Robert Bussard, a giant when it came to interstellar space flight concepts, passed away recently. He was 79 years old. He was best known for creating the concept of the Bussard Ram-jet fusion method for interstellar space travel. His later works involved inventing practical methods for fusion power reactors.
The concept of the Bussard ram-jet is simple, accelerate the spaceship up to 6% c ( lightspeed), unfurl 6,000 kilometers (later revised to 60,000 kilometers) of electromagnetic “wings” or “scoop” to put a negative charge on hydrogen atoms to “suck” them up like a huge vacuum cleaner, compress them down and use the “fuel” to run the fusion reactor and propel the ship to .99 c. The reason being once after the ship reached .06 c, the process would start to be self sustaining.
Later studies of the concept proved the method to be impractical due to the fact that you have accelerate the ship first (that first .06 c is a bitch) and the drag coefficient tended to cancel out what acceleration you got out of it.
But the concept inspired three of my favorite novels; Tau Zero, written by Poul Anderson, Orbitsville by Bob Shaw and A Deepness In The Sky by Vernor Vinge (who also coined the term “technological Singularity). All made the Bussard ram-jet method of starflight an essential plot device. Especially Orbitsville, I loved the flickerwing ships! Even Gene Roddenberry employed the concept on his Starfleet vessels like the Enterprise, the warp nacelles are in fact bussard collectors with linear particle accelerators that strip hydrogen atoms for fuel (anti-protons)!
The renewed interest with interstellar travel is fuelled by the almost daily discovery of extrasolar planets, especially one in particular, Gliese 581d, which may be the first Earth-type extrasolar world discovered. Old tech that has been on the shelf such as Orion (nuclear-pulse/bomb/pusherplate) is being updated (yes bombs, as in nukes!).
Solar sail and laser propulsion are being considered again and last, but probably the most important one, some variance of antimatter propulsion. The form of anti-matter tech that’s showing the most promise and can probably provide the speed necessary is an anti-matter initiated, helium3 fuelled fusion torch. Only a few micrograms of anti-matter is needed to light off the heavy helium3 atoms and once lit, it’ll boost a small payload to 10-15% c easily. Enough for a 30-40 year flyby journey to Proxima Centauri. To get to Gliese 581d in that amount of time would require a real small payload, but one capable of producing a sizable electromagnetic field to protect it from hard x-rays and interstellar dust hitting the field with the power of atomic bombs (all interstellar probes will need shielding).
The idea of a spaceship “living off the land” so to speak was beautiful. You can get up to lightspeed on minimal fuel and once the process started, it was self-sustaining. Too bad engineering reality threw cold water on it.
But that doesn’t diminish Bussard’s vision in the least. His ideas prompted research in finding ways to get practical fusion power to the people, forever banishing energy shortages to the history books. For that he shall always be remembered.
Links about Robert Bussard :
Fiction using the Bussard Ram-jet concept :
Continuing Work on Dr. Bussard’s Project: