Bernal Sphere

A Bernal sphere is a type of space habitat intended as a long-term home for permanent residents, first designed in 1929 by John Desmond Bernal.

Bernal's original proposal described a hollow non-rotating spherical shell, filled with air, 10 miles (16 km) in diameter, with a target population of 20,000 to 30,000 people.

In 1975-1976, Dr. Gerard K. O'Neill designed Island One, a changed Bernal sphere with a diameter of only 500 m (1,600 ft) for a population of 10,000. It would rotate about twice each minute to produce a full Earth artificial gravity at the sphere's equator. A "Crystal Palace", formed by multiple rings next to the sphere at both ends, would be used for agriculture. Sunlight was to be provided to the interior of the sphere using external mirrors to direct it in through large windows near the poles. O'Neill also designed a larger version, Island Two, 1800 meters in diameter, with an equatorial circumference of nearly 6.5 km (4 miles). In addition to Island One and Island Two Bernal spheres, Gerard K. O'Neill also designed another type of space habitat: Island Three, also known as O'Neill cylinder, with an even far larger size than Island Two.

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Category:Space colonization