In A Hoist to the Heavens, Bradley Carl Edwards looks at the economics of a space elevator — “a superstrong, lightweight cable stretching 100 000 kilometers from Earth’s surface to a counterweight in space”:
It all boils down to dollars and cents, of course. It now costs about US $20 000 per kilogram to put objects into orbit. Contrast that rate with the results of a study I recently performed for NASA, which concluded that a single space elevator could reduce the cost of orbiting payloads to a remarkably low $200 a kilogram and that multiple elevators could ultimately push costs down below $10 a kilogram. With space elevators we could eventually make putting people and cargo into space as cheap, kilogram for kilogram, as airlifting them across the Pacific.
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For example, 95 percent of the mass of each mighty Saturn V moon rocket was used up just getting into low-Earth orbit. As science-fiction author Robert A. Heinlein reportedly said: “Once you get to Earth orbit, you’re halfway to anywhere in the solar system.” With the huge cost penalty of traveling between Earth and orbit drastically reduced, it would actually be possible to quarry mineral-rich asteroids and return the materials to Earth for less than what it now costs, in some cases, to rip metal ores out of Earth’s crust and then refine them.