Crys may have a different view of the size than I do, so I'll leave that answer up to her.<br/><br/>Mentally, I see the shelters as having to be:<br/><br/>1. man-portable, or at least storable on a small vehicle as part of an emergency survival kit<br/>2. self contained, it's own oxygen supply and power unit<br/>3. self deploying<br/><br/>These requirements means that it would be small, probably no more than 4 or 5 feet tall and probably not much more than 6 feet in diameter.<br/><br/>This should sleep 2 relatively comfortably and 3 in a pinch (4 if you're really friendly) It may not make any sense, but the more people, the more air used by person.It has to do with the CO2 scrubbers and higher demands on the pressure. 3 people actually breath and exhale more than 1 person x3.<br/><br/>I know that "man-portable" in the lower gravity means that you can carry more individually, but it's the space issue that dictates an emergency shelter. On the other hand, the colony probably has "several" larger shelters for this kind of expedition, and those aren't quite so size restrictive and might sleep more. So, in the end, it's up to Chrys.