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 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.
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.
Argentina on two steaks a day is quite possibly one of the best pieces of humorous writing, full stop. In my opinion at least, it should be regarded in company with Mark Twain and Jonathan Swift, though maybe not at the head of that particular table.
That post is single-handedly responsible for me going to Buenos Aires.
(Well that and a Qatar Airways misprice a couple of years back; but I would not have been motivated to jump on that occasion if I had not read the post.)
Oh! I actually thought I tried to be really careful to get that right and somehow still didn't see I'd transposed the j and c. Definitely no harm intended!
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.
Currently, the most reliable rockets are maybe 99% reliable but certainly not 99.9%. If you are trying to send nuclear material to space, you have to account for the possibility that
* The rocket blows up on the launchpad
* The rocket gets you part way up, then blows up during ascent
* The rocket fails before orbital insertion, and your nuclear payload re-enters the atmosphere at near-orbital velocity
In all of those cases, you need to have enough shielding to avoid spreading nuclear waste over a very large area -- that adds a lot of mass. And everyone whose jurisdiction you're launching over needs to trust you have enough shielding. And in the case where it fails during orbit insertion and re-enters the atmosphere, you don't have a lot of control on where the nuclear materials end up, which has proliferation issues.
> In all of those cases, you need to have enough shielding to avoid spreading nuclear waste over a very large area -- that adds a lot of mass.
Conservatively it might add an order of magnitude, and likely less. This still renders future reusable launchers much cheaper per kg of spent fuel than reprocessing would be, unless you are projecting very large improvements in the cost of reprocessing.
You might object current launchers aren't cheap enough, but I wasn't proposing doing this right now with current launchers, so that would be a strawman objection.
That $1000/kg figure is reprocessing something like 10kg of material to get 1kg of enriched material.
Current costs to launch a kg to orbit are something like $2,000-$6,000.
If we're comparing it to you enriched amount, you'd have to launch 10kg, which means you'd have to hit $100/kg launch costs to break even. I'm not convinced that will ever be possible; that's on the order of a first class arline ticket for a 50kg person.
This also doesn't consider what you're getting for launching it into orbit. If the 100 year risk of a casket leaking is (say) x mrads into the environment, you're going to have to consider what the equivalent of vaporizing all of it into the atmosphere in the event of a failed launch is. the fallout (hah) from a failed launch of nuclear waste seems magnitudes more catastrophic than having the same stuff slowly leaking in the middle of a desert cave.
> Current costs to launch a kg to orbit are something like $2,000-$6,000.
This is false. Launch on Falcon 9 is under $1K/kg.
Moreover, current launch costs are just a milestone toward future launch costs, which promise to me much lower. Ultimately launch will be a few times the cost of propellant (just like air travel), so $10/kg is a reasonable expectation.
> vaporizing in the atmosphere
How does this happen? Launch explosion? That doesn't vaporize an armored container. Entry from near-orbital speed? Also survivable passively.
The result of an accident will be tracking down the armored canister(s), cleaning up any local impact fragments, and prepared the stuff for another launch.
The armored canister doesn't have to be sent beyond LEO, so it could be reused, and doesn't impose a mass penalty on that beyond-LEO transport system.
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.
I think there were big reflectors in the book, but it's been years since I read it. It's the sail that would need to be toroidal and huge. I guess the better point is that, if you can always maneuver the bombs at EXACTLY the right point relative to the sail and they are are perfectly uniformly spherical, and you can orient the sail perfectly before hand, then you can balance on top of the nuclear pin and don't need a stabilizing concentric force.
This worked for Snow Crash - felt like I went on a theme park ride, got to the end of it, and hopped off still buzzing. Doesn't work so well for something less tongue in cheek.
Strong agree. I was especially disappointed because it felt like he was dropping breadcrumbs all through the book and then... Nah, none of that foreshadowing mattered. The central tension of the book is handled by an off-screen deus ex machina, actually, everybody go home.
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.
mc32 | a day ago
dylan604 | a day ago
showerst | a day ago
jerf | a day ago
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.
jebarker | a day ago
troybetz | a day ago
https://idlewords.com/2006/04/argentina_on_two_steaks_a_day....
https://idlewords.com/2014/07/sana_a.htm
simonw | a day ago
Also a big fan of https://idlewords.com/2010/03/scott_and_scurvy.htm
jaggederest | a day ago
klausa | 22 hours ago
(Well that and a Qatar Airways misprice a couple of years back; but I would not have been motivated to jump on that occasion if I had not read the post.)
titanomachy | a day ago
alexjplant | a day ago
tclancy | a day ago
jimt1234 | 18 hours ago
tclancy | 17 hours ago
variaga | 21 hours ago
https://m.youtube.com/watch?v=YgDPrhV8z5s
selimthegrim | 23 hours ago
klausa | 22 hours ago
jebarker | 19 hours ago
MarkusQ | a day ago
You don't say.
nicbou | a day ago
GoatOfAplomb | a day ago
idlewords | a day ago
foobarian | a day ago
jcs | a day ago
idlewords | a day ago
jaggederest | a day ago
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
pfdietz | a day ago
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.
IAmBroom | a day ago
Congrats; you have come up with a way to make nuclear waste disposal 100x more dangerous and 1000x more expensive!
pwg | a day ago
https://en.wikipedia.org/wiki/Space_1999
polynomial | a day ago
pfdietz | a day ago
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.
gavinsyancey | 22 hours ago
* The rocket blows up on the launchpad
* The rocket gets you part way up, then blows up during ascent
* The rocket fails before orbital insertion, and your nuclear payload re-enters the atmosphere at near-orbital velocity
In all of those cases, you need to have enough shielding to avoid spreading nuclear waste over a very large area -- that adds a lot of mass. And everyone whose jurisdiction you're launching over needs to trust you have enough shielding. And in the case where it fails during orbit insertion and re-enters the atmosphere, you don't have a lot of control on where the nuclear materials end up, which has proliferation issues.
pfdietz | 7 hours ago
Conservatively it might add an order of magnitude, and likely less. This still renders future reusable launchers much cheaper per kg of spent fuel than reprocessing would be, unless you are projecting very large improvements in the cost of reprocessing.
You might object current launchers aren't cheap enough, but I wasn't proposing doing this right now with current launchers, so that would be a strawman objection.
hex4def6 | 20 hours ago
Current costs to launch a kg to orbit are something like $2,000-$6,000.
If we're comparing it to you enriched amount, you'd have to launch 10kg, which means you'd have to hit $100/kg launch costs to break even. I'm not convinced that will ever be possible; that's on the order of a first class arline ticket for a 50kg person.
This also doesn't consider what you're getting for launching it into orbit. If the 100 year risk of a casket leaking is (say) x mrads into the environment, you're going to have to consider what the equivalent of vaporizing all of it into the atmosphere in the event of a failed launch is. the fallout (hah) from a failed launch of nuclear waste seems magnitudes more catastrophic than having the same stuff slowly leaking in the middle of a desert cave.
pfdietz | 18 hours ago
This is false. Launch on Falcon 9 is under $1K/kg.
Moreover, current launch costs are just a milestone toward future launch costs, which promise to me much lower. Ultimately launch will be a few times the cost of propellant (just like air travel), so $10/kg is a reasonable expectation.
> vaporizing in the atmosphere
How does this happen? Launch explosion? That doesn't vaporize an armored container. Entry from near-orbital speed? Also survivable passively.
The result of an accident will be tracking down the armored canister(s), cleaning up any local impact fragments, and prepared the stuff for another launch.
The armored canister doesn't have to be sent beyond LEO, so it could be reused, and doesn't impose a mass penalty on that beyond-LEO transport system.
psadri | a day ago
kurthr | a day ago
https://www.centauri-dreams.org/2024/04/17/medusa-deep-space...
sushisource | 22 hours ago
kurthr | 16 hours ago
samatman | a day ago
mayoff | a day ago
Chu4eeno | a day ago
lern_too_spel | a day ago
p1necone | 21 hours ago
jaggederest | a day ago
ezekg | a day ago
ahartmetz | 13 hours ago
cfiggers | 22 hours ago
Incredible ideas. Really, really lousy ending.
PopAlongKid | a day ago
variaga | 21 hours ago
woadwarrior01 | a day ago
https://en.wikipedia.org/wiki/NERVA
https://en.wikipedia.org/wiki/RD-0410
NoImmatureAdHom | a day ago
gonight | 20 hours ago
helterskelter | 19 hours ago