It looks like the Phoenix Mars Lander may have hit "pay dirt."

Dice-size crumbs of white material have vanished from inside a trench that was dug by the Lander just days ago. Scientists are convinced that the material was frozen water that vaporized after digging exposed it.

"It must be ice," said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice. There had been some question whether the bright material was salt. Salt can't do that."

Phoenix is using its robotic arm to dig up soil samples, and scientists have been hoping it would find frozen water. The robotic arm enlarged a trench, nicknamed "Dodo-Goldilocks" on June 15, during the 20 th Martian day, which exposed the white material. Several chunks of the "white stuff" were gone when Phoenix looked at the trench early Friday.

"This is what this mission was sent to find out. Now, it'll go about analyzing the composition of the ice and characterizing the surroundings," said Steve Lee, curator of planetary science at the Denver Museum of Nature & Science.

Also on Thursday, after digging in a different trench, the robotic arm hit a hard surface that has scientists excited about possibly uncovering an icy layer. The hard layer is the same depth as the ice layer in "Dodo-Goldilocks."

Phoenix landed near Mars' north pole on May 25. The $420 million mission is planned to last 90 days.