High Quality Content by WIKIPEDIA articles! A space activity suit (SAS) or mechanical counterpressure suit is an experimental spacesuit which applies stable pressure against the skin by means of skintight elastic garments. The SAS is not inflated like a conventional spacesuit: it uses mechanical pressure, rather than air pressure, to compress the human body in low-pressure environments. Development was begun by NASA and Paul Webb in the late 1960s but was discontinued in the early 1970s. Pressurized suits are still currently used. Research is under way at the Massachusetts Institute of Technology (MIT) on a "Bio-Suit" System which is based on the original SAS concept.