Hobbled and old, Mars rover done roaming

LOS ANGELES – After six highly successful years of exploring the red sands of Mars, NASA’s rover Spirit will rove no more.

With its six wheels stuck in powdery sand and two wheels no longer working at all, the resilient little explorer will become a fixed, immobile scientific observatory – if it can survive the harsh temperatures of the upcoming winter.

“Its driving days are likely over,” Doug McCuistion, director of NASA’s Mars Exploration Program, said Tuesday. “Its contributions will continue” if it can be re-awakened after what could be a six-month hibernation during the Martian winter.

If Spirit can be resuscitated, researchers will use it to attempt to answer one of their most pressing questions: whether the planet has a solid iron core or a liquid one. If the vehicle can’t be revived, it will still have far surpassed scientists’ original expectations and its design life of three months, traveling nearly 12 miles across the barren surface of Mars and finding strong evidence that water once altered the planet’s terrain.

Spirit’s twin, Opportunity, is still moving across the Martian surface farther north nearer the equator and on the other side of the planet, and continues to send back valuable data. Its efficiency has been degraded by a buildup of dust on its solar panels, but engineers are hoping for gusts of wind that will clear the dust.

Opportunity has successfully weathered every Martian winter so far because “it is in a different thermal environment,” McCuistion said, and the JPL team that controls it doesn’t expect any troubles for it this winter. “Its environment is way more benign,” he said.

Spirit’s problems began 10 months ago as it was driving toward a pair of volcanic features named Von Braun and Goddard in the southern hemisphere. Its wheels broke through the thin Martian crust in the area – described as much like the crust on a creme brulee dessert – and sank into a powdery sand unlike any the two rovers had encountered before. Breaking free proved difficult because one of the rover’s six wheels had broken down three years earlier and had to be dragged along the ground.

A second wheel became immobilized during the extrication attempts, leaving the vehicle with three good wheels on its left side and only one on its right.

About a week and a half ago, with winter approaching, the team shifted its emphasis from extrication of the rover to positioning it so that its solar panels will receive more sunlight.