- Scientists have used an orbiting Mars craft to photograph
robotic landers that have been sitting dormant on the surface of the red
planet since their missions ended.
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- Using a newly developed trick, the researchers imaged
Mars Pathfinder, which in 1997 thrilled earthlings with its photographs
and the wandering science exploits of its Sojourner rover. Pathfinder appears
as a dark dot near a rock that scientists named Yogi during the mission.
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- The Viking 1 lander from 1976 is also visible, as a bright
dot in a separate image.
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- The photographs were made with NASA's Mars Global Surveyor
(MGS). Normally it can resolve features only down to about 3 feet (1 meter)
per pixel, not good enough to discern a typical landing craft from its
surroundings.
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- The new technique involves "pitching the spacecraft
at a rate faster than the spacecraft moves in its orbit around Mars,"
said scientists at Malin Space Science Systems, which operates the orbiter's
camera. The resolution of images -- across one dimension of the photograph
only -- is improved to about 20 inches (50 centimeters) per pixel.
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- The method, called image motion compensation, was developed
during 2003 with the goal of photographing the Mars Spirit rover, which
landed earlier this month, and its twin, Opportunity, slated to arrive
later in January.
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- Scientists plan to use radio data and on-site observations
from Spirit, and then couple that with the new imaging technique in coming
days in order to pinpoint its location and more intelligently pick science
targets for the rover to study.
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- The technique works only "when the location of the
lander is already fairly-well established," Malin scientists said.
They match known features -- such as the rock named Yogi near Pathfinder
-- with features spotted in the image to help pin down whether a dot is
the craft they're looking for.
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- The procedure
is unlikely to help in finding the European Space Agency's lost Beagle
2 lander or the similarly doomed Mars Polar Lander from 1999, the researchers
said.
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- "It would be extremely difficult to find a lander
for which the location is uncertain," Malin scientists said in a statement.
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