What is a space elevator?

By Marshall Brain


http://video.google.com/videoplay?docid=-1753157427833077745

In the video, you learn about NASA's plans for a space elevator. Here are some of the interesting details revealed in the video:
  • The space elevator will use a "cable" or "ribbon" that is made of carbon nanotubes. The ribbon will be three feet wide, thinner than a sheet of paper, and will stretch from the earth (somewhere near the equator) 62,000 miles into space. At the end of the ribbon there will be a counterweight. The centripetal force of the counterweight will keep the ribbon stretched tight.

  • An elevator vehicle will use electric motors and treads to "drive" up the ribbon. The electricity will come from lasers on the ground that shoot upward and hit an array of solar cells on the vehicle. The solar cells will convert the laser light to electricity for the motors. The advantage of this approach is that it is much lighter than having batteries or and engine+fuel on the vehicle.

  • The big advantage of the space elevator is that it will cost a lot less to get things into orbit. Right now we use huge rockets carrying a gigantic amount of fuel to get something into orbit. (The space shuttle, for example, needs about 4 million pounds of fuel to get into orbit). That means that it costs about $10,000 to get a pound of equipment into space. Once the ribbon is in place, the cost of putting something into space with the space elevator will be much lower.

  • The video also mentions the possibility of riding to the end of the ribbon and then releasing things into space from there, heading to destinations like Mars.
If you would like to learn more about the space elevator, try this article about the space elevator.


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