Since Robert Goddard launched a 10-foot rocket from a New England farm more than 80 years ago, the basic principles of space travel haven't changed much. Still required: a violent combustion of fuel and oxygen to propel the vehicle. Unless, maybe, you have a laser and a couple of mirrors. Young K. Bae, a maverick one-man rocket research institution in Tustin, believes he has hit on a propulsion technology that could revolutionize space travel, finally overcoming the limits of chemical rockets, which are slow and dangerous and need vast amounts of fuel. The 51-year-old physicist calls it the photonic laser thruster. This overcomes the physical barriers of current rocket technology," he says, pointing to a tiny laser encased in glass. Hurling ships into space with light beams has been the stuff of science fiction novels for decades, but Bae says he has proved that it really is just science. He says a laser beam bouncing off two mirrors facing each other was able to exert force on one of the mirrors, albeit ever so slight. The discovery came in December, but Bae waited months to reveal the experiment to verify that the measuring devices were accurate and that the results could be repeated. Franklin B. Mead, a rocket propulsion expert at the Air Force Research Laboratory, calls it "pretty incredible." The photonic laser thruster can in theory be made much more powerful -- strong enough to propel a spacecraft to near light speed. "If it proves out it would be revolutionary," says Carl Ehrlich, a retired aerospace engineer who has worked on the space shuttle and other rocket programs. Within a year or two, [Bae] will attempt to have the laser device lift an object the size and weight of a compact disc. Ehrlich will be watching. "We're still using the same technology developed by Goddard. We need a breakthrough," he says.

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