I think NERVA and its Soviet equivalent RD-0410 were much more practical and plausible. Unlike Orion which was complete vaporware, both these projects reached the ground test prototype stage.
NERVA / RD-0410 are basically like chemical rockets but better (maybe 800s specific impulse, vs. 300 for a chemical rocket). In contrast, Orion was 6,000s to maybe 100,000 theoretically.
Article briefly talked about delivery, which is tricky to do precisely at best of times, but didn't really mention how to address delivery into a nuclear blast. Hundreds of meters behind the craft about once a second doesn't seem like it would be enough time for the blast to clear so would get in the way of sending a new capsule backward. Anyway I'm sure it's just an implementation detail
A lot of the work was done to a design point of 0.25 seconds, and Dyson's book says the issue there wasn't the blast clearing, but just being able to move the machinery fast enough. I kind of share your puzzlement; I can see the blast clearing this quickly in space (the debris moves at tens of thousands of km/sec) but not in the atmosphere.
The blast clears that quickly in the atmosphere because the shockwave and debris move at-or-faster-than the speed of sound, so a few hundred meters is tenths of a second or less. You sit inside the mushroom cloud, of course, but the important part is gone quickly.
The Rapatronic camera was used to take these kinds of pictures, and you can see that the actual blast front is around 20 meters across after 1 millisecond (!!) https://en.wikipedia.org/wiki/Rapatronic_camera
I've thought that if this idea is picked up it would have to be in space. Testing the rocket on the surface of the moon (point the plate straight up) would probably have been necessary anyway. Ordinary chemical rockets can be tested on the Earth's surface, this concept, not so much.
This is among the reason I've thought nuclear waste should be disposed of in space. Send the stuff onto the moon; if future lunar inhabitants want to mine it for plutonium in the naturally radiation-soaked landscape that is the lunar surface, let them.
Reprocessing is very expensive; $1000/kg and up. Launch to space will likely become much cheaper than this as fully reusable launch vehicles become available. Even if the spent fuel must be armored against accident the cost of launching it to LEO, and then to the moon, is likely to become much cheaper than the cost of reprocessing it here on Earth.
Space disposal has the positive advantage that the seven very long lived fission products are removed from the biosphere, along with the very long lived actinides like Np-237.
A version of this idea was mentioned in one of the Three Body Problem books. There, the bombs were pre-positioned along a path and detonated sequentially like dominos, with a vehicle riding the blast waves.
It is more similar to the Medusa method. Lots of ideas have been proposed. One problem is getting the nukes prepositioned (and they won't easily stay in one spot!) with chemical rockets is quite challenging (rather than carrying them and launching them along the way) and also they would actually need to be set in groups of 3 to provide balanced forces along an axis, or alternately along a parabolic helix to compensate for directional errors.
Wild cowboy ideas of yore. Will we ever be able to make it safer to use on earth or would we save that for a moon base -get to the moon and from there blast away with these atomic fahrting machines…
With any luck, by the time we're serious about sending big spacecraft out and about we'll have figured out a workable fusion drive. You'd still need to launch them from space since they're a little spicy from a "don't stand downwind" perspective, but unimaginably better than using nukes against pusher.
Sometimes I think that while it may be appealing to mine gold or platinum or whatever out of the solar system, what people really need to figure out how to do is mine uranium. While I could advocate with a straight face that maybe we need to freak out a bit less about lifting the occasional few dozen pounds of uranium into orbit, and point out that more radioactive material has already been launched than people realize, it is fair to observe that we probably can't afford to make lifting hundreds of pounds of fission fuel into orbit the sort of routine event it needs to be to really have a space civilization. One of the biggest major issues with any sort of space habitation is access to dense energy sources. You can smooth over a lot of other problems and get a lot more slack in the system if you have a lot of energy available to play with. Part of the challenge with current space technology is that you start out on the very edge of feasibility as it is.
With hindsight being 20/20 and all, it always makes me laugh at how 1950s pro-atomics a lot of things seemed to be. Yes, it was the new, like AI is today so everyone was all about it. Yet there never seemed to be any concerns of the downsides of things like the pesky nuclear waste or fallout. Looking back at films and magazines, the feel of TFA and Fallout are not out of place which is part of what makes them good.
I think NERVA and its Soviet equivalent RD-0410 were much more practical and plausible. Unlike Orion which was complete vaporware, both these projects reached the ground test prototype stage.
https://en.wikipedia.org/wiki/NERVA
https://en.wikipedia.org/wiki/RD-0410
NERVA / RD-0410 are basically like chemical rockets but better (maybe 800s specific impulse, vs. 300 for a chemical rocket). In contrast, Orion was 6,000s to maybe 100,000 theoretically.
This is a really enjoyable read. Majiec is a great writer and speaker. A breath of fresh air compared much of modern blog/essay content.
Where modern is post 2000 not 2020!
https://idlewords.com/2006/04/argentina_on_two_steaks_a_day....
https://idlewords.com/2014/07/sana_a.htm
I revisit https://idlewords.com/2007/04/the_alameda_weehawken_burrito_... every few years.
Also a big fan of https://idlewords.com/2010/03/scott_and_scurvy.htm
“Pez dispenser for Armageddon” is incredible imagery
The Zapp & Roger shout-out in the title is gold too.
Or Pepsi Cola, depending on one's age.
This idea is a significant part of Anathem by Neal Stephenson.
Also featured in the 1985 novel Footfall by Niven and Pournelle.
Anathem was so chock full of interesting ideas, too bad the last parts of it were so rushed (or at least felt that way to me).
I always describe it as an excellent 300 page novel crammed into 900 pages.
This is the clearest explanation of why I never really liked Stephenson.
That's most of Stephenson's books. 90% world building and then 10% story at the end.
Article briefly talked about delivery, which is tricky to do precisely at best of times, but didn't really mention how to address delivery into a nuclear blast. Hundreds of meters behind the craft about once a second doesn't seem like it would be enough time for the blast to clear so would get in the way of sending a new capsule backward. Anyway I'm sure it's just an implementation detail
A lot of the work was done to a design point of 0.25 seconds, and Dyson's book says the issue there wasn't the blast clearing, but just being able to move the machinery fast enough. I kind of share your puzzlement; I can see the blast clearing this quickly in space (the debris moves at tens of thousands of km/sec) but not in the atmosphere.
The blast clears that quickly in the atmosphere because the shockwave and debris move at-or-faster-than the speed of sound, so a few hundred meters is tenths of a second or less. You sit inside the mushroom cloud, of course, but the important part is gone quickly.
The Rapatronic camera was used to take these kinds of pictures, and you can see that the actual blast front is around 20 meters across after 1 millisecond (!!) https://en.wikipedia.org/wiki/Rapatronic_camera
In a vacuum, there isn’t a fireball hanging around for the next charge to cross; the plasma is moving outward at thousands of km/s.
I've thought that if this idea is picked up it would have to be in space. Testing the rocket on the surface of the moon (point the plate straight up) would probably have been necessary anyway. Ordinary chemical rockets can be tested on the Earth's surface, this concept, not so much.
This is among the reason I've thought nuclear waste should be disposed of in space. Send the stuff onto the moon; if future lunar inhabitants want to mine it for plutonium in the naturally radiation-soaked landscape that is the lunar surface, let them.
> This is among the reason I've thought nuclear waste should be disposed of in space. Send the stuff onto the moon
Congrats; you have come up with a way to make nuclear waste disposal 100x more dangerous and 1000x more expensive!
You need to think more clearly about this.
Reprocessing is very expensive; $1000/kg and up. Launch to space will likely become much cheaper than this as fully reusable launch vehicles become available. Even if the spent fuel must be armored against accident the cost of launching it to LEO, and then to the moon, is likely to become much cheaper than the cost of reprocessing it here on Earth.
Space disposal has the positive advantage that the seven very long lived fission products are removed from the biosphere, along with the very long lived actinides like Np-237.
And set the stage for "Space 1999"'s lunar escape from earth.
https://en.wikipedia.org/wiki/Space_1999
Nice set design, but honestly unwatchable. An accidental testament to the genius of ST:TOS.
> There are some drawbacks to the nuclear bomb rocket.
You don't say.
A version of this idea was mentioned in one of the Three Body Problem books. There, the bombs were pre-positioned along a path and detonated sequentially like dominos, with a vehicle riding the blast waves.
It is more similar to the Medusa method. Lots of ideas have been proposed. One problem is getting the nukes prepositioned (and they won't easily stay in one spot!) with chemical rockets is quite challenging (rather than carrying them and launching them along the way) and also they would actually need to be set in groups of 3 to provide balanced forces along an axis, or alternately along a parabolic helix to compensate for directional errors.
https://www.centauri-dreams.org/2024/04/17/medusa-deep-space...
Note: there is a paywall much later in the post, but even the free part is a wonderful read.
I think this set a record for me on how much article was available before the paywall.
I am trying to be friendly with the paywall.
Wild cowboy ideas of yore. Will we ever be able to make it safer to use on earth or would we save that for a moon base -get to the moon and from there blast away with these atomic fahrting machines…
With any luck, by the time we're serious about sending big spacecraft out and about we'll have figured out a workable fusion drive. You'd still need to launch them from space since they're a little spicy from a "don't stand downwind" perspective, but unimaginably better than using nukes against pusher.
There are other possible fission options that don't involve detonating actual bombs out the back of the rocket: https://en.wikipedia.org/wiki/Nuclear_propulsion#Spacecraft
I'm a fan of the nuclear lightbulb myself: https://en.wikipedia.org/wiki/Gas_core_reactor_rocket#Closed...
Sometimes I think that while it may be appealing to mine gold or platinum or whatever out of the solar system, what people really need to figure out how to do is mine uranium. While I could advocate with a straight face that maybe we need to freak out a bit less about lifting the occasional few dozen pounds of uranium into orbit, and point out that more radioactive material has already been launched than people realize, it is fair to observe that we probably can't afford to make lifting hundreds of pounds of fission fuel into orbit the sort of routine event it needs to be to really have a space civilization. One of the biggest major issues with any sort of space habitation is access to dense energy sources. You can smooth over a lot of other problems and get a lot more slack in the system if you have a lot of energy available to play with. Part of the challenge with current space technology is that you start out on the very edge of feasibility as it is.
With hindsight being 20/20 and all, it always makes me laugh at how 1950s pro-atomics a lot of things seemed to be. Yes, it was the new, like AI is today so everyone was all about it. Yet there never seemed to be any concerns of the downsides of things like the pesky nuclear waste or fallout. Looking back at films and magazines, the feel of TFA and Fallout are not out of place which is part of what makes them good.
Why say 'brisance' when you could say 'jounce per ounce'.