NASA Rover Opportunity Zeroes in on Mars

PASADENA, Calif. (AP) – The rover Opportunity zeroed in on Mars late Saturday night, making its final turn and positioning a heat shield designed to protect it from burning up during a fiery plunge through the planet’s atmosphere.

The turn began about 90 minutes before Opportunity was to land on Mars.

The National Aeronautics and Space Administration warned that communications with the six-wheeled robot would be spotty as it entered and descended through the martian atmosphere. Word of a safe landing could take as long as 22 hours, NASA said.

Opportunity’s twin, Spirit, landed Jan. 3. Spirit began malfunctioning Wednesday, after days of sending pictures and other scientific data, but engineers said they were closing in on the problem that had reduced the rover to spewing gibberish and beeps.

Opportunity was targeted to land 6,600 miles – or halfway around Mars – from Spirit. Together, the twin rovers make up a $820 million mission to determine if Mars ever was a wetter world capable of sustaining life.

Opportunity, like Spirit, must execute a choreographed sequence of events to ensure its safe arrival on Mars. The only difference: Opportunity was to open its parachute 4,500 feet higher than Spirit did to compensate for the higher elevation of its landing site.

Spirit developed problems after working nearly flawlessly for days.

Engineers brought stability to the rover by disabling its flash memory, which is similar to the memory digital cameras use to store pictures, said Orlando Figueroa, director of NASA’s Mars exploration program.

“We made good progress overnight,” project manager Pete Theisinger said during a news conference at NASA’s Jet Propulsion Laboratory. “The rover has been upgraded from critical to serious.”

Spirit resumed transmitting data Friday, but only in limited batches. The malfunction may prevent the rover from taking another drive on Mars for as long as three weeks, Theisinger said.

Despite its woes, scientists said there is still a chance the rover can fully recover.

JPL Director Charles Elachi said other NASA spacecraft, including Voyager, Magellan and Galileo, have recovered from even graver problems.

“I am completely confident, without any hesitation, that I think we will get that rover back to full operation,” Elachi said.

Mission members were able to stop the rover from rebooting its computer – which it had done roughly 130 times – and place it in so-called “cripple” mode to bypass the computer chips that make up its flash memory.

They also succeeded in commanding the robot to sleep after it stayed up two nights in a row when it should have been turned off to conserve power.

The root cause of Spirit’s problems remained elusive. NASA’s inability to reproduce the problem in laboratory software tests suggests that something is awry with the rover’s hardware, Theisinger said.

During its first weeks on Mars, Spirit took thousands of pictures and began its work prospecting the soil and rocks around its landing site. The science work stopped Wednesday.

NASA sent Spirit to Gusev Crater, a broad depression believed to once have contained a lake. It launched Opportunity toward Meridiani Planum, a flat, smooth region relatively free of the reddish dust that cloaks Gusev. Scientists believe Meridiani abounds in a mineral called gray hematite, which typically forms in marine or volcanic environments rich in water.

Not since the 1976 landing of the twin Viking landers has NASA had two working spacecraft on the surface of Mars.

NASA launched two rovers to double its chances of successfully landing on Mars. Just one in three international efforts to land on the Red Planet has succeeded.

The list of failures may include the British lander Beagle 2, which has not been heard from since attempting to set down in December.

Three other spacecraft, two from NASA and one from the European Space Agency, remain in orbit around Mars.

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On the Net:

http://marsrovers.jpl.nasa.gov