Space suits provide a livable and portable environment for the occupant. This includes:
- A supply of air and water
- A mechanism to get rid of excess heat
- A propulsion system
Space is not cold as many people imaging so freezing is not usually a problem. Getting rid of heat is the major issue. A vacuum is an almost perfect insulator so heat cannot be removed by convection only by radiation. The heat affecting a spacesuit comes from the occupants metabolism, equipment, and from sunlight.