Climbing a Cable to Space

A space elevator is a long thin cable, anchored on the Earth end and held in place on the space end by a counterweight of ballast. The central balance point of the cable is located at a geo-synchronous orbit level, keeping the cable steady over the anchor point. The weight of the cable (and ballast) out in space beyond the central balance point is the same as the weight of cable below the central point. The space end wants to hurl itself farther out into space and the inner end wants to fall with gravity down to the surface of the Earth. The two forces balance each other, making the assembly stable.

Once the elevator cable is in place and stable, elevator cars or “climbers/lifters” can use the cable as a guide, along with some form of climbing motor that moves the climbing car up the cable. Using solar energy to power electric motors is one consideration. Instead of needing to meet a high escape velocity using a massive chemical rocket, the elevator car can move slowly and steadily up into space, requiring much less energy to life the same amount of payload into space.

At this point, the primary obstacle to making this concept work is the strength of cables that are available. In order to accomplish the task as described above, the cable will need to be roughly 100,000 kilometers in length and will need to be strong enough to support its own weight along with the weight of climbing cars and the payloads they carry. Until recently, no available material substances reached those requirements. Now, carbon nanotubes are being considered, but they have not yet reached the lengths or production levels needed.

SEE ALSO:
Space Elevator
Lunar Space Elevator
Commercial Space Lift

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