NASA's Mars Phoenix Lander can be seen parachuting down to Mars, in this image captured from Nasa's Mars Reconnaissance Orbiter May 25, 2008. The small science probe blazed through the salmon-colored skies of Mars on Sunday, touching down on a frozen desert at the planet's north pole to search for water and assess conditions for sustaining life, NASA officials said. (Xinhua/Reuters Photo)

The flat Martian valley floor is expected to have water-rich permafrost within reach of the lander's robotic arm.

"We can see cracks in the troughs that make us think the ice is still modifying the surface," said Peter Smith, a lead scientist on the project. "We see fresh cracks. Cracks can't be old. They would fill in," he said.

"I'm floored. I'm absolutely floored," said Phoenix Project manager Barry Goldstein of NASA's Jet Propulsion Laboratory in Pasadena, California, as he reviewed the dramatic images.