NASA Gets Signals From Mars Rover

NASA received data from the Spirit rover Friday morning for the first time in two days, ending fears that the Mars mission may have come to a calamitous halt. But an official said the rover's condition remains "critical" and restoring it to full function could take weeks.

The six-wheeled rover communicated for 10 minutes at about 4:30 a.m. and transmitted some data for 20 minutes about an hour later, officials said in statements early Friday.

"The spacecraft sent limited data in a proper response to a ground command, and we're planning for commanding further communication sessions later today," said Pete Theisinger, rover project manager at NASA's Jet Propulsion Laboratory.

In effect, scientists said, the computer onboard is sensing a problem or problems and repeatedly trying to reboot - about 60 times since Wednesday. The problem could be in software or hardware, Theisinger said.

The rover can stay in its current condition for some time while scientists work on the problem, he said. Asked how he would rank its condition if it were a patient in a hospital, he said, "critical."

But Theisinger said that most likely that things won't be back to normal "for many days, perhaps a couple of weeks, even under the best of circumstances."

Officials said Friday's signals were received by NASA's Deep Space Network antenna complex near Madrid, Spain.

Since Wednesday, its 19th day on Mars, the Spirit had sent back to Earth only meaningless radio noise or simple beeps acknowledging receipt of commands.

Among the possible causes: a corruption of its software or computer memory. If the software is awry, NASA can fix it from Earth by beaming patches across more than 100 million miles of space or by rebooting the rover's computer. But if the problem lies with the rover's hardware, the situation would be far more grave - perhaps beyond repair.

Baffled scientists were still working to pinpoint the trouble Friday morning.

"It is precisely like trying to diagnose a patient with different symptoms that don't corroborate," said Firouz Naderi, manager of NASA's Jet Propulsion Laboratory Mars exploration program.

Spirit is one-half of an $820 million mission. Its twin, Opportunity, is expected to land on Mars late Saturday. The twin rovers are supposed to examine the Red Planet's dry rocks and soil for evidence that it was once wetter and more hospitable to life.

Until Wednesday, Spirit had functioned almost flawlessly and NASA scientists and engineers had been jubilant.

Cushioned by its air bags, the rover made a bull's-eye landing, surviving what was by far the most dangerous part of the mission - the descent through the atmosphere at 12,000 mph. Then on Jan. 15, in another nail-biting moment for NASA, the rover safely rolled down a ramp onto Mars' ruddy soil without becoming snagged.

It has snapped thousands of pictures, including breathtaking panoramic views and microscopic images of the Martian soil. It also carried out preliminary work analyzing the minerals and elements that make up its surroundings.

The problem surfaced while Spirit was preparing to resume analysis of its first rock, just a few yards from where it landed.

Early Thursday, NASA initially heard nothing from Spirit that would indicate it was in "fault mode," a state that the rover enters by itself when it has experienced a problem. Later, NASA sent a command to Spirit as if it were in fault mode, anyway. Spirit acknowledged with a beep that it received the command, indicating an onboard problem. That puzzled engineers.

The rover had since missed several scheduled opportunities to communicate, both directly with Earth and by way of two NASA satellites in orbit around Mars. It finally communicated at 4:34 a.m. Friday, about 90 minutes after it "woke up" for the day, officials said. At 5:26 a.m., data was sent at a faster rate for 20 minutes.

The rover's radio appeared to be working, and it continued to generate power from the sun with its solar panels. Spirit's internal clock also was running and had roused the rover several times on cue.

JPL director Charles Elachi said that once NASA receives engineering signals, "we can do a diagnostic and understand what happened, what are the corrective actions that need to be done and how do we bring it carefully and thoughtfully to its normal operation mode."

Initially, engineers believed bad weather on Earth - a thunderstorm near a Deep Space Network antenna in Australia - had caused the communications glitch. But weather was later discounted as the source.

Meanwhile, Europe's Mars lander has been missing since its deployment last month, but its orbiter Friday sent confirmation of water ice at the south pole.