Editing Lunar space elevator (section)

{{short description|Proposed transportation system}}
[[Image:Lunar space elevator.svg|thumb|350px|Diagram showing equatorial and polar Lunar space elevators running past {{L1}}. An {{L2}} elevator would mirror this arrangement on the Lunar far side, and cargo dropped from its end would be flung outward into the [[Solar System]].]]

A '''lunar space elevator''' or '''lunar spacelift''' is a proposed transportation system for moving a mechanical climbing vehicle up and down a ribbon-shaped tethered cable that is set between the surface of the [[Moon]] "at the bottom" and a docking port suspended tens of thousands of kilometers above in space at the top.

It is similar in concept to the better known [[space elevator|Earth-based space elevator]] idea, but since the Moon's surface gravity is much lower than the Earth's, the engineering requirements for constructing a lunar elevator system can be met using materials and technology already available.  For a lunar elevator, the cable or [[tether]] extends considerably farther out from the lunar surface into space than one that would be used in an Earth-based system. However, the main function of a space elevator system is the same in either case; both allow for a reusable, controlled means of transporting payloads of cargo, or possibly people, between a base station at the bottom of a [[gravity well]] and a docking port in outer space.

A lunar elevator could significantly reduce the costs and improve reliability of soft-landing equipment on the lunar surface. For example, it would permit the use of mass-efficient (high specific impulse), low thrust drives such as [[ion drive]]s which otherwise cannot land on the Moon. Since the docking port would be connected to the cable in a [[microgravity]] environment, these and other drives can reach the cable from [[low Earth orbit]] (LEO) with minimal launched fuel from Earth. With conventional [[rocket]]s, the fuel needed to reach the lunar surface from LEO is many times the landed mass, thus the elevator can reduce launch costs for payloads bound for the lunar surface by a similar factor.