Consequences of A Failed Orion Test?

If somehow a dummy test of the Orion nuclear-powered rocket been done AND failed, what are the environmental effects?

How far would the radiation contamination spread?

Thanks in advance!
 
Was anyone ever talking about doing this on earth? My understanding was that it was strictly a "run it in deep space" idea.
 

Delta Force

Banned
Was anyone ever talking about doing this on earth? My understanding was that it was strictly a "run it in deep space" idea.

There were proposals to use a large conventional rocket to get it out of the atmosphere and there were also proposals where the rocket would simply be launched away from areas of high population. The scientists who worked on the design crunched the numbers and came to the conclusion that it would release only a fraction of the amount of the (above ground) nuclear tests going on at the time.
 
I know I'm talking from a 21st century viewpoint, but using something like that in the atmosphere seems nuttier than squirel poop.
 
I would guess that the most likely scenario for an Orion launch failure is that the ejection mechanism breaks and the thing crashes. In this case, most of the potential contamination - the plutonium in the propulsion pulse units - will probably remain in or near the vehicle. Given you would never launch the thing from anywhere other than the ocean, that means it probably hits the water, breaks up, and then falls to the ocean floor below. I am by no means an expert on pollution, but I would guess that it is unlikely that detectable levels of plutonium would reach human populations. Even a minimally alert government would begin screening fish before they reach the population, and thereby prevent any significant contamination reaching humans, although potentially at a cost to the fishing industry. (Of course, the Russian response to Chernobyl shows that sometimes governments aren't even minimally alert).

The primary problem with Orion is not what happens if it fails. It's what happens in ordinary, successful operation. It is probable that the human population would be exposed to more radiation as a result of a successful launch than as a result of a failed one.
 
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There were proposals to use a large conventional rocket to get it out of the atmosphere and there were also proposals where the rocket would simply be launched away from areas of high population. The scientists who worked on the design crunched the numbers and came to the conclusion that it would release only a fraction of the amount of the (above ground) nuclear tests going on at the time.

I read that as well, but I thought it only said they concluded it wouldn't cause more than one or two cancers? I really want to know what radiation carcinogenesis models they were using, because I don't believe Linear No-Threshold was standard issue at the time, and that's the modern model. It's been too long since I read Project Orion, but I remember thinking their numbers were off by about an order of magnitude. Maybe I'm misremembering... :confused:
 
I'd tend to think that the consequences of a successful atmospheric test would be quite a bit bigger than a failure. Ultimately nuclear devices are really quite stable, and don't accidentally detonate. Even in a scenario that detonates the conventional primers there are almost no conceivable scenarios where you are going to get detonation, and which point it just becomes a question of how much the cores of the multitude of devices are going to be broken up, and how far that debris will spread. Between the real level of radioactivity of just the material, and the areas such a test could even be considered I'd think that while it could be very expensive to clean up the consequences really wouldn't be that large.

All that said, I really don't understand the appeal of Orion next to something like NERVA. Yes, nuclear explosives are well developed and understood, but so are nuclear reactors and nuclear thermal doesn't involve much more than a reactor and an otherwise conventional engine bell. Add to that the challenges of making the pusher plate system actually work are, to say the least, non trivial, and the amount component of the explosion that is disperses in unhelpful directions and the whole thing feels to me like an interesting idea, but ultimately without much more use than Plowshare (which is to say, IMO, there may be some conceivable use somewhere, but in almost all realistic scenarios there is an option that is, on balance, significantly better). Given what we now know about small and precise nuclear devices combined with the push plate's complications I'm not even sure Orion would be a good idea financially (compared to the alternatives that is).
 
I read that as well, but I thought it only said they concluded it wouldn't cause more than one or two cancers? I really want to know what radiation carcinogenesis models they were using, because I don't believe Linear No-Threshold was standard issue at the time, and that's the modern model. It's been too long since I read Project Orion, but I remember thinking their numbers were off by about an order of magnitude. Maybe I'm misremembering... :confused:

As far as I remember they were assuming the use of pure-fusion bombs (because fusion was right around the corner, as it has been for the last 50 years...), with no fissile elements in them at all. In the event pure fusion devices have not made it into production so far, and so the pulse-bombs used would have to have a fissile trigger even if they were then boosted. This would make them much dirtier than the assumptions.

As has been said already, the main problems with Orion only start if it works...
 
I believe some of the advantages of Orion is that it allows for a higher top speed (due to greater exhaust velocity), and is more scalable to extremely large sizes. Don't quote me on that, though.

Also, to echo what others have said, a failure isn't going to result in also the onboard propulsion system detonating. Rather, you're going to end up with core materials spread around the general vicinity at worst.
 

Delta Force

Banned
As far as I remember they were assuming the use of pure-fusion bombs (because fusion was right around the corner, as it has been for the last 50 years...), with no fissile elements in them at all. In the event pure fusion devices have not made it into production so far, and so the pulse-bombs used would have to have a fissile trigger even if they were then boosted. This would make them much dirtier than the assumptions.

As has been said already, the main problems with Orion only start if it works...

I think by fusion bombs they meant thermonuclear bombs, as opposed to fission bombs (atomic bombs). Much of the power in a thermonuclear bomb comes from the fusion reaction triggered by the primary (fission) stage. I have seen estimates for the top speed of Orion designs using fusion and even antimatter charges, but the orginal Orion study was based on late 1950s technology and atomic and thermonuclear bombs.
 
I believe some of the advantages of Orion is that it allows for a higher top speed (due to greater exhaust velocity), and is more scalable to extremely large sizes. Don't quote me on that, though.

Also, to echo what others have said, a failure isn't going to result in also the onboard propulsion system detonating. Rather, you're going to end up with core materials spread around the general vicinity at worst.


Actually, I think you pretty much NEED it to be huge. It's not scalable to make is small. The bigger the ship the smoother the ride, and when your talking about a put-put engine where the puts are nuclear EXPLOSIONS, making the ride smoother is a serious concern.
 
I think by fusion bombs they meant thermonuclear bombs, as opposed to fission bombs (atomic bombs). Much of the power in a thermonuclear bomb comes from the fusion reaction triggered by the primary (fission) stage. I have seen estimates for the top speed of Orion designs using fusion and even antimatter charges, but the orginal Orion study was based on late 1950s technology and atomic and thermonuclear bombs.

I haven't seen many sources on the subject, so you could be right. I do seem to recall, though, that while they may have been using the propulsive force of 1950's bombs in their calculations they were assuming the bombs could be made without needing a fission stage. If that was possible, the bombs would indeed be very 'clean'. So far, however, it has not been possible.
There were other schemes as well - I remember something about coating the pusher plate with graphite - but I have no idea how well that would have worked.
 
I believe some of the advantages of Orion is that it allows for a higher top speed (due to greater exhaust velocity), and is more scalable to extremely large sizes. Don't quote me on that, though.

The advantage of Orion is chemical rocket levels of thrust with ion drive levels of exhaust velocity. And exhaust velocity improves with larger vehicles, because larger pusher plates are more efficient at catching the shockwave, and because larger bombs are more mass-efficient for their yield. The only other technology I'm aware of that could hypothetically be built in the near future and get anything like the Orion's performance is the Nuclear Salt-Water Rocket, which may not work anyway.
 

Delta Force

Banned
I haven't seen many sources on the subject, so you could be right. I do seem to recall, though, that while they may have been using the propulsive force of 1950's bombs in their calculations they were assuming the bombs could be made without needing a fission stage. If that was possible, the bombs would indeed be very 'clean'. So far, however, it has not been possible.
There were other schemes as well - I remember something about coating the pusher plate with graphite - but I have no idea how well that would have worked.

Just like you can make dirty bombs you can make clean bombs. Also thermonuclear bombs produce less fallout for their yield than atomic bombs.

As for the graphite, it was part of the heat ablation system and was not meant to reduce fallout. It turns out steel can withstand temperatures well above its melting point for the duration of a nuclear detonation, but a little bit of graphite dust sprayed onto the surface of plates before every blast makes it even more resistant. A potential issue is that graphite has been founs to behave strangely in space (acting as a source of friction instead of a lubricant) because of the lack of water.
 
Actually, I think you pretty much NEED it to be huge. It's not scalable to make is small. The bigger the ship the smoother the ride, and when your talking about a put-put engine where the puts are nuclear EXPLOSIONS, making the ride smoother is a serious concern.

Actually the plans were for ships as small as 300t and device yields of .03kt (30t). Wiki article.
You could probably go smaller than that with conventional explosives but I doubt that would be as efficient as a conventional rocket.
There were tests using a small scale ship and C4 explosives.
Project Orion Video
 
There were several incarnations of the Project Orion concept. The original idea, conceived in the 50s, was to use a single large conventional explosion to lift the craft into the air, then use nuclear explosions (provided by modified nuclear warheads) to lift to orbit and beyond. At the time, the US, UK, and USSR were routinely conducting above-ground nuclear tests, and fallout was considered an acceptable cost if the nukes were set off in remote enough areas. This version was eventually scrapped in 1963, due to a treaty banning above-ground nuclear tests.

The second major incarnation was a much smaller, lighter-weight Orion craft which was designed to be lifted into orbit by conventional rockets (probably the first stage of a Saturn V), then use Orion drive to break orbit and travel to Mars or the outer solar system. This made little headway because 1) the improvement over a pure-conventional rocket was more marginal, since most of the energy cost in interplanetary travel is simply reaching orbit, 2) in order to fit on a conventional rocket, the Orion craft needed to be scaled down heavily (becoming less efficient because a major feature of the original Orion concept was that it became more efficient as it scaled up to larger crafts) and needed to be made with light-weight construction techniques (also negating a major feature of the original concept, that it could be "built like a battleship" rather than having to scrimp every spare ounce out of the design), and 3) it became known during this time period that setting off nukes in low orbit would EMP entire continents.

The third major incarnation was the pure fusion variation mentioned upthread. Instead of using modified nuclear weapons, it would use a variation of the inertial confinement fusion reactor concept: lasers, electron beams, or ion beams would hit pellets of deuterium and tritium, heating and crushing them enough to undergo fusion. This never got past the drawing board, since inertial confinement fusion on anywhere near the scale needed (or even the scale necessary to make a viable commercial reactor) was and is decades of difficult and expensive research away.

There's two major sub-concepts in the pure fusion variation: a resurrection of the original Orion concept, using pure fusion as a way of avoiding the fallout problem, or on a craft constructed in orbit that would use the drive to accelerate to several percent of the speed of light for an interstellar flyby mission (most notably in the Project Daedalus and Project Longshot conceptual studies).
 
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