:: wikimiki.org ::

Spacecraft

Spacecraft

, 2004.]] A spacecraft is a vehicle that travels through space. Spacecraft include robotic or unmanned space probes as well as manned vehicles. The term is sometimes also used to describe artificial satellites, which have similar design criteria.

Overview

The term spaceship is generally applied only to spacecraft capable of transporting people. A space suit has at times been called a miniature spacecraft or spaceship, emphasizing its purpose of keeping its wearer alive while traveling in the vacuum of outer space. The spacecraft is one of the primal elements in science fiction. Numerous short stories and novels are built up around various ideas for spacecraft. Some hard science fiction books focus on the technical details of the craft, while others treat the spacecraft as a given and delve little into its actual implementation.

Examples of past or existing spacecraft

Manned
- Apollo Spacecraft
- Gemini Spacecraft
- International Space Station
- Mir
- Mercury Spacecraft
- Shuttle Buran
- Shenzhou Spacecraft
- Space Shuttle
- Soyuz Spacecraft
- SpaceShipOne
- Voskhod Spacecraft
- Vostok Spacecraft Unmanned
- Cassini-Huygens
- Cluster
- Deep Space 1
- Genesis
- Mars Exploration Rover
- Mars Global Surveyor
- Mars Pathfinder
- Pioneer 10
- Pioneer 11
- Progress
- SOHO
- Stardust
- Viking 1
- Viking 2
- Voyager 1
- Voyager 2
- WMAP

Spacecraft under development

- Crew Exploration Vehicle
- Kliper
- Automated Transfer Vehicle
- H-II Transfer Vehicle
- Ansari X Prize (incl. a list of spacecraft in various stages of completion as of 2005) The US Space Command, according to its "Long Range Plan", is currently planning to develop a weaponized spaceship, which has yet to be announced.[http://www.fas.org/spp/military/docops/usspac/]

External links

- [http://science.hq.nasa.gov/missions/phase.html NASA: Space Science Spacecraft Missions]
- [http://www.skyrocket.de/space/ Gunter's Space Page - Complete information on spacecraft]
- [http://www.cinespaceships.net/ Cinespaceships - Database on spaceships in movie]
- ja:宇宙船

Vehicle

:This article is about the means of transport. For the political meaning, see electoral vehicle. For the economical meaning, see economic vehicle Vehicles are non-living means of transportation. They are most often man-made (e.g. cars, motorcycles, trains, ships, and aircraft), although some other means of transportation which are not made by man can also be called vehicles; examples include icebergs and floating tree trunks. Vehicles may be propelled by animals, e.g. a chariot or an ox-cart. However, animals on their own, though used as a means of transportation, are not called vehicles. This includes humans carrying another human, for example a child or a disabled person. Most land vehicles have wheels. Please see the wheel article for examples of vehicles with and without wheels. Movement without the help of a vehicle or an animal is called locomotion. The word vehicle itself comes from the Latin vehiculum. AVL stands for Automatic Vehicle Location.

Types of vehicles

- Aircraft
- Cars
- Auto rickshaws
- Boats
- Buses
- Coaches
- Motorcycles
- Trains
- Ships
- Vans
- Bicycles
- More...

External Links

- [http://www.epa.gov/greenvehicles/ Green Vehicle Guide]
- [http://www.nhtsa.dot.gov/cars Vehicle Information] Category:Transportation simple:Vehicle

Unmanned space missions

Unmanned space missions are those using remote-controlled spacecraft. Many space missions are more suitable for unmanned missions rather than manned space missions, due to lower cost and lower risk factors. The first such mission was Sputnik I, launched October 4, 1957. Since the early 1970s, most unmanned space missions have been based on space probes with built-in mission computers, and as such may be classified as embedded systems. Some people prefer to use gender-neutral terms such as unpiloted or uncrewed space missions, although the terms are less popular than "unmanned" (as of 2005). Unmanned space missions have been flown by many countries. Most American unmanned missions have been coordinated by the Jet Propulsion Laboratory, and European missions by the European Space Operations Centre, part of ESA (the European Space Agency). The ESA has conducted relatively few space exploration missions (one example is the Giotto mission, which encountered comet Halley). ESA has, however, launched various spacecraft to carry out astronomy, and is a collaborator with NASA on the Hubble Space Telescope. There has been a large number of very successful Russian space missions. There have also been a few Japanese,Chinese and Indian missions. Unmanned space missions may be divided into two classes: artificial satellites, which orbit the Earth, and space probes, which leave Earth's orbit to explore other worlds. See the relevant articles for more information.

External links

- [http://sci.esa.int/home/ourmissions/index.cfm ESA Unmanned Space Missions]
- [http://www.jpl.nasa.gov NASA Jet Propulsion Laboratory]
- [http://www.unmannedspaceflight.com Unmanned spaceflight discussion forum] Category:Space exploration Category:Embedded systems Category:Unmanned vehicles

Manned space missions

Human spaceflight is space exploration with a human crew and possibly passengers, which is in contrast to robotic space probes or remotely-controlled unmanned space missions. On occasion, passengers of other species have ridden aboard spacecraft, although not all survived the return to earth. Dogs, not humans, were the first large mammals launched from Earth. The first human spaceflight was Vostok 1 on April 12, 1961; Soviet cosmonaut Yuri Gagarin made one orbit around the earth. Perhaps the highest of Earth orbits was Gemini 11 in 1966, which reached a height of 1374 km. The Space Shuttle on the missions to launch and service the Hubble Space Telescope has also reached high earth orbit at an altitude of around 600 km. The destination of human spaceflight missions beyond Earth orbit has only been the Moon. On the first such mission, Apollo 8, the crew orbited the Moon. Apollo 10 was the next mission, and it tested the lunar landing craft in lunar orbit without actually landing. The six missions that landed were Apollo 11-17, excluding Apollo 13. On each mission, two of the three astronauts involved landed on the moon; thus, in the late 1960s and early 1970s NASA's Apollo program landed twelve men on the Moon--returning them all to Earth. As of 2005 piloted space missions have been carried out by Russia, the People's Republic of China, and the United States. Missions carried out by the United States are both governmental (NASA) and civilian (Scaled Composites, a California-based company). Canada, Europe, India, and Japan also have active space programs. The Indian Parliament recently sanctioned funds to the Indian Space Research Organization for a human spaceflight by 2008 (although the programme has now been scaled down to start with an unmanned orbiting satellite for surveying--see Chandrayan). Japan has announced a program to place a person on the moon by 2025. Currently the following spacecrafts and spaceports are used:
- International Space Station (includes Soyuz TMA as an emergency lander; normal crew transport with the following two spacecraft)
- Soyuz TMA with Soyuz launch vehicle - Baikonur Cosmodrome
- Space Shuttle - John F. Kennedy Space Center
- Shenzhou spacecraft with Long March rocket - Jiuquan Satellite Launch Center
- Scaled Composites SpaceShipOne with Scaled Composites White Knight (the latter does not enter space itself) - Mojave Spaceport In an attempt to win the $10 million X-Prize, numerous private companies attempted to build their own manned spacecraft capable of repeated sub-orbital flights. The first private spaceflight took place on June 21 2004, when SpaceShipOne conducted a sub-orbital flight. With its second flight within one week, SpaceShipOne captured the prize on October 4, 2004. NASA uses the term "human spaceflight" to refer to its programme of launching people into space. Traditionally, these endeavours have been referred to as "manned space missions". The term "manned" is accurate in terms of gender when speaking of all U.S. spaceflight programs before the Space Shuttle program and Soviet spaceflights before Vostok 6. Although it only denotes gender in one of several definitions of the word, the term "manned" is considered sexist by some, and they may prefer to use the term "crewed"' or "piloted space missions."

External links

- [http://spaceflight.nasa.gov/ NASA Human Space Flight]
- [http://www.thespacereview.com/article/352/1 The top three reasons for humans in space]
- [http://www.chrisvalentines.com/sts107/videoessay.html 20 Minute Video Essay on Human Space Exploration] Category:Human spaceflight

Satellite

A satellite is any object that orbits another object (which is known as its primary). All masses that are part of the solar system, including the Earth, are satellites either of the Sun, or satellites of those objects, such as the Moon. It is not always a simple matter to decide which is the 'satellite' in a pair of bodies. Because all objects exert gravity, the motion of the primary object is also affected by the satellite. If two objects are sufficiently similar in mass, they are generally referred to as a binary system rather than a primary object and satellite; an extreme example is the 'double asteroid' 90 Antiope. The general criterion for an object to be a satellite is that the center of mass of the two objects is inside the primary object. In popular usage, the term 'satellite' normally refers to an artificial satellite (a man-made object that orbits the Earth or another body). However, scientists may also use the term to refer to natural satellites, or moons. This article is primarily concerned with artificial satellites. See natural satellite for information on moons.

Artificial satellites

History of artificial satellites

natural satellite In May, 1946, the Preliminary Design of an Experimental World-Circling Spaceship stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century. The achievement of a satellite craft would produce repercussions comparable to the explosion of the atomic bomb..." (see: Project RAND) The space age began in 1946, as scientists began using captured German V-2 rockets to make measurements in the upper atmosphere. Before this period, scientists used balloons that went up to 30 km and radio waves to study the ionosphere. From 1946 to 1952, upper-atmosphere research was conducted using V-2s and Aerobee rockets. This allowed measurements of atmospheric pressure, density, and temperature up to 200 km. (see also: magnetosphere, Van Allen radiation belt) The U.S. had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy. The Air Force's Project RAND eventually released the above report, but did not believe that the satellite was a potential military weapon; rather they considered it to be a tool for science, politics, and propaganda. In 1954, the Secretary of Defense stated, "I know of no American satellite program." Following pressure by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, military interest picked up and in early 1955 the Air Force and Navy were working on Project Orbiter, which involved using a Jupiter C rocket to launch a small satellite called Explorer 1 on January 31, 1958. On July 29, 1955, the White House announced that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On July 31, the Soviets announced that they intended to launch a satellite by the fall of 1957 and on October 4, 1957 Sputnik I was launched into orbit, which triggered the Space Race between the two nations. The largest artificial satellite currently orbiting the earth is the International Space Station, which can sometimes be seen with the unaided human eye.

Types of satellites

Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects. Communications satellites are artificial satellites stationed in space for the purposes of telecommunications using radio at microwave frequencies. Most communications satellites use geosynchronous orbits or near-geostationary orbits, although some recent systems use low Earth-orbiting satellites. Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc. (See especially Earth Observing System.) Navigation satellites are satellites which use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few metres in real time. Reconnaissance satellites are Earth observation satellite or communications satellite deployed for military or intelligence applications. Little is known about the full power of these satellites, as governments who operate them usually keep information pertaining to their reconnaissance satellites classified. Solar power satellites are proposed satellites built in high Earth orbit that use microwave power transmission to beam solar power to very large antenna on Earth where it can be used in place of conventional power sources. Space stations are man-made structures that are designed for human beings to live on in outer space. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities — instead, other vehicles are used as transport to and from the station. Space stations are designed for medium-term living in orbit, for periods of weeks, months, or even years. Weather satellites are satellites that primarily are used to monitor the weather and/or climate of the Earth. Miniaturized satellites are satellites of unusually low weights and small sizes. New classifications are used to categorize these satellites: minisatellite (500–200 kg), microsatellite (below 200 kg), nanosatellite (below 10 kg).

Orbit types

Many times satellites are characterized by their orbit. Although a satellite may orbit at almost any height, satellites are commonly categorized by their altitude:
- Low Earth Orbit (LEO: 200 - 1200km above the Earth's surface)
- Medium Earth Orbit (ICO or MEO: 1200 - 35286 km)
- Geosynchronous Orbit (GEO: 35786 km above Earth's surface)
- Geostationary Orbit (GSO: zero inclination geosynchronous orbit)
- High Earth Orbit (HEO: above 35786 km) The following orbits are special orbits that are also used to categorize satellites:
- Molniya orbits
- Heliosynchronous or sun-synchronous orbit
- Polar orbit
- LTO lunar transfer orbit
- Hohmann transfer orbit For this particular orbit type, it is more common to identify the satellite as a spacecraft.
- Supersynchronous orbit or drift orbit - orbit above GEO. Satellites will drift in a westerly direction.
- (GEO + 235 km + (1000 × CR × A/m) km)
- where CR is the solar pressure radiation coefficient (typically between 1.2 and 1.5) and A/m is the aspect area [m²] to dry mass [kg] ratio
- Subsynchronous orbit or drift orbit - orbits close to but below GEO. Used for satellites undergoing station changes in an eastern direction. Satellites can also orbit libration points.

Countries with satellite launch capability

This list includes counties with an independent capability to place satellites in orbit, including production of the necessary launch vehicle. Many more countries have built satellites that were launched with the aid of others. The French and British capabilities are now subsumed by the European Union under the European Space Agency. In 1998, North Korea claimed to have launched a satellite, but this was never confirmed, and widely believed to be a cover for the test launch of the Taepodong-1 missile over Japan (See Kwangmyongsong).

Reference

External links

- [http://science.nasa.gov/Realtime/JPass/20/ J-Pass] NASA site for satellite-watching
- [http://www.stoff.pl Orbitron - Satellite Tracking System] Free satellite tracking software
- [http://ilectric.com/glance/Recreation/Radio/Amateur/Satellite_Tracking/ Satellite Tracking in Recreation Radio Amateur] an excellent link to many links
- [http://www.oosa.unvienna.org UN Office for Outer Space Affairs] ensures all countries benefit from satellites
- [http://www.satellite-service-providers.com/ Satellite Service Providers] Compare and review on top satellite tv, radio and internet service providers] Category:Satellites Category:Unmanned vehicles ko:인공 위성 ja:人工衛星

Space suit

]] A space suit is a complex system of garments and 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 by people such as high-altitude fighter pilots who may fly so high that breathing pure oxygen at surrounding pressure would not provide enough oxygen for them to function: see hypoxia.

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.
- breathable oxygen. Usually a rebreather is used along with a supply of fresh oxygen.
- 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, a space suit almost always has only a cooling system and heavy insulation on the hands and possibly feet.
- electromagnetic 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. The only way this is possible is for the space suit to maintain a constant volume no matter what position the wearer is in. 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 hard-shell torso and fabric limbs.
- 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. scuba

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, first man in space orbits Earth
- Berkut, the space suit of Alexey Leonov, the cosmonaut who made first 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 Buran space shuttle
- Mercury high-altitude/vacuum suit
- Gemini spacewalk suits
- Apollo lunar surface suits
- Skylab
- Advance Crew Escape System Pressure Suit on the Space Shuttle
- Emerging technologies
- Hard shell
- Space activity 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. In H.G. Wells's The First men in the Moon (publ. 1901) Standard Diving Dresses are fitted with a big backpack cylinder each and used as spacesuits. 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 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.

External links

- [http://www.zvezda-npp.ru/english/04.htm Russian Space Suits]
- [http://www.jsc.nasa.gov/history/hsf_history.htm NASA JSC Oral History Project]: See link near page end to Walking to Olympus: An EVA Chronology PDF document.
- [http://spaceboy.nasda.go.jp/note/yujin/e/yuj101_eva_e.html NASDA Online Space Notes]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730064704_1973064704.pdf Apollo Extravehicular mobility unit. Volume 1: System description - 1971 (PDF document)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730064705_1973064705.pdf Apollo Extravehicular mobility unit. Volume 2: Operational procedures - 1971 (PDF document)]
- [http://trs.nis.nasa.gov/archive/00000173/01/tmx64855.pdf Skylab Extravehicular Activity Development Report - 1974 (PDF document)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900001621_1990001621.pdf Analysis of the Space Shuttle Extravehicular Mobility Unit - 1986 (PDF document)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940017339_1994017339.pdf NASA Space Shuttle EVA tools and equipment reference book - 1993 (PDF document)] ---- "Space Suit" is an instrumental track from They Might Be Giants' 1992 album Apollo 18. Category:Environmental suits Category:Space exploration Category:Spacecraft components ja:宇宙服

Vacuum

For other uses, see vacuum cleaner and Vacuum (musical group). The root of the word vacuum is the Latin word vacuum (pl. vacua) which means a space devoid of matter. In physics, a vacuum is the absence of matter in a volume of space.

Vacuum ranges

Vacuum ranges are defined as follows:

Perfect vacuum

A perfect vacuum is an ideal state that cannot practically be obtained in a laboratory, nor even in outer space, where there are a few hydrogen atoms per cubic centimeter at 10⁻¹⁴ pascal or 10⁻¹⁶ torr. In modern day usage vacuum is considered to exist in an enclosed space or chamber, when the pressure of gaseous environment is lower than atmospheric pressure (760 Torr or 101 kPa), or has been reduced as much as necessary to prevent the influence of some gas on a process being carried out in that space.

Partial vacuum

Physicists use the term partial vacuum to describe real-life non-ideal vacuum. A complete characterization of the physical state would require further parameters, such as temperature. The antithesis of a vacuum, which is also an ideal unachievable state, is called a plenum. In engineering, a vacuum is any region where the gas pressure is less than atmospheric pressure. Engineers measure the degree of vacuum in units of pressure. The SI unit of pressure is the pascal (abbreviation Pa), but vacuum is usually measured in millimeters of mercury (mmHg) or torr, with 1 mmHg or 1 torr equaling 133.3223684 pascals. It is often also measured using the barometric scale, or as a percentage of atmospheric pressure in bars or atms. For commercial purposes, vacuum is often measured in inches of mercury (inHg). This means that the pressure in vacuum, when specified in inches of mercury, is equal to the specified inches of mercury subtracted from 29.92. Thus a vacuum of 26 inHg is equivalent to a pressure of (29.92 - 26) or 3.92 inHg. Here, 29.92 inHg means perfect vacuum.

Degrees of vacuum

- Atmospheric pressure = variable, but standardised at 101.325 kPa (760 Torr) or 760 mm of mercury
- Vacuum cleaner = approximately 80 kPa (600 Torr)
- Mechanical vacuum pump = approximately 100 Pa to 100 μPa (1 Torr to 10⁻⁶ Torr)
- Near earth outer space = approximately 100 μPa (10⁻⁶ Torr)
- Cryopumped MBE chamber = 100 nPa to 1 nPa (10⁻⁹ Torr to 10⁻¹¹ Torr)
- Pressure on the Moon = approximately 1 nPa (10⁻¹¹ Torr)
- Interstellar space = approximately 1 fPa (10⁻¹⁷ Torr)
- [http://www-ssg.sr.unh.edu/ism/what1.html Source for interstellar vacuum] As gas pressure decreases, the mean free path (MFP) of the gas molecules increases. When the MFP is greater than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. In interplanetary and interstellar space, isotropic gas pressure is insignificant when compared to solar pressure, solar wind, and dynamic pressure. Astrophysicists prefer to use density to describe these environments, in units of particles per cubic metre.

Creating a vacuum

The easiest way to create an artificial vacuum is to expand the volume of a container. For example, your muscles expand your lungs to create a partial vacuum inside them, and air rushes in to fill the vacuum. By repeatedly closing off a compartment of the vacuum and exhausting it, it is possible to pump air out of a chamber of fixed size in a manner analogous to pumping a milkshake out of a glass. This is the principle behind most mechanical vacuum pumps. Inside the pump, a mechanism expands a small sealed cavity to create a deep vacuum. Because of the pressure differential, some air from the chamber is pushed into the pump's small cavity. The pump's cavity is then sealed from the chamber, opened to the atmosphere, and squeezed back to a minute size. A mechanical vacuum pump moves the same volume of gas with each cycle, but as the chamber's pressure drops, this volume contains less and less mass. So although the pumping speed remains constant when measured in litres/second, it drops exponentially when measured in kilograms/second. Meanwhile, the leakage rates, evaporation rates, and sublimation rates produce a constant mass flow into the system. When the pump's mass flow drops to the same level as the mass flows into the chamber, the system asymptotically approaches a constant pressure called the base pressure. Evaporation and sublimation into a vacuum is called outgassing, and the most common source is water absorbed by materials in the chamber. Outgassing can be reduced by desiccation prior to vacuum pumping. The base pressure of a rubber- and plastic-sealed piston pump system is typically 1 to 50 kPa, while a scroll pump might reach 10 Pa and a rotary vane oil pump with a clean and empty metallic chamber can easily achieve 0.1 Pa. If the dominant mass flow into the vacuum system is chamber leakage or outgassing of materials under vacuum, then the vacuum can be improved simply by installing bigger pumps. However, there is a point where backstream leakage through the pump and outgassing of the pump oils become the dominant mass flows into the chamber. In this situation, the vacuum will approach the pump's ultimate pressure - the best vacuum that this type of pump can achieve under ideal conditions. Adding more pumps in parallel or bigger pumps of the same type can still improve the pump-down speed, but they will not reduce the base pressure below ultimate. Better pumping technologies must be used to go beyond this barrier.

High vacuum

Fortunately, once the pressure has dropped below 1 kPa or so, another vacuum pumping technique becomes possible. Matter flows differently at different pressures based on the laws of fluid dynamics. At atmospheric pressure and mild vacuums, molecules interact with each other and push on their neighboring molecules in what is known as viscous flow. When the distance between the molecules increases, the molecules interact with the walls of the chamber more often than the other molecules, and molecular pumping becomes more effective than compression pumping. This regime is generally called high vacuum. One such method to create a high vacuum to ultra high vacuum is by the use of cryopumps. Cryopumping incorporates the use of introducing cryogenics and a vacuum system. On a larger scale, the principles are the same as in a Cryomodule Molecular pumps sweep out a larger area than mechanical pumps, and do so more frequently, making them capable of much higher pumping speeds as measured in volume per time. They do this at the expense of the seal between the vacuum and their exhaust. Since there is no seal, a small pressure at the exhaust can easily force flow backstream through the pump; this is called stall. In high vacuum, however, pressure gradients have little effect on fluid flows, and molecular pumps can attain their full potential. The two main types of molecular pumps are the diffusion pump and the turbomolecular pump. Both types of pumps blow out gas molecules that diffuse into the pump. Diffusion pumps blow out molecules with jets of oil, while turbomolecular pumps use high speed fans. Both of these pumps will stall and fail to pump if exhausted directly to atmospheric pressure, so they must be exhausted to a lower grade vacuum created by a mechanical pump. As with mechanical pumps, the base pressure will be reached when leakage, outgassing, and backstreaming equal the pump speed, but now minimizing leakage and outgassing to a level comparable to backstreaming becomes much more difficult. High vacuum systems generally require metal chambers with metal O-ring seals such as Klein flanges or ISO flanges. The system must be clean and free of organic matter to minimize outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. As a result, many materials that work well in low vacuums, such as epoxy, will become a problematic source of outgassing when attempting to achieve high vacuums. With these standard precautions, vacuums of 1 mPa are easily achieved with off-the-shelf molecular pumps. With careful design and operation, 1μPa is possible.

Ultra-high vacuum

:Main article: Ultra high vacuum Even higher vacuums are possible, but they generally require custom-built equipment, strict operational procedures, and a fair amount of trial-and-error. Yet more specialized pumps become useful: # Converting the molecules of gas to their solid phase by freezing them, called cryopumping or cryotrapping # Converting them to solids by electrically combining them with other materials, called ion pumping Ultra-high vacuum systems are usually made of stainless steel with metal-gasketed conflat flanges. The system is usually baked, preferably under vacuum, to temporarily raise the vapour pressure of all outgassing materials in the system and boil them off. If necessary, this outgassing of the system can also be performed at room temperature, but this takes much more time. Once the bulk of the outgassing materials are boiled off and evacuated, the system may be cooled to lower vapour pressures and minimize residual outgassing during actual operation. Some systems are cooled well below room temperature by liquid nitrogen to shut down residual outgassing and simultaneously cryopump the system. In ultra-high vacuum systems, some very odd leakage paths and outgassing sources must be considered. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the absorptivity of hard metals such as stainless steel or titanium must be considered. Some oils and greases will boil off in extreme vacuums. The porosity of the metallic chamber walls may have to be considered, and the grain direction of the metallic flanges should be parallel to the flange face. The impact of molecular size must be considered. Smaller molecules can leak in more easily and are more easily absorbed by certain materials, and molecular pumps are less effective at pumping gases with lower molecular weights. Your system may be able to evacuate nitrogen, (the main component of air,) to the desired vacuum, but your chamber could still be full of residual atmospheric hydrogen and helium. Vessels lined with a highly gas-permeable material such as palladium (which is a high-capacity hydrogen sponge) create special outgassing problems. The lowest pressures currently achievable in laboratory are about 10^-13 Pa.

Vacuum in space

Pa Much of outer space has the density and pressure of an almost perfect vacuum. It is cold and has no friction. The properties of the vacuum remain largely unknown. A perfect vacuum is an ideal state that cannot practically be obtained in a laboratory, nor even in outer space, where there are a few hydrogen atoms per cubic centimeter at 10−14 pascal or 10−16 torr. All of the observable universe is also filled with large numbers of photons, the so-called cosmic background radiation, and quite likely a correspondingly large number of neutrinos. The current temperature is about 3 K, being merely 3 degrees above the absolute zero of temperature. Neither these photons nor the neutrinos produce a significant interaction with matter, so stars, planets and spacecraft move freely in this near perfect vacuum of interstellar space. Stars, planets and moons keep their atmosphere by gravitational attraction, so atmospheres have no firm boundary. The density of gas decreases with distance from the object. In Low Earth Orbit (about 300 km altitude) the atmospheric density is still sufficient to produce significant drag on satellites. Most Earth satellites operate in this region, and they need to fire their engines every few days to maintain orbit. The atmosphere in Low Earth Orbit is increasingly being polluted with man-made debris. Studies have discovered that some satellites retrieved from orbit are coated with a very thin layer of urine and fecal matter evidently released from Russian and US space missions. [http://see.msfc.nasa.gov/sparkman/Section_Docs/article_1.htm] Beyond planetary atmospheres, the pressure from photons and other particles from the sun become significant. Spacecraft can be buffeted by solar winds, but planets are too massive to be affected. The idea of using this wind with a solar sail has been proposed for interplanetary travel. The deep vacuum of space could make it an attractive environment for certain processes, for instance those that require ultraclean surfaces. In 1913, Norwegian explorer and physicist Kristian Birkeland may have been the first to predict that space is not only a plasma, but also contains "dark matter". He wrote: "It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. We have assumed that each stellar system in evolutions throws off electric corpuscles into space. It does not seem unreasonable therefore to think that the greater part of the material masses in the universe is found, not in the solar systems or nebulae, but in "empty" space. (See "Polar Magnetic Phenomena and Terrella Experiments", in The Norwegian Aurora Polaris Expedition 1902-1903 (publ. 1913, p.720)

The quantum-mechanical vacuum

Even an ideal vacuum, thought of as the complete absence of anything, will not in practice remain empty. One reason is that the walls of a vacuum chamber emit light in the form of black-body radiation: visible light if they are at a temperature of thousands of degrees, infrared light if they are cooler. If this soup of photons is in thermodynamic equilibrium with the walls, it can be said to have a particular temperature, as well as a pressure. More fundamentally, quantum mechanics predicts that vacuum energy can never be exactly zero. The lowest possible energy state is called the zero-point energy and consists of a seething mass of virtual particles that have brief existence. This is called vacuum fluctuation. While most agree that this represents a significant part of particle physics, it is a concept that would benefit from a deeper understanding than currently available. Vacuum fluctuations may also be related to the so-called cosmological constant in the theory of gravitation, if indeed this entity were to be observed in nature on a macroscopic scale. The best support for vacuum fluctuations is the Casimir effect. In quantum field theory and string theory, the term "vacuum" is used to represent the ground state in the Hilbert space, that is, the state with the lowest possible energy. In free (non-interacting) quantum field theories, this state is analogous to the ground state of a quantum harmonic oscillator. If the theory is obtained by quantization of a classical theory, each stationary point of the energy in the configuration space gives rise to a single vacuum. String theory is believed to be analogous to quantum field theory but one with a huge number of vacua - with the so-called anthropic landscape.

Historical interpretation

Historically, there has been much dispute over whether such a thing as a vacuum can exist. Ancient Greek philosophers did not like to admit the existence of a vacuum, asking themselves "how can 'nothing' be something?". Plato found the idea of a vacuum inconceivable. He believed that all physical things were instantiations of an abstract Platonic ideal, and could not imagine an "ideal" form of a vacuum. Similarly, Aristotle considered the creation of a vacuum impossible—nothing could not be something. Later Greek philosophers thought that a vacuum could exist outside the cosmos, but not inside it. In the Middle Ages, the idea of a vacuum was thought to be immoral or even heretical. The absence of anything implied the absence of God, and hearkened back to the void prior to the story of creation in the book of Genesis. Medieval thought experiments into the idea of a vacuum considered whether a vacuum was present, if only for an instant, between two flat plates when they were rapidly separated. There was much discussion of whether the air moved in quickly enough as the plates were separated, or, following William Burley whether a 'celestial agent' prevented the vacuum arising—that is, whether nature abhorred a vacuum. This speculation became irrelevant after the Paris condemnations of Bishop Tempier, which required there to be no restrictions on the powers of God, which led to the conclusion that God could create a vacuum if he so wished. Following work by Galileo, Evangelista Torricelli argued in 1643 that there was a vacuum at the top of a mercury barometer. Some people believe that although Torricelli produced the first vacuum, it was Blaise Pascal who recognized it for what it was. Robert Boyle later conducted experiments on the effects of a vacuum. For example, a canary exposed to vacuum would rupture open due to the lack of pressure. In 1654, Otto von Guericke conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been evacuated. Concurrently, theories of the nature of light had proposed the idea of a aethereal medium which would be the medium to convey waves of light (Newton relied on this idea to explain refraction and radiated heat). This evolved into the luminiferous aether idea of the 19th century, but it was known to have significant shortcomings. In 1887 the Michelson-Morley experiment, using an interferometer to attempt to detect the change in the speed of light caused by the Earth moving with respect to the aether, was a famous null result, showing that there really was no static, pervasive medium throughout space and through which the Earth moved as though through a wind. (Of course, if the aether were the medium in which light waves traveled and electromagnetic and gravitational fields manifest, then it would be exceedingly difficult to distinguish the characteristics of such medium from those of the field or fields one was in. It would no more be possible to show that the Earth moved in relation to such an aether than it would be to illustrate that it moved in relation to its own electromagnetic and gravitational fields.)

External links

- [http://www.avs.org/ American Vacuum Society]
- [http://scitation.aip.org/jvsta/ Journal of Vacuum Science and Technology A]
- [http://scitation.aip.org/jvstb/ Journal of Vacuum Science and Technology B]
- [http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html Discussion of the effects on humans of exposure to hard vacuums].
- [http://www.arXiv.org/abs/hep-th/0012062 Vacuum Energy in High Energy Physics]
- [http://vacuumscientists.com/ Scientist of vacuum]
- http://www.mcallister.com/vacuum.html (Short History of Vacuum Terminology and Technology) Category:Industrial processes ja:真空

Short story

A short story is a form of short fictional narrative prose. Short stories tend to be more concise and to the point than longer works of fiction, such as novellas and novels. Because of their brevity, successful short stories rely on literary devices such as character, plot, theme, language, and insight to a greater extent than long form fiction. Famous modern English-language short stories include The Snows of Kilimanjaro by Ernest Hemingway, An Occurrence at Owl Creek Bridge by Ambrose Bierce, "The Dead" by James Joyce, To Build A Fire by Jack London, and A Rose for Emily by William Faulkner. Short stories have their origins in the prose anecdote, a swiftly-sketched situation that comes rapidly to its point, with parallels in oral story-telling traditions. With the rise of the comparatively realistic novel, the short story evolved as a miniature, with some of its first perfectly independent examples in the tales of E.T.A. Hoffman and Edgar Allan Poe.

History

Short stories date back to the oral story-telling traditions which produced such notable tales as Homer's the Iliad and the Odyssey. Tales such as these were told in a rhyming, poetic format, with the rhymes acting as a mnemonic tool for people to remember the story. Short sections of these tales focused on individual narratives that could be told at one sitting. The overall arch of the story would only emerge through the telling of multiple sections of the tale. Two ancient forms of short stories which did not exist within a larger narrative format are the fable and the anecdote. Fables, which tend to be folk tales with an explicitly expressed moral, were said by the Greek historian Herodotus to have been invented by a Greek slave named Aesop in the 6th century BCE (although other times and nationalities are also given for Aesop). These ancient fables are known today as Aesop's Fables. The other ancient form of short story, anecdotes, were popular during the years of the Roman Empire. Anecdotes functioned as a sort of parable, a brief realistic narration that embodies a point. Many of the surviving Roman anecdotes were later collected in the Gesta Romanorum in the 13th or 14th century. Anecdotes remained popular in Europe well into the 18th century, when the fictional anecdotal letters of Sir Roger de Coverley were published. In Europe, the oral story-telling tradition began to transition into written stories in the early 14th century, most notably with Geoffrey Chaucer's Canterbury Tales and Giovanni Boccaccio's Decameron. Both of these books are composed of individual short stories (which range from farce or humorous anecdotes to well-crafted literary fictions) set within a larger narrative story (a frame story), although the frame tale device was not adopted by all writers. At the end of the 16th century, some of the most popular short stories in Europe were the darkly tragic "novella" of Matteo Bandello (especially in their French translation). During the Renaissance, the term novella was used when referring to short stories. The mid 17th century in France saw the development of a refined short novel, the "nouvelle", by such authors as Madame de Lafayette. In the 1690s, traditional Fairy tales began to be published (one of the most famous collections was by Charles Perrault). The appearance of Antoine Galland's first modern translation of the Thousand and One Nights (or "Arabian Nights") (from 1704; another translation appeared in 1710-12) would have an enormous influence on the 18th century European short stories of Voltaire, Diderot and others.

Modern short stories

Modern short stories emerged as their own genre in the early 19th century. Early examples of short story collections include the Brothers Grimm Fairy Tales (1824-1826), Nathaniel Hawthorne's Twice Told Tales (1842), Edgar Allan Poe's Tales of the Grotesque and Arabesque (1836), and Guy de Maupassant's La Maison Tellier (1881). In the later part of the 19th century, the growth of print magazines and journals created a strong market demand for short fiction between 3,000 and 15,000 words in length. Among the famous short stories to come out of this time period was Ward No. 6 by Anton Chekhov. In the first half of the 20th Century, a number of high-profile magazines, such as The Atlantic Monthly, Scribner's, and The Saturday Evening Post, all published short stories in each issue. The demand for quality short stories was so great, and the money paid for them so high, that F. Scott Fitzgerald repeatedly turned to short story writing to pay off his numerous debts. The demand for short stories by print magazines hit its peak in the middle of the 20th century, when in 1952 Life Magazine published Ernest Hemingway's long short story (or novella) The Old Man and the Sea. The issue containing this story sold 5,300,000 copies in only two days. Since then, the number of commercial magazines that publish short stories has declined, even though several well-known magazines like The New Yorker continue to feature them. Literary magazines also provide a showcase for short stories. In addition, short stories have recently found a new life online, where they can be found in online magazines, in collections organized by author or theme, and on blogs.

Elements and characteristics

Short stories tend to be less complex than novels. Usually, a short story will focus on only one incident, has a single plot, a single setting, a limited number of characters, and covers a short period of time. In longer forms of fiction, stories tend to contain certain core elements of dramatic structure: exposition (the introduction of setting, situation and main characters); complication (the event of the story that introduces the conflict); rising action, crisis (the decisive moment for the protagonist and their commitment to a course of action); climax (the point of highest interest in terms of the conflict and the point of the story with the most action); resolution (the point of the story when the conflict is resolved); and moral. Because of their short length, short stories may or may not follow this pattern. For example, modern short stories occasionally have an exposition. More typical, though, is an abrupt beginning, with the story starting in the middle of the action. As with longer stories, plots of short stories also have a climax, crisis, or turning-point. However, the endings of many short stories are abrupt and open and may or may not have a moral or practical lesson. Of course, as with any art form, the exact characteristics of a short story will vary by author.

Length

Determining what exactly separates a short story from longer fictional formats is problematic. A classic definition of a short story is that it must be able to be read in one sitting. Other definitions place the maximum word length (or number of words in the story) at 7,500 words. In contemporary usage, the term short story most often refers to a work of fiction no longer than 20,000 words (at one extreme) and no shorter than 1,000. Stories shorter than 1,000 words fall into the flash fiction genre. Fiction surpassing the maximum word length parameters of the short story falls into the areas of novelettes, novellas, or novels.

Genres

Short stories are most often a form of fiction writing, with the most widely published form of short stories being genre fiction such as science fiction, horror fiction, detective fiction, and so on. The short story has also come to embrace forms of non-fiction such as travel writing, prose poetry and postmodern variants of fiction and non-fiction such as ficto-criticism or new journalism.

Examples of classic short stories

- [http://xroads.virginia.edu/~drbr/wf_rose.html A Rose for Emily] by William Faulkner
- [http://xroads.virginia.edu/~DRBR/heming.html The Snows of Kilimanjaro] by Ernest Hemingway, the classic stream-of-consciousness short story
- [http://www.underthesun.cc/Classics/Jackson/lottery The Lottery] by Shirley Jackson
- [http://xroads.virginia.edu/~DRBR/goodman.html A Good Man Is Hard to Find] by Flannery O'Connor
- [http://www.auburn.edu/~vestmon/Gift_of_the_Magi.html The Gift of the Magi] by O. Henry (William Sydney Porter)
- [http://www.literature.org/authors/poe-edgar-allan/tell-tale-heart.html The Tell-Tale Heart] by Edgar Allan Poe
- [http://art-bin.com/art/or_weltypostoff.html Why I live at the P.O.] by Eudora Welty

Other resources

- [http://www.storysouth.com/millionwriters.html Million Writers Award for best online short story of the year]
- [http://titan.iwu.edu/~jplath/sschron.html Chronology of American short stories]
- [http://www.short-stories.co.uk Large online library of contemporary and classic short stories]
- [http://www.the-short-story.com/en/index.html Also an online library of contemporary and classic short stories]
- [http://www.gutenberg.org/catalog/world/results?title=short+stories Short Story eTexts] at Project Gutenberg
- [http://www.gutenberg.org/catalog/world/results?subject=short+stories More Short Story eTexts] at Project Gutenberg
- [http://www.chabad.org/library/article.asp?AID=109851 Jewish Chassidic Stories]

Novel

A novel (from French nouvelle, "new") is an extended fictional narrative in prose. Down into the 18th century, the word referred specifically to short fictions of love and intrigue as opposed to romances—epic-length works about love and adventures. Having become one of the major literary genres over the past 200 years the novel is today the object of discussions demanding artistic merits, a specific literary style and a deeper meaning than a true story of the same content could claim to have. __TOC__

Novel/Romance: Unstable Words

One meaning of the English word novel has remained stable: novel can still signify what is new due to its "novelty". When it comes to fiction, though, the meaning of the term has changed over time:
- The period 1200-1750 saw a rise of the novel (originally a short piece of fiction) rivalling the romance (the epic-length performance): this development, which one could describe as the first rise of the novel, occurred across Europe, though only the Spanish and the English went one step further and allowed the word novel (or, in Spanish, novela) to become their regular term for fictional narratives.
- The period 1700-1800 saw the rise of a "new romance" in reaction against the potentially scandalous production of novels. The movement encountered a complex situation in the English market, where the term "new romance" could hardly be ventured, after the novel had done so much to transform taste. The new genre adopted the name novel: this new novel was a work of new epic proportions, with the effect that the English (and Spanish) finally needed a new word for the original short "novel": The term novella was finally created to fill the gap in English. "Short story" brought a further refinement. The meaning of the term romance changed within the same complex process, becoming the word for a love story whether in life or fiction. Other meanings include the musicologist's genre "Romance" of a short and amiable piece, or Romance languages for the languages derived from Latin (French, Spanish, Italian, Romanian, and so forth).

History

Traditions of Prose Fiction: The Ancient World

As Pierre Daniel Huet noted in 1670, the tradition of epic works went back as far as Virgil and Homer. The regular format was verse, suiting the purpose of tradition in a culture of oral performances. Today, we see this tradition as going back even further, to the epic of Gilgamesh. It is more difficult to speak of the influence of the shorter performances of regular storytelling on the medieval traditions which led to the development of the novel/novella. There was a third tradition of prose fictions, both in a satirical mode (with Petronius's Satyricon and the incredible stories of Lucian of Samosata), and a heroic strain (with the romances of Heliodorus and Longus). The ancient Greek romance was revived by Byzantine novelists of the 12th century. All of these traditions were then rediscovered in the 17th and 18th centuries, ultimately influencing the modern book market.

The Romance, 1100-1500

The word romance seems to have become the label of romantic fictions because of the "Romance" language in which early (11th and 12th century) works of this genre were composed. The most fashionable genres developed in southern France in the late 12th century and spread east- and northwards with translations and individual national performances. Subject matter such as Arthurian knighthood had already at that time traveled in the opposite direction, reaching southern France from Britain and French Britanny. As a consequence, it is particularly difficult to determine how much the early "romance" owed to ancient Greek models and how much to such northern folkloric verse epics as Beowulf and the Nibelungenlied. The standard plot of the early romance was a series of adventures. Following a plot framework as old as Heliodorus, and so durable as to be still alive in Hollywood movies, a hero would undergo a first set of adventures before he met his lady. A separation would follow, with a second set of adventures leading to a final reunion. Variations kept the genre alive. Unexpected and peculiar adventures surprised the audience with romances like Sir Gawain and the Green Knight. Classics of the romance developed such as the Roman de la Rose, written first in French, and famous today in English thanks to the translation by Geoffrey Chaucer. These original romances were verse works, adopting a "high language" thought suitable to heroic deeds, and to inspire the emulation of virtues; prose was considered "low", more suitable for satire). Verse allowed the culture of oral traditions to live on, yet it became the language of authors who carefully composed their texts—texts to be spread in writing, thus to preserve the careful artistic composition. The subjects were aristocratic. The textual tradition of ornamented and illustrated handwritten books afforded patronage by the aristocracy or by the monied urban class developing in the 13th and 14th centuries, for whom knight errantry most clearly was a world of fiction and fantasy. The 14th and 15th centuries saw the emergence of first prose romances, a genre rose along with a new book market. This market had developed even before the first printing facilities were introduced: prose authors could speak a new language, a language avoiding the repetition inherent in rhymes. Prose could risk a new rhythm and longer thoughts. Yet it needed the written book to preserve the coincidental formulations the author had chosen. Whilst the printing press was still to come, a commercial book production trade had developed. Legends, lives of saints and mystical visions in prose were the main object of the new market of prose productions. The urban elite, female readers in upper class households and monasteries read religious prose. Prose romances appeared as a new and expensive fashion on this market. They could only truly flourish with the invention of the printing press and with paper becoming a cheaper medium. Both of these achievements arrived in the late 15th century, when the old romance was already facing fierce competition from a number of shorter genres; most salient among these genres was the novel, a form that arose in the course of the 14th century.

The Emergence of the Novel, 1200-1500

Legend It is difficult to give a full catalog of the genres that finally culminated—with the works of Boccaccio, Geoffrey Chaucer, Niccolò Machiavelli and Miguel de Cervantes—in the "novel" as known today . The early novel was basically any story told for its spectacular or revealing incidents. The original environment—living on with the typical frame settings—was the entertaining conversation. Stories of grave incidents could just as well augment sermons. Collections of examples facilitated the work of preachers in need of such illustrations. A fable could illustrate a moral conclusion; a short historical reflection could do the same. A competition of genres developed. Tastes and social status were—if one believes the medieval collections—decisive. The working classes loved their own brand of drastic stories: stories of clever cheating, wit and ridicule levelled against hated social groups (or competitors among the story tellers). Much of the original genre is still alive with the short joke told in everyday life to make a certain humorous point in a conversation. Artistic performances included the story within a story: situations in which a series of stories was allegedly told. They rejoiced in a broad pattern of tastes and genres. The Canterbury Tales constitute a classic example, with their noble storytellers fond of "romantic" stories and their lower narrators preferring stories of everyday life. The genre did not have its own generic term. "Novel" would simply denote the novelty of the accident narrated. The inclusion of frame stories, however, brought an awareness of the fact that genres were developing in this field. The main advantage of the background story was the justification it put into the hands of the actual authors such as Chaucer and Boccaccio. Romances afforded lofty language and relied on an accepted notion of what deserved to be read as high style. Yet what if the taste in moral teachings and poetry changed? Romances quickly outdated. Stories of cheats and pranks, illicit love affairs, and clever intrigues in which certain respectable professions or the citizens of another town were made fun of were, on the other hand, neither morally nor poetically justifiable. They carried their justification outside. The story teller would offer a few words why he thought this story was worth being told. Again, Chaucer's Canterbury Tales afford the best examples: the real author could tell stories without any other justification than that this story gave a good portrait of the person who told it and of his or her taste—and that justification would remain stable throughout history. If lofty performances grew tedious—as they did in the 14th and 15th centuries with the old plots never leading to newer ones—the collections of tales or novels made it easy to criticise the lofty performances and to reduce their status: one of the group of narrators (created by the actual author) could start with the romantic story only to be interrupted by the other narrators listening within the story. They might silence him or order him to speak a language they liked, or they might ask him to speed up and to make his point. The result was a rise of the short genre. The steps of this development can be noted with the short story gaining appreciation and the value to rival romances in new versified collections at the end of the 14th century.

The First Rise of the Novel, 1500-1750

The Canterbury Tales The invention of printing subjected both novels and romances to a first wave of trivialisation and commercialisation. Printed books were expensive, yet something people would buy, just as people still buy expensive things they can barely afford. Alphabetisation, or the rise of literacy, was a slow process when it came to writing skills, but was faster as far as reading skills were concerned. The Protestant Reformation afforded readers of religious pamphlets, newspapers and broadsheets. The urban population learned to read, but did not aspire to participation in the world of letters. The market of chapbooks developing with the printing press comprised both romances and little histories, tales and fables. Woodcuts were the regular ornament and they were offered without much care. A romance in which the heroic knight had to fight more than ten duels within a few pages could get the same illustration of such a fight again and again if the printers stock of standard illustrations was small. As their stocks grew, printers repeated the same illustrations in other books with similar plots, mixing these illustrations without respect to style. You can open 18th century chapbooks and find illustrations from the early years of printing next to more modern ones. Romances were reduced to cheap and abrupt plots resembling modern comic books. Neither were the first collections of novels necessarily prestigious projects. They appeared with an enormous variety from folk tales over jests to stories told by Boccaccio and Chaucer, now venerable authors. comic book comic book comic book A more prestigious market of romances developed in the 16th century, with multi-volume works aiming at an audience which would subscribe to this production. The criticism levelled against romances by Chaucer's pilgrims grew in response both to the trivialisations and to the extended multi-volume "romances". Romances like the Amadis de Gaula led their readers into dream worlds of knighthood and fed them with ideals of a past no one could revitalise, or so the critics complained. Italian authors like Machiavelli were among those who brought the novel into a new format: while it remained a story of intrigue, ending in a surprising point, the observations were now much finer: how did the protagonists manage their intrigue? How did they keep their secrets, what did they do when others threatened to discover them? The whole question of novels and romances became critical when Cervantes added his Novelas Exemplares (1613) to the two volumes of his Don Quixote (1605/15). The famous satirical romance was levelled against the Amadis which had made Don Quixote lose his mind. Advocates of the lofty romance would, however, claim that the satirical counterpart of the old heroic romance could hardly teach anything: Don Quixote neither offered a hero to be emulated nor did it satisfy with beautiful speeches; all it could do was to make fun of lofty ideals. The Novelas Exemplares offered an alternative between the heroic and the satiric mode, yet critics were even less sure about what to make of this production. Cervantes told stories of adultery, jealousy and crime. If these stories were to give examples, they gave examples of immoral actions. The advocates of the "novel" responded that their stories taught both with good and with bad examples. The reader could still feel compassion and sympathy with the victims of crimes and intrigues, if evil examples were to be told. The alternative to dubious novels and satirical romances were better, lofty romances: a production of romances modeled after Heliodorus arrived as a possible answer with excursions into the bucolic world. Honoré d'Urfés L'Astrée (1607-27) became the most famous work of this type. The criticism that these romances had nothing to do with real life was answered through the device of the roman à clef (literally "novel with a key", one that, properly understood, alludes to characters in the real world). John Barclay's Argenis (1625-26) appeared as a political roman à clef. The romances of Madeleine de Scudéry gained greater influence with plots situated in the ancient world and content taken from life. The famous author told stories of her friends in the literary circles of Paris and developed their fates from volume to volume of her serialised production. Readers of taste bought her books, as they offered the finest observation of human motives, characters taken from life, excellent morals regarding how one should and should not behave if one wanted to succeed in public life and in the intimate circles she portrayed. The novel went its own way: Paul Scarron (himself a hero in the romances of Madeleine de Scudéry) published the first volume of his Roman Comique in 1651 (successive volumes appeared in 1657 and, by another hand, in 1663) with a plea for the development Cervantes had induced in Spain. France should (as he wrote in the famous 21st chapter of his Roman Comique [http://www.pierre-marteau.com/library/e-1700-0002.html#c21]) imitate the Spanish with little stories like those they called "novels". Scarron himself added numerous of such stories to his own work. Twenty years later Madame de La Fayette made the next decisive steps with her two novels. The first, her Zayde published in 1670 together with Pierre Daniel Huet's famous Treatise on the Origin of Romances, was a "Spanish History". Her second and more important novel appeared in 1678: La Princesse de Clèves proved that France could actually produce novels of a particularly French taste. The Spanish enjoyed stories of proud Spaniards who fought duels to avenge their reputations. The French had a more refined taste with minute observation of human motives and behaviour. The story was firmly a "novel" and not a "romance": a story of unparalleled female virtue, with a heroine who had had the chance to risk an illicit amour and not only withstood the temptation but made herself more unhappy by confessing her feelings to her husband. The gloom her story created was entirely new and sensational. The regular novel took another turn. The late 17th century saw the emergence of a European market for scandal, with French books appearing now mostly in the Netherlands (where censorship was liberal) to be re-imported clandestinely back into France. The same production reached the neighbouring markets of Germany and Britain, where it was welcomed both for its French style and its predominantly anti-French politics. The novel flourished on this market as the best genre to purport scandalous news. The authors claimed the stories they had to tell were true, told not for the sake of scandal but only for the moral lessons they gave. To prove this, they fictionalized the names of their characters and told these stories as if they were novels. (The audience played its own game in identifying who was who). Journals of little stories appeared—the Mercure Gallant became the most important. Collections of letters added to the market; these included more of these little stories and led to the development of the epistolary novel in the late 17th century. In the late 1670s the novel reached the English market. Aphra Behn and William Congreve were among the first modern English authors to adopt the term.

State of Affairs: The Market around 1700

Early 18th century novels and romances were still not considered part the world of learning, hence, not of part of literature; they were market goods. If you opened the term catalogues it was mostly situated in the—predominantly political—field of "History and Politicks" with some romances like Cervantes Don Quixote translated into verse becoming poetical. The integration of prose fiction into the market of histories appeared under the following scheme:

image positioning

		3.1 Heroical Romances: Fénelon's Telemach (1699)
1 Sold as romantic inventions, read as true histories of public affairs: Manley's New Atalantis (1709)	2 Sold as romantic inventions, read as true histories of private affairs: Menantes' Satyrischer Roman (1706)	3.2 Classics of the novel from the Arabian Nights to M. de La Fayette's Princesse de Cleves (1678)	4 Sold as true private history, risking to be read as romantic invention: Defoe's Robinson Crusoe (1719)	5 Sold as true public history, risking to be read as romantic invention: La Guerre d'Espagne (1707)
		3.3 Satirical Romances: Cervantes' Don Quixote (1605)	From Olaf Simons, Marteaus Europa (Amsterdam, 2001), p.194.

The centre of the market was held by fictions which claimed to be fictions and which were read as such. They comprised a high production of romances and, at the bottom end, an opposing production of satirical romances. In the centre, the novel had grown, with stories that were neither heroic nor predominantly satirical, yet mostly realistic, short and stimulating with their examples of human actions to be discussed. The central production had two wings: On the left hand, one had books which claimed to be romances, but which threatened to be anything but fictitious. Delarivier Manley wrote the most famous of them, her New Atalantis, full of stories the author claimed to have invented. The censors were helpless: Manley had hawked stories discrediting the ruling Whigs, yet should they ask the Whigs to prove that all these stories actually happened on British soil rather than on the fairy tale island Atalantis? This was what they had to do if they wanted to sue the author. Delarivier Manley escaped the interrogations unscathed and continued her libellous work with three more volumes of the same ilk. Private stories appeared on the same market, creating a different genre of personal love and public battles over lost reputations. On the other hand one had a market of titles which claimed to be strictly non-fictional—Daniel Defoe's Robinson Crusoe became the most important of them. The genre-identification: "Sold as true private history, risking to be read as romantic invention" opened the preface:

IF ever the Story of any Man's Adventures in the World were worth making Publick, and were acceptable when Publish'd, the Editor of this Account thinks this will be so.
     The Wonders of this Man's Life exceed all that (he thinks) is to be found extant; the Life of one Man being scarce capable of a greater Variety.
     The Story is told with Modesty, with Seriousness, and with a religious Application of Events to the Uses to which wise Men always apply them (viz.) to the Instruction of others by this Example, and to justify and honor the Wisdom of Providence in all the Variety of Circumstances, let them happen how they will.
     The Editor believes the thing to be a just History of Fact; neither is there any Appearance of Fiction in it: And however thinks, because all such things are dispatch'd, that the Improvement of it, as well as the Diversion, as to the Instruction of the Reader, will be the same; and as such he thinks, without farther Compliment to the World, he does them a great Service in the Publication.

A production of histories of similar verisimilitude dove into the overtly political. Gatien de Courtilz de Sandras (1644-1712) became the most important author in this field with his first version of d'Artagnan's story, told again more than a century later by Alexandre Dumas the elder. Witty, and a distant precursor of Ian Fleming's fictional James Bond, is another book allegedly by his hand: La Guerre d'Espagne (1707) the story of a disillusioned French spy, who gave insight into French politics—and into his own love affairs, with little intrigues he managed wherever he had to do his jobs. Fact and fiction were mixed in all these titles, to

Spacecraft

Overview

Examples of past or existing spacecraft

Spacecraft under development

See also

External links

Vehicle

Types of vehicles

External Links

Unmanned space missions

See also

External links

Manned space missions

See also

External links

Satellite

Artificial satellites

History of artificial satellites

Types of satellites

Orbit types

Countries with satellite launch capability

See also

Reference

External links

Space suit

Spacesuit requirements

Theories of Spacesuit Design

Contributing technologies

Spacesuit models of historical significance

Spacesuits in fiction

See also

External links

Vacuum

Vacuum ranges

Perfect vacuum

Partial vacuum

Degrees of vacuum

Creating a vacuum

High vacuum

Ultra-high vacuum

Vacuum in space

The quantum-mechanical vacuum

Historical interpretation

See also

External links

Short story

History

Modern short stories

Elements and characteristics

Length

Genres

See also

Examples of classic short stories

Other resources

Novel

Novel/Romance: Unstable Words

History

Traditions of Prose Fiction: The Ancient World

The Romance, 1100-1500

The Emergence of the Novel, 1200-1500

The First Rise of the Novel, 1500-1750

State of Affairs: The Market around 1700