[mchouza]

Project Orion was much more than science fiction (http://www.scribd.com/doc/28668567/Nuclear-Pulse-Space-Vehic...) though it was much less than operational. Very big Orion spaceships would have used fusion explosions (http://galileo.phys.virginia.edu/classes/321.jvn.fall02/Dyso...), but not the relatively small ones that were subjected to detailed analysis.

[podperson]

You say "conceptual design" and I say little more than science fiction. Potato, potato -- some kind of solid fuel rocket is going to lift a shield strong enough to protect a crew with 90 days of "emergency" supplies from small stomic bombs going off... Right. And this is for a lunar mission!

There's more detailed stuff out on the warp drive NASA has funded study on, meanwhile the grandparent made it sound like someone had built one of these things (only with fusion bombs) in 1952 and it was rusting in a shed somewhere.