"Have Spacesuit, Will Travel"
— Robert Heinlein book title.
A space suit is a suit of protective clothing designed to protect the wearer from the environment of space. It's most obvious function is contain the air an astronaut needs to breathe; but it also maintains the body's pressure against the vacuum of space, protects against temperature extremes, and other vital life support functions.
Although space-tailoring is still in its infancy, we can probably expect a variety of different kinds of suit to develop.
Amongst these, we're likely to see some kind of suit designed for prolonged work in microgravity and hard vacuum - what NASA currently calls an EVA1 Suit - used for messing about on the ship's hull, exploring airless space debris and the like. This sort of suit may also be used for un-docked ship to ship transfers.
Related to these suits there will probably be something quite a bit heavier, used for work with a significant risk of debris and suit damage such as asteroid mining and this sort of suit is likely to be at least related to whatever the military use.
We can also expect some kind of survival suit, designed to be used in emergencies and probably prioritising ease of use and life support over clever features.
In some settings, whatever ships crew normally wear may be vacuum resistant in an emergency, possibly with a pull out bags to protect the head and hands, giving the wearer some defence even if they suffocate quite quickly.
Realistically, there is likely to be a divide between suits meant to be worn "indoors" (even when indoors is depressurised) and "outdoors" - and this is likely to revolve around shielding from debris and incident radiation (thermal, electromagnetic and atomic alike). Those suits designed to be used on the surface of a planet are likely to be different again.
[This article is a stub. Feel free to expand on it.]
Game and Story Use
- If your campaign takes place in space, you gotta have a spacesuit. Even if it's just a goldfish bowl bubble-helmet. It's a rule.
- Verisimilitude will probably require some competing brands, and general characterisation of the suits - spacefarers are likely to take a great deal of interest in these things.
- Suit training is likely to be a specific skill set in any set of rules that doesn't assume ubiquitous proficiency with them.