ALBUQUERQUE, NEW MEXICO -- What do you get if you cross a magnetic space sail with a rapid-fire machine gun? If you do your math right, you might end up with something like the SailBeam interstellar space ship.

The SailBeam is so-called because it uses laser-driven microsails to carry extra force to the actual ship. Laser-launched at rates of one sail every few seconds for a period of years, a "beam" of millions of sails is used to push an interstellar vehicle onward and outward. The sails transfer their momentum to the larger spacecraft as they are ionized by a vehicle-mounted laser, with the resulting plasma striking a magnetic field a MagSail -- that is emitted by the star-bound craft.

"It’s like using a machine gun on shore and accelerating a bunch of little bullets that bounce off the back of a row boat to push it where you want it to go," Kare told SPACE.com.

After several years of acceleration, the probe coasts to its destination, and using its reconfigured MagSail as a drag brake, slows down to a dead stop within a selected star system.

"The phrase 'bat out of hell' is the correct one."
     SailBeam creator Jordin Kare

"All the numbers seem to hang together," Kare said. "What I’m trying to do is find a way to do an interstellar mission without having to invoke near magical technology."

A SailBeam mission en route by mid-century, perhaps sooner, is conceivable, Kare said. Even at the speeds attainable by the interstellar probe -- around a tenth of the speed of light -- the craft would take some 30 to 40 years to arrive at a selected star.

"But at least that’s within the foreseeable future. If you launch it when you are a graduate student, you get the results around the time you retire," Kare said.

Kare’s work on high-acceleration micro-scale laser sails for interstellar propulsion is through a research grant from the NASA Institute for Advanced Concepts (NIAC) program. No show-stoppers were found, with the SailBeam idea made workable using known physics and materials, he reports.

The microsails would be made from double-layers of artificial diamond film.

The little sails go from a standing start in space up to a tenth of the speed of light in three and a half seconds. "The phrase ‘bat out of hell’ is the correct one," Kare said.

A SailBeam mission would be a product of many high-tech threads, including solar power satellites, laser propulsion, large space optics, solar sails and MagSails. "There is a clear set of mutually-reinforcing technologies that may well be able to take us to the stars," Kare said.

By scaling up the SailBeam system, probes carrying people is a possibility, Kare said, although you couldn’t offer them a round-trip ticket. The amount of time taken to cross the vacuum void is one thing. Then there’s no way to build a laser at the other end to send passengers back.

"So right now, you’d have to have very dedicated people that would volunteer to go," Kare said.

When the first crew of stellar sailors would take the journey is difficult to predict.

"I can look out a century and think it is possible. It’s not a 1,000 years away. It doesn’t require God-like powers," Kare said.

Romance of the adventure

Interstellar travel is "a tough request," said John Cole, head of the revolutionary propulsion research project office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

On the one hand, we must remain vigil regarding breakthrough propulsion concepts. However, wild-eyed ways to travel faster than the speed of light, claimed from time to time, should be met with some skepticism and a demand for extraordinary evidence.

"But I’m an eternal romantic. There is romance in this adventure. There’s not a physicist around that I’ve run into that believes that the standard model of general relativity and quantum mechanics, as it stands right now, is complete and there’s nothing else to be learned. Obviously, there’s more to be learned," Cole said.