There isn't a space agency or private firm on the planet with a spotless launch record. And we're not talking about cheapo rockets—last year, the craft carrying NASA's $280-million Orbiting Carbon Observatory fizzled out and crashed into the ocean near Antarctica. It's a bummer when a satellite ends up underwater, but it's an entirely different story if that rocket is packing a few hundred pounds of uranium. And if the uranium caught fire, it could stay airborne and circulate for months, dusting the globe with radioactive ash. Still seem like a good idea?