posted on Apr, 8 2013 @ 09:40 PM
Selective laser sintering is building of 3D physical objects from powder. It started with aluminum, where a thin layer of aluminum dust was swept over
the floor of a small chamber then sintered with a laser under computer control, then continued one thin layer at a time. It's one type of fast
prototyping. The technology has developed over the years, and it now it's done with various metals.
On the moon it could be done outdoors with moon dust to form an igloo of moon rock. You start with an airlock, then two robots take years to grow one
dome whose shell is a foot thick and whose diameter is 60 feet or more. Energy is provided, of course, by sunlight, and the only construction material
other than the airlock is the dust in the area, which should be cleared away, anyway, since it sticks to everything (individual particles have rough
surfaces, not smoothed by abrasion).
So it just takes some solar panels, two robots, an airlock, and lots of time. Whatever control by humans back on Earth the robots may need can be done
by volunteers. Some people would even pay for the chance to do that. Some would pay for the chance to spend an hour in a body suit that controls a
humanoid robot on the moon filling one sandbag with moon dust and placing it on a fence made of sandbags. The next customer could control another
robot to take video of the first as part of the deal. Each customer leaves with a DVD or whatever of the robot under his/her control doing some useful
task on the moon, plus video taken in Florida of the customer's training, putting on the control suit, etc.
When a LEM lands on the moon, moon dust spreads at high speed. In past missions there was nothing at the landing site. But if a lander sets down near
a base where there is equipment outdoors, that equipment, if close enough, will get sandblasted by that moon dust spread with great force by the retro
rocket. That has been confirmed with simulations conducted by NASA. Takeoff doesn't create that problem with landers like a LEM, because the stage
used for landing is left behind, and the stage used for return is above that (plus the dust was cleared away by the retro rocket when landing).
Anyway, a base where rockets will be coming and going should be cleared of moon dust, and robots building a dome will use up all the dust nearby.
If the dome is to be only used to protect equipment from direct sunlight and asteroid strikes, it won't need an airlock, in which case an aluminum
doorframe with rounded corners will do. And, like moon rock, the dome and its floor will be somewhat radioactive unless covered on the inside with
Apollo missions were expensive because humans were in a hurry to get to the moon once leaving LEO and had to come back. Dome-building robots have no
such requirements. It's a one-way trip, and they don't mind taking many months to get there, not requiring life support. All that translates into a
lot less fuel and hardware.
Then, once humans want to have frequent moon shuttles in operation, there is a type of fuel that can be produced in space using sunlight and adds
virtually no mass to a spacecraft: positrons (antielectrons). This fuel can be made by collecting sunlight with large sausage-shaped mylar balloons,
each transparent on one side and mirrored on the opposite interior face, allowing sunlight entering a balloon to be reflected and focused on a central
collector to produce electricity for a powerful laser to zap 1-mm gold plate, creating a shower of positrons to be captured and stored in a magnetic
bottle. It's all automated. A moon shuttle stops by the orbiting positron farm and exchanges an empty bottle for a partially full one, which, in
together with propellant (which could merely be a teflon rod), provides enough fuel for a round trip to lunar orbit, leaving landing and return to
lunar orbit to chemical rockets, because any kind of antimatter rocket emits gamma rays and should only be used where won't cause damage.