Talk-Polywell.org

Brainstorming here ...
Sintered Martian soil for a structural shell, more soil heaped over the top for radiation shielding and to counter internal pressure, a coating of some kind applied inside to seal cracks and pores left by the sintering process.

My thoughts were sintered blocks over an inflated habitat. Bigalow type habitats would be small and easy to ship, I wasn't going to bother making that on site.

Personally, I think the whole notion of printing such large volumes misses the point of the real benefits to be had with additive manufacturing. NASA needs to stop treating 3D printing as a fad and think more seriously. Especially when you look at what an energy intense process sintering of any kind is, one really wants to look at filament winding, and injection molding way before sintering. If you want to sinter an entire city, you need to look at installing GW's of power just for manufacturing, and that makes no sense. Even given robot manufacturing well in advance of people on Mars, one should favor low energy construction methods.

Especially note there is no real benefit to be had sintering iron rich soil when you can just put up an inflatable and use a bulldozer to cover it with unpacked soil. No reason to sinter at all.

I hate to say this, but it's such a BAD idea it makes one wonder whether it is born of an interest to justify huge fission power generation on planet. I mean really, why would anyone chose precisely the WRONG criteria for habitat construction? I have a hard time believing the NASA engineers are all this stupid.

Why not make bricks in a little oven that recycles the water used? Much less energy intensive, and robots could easily handle bricks.

Could do a double shell dome structure around an inflatable bag - one wythe of brick each side of the bag - then replace the air in the bag with water for radiation shielding.

Would still need an interior coating or covering for pressurization.

Edited to add: They could just as well be 3D printed bricks, if that's a requirement of the criteria. Just stick the printer/curing area in a container that can reclaim the water out of the bricks during the curing process. http://www.3ders.org/articles/20121101- ... ction.html

Could make bricks by pressing material into a mold and baking to solidify, no water needed. Water is useful, but not strictly needed, for shaping clay and getting it to hold shape until baked.

My plans were mostly for the moon, and solar(especially thermal solar) is plentiful on the moon at least half the time. Just focus the sunlight down enough, and you can slag anything. While a brick mold would probably be faster and easier, a solar thermal sintering machine would give you more flexibility. I was thinking you'd be making larger blocks for retaining walls, paving stones, etc. with the machine too.

Other thing is you do need structure. The two or three meters of lunar or Martian soil you need for radiation shielding may not weigh as much as on earth, but it will still have weight, so you can't just throw loose dirt on top of an inflatable I don't think. It would be good to have the options.