The Mark III or MK III (H-1) is a NASA space suit technology demonstrator built by ILC Dover. While heavier than other suits (at 59 kilograms (130 lb), with a 15 kilograms (33 lb) Primary Life Support System backpack), the Mark III is more mobile, and is designed for a relatively high operating pressure. [1]
The Mark III is a rear-entry suit, unlike the EMU currently in use, which is a waist-entry suit. The suit incorporates a mix of hard and soft suit components, including hard upper torso, hard lower torso and hip elements made of graphite/epoxy composite, bearings at the shoulder, upper arm, hip, waist, and ankle, and soft fabric joints at the elbow, knee, and ankle.
The Mark III was originally designed to an 8.3 pounds per square inch (57 kPa) operating pressure, which would make the Mark III a "zero-prebreathe" suit. For a vehicle with a one atmosphere, mixed-gas environment, such as that on the International Space Station, the suit could be donned and ready for an EVA within the normal donning and checkout period without risk of the bends, which can occur with rapid depressurization from an atmosphere containing nitrogen or another inert gas. Currently, ISS astronauts must spend several hours in a reduced pressure, pure oxygen environment before EVA to avoid these risks. [1]
The Mark III, as well as ILC's I-Suit, has been involved in field testing during NASA's annual Desert Research and Technology Studies (D-RATS) field trials, during which suit occupants interact with one another, and with rovers and other equipment. [2]
Subjects wearing the Mark III were able to kneel to pick up objects, a task which would be difficult in either the Apollo A7L or Shuttle EMU suit. Dean Eppler, a geologist at NASA's Johnson Space Center who wore the suit during testing, commented that "the Mark III in many cases has almost shirtsleeve-equivalent mobility." [3] Eppler has spent more than 100 hours in the Mark III. [2]
As a result of the success of zero- and partial-gravity testing on the KC-135 Vomit Comet and in 1g field tests in Arizona and at Johnson Space Center, the EVA Project Office at Johnson Space Center is currently looking toward a soft suit design for future astronauts that incorporates the enhanced mobility features of the Mark III, but with a lower weight penalty.[ citation needed ] This new pressure garment design will provide greater surface mobility for planetary surface exploration than was available with the Apollo Program A7L and A7LB pressure garments.
A space suit or spacesuit is a garment worn to keep a human alive in the harsh environment of outer space, vacuum and temperature extremes. Space suits are often worn inside spacecraft as a safety precaution in case of loss of cabin pressure, and are necessary for extravehicular activity (EVA), work done outside spacecraft. Space suits have been worn for such work in Earth orbit, on the surface of the Moon, and en route back to Earth from the Moon. Modern space suits augment the basic pressure garment with a complex system of equipment and environmental systems designed to keep the wearer comfortable, and to minimize the effort required to bend the limbs, resisting a soft pressure garment's natural tendency to stiffen against the vacuum. A self-contained oxygen supply and environmental control system is frequently employed to allow complete freedom of movement, independent of the spacecraft.

A mechanical counterpressure (MCP) suit, partial pressure suit, direct compression suit, or space activity suit (SAS) 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 the Air Force in the late 1950s and then again in the late 1960s, but neither design was 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.
The Extravehicular Mobility Unit (EMU) is an independent anthropomorphic spacesuit that provides environmental protection, mobility, life support, and communications for astronauts performing extravehicular activity (EVA) in Earth orbit. Introduced in 1981, it is a two-piece semi-rigid suit, and is currently one of two types of EVA spacesuits used by crew members on the International Space Station (ISS), the other being the Russian Orlan space suit. It was used by NASA's Space Shuttle astronauts prior to the end of the Shuttle program in 2011.
The Quest Joint Airlock, previously known as the Joint Airlock Module, is the primary airlock for the International Space Station. Quest was designed to host spacewalks with both Extravehicular Mobility Unit (EMU) spacesuits and Orlan space suits. The airlock was launched on STS-104 on July 14, 2001.
ILC Dover, LP is a special engineering development and manufacturing company, globally headquartered in Frederica, Delaware. ILC Dover specializes in the use of high-performance flexible materials, serving the aerospace, personal protection, and pharmaceutical industries.
The Apollo/Skylab space suit is a class of space suits used in Apollo and Skylab missions. The names for both the Apollo and Skylab space suits were Extravehicular Mobility Unit (EMU). The Apollo EMUs consisted of a Pressure Suit Assembly (PSA) aka "suit" and a Portable Life Support System (PLSS) that was more commonly called the "backpack". The A7L was the PSA model used on the Apollo 7 through 14 missions.
The Mercury space suit was a full-body, high-altitude pressure suit originally developed by the B.F. Goodrich Company and the U.S. Navy for pilots of high-altitude fighter aircraft. It is best known for its role as the spacesuit worn by the astronauts of the Project Mercury spaceflights.

The Gemini spacesuit is a spacesuit worn by American astronauts for launch, in-flight activities and landing. It was designed by NASA based on the X-15 high-altitude pressure suit. All Gemini spacesuits were developed and manufactured by the David Clark Company in Worcester, Massachusetts.
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The I-Suit is a spacesuit model constructed by ILC Dover. The suit began as an EVA mobility demonstrator, developed to meet a contract awarded by NASA to ILC in 1997 for an all-soft suit.
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The Krechet-94 is a space suit model developed for lunar excursion during the Soviet crewed lunar program. It was designed by NPP Zvezda. Development began in 1967, concurrently with the Orlan suit for microgravity spacewalks. The developmental model was known simply as Krechet.
The Neutral Buoyancy Simulator was a neutral buoyancy pool located at NASA's George C. Marshall Space Flight Center (MSFC). Engineers and astronauts developed hardware and practiced procedures in this tank from its completion in 1968 through its decommissioning in 1997. Marshall recognized the need for underwater simulations of extra-vehicular activities (EVAs) and developed three successively larger tanks for the purpose. The Neutral Buoyancy Simulator contributed significantly to the American crewed space program. Skylab, the Space Shuttle, Hubble Space Telescope, and the International Space Station have all benefited from the Neutral Buoyancy Simulator. Until Johnson Space Center constructed the Weightless Environment Test Facility in the mid-1970s, MSFC had the only NASA-owned test facility that allowed engineers and astronauts to become familiar with the dynamics of body motion under weightless conditions.
The Constellation Space Suit was a planned full pressure suit system that would have served as an intra-vehicular activity (IVA) and extra-vehicular activity (EVA) garment for the proposed Project Constellation flights. The design of the suit was announced by NASA on June 11, 2008, and it was to be manufactured by Houston, Texas-based Oceaneering International, the 4th company after the David Clark Company, Hamilton Sundstrand, and ILC Dover to produce life-support hardware, as a prime contractor, for in-flight space use.
The Z series is a series of prototype extra-vehicular activity (EVA) space suits being developed in the Advanced Extravehicular Mobility Unit (AEMU) project under NASA's Advanced Exploration Systems (AES) program. The suits are being designed to be used for both micro-gravity and planetary EVAs.
A neutral buoyancy pool or neutral buoyancy tank is a pool of water in which neutral buoyancy is used to train astronauts for extravehicular activity and the development of procedures. These pools began to be used in the 1960s and were initially just recreational swimming pools; dedicated facilities would later be built.
A single-person spacecraft is a vehicle designed for space travel. The concept has been used in science fiction and actual ships such as the Mercury capsule, Vostok and some suborbital designs. Single-person spacecraft have been envisioned as a supplement or replacement for space suits in certain applications. The Von Braun Bottle suit of the 1950s functions as a hybrid of a space suit and a one-person spacecraft.
A Mars suit or Mars space suit is a space suit for EVAs on the planet Mars. Compared to a suit designed for space-walking in the near vacuum of low Earth orbit, Mars suits have a greater focus on actual walking and a need for abrasion resistance. Mars' surface gravity is 37.8% of Earth's, approximately 2.3 times that of the Moon, so weight is a significant concern, but there are fewer thermal demands compared to open space. At the surface the suits would contend with the atmosphere of Mars, which has a pressure of about 0.6 to 1 kilopascal. On the surface, radiation exposure is a concern, especially solar flare events, which can dramatically increase the amount of radiation over a short time.