Tantalizing Results from Mars Odyssey
Probe Suggests Water Ice Abounds at Martian South Pole

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Watch Odyssey's launch

Odyssey's heat-measuring instruments are providing the first images of Martian terrain in the dead of night. Scientists suspect the collapsed and chaotic terrain shown here may have been caused by the rapid removal long ago of underground water. The dark mesas stand thousands of feet above the lighter canyon floor of a region called Hydaspsis Chaos. Image: NASA/JPL/Arizona State University

March 2, 2002 -- A spacecraft in orbit around Mars has sent back its first provocative glimpses of the planet. The 2001 Mars Odyssey is the first mission to use night-vision technology to peer into dark crevices on Mars. It's also on the prowl for water on the surface of the Red Planet. The spacecraft has been studying the planet for just two weeks, but it's already made some remarkable discoveries. NPR's Richard Harris has the story for Weekend Edition Saturday.

NASA has done a good job landing on Mars, with the Viking and Pathfinder missions. But the space agency has had a lot more trouble putting satellites in orbit around the planet to get a bird's eye view. There were heavy sighs of relief last fall when the Mars Odyssey probe made the trip safely into Mars orbit. And now the payoff: The first images, taken by an infrared camera that looks for small variations in heat, were unveiled Friday at the Jet Propulsion Laboratory in California.

"We see an incredible diversity of landforms, of structures, of textures. We see these dark regions, we see craters, we see mesas, we see rocky places," said Philip Christensen, from Arizona State University, about the first batch of results.

Rocks retain their heat at night, while smaller particles of dust and sand quickly turn cold. This nighttime thermal infrared image shows a dark channel filled with cold, finely grained dust, and a bright rim of rocks surrounding a crater. The rocks were likely blown out of the crater during the initial impact that created it. Image: NASA/JPL/Arizona State University

Christensen's infrared camera can also gaze into dark canyons to reveal what's hidden from ordinary cameras. And the camera allows scientists for the first time to look at the Martian surface at night -- the best way to find warm spots that aren't obvious in the light of day.

"One of the major goals is too look for anomalous hot spots at night -- if Mars still has any volcanic activity, near-surface activity, any near-surface hot spring activity," he said. "With these images, we will actually be able to see that and search for places where there might be near-surface water today."

Finding liquid water on Mars would be a huge discovery. Liquid water could provide habitat for life -- and it could be useful for eventual human explorers. There's much evidence that Mars used to be wet: rocks that look sedimentary, channels that appear to be carved by liquid, and even signs of liquid seeps. But Mars is so cold, chances are any water still on the planet will be ice. William Boynton, of the University of Arizona, has been trying to find ice on Mars for 16 years, but he's been thwarted by the failure of a previous spacecraft. This time, though, he was not to be disappointed. He activated his instrument on board Mars Odyssey, and even before it was rigged up properly, it sent back a surprisingly strong signal.

"The signal we have been getting loud and clear is there is a lot of ice on Mars," Boynton said.

Boynton and his team have been poring over data from Odyssey night and day. What they see, with three different lines of evidence, is an abundance is hydrogen. And that hydrogen is almost certainly in the form of H₂0.

"We have three different instruments that use two different techniques and they're all giving us the same information -- that there's just a lot of hydrogen, a lot of ice, in the southern hemisphere of Mars," he said.

Boynton's instrument measures the composition of the first few feet of Martian soil. He figures that, at the southern end of the planet, that soil is about 1 percent frozen water -- not exactly an ice rink, but still a significant find. Boynton says he can hardly wait to look at the north pole of Mars, but it's currently covered with a frost of carbon dioxide, so he has to wait for that to melt as spring sets in during the next few months.

"There might very well be just as much hydrogen in the northern hemisphere, we just can't see it through the big CO₂ cap that's on top of it," he said. "So we're really looking forward to following this with time, and we'll probably be having a lot more sleepless nights just watching as these data come in."

In Depth

Browse for more NPR stories about Mars exploration.

Read previous NPR coverage of Odyssey.

Other Resources

• Track the Mars Odyssey

• 2001 Mars Odyssey Web site

• More images from Odyssey's thermal mapping mission

• Images from the Mars Global Surveyor

• NASA's Mars Explorations site

• Other NASA missions to Mars

• European Space Agency's Mars mission site

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