June 20, 2008 NASA believes ice was found on Mars

LOS ANGELES (AP) - It hasn't found the salt and tequila that David Letterman joked about the other night, but scientists now believe NASA's Phoenix Mars lander has discovered ice on the Red Planet.

The robot lander exposed chunks of bright material while digging a trench in the Martian arctic. The mission's lead investigator says because the white stuff later vanished, it must have been frozen water that vaporized after being exposed. Peter Smith of the University of Arizona says that's "perfect evidence that it's ice." He points out salt can't evaporate like ice.

The lander is studying whether the arctic region of Mars could be habitable. The probe is using its robotic arm to dig up soil samples and bake them in an oven for further analysis.

The arm also has run into a hard surface while digging another trench. Scientists now hope they've uncovered an icy layer instead of just a few chunks of frozen water.