Artwork of the interior of a Stanford Torus. This is a design for a space station proposed by NASA in 1975 at Stanford University. It consists of a torus with a diameter of 1800m and a cross-sectional diameter of 130m for the habitable section. The ring is connected to a central hub via a series of six spokes, which also allow transport from the hub to the habitable section. Rotating at one revolution a minute the station provides an artificial gravity equivalent to roughly 0.9 Earth gravities, and can house around 10,000 to 40,000 people.