Spacesuit Requirements

a. A space suit must perform several functions to allow its occupant to work safely and comfortably. It must provide:
A stable internal pressure. This can be less than earth's atmosphere, as there is usually no need for the spacesuit to carry nitrogen. Lower pressure allows for greater mobility, but introduces the requirement of pre-breathing to avoid decompression sickness.

b. Mobility. Movement is typically opposed by the pressure of the suit; mobility is achieved by careful joint design. See the Theories of spacesuit design section.

c. Breathable oxygen. Circulation of cooled and purified oxygen is controlled by the Primary Life Support System.

d. Temperature regulation. Unlike on Earth, where heat can be transferred by convection to the atmosphere, in space heat can only be lost by thermal radiation or by conduction to objects in physical contact with the space suit. Since the temperature on the outside of the suit varies greatly between sunlight and shadow, the suit is heavily insulated, and the temperature inside the suit is regulated by a Liquid Cooling Garment in contact with the astronaut's skin, as well as air temperature maintained by the Primary Life Support System.

e. Shielding against ultraviolet radiation
f. Limited shielding against particle radiation
g. Protection against small micrometeoroids, provided by a Thermal Micrometeoroid Garment, which is the outermost layer of the suit

h. A communication system
i. Means to recharge and discharge gases and liquids
j. Means to maneuver, dock, release, and/or tether onto spacecraft
k. Means of collecting and containing solid and liquid waste (such as a Maximum Absorbency Garment)

American Model Spacesuit

Extravehicular Mobility Unit used on both the Space Shuttle and International Space Station. The EMU is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for a Shuttle or ISS crew member to perform extra-vehicular activity (EVA) in earth orbit.






Advance Crew Escape System Pressure Suit used on the Space Shuttle. The Advanced Crew Escape Suit or ACES suit, is a full pressure suit currently worn by all Space Shuttle crews for the ascent and entry portions of flight. The suit is a direct descendant of the U.S. Air Force high-altitude pressure suits worn by SR-71 Blackbird and U-2 spy plane pilots, X-15 and Gemini pilot-astronauts, and the Launch-Entry Suits worn by NASA astronauts starting on the STS-26 flight, the first flight after the Challenger Disaster

Apollo/Skylab A7L EVA and moon suits. The A7L Apollo & Skylab spacesuit is the primary pressure suit worn by NASA astronauts forProject Apollo, the three manned Skylab flights, and the Apollo-Soyuz Test Project between 1968 and the termination of the Apollo program in 1975







Manned Orbiting Laboratory MH-7 space suits










Gemini spacewalk suits, used for Project Gemini











Navy Mark V high-altitude/vacuum suit used for Project Mercury