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May
22, 2006: Long before David Beaty became associate
Chief Scientist for NASA's Mars Program, he was a prospector.
Beaty spent 10 years surveying remote parts of Earth for precious
metals and another 12 years hunting for oil.
And
this qualifies him to work for NASA? Precisely.
Beaty
has the kind of experience NASA needs as the agency prepares
to implement the Vision for Space Exploration. "Mining
and prospecting are going to be key skills for settlers on
the Moon and Mars," he explains. "We can send them
air and water and fuel from Earth, but eventually, they'll
have to learn to live off the land, using local resources
to meet their needs."
Above:
Lunar mining, an artist's concept.
On
the Moon, for instance, mission planners hope to find water
frozen in the dark recesses of polar craters. Water can be
split into hydrogen for rocket fuel and oxygen for breathing.
Water is also good for drinking and as a bonus it is one of
the best known radiation shields. "In many ways,"
notes Beaty, "water is key to a sustained human presence."
Ice mining on the Moon could become a big industry.
Beaty
has learned a lot from his long career prospecting, exploring
and mining on Earth. Now, with an eye on other worlds, he
has distilled four pieces of wisdom he calls "Dave's
Postulates" for prospectors working anywhere in the solar
system:
Postulate
#1: "Wishful thinking is no substitute for scientific
evidence."
"On
Earth, banks won't lend money for less than proven reserves.
From a bank's viewpoint, anything less than proven is not
really there. This lesson has been learned the hard way by
many a prospector," he laughs.
For
NASA the stakes are higher than profit. The lives of astronauts
could hang in the balance. "Proven reserves on the Moon
can perhaps be thought of as having enough confidence to risk
the lives of astronauts to go after it."
What
does it take to "prove" a reserve—that is, to know
with confidence that a resource exists in high enough concentration
to be produced?
"That
depends on the nature of the deposit," explains Beaty.
"Searching for oil on Earth, you can drill one hole,
measure the pressure and calculate how much oil is there.
You know that oil probably exists 100 feet away because liquids
flow. However, for gold you must drill holes 100 feet apart,
and assay the concentration of gold every five feet down each
hole. That's because the solid earth is heterogenous. 100
feet away the rocks may be completely different."
Deposits
on the Moon aren't so well understood. Is lunar ice widespread
or patchy, deep or shallow? Does it even exist? "We don't
know," says Beaty. "We still have a lot to learn."
Postulate
#2: "You cannot define a reserve without specifying
how it can be extracted. If it can't be mined, it's of no
use." Enough said.
 Postulate
#3: "Perfect knowledge is not possible. Exploration
costs money, and we can't afford to buy all the information
we want. We have to make choices, deciding what information
is critical and what's not."
Right:
Robotic ice miner, an artist's concept. Credit: NASA/John
Frassanito & Associates.
He
offers the following hypothetical example:
"Suppose
we decide to send a robot with a little drill and an onboard
laboratory into Shackleton Crater, a place on the Moon with
suspected ice deposits. We're going to have to think pretty
carefully about that lab. Maybe it can contain only two instruments.
What are the two things we most need to know?"
"Suppose
further that someone on Earth has invented a machine that
can extract water from lunar soil. But it only works if the
ice is close to the surface and if the ice is not too salty."
The choice is made. "We'd better equip the robot with
instruments to measure the saltiness of the ice and its depth
in the drill hole."
Finally,
Postulate #4: "Don't underestimate the
potential effects of heterogeneity. All parts of the Moon
are not alike, just as all parts of Earth are not alike. So
where you land matters."
Ultimately,
says Beaty, if geologists and engineers work together applying
these rules as they go, living off the land on alien worlds
might not be so hard after all.
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Authors: Trudy E. Bell
and Dr. Tony Phillips
| Production Editor:
Dr. Tony Phillips | Credit: Science@NASA
|
