ACHIEVING EARTH INDEPENDENCE
- how an off-Earth base could quickly become self-sufficient -

Producing Habitats Art Harman describes how local resources could be utilized to construct habitats for a growing colony over a 20-year population doubling time.

INITIAL, INFLATABLE HABITATS
There is lots of hype about 3-D printing of habitats on the Moon or Mars. But inflatables are a far faster and safer approach initially. Inflatables can be very large in volume yet pack into a relatively small area. Inflatables on the Moon would not need the most massive layer which is the micrometeorite / orbital debris (MMOD) layer because telerobots could cover the inflatables with local dirt.

From outside to inside, the layers of an inflatable habitat and their masses are as follows:

• (0.6 kg/m2) Outer abrasion-resistant layer
  
• (1.0 kg/m2) Pressure-restraint layer (e.g. Kevlar)
  
• (0.5 kg/m2) Air-proof layer #1
  
• (0.5 kg/m2) Air-proof layer #2
  
• (0.6 kg/m2) Inner abrasion-resistant layer
  

STOCKPILED HABITATS
Give the great simplicity of inflatables for creating habitable areas, a prepper colony would probably not initially produce its own habitats but we would simply ship several such habitats. The colony could keep those habits in storage and then deploy them when needed and after they had locally produced the internal hardware from local resources. But, eventually the stockpiles of inflatable habitats would run out and if the colony were to grow, they would need to produce their own habitat structures from local materials.

PRODUCING HABITATS
Locally-produced habitats would probably be made out of metals and would be pressure vessels like space stations. The lunar highlands contain unoxidized nickel-iron at 1% concentration. This could be magnetically separated and melted using solar heating. Locally-produced equipment could convert the melted metal into sheet metal with enough thickness to ensure it would hold up to the considerable difference in pressure from the inside to the outside. A welding process (such as stir friction welding) would also need to be implemented to weld the sheets together to form habitable spaces. External air locks would need to be similarly produced and welded on. After telerobots cover the new habitat with dirt to shield against space radiation, the habitat could be pressurized using locally-produced air and crew could enter and emplace life-support and other equipment.

Given that stockpiled inflatables could last a colony for a number of years and metal habitats would only have to be produced at the rate that the population grows, the process of producing new, metal habitats could be relatively slow and within the time availability of a relatively small crew.

Click here to see what the locally-produced habitat called the SquareHab would look like.