- MSNBC - If you're serious about the search for extraterrestrial life,
it's going to take more than rovers and radio telescopes. You may have
to look miles beneath the surfaces of other worlds. Maybe the movie "Armageddon"
got it right: The best astronauts for interplanetary expeditions will be
deep drillers.
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- Last Years's big asteroid movie drew
a Texas-sized share of scorn for its improbable plot, which turned a ragtag
gaggle of oil-rig workers into a team of astronaut-heroes in a matter of
days. But for all its scientific sins, Arizona State University geologist
Jack Farmer hints that the people in charge of planning missions to Mars
could learn a thing or two from Bruce Willis' character.
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- "They're going to have to get some
experience on drilling rigs," Farmer said this week at the annual
meeting of the American Association for the Advancement of Science.
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- For years, Farmer has worked on NASA's
strategies for exploring the Red Planet and for seeking traces of ancient
extraterrestrial life " an endeavor for which he coined the term "exopaleontology."
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- The current theme for the quest on Mars
has to do with water: Did liquid water flow freely over the planet billions
of years ago? Where did it come from, and where did it go? Might the presence
of water have facilitated the development of life on ancient Mars? Does
the planet still exhibit a pattern of water circulation on some level?
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- If there is such a pattern " a "hydrologic
cycle," to use geological parlance " it would have to be active
far beneath the surface, Farmer said. Indeed, a growing number of scientists
say the water that once filled Martian valleys most likely came from underground
hydrothermal systems, rather than from an Earthlike system of rivers, oceans
and rain clouds.
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- "The valleys were carved by flowing
water, but the water sprang forth from beneath the surface and eroded the
channels by a process of sapping,' rather than by runoff of surface water,"
University of Colorado geologist Bruce Jakosky writes in Friday's issue
of the journal Science. "Although this probably requires an ancient
climate warmer than today's, it does not necessarily require an atmosphere
warm enough to allow substantial atmospheric precipitation and runoff."
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- Those words echo the *view of Michael
Malin, the principal investigator for the camera aboard the Mars Global
Surveyor spacecraft now orbiting the planet.
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- Jakosky also points out that Global Surveyor's
thermal emission spectrometer found a large concentration of hematite,
an iron-bearing mineral that forms on Earth only in high-temperature aqueous
systems. "This is compelling evidence for hydrothermal systems on
Mars," he writes. Such hydrothermal systems could have provided a
suitable environment for the development of life on Mars, Jakosky says,
and some form of life may continue to lurk there, if only on the microscopic
level.
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- But how do you test those amazing hypotheses?
One strategy is to take samples from those ancient valleys and flood plains,
in the hope that you can reconstruct the geological and perhaps even the
biological record. The recently launched Mars Surveyor 98 mission is designed
to shoot *penetrators as far as 6 feet below the planet's surface, and
there are other plans to dig and burrow for samples of subsurface soil.
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- [*Sarah Gavit, project manager for the
Deep Space 2 microprobes, explains how the probes will be used during the
Mars Surveyor 98 mission.]
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- In the end, however, explorers may have
to drill thousands of feet into Mars. Indeed, Farmer said that just might
be the main justification for sending humans to Mars, perhaps sometime
within the next 20 years.
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- Mars isn't the only world where scientists
want to go deep: For example, researchers see ample evidence that a briny
ocean lies miles beneath the icy surface of *Europa, one of Jupiter's moons.
Such a body of water would be the No. 1 target in the search for life elsewhere
in the solar system. Some scientists say even *Charon, Pluto's moon, might
have a subsurface ocean. NASA's Jet Propulsion Laboratory already is testing
*robots that might eventually burrow beneath the ice and sample those seas.
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- In all these cases, researchers will
have to deal with the issue of forward contamination: How do you guard
against transferring Earth's organisms to these otherworldly environments?
Ruining your samples would be the least of your problems: You could ruin
an entire global ecology in the process.
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- Avoiding such a catastrophe will require
decades of planning, and an ability to handle the controls with surgical
skill. Hmmm ... come to think of it, maybe a bandoleer-bedecked Bruce Willis
type isn't the right person for the job after all.
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- For more information on the week's developments,
click on the links below. Please send your comments to Space News Editor
Alan Boyle at alan.boyle@msnbc.com
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