An 'Exosuit' is a suit that allows survival in exotic environments - like other planets with no breathable air. This is not to be confused with '0-g' armors that allow space boarding actions and absolutely need some means of propulsion.
Any armor that is described as 'is Exosuit' is viable in these extreme enviros. Developing an Exosuit is a serious challenge - starting with Hands' understandable fear of man-machine fusion, and ending with a plethora of systems that allow comfortable survival in such a small, sealed vessel.