FYI,

"How to Build Lunar Homes From Moon Dirt"
Staff Writer
http://news.yahoo.com/s/space/20080903/sc_space/howtobuildlunarhomesfr
ommoondirt

: 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.

: 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. The engineers propose 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."

Mark Reiff