Some discussion around the existing question What is the largest naturally occurring body that could be hollowed and safely lived in? has lead me to post this question. I think the solution revolves around the strength of water ice in a vacuum, but I may be mistaken.

Assuming 100% pure water ice is used to create a hollow structure could it be pressurized to support human life suitable for a space station or transportation device (spaceship)? If yes, what is the largest structure that could be safely constructed?

There are of course many variables

  • The structure is 100% pure ice, insulating materials inside the structure are anchored to the sphere/structure without providing structural integrity
  • A naturally existing body may be hollowed
  • A structure may be created from pure water
  • A sphere is imagined but not required
  • At least half the radius of the structure must be hollow (no building caves on Europa)
  • Sublimation may be addressed without providing structural integrity
  • Spin to create gravity is desirable but not required
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    $\begingroup$ The hard sci-fi book "The Next Continent" wrote about lunar igloos near the moon's south pole. They argued it with physical principles and referenced some NASA architectures that used a similar method. Adhesion between blocks of ice was achieved by spraying water which then froze. I think that answers to the title of this question, but the full question may have broadened a little bit too much... $\endgroup$
    – AlanSE
    Mar 6 '15 at 20:08
  • $\begingroup$ I was trying to keep the title simple, do you think it needs to be edited to more closely match the body of the question? $\endgroup$ Mar 6 '15 at 20:19
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    $\begingroup$ Not sure what you mean by "Sublimation may be addressed without providing structural integrity" At 90k, ice in a vacuum starts sublimating at a good rate. I suppose with ice you could have a nice reflective surface, say a 90% albedo. To get a 90 k black body temp, 3 A.U. is sufficient. However the humans within would generate heat. $\endgroup$
    – HopDavid
    Mar 6 '15 at 23:07
  • $\begingroup$ Are we assuming the inside to be directly connected to the outside, or would it be pressurized and/heated? $\endgroup$ Mar 7 '15 at 14:06
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    $\begingroup$ My first glance Googling seems to indicate ice is a crumby material so far as tensile strength goes. But most ice balls aren't pure ices. There's often some metal, alumina, silica as well carbon and nitrogen compounds. There's science fiction where people just hollow out an asteroid and -- Voila! -- A living space! I don't think that's plausible. But building a hab from asteroidal materials is doable (in my opinion). Metals and materials for a supporting structure would need to be extracted and then the beams, mesh, etc., manufactured $\endgroup$
    – HopDavid
    Mar 10 '15 at 17:13

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