from Moore's Lore by Dana Blankenhorn
April 28, 2005
Stepping Toward a Space Elevator

richard smalley.jpgAmid all the recent stories about the U.S. abandoning basic science I offer a counter-example.

Rice University, my old school has an $11 million deal with NASA to develop carbon nanotubes that will, at first, be big enough to act as power cables and could, with time, produce the technique for a space elevator.

Last year a team under Nobel Prize Winner Dr. Richard Smalley (right) found that nanotubes assume the properties of metals in the presence of a magnetic field, Smalley has always been excited about tubes' superconducting properties. The problem has been manufacturing.

The contract emerged following a successful workshop in Boerne, outside San Antonio, co-sponsored by NASA and Rice. The Rice manufacturing technique is called HiPco, and originally involved growing tubes on catalytic iron in chambers of carbon monoxide, producing carbon dioxide and nanotubes at a rate of nearly a half-gram per hour.

The idea is to expand on on this by starting with "seed" tubes that "teach" the carbon around them how to grow into the required shape. The specific goal is to produce one yard of nanotube "wire" after four years. Dr. Smalley describes the final result as looking like a fishing line.

By starting the process with the desired shape in the chamber the scientists hope to avoid the problem of having to "sort" whatever tubes emerge from the HiPco process.

Dr. Smalley envisions using nanotubes on power grids to dramatically cut the loss of power from metals like copper. It's estimated nanotubes can run 10 times more power, by weight, than conventional metals. NASA hopes materials like nanotubes can cut the weight of future shuttles by half, which in turn would cut the fuel cost of getting them into orbit.

But if you can grow pure nanotube wire, pure enough to transmit energy, you could also grow a pure nanotube strong enough to hold up a space elevator, since the tube would be a single molecule.