bluefoxlucid writes: The Orion Drive never got off the ground primarily because, essentially, blowing up a lot of nuclear material in atmosphere is a bad idea. That means a new kind of nuclear bomb--for example, clean-pumped fusion that uses a non-fissile source to initiate chain reaction hydrogen fusion into helium with only neutrino output and no ionizing radiation or fall-out--would provide a great enabler for space flight. Unfortunately, such an awesome bomb would also provide great opportunity for military uses--and associated politics. Infinitely scalable (notably smaller) nukes with no fall-out are just conventional bombs, right? Is the promise of effective launch and space flight worth the bitter in-fighting at the UN table that would occur just for implying new research into new nukes, as well as the moral implications of greater, more deadly warfare?