The Mars Odyssey continues to churn out compelling data, particularly from thermal infrared gear that creates a temperature map of the planet. Today, some 40 percent of Mars has been imaged using that instrument, Saunders said.

"I expect that we will get on the order of 200 percent or more as we complete day and night surveys. Perhaps nighttime coveragewe should do it twice," Saunders said.

One of the things that scientists are looking for at night: Areas that are unusually warm, warmer than they should be. "It would very interesting to catch a volcanic eruptionor a warm spring thats bubbling to the surface of Mars using thermal imaging," Saunders said.

Mars Odyssey has found the red planet loaded with subsurface hydrogen believed to be in the form of water ice.

On arrival at the planet, the spacecraft detected hydrogen buried just below the Martian terrain in the southern hemisphere.

In the northern hemisphere, as Mars Odyssey revved up its operations, the seasonal cap was covered with carbon dioxide. That prevented spacecraft sensors from detecting hydrogen resources. Sensor sweeps of both north and south hemispheres have now revealed both areas rich in hydrogen.

"We dont really know if were looking at just the top of a huge, deep reservoir of water. We can only see down a couple of meters. There are good arguments either way that there might be a very thick deposit layer of ice or it might be very thin," Saunders speculated. "Right now, the amount of water that is implied is on the order of 35 to 50 percent by mass," he said.

Saunders reviewed both findings from Mars Global Surveyor, as well as Mars Odyssey.One surprise from Mars is the role of dust devils that routinely modify the planet's terrain.

"Theyve been caught in action. Its a process that is slow acting and not very potent in any one year. But given a billion years it can do a lot of work on the landscape," Saunders said.

"I think weve got a culprit for what has done a lot of the change that we see on Mars," the JPL Mars Odyssey scientist said.

Continuing to be one of the most intriguing finds on Mars are apparent gullies found on crater walls. These features appear to some scientists as evidence for very recent outflows of water.

"At present, our information suggests that they form on polar facing slopesslopes that get the least amount of sunlight. In my opinion, the distribution of these is where you would expect ground ice to be stable. You wouldnt expect it on sunny slopes that are facing toward the equator," Saunders said.

"So the big issue if it is water gushing out -- whats causing the water to melt?, Saunders said. "With thermal imaging, we might catch one of these things in action," he said.

Photo scans of Mars have also identified older gullies. Places on Mars have been spotted where rather large outflows appear to stem from these features.

"So this type of feature is not just isolated to bullies on the walls of craters, Saunders said.

Saunders took time to advise on the "Face on Mars," a feature held by some that is an artificial leftover from a past civilization on Mars.

The U.S. Viking spacecraft in 1976 snapped a picture of this area, "and that started the whole brew-ha-ha," Saunders said. Subsequently, both Mars Global Surveyor and Mars Odyssey have imaged the so-called Face.

"I think I can assure everybody but the true-believers that NASA hasnt altered the Face on Mars in any way. Its a natural geologic feature," Saunders said.

The Mars data set does include things that are hard to explain, but are completely natural features, he concluded.