April
8, 2001, the first opportunity since April 1998 arose to turn the spacecraft and
point the MOC at the popular "Face on Mars" feature.
Viking orbiter images acquired in 1976 showed that one of thousands of buttes,
mesas, ridges, and knobs in the transition zone between the cratered uplands of
western Arabia Terra and the low, northern plains of Mars looked somewhat like a
human face. The feature was subsequently popularized as a potential "alien
artifact" in books, tabloids, radio talk shows, television, and even a major motion
picture. Given the popularity of this landform, a new high-resolution view was
targeted by pointing the spacecraft off-nadir on April 8, 2001. On that date at 20:54
UTC (8:54 p.m., Greenwich time zone), the MGS was rolled 24.8° to the left so that
it was looking at the "face" 165 km to the side from a distance of about 450 km.
The resulting image has a resolution of about 2 meters (6.6 feet) per pixel. If
present on Mars, objects the size of typical passenger jet airplanes would be
distinguishable in an image of this scale. An earlier picture obtained in June 2000
was combined with the new, April 2001 image, to produce a stereo ("3-D") view of
the western portion of the hill ("3-D" glasses with red for left eye and blue for right
eye are needed to view the anaglyph). The large "face" picture, above, covers an
area about 3.6 kilometers (2.2 miles) on a side; the
3-D picture is about 1 km (0.62
mi) wide. Sunlight illuminates the images from the left/lower left.
Images Credit: NASA/JPL/Malin Space Science Systems
|