A Bishop Ring is a type of hypothetical rotating space habitat originally proposed in 1997 by Forrest Bishop. Like other space habitat designs, the Bishop Ring would spin to produce artificial gravity by way of centripetal force. The design differs from the classical designs produced in the 1970s by Gerard K. O'Neill and NASA in that it would use carbon nanotubes instead of steel, allowing the habitat to be built much larger. In the original proposal, the habitat would be approximately 1,000 km (620 mi) in radius and 500 km (310 mi) in width, containing 3 million square kilometers (1.2 million square miles) of living space, comparable to the area of Argentina or India.
Because of its enormous scale, the Bishop Ring would not need to be enclosed like the Stanford torus: it could be built without a "roof", with the atmosphere retained by artificial gravity and atmosphere retention walls some 200 km (120 mi) in height. The habitat would be oriented with its axis of rotation perpendicular to the plane of its orbit, with either an arrangement of mirrors to reflect sunlight onto the inner rim or an artificial light source in the middle, powered by a combination of solar panels on the outer rim and solar power satellites.
Also unlike the 1970s NASA proposals, where habitats would be placed in cislunar space or the Earth-Moon L₄/L₅ Lagrangian points, Forrest Bishop proposed the much more distant Sun-Earth L₄/L₅ Lagrangian points as the sites for the habitats.
Bishop Rings are a common type of habitat in the fictional universe of the Orion's Armworldbuilding project; their radius varies from as little as 100 km to as much as 1000 km (62—620 mi).
The eponymous ring installations of the Halo series are essentially Bishop Rings with slightly divergent proportions. Notably, the Halo rings are located in orbit around gas giants rather than at lagrangian points.