Space

Suddenly, 'Spirit' falls silent

NASA's Spirit rover has stopped transmitting data from Mars in an ominous turn that baffled engineers and sent them scrambling desperately Thursday to figure out what brought the mission to a potentially calamitous halt.

NASA received its last significant data from the unmanned Spirit early Wednesday, its 19th day on the surface of Mars. Since then, the six-wheeled vehicle has sent either random, meaningless radio noise or simple beeps acknowledging it has received commands from Earth.

The project manager, Peter Theisinger, described the problem as "a very serious anomaly on the vehicle."

Theisinger said a team had met through Wednesday night into the morning looking for answers at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"There was no one single fault that explains all the observables," he said at a news conference.

The mission scientists had yet to decide on their "go-forward activities," he said.

Deputy project manager Richard Cook said beeps from the rover were picked up on Wednesday evening by a global surveyor that is orbiting Mars.

"But it was a random pattern of zeros and ones," he said, adding that the rover's radio was on but that Spirit was not sending information.

"We don't know what is the state of the software," he added, saying if it were a software problem, it could be fixed by beaming corrections across more than 100-million miles of space. A hardware problem would be more difficult, Cook said.

The six-wheeled robot had been scheduled Thursday to grind away a tiny area of the weathered face of a sharply angled rock called Adirondack. Examination of the material could offer clues to Mars' past.

Spirit is half of an $820-million mission. Its twin, Opportunity, is scheduled to land on Mars early Sunday.

Wednesday, NASA said ground controllers were able to send commands to the rover and received a simple signal acknowledging they had been received. But they did not receive the scientific and engineering data they had expected.

Project managers said similar problems occurred several times during an earlier Mars expedition.

- Information from the New York Times and the Associated Press was used in this report.

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