Nuclear Pulse Propulsion: Absurd Unscientific Concept?

[NERVAfan]

The biggest problem I think is EMPs in low space frying satellites for really nasty effects on communications -- don't know if the bombs are big enough for this though (I know the "Starfish Prime" test caused lots of satellite failures, but it was 1.4 megatons).

[78stonewobble]

They have many safety mechanisms of course.

However, they have most likely never been transported en mass, as would be necessary to refuel an Orion.

You're right about that.

Still I'm not so worried about the bombs themselves, I'm more apprehensive that the mining and processing of the fissile materials will be handled... too cheaply... and not with the right eye to... Not letting it into nature (I don't mind radioactive waste in ie. subduction trench, I mind it in the river next to a city).

[Rakaydos]

I really only see 2 sources for a production Orion drive.

Constructed an fueled in the asteroid belt, or North Korea decides to do a moon landing.

[KerbMav]

You're right about that.

Still I'm not so worried about the bombs themselves, I'm more apprehensive that the mining and processing of the fissile materials will be handled... too cheaply... and not with the right eye to... Not letting it into nature (I don't mind radioactive waste in ie. subduction trench, I mind it in the river next to a city).

I rewatched Prometheus and this just reminded me of "weren't stupid enough to make this crap in their own backyards".

The whole idea was most likely made up by a pacifist to engage the super-power-space-racers into depleting their arsenal in orbit.

[Dodgey]

I know how nuclear weapons work, and I also know about plastic explosives being used.

However, if the conditions are right, an electrical current could arise and cause the nuke to explode.

Well sure, in the same sense as living in a dry climate increases the chances of your fuel tank bursting into flames as you refuel due to the larger about of static electricity. Technically you are correct but the probability difference is infintesimaly small.

And who is to say they wouldn'd separate the deatonators from the warheads during launch.

[Red Iron Crown]

And who is to say they wouldn'd separate the deatonators from the warheads during launch.

That would seem to be an elementary precaution. The detonators probably shouldn't be installed until just before a thrusting event.

Might even be a good idea to launch the detonators separately from the rest of the bombs, that way a launch failure doesn't put all the parts to a working nuclear bomb in one place.

[Dodgey]

That would seem to be an elementary precaution. The detonators probably shouldn't be installed until just before a thrusting event.

Might even be a good idea to launch the detonators separately from the rest of the bombs, that way a launch failure doesn't put all the parts to a working nuclear bomb in one place.

I think in that event I would be more amazed that the probability of that occurring than the horrifying devastation of the nuclear devices devices detonating.

[-Velocity-]

However, if the conditions are right, an electrical current could arise and cause the nuke to explode.

No, the chances of that are small enough to be ignored.

However, there is a chance that the detonation circuits could operate correctly, but just at the incorrect time. This would occur through extreme human incompetence, carelessness, or poor engineering.- like, maybe they accidentally left a safety switch in the "arm" position, maybe they accidentally dropped the weapon, and maybe some other safety switch was designed incorrectly. There are rumors (confirmed with recently declassified documents) that something like this nearly DID happen with a multi-megaton weapon over North Carolina back in 1961-

http://www.theguardian.com/world/2013/sep/27/atomic-bomb-north-carolina-video

An excerpt -

"The weapon dropped, power was now coming on and the arming rods had been pulled, the barrel switches began to operate, the next thing was for the parachute to deploy." Crucially, Summers adds: "When it hit the ground it tried to fire."

There was only one safety device left between the bomb and disaster: a switch known as a pre-arming ready-safe switch that could turn the bomb on and off through the normal operation of a 28-volt signal sent from the B-52's cockpit. But even that switch was known by nuclear safety experts to be deeply unreliable.

"Unfortunately, there have been thirty-some incidents where the ready-safe switch was operated inadvertently," notes Charlie Burks, a former Sandia nuclear weapons systems engineer. "We are fortunate that the weapons involved at Goldsboro were not suffering from that same malady."

All that said, this applies to implosion-type nuclear weapons. Implosion-type weapons are not going to detonate unless exactly-timed signals are delivered to the detonators of the explosive lenses. So you could blow up implosion-type nuclear weapons without fear of them detonating. However, nuclear weapons that assemble a supercritical mass that is supercritical at regular pressures (like the gun-type design used in the Little Boy bomb) are very unsafe and COULD detonate if they were subjected to an explosive blast. Modern nuclear powers do not use any of these weapons, however.

Edited April 8, 2014 by |Velocity|

[Rakaydos]

All that said, this applies to implosion-type nuclear weapons. Implosion-type weapons are not going to detonate unless exactly-timed signals are delivered to the detonators of the explosive lenses. So you could blow up implosion-type nuclear weapons without fear of them detonating. However, nuclear weapons that assemble a supercritical mass that is supercritical at regular pressures (like the gun-type design used in the Little Boy bomb) are very unsafe and COULD detonate if they were subjected to an explosive blast. Modern nuclear powers do not use any of these weapons, however.

Not to mention, gun type deviced have a much higher minimum yield. The weakest of them would be too powerful for Orion.

[TheGatesofLogic]

Not too mention that the above statement is not entirely accurate since a bomb that fizzles still technically has a yield (but yes the EFFECTIVE yield in an Orion scenario would jump dramatically as the velocity of the male unit is increased, and would not be suitable for it).

regardless, people fear nuclear pulse propulsion overmuch, if done with intelligent deigns and its course and detonation location and timing was computed by anyone smarter than the Department of Defense there would be absolutely no issue whatsoever, it is literally unimaginable that any noticeable radioactive fallout would occur anywhere if done properly.

[Psycix]

Lowering the minimum yield is possible through antimatter catalyzation.

http://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_pulse_propulsion

About the fallout:

The Linear No Treshhold model predicts that every launch will globally kill a few hundred people.

Luckily, the LNT-model is not proven and is known for grossly overestimating kill count. More and more people start to argue that it is downright wrong, and that a very low dose of radiation over a very large population doesn't harm anyone at all, as we may have an immunity against very low dosages of radiation.

Edited April 8, 2014 by Psycix

[Red Iron Crown]

If we've got antimatter production at reasonable cost we can probably ditch nuclear power altogether.

[SargeRho]

No, we can't. Producing antimatter will always take more energy than you can get back out of it.

[Red Iron Crown]

I meant for rockets, should have been more clear.

[Nuke]

think of antimatter as energy storage in this case.

[KASASpace]

Well sure, in the same sense as living in a dry climate increases the chances of your fuel tank bursting into flames as you refuel due to the larger about of static electricity. Technically you are correct but the probability difference is infintesimaly small.

And who is to say they wouldn'd separate the deatonators from the warheads during launch.

Why not just build the nukes in orbit, shipping up parts with launchers.

[KASASpace]

No, we can't. Producing antimatter will always take more energy than you can get back out of it.

Not if we collect it over Saturn.

(Jupiter's magnetic field is too strong)

[SargeRho]

GL transforming gamma rays efficiently into electricity.

[NERVAfan]

Lowering the minimum yield is possible through antimatter catalyzation.

http://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_pulse_propulsion

About the fallout:

The Linear No Treshhold model predicts that every launch will globally kill a few hundred people.

Source, please?

The only calculation on the subject I've heard of is Dyson's from the original Orion project era and that was 0.1 - 1 person per launch. And I think what they used back then would have been some version of the LNT model, even though not the current one...

Luckily, the LNT-model is not proven and is known for grossly overestimating kill count. More and more people start to argue that it is downright wrong, and that a very low dose of radiation over a very large population doesn't harm anyone at all, as we may have an immunity against very low dosages of radiation.

Also true. It doesn't really make biological sense that it should be linear at low doses, few things are, and radiation is a part of the natural environment we evolved in so having no defenses at all agianst it is also questionable.

Now I'm not sure I'm ready to say that low doses have no effect at all (they may well not - but we don't know yet). I have heard that people living in higher background radiation areas do not have higher cancer rates, but I don't know that for sure...