chornedsnorkack said:
KJ_Lesnick said:
Plus if that thing crashes...
Kosmos satellites routinely do, by design.
RORSAT (Radar Ocean Recon SAT)
had routinely done it, by design ("COSMOS" was a U.S.-applied designation to anything put into Low Earth Orbit by the Soviets that wasn't otherwise identifiable - though these included the entire RORSAT range they also included a number of anonymous but civilian satellites as well as a number of interplanetary probes and other equipment that failed to escape LEO as well as test equipment, including a test of the intended Soviet LEM).
The RORSAT program was an earlier Cold War program now defunct, with most of the mini-reactors being ejected into a stable high orbit; however, at least two RORSAT sats have returned to Earth with their reactors, including one that crashed into the Sea of Japan after a failed launch and another that failed to achieve LEO and burned up over northern Canada, leaving an extensive radioactive debris field. A third RORSAT nearly failed to eject its reactor when spent, but a backup system managed to launch the reactor into a lower than intended, but evidently still stable high orbit.
If anything, this only highlights the concern, though RTGs (Radioisotope Thermoelectric Generators) are fairly common for interplanetary probes and possibly some satellites. Rather than a full-blown nuclear reactor, these devices merely convert the natural radioactive emissions of radioisotopes such as Pu-238 or Sr-90 into electrical power. Though these devices do not generate significant electrical output, they have the advantage of having a long "battery life," especially if a radioisotope with a very long half-life is used (hence why Pu-238 and Sr-90 are the most popular RTG fuel sources).
Besides, even a modern "compact" nuclear reactor is going to be huge. The only payload the NB-36 was able to carry was the reactor itself. Never mind the 6 tons of lead shielding it carried just behind the crew compartment, protecting only the crew (the amount of shielding needed for a passenger plane would make said plane more suitable as a submarine)