Mars Rover Spirit Heads to Alternate Home

By ALICIA CHANG

LOS ANGELES – The Mars rover Spirit, hampered by a broken wheel, has failed to reach its planned destination and will spend the Martian winter in an alternate site, scientists said Monday.

The solar-powered Spirit was rolling toward the north-facing side of McCool Hill last month to catch some sunshine during the winter when its right front wheel stopped working.

After three failed tries to climb McCool, engineers decided to steer Spirit to a closer slope known as Low Ridge, where it will spend the winter, said principal scientist Steve Squyres of Cornell University.

It’s not the first time Spirit has had trouble with its right front wheel. The wheel previously had an episode of balkiness, but the latest problem is worse because the motor that spins the wheel stopped working.

Squyres said it would take a "miracle" to fix the wheel.

"We are anticipating it will be a five-wheeled rover for the rest of the mission," he said.

After the wheel stopped working, Spirit drove backward while dragging its broken wheel. But the bad wheel kept slipping into a sandy trench on its way toward McCool, said Jacob Matijevic, rover engineering team chief.

Although the alternate site should provide enough sunlight for Spirit, it won’t be as strong as what it would have received perched on McCool Hill, Matijevic said. Low Ridge has only an 11-degree incline compared to McCool, which has a 20-degree tilt.

Scientists believe the Low Ridge slope was created from the remnants of an impact crater. Squyres said the area appears to have salt deposits and thinly layered bedrock.

Engineers are considering directing Spirit to McCool in the spring.

Spirit and its twin, Opportunity, landed on opposite ends of Mars in January 2004. Opportunity is making its way to the giant Victoria crater.

Spirit and Opportunity, managed by NASA’s Jet Propulsion Laboratory, have outlasted their primary missions.

— 

On the Net:

Mars Rovers: http://marsrovers.jpl.nasa.gov/home/index.html