I think nukes are perfectly legal to use in space, as long as they're only used for propulsion or asteroid/comet deflection (think saving the Earth or some future space colony from a major impact). Using them as weapons against other countries or your own people is what's illegal, due to the Outer Space Treaty.

stargate38:

I think nukes are perfectly legal to use in space, as long as they're only used for propulsion or asteroid/comet deflection

 If you will use nukes in space you still will make a lot of radiation and flight in this zone will be (probably) restricted or something like that . If you(not exactly you) will use a lot of nuclear stuff in space you might make whole space around yourself radioactive and more dangerous

just an assumption

Maybe it should only be used outside a certain distance of any planet (i.e. 1,000,000 km). That would reduce the risk of irradiating planets. And at such large scales, radiation drops off pretty fast, so there would be minimal risk, unless you just happen to fly through the radiation trail another craft left (they take some time to dissipate). Also, the ships could be lead-shielded to protect the passengers/crew from the nuke radiation, as well as cosmic radiation.

z4dg9ssw135:

stargate38:

If you(not exactly you) will use a lot of nuclear stuff in space you might make whole space around yourself radioactive and more dangerous

I'm fairly sure radiation emission isn't much of a problem in space, especially near giant planets or in interplanetary space, given the magnetospheres of worlds like Jupiter give off deadly radiation by themselves and the Sun is fully capable of lighting up a neon canister if you're close enough, I mean it's literally a star. Also, there isn't much in space to keep the radiation in one spot so it should dissipate quickly in all directions.