NEW YORK - When humans finally set up residence on the moon,
our lives there will look very different.
Since many of the tried and true tools we use on Earth will
be impossible to carry along, some scientists are hard at work inventing from
scratch the machines we'll need to make life possible on the
moon.
One such example is building equipment.
"Bulldozers and excavation systems are pretty bulky and
heavy," said Kris
Zacny, director of drilling and excavation systems at Honeybee Robotics in
New York City. "We came out with a different method of digging that uses
gas."
Zacny's invention digs up ground by injecting gas into the
dirt, thereby creating a high-pressure situation from which the gas naturally
wants to escape. When it does fly upward, the gas' strong momentum ends up
taking dirt up with it.
Digging up the moon
In July 2008 Honeybee Robotics was awarded a contract to
develop tools that will help astronauts live and work on the moon as part of
NASA's Constellation program. Zacny has relied on the wisdom he gained working
in diamond, coal and gold mines in South Africa, as well as his doctorate
research on extraterrestrial excavation, to devise creative methods for digging
up the moon, including the gas-blowing digger. Working with their NASA
technical contacts, Rob Mueller and Greg Galloway, Zacny and his team hope to
create tools that will one day prove their usefulness on the moon.
In detail, this so-called pneumatic excavation mechanism
involves gas pumped into the ground through a thin tube encased by a wider
hose. When the gas escapes, carrying along material from the ground, it travels
up through the hose to a storage container.
"It's kind of like a vacuum cleaner, but the
reverse," Zacny said. Instead of using suction, the machine injects gas
down to draw material up.
The contraption weighs a lot less than conventional digging
tools, though it begs the question: Where will future moon-dwellers get the gas
needed to operate the machine?
One good source could be the carbon dioxide breathed out
every day by astronauts, he said. Another option is to burn any leftover fuel
in the rocket thrusters on the moon landing vehicle, and collect the exhaust.
"When a spacecraft lands on the moon, it has a little
extra fuel left over, just in case you have to fly longer than you
planned," Zacny said. "Once you land it's a deadweight."
But burning this fuel to create gas is great way to power
the pneumatic excavator, he said.
Reduce, reuse, recycle
Once the device has sucked up lunar dirt, or regolith, this
material could be conveniently
diverted and used as a protective covering over homes (regolith is good for
shielding from radiation). The dirt could also be processed to extract the
oxygen bound up in its minerals.
In order to free up the oxygen trapped inside, regolith must
be heated to high temperatures. Greg Mungas from Firestar Engineering, working
with Zacny, proposed passing the material through a heat exchanger after it is
extracted. Or, if the source of gas for the excavator is from leftover rocket
fuel, then the exhaust will already be hot, and as it passes into the regolith
it can heat the dirt up.
Since every bit of material that we carry to the moon adds
expensive weight to the spacecraft travelling there, engineers must design as
many thrifty ways as possible to get what they need from the moon and reuse
resources.
"You're going to be recycling quite a bit," Zacny
said. "It's like Lewis and Clark, living off the land."
For example, instead of carting up heavy water, astronauts
could travel with hydrogen, and then add oxygen later. Since oxygen is the
heavier ingredient in water, and it can be extracted from the surface, this
approach saves precious cargo weight.
And once a store of water has been created for the lunar
colony, most of it can be recycled without having to create more from scratch.
Lingering issues
Though engineers are well on their way toward preparing us
for life on the moon, some major issues have yet to be resolved.
"Something that we'll have to consider is
radiation," Zacny said. "We can close ourselves in habitats, but
radiation protection requires a
lot of shielding. We cannot solve this problem yet. Radiation can kill
us."
Moon dwellers will also have to contend with the ubiquitous
dust on the surface of the moon, which gets into everything and can wear down
joints and connectors and prevent sealing off doors. It also poses a health
risk to people, as it can cause breathing problems and is difficult to filter
out of habitats.
Other difficulties may lie in the astronauts themselves, as
opposed to the environment.
"You can have a lot of psychological issues,"
Zacny said. "On the International Space Station you can see Earth. If
there's an emergency, in an hour and a half you can come home and be in the
hospital. On the moon the Earth is farther away and you can feel
detached."
Why go to the moon?
While many scientists are busy planning humanity's future on
the moon, some people question whether we ought to be even trying to make it
back to a place we conquered in 1969.
But Zacny argues the pursuit is worthwhile, not just in
itself, but for the opportunity to invent new technologies and prepare for our
eventual quest to Mars. Plus, we can't help but want to try living on another
world besides Earth.
"We're going to explore. It's human nature," Zacny
said. "It's just a matter of time before we establish some kind of base on
the moon."
And when we do, Zacny would sign up in a heartbeat.
"I would go right now. I wouldn't even go back home
first," he said. "It's the adventure of a lifetime."
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