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Space suit

2007 Schools Wikipedia Selection. Related subjects: Space transport

          "Space Suit" is also an instrumental track from They Might Be
          Giants' 1992 album Apollo 18.

   Space suit from Apollo moonwalk
   Enlarge
   Space suit from Apollo moonwalk

   A space suit is a complex system of garments, equipment and
   environmental systems designed to keep a person alive and comfortable
   in the harsh environment of outer space. This applies to
   extra-vehicular activity outside spacecraft orbiting Earth and has
   applied to walking, and riding the Lunar Rover, on the Moon.

   Some of these requirements also apply to pressure suits worn for other
   specialized tasks, such as high-altitude reconnaissance flight. Above
   Armstrong's Line (~63,000ft.), pressurized suits are needed in the
   sparse atmosphere. Hazmat suits that resemble space suits are also used
   when dealing with certain types of biological hazards.

Spacesuit requirements

   Several things are needed for the spacesuit to function properly in
   space. 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.
     * breathable oxygen. Circulation of cooled and purified oxygen is
       controlled by the Primary Life Support System.
     * temperature regulation. Heat can only be lost in space by thermal
       radiation, or conduction with objects in physical contact with the
       space suit. Since heat is lost very slowly by radiation,
       temperature is regulated by a Liquid Cooling Garment and heavy
       insulation on the hands and possibly feet.
     * electromagnetic radiation shielding
     * particle radiation shielding
     * micrometeoroid protection
     * mobility
     * a communication system
     * means to recharge and discharge gases and liquids
     * means to maneuver, dock, release, and tether on space craft

Theories of Spacesuit Design

   A space suit should allow its user natural and unencumbered movement.
   Nearly all designs try to maintain a constant volume no matter what
   movements the wearer makes. This is because mechanical work is needed
   to change the volume of a constant pressure system. If moving an arm or
   hand causes a change in the volume of the space suit, then the
   astronaut has to do extra work every time he bends that joint, and he
   has to maintain a force to keep the joint bent. Even if this force is
   very small, it can be seriously fatiguing to constantly fight against
   your suit. It also makes delicate movements very difficult.

   All space suit designs try to minimize or eliminate this problem. The
   most common solution is to form the suit out of multiple layers. The
   bladder layer is a rubbery, airtight layer much like a balloon. The
   restraint layer goes outside the bladder, and provides a specific shape
   for the suit. Since the bladder layer is larger than the restraint
   layer, the restraint takes all of the stresses caused by the pressure
   of the suit. Since the bladder is not under pressure, it will not "pop"
   like a balloon, even if punctured. The restraint layer is shaped in
   such a way that bending a joint will cause pockets of fabric, called
   gores, to open up on the outside of the joint. This makes up for the
   volume lost on the inside of the joint, and keeps the suit at a
   constant volume. However, once the gores are opened all the way, the
   joint cannot be bent anymore without a considerable amount of work.

   In some Russian spacesuits strips of cloth were wrapped tightly round
   the spaceman's arms and legs outside the spacesuit to stop the
   spacesuit from ballooning when in space.

   There are three theoretical approaches:
     * Hard-shell suits are usually made of metal or composite materials.
       While they resemble suits of armor, they are also designed to
       maintain a constant volume. However they tend to be difficult to
       move, as they rely on bearings instead of bellows over the joins,
       and often end up in odd positions that must be manipulated to
       regain mobility.
     * Mixed suits have hard-shell parts and fabric parts. NASA's
       Extravehicular Mobility Unit uses a fibreglass hard upper torso
       (HUT) and fabric limbs. ILC Dover's I-Suit replaces the hard upper
       torso with a fabric soft upper torso to save weight, restricting
       the use of hard components to the joint bearings, helmet, waist
       seal, and rear entry hatch.
     * Skintight suits, or mechanical counterpressure suits, use a heavy
       elastic body stocking to compress the body. The head is encompassed
       in a pressurized helmet, but the rest of the body is pressurized
       only by the elastic effect of the suit. This eliminates the
       constant volume problem, and reduces the possibility of a space
       suit depressurization. However, these suits are very difficult to
       put on and face problems with providing a constant pressure
       everywhere. Most proposals use the body's natural sweat to keep
       cool. See space activity suit for more information.

   One inconvenience with some spacesuits is the head being fixed facing
   forwards and being unable to turn to look sideways: astronauts call
   this effect "alligator head".

Contributing technologies

   Related preceding technologies include the gas mask used in WWII, the
   oxygen mask used by pilots of high flying bombers in WWII, the high
   altitude or vacuum suit required by pilots of the Lockheed U-2 and
   SR-71 Blackbird, the diving suit, rebreather, scuba diving gear and
   many others.

   The development of the spheroidal dome helmet was key in balancing the
   need for field of view, pressure compensation, and low weight.

   In May 2006, Fabio Sau, a student at the University of North Dakota,
   teamed up with forty other students in five North Dakota schools to
   develop a new spacesuit prototype to demonstrate technologies which
   could be incorporated into a suit used by astronauts that travel to
   Mars. The students worked off of a $100,000 grant by NASA, and the suit
   was tested in the Theodore Roosevelt National Park Badlands of western
   North Dakota. The suit weighs 47 pounds without a life support
   backpack, and costs only a fraction of the standard $22 million cost
   for a NASA spacesuit. The suit was developed in just over a year by
   students from the University of North Dakota, North Dakota State,
   Dickinson State, the state College of Science and Turtle Mountain
   Community College. The mobility of the North Dakota suit can be
   attributed to its low operating pressure; while the North Dakota suit
   was field tested at a pressure of 1 psi differential, NASA's EMU suit
   operates at a pressure of 4.7 psi. To maintain enough oxygen for
   respiration, a functional spacesuit using pure oxygen must maintain a
   minimum pressure of just over 3 psi, equal to the partial pressure of
   oxygen in the Earth's atmosphere.

Spacesuit models of historical significance

High altitude suits

     * Evgeniy Chertanovskiy created his full-pressure suit or
       high-altitude skafander in 1931.
     * Wiley Post experimented with a number of hard-shell designs for
       record-breaking flights

Russian suit models

     * SK-1, the space suit of Yuri Gagarin, the first man in space to
       orbit Earth
     * Berkut, the space suit of Alexey Leonov, the cosmonaut who made
       first the spacewalk.
     * the Yastreb space suit for extra-vehicular activity
     * the Orlan suits for extra-vehicular activity
     * the Sokol suits worn by Soyuz crew members during lift-off and
       re-entry
     * the Strizh space suit developed for pilots of the Buran space
       shuttle

   SK-1 space suit

                  Yastreb suit

                              Orlan space suit

                                              Sokol space suit

American suit models

     * Mercury high-altitude/vacuum suit
     * Gemini spacewalk suits
     * MOL space suits
     * Apollo and Skylab EVA and moon suits
     * Advance Crew Escape System Pressure Suit on the Space Shuttle
     * Shuttle/ISS EMU on both the Space Shuttle and International Space
       Station

   Mercury vacuum suit

   MOL space suit

   Gemini Spacesuit

   Lunar surface suits

   Advance Crew Escape System Pressure Suit

   Shuttle/ISS EMU

Chinese suit models

     * Shenzhou space suit

   Shenzhou space suit

Emerging technologies

     * Hard shell
     * Space activity suit
          + MIT's Bio-Suit
     * ILC Dover's I-Suit

Spacesuits in fiction

   Fiction authors have been trying to design spacesuits since the
   beginning of space fiction, as far as there was need to describe them
   in their stories. Most of them are flexible pressure suits, but usually
   not as bulky as in real spacesuits. Design was influenced by the real
   old-type Siebe Gorman Standard diving dress, including sometimes such
   features as side windows on the helmet.

   Edison's Conquest of Mars (written in 1898) says "... yet since it was
   probable that necessity would arise for occasionally quitting the
   interior of the electrical ships, Mr. Edison had provided for this
   emergency by inventing an air-tight dress constructed somewhat after
   the manner of a diver's suit, but of much lighter material. Each ship
   was provided with several of these suits, by wearing which one could
   venture outside the car even when it was beyond the atmosphere of the
   earth. ...".

   In H.G. Wells's The First Men in the Moon (publ. 1901) the Moon has a
   breathable atmosphere and spacesuits are not needed; the spacecraft has
   an airtight hatch but no airlock. In the film version made in 1964 the
   Moon has no atmosphere and no surface vegetation, and standard diving
   dresses fitted with a big backpack cylinder each are used as
   spacesuits. However clever an idea for a Victorian spacesuit, the idea
   is unworkable. First, film director Nathan Juran failed to provide a
   pressurized atmosphere inside the diving suit of his 1899 astronauts
   (he also forgot any kind of glove). Second, the rubberized material of
   a diving suit would have crumbled upon contact to the cold and vacuum
   of space; the volatiles in the rubberized material would have been lost
   immediately upon space exposure.

   Many fictional spacesuits have two big backpack cylinders as their only
   life-support gear, as if the wearer breathes out to space like in
   ordinary sport open-circuit scuba. In the well-known Dan Dare series
   which started in April 1950 in the `Eagle' comic, the usual Spacefleet
   spacesuit has no backpack, and a corselet like in Standard Diving
   Dress. Comic-strip space story authors often do not know about the
   effects of internal pressure inflating the spacesuit in space, but draw
   the spacesuit in space hanging in folds like a boilersuit: that can
   often be seen in the Dan Dare stories.

   Skintight spacesuits ( skinsuits) appear in the original Buck Rogers
   comics. The Buck Rogers scenario has become familiar enough to cause
   expressions such as "Buck Rogers outfit" for real protective suits that
   look somewhat like spacesuits. Skinsuits are more common in modern
   science fiction. On the other end of the spectrum one can find the
   ideas of heavy powered armor. Robert A. Heinlein's novel Have Space
   Suit-Will Travel draws on his experience designing pressure suits
   during World War II.

   It is possible that fictional spacesuit design influenced real
   spacesuit design somewhat, at least in getting real spacesuits to use a
   hard helmet and not a soft pressurized hood.

   Alien spacesuits in the Gerry Anderson UFO series are filled with a
   breathable liquid to resist acceleration stresses.

   After NASA started, fictional spacesuits often followed real spacesuit
   design, in such features as having a large rectangular backpack. In
   making the spacesuits that are seen in the Dune movie, the prop and
   costume designers stated a need to avoid "that NASA look", and the same
   consideration may have arisen in some other movies and series.

   Spacesuits are commonly used in the Gundam anime metaseries, but are
   often renamed to avoid confusion with space-use mobile suits. In the
   Universal Century timeline, spacesuits are called "normal suits"; the
   After Colony timeline calls them "astrosuit". Gundam spacesuits often
   have a pouch full of adhesive strips, used to temporarily seal tears in
   the suit or cracks in the helmet (as demonstrated in Mobile Suit Gundam
   and Char's Counterattack respectively).

   Retrieved from " http://en.wikipedia.org/wiki/Space_suit"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
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