SnapDragon
4d ago
Point taken. We just need to hurry up and invent that Epstein Drive!
SnapDragon
5d ago
Cool, I learned something from this. I didn't realize nuclear rockets couldn't be used for the early stages. Thanks. I think you're wrong about them being the most efficient engines extant today - ion engines still have much higher specific impulse, but are only viable in space. And you're still sidestepping the point that upper-stage nuclear rockets (the original topic) and large nuclear payloads are completely separate issues.
SnapDragon
6d ago
Hmm, I think you're talking about two different things. One is the launch, from Earth, of a nuclear-powered rocket (e.g. NERVA). Even if it contains hundreds of kilos of uranium, it's a lot fairer to compare that to an A-bomb like Little Boy (64kg) rather than just the primer of an H-bomb. And, like you said, in an accident a lot less of it is going to vaporize than it would in a proper nuclear bomb.
But I wasn't talking about the payload at all. I guess you're thinking that you'd want to lift 100 tons of U-235 to orbit for space-based nuclear rockets? I agree that's a different kind of risk. And I'm not even sure how valuable nuclear rockets would be for long space trips (there are lots of options once you're up there).
SnapDragon
6d ago
Fissile material is extremely valuable per unit mass, and we're never going to run out of it on Earth, so you wouldn't save much by farming it out of the gravity well. What WOULD be valuable is mining and smelting a large amount of metal or rock that you can use to build large structures in space.
SnapDragon
6d ago
Er, yes, that's what "fallout" means. You missed @RandomRanger's point. One rocket's worth of nuclear material in the atmosphere is barely a blip. Note that even a normal rocket is chock-full of toxic chemicals, which is why we don't launch near population centers. Most normies tend to be off by many orders of magnitude when they intuit how dangerous "nucular" things are.
Hmm, I'd argue the opposite. Sure, there's more bad stuff out there, but there's more ANY stuff out there, and the bad stuff is a much smaller percentage and guarded by things like "safe search" and browser/site warnings, so it's harder to stumble across inadvertently. In the old days it was trivial to just get trolled by somebody and end up at goatse or lemonparty or the Anarchist's Cookbook, and that was just the common stuff. I stumbled across hentai """porn""" that I'd shudder to even describe - I honestly don't think I would even know how to find stuff that fucked up, nowadays. It might not even exist outside of an Onion link.
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