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February
14, 2007: NASA has been exploring space for nearly
half a century, often with stupendous success. Yet "there's
one thing we really don't know: what is the best
way to explore a planet?" declares Paul D. Spudis, a
senior planetary scientist at Johns Hopkins University’s Applied
Physics Laboratory in Laurel, Maryland.
Discovering
the most effective techniques for exploring a planet is itself
cutting-edge research—just as discovering the most effective
mining technologies or the best ways of surviving and making
machinery work in Antarctica are pioneering research.
 Thus,
for the same reasons that nations have founded university-level
schools of mines and the U.S. Army founded its own Cold Regions
Research and Engineering Laboratory, NASA wants to use the
Moon as a graduate school for exploration.
On
the Moon, astronauts can develop and test techniques for building
habitats, harvesting resources and operating machinery in
low gravity, high vacuum, harsh radiation, pervasive dust
and fantastic extremes of temperature—an environment whose
prolonged combination is simply impossible to duplicate on
Earth. What
they learn will be useful not only on the Moon, but also essential
for preparations in going to Mars.
Right:
Astronauts and robots work together on a lunar geology study,
an artist's concept. [Larger
image]
One
research project topping the curriculum: What is the best combination
of humans and robots? Unmanned orbiting spacecraft and rovers
have returned millions of gigabytes of high-quality data from
the Moon and planets, revolutionizing our understanding of the
solar system. But for geological field work, says Spudis, nothing
can replace a trained geologist with a rock hammer, experienced
eyes, and the knowledge to "understand rocks in the context
of their environment."
For
that reason, NASA wants to explore how best to blend humans
and machines. One promising technology is telepresence, similar
to what's now used in hospital operating rooms for certain
types of surgery. From the safety of a radiation-shielded
underground lunar habitat, a geologist's movements could be
"instantly mirrored by a robot on the surface, complete
with instant sensory feedback much as an astronaut has through
the gloves of a space suit," Spudis explains. Is that
the best way, though? In some circumstances, a robot on its
own making lightning-fast decisions with artificial intelligence
might do a better job. Again, it's a question best answered
by on-site research.
Above:
Human-robotic teleprescence, an artist's concept. Credit:
Pat Rawlings and NASA. [Larger
image]
Other
crucial things humans could learn from lunar experience is
how to "make useful things from dirt," Spudis says.
On the Moon and Mars, local resources are going to be crucial
to astronauts who cannot remain wholly dependent on Earth
for supplies. "Aside from solar power, we've never used
space resources for any mission," Spudis says, "so
we need to understand [how to do it]."
The
official NASA acronym for living off the land is ISRU, for
In-Situ Resource Utilization. ISRU is basically figuring out
how to dig into the surface of another planet, how to get
the alien dirt to funnel down a hopper in low gravity (a surprisingly
tricky problem), and how to crack and heat the soil to extract
valuable liquids and gases—all with high reliability and few
mechanical problems.
What's
in the lunar regolith that astronauts might need or want to
mine? Most immediately useful are oxygen and hydrogen. "From
those two elements, we can generate electricity using fuel
cells, which make drinkable water as a by-product," Spudis
explains. "Hydrogen and oxygen are also rocket propellant.
The oxygen astronauts can breathe."
 Good
news: Oxygen on the Moon is abundant. The lunar crust is 40
percent oxygen by mass, and NASA scientists have lots of ideas
for how to extract it. Simply heating lunar soil to very high
temperature causes gaseous oxygen to emerge. (For more information
on this, see Science@NASA's Breathing
Moonrocks.) The most efficient techniques remain to be
discovered.
Right:
Oxygen underfoot. 40% of the lunar surface, by mass, is oxygen.
Footprint and photo credit: Neil Armstrong, Apollo 11. [Larger
image]
Not-so-good
news: Hydrogen on the Moon is relatively rare. That's one
reason NASA is keen to explore the lunar poles where some
10 billion metric tons of frozen water may exist in permanently
shaded craters: "ice is a concentrated form of hydrogen,"
Spudis notes. Experience gained at the Moon's poles may apply
to Mars, where ice is also thought to be mixed with deep soil
and rock.
"We
need to set up shop on the Moon for one clear and understandable
reason," he concludes. "The Moon is a school for
exploration."
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Author: Trudy E. Bell
| Editor:
Dr. Tony Phillips | Credit: Science@NASA
|
