Via MeFi, we learn of the Pluto Project, a Cold War era weapon program. Sweet Christ, what a scary idea.

a locomotive-size missile that would travel at near-treetop level at three times the speed of sound, tossing out hydrogen bombs as it roared overhead. Pluto’s designers calculated that its shock wave alone might kill people on the ground. Then there was the problem of fallout. In addition to gamma and neutron radiation from the unshielded reactor, Pluto’s nuclear ramjet would spew fission fragments out in its exhaust as it flew by.

Fortunately, it never got built; here’s part of why:

But what drove the last nail into Pluto’s coffin was a question so deceptively simple that the wizards at the lab might be excused for deliberately overlooking it: Where do you flight-test a nuclear reactor? “How are you going to convince people that it is not going to get away and run at low level through Las Vegas — or even Los Angeles?” asks Jim Hadley, a Livermore physicist and Pluto alumnus who now works on detecting foreign nuclear tests for the lab’s hush-hush Z Division. There was, admits Hadley, no way of guaranteeing that Pluto would not become a nuclear-powered juggernaut beyond its inventors’ control — a kind of airborne Frankenstein, a flying Chernobyl.

Every so often, it utterly blows our mind that we didn’t all end up dead during the nuclear brinksmanship era. Duck and cover our ass.