| LOS ANGELES
LOS ANGELES The Mars Phoenix Lander has found
ice on the surface of the Red Planet, triumphant NASA
scientists said on Thursday, a key discovery for the spacecraft
as it searches for water and signs of life on Earth's closet
The proof came in a series of pictures sent back by Phoenix
of a trench it dug with its robotic arm at the arctic circle of
Mars, showing dice-sized chunks of white material that are seen
to melt away over the course of several days.
"It is with great pride and a lot of joy today that I
announce we've found the proof we've been seeking that this
really is water ice and not some other material," mission
principal investigator Peter Smith, of the University of
Arizona, said at a press conference.
The presence of water on Mars is crucial because it is a
key to the question of whether life, even in the form of mere
microbes, exists or has ever existed on Mars. On Earth, water
is a necessary ingredient for life.
Scientists first discovered what they believed was a vast
sheet of ice under the barren surface of the Martian north pole
in 2002, when the Mars Odyssey Orbiter detected it through a
hydrogen analysis while circling the planet.
Phoenix landed on May 25 and uncovered the white chunks
when it dug a trench a few inches into the soil but NASA was at
first cautious in pronouncing it ice because of the possibility
that it could be salt.
But the sequence of photographs showed about eight
dice-sized chunks slowly vanishing, confirming for the
scientific team at about noon PDT (1900 GMT) on Thursday that
it was water ice.
"It was just so incredibly convincing," Smith said of
seeing the images for the first time. "There was no argument to
be made anymore and we all just kind of applauded."
Though the scientists pronounced themselves "thrilled" with
the discovery, it is only the first step in the primary mission
of Phoenix to determine whether water has flowed on Mars and if
life exists on the planet at any level.
"Now we know for sure that we are on an icy surface and can
really meet the science goals our mission," Smith said. "I am
just sitting on the edge of my chair, really, waiting to find
out what (our instruments) can tell us."
Over the next several weeks the science team will analyze
the ice and soil to determine its geologic history and look for
"The fact that there's ice there doesn't tell you anything
about whether its habitable," Smith said. "The ice may be
always in a frozen state and with ice in a frozen state and no
food, that's not a habitable zone.
"Its really the modern history of these plains we're here
to unravel," he said.
The $420 million lander spent 10 months journeying from
Earth to Mars and has already analyzed soil samples scraped
from the surface and put into its onboard laboratory.
(Additional reporting by Will Dunham in Washington; Editing
by Bill Trott)