Bussard Ramjets

This theoretical spacecraft drive, proposed by the late Robert Bussard, never got as far as even a serious proposal for a real-life spaceflight… but boy, did SF writers ever love it in the sixties, seventies and eighties.  Larry Niven had his early Known Space colonists traveling to Alpha Centauri, Sirius, Procyon and Tau Ceti by Bussard ramjet; Poul Anderson had one go horribly wrong in the classic Tau Zero; Robert J. Sawyer had a character in his first book use one as a murder weapon.  And that’s just scratching the surface.  The idea was to project an electromagnetic field that would scoop hydrogen out of the interstellar medium to use as fuel.  Sadly, it appears that space for a few hundred light years around from us (the “Local Bubble”) is not as rich in hydrogen as Bussard had thought. But his design contributed to so many good stories that it deserves to be remembered.  And who knows, maybe some aliens in a more hydrogen-rich area of the galaxy are using some variant of it right now.  Maybe they’ll approach our area, run into trouble and need help…

Links:

http://en.wikipedia.org/wiki/Bussard_ramjet
http://www.daviddarling.info/encyclopedia/I/interstellar_ramjet.html