Future Space Exploration

What is the advantage of a space elevator over a space shuttle?
Answered by Craig C. Freudenrich and Discovery Channel
  • Craig C. Freudenrich

    Craig C. Freudenrich

  • Discovery Channel

    Discovery Channel

  1. In an episode of "Star Trek Voyager" titled "Rise," the characters Neelix and Tuvok crash on a planet. They attempt to reestablish contact with Voyager by fixing a maglev space elevator. This device rides along a cable from the surface to a geostationary orbit above the planet. The idea of a space elevator is not new. It was first proposed by a Russian scientist named Yuri Artsutanov in 1960 and popularized by science fiction authors Arthur C. Clarke and Charles Sheffield.

    The principle behind the space elevator is this: Build a cable that goes to geostationary orbit (22,500 miles, or 42,300 kilometers) or higher. One end of the cable is anchored to an oil platform in an ocean at the equator. At the other end is a large counterweight to keep the cable taut. All you have to do to put a payload in orbit is climb the cable and release the payload at the top. The payload will orbit the Earth at that altitude. The power for the elevator climbers is beamed from the surface by a free electron laser. (For a really good animation, see www.spaceward.org/elevator.)

    The problem with the 1960s space elevator idea was that there was no material strong and practical enough to make the cable. In the 1980s, scientists discovered carbon nanotubes, essentially rolled sheets of graphite that were strong, light and flexible enough to make a space elevator cable.

    Research is currently underway to build a practical tether for a space elevator. In February 1996, space shuttle flight STS-75 tested a tethered satellite as part of the space elevator concept. The tether was let out about 12.3 miles (19.7 kilometers). Because the tether crossed the Earth's magnetic field, it generated electric current, which was measured and could potentially be used to power a space elevator [NASA].

    A working space elevator could greatly reduce the cost of sending payloads into orbit. Most of that cost comes from the amount of fuel required to lift the payload off the ground. Also, the size of the payload is limited by the rocket's capabilities. By changing the thickness of the elevator's tether, the payload size could be increased to more than 1000 tons (907 metric tonnes).

    In short, a space elevator could carry larger payloads into Earth orbit more often and at lower costs than conventional rockets.

    Space Tourism Qa2
    (AP Photo/Mikhail Metzel)

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  2. Although space shuttles are reusable, they are also extremely expensive, costing $10,000 per pound ($22,000 per kilogram) to launch. The scientists developing a space elevator hope it will be reusable and much more affordable. They estimate that it will cost the elevator only $100 to $400 per pound ($220 to $880 per kilogram) to take cargo and people into space, and make space travel a much more common occurrence.

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