Published online 12 August 2004 | Nature | doi:10.1038/news040809-15

News

Mars rover snaps panoramic view

Spirit continues its heroic climb up the Columbia Hills.

Spirit sends a rocky postcard home to Earth.Spirit sends a rocky postcard home to Earth.© NASA

When one of your wheels is broken and your batteries are running low, sometimes you just need to stop and take in the scenery.

Spirit, NASA's Mars Exploration Rover, has sent a panoramic postcard from a rocky outcrop about halfway up the 200 metre-high Columbia Hills, the martian mountain range it has been climbing since June.

It reached the viewpoint last week after a tough climb to the crest of the West Spur, which juts out from the side of the hills. The rover cannot cope with gradients steeper than 20° so it took a zig-zag path up the side of the spur and is now studying the geology of an area of rocks dubbed Clovis.

The robot has travelled more than three kilometres from its landing place in the Gusev Crater, and has been rolling for 218 martian days or 'sols', which are slightly longer than an Earth day. Although it has far surpassed its mission lifetime of 90 sols, it is now showing significant signs of wear and tear.

"But it's been a revelation how well everything has worked so far," says Jake Matijevic, one of Sprit's engineers at NASA's Jet Propulsion Laboratory in Pasadena, California.

Driving backwards

About a month ago, the rover's right front wheel began to draw extra electricity from the craft's depleted batteries because of a faulty gearbox. So engineers now steer the craft backwards to take pressure off the injured disc and conserve electricity.

ESA's Mars Express satellite helped Opportunity to send this false-colour image of the interior of Endurance Crater back to Earth.ESA's Mars Express satellite helped Opportunity to send this false-colour image of the interior of Endurance Crater back to Earth.© NASA

The encroaching martian winter means that the solar panels that recharge the batteries during the day are harvesting relatively little light, so the rover can now only work for one or two hours each day.

On 10 September Mars and Earth will be on opposite sides of the Sun, disrupting communications with Spirit. The martian midwinter falls around this time too, so Matijevic says that they may choose to put the robot into hibernation for a week, pointing its solar panels towards the weak Sun to store up energy.

These small sand dunes at the bottom of Endurance Crater are no more than one metre high.These small sand dunes at the bottom of Endurance Crater are no more than one metre high.© NASA

Matijevic hopes that before its winter snooze Spirit will reach the top of the Columbia Hills, where it should get a truly spectacular view of the surrounding area. "I always felt there was quite a bit of extra capability in the rovers," he says.

After that, it will pick its way down the other side to investigate what lies beyond the hills. Orbital measurements indicate that the plains beyond hold unusual rock formations, which will provide rich pickings for the ageing robot geologist.

On the other side of Mars, Spirit's twin rover Opportunity is still exploring Endurance Crater, a 130 metre-wide depression in the Meridiani Planum area. It recently used the European Space Agency's Mars Express orbiter to relay pictures to Earth, the first time the satellite has provided a communications link for the rovers.