Tuesday, March 5, 2013

Clean Space Travel

We’ve written in the past about inventions that seem to be originally described in various popular culture outlets. For example, smart watches here,  here, and here, levitating cars, and moisture farming, and iPads and tablet computers. The latter were described by Arthur C. Clarke and Stanley Kubrick in 2001: A Space Odyssey.

Clarke popularized the concept of space elevators in his 1978 novel, The Fountains of Paradise. His protagonist, Vannevar Morgan, said

“If the laws of celestial mechanics make it possible for an object to stay fixed in the sky, might it not be possible to lower a cable down to the surface, and so to establish an elevator system linking earth to space? … Now the deep-space factories can manufacture virtually unlimited quantities of hyperfilament. At last we can build the Space Elevator … ”

Clarke proposed geosynchronous satellites in a 1945 Wireless World article.

There are presently four US patents with the phrase ‘space elevator’ in the title; US 6,981,674 is representative. “System and method for space elevator” was invented by James G. Dempsey of Oshkosh, WI. Oshkosh is the home of the Experimental Aircraft Association, and annually hosts “The World’s Greatest Aviation Celebration”.  It is also a prolific center for innovation, with 1501 US patents listing it as an inventor’s city. Dempsey’s January 2006 invention provides,

"A system and method for a Space Elevator using a transport tether shaped into double catenary with one catenary below synchronous orbit altitude and the second catenary above synchronous orbit altitude and while also forming a harmonic oscillator using a combination of gravitational and centripetal forces with the zero crossing of the harmonic oscillator at an altitude of approximately one half synchronous orbit altitude of attached elevator."

A catenary is the curve formed by a uniform cable hanging from two supports in a uniform gravitational field. Dempsey’s patent envisions a counterweight in orbit at about 88,000 km (54,681 mi), beyond geosynchronous altitude (36,000 km or 22,369 mi), a ribbon-shaped tether (containing carbon nanotubes), a base station, a transition point, a synchronously orbiting station, and an elevator car. All of these are described in Clarke’s novel.

Curiously, the patent does not cite The Fountains of Paradise, or any of the other documentation that Clarke lists at the end of the book. None of the other three patents (US 6,491,258, US 7,971,830; also by Dempsey, US 8,196,867) do either.

It’s a shame that one of the major proponents and early popularizers of this clean space transportation technology (there are only a few bugs yet to work out) did not get the recognition he deserved from the inventors, attorneys/agents, or examiners.