U.S. Waiting To Hear From Mars
Anxious NASA engineers were trying to diagnose and possibly patch up their ailing robotic patient after the Spirit rover stopped transmitting data from Mars.
NASA hoped communication with the six-wheeled rover would resume Friday morning after two days without receiving any significant data.
"We're a long way from writing this thing off," said project engineer Dr. Randy Wesson.
Since Wednesday, its 19th day on Mars, the Spirit has sent back to Earth only meaningless radio noise or simple beeps acknowledging receipt of commands.
"We know it's able to receive commands, process commands and then transmit a tone back to Earth, but for some reason it's not talking," said Wesson. "We're trying to figure out why."
Among the possible causes: "It could be a command problem, it could be something to do with the flight software on board the vehicle, or it could be a hardware problem, and we need to be able to track down which one of those it is," said Wesson.
If the problem lies with the rover's hardware, the situation could be beyond repair.
Baffled scientists struggled to pinpoint the trouble.
"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.
Officials said the next best opportunity for actual data to come from the rover was between 6 a.m. and noon EST Friday.
Wesson said there's a duplicate of the Rover at JPL, and it's being used to diagnose the problem.
"We will put in the program that it was running and feed it the same set of commands, and see if we can get it to "safe" — to shut down — and once we can duplicate the failure mechanism, then we can figure out what set of commands we need to do to wake it back up," he said.
Spirit is one-half of an $820 million mission. Its twin probe, 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.
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.
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 mission's main scientist, Steven Squyres of Cornell University, cautioned that communications problems are common on spacecraft.
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 has since missed several scheduled opportunities to communicate, both directly with Earth and by way of two NASA satellites in orbit around Mars.
Preliminary indications suggested the rover's radio was 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.
Engineers hoped to receive engineering data from Spirit by early Friday, JPL director Charles Elachi said.
"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," Elachi said.
In New York, Jim Garvin, NASA's lead scientist for Mars exploration, said on CBS' Late Show with David Letterman that scientists have "gotten a heartbeat" from the rover.
He said the team was "communicating with it at very low rates to tell it how to wake itself back up."
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.