An O'Neill cylinder is an orbiting space colony composed of two large cylinders which rotate in opposite directions to replicate the effects of Earth's gravity. Amazon and Blue Origin founder Jeff Bezos foresees a future in which O'Neill cylinders can be used to move industry into space and allow Earth to be used exclusively for residential and recreational purposes.
The idea for using rotating cylinders to create extraterrestrial living and working spaces was first proposed in the 1970s by Princeton physicist Gerard K. O'Neill in his book The High Frontier: Human Colonies in Space. According to Dr. O'Neill, a pair of cylinders several miles long could be built incrementally in space and orbit safely around the planet. To allow people to live and work inside the cylinders, some interior spaces would be park-like. The cylinders' continual rotation would negate any gyroscopic effects and optimize the way solar panels could be used to provide power. Windows and mirrors could alternate to support circadian rhythm and give workers the impression of day and night.
When proposing the idea of colonizing space, O'Neill said any technical suggestions should be guided by these four principles:
- A worthwhile line of technical development must have a useful lifetime of at least several hundred years.
- A line of technical improvement is more likely to be beneficial if power and control are decentralized.
- A proposal to improve the human condition only makes sense if it has the potential to give all people, whatever their place of birth, access to the energy and materials needed for their progress.
- Improvements are of value if they tend to reduce the scale of cities, industries, and economic systems to small size, so that bureaucracies become less important and direct human contact becomes more easy and effective.
In this archived footage, Dr. O'Neill discusses how what we have learned from past colonization efforts on planet Earth will help us colonize space.
Related proposals for industrializing outer space
Other large, theoretical space structures include the Bernal Sphere, the Stanford Torus and the Dyson Sphere.
This space colony would accommodate about 10,000 people, and serve as a residential and manufacturing complex. The residents' chief export would be energy, generated at solar power stations and transmitted to Earth. The sphere would rotate 1.9 times per minute, generating centrifugal force to replace gravity. Advocates optimistically thought habitation might begin as early as the 1990s. It was named after John Desmond Bernal, an early 20th century Irish physicist and Marist author. He is quoted as having said on his 70th birthday in 1969: "I am sure that you share my hope that in the not too distant future science may come to be used exclusively for the benefit of all mankind."
A space colony design accommodating 10,000 people was proposed following a 10-week program in engineering systems design held at Stanford University and the Ames Research Center of the National Aeronautics and Space Administration in 1975. The design was published in a study titled simply, Space Settlements: a design study, and published by the 1975 summer faculty fellowship program. A torus is any object characterized by, in part, a tubular shape with constant diameter and circular bore.
Named after British theoretical physicist Freeman John Dyson, the Dyson Sphere, is a hypothetical structure that completely encompasses a star and captures much of its energy output. In theory, such a megastructure could be used by space explorers to fuel enormous energy needs for traveling vast distances.