Fun! Not sure on rules, but maybe have terrain rule that you wound after each round (ala Lava Field) and reduced movement (ala Heavy Snow); but related equipment glyph of gas mask/rocket pack (ala Star-Lord's helmet/armor) that ignores these rules and that everyone starts out with in most scenarios, but can be stolen/dropped/handed-off as per normal equipment glyph rules. I am sure Super-strength can also be worked in to mitigate damage/hindrance of Cosmic Space.
Range/sighting is probably the most difficult rule to work out. I think even though move can be restricted in Cosmic Space, maybe range should be increased to compensate as arrows and bullets go infinite distance in space. Maybe rules are to half your move (rounded down) but double your normal range if more than 1. Melee units will be hampered with this however.
Anyway looking forward to this. I would also say that maybe the
MtG:AotP Innistrad mats can be an alternative to this as they are easier to obtain for a lot of people.