So the prerequisites for this question are, of course, strength vs mass. The lighter, the better, in all circumstances, however it still needs to be strong enough to have people inside it and to hold atmosphere.

Aluminium seems like the default choice, but I was wondering if there were better alternatives. Aluminium would obviously be the -cheapest- solution, but I'm assuming money being no object for this.

Titanium was my next thought, but I'm not sure you gain a huge amount vs aluminium.

Then I started thinking about carbon fibre and kevlar-type products, but it's been very difficult to find information about the structural uses for carbon-based materials. It seems to be stronger, but also more brittle, and having things bend (aluminium) would seem to be better than having it shatter? Also carbon fibre seem to have issues with both heat and cold, neither of which is good for space it would seem?

Not sure if there are any other composite option out there. I've gone through the somewhat related threads on here but none seem to go along these lines, so thought I'd ask the question :)

  • $\begingroup$ Is this for a ship which will never undergo thrust (acceleration from local engines), or for a ship which is intended to move from place to place in zero-g environments? It makes a big difference. Not to mention that choosing materials which can block radiation is important as well. $\endgroup$ Nov 12, 2019 at 14:11
  • $\begingroup$ This is for a ship that will undergo thrust, but only on a relatively small scale. It won't ever be subjected to the high G's of liftoff, it'll be built in orbit to travel between orbits. Ion engines. Continuous low thrust. It is designed with a spinning section for habitation, which will be under a constant 1Gish of force, but again I wouldn't say that qualifies as heavy thrust. Radiation is a concern. However it seems that the choice is to either go with 7+meters of water or regolith, or no shielding at all, and you end up with the same risks either way. $\endgroup$
    – nirurin
    Nov 12, 2019 at 22:25
  • $\begingroup$ Perform a "Trade Study". Choose criteria (mass, radiative shielding, cost, etc), rank the criteria for importance, and put in each of the materials values. Normalize and multiply by the criteria rank, sum to get the rankings of overall performance for your criteria. Choose the best performing material with objective evidence to support your choice. $\endgroup$
    – mothman
    Nov 13, 2019 at 1:22

1 Answer 1


Your question is underspecified, but you might find something like TransHab (or other inflatable spacecraft designs) to fit the bill. There's already one such module attached to the ISS, so the principle appears to be entirely sound and practical.


From this older NASA page on TransHab, you can see that the membranes are made from layers of nextel ceramic fabrics, open cell foam, kevlar, nomex and something called combitherm (which may or may not be what this site is about).

You'd still probably want to use something like aluminium for the skeleton, of course, but there isn't necessarily any need for a solid metal outer of any kind.


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