Satellite confirms water on Mars

Satellite confirms water on Mars

Meanwhile, Spirit rover slowly sends data home

New York Times, Associated Press, Los Angeles Times

Saturday, January 24, 2004

European scientists said Friday that they had made the first direct detection of water in the form of ice on the surface of Mars, detecting molecules vaporizing from the Red Planet’s south pole.

The discovery was made by the infrared camera of the European Space Agency’s Mars Express satellite, which began orbiting the planet Dec. 25.

Meanwhile, the Spirit rover, the American spacecraft that landed on Mars on Jan. 3, sent limited data back to Earth early Friday after being virtually silent for about two days, NASA’s Jet Propulsion Laboratory announced.

The quest for water on Mars, which could indicate life, has fascinated scientists for centuries.

Scientists have long believed the planet’s poles contain frozen water, but previous findings, including NASA’s Mars Odyssey orbiter’s 2001 evidence of large amounts of ice, were based more on inferences, European scientists said.

While the Mars Odyssey has indirectly shown the presence of water at the pole using temperature monitors, the European camera has for the first time been able to “literally map the polar cap” using infrared technology that shows where water molecules are present, said scientist Jean-Pierre Bibring.

“You look at the picture, look at the fingerprint, and say this is water ice,” said agency scientist Allen Moorehouse. “This is the first time it’s been detected on the ground. This is the first direct confirmation.”

A National Aeronautics and Space Administration official said Friday that the findings by the European agency were “not news.”

But James Garvin, lead scientist for NASA’s Mars exploration program, said Mars Express had offered further confirmation of what scientists have long known: “Mars is a water planet.”

“In terms of the impact, that’s wonderful results,” Garvin said. “It’s instant science, and I think the science community is going to want some time to think about what that means in the context of what we’re learning.”

If Mars once had surface water, it had the potential to support life, although members of the European project have stressed that it was too early to draw conclusions.

The European Space Agency’s Mars Express orbiter is part of Europe’s first mission to Mars. It has failed to pick up a signal from its surface probe, the British-made Beagle II, which had been scheduled to land Dec. 25.

The latest round of Martian exploration, which also includes NASA’s twin rovers, Spirit and Opportunity, are using highly sophisticated instruments to map the mineralogical makeup of the planet’s surface and search for evidence of past water activity.

Spirit repair uncertain

That effort received a boost Friday when NASA received data from the Spirit rover for the first time in about two days, ending fears its mission might have come to a calamitous halt.

Spirit sent back about 30 minutes worth of engineering data. That was enough to tell controllers at the Jet Propulsion Laboratory in Pasadena, Calif., that all its major subsystems were intact and operating but not enough to tell them what was wrong with it and why it stopped communicating in the first place.

Engineers do not yet know how long it would take to repair Spirit, or even if it could be repaired.

“I expect that we will not be restoring functionality to Spirit for many days, perhaps even for a couple of weeks, even in the best of circumstances,” said project manager Pete Theisinger.

“We have a serious problem,” he said, but the vehicle was in no immediate danger. It will be stable “for an extensive period of time that will allow us to work on it.”

“The chances that it will be perfect again are not good,” Theisinger said. “The chances that it will not work at all are also low.”

Craft in ‘fault’ mode

The first step toward understanding Spirit’s malfunction began Friday at 7:02 a.m. CST when laboratory controllers used the Deep Space Network antennas outside Madrid, Spain, to send the rover a command to phone home. Spirit responded at 7:26 a.m. CST, sending back a 20-minute message containing information on its system status.

But the data was transmitted by the rover’s low-gain antenna — used when the craft detects a problem and goes into “fault” mode — and the data rate was only 120 bits per second. When the craft is using its high-gain antenna, by contrast, the data transfer rate is greater than 11,000 bits per second.

Later, there was a 10-minute session, again at the slow rate, with additional status data.

Those transmissions indicated that Spirit’s on-board computer had been rebooting itself repeatedly since Wednesday morning — at least 60 times by Friday morning. Each time the computer woke up from the reboot, Theisinger said, it would discover a condition that would cause it to wait anywhere from 15 minutes to 60 minutes, then reboot again.

Apparently the craft is seeing a different reason to reboot each time, he said. That fact is very confusing to controllers trying to trace the problem.

The data also indicated that Spirit was not going into its sleep mode at night. The craft is programmed to halt most of its activities during the long, cold Martian nights to conserve its batteries. By continuing to operate during planned sleep periods, the rover risks depleting the batteries.

That is not a significant problem, Theisinger said, because the batteries could be recharged even after they were fully depleted. He said it would be better for the team if the rover did not reach such a state, “but we can cope with it if it does.”

At the end of the day on Mars, the team sent Spirit a command telling it to go to sleep for the night so that the batteries could recharge. But engineers do not yet know whether the craft received the command or acted upon it.

Opportunity landing today

At the same time, the Opportunity rover was streaking toward Mars for its scheduled landing at 11:05 p.m. CST today. It will be touching down in Meridiani Planum, halfway around the planet from Spirit’s Gusev Crater landing site.

Half of the team of 300 scientists and engineers that has been monitoring Spirit on Mars will split off to take charge of Opportunity.

Controllers can do little today, however, except wait for Opportunity to reach Mars. All its actions are preprogrammed in its on-board memory. But controllers are working feverishly to understand what went wrong with Spirit to prevent the same thing from happening to its twin.