Orbital explosion

[Droflet]

Calling out to the brains trust. Okay, a big nuclear explosion in orbit. Am I correct in assuming that the EM pulse would not only stuff communications but he radioactive fallout would irradiate the area?
Secondly, explosion occurred part way into a stable asteroid field that surrounds the planet. Hey, I know but this is science fiction so I can write anything I want, as long as no one can prove me wrong.
So, Chronauts, what do you think would be the outcome. It's a massive explosion by the way.

 

[Vertigo]

I believe explosions in vacuum, even massive ones, can be remarkably ineffectual other than for stuff very close. With no atmosphere to transmit the shockwave it will only be 'transmitted' by the debris being thrown out. So the result of your explosion depends very much on how it is arranged. If it is inside one of the asteroids and sufficient to blow it apart then there will be a lot of debris flying around which could damage stuff. If it is on a spaceship of some sort then there will only be the debris of the spaceship itself to cause problems ie. much less than an asteroid. If it is just a nuclear bomb on say a missile then you only have the debris of the missile; much less again.

Not sure about the fallout. Nuclear fallout is mostly due to the dust debris from the explosion and if there isn't any then, well, then there isn't any. I think the only fallout you will have will be the material of the bomb itself plus whatever else it blows up.

Nuclear weapons (or any explosive weapons) in space are not really much use unless they are very close to or contacting their target. Though, as you suggest, the EM pulse might do some damage, but don't forget that in space everything is exposed to an awful lot of nasty stuff like cosmic rays, so equipment in space is likely to be pretty hardened to that sort of thing. I'm not sure how a nuclear explosion EM pulse compares to the normal radiation in space from the local star etc.

 

[Droflet]

Thanks for that, Vertigo. Hmm, more info. The explosion is caused by a massive space platform, four million tons thank you very much. It has four massive reactors and when one blows they all blow. That combined with the debris, both large and minute, from the asteroids might cause a bit of a problem for our hero. I shall think upon your sage advice. Thanks again.

 

[Vertigo]

Well I'd wait for confirmation and/or other ideas from some of our more knowledgeable colleagues, I may be totally wrong.

Another point to note is that if you blow up your space station then the debris is likely to disperse quite rapidly.

 

[Ray McCarthy]

Any gas /liquid very rapidly expands and has no effect. Solids keep travelling at same speed till they hit something, reach higher orbit or enter atmosphere only the most energetic particles will leave orbit.

 

[Droflet]

Thanks for that, Ray. So, irradiation of the area then, is a no? (I hope not because it will f*ck up a perfectly good story)

 

[Brian Rogers]

Radiation in an atmosphere consists of thermal, blast wave, and nuclear. On an atmosphere the thermal and blast are actually more impactful than nuclear fall out as the density of the atmosphere works to slow the gamma rays and neutrons and reduce the overall radius exposed to lethal doses.

In space however the blast wave essentially disappears (in your station explosion, obviously its the material which causes damage) as well as the thermal radiation. BUT the gamma rays and neutrons can actually spread much farther, hundreds of miles in radius in fact, and remain lethal to humans. There is nothing to reduce the potency of the radiation except for distance so in fact, yes, you would irradiate a much larger area than you would on the surface of Earth.

Sorry if that's not the answer you were hoping for...

 

[Ray McCarthy]

So, irradiation of the area then, is a no?

Only the instantaneous X-Ray and gamma radiation at the time of explosion. A very short pulse, travelling at speed of light, subject to inverse square law, so at two kilometres may be harmless and at 10 kilometres is x25 weaker.
The radioactive dust/components (from the material of space station) will be travelling much more slowly and also spreading out, a radioactive shell with safe hollow centre rapidly decreasing in danger as it the surface area increases and the short half life products decay.

Somewhat faster than physical particles will be Alpha radiation (atomic particle) and Beta radiation (electrons) somewhat faster again. Spreading out in a shell between radiation pulse and slower debris shell.

So unlike an air burst atomic bomb or ground burst there is no static fall out. The original area (apart from facing surface of nearby asteroids) would be safe in minutes and in days the whole area fairly safe (apart from facing surface of nearby asteroids).

There would also be very much less radioactive contamination (no soil sucked in mushroom) and the isotopes of an exploding reactor are rather different to a bomb too.

 

[Brian G Turner]

radioactive fallout would irradiate the area

Isn't fallout simply dust and debris made radioactive by a nuclear explosion? In which case, due to the lack of debris created by a nuclear explosion in space, wouldn't this be a non-starter?

Also note that space is already full of radiation, not least the bombardment from the Sun.

 

[Droflet]

Thanks, guys.

 

[Brian Rogers]

How "harmless" the radiation would be depends on the size of the explosion. If we're talking 20KT warhead then yeah, at 10 km you would have less than 500 roentgens which is basically the lethal limit of exposure a person can have. IF there are shields however, you could simply display an intense aurora surrounding the shields of nearby satellites or ships as the energetic particles hit and interact with a magnetic field.

There will be NO fallout of course, just the instantaneous radiation that depending on intensity would still be lethal. In space the radiation intensity is far worse for far longer without any atmosphere to slow it. about 10-15 times the radius of radiation on Earth (not talking about fallout, just initial radiation from explosion

 

[Ray McCarthy]

about 10-15 times the radius of radiation on Earth

Don't forget the Inverse Square law applies
That sounds high.

 

[Brian Rogers]

http://history.nasa.gov/conghand/nuclear.htm

Got it from NASA haha, I'm not that smart. But yes that's applying the inverse square law. Atmosphere really slows radiation down that much!

 

[Droflet]

Well, I'm certainly glad we got the Inverse Square issue sorted out. Again, thanks everyone for your invaluable input. I'm putting this puppy to bed now. Think I'll rely on the second law of sf writing which states, 'Write whatever you want. As long as no one can prove you wrong.' Cheers.

 

[Droflet]

Well, I'm certainly glad we got the Inverse Square issue sorted out. Again, thanks everyone for your invaluable input. I'm putting this puppy to bed now. Think I'll rely on the second law of sf writing which states, 'Write whatever you want. As long as no one can prove you wrong.' Cheers.

 

[Droflet]

Well, I'm certainly glad we got the Inverse Square issue sorted out. Again, thanks everyone for your invaluable input. I'm putting this puppy to bed now. Think I'll rely on the second law of sf writing which states, 'Write whatever you want. As long as no one can prove you wrong.' Cheers.

 

[hardsciencefanagain]

Indeed,it looks like you could use a rest

 

[Droflet]

Well, I'm certainly glad we got the Inverse Square issue sorted out. Again, thanks everyone for your invaluable input. I'm putting this puppy to bed now. Think I'll rely on the second law of sf writing which states, 'Write whatever you want. As long as no one can prove you wrong.' Cheers.

 

[hardsciencefanagain]

Indeed,it looks like you could use a rest

 

[Droflet]

Ah, just noticed this. Can I blame the system? It wasn't my fault I tell you. The system, it's the bloody system. Hmm. Time for a nap.