Orbital ring
Encyclopedia
Space elevator
A space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...
that consists of a ring in low earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
that rotates at above orbital speed, that has fixed tethers hanging down to the ground.
The structure is intended to be used for space launch
Space launch
Space launch is the earliest part of a flight that reaches space. Space launch involves liftoff, when a rocket or other space launch vehicle leaves the ground at the start of a flight...
.
The original orbital ring concept is related to the space fountain
Space fountain
A space fountain is a proposed form of space elevator that does not require the structure to be in geostationary orbit, and does not rely on tensile strength for support. In contrast to the original space elevator design , a space fountain is a tremendously tall tower extending up from the ground...
and launch loop
Launch loop
A launch loop or Lofstrom loop is a proposed system for launching objects into space orbit using a moving cable-like system attached to the earth at two ends and suspended above the atmosphere in the middle...
and was explored in detail by Paul Birch
Paul Birch (writer)
Paul Birch is a British author, engineer and scientist, who has worked in radioastronomy and satellite communications, and now writes full time.He is a former Fellow of the British Interplanetary Society....
and published in three parts in the Journal of the British Interplanetary Society
Journal of the British Interplanetary Society
The Journal of the British Interplanetary Society is a technical scientific journal, first published in 1934. JBIS is concerned with space science and space technology...
in 1982.
History
Arthur C. ClarkeArthur C. Clarke
Sir Arthur Charles Clarke, CBE, FRAS was a British science fiction author, inventor, and futurist, famous for his short stories and novels, among them 2001: A Space Odyssey, and as a host and commentator in the British television series Mysterious World. For many years, Robert A. Heinlein,...
published a book called The Fountains of Paradise
The Fountains of Paradise
The Fountains of Paradise is a Hugo and Nebula Award–winning 1979 novel by Arthur C. Clarke. Set in the 22nd century, it describes the construction of a space elevator. This "orbital tower" is a giant structure rising from the ground and linking with a satellite in geostationary orbit at the...
about space elevator
Space elevator
A space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...
s, but which in an appendix referred to an idea to launch things off the Earth using a structure based on mass drivers. The idea apparently did not work, but this inspired further research.
Paul Birch publishes a series of articles in the Journal of the British Interplanetary Society
Journal of the British Interplanetary Society
The Journal of the British Interplanetary Society is a technical scientific journal, first published in 1934. JBIS is concerned with space science and space technology...
(JBIS) in 1982.
Anatoly E. Yunitsky also published a similar idea in 1982.
Birch's model
In the simplest design of an orbital ring system, a rotating cable or possibly an Inflatable space structureInflatable space structures
Inflatable space structures are structures which use pressurized air to maintain shape and rigidity. Notable examples of terrestrial inflatable structures include inflatable boats, and some military tents. Inflatable structures are also candidates for space structures, given their low weight, and...
is placed in a low Earth orbit above the equator, rotating at faster than orbital speed. Not in orbit, but riding on this ring, supported electromagnetically on superconducting magnets, are ring stations that stay in one place above some designated point on Earth. Hanging down from these ring stations are short space elevators made from cables with high tensile strength to mass ratio materials.
Although this simple model would work best above the equator, Paul Birch found that since the ring station can be used to accelerate the orbital ring eastwards as well as hold the tether, it is therefore possible to deliberately cause the orbital ring to precess around the Earth instead of staying fixed in space while the Earth rotates beneath it. By precessing the ring once every 24 hours, the Orbital Ring will hover above any meridian selected on the surface of the Earth. The cables which dangle from the ring are now geostationary without having to reach geostationary altitude or without having to be placed into the equatorial plane. This means that using the Orbital Ring concept, one or many pairs of Stations can be positioned above any points on Earth desired or can be moved everywhere on the globe. Thus, any point on Earth can be served by a space elevator. Also a whole network of orbital rings can be built, which, by crossing over the poles, could cover the whole planet and be capable of taking over most of freight and passenger transport. By an array of elevators and several geostationary ring stations, asteroid or Moon material can be received and gently put down where land fills are needed. The electric energy generated in the process would pay for the system expansion and ultimately could pave the way for a solar-system-wide terraforming- and astroengineering-activity on a sound economical basis.
If built by launching the necessary materials from Earth, the estimated cost for the system in 1980s money was around $31 trillion if launched using Shuttle-derived hardware, whereas it could fall to $15 billion with bootstrapping, assuming a large orbital manufacturing facility is available to provide the initial 18,000 tonnes of steel, aluminium, and slag at a low cost, and even lower with orbital rings around the moon. The system's cost per kilogram to place payloads in orbit would be around $0.05.
Types of orbital rings
The simplest type would be a circular orbital ring in LEOLow Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
.
Two other types were also defined by Paul Birch:
- Eccentric orbital ring systems - these are rings that are in the form of a closed shape with varying altitude
- Partial orbital ring systems- this is essentially a Launch loopLaunch loopA launch loop or Lofstrom loop is a proposed system for launching objects into space orbit using a moving cable-like system attached to the earth at two ends and suspended above the atmosphere in the middle...
In addition, he proposed the concept of "supramundane worlds" such as supra-jovian and supra-stellar "planets". These are artificial planets that would be supported by a grid of orbital rings that would be positioned above a planet, supergiant or even a star.
Orbital rings in fiction
Donald KingsburyDonald Kingsbury
Donald MacDonald Kingsbury is an American–Canadian science fiction author. Kingsbury taught mathematics at McGill University, Montreal, from 1956 until his retirement in 1986.- Books :...
described a partial ring (a few hundred kilometers long) in his novel The Moon Goddess and the Son
The Moon Goddess and the Son
The Moon Goddess and the Son is a science fiction novel by American writer Donald Kingsbury, expanded from a novella originally published in the December 1979 issue of Analog magazine....
.
The manga Battle Angel Alita
Battle Angel Alita
Battle Angel Alita, known in Japan as , is a manga series created by Yukito Kishiro in 1990 and originally published in Shueisha's Business Jump magazine. Two of the nine-volume comics were adapted into two anime original video animation episodes titled Battle Angel for North American release by...
prominently features a slightly deteriorated orbital ring.
The second iteration of the anime
Anime
is the Japanese abbreviated pronunciation of "animation". The definition sometimes changes depending on the context. In English-speaking countries, the term most commonly refers to Japanese animated cartoons....
series Tekkaman
Tekkaman Blade
or Teknoman is an anime series, released in 1992 and 1995 in both Japanese and English language versions.-Plot:During the year 2300 AD , otherwise known as United Earth Year 192, the Earth is under attack from an extraterrestrial enemy known as the Radam...
features a complete ring, though abandoned and in disrepair due to war, and without surface tethers.
The anime
Anime
is the Japanese abbreviated pronunciation of "animation". The definition sometimes changes depending on the context. In English-speaking countries, the term most commonly refers to Japanese animated cartoons....
series Kiddy Grade
Kiddy Grade
is a 24 episode science fiction anime series produced in 2002 and created by gímik and Gonzo Digimation and directed by Keiji Gotoh. The series is licensed and distributed in North America by FUNimation Entertainment. The series currently airs on the FUNimation Channel in both its "syndicated...
also uses orbital rings as a launch and docking bay for spaceships. These rings are connected to large towers extending from the planets surface.
Orbital rings are used extensively in the collaborative fiction
Collaborative fiction
Collaborative fiction is a form of writing by a group of authors who share creative control of a story.Collaborative fiction can occur for commercial gain, as part of education, or recreationally - many collaboratively written works have been the subject of a large degree of academic research.-...
worldbuilding website Orion's Arm
Orion's Arm
Orion's Arm, is a multi-authored online science fiction world-building project, first established in 2000 by M. Alan Kazlev, Donna Malcolm Hirsekorn, Bernd Helfert and Anders Sandberg and further co-authored by many people since...
.
Arthur C. Clarke's 3001: The Final Odyssey
3001: The Final Odyssey
3001: The Final Odyssey is a science fiction novel by Sir Arthur C. Clarke. It is the fourth and final book in Clarke's Space Odyssey series.-Plot summary:...
features an orbital ring with differing levels of gravity, provided by the centripetal force of the ring's spinning.
See also
- Space elevatorSpace elevatorA space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...
- Space fountainSpace fountainA space fountain is a proposed form of space elevator that does not require the structure to be in geostationary orbit, and does not rely on tensile strength for support. In contrast to the original space elevator design , a space fountain is a tremendously tall tower extending up from the ground...
- Launch loopLaunch loopA launch loop or Lofstrom loop is a proposed system for launching objects into space orbit using a moving cable-like system attached to the earth at two ends and suspended above the atmosphere in the middle...
- Megascale engineeringMegascale engineeringMegascale engineering is a form of exploratory engineering concerned with the construction of structures on an enormous scale. Typically these structures are at least 1,000 kilometers in length—in other words, at least 1 megameter, hence the name...
- RingworldRingworldRingworld is a Hugo, Nebula, and Locus award-winning 1970 science fiction novel by Larry Niven, set in his Known Space universe and considered a classic of science fiction literature. It is followed by three sequels, and preceded by four prequels, and ties into numerous other books set in Known Space...
- Space tetherSpace tetherSpace tethers are cables, usually long and very strong, which can be used for propulsion, stabilization, or maintaining the formation of space systems by determining the trajectory of spacecraft and payloads...
- Non-rocket spacelaunchNon-rocket spacelaunchNon-rocket space launch is a launch into space where some or all needed speed and altitude is provided by non-rocket means, rather than simply using conventional chemical rockets from the ground. A number of alternatives to rockets have been proposed...