Computer artwork of a future space elevator technology for mass space transportation. The elevator would rotate with the Earth, remaining connected to its distant anchor point on the equator. Electromagnetic propulsion systems could be used for the low-cost transport of people (upper left) and materials into space. Objects descending from orbit would power ascending loads. Immensely strong materials are needed to build this cross between a tower and a rope. Carbon nanotube materials are thought to be suitable for the space section of an elevator.