This June 2008 NASA handout shows the Robotic Arm on NASA's Phoenix Mars Lander with a sample of martian soil. NASA scientists said Thursday the agency was extending the Mars mission of its Phoenix lander until the end of September, describing its progress so far as "very successful. "

A full circle panoramic view of Mars taken by NASA's Phoenix Mars Lander is shown in this undated handout photo released to Reuters July 31, 2008. NASA scientists said on Thursday they had definitive proof that water exists on Mars after further tests on ice found on the planet in June by the Phoenix Mars Lander.

This image provided by NASA shows the full-circle panoramic view of the Phoenix Mars Lander taken during the first several weeks after NASA's Phoenix Mars Lander arrived on an arctic plain on Mars in late May. The Phoenix spacecraft 'tasted' Martian water for the first time, Wednesday July 30, 2008.

A 360 degree panoramic view of Mars taken by NASA's Phoenix Mars Lander is shown in this undated handout photo released to Reuters July 31, 2008. NASA scientists said on Thursday they had definitive proof that water exists on Mars after further tests on ice found on the planet in June by the Phoenix Mars Lander.

This NASA handout image, received on June 13, 2008 shows trenches dug by the Robotic Arm on NASA's Phoenix Mars Lander after it delivered the first sample of dug-up soil to the spacecraft's microscope station, taken by the Surface Stereo Imager during the mission's Sol 17 (June 12), or 17th Martian day after landing.

This NASA handout shows an an artist's conception of the Phoenix Mars Lander. NASA scientists said Thursday the Phoenix lander exploring Mars had confirmed water on the planet after analysis of a soil sample from the Red planet's surface.

This image taken July 14, 2008 by the Surface Stereo Imager on Phoenix Mars Lander shows the silver colored rasp protruding from the lander's robotic arm scoop. Minerals in the soil of Mars show it was covered once by lakes and other bodies of water that could have supported life, US researchers reported on Wednesday

This picture released in May 2008 by NASA shows a polygonal pattern in the ground near NASA's Phoenix Mars Lander, similar in appearance to icy ground in the arctic regions of Earth. Water bathed the surface of southern Mars for millions of years, helping to create an environment theoretically capable of nurturing life, according to a new study into the planet's mysterious oceans.