/ 8 January 2004

Raising Spirit on Mars

Nasa is delaying rolling its Spirit rover off the spacecraft that brought it to Mars and on to the Red Planet’s rocky soil in order to give engineers more time to clear its path.

The earliest the six-wheeled Spirit will roll on to the Martian landscape is January 14, or about three days later than originally planned. Further delays of one or two days remain possible.

That has made mission members eager to get Spirit moving even more anxious.

“We are champing at the bit to get this puppy off the lander and get driving,” said Art Thompson, a robotics engineer on the $820-million double mission.

Even while perched atop its lander, Spirit has begun doing science work, including snapping high-resolution pictures of its immediate surroundings.

Initial analysis of those images by scientists suggest the landing site inside Gusev crater is not the pristine dry lake bed scientists originally had hoped.

That indicates the robotic explorer’s hunt for geological evidence that the planet once was a wetter place conducive to life might be

more difficult than expected.

The Mars Exploration Rover project includes a second, identical rover. That one, named Opportunity, is scheduled to arrive on Mars on January 24, three weeks after Spirit landed.

The Spirit delay gives engineers time to further retract portions of the now-deflated air bags that cushioned the golf cart-sized rover’s landing. Two pieces of the air bag partially block the ramp that mission members want the rover to follow.

“As soon as we get that air bag out of the way, we’re good to go,” said Arthur Amador, mission manager for Spirit‘s fifth Martian day on the surface.

Spirit, swaddled in its air bags, bounced about 25 times after hitting the surface of Mars, said Rob Manning, manager of the entry, descent and landing portion of the mission. On its first bounce, Spirit rose an estimated 8m.

“It was a pretty friendly bounce,” Manning said.

Spirit came to a rest to the south of a cluster of impact craters seen in the three images its lander snapped in the seconds before landing.

“We could go explore those,” Manning said.

Spirit was to perform a “lift and tuck operation” to raise the blocked ramp and further draw in the bits of deflated air bag. Nasa waited to learn on Thursday if the operation was a success.

If it fails, Spirit can roll down either of two other ramps.

Those manoeuvers would require the rover to perform a robotic pirouette, however, to ensure it faced the right direction.

Scientists have received the first data from Spirit‘s mini-thermal emissions spectrometer, which determines the mineralogical composition of the rocks and soils it views.

Once the readings are interpreted, probably over the next few days, they should help scientists pick the first targets Spirit will investigate close-up.

Scientists selected Spirit‘s landing site because they believed the broad crater once contained a brimming lake — the type of place that may have been hospitable to life. If that was the case, Spirit should be seeing a flat plain rich in fine-grained sediments, said Ray Arvidson of Washington University, the mission’s deputy principal scientist.

“That’s not what we’re looking at,” Arvidson said.

Spirit‘s first look suggests if the landing site was ever a lake bed, it has been significantly altered by other geologic processes.

What they might have been remains the subject of intense debate among mission scientists. — Sapa-AP

On the net: marsrovers.jpl.nasa.gov