No More Roving for Spirit; Stationary Science Ahead

[/caption]
The Spirit rover’s driving days are likely over, as efforts to extricate the rover have been curtailed. “We do not believe that Spirit is extractable,” said Doug McCuistion, director of NASA’s Mars Exploration Program. But mission managers stressed that today is not a day of loss at this point, as they hope to continue to make some exciting scientific observations. However, the rover needs to be tilted to gather as much sunlight as possible in order to survive the Martian winter. John Callas, project manager for the MER mission told Universe Today at today’s press briefing that time is short. “We estimate about three weeks of driving activity, and we can’t drive every day,” he said. “So there are just a handful of drives left before there is insufficient power to continue.”

Callas added that around the March-April time frame will be the last images and data the rover can transmit before going into hibernation for the winter.

Spirit has been embedded in a sandtrap for 10 months, and the rover team has been engaged in an ambitious process to extricate the rover. They’ve encountered numerous setbacks, including the loss of use of an additional wheel, making it a four-wheeled rover. (Spirit’s right front wheel has not worked for a couple of years, now the right rear wheel has lost functionality).

“Spirit is in a golfer’s worst nightmare, stuck in a sand trap that no matter how many strokes you take you can’t get out of,” said McCuistion.

Pointing the rover’s solar panels towards the sun is critical if the rover is to survive. In past winters, the movable rover has been able to be positioned to allow for maximum sun-gathering but the current embedding of the rover has left it with an unfavorable tilt, 9 degrees to south, when they really want a level rover — or even better — tilted to north.

Rover driver Ashley Stroupe said the rover is now pitched flat and rolled to left. “We want to try to pitch it forward and roll right for best winter survival.”

The last few drives were aimed at trying to improve the rover’s position, and were mildly successful.

“We’ve aimed toward improving northerly tilt,” said Stroupe. “Spirit is sitting in a small crater with the rim behind her, so as it moves backwards, it is slowly climbing up, providing more tilt. On the last drive saw 1-2 degree improvement in tilt.”

In recent drives, the rover has moved approximately 20 centimeters. The team can also attempt to rotate the rover in place, so that the roll isn’t pointed as much towards the south as it currently is.

Should they be successful, and if the rover survives the winter, the science team has some exciting prospects of continuing science with Spirit.

“We have hope that Spirit will survive this cold dark winter that she has ahead of her,” said MER principal investigator Steve Squyres. “The bottom line is we’re not giving up on Spirit.”

Squyres said they are most excited about tracking the radio signal from Spirit in order to determine if Mars has a solid or liquid core. “This is something totally new, something we’ve never done,” Squyres said. “If we can accurately determine the rover’s motion in space in three dimensions, we can see the motions of Mars in orbit and track it precisely, then we can characterize the wobble very precisely. The way Mars wobbles depends on its internal structure. If Mars has a solid core of iron, will wobble one way but if it has a liquid molten core it will wobble another way. We should be able to do this by tracking the stationary rover for six months.”

Squyres said the team is finding new tricks on how to use a stationary rover. Additionally, they should be able to characterize the odd soil at the Home Plate region, and characterize the interactions between the atmosphere and the surface of Mars.

“We’re not giving up on Spirit and we’ll keep squeezing as much science out of the rover as we can,” Squyres said. “We feel there is a lot of really exiting science yet ahead.”

Source: Press briefing