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A pair of O'Neill cylinders
A pair of O'Neill cylinders
Interior of a torus station
Interior of a torus station

A space habitat, also called space colony, orbital colony, space city, or space settlement is a space station intended as a permanent settlement rather than as a simple waystation or other specialized facility. In Geometry, a torus (pl tori) is a Surface of revolution generated by revolving a Circle in three dimensional space about an axis Coplanar A space station is an artificial structure designed for Humans to live in Outer space. Space colonization (also called space settlement, space humanization, Space habitation, etc No space habitats have yet been constructed beyond Earth orbit, but many design proposals have been made with varying degrees of realism by both science fiction authors and engineers. An engineer is a person professionally engaged in a field of Engineering.

Contents

History

About 1970, near the end of Project Apollo, Gerard K. O'Neill, an experimental physicist, was looking for a topic to tempt his physics students, most of whom were freshmen in Engineering. He hit upon the creative idea of assigning them feasibility calculations for large space habitats. To his surprise, the habitats seemed to be feasible even in very large sizes: cylinders five miles (8 km) wide and twenty miles (34 km) long, even if made from ordinary materials such as steel and glass. Also, the students solved problems such as radiation protection from cosmic rays (almost free in the larger sizes), getting naturalistic sun angles, provision of power, realistic pest-free farming and orbital attitude control without reaction motors. He published an article about these colony proposals in Physics Today in 1974. (See the above illustration of such a colony, a classic "O'Neill Colony"). The article was expanded in the book High Frontier.

The result motivated NASA to sponsor a couple of summer workshops led by Dr. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program O'Neill. [1][2] Several designs were studied, some in depth, with sizes ranging from 1,000 to 10,000,000 people. Attempts were made to make the habitats as self-supporting as possible, but all of the designs relied on regular shipments from Earth or the Moon, notably for raw materials and volatiles. Closed ecologies and aggressive recycling should dramatically reduce this reliance. Recent research has increased the probability of finding frozen water in deep craters on the moon's south pole, and found that certain asteroids contain significant amounts of volatiles such as water and ammonia. Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but Therefore, space habitats could rely less on Earth than these original studies indicated.

At the time, colonization was definitely seen as an end in itself. The basic proposal by O'Neill had an example of a payback scheme: construction of solar power satellites from lunar materials. A solar power satellite, or SPS or Powersat, as originally proposed would be a Satellite built in High Earth orbit that uses Microwave O'Neill's intention was not to build solar power satellites as such, but rather to give an existence proof that orbital manufacturing from lunar materials could generate profits. He, and other participants, presumed that once such manufacturing facilities were on-line, many profitable uses for them would be found, and the colony would become self-supporting, and begin to build other colonies as well.

The proposals and studies generated a notable groundswell of public interest. One of the most interesting public effects was the founding of the L5 Society in the U. The L5 Society was founded in 1975 by Carolyn and Keith Henson to promote the space colony ideas of Dr S. , a group of enthusiasts that desired to build and live in such colonies. The group was named after the space-colony orbit which was then believed to be the most profitable, a kidney-shaped orbit around either of Earth's lunar Lagrange points 5 or 4.

Interior view of the Rama O'Neill Cylinder Mobile Wordlet from Arthur C. Clarke's Rendezvous with Rama series
Interior view of the Rama O'Neill Cylinder Mobile Wordlet from Arthur C. Clarke's Rendezvous with Rama series

In this era, Dr. Sir Arthur Charles Clarke, CBE (16 December 1917–19 March 2008 was a British Science fiction Author, Inventor, and Rendezvous with Rama is a novel by Arthur C Clarke first published in 1972. O'Neill also founded the quieter, and more targeted Space Studies Institute, which initially funded and constructed prototypes of much of the radically new hardware needed for a space colonization effort, as well as number of paper studies of feasibility. Space Studies Institute is a non-profit organization that was founded in 1977 by the late Princeton University Professor Dr One of the early projects, for instance, was a series of functional prototypes of a mass driver, the essential technology to be used to economically move ores from the moon to space colony orbits. A mass driver or electromagnetic Catapult is a method of Non-rocket spacelaunch that would use a Linear motor to Accelerate

In 1986, the L5 Society later became the National Space Society, and former members started a number of related efforts, including the Artemis Project, and the Mars Society. The National Space Society (NSS is an international nonprofit 501(c(3, educational and scientific organization specializing in Space advocacy. The Moon Society is a Space advocacy organization founded in 2000, and dedicated to promoting large-scale human exploration research and settlement The Mars Society is an international Space advocacy Non-profit organization dedicated to encouraging the exploration and settlement of Mars. As well, some former L5 Society members seem to be active in radical engineering groups such as the Extropian Institute. Extropianism, also referred to as extropism or Extropy, is an evolving framework of values and standards for continuously improving the human condition A number of prominent modern space engineers and rocket scientists trace their motivation to this era.

The space habitats have inspired a large number of fictional societies in Science Fiction. Some of the most popular and recognizable are the Japanese Gundam universe, and Babylon 5. is a Metaseries of English Anime, featuring tiny robots or " Kounans " created by Sunrise studios Babylon 5 is an American science fiction television series created produced and largely written by J

Motivation

There are several prominent reasons for space colonization: security, profits, energy and raw materials. Space colonization (also called space settlement, space humanization, Space habitation, etc

Space habitats are likely to be less affected by disasters that damage the Earth, such as overpopulation, or ocean strikes by large bolides (e. g. meteorites, etc). Although an individual habitat is probably less secure than Earth, many habitats together add substantially to human survivability. They provide opportunities for migration. (See: Space and survival)

Space has most of the same raw materials found on Earth, and large amounts of energy. Space and survival is the relationship between Outer space and the long-term Survival of the Human species and Civilization. It should be possible to make profits, if the infrastructure for space mining and space manufacturing can be created. Space mining refers to the future practice of Mining Asteroids Meteoroids the Moon and Planets - any Astronomical object Space manufacturing is the production of Manufactured goods in an environment outside a Planetary atmosphere. The initial investments required are large, but the profitability is potentially open-ended.

For example, some proponents estimate that compared to Earth, a family or company might easily triple or quadruple their incomes. Costs might be lower as well. Proponents' estimates of the cost of space colony land work out to roughly $30,000 per acre ($7. 50/m²) in 1995 USD, in large economical space colonies. M^2 redirects here For other uses see M². CM2 redirects here The United States dollar ( sign: $; code: USD) is the unit of Currency of the United States; it has also been While expensive for rural land, it is inexpensive for city land.

As there exists a vast amount of material to build with in the solar system, and as a space habitat is out of planetary gravity wells, allowing for relatively cheap travel and movement of materials, a vast population using multiple habitats could live and work in space permanently. The Earth can be viewed as quite small, overpopulated and restrictive compared to outer space. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Outer space, often simply called space, comprises the relatively empty regions of the Universe outside the escape velocities of Celestial bodies.

Habitats outside the shadows of planets can use solar power 24 hours a day. Solar energy is the Light and radiant heat from the Sun that powers Earth 's Climate and Weather and sustains Life Zero-g enables the creation of extremely large-yet-flimsy concentrating mirrors to gather this constant and abundant energy. As well, colonies may employ nuclear power, which wouldn't have all the same environmental and safety concerns that might be present with a nuclear installation on Earth. Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions

Advantages

Space habitats have a number of potential advantages over planet-based colonies:

  1. Adjustable artificial gravity, via changing a colony's rotation speed. Artificial gravity is a simulation of gravity in Outer space or Free-fall. This attribute is important if humans born and raised on the colonies are to be able to return to Earth. It is expected that those born on low-gravity bodies (such as the Moon or Mars) could result in insufficient skeletal strength to function effectively in Earth's higher gravity without significant habilitation. In Biology, the skeleton is a strong and often a rigid framework that supports the body of an animal holding it upright and giving it shape and strength (Also skeletal
  2. Access to vast resources, including the material of the solar system's asteroids (see Asteroid mining). Raw resources and minerals could be mined from an Asteroid in space using a variety of methods
  3. Constant access to solar energy. Solar energy is the Light and radiant heat from the Sun that powers Earth 's Climate and Weather and sustains Life
  4. Immense population capacity. Using the free-floating resources of the solar system, current estimates extend into the trillions. [3]
  5. Easier trade with Earth than planetary colonies, as colonies orbiting Earth will not have a gravity well to overcome to export to Earth, and a smaller gravity well to overcome to import from Earth.

Problems

Space habitats must solve a number of problems in order to maintain healthy normal human populations:

Internal life support systems

Air pressure with normal partial pressures of oxygen, carbon dioxide and nitrogen is a basic requirement of any space habitat. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Basically, most colony designs are large, thin-walled pressure vessels. Oxygen is available from lunar rock. Nitrogen is available from the Earth, an expensive source, but nitrogen is recycled nearly perfectly. Also, nitrogen may be available from comets and outer planets' moons in the form of ammonia. Nitrogen may also be available in unknown quantities on certain other bodies in the outer solar system. The Solar System consists of the Sun and those celestial objects bound to it by Gravity. The air can be recycled in a number of ways. The obvious method is to use photosynthetic gardens, possibly using hydroponics or forest gardening. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Gardening is the practice of growing Plants for their attractive flowers or foliage and Vegetables or Fruits for consumption Hydroponics (from the Greek words hydro (water and ponos (labour is a method of growing Plants using mineral Nutrient solutions without Forest gardening (also known as 3-Dimensional Gardening is a Food production and Land management system based on replicating Woodland Ecosystems However, these do not remove some industrial pollutants, such as volatile oils, and excess simple molecular gases. The standard method used on nuclear submarines is to use a catalytic burner, which effectively removes most organics. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Further protection might be provided by a small cryogenic distillation system to gradually remove impurities such as mercury vapor, and noble gases that cannot be catalytically burned. Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum

Organic materials for food production must also be provided. Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation At first, most of these would have to be imported from the moon, asteroids, or the Earth. After that, recycling would reduce the need for imports. One proposed recycling method would start by burning the cryogenic distillate, plants, garbage and sewage with air in an electric arc, and distilling the result. The resulting carbon dioxide and water would be immediately usable in the farms. The nitrates and the salts in the ash would be dissolved in water and separated into pure minerals. Most of the nitrates, potassium and sodium salts would effectively recycle as fertilizers. Other minerals containing iron, nickel, and silicon could be chemically purified in batches and reused industrially. The small fraction of remaining materials, well below 0. 01% by weight, could be processed into pure elements with zero-gravity mass spectrography, and added in appropriate amounts to the fertilizers and industrial stocks. Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles This method's only current existence is a proof considered by NASA studies. It's likely that methods would be greatly refined as people begin to actually live in space habitats.

Artificial gravity. Artificial gravity is a simulation of gravity in Outer space or Free-fall. Long-term on-orbit studies have proven that zero gravity weakens bones and muscles, and upsets calcium metabolism and immune systems. Most people have a continual stuffy nose or sinus problems, and a few people have dramatic, incurable motion sickness. Most colony designs would rotate in order to use inertial forces to simulate gravity. The vis insita or innate force of matter is a power of resisting by which every body as much as in it lies endeavors to preserve in its present state whether it be of rest or of moving Artificial gravity is a simulation of gravity in Outer space or Free-fall. NASA studies with chickens and plants have proven that this is an effective physiological substitute for gravity. Turning one's head rapidly in such an environment causes a "tilt" to be sensed as one's inner ears move at different rotational rates. Centrifuge studies show that people get motion-sick in habitats with a rotational radius of less than 100 metres, or with a rotation rate above 3 rotations per minute. However, the same studies and statistical inference indicate that almost all people should be able live comfortably in habitats with a rotational radius larger than 500 meters and below 1 RPM. Experienced persons were not merely more resistant to motion sickness, but could also use the effect to determine "spinward" and "antispinward" directions in the centrifuges.

Protection from hostile external environment

Radiation: Space radiation has two distinct problems. One is that cosmic rays expose one to 80 millisieverts per year, well above the maximum safe occupational threshold of 50 mSv, and well above the healthy population maximum of 3 mSv. For the 1962 Bruce Conner film see Cosmic Ray (film Cosmic rays are energetic particles originating from space that impinge on The sievert (symbol Sv is the SI derived unit of dose equivalent. Another, separate issue is that solar flares occasionally emit very large amounts of soft x-rays, and energetic particles. A solar flare is a violent explosion in a star's (like the Sun 's atmosphere releasing as much Energy as 6 × 1025 Joules Solar flares X-radiation (composed of X-rays) is a form of Electromagnetic radiation. When these events occur, they can exceed 4 sieverts, the lethal dose for half the population. The sievert (symbol Sv is the SI derived unit of dose equivalent. The most interesting result of the studies was the discovery that large space habitats are effectively shielded by their structure and air, which easily exceeds the two meters of steel needed. Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions Smaller habitats could be shielded by stationary (nonrotating) bags of rock. Sunlight could be admitted indirectly via mirrors in radiation-proof louvres, which would function in the same manner as a periscope. A periscope is an instrument for observation from a concealed position

Heat rejection: The colony is in a vacuum, and therefore resembles a giant thermos bottle. The sunlight to radiated energy ratio can be reduced and controlled with large venetian blinds. Habitats also need a radiator to eliminate heat from absorbed sunlight and organisms. Radiators and convectors are types of Heat exchangers designed to transfer Thermal energy from one medium to another for the purpose of cooling Very small habitats might have a central vane that rotates with the colony. In this design, convection would raise hot air "up" (toward the center), and cool air would fall down into the outer habitat. Convection in the most general terms refers to the movement of molecules within Fluids (i Some other designs would distribute coolants, such as chilled water from a central radiator. Because blinds and radiators might be a major expense, inexpensive habitats might be very warm.

Foreign objects: The habitat would need to withstand potential impacts from space debris, meteoroids, dust etc. Space debris or orbital debris, also called space junk and space waste are the objects in Orbit around Earth created by humans that no

Transportation and maneuvering

Orbital stationkeeping. In Astrodynamics orbital station-keeping is a term used to describe a particular set of Orbital maneuvers used to keep a spacecraft in assigned Orbit The optimal habitat orbits are still debated, and are probably a commercial issue. The lunar L4 and L5 orbits are now thought to be too far away from the moon and Earth. A more modern proposal is to use a two-to-one resonance orbit that alternately has a close, low-energy (cheap) approach to the moon, and then to the Earth. This provides quick, inexpensive access to both raw materials and the major market. Most colony designs plan to use electromagnetic tether propulsion, or mass drivers used as rocket motors. Tether propulsion systems are proposals to use long very strong cables (known as Tethers to change the velocity of Spacecraft. A mass driver or electromagnetic Catapult is a method of Non-rocket spacelaunch that would use a Linear motor to Accelerate The advantage of these is that they either use no reaction mass at all, or use cheap reaction mass.

Attitude control. The attitude of a body is its orientation as perceived in a certain Frame of reference; providing a vector along which a spacecraft is pointing is a description of its attitude Most mirror geometries require something on the habitat to be aimed at the sun. The original O'Neill design used the two cylinders as momentum wheels to roll the colony, and pushed the sunward pivots together or apart to use precession to change their angle. Precession refers to a change in the direction of the axis of a rotating object Later designs rotated in the plane of their orbit, with their windows pointing at right angles to the sunlight, and used lightweight mirrors that could be steered with small electric motors to follow the sun.

Designs (solutions)

NASA designs

Designs proposed in NASA studies included:

Other designs

References

  1. ^ Space Settlements: A Design Study (1975). Retrieved on 2006-12-18. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 218 BC - Second Punic War: Battle of the Trebia - Hannibal 's Carthaginian forces defeat those of the
  2. ^ Ames Summer Study on Space Settlements and Industrialization Using Nonterrestial Materials (1977). Retrieved on 2006-05-28. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling
  3. ^ O'Neill, Gerard K. The colonization of space, [1] (Physics Today, September 1974). Physics Today magazine created in 1948 is the membership journal of The American Institute of Physics. Year 1974 ( MCMLXXIV) was a Common year starting on Tuesday (link will display full calendar of the 1974 Gregorian calendar. Retrieved on 2006-10-15.
  4. ^ Globus, Al. Lewis One Space Colony. Retrieved on 2006-05-28. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling
  5. ^ Cole, Dandridge M. ; Cox, Donald W. (1964). Islands in space: The challenge of the planetoids.  

External links

See also


Space manufacturing is the production of Manufactured goods in an environment outside a Planetary atmosphere. Transhab was a concept pursued by NASA to develop the technology for expandable habitats inflated by air in space Inflatable habitats are pressurised modules for use in an Outer space environment to support Human life A space station is an artificial structure designed for Humans to live in Outer space. A generation ship is a hypothetical Starship that travels across great distances between stars at a speed much slower than that of light (see Interstellar travel Rendezvous with Rama is a novel by Arthur C Clarke first published in 1972. Space weather is the concept of changing environmental conditions in Outer space.
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