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ZL2VAL > SPIRIT 08.01.04 12:40l 124 Lines 5333 Bytes #999 (0) @ WW
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Subj: Rocks give glimpse of Mars' past
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Sent: 040108/1017Z @:ZL2AB.#46.NZL.OC #:32958 [New Plymouth] FBB7.00g $:32958_Z
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : SPIRIT@WW
Rover mission aims to find if life exists beyond Earth
By Chris Kridler
FLORIDA TODAY
Jan 7, 2004
PASADENA, Calif. -- The photos trickling out of the Mars rover
Spirit are a lot more than an $820 million scrapbook.
To an untrained eye, the images may look like just a bunch of
nondescript rocks. But the pictures, combined with up-close analysis
of those rocks, may hold stunning answers to questions about the
origins of life on our own planet.
They might also be the key to future missions, even human ones, to
Mars.
"The reason that rocks are important is that, if you want to read
about an ancient civilization here on Earth, you go and read history
books. If you want to read the history of a planet, you read it in
the rocks," Mars program manager Firouz Naderi said.
"Now, the key thing is to take with you the tools that would allow
you to read the rocks," he said at NASA's Jet Propulsion Laboratory.
The rovers have those tools, and once they start rolling around on
the surface, they'll produce a lot more than photographs.
The rovers aren't digging for water itself. They are analyzing rocks
for evidence they formed in water.
Evidence that water once flowed on Mars would mean the planet might
have been favorable to the existence of life. Future missions can
look for fossils where the rovers find water-related rocks.
It's difficult to describe the entire red planet based on four
landing sites -- the two Viking landings in the 1970s, the
Pathfinder mission in the '90s, and now the first rover.
"We're sampling the same land surface area as on all of the Earth,"
said rover project scientist Joy Crisp. "So can you imagine trying
to characterize, with four robotic missions, what the whole planet
is like?"
It would be like landing spacecraft in the Nevada desert, the
Italian hills, Antarctica and the Costa Rican rain forest and trying
to come up with one theory to explain Earth's history.
Even a mile could make a tremendous difference in what the
spacecraft sees and what people conclude. And Mars missions have
been limited by the need for safety; no mountains have been explored
yet.
Spirit is in the middle of Gusev Crater, which may have been a lake.
Opportunity will land on the other side of the planet, on Meridiani
Planum, where minerals suggest water once existed.
"The interesting thing about these two missions, these rover
missions, is that we're going to the ancient part of Mars, where we
haven't gone before," Crisp said.
"So we're going to be looking at 3 billion- to 4 billion-year-old
rocks, and that's going to tell us about the early planet's history,
which may have been similar to the Earth's early planet history."
Results from the Mars rovers will fit NASA's overall objective,
Naderi said: to answer the question of whether life exists outside
of Earth.
Powerful space telescopes look beyond our solar system and try to
draw conclusions about whether life could exist elsewhere by
identifying materials in distant star systems.
In Earth's neighborhood, robots do the exploring. The most likely
candidates for life are Mars and the icy Europa, one of Jupiter's
moons, which may hide an ocean beneath its surface.
Robotic missions may help pave the way for human exploration.
The challenges of a human mission to Mars are great. It's going to
be expensive. Better propulsion would help. And scientists don't yet
understand how humans can survive the harsh radiation there.
International Space Station crews stay just six months in the
relative safety of low-Earth orbit, where radiation doses are high
but nothing like what people would get flying between here and Mars.
"Right now, this is a three-year round trip," Naderi said of a human
journey to Mars.
Although the rovers aren't focusing on aspects of Mars pertinent to
human survival there, "robotic missions like this help characterize
the environment," Crisp said. "What is the dust and soil made of?
Can you make better astronaut suits to protect the astronauts? Right
now we don't really know that."
Information about the soil can provide information about the
atmosphere, since they comprise a "coupled environment" like
Earth's, Naderi said.
The rovers are just one among several planned or discussed robotic
missions that would expand human knowledge of Mars, including one
that would return samples to Earth for analysis.
"All of those seem to be prudent preparation," Naderi said. "That's
what we did on the moon, sent the robots there before we sent the
humans."
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73 de Alan
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