An 'antigravity' propulsion system was proposed at the Space Technology and Applications International Forum (STAIF) in Albuquerque on Febuary 14 by Dr. Franklin Felber. His new exact solution to Einstein's gravitational field equation gives hope to space enthusiasts that it might be possible to accelerate space craft to speeds approaching that of light without crushing the contents of the craft. If it works, it could be even better than apergy, as described by science fiction writer Percy Greg in 1880.

Dr. Felber's paper states that a mass moving faster than 57.7 percent of the speed of light will gravitationally repel other masses lying within a narrow 'antigravity beam' in front of it. This "beam" intensifies as the speed of the mass approaches that of light.

The paper shows how to use the repulsion of a body speeding through space to accelerate large spacecraft quickly while reducing internal tidal forces that could tear the cargo apart. The paper argues that the payload would "fall weightlessly" in an antigravity beam as it is accelerated to a substantial fraction of light speed.

"Based on this research, I expect a mission to accelerate a massive payload to a 'good fraction of light speed' will be launched before the end of this century," said Dr. Felber. "These antigravity solutions of Einstein's theory can change our view of our ability to travel to the far reaches of our universe."
(From Physicist to present solution)

On the downside, it does not appear that Dr. Felber has published any previous papers in the field of general relativity. Also, the space engineering conference in Albuquerque probably has lower standards for peer review than those at a gravity conference.

Gravity is a favorite source of propulsion for science fiction writers. In his 1880 novel Across the Zodiac, writer Percy Greg refers to a marvelous material called apergy:

I had satisfied myself that only one thing needful was as yet wholly beyond the reach and even the proximate hopes of science...

I needed a repulsion which would act like gravitation through an indefinite distance and in a void - act upon a remote fulcrum, such as might be the Earth in a voyage to the Moon, or the Sun in a more distant journey. As soon, then, as the character of the apergic force was made known to me, its application to this purpose seized on my mind. Experiment had proved it possible, by the method described at the commencement of this record, to generate and collect it in amounts practically unlimited.
(Read more about apergy)

Prior methods for spacecraft propulsion include the bird-like Gansas of Bishop Godwin's 1638 book The Man in the Moone. Next came gunpowder, which was used in the colossal Columbiad launching cannon used in Jules Verne's 1867 novel From the Earth to the Moon. Neither method accelerated travellers to an appreciable fraction of light-speed.

As far as I know, the only real, working example of using large masses for "gravitational propulsion" is the well-known "slingshot" or "gravity assist" method used successfully in the Voyager, Galileo and Cassini programs. Historians of science differ on the source of the idea, but the basic idea was described by science fiction writer Ray Cummings in his 1931 novel Brigands of the Moon (see Ray Cummings' gravity assist).

Read Dr. Felber's paper "Exact relativistic 'antigravity' propulsion and news articles here and here. Thanks to Adi and others who wrote in with this one.

(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)