A
space habitat (also called an
orbital colony, or a
space colony,
city, or
settlement) is a
space stationA space station is an artificial structure designed for humans to live in outer space. To date, only low earth orbital stations have been implemented, otherwise known as orbital stations...
intended as a
permanent settlementSpace colonization is the concept of autonomous human habitation of locations outside Earth....
rather than as a simple waystation or other specialized facility. No space habitats have yet been constructed, but many design proposals have been made with varying degrees of realism by both
science fictionScience fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...
authors and
engineerEngineers are concerned with developing economical and safe solutions to practical problems, by applying mathematics and scientific knowledge while considering technical constraints. The term is derived from the Latin root "ingenium," meaning "cleverness"...
s.
History
About 1970, near the end of
Project ApolloNASA's Apollo Program landed the first humans on Earth's moon. US President John F. Kennedy announced his support for a manned moon landing on May 25, 1961, as part of a special address to a joint session of Congress:...
, 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) in diameter 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
NASAThe National Aeronautics and Space Administration is an agency of the United States government, responsible for the nation's public space program. NASA was established by the National Aeronautics and Space Act on July 29, 1958, replacing its predecessor, the National Advisory Committee for...
to sponsor a couple of summer workshops led by Dr. O'Neill. 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
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
s contain significant amounts of volatiles such as water and ammonia. This suggests 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. 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 effect of this expansion was the founding of the
L5 SocietyThe L5 Society was founded in 1975 by Carolyn and Keith Henson to promote the space colony ideas of Dr. Gerard K. O'Neill.The name comes from the and Lagrangian points in the Earth-Moon system proposed as locations for the huge rotating space habitats that Dr. O'Neill envisioned...
in the U.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.
In this era, Dr. O'Neill also founded the quieter, and more targeted
Space Studies InstituteSpace Studies Institute is a non-profit organization that was founded in 1977 by the late Princeton University Professor Dr. Gerard K. O'Neill. The stated mission is to "open the energy and material resources of space for human benefit within our lifetime"...
, 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. One of the early projects, for instance, was a series of functional prototypes of a
mass driverA mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch that would use a linear motor to accelerate and catapult payloads up to high speeds. All existing and contemplated mass drivers use coils of wire energized by electricity to make electromagnets. Sequential...
, the essential technology to be used to economically move ores from the moon to space colony orbits.
In 1986, the L5 Society later became the
National Space SocietyThe National Space Society is an international nonprofit 501, educational, and scientific organization specializing in space advocacy. NSS is a member of the Independent Charities of America, and an annual participant in the Combined Federal Campaign.The National Space Society's vision is people...
, and former members started a number of related efforts, including the
Artemis ProjectThe Moon Society is a space advocacy organization, founded in 2000, and dedicated to promoting large-scale human exploration, research, and settlement of the Moon.The objectives of the Society are:...
, and the
Mars SocietyThe Mars Society is an international space advocacy non-profit organization dedicated to encouraging the exploration and settlement of Mars. Founded by Robert Zubrin and others in mid-1998 and attracting the support of notable science fiction writers and filmmakers , the organization is dedicated...
. As well, some former L5 Society members seem to be active in radical engineering groups such as the
Extropian InstituteExtropianism, 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 FictionScience fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...
. Some of the most popular and recognizable are the Japanese
Gundamis a metaseries of Japanese anime created by Sunrise studios that features giant robots called "Gundam". The metaseries started in 7 April 1979 as a serial TV show called Mobile Suit Gundam. That first TV series has since spawned a franchise that has come to include works released in numerous media...
universe, and
Babylon 5Babylon 5 is an American science fiction television series created, produced and largely written by J. Michael Straczynski. The show centers on the Babylon 5 space station: a focal point for politics, diplomacy, and conflict during the years 2257–2262...
.
Motivation
There are several prominent reasons for
space colonizationSpace colonization is the concept of autonomous human habitation of locations outside Earth....
: security, profits, energy and raw materials.
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 survivalSpace and survival is the relationship between outer space and the long-term survival of the human species and civilization. It is based on the observation that space colonization and space science could prevent many human extinction scenarios...
)
Space has most of the same raw materials found on Earth, and large amounts of energy. It should be possible to make profits, if the infrastructure for space mining and
space manufacturingSpace manufacturing is the production of manufactured goods in an environment outside a planetary atmosphere. Typically this includes conditions of microgravity and hard vacuum.Manufacturing in space has several potential advantages over Earth-based industry....
can be created. The initial investments required are large, but the profitability is potentially open-ended.
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
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
can be viewed as quite small, overpopulated and restrictive compared to
outer spaceOuter space comprises the relatively empty regions of the universe outside the atmospheres of celestial bodies. Outer space is used to distinguish it from airspace and terrestrial locations....
.
Habitats outside the shadows of planets can use
solar powerSolar energy, radiant light and heat from the Sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...
24 hours a day. 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 powerNuclear power is power produced from controlled nuclear reactions. Commercial plants in use to date use nuclear fission reactions....
, which wouldn't have all the same environmental and safety concerns that might be present with a nuclear installation on Earth.
Advantages
Space habitats orbiting Earth have a number of potential advantages over those on the surface of other planets:
- Adjustable artificial gravity
Artificial gravity is a simulation of gravity in outer space or free-fall. Artificial gravity is desirable for long-term space travel or habitation, for ease of mobility and to avoid the adverse health effects of weightlessness.-Rotation:...
, via changing a colony's rotation speed. 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 MoonThe Moon is Earth's only natural satellite and the fifth largest satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is , about thirty times the diameter of the Earth. The common centre of mass of the system is located at about —a quarter the Earth's...
or MarsMars is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance, due to iron oxide prevalent on its surface....
) could result in insufficient skeletal strength to function effectively in Earth's higher gravity without significant habilitation.
- Access to vast resources, including the material of the solar system's asteroids (see Asteroid mining
Asteroid mining refers to the hypothetical exploitation of raw materials in deep space on asteroids and planetoids, usually in the Solar System. Minerals and other resources could be mined from an asteroid in space using a variety of methods...
).
- Constant access to solar energy.
- Immense population capacity. Using the free-floating resources of the solar system, current estimates extend into the trillions.
- Earth to space habitat trade would be easier than Earth to planetary colony trade, 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:
Initial capital outlay
Even the smallest of the habitat designs mentioned below is more massive than the total mass of all items ever launched by mankind into earth orbit. Prerequisites to building habitats are either cheaper launch costs or a mining and manufacturing base on the Moon or other body having low
delta-vIn astrodynamics, the term delta-v, literally "change in velocity" , has a specific meaning: it is a scalar which takes units of speed that measures the amount of "effort" needed to carry out an orbital maneuver, i.e., to change from one trajectory to another.Where is the instantaneous thrust is...
from the desired station orbit.
Internal life support systems
Air
pressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
with normal partial pressures of
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
,
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
and
nitrogenNitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere.Many industrially important...
is a basic requirement of any space habitat. Basically, most colony designs are large, thin-walled pressure vessels. Oxygen is available from lunar rock. Nitrogen is available from the Earth 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 air can be recycled in a number of ways. The obvious method is to use
photosyntheticPhotosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of Bacteria, but not in Archaea...
gardenGardening is the practice of growing ornamental or useful plants. Ornamental plants are normally grown for their flowers, foliage, or overall appearance. Useful plants may be grown for consumption or for a variety of other purposes, such as medicines or dyes...
s, possibly using
hydroponicsHydroponics is a method of growing plants using mineral nutrient solutions, in water, without soil...
or
forest gardeningForest gardening is a food production and land management system based on replicating woodland ecosystems, but substituting trees , bushes, shrubs, herbs and vegetables which have yields directly useful to humans...
. 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. Further protection might be provided by a small cryogenic distillation system to gradually remove impurities such as
mercuryMercury , also called quicksilver or hydrargyrum , is a chemical element with the symbol Hg and atomic number 80...
vapor, and noble gases that cannot be catalytically burned.
OrganicOrganic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...
materials for food production must also be provided. 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. 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.
Simulated gravity
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
inertiaInertia is the resistance of any physical object, to a change in its state of motion. It is represented numerically by an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to describe the motion of matter and how it is affected by...
l forces to
simulate gravityArtificial gravity is a simulation of gravity in outer space or free-fall. Artificial gravity is desirable for long-term space travel or habitation, for ease of mobility and to avoid the adverse health effects of weightlessness.-Rotation:...
. 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 to 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 ray
Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, almost 10% are helium nuclei , and slightly under 1% are heavier elements and electrons...
s 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. Another, separate issue is that solar flareA solar flare is a large explosion in the Sun's atmosphere that can release as much as 6 × 10
25 joules of energy. The term is also used to refer to similar phenomena in other stars, where the more accurate term stellar flare applies....
s occasionally emit very large amounts of soft x-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays...
s, and energetic particles. When these events occur, they can exceed 4 sievertThe sievert is the SI derived unit of dose equivalent. It attempts to reflect the biological effects of radiation as opposed to the physical aspects, which are characterised by the absorbed dose, measured in gray...
s, the lethal dose for half the population. The most interesting result of the studies was the discovery that large space habitats are effectively shieldedGamma rays are electromagnetic radiation of high frequency . They are produced by sub-atomic particle interactions, such as electron-positron annihilation, neutral pion decay, radioactive decay, fusion, fission or inverse Compton scattering in astrophysical processes...
by their structure and air, which easily exceeds the two meters of steel needed. 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 periscopeA periscope is an instrument for observation from a concealed position. In its simplest form, it is a tube in each end of which are mirrors set parallel to each other at 45 degree angle....
.
- 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
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...
to eliminate heat from absorbed sunlight and organisms. Very small habitats might have a central vane that rotates with the colony. In this design, convectionConvection is the movement of molecules within fluids . Convection is one of the major modes of heat transfer and mass transfer...
would raise hot air "up" (toward the center), and cool air would fall down into the outer habitat. 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
Space debris, also known as orbital debris, space junk and space waste, are objects in orbit around Earth created by humans that no longer serve any useful purpose...
, meteoroids, dust etc.
Transportation and maneuvering
- Orbital stationkeeping: The optimal habitat orbits are still debated, and so 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, either low earth orbit , or geostationary orbit...
is probably a commercial issue. The lunar and 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 propulsionTether propulsion systems are proposals to use long, very strong cables to change the velocity of spacecraft. The tethers may be used to initiate launch, complete launch, or alter the orbit of a spacecraft...
, or mass driverA mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch that would use a linear motor to accelerate and catapult payloads up to high speeds. All existing and contemplated mass drivers use coils of wire energized by electricity to make electromagnets. Sequential...
s used as rocket motors. The advantage of these is that they either use no reaction mass at all, or use cheap reaction mass.
- Attitude control: Most mirror geometries require something on the habitat to be aimed at the sun and so attitude control is necessary. The original O'Neill design used the two cylinders as momentum wheel
A reaction wheel is a type of flywheel used primarily by spacecraft to change their angular momentum without using fuel for rockets or other reaction devices....
s to roll the colony, and pushed the sunward pivots together or apart to use precessionPrecession refers to a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
to change their angle. 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.
NASA designs
Designs proposed in NASA studies included:
- Bernal sphere
A Bernal sphere is a type of space habitat intended as a long-term home for permanent residents, first proposed in 1929 by John Desmond Bernal....
- "Island One", a spherical habitat for about 20,000 people.
- Stanford torus
The Stanford torus is a proposed design for a space habitat capable of housing 10,000 to 140,000 permanent residents.The Stanford Torus was proposed during the 1975 NASA Summer Study, conducted at Stanford University, with the purpose of speculating on designs for future space colonies...
- A larger alternative to "Island One."
- O'Neill cylinder - "Island Three" (pictured), the largest design.
- Lewis One A cylinder of radius 250m with a non rotating radiation shielding. The shielding protects the micro-gravity industrial space, too. The rotating part is 450 long and has several inner cylinders. Some of them are used for agriculture.
- Kalpana One, revisedA short cylinder with 250 m radius and 325 m length. The radiation shielding is 10 t/m2 and rotates. It has several inner cylinders for agriculture and recreaction.
- A "bolo," a spacecraft or habitat connected by a cable to a counterweight
A counterweight is an equivalent counterbalancing weight that balances a load.-Uses:A counterweight is often used in traction lifts , cranes and funfair rides...
or other habitat. This design has been proposed as a Mars ship, initial construction shack for a space habitat, and orbital hotelTranshab was a concept pursued by NASA to develop the technology for expandable habitats inflated by air in space. Specifically, Transhab was intended as a replacement for the already existing rigid International Space Station crew Habitation Module. When deflated, inflatable modules provide an...
. It has a comfortably long and slow rotational radius for a relatively small station mass. Also, if some of the equipment can form the counter-weight, the equipment dedicated to artificial gravity is just a cable, and thus has a much smaller mass-fraction than in other designs. This makes it a tempting design for a deep-space ship. For a long-term habitation, however, radiation shielding must rotate with the habitat, and is extremely heavy, thus requiring a much stronger and heavier cable.
- "Beaded habitats"; this speculative design was also considered by the NASA studies, and found to have a roughly equivalent mass fraction of structure and therefore comparable costs. Small habitats would be mass-produced to standards that allow the habitats to interconnect. A single habitat can operate alone as a bolo. However, further habitats can be attached, to grow into a "dumbbell" then a "bow-tie," then a ring, then a cylinder of "beads," and finally a framed array of cylinders. Each stage of growth shares more radiation shielding and capital equipment, increasing redundancy and safety while reducing the cost per person. This design was originally proposed by a professional architect because it can grow much like Earth-bound cities, with incremental individual investments, unlike designs that require large start-up investments. The main disadvantage is that the smaller versions use a large amount of structure to support the radiation shielding, which rotates with them. In large sizes, the shielding becomes economical, because it grows roughly as the square of the colony radius. The number of people, their habitats and the radiators to cool them grow roughly as the cube of the colony radius.
Other designs
- Bubbleworld; The Bubbleworld, or Inside/Outside concept, was originated in 1964 by Dandridge M. Cole
Dandridge MacFarlan Cole was an American aerospace engineer, futurist, lecturer, and author.-Parents and Education:Cole was born February 19, 1921 in Sandusky, Ohio to Robert MacFarlan Cole III and Wertha Pendleton Cole, the daughter of bishop William Frederic Pendleton.He attended the Academy of...
and Donald W. Cox in a nonfiction book called Islands in Space: The Challenge of the Planetoids.
The concept calls for a large asteroid of iron or nickel-iron composition to have a tunnel drilled through its longest axis of rotation and filled with a volatileVolatility in the context of chemistry, physics and thermodynamics is a measure of the tendency of a substance to vaporize. It has also been defined as a measure of how readily a substance vaporizes...
substance, possibly water. A very large solar reflector would be constructed nearby, focusing solar heat onto the asteroid, first to weld and seal the tunnel ends, then more diffusely to slowly heat the entire outer surface. As the metal softens, the water inside expands and inflates the mass, while rotational forces help shape it into a cylindrical form. Once expanded and allowed to cool, it can be spun to produce artificial gravity, and the interior filled with soil, air and water. By creating a slight bulge in the middle of the cylinder, a ring-shaped lake can be made to form. Reflectors will allow sunlight to enter and to be directed where needed. Clearly, this method would require a significant human and industrial presence in space to be at all feasible.
The Bubbleworld concept was popularized by science fictionScience fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...
author Larry NivenLaurence van Cott Niven is a US science fiction author. Perhaps his best-known work is Ringworld , which received Hugo, Locus, Ditmar, and Nebula awards. His work is primarily hard science fiction, using big science concepts and theoretical physics. It also often includes elements of detective...
. Niven used the idea in his fictional Known SpaceKnown Space is the fictional setting of several science fiction novels and short stories written by author Larry Niven. It has also in part been used as a shared universe in the Man-Kzin Wars spin-off anthologies sub-series....
stories, describing these worlds as the primary habitats of the BeltersIn Larry Niven's fictional Known Space universe, a Belter refers to a resident of the Asteroid Belt around Sol, sometimes known as the Sol Belt to differentiate it from Alpha Centauri's Serpent Swarm....
, a civilization who had colonized the Asteroid BeltThe asteroids have long been suggested as possible sites for human colonization. This idea is popular in science fiction. Asteroid mining, a proposed industrial process in which asteroids are mined for valuable materials, especially platinum group metals, may be automated or require a crew to...
.
External links
See also
- Space manufacturing
Space manufacturing is the production of manufactured goods in an environment outside a planetary atmosphere. Typically this includes conditions of microgravity and hard vacuum.Manufacturing in space has several potential advantages over Earth-based industry....
- Transhab
Transhab was a concept pursued by NASA to develop the technology for expandable habitats inflated by air in space. Specifically, Transhab was intended as a replacement for the already existing rigid International Space Station crew Habitation Module. When deflated, inflatable modules provide an...
- Inflatable space habitat
Inflatable habitats are pressurised modules for use in an outer space environment to support human life. They have frequently been proposed for use in space applications to provide a greater volume of living space for a given mass....
- Space station
A space station is an artificial structure designed for humans to live in outer space. To date, only low earth orbital stations have been implemented, otherwise known as orbital stations...
- Generation ship
A generation ship is a hypothetical type of interstellar ark starship that travels across great distances between stars at a speed much slower than that of light...
- Space weather
Space weather is the concept of changing environmental conditions in near-Earth space. It is distinct from the concept of weather within a planetary atmosphere, and deals with phenomena involving ambient plasma, magnetic fields, radiation and other matter in space...
- The Brick Moon
"The Brick Moon" is a short story by Edward Everett Hale, published serially in The Atlantic Monthly starting in 1869. It is a work of speculative fiction containing the first known depiction of an artificial satellite.- Synopsis :...