@S1-A.ARPA,@MIT-MC.ARPA:dmw@cmu-cs-unh.arpa (05/31/85)
From: Hank.Walker@CMU-CS-UNH A few years ago, Bob Forward gave a talk here on the science behind his Analog serial "Rocheworld" (later published as the book "Flight of the Dragonfly"). He chose to use a laser-driven light sail in the story, but he also looked into using antimatter. We already make antimatter in particle accelerators. We just make very small quantitities, and do it very inefficiently. But then no one has really investigated antimatter production. You don't use antimatter by mixing it with equal amounts of matter and getting gamma rays. You mix a little antimatter with a lot of hydrogen. The antimatter is merely a light-weight method of heating hydrogen. You keep the amount of hydrogen fixed at millions of kilograms, and vary the amount of antimatter used, depending on the trip length. I seem to recall that interplanetary missions used grams of antimatter, while interstellar missions used kilograms. I don't think I'd be real comfortable riding around with 20 quatrillion joules of potentially explosive energy in my tail.