By the way, it's worth pointing out, to those who want to make a judgement on the reasons project Orion could not be implemented nowadays, that nuclear detonations are effectively a modern tabu.
This tabu is effective, has proven extremely useful (no detonations of nukes in a war since 1945) and thus cannot be considered the sign of a scientifically ignorant society.
We've had hundreds (or thousands, if you count sub-design-yield) detonations since 1945, including several in space (Hardtack Teak and Orange, and USSR equivalents).
And lots of them were for purely posturing purposes, with little scientific or direct weapons-testing value.
The US probably could have pulled off something like Orion in the 1990s or maybe even today, since there's not a direct cold war threat. Domestic politics probably kill it, though, but if it were branded as "nuclear pulse drive" with sub-10kT pulses, it might be possible.
You can't launch an Orion spaceship without violating the https://en.wikipedia.org/wiki/Partial_Nuclear_Test_Ban_Treat.... Also given the estimated 0.1 to 1 human deaths from cancer per launch (I am using Freeman Dyson's estimate here), it is hardly a politically viable vehicle.
>given the estimated 0.1 to 1 human deaths from cancer per launch (I am using Freeman Dyson's estimate here), it is hardly a politically viable vehicle.
Considering that one coal plant statistically kill about 70 people per year due to air pollution, I think it's more a matter of insufficient political power than the product of rational policy.
The cancer increase would be for launching from the ground/atmospheric use, which is a non-starter. I'm talking about use to run an orbital shuttle/tug/etc. between Earth and Mars. It would never enter atmosphere, and probably be constructed in space.
The US has enough weapons that it could comfortably withdraw from the treaty, or claim that these launches are not "tests" but rather some other use.
The fallout is from neutron radiation of the ground, which doesn't happen in space. The amount of direct radiation from the uranium that is used is actually quite small.
And it would be trivial to point the exhaust away from earth. Space is full of radiation anyway, from the sun.
The fallout is from neutron radiation of the ground, which doesn't happen in space. The amount of direct radiation from the uranium that is used is actually quite small.
Can you cite this? I think the major dose component of nuclear fallout is from fission products, not neutron activation products. For example, skimming through these appendices on dose calculations from historic nuclear weapons tests [1](e-h), most of the significant radioisotopes are either fission products, or transuranic activation products from the weapon (e.g. Am-241). The environmental activation products discussed, C-14, Mn-54, Fe-55, and Co-60, are much less significant.
It's a matter of quantity - a ground burst produces enormous amounts of radioactive material. An air (or space) burst only has a few KG of radioactive material.
"Air Bursts. .... there is essentially no local fallout from an air burst."
"Surface Burst ..... In contrast with air bursts, local fallout can be a hazard over a much larger downwind area than that which is affected by blast and thermal radiation."
I think you're misunderstanding that reference. The amount of radioactive material is not that different; the distinction is that a ground burst localizes some of it at ground zero. It creates a small area which will be an acute radiation hazard for a short time. An air burst gives a very large, diffuse, atmospheric plume.
In the maps from the CDC link, large areas -- whole states (check out pages f29-f35) -- are contaminated with low levels of airborne radioactive fallout. From the isotope data, it's clear most of this is from the weapons, not environmental activation products. The doses are too low to be immediately dangerous (<1 mSv), but can have chronic health effects, as a slightly increased cancer risk.
You can tune your weapon to have MUCH lower fission products; essentially the smallest size fission primary you can (ideally, with boosters), and then a big fusion stage and no U-238 tamper. Conventional thermonuclear weapons are usually fission-fusion-fission since a U-238 casing for the third stage is a cheap and compact way to scale up the weapon, but that last fission stage is responsible for >95% of the fission products/long lived pollution. A "neutron bomb"/ERW/etc. is one application of the low-radioisotope weapon (and a "dirty bomb", a non-critical radiological weapon, is the other extreme).
I'm still hoping fission-free fusion weapons are not possible before I can live somewhere other than Earth, since all arms control essentially rests of preventing access to fissile materials. Once you eliminate that gate, it becomes much easier for a clandestine group to build a weapon. Pure fusion weapons would be amazingly destabilizing and, if they were approximately as hard to make as seems likely, would absolutely get used by some group.
That's not really how fallout works. Fallout occurs primarily when you detonate a bomb near the ground or the water, causing it to suck up a bunch of dirt/water, irradiate it, and distribute it throughout the atmosphere. With a fusion bomb, you could end up with some leftover plutonium from the fission stage, but that's not the primary source of fallout.
Didn't Dyson's son write in the book that part of the reason for the treaty's signing was internal politics to kill a competitor to NASA?
1. Those 0.1-1 dead is from a period of much worse cancer treatments than will be available a few decades after an Orion launch.
2. It is bad risk counting. The cost per life is a factor whenever e.g. roads are built and speed limits are set. ("We will get ~ X less deaths/decade if we build the motorway differently, but it would cost over our limit for $/life".) Also, just transporting materials/people when designing/building an Orion ought to be a lot more than one dead.
Do you mean 'taboo', as in something that's considered off-limits due to cultural sensitivities? (Wondering out loud if the etymology is similar to voodoo and related suspicious stuff)
This tabu is effective, has proven extremely useful (no detonations of nukes in a war since 1945) and thus cannot be considered the sign of a scientifically ignorant society.
Having said that, Orion would be quite cool.