The thing is, even if a rocket blows up and a few dozen pounds of uranium get strewn about, it isn't anywhere near the disaster people think it is. Until we can rationally compute dangers instead of simply assigning infinities to the dangers, we're not going to get anywhere.

There is ~4.5 billion tons of uranium already in sea water [1].

If that fact surprises you, you may just have not known it. If that fact scares you or makes you want to deny it, you're probably still stuck in the irrational fear I'm talking about. The world is not a pristine place with no radioactivity in it until Man comes along and somehow, like, manufactures it from nothing but his sheer Evil for the nefarious purpose of destroying the environment, mu-hu-ha-ha-ha. It's a thing that's already out there. It's not that terrifying if we take basic precautions that, it turns out, we already take because you know what's way scarier than a few dozen pounds of uranium falling near you? A flaming exploding rocket falling on you. So we already don't launch over cities and such.

And we really won't progress as long as people can not only act irrationally about the real dangers, but think they're being more moral by being irrational about the dangers than people actually using their brains and that it's vital to yell at the people using their brains and attempt to socially pressure them into just going with the herd and assigning infinite danger to the scariness of OMGRadiation!!!1!.

[1]: http://large.stanford.edu/courses/2012/ph241/ferguson2/