Post by Icarus on Feb 2, 2007 9:50:37 GMT -5
Next Mars lander, Phoenix, will dig into icy surface
Spacecraft to check soil for chemicals that can support life
David Perlman, Chronicle Science Editor
Friday, February 2, 2007
A new spacecraft is being readied for a trip to Mars to excavate the planet's icy soil, seeking a sunlit habitat where life might have flourished in the distant past. It will mark the first time since the famed life-seeking Viking missions 30 years ago that NASA has sent a tool to dig beneath the planet's surface.
The spacecraft, named Phoenix, is scheduled to launch Aug. 3 toward the frigid Martian regions about 800 miles from the planet's North Pole, carrying a sharp-edged robotic shovel for scooping up soil samples saturated with ice for analysis on board.
Mission planners from the University of Arizona and NASA's Jet Propulsion Laboratory hope Phoenix's boom-mounted shovel will reach as far as 3 feet deep, but they acknowledge that layers of solid ice could limit the depth of the dig to barely more than a foot -- still a feat never before accomplished.
Phoenix is undergoing final assembly and readiness tests at the Lockheed Martin Space Systems facility near Denver. On Thursday, Peter Smith of the University of Arizona, the mission's chief scientist, briefed reporters on the mission both at the plant and by telephone.
"We're seeking evidence of an environment where life could exist," Smith said. Although the spacecraft will carry no instruments that could identify living organisms or their remains, "we will be analyzing the soil for chemicals that could feed them," he said.
The mission is certainly not seeking evidence of actual life, Smith said during the briefing. But in a phone call to The Chronicle from the Denver airport afterward, he acknowledged that it could be possible for living microorganisms -- perhaps deep in hibernation just beneath the surface -- to come to life briefly in the feeble sunshine.
"There's always some remote possibility of life existing there even now," Smith said, "but Phoenix might be landing 10 feet away from it, and we'd never know it."
The Phoenix spacecraft's unique shovel will operate for only five to seven hours a day when sunlight warms the planet enough to soften the surface ice. Mounted on an 8-foot arm and aided by a power grinder to pulverize at least some layers of solid ice, it will dig into the ice-encrusted soil to dredge up sand grains, Smith said.
Each shovel load of sand grains mixed with ice will be lifted and tipped into a series of miniaturized analytic instruments. Smith said the materials will be examined by two microscopes, then baked at 1,800 degrees Fahrenheit in eight ovens to separate vapors that will reveal the soil's acidity and saltiness. Other instruments will analyze the vapors for elements essential to life like carbon, nitrogen, phosphorus, sulfur and hydrogen. Detecting at least simple organic compounds in the saturated soil is also possible, he said.
In 1976, the two Viking spacecraft each carried robot digging arms that placed tiny soil samples into three small automated chemical laboratories. Those missions -- the first to land on Mars -- were designed to seek actual living organisms, unlike the Phoenix mission, and found nothing but exotic chemistry. They landed in the arid ice-free mid-latitudes of Mars, however, and in that region, ultraviolet radiation is now known to be so powerful it would certainly destroy any surface life.
That, Smith said, "is why we really want to go where there's a good chance that life could exist."
The landing site for the Phoenix mission has not been set, but two spacecraft now orbiting the planet -- the Mars Reconnaissance Orbiter and Mars Odyssey -- are scouting the far north for flat areas free of boulders. One, not far from a major volcano and tentatively named Green Valley, lies south of the North Pole's permanent ice cap and is a likely spot, Smith said.
The instruments aboard the Phoenix spacecraft and much of its structure are actually derived from two earlier Mars missions that never made it. One was the Mars Polar Lander, an ambitious, highly instrumented venture that reached the planet in December 1999 but vanished -- probably crashing when its landing rockets stopped firing prematurely. The other was a lander scheduled for launch in 2001, but canceled during construction because of cost overruns and technical problems.
Phoenix is in excellent shape and virtually ready to fly, according to Barry Goldstein, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, and Edward Sedivy, the Lockheed Martin flight systems manager.
Unlike several earlier missions whose landings on Mars were cushioned by giant air bags, Phoenix will reach its final target after a nine-month flight across a million miles of space by blasting three sets of thrusters fueled with pure hydrazine to slow down.
After approaching the planet at 12,600 mph, a huge parachute will curb its descent speed to 750 mph and then to 120. When the thrusters fire, Phoenix will slow to 5 mph and settle gently on the surface.
--------------------------------------------------------------------------------
On the Web
Videos of Phoenix's planned fiery descent and landing, plus other elements of the mission, are at phoenix.lpl.arizona.edu/videos.php.
Spacecraft to check soil for chemicals that can support life
David Perlman, Chronicle Science Editor
Friday, February 2, 2007
A new spacecraft is being readied for a trip to Mars to excavate the planet's icy soil, seeking a sunlit habitat where life might have flourished in the distant past. It will mark the first time since the famed life-seeking Viking missions 30 years ago that NASA has sent a tool to dig beneath the planet's surface.
The spacecraft, named Phoenix, is scheduled to launch Aug. 3 toward the frigid Martian regions about 800 miles from the planet's North Pole, carrying a sharp-edged robotic shovel for scooping up soil samples saturated with ice for analysis on board.
Mission planners from the University of Arizona and NASA's Jet Propulsion Laboratory hope Phoenix's boom-mounted shovel will reach as far as 3 feet deep, but they acknowledge that layers of solid ice could limit the depth of the dig to barely more than a foot -- still a feat never before accomplished.
Phoenix is undergoing final assembly and readiness tests at the Lockheed Martin Space Systems facility near Denver. On Thursday, Peter Smith of the University of Arizona, the mission's chief scientist, briefed reporters on the mission both at the plant and by telephone.
"We're seeking evidence of an environment where life could exist," Smith said. Although the spacecraft will carry no instruments that could identify living organisms or their remains, "we will be analyzing the soil for chemicals that could feed them," he said.
The mission is certainly not seeking evidence of actual life, Smith said during the briefing. But in a phone call to The Chronicle from the Denver airport afterward, he acknowledged that it could be possible for living microorganisms -- perhaps deep in hibernation just beneath the surface -- to come to life briefly in the feeble sunshine.
"There's always some remote possibility of life existing there even now," Smith said, "but Phoenix might be landing 10 feet away from it, and we'd never know it."
The Phoenix spacecraft's unique shovel will operate for only five to seven hours a day when sunlight warms the planet enough to soften the surface ice. Mounted on an 8-foot arm and aided by a power grinder to pulverize at least some layers of solid ice, it will dig into the ice-encrusted soil to dredge up sand grains, Smith said.
Each shovel load of sand grains mixed with ice will be lifted and tipped into a series of miniaturized analytic instruments. Smith said the materials will be examined by two microscopes, then baked at 1,800 degrees Fahrenheit in eight ovens to separate vapors that will reveal the soil's acidity and saltiness. Other instruments will analyze the vapors for elements essential to life like carbon, nitrogen, phosphorus, sulfur and hydrogen. Detecting at least simple organic compounds in the saturated soil is also possible, he said.
In 1976, the two Viking spacecraft each carried robot digging arms that placed tiny soil samples into three small automated chemical laboratories. Those missions -- the first to land on Mars -- were designed to seek actual living organisms, unlike the Phoenix mission, and found nothing but exotic chemistry. They landed in the arid ice-free mid-latitudes of Mars, however, and in that region, ultraviolet radiation is now known to be so powerful it would certainly destroy any surface life.
That, Smith said, "is why we really want to go where there's a good chance that life could exist."
The landing site for the Phoenix mission has not been set, but two spacecraft now orbiting the planet -- the Mars Reconnaissance Orbiter and Mars Odyssey -- are scouting the far north for flat areas free of boulders. One, not far from a major volcano and tentatively named Green Valley, lies south of the North Pole's permanent ice cap and is a likely spot, Smith said.
The instruments aboard the Phoenix spacecraft and much of its structure are actually derived from two earlier Mars missions that never made it. One was the Mars Polar Lander, an ambitious, highly instrumented venture that reached the planet in December 1999 but vanished -- probably crashing when its landing rockets stopped firing prematurely. The other was a lander scheduled for launch in 2001, but canceled during construction because of cost overruns and technical problems.
Phoenix is in excellent shape and virtually ready to fly, according to Barry Goldstein, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, and Edward Sedivy, the Lockheed Martin flight systems manager.
Unlike several earlier missions whose landings on Mars were cushioned by giant air bags, Phoenix will reach its final target after a nine-month flight across a million miles of space by blasting three sets of thrusters fueled with pure hydrazine to slow down.
After approaching the planet at 12,600 mph, a huge parachute will curb its descent speed to 750 mph and then to 120. When the thrusters fire, Phoenix will slow to 5 mph and settle gently on the surface.
--------------------------------------------------------------------------------
On the Web
Videos of Phoenix's planned fiery descent and landing, plus other elements of the mission, are at phoenix.lpl.arizona.edu/videos.php.