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If I could haul this 75 kg of meat into space, I would do it. But unfortunately, it is too expensive. And given rocket technology, it probably will always be too expensive. What can be done? Answer: Build a bridge.

The price of a place on the Space Shuttle goes for over $9000 per kilogram (assuming that the Shuttle program will continue). Conventional rockets might get the price down to about $1000 per kilogram, but that is still simply too high. How can mankind haul the massive tonnage needed to really colonize the moon, planets, and stars? Consider a developed inner solar system: Rockets would be a massive barrier to commerce, almost like choosing to ferry cargo over a river rather than bridging the shores with a superhighway.

Why are rockets awkward? I think that the problem comes down to the rocket equation: Large objects require a lot of fuel to get off the ground, and that massive amount of fuel means that the object gets larger. The only way to transcend that problem is move the fuel out of the capsule: Spend energy moving the cargo, not moving fuel that will be burned up anyway.

I first ran across this idea in science fiction books. Arthur C. Clarke used space elevators in his book Fountains of Paradise. Fredrick Pohl also had an accelerating "ribbon" in his Gateway series. Kim Stanley Robinson used cables in Red Mars.

Some have used the space elevator concept as a necessary step in the development of space. Marshall Savage, in his opus The Millennial Project suggested using a train-like system that would accelerate cargo to escape velocities. Savage cannot be faulted for thinking small: The train is just an early stage in a detailed plan to colonize the entire galaxy. His driving thought is interesting: Humanity must expand, or it shall fail.

But the space elevator is (slightly) more than just speculation. NASA Institute for Advanced Concepts awarded Highlift Systems with a grant to study the elevator concept. They appear to have a detailed feasibility study worked out. They recently spun off another company, Liftport, to work on the commercialization of the elevator. The goal is to have the first cargo by 2018. The elevator concept has also been discussed widely by experts, as reviewed by Space.com.

The major technological barriers right now include the development of extremely strong materials (such as carbon nanotubes). I think that the technological barriers will be overcome as time goes on... The major difficulty will be to build a strong enough business case.

I hope to see such things in my lifetime. I would be proud to participate in the development.




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