November 27, 2007
Mars Rover Spirit Seen in Image By HiRISE Camera
Spirit, the dusty Mars rover twin with the bad leg, shows up in a photo taken by the University of Arizona's orbiting HiRISE camera as the rover heads for a safe winter refuge.
The long-lived rovers got a fifth extension of their mission last month, one that could extend their operations into 2009. Launched in 2003, they landed on Mars in January 2004 and were expected to function for 90 days.
But a massive Martian dust storm earlier this year clouded up Spirit's solar panels, threatening its ability to store the power needed to keep its electronics guts from freezing during the long, cold mostly dark winter and continue its work.
To get the most power possible out of the solar panels, scientists wanted to park Spirit for the winter at a precise, and fairly steep angle, said rover science team member Ken Herkenhoff of the U.S. Geological Survey in Flagstaff.
"We need that 25-degree tilt to survive the winter," said Herkenhoff. "We did that last winter, but because of the dust storm Spirit is dirtier so the need is more urgent" this winter.
But that was made more difficult by a locked up wheel that has since reduced Spirit's ability to climb steep inclines, Herkenhoff said.
Mars' winter is about five Earth months long, Herkenhoff said, and far colder -- so cold that even toughened electronic circuitry could be destroyed by it. Even without using the motors that propel Spirit -- the rover's biggest power drain -- he said there is barely enough power to maintain minimum heat levels.
Planetary scientists, essentially space geologists, at the USGS in Flagstaff have strong connections with the UA HiRISE team, headed by the UA's Alfred McEwen. His team has been involved in using HiRISE -- High-resolution Imaging Science Experiment -- to choose interesting sites to investigate, including finding a safe landing spot for the UA's Phoenix Mars (lander) Mission.
HiRISE is one of the instruments aboard NASA's Mars Reconnaissance Orbiter, a spacecraft managed by the Jet Propulsion Laboratory.
In this case, they used HiRISE to check out a relatively flat, raised feature in the Gusev Crater known as "Home Plate."
Herkenhoff said getting Spirit in the picture wasn't necessary, but was unavoidable with the camera's ability to capture detail.
Still, it's hard for the untrained eye to pick out the rover. But by comparing this image with other pictures when Spirit wasn't there, Herkenhoff said they were able to identify the rover. Herkenhoff said recent refinements in rendering the color from HiRISE's images also helped.
The rover has its own cameras that have sent back images of its location, but by using the HiRISE images Herkenhoff said crews can do a better job of planning its route.
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