From: Michael M. Butler (butler@comp-lib.org)
Date: Thu Dec 13 2001 - 17:40:43 MST
New Mars orbiter gets whiff of possible water
SAN FRANCISCO (Reuters) -- NASA's Odyssey spacecraft, tightening its
orbit around Mars for a mapping mission, has sniffed out big hydrogen
deposits, possibly indicating extensive water ice, according to
project scientists.
Odyssey, which left Earth earlier in the year and slipped into its
initial orbit around Mars in October, is operating as planned and has
started to send back its first bursts of scientific data.
"We think it will be a very exciting winter and spring," James
Garvin, Mars Program scientist at NASA headquarters in Washington,
said Wednesday at a meeting of the American Geophysical Union in San
Francisco.
Scientists have high hopes for the $300 million Odyssey project,
which follows two failed missions to the red planet that had cast
doubt on the space agency's plans to investigate Earth's nearest
planetary neighbor.
A box-shaped craft designed to spend 2-1/2 years circling Mars to
study its climate and geological history, Odyssey was launched in
April and made the interplanetary trip without a hitch.
NASA scientists said the spacecraft was now about two-thirds of the
way through a complex braking process designed to ease it into final
mapping orbit about 250 miles (400 km) above the surface by
mid-January.
Previous setbacks
Odyssey's smooth progress contrasts with its predecessors' problems.
In December 1999, the Mars Polar Lander smashed into Mars' surface
after a false signal caused its engines to shut off too soon. And a
few months earlier, the Mars Climate Orbiter burned up in the
planet's atmosphere because of a mix-up between English and metric
measurements.
But officials have vowed that the Mars program will continue,
envisioning a multiyear series of missions that will ultimately
include landing more rovers on the Martian surface, as well as
setting up the Mars Smart Lander as an on-site laboratory.
Odyssey is expected to begin its primary mission in January, when it
will use various scientific instruments to study the chemical and
mineral composition of the planet.
Red planet could be riddled with underground ice deposits.
A gamma-ray spectrometer will chart the chemical makeup of the
Martian surface, searching for rocks and soil indicative of water in
the distant past. A neutron spectrometer will look for signs of
hydrogen in the soil, a telltale sign of water or ice below the
surface. And an infrared camera will peer at areas on the dark side
of Mars where water or some other liquid may be breaking the surface
today.
On Wednesday, scientists said the first pass by the neutron
spectrometer had revealed evidence of hydrogen in the soil in
northern regions near the pole.
Big swing of the needle
"It is big," Bill Feldman of Los Alamos National Laboratory said,
referring to the magnitude of the instrument's first, preliminary
reading.
Feldman, who is in charge of the neutron spectrometer aspect of the
mission, said the results indicated large amounts of hydrogen on the
surface, a likely sign of water ice.
They "are precisely what you would expect for a very hydrogen-rich
environment," Feldman said.
Scientists know that water exists on Mars but so far have believed it
is mostly frozen in the polar icecaps or drifting about the
atmosphere in thin clouds.
Scientists who have studied images of the Martian surface believe
they have seen evidence that water once flowed there, carving out
deep channels and canyons.
Significant water ice deposits easily accessible on the surface of
the planet would benefit any future Mars mission astronauts and make
it much more likely that life might have existed on the planet.
NASA scientists said they were excited by the initial indications of
hydrogen deposits, describing the readings sent back as clearer, more
definite and much earlier than had been expected.
"We were expecting that it would take many orbits (to determine the
presence of hydrogen)," said Stephen Saunders, a scientist on the
Odyssey project. "But we saw it the very first time."
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