In the 1950s, rocket visionary Wernher von Braun proposed a 250 foot wide, inflated, reinforced nylon wheel orbiting 1,075 miles above the Earth, to serve as a navigational aid, meteorological station, military platform and way station for space exploration. The wheel shaped station could be easily rotated, creating a centripetal force that would serve as an artificial gravity for the health of the astronauts inside (prolonged weightlessness has harmful effects). Von Braun wanted the station to be permanently occupied, serving as a center from which to stage a lunar exploration program. Yet in the 1960s, NASA adopted the Apollo Program, which called for astronauts to transfer to a lunar landing vehicle after achieving lunar orbit, bypassing the construction of von Braun's wheel.