O'Neill cylinder

Artist's depiction of a pair of O'Neill cylinders
A diagram of a pair of O'Neill cylinders (Island Three)

An O'Neill cylinder (also called an O'Neill colony) is a space settlement concept proposed by American physicist Gerard K. O'Neill in his 1976 book The High Frontier: Human Colonies in Space.[1] O'Neill proposed the colonization of space for the 21st century, using materials extracted from the Moon and later from asteroids.[2]

An O'Neill cylinder would consist of two counter-rotating cylinders. The cylinders would rotate in opposite directions to cancel any gyroscopic effects that would otherwise make it difficult to keep them aimed toward the Sun. Each would be eight kilometers (5 mi) in diameter and 30 kilometers (20 mi) long, connected at each end by a rod via a bearing system. Their rotation would provide artificial gravity.[1]

Interior view, showing alternating land and window segments
  1. ^ a b O'Neill, Gerard K. (1977). The High Frontier: Human Colonies in Space. New York: William Morrow & Company. ISBN 0-688-03133-1.
  2. ^ "Space Resources and Space Settlements,1977 Summer Study at NASA Ames Research Center". NASA. Archived from the original on 29 July 2012. Retrieved 20 October 2012.