It would be bad, but it wouldn't really be that bad. A launch failure would not cause a complete detonation (that is trivial to prevent, but difficult to orche

It would be bad, but it wouldn't really be that bad. A launch failure would not cause a complete detonation (that is trivial to prevent, but difficult to orchestrate). A fizzle could be mitigated fairly easily as well, possibly even by putting the warhead on a launch escape system if you really wanted to go overboard. The most likely failure is just the device coming apart and being scattered, but in that situation Pu-239 is not particularly more concerning than Pu-238. More or less just an alpha emitter; not good to ingest, but otherwise pretty safe. We've launched plenty of things with Pu-238 in board.