Dear Friends,
It seems to me, a possible solution to the problem of habitats on Mars, is the potential of expanded polymer housing. Instead of building a base by 3D printing, grow a structure using expanding polymers. A huge construction could be shipped as a liquid, dropped on the planet, and once in contact with the low air pressure, it would expand into a large multi celled space. Like a loaf of bread. It matters not what the gas is in those spaces, they’ll be evacuated once the cell is cut into. Each cell could be a room. If the cell size and orientation could be controlled, so much more efficient the system. Perhaps a way to create them on Mars with a perchlorate based reaction could be possible down the road? Nevertheless, a foam house would be extremely efficient for the first generation anyway.
It would be important to have a foam that expands to have cells that are at least ten by ten feet in diameter and larger would be better. The low air density should facilitate the process. Each cell would be a room. The whole thing would look like a gigantic drop of triple expanding polyurethane foam, you dropped on the patio, while sealing your foundation. Once expanded the foam homes would be cut into. Airlocks installed and air handling equipment set up. Then, once ready, it could be covered with dirt. The urethane would be easy to work with… machinable, lightweight and durable. As is always the case in real estate, location would be important. The base of crater walls might be a good location to add extra protection from meteors. They would also cut the cosmic ray load by half. I’ve always favored the Valles Marineris or Hellas basin for Mars base locations.
One advantage is that most expanding polyurethane based products have lots of hydrogen atoms in them. Those hydrogen atoms are great at slowing incoming cosmic rays… especially neutrons. Combined with dirt to stop solar radiation and the sievert levels inside could be Earth like. Moreover, urethane can be made airtight with a little paint. Especially if polyurea spray was used on the inside. That very strong coating would make the inside extremely durable. It could be applied in seconds and is self hardening. As long as it doesn’t react with the foam it would be the perfect inside coating. It would also work for the outside as well. Application of an epoxy spray can’t be as difficult as using a giant 3D printer… on Mars.
The arced space under the floors could be used as storage or space to run infrastructure, small cells for closets and large cells for meeting spaces. A one ton glop of triple expanding polyurethane released on the surface of Mars might make the perfect habitat. Simple, light weight, easy to work with, and with radiation shielding as a side benefit. Heck, it could be tried on the Moon. If it works there, and the technology is perfected, dozens of habitats could be grown before people even go to Mars. Ready to have the airlocks installed, the walls sprayed, and infrastructure run, the moment the crew gets there. The whole thing would have a Space 1999, UFO or 2001 feel to it, with the arced walls and probably white paint. Perhaps, women on the Moonbase could wear purple wigs, and men Nehru jackets?
It would be an interesting experiment. Try expanding a glop of polyurethane in a Mars density atmosphere simulation. Play with the compound to get the cells to be room sized. Then send a prototype to the Moon or Mars. The whole try would be exponentially cheaper than launching a single house sized 3D printer into space. Less “cool” to be sure, and not really a high tech solution either, but it has the benefit of being cheap, simple and doable. Such technology would be a game changer in the colonization of other worlds. Even Venus, if they could be light enough to float at the proper level. Polyurethane being acid resistant and all. A poly-dirigable floating in Venus’ atmosphere. Think about it.
Sincerely,
John Pepin
