This answer, and I believe a few others, mention using water as a radiation shield. I looked around a bit, and did not find a good answer on the logistics of how you would do that. Ignoring the lift to space cost and assuming you have H2O in sufficient quantity near your space station, a number of problems remain.

How would you position it for shielding? Unless you place your water in a heated and pressurized container, the water won't remain in liquid state and will freeze solid.

Could I erect a temporary pressure tent on the outside of my habitat, position the water to let it freeze, and move on to the section behind the raw and exposed block of ice serving as my radiation shield? Would I need to cover the ice with something, to keep it from boiling off?

  • $\begingroup$ I guess the most reasonable approach would be a dual-walled balloon, with water between the walls; water pressure lower than air pressure inside. I have nothing to back that up though. $\endgroup$
    – SF.
    Commented Aug 19, 2013 at 11:04

1 Answer 1


If you leave ice exposed to vacuum then yes, it will sublime. The rate of sublimation will vary depending on whether it is in the dark or facing the sun, so you will probably want to have it in a plastic container to avoid it dissipating.

Of course, if you have enough then maybe the rate of sublimation won't be an issue for you, but if you have expended energy getting it there you might as well save it.


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