There are a few more, under
different titles. I remember reading Dyson’s autobiography a couple of years ago and he mentioned his involvement in the research. Absolutely amazing stuff.
There’s a great BBC documentary on this called “To Mars by a Bomb”, highly recommend it. Was one of my first introductions to Freeman Dyson, ended up reading his autobiography as well. Was a remarkable man, and one of my favorite people to listen to.
I spoke to him once at a book signing and asked him about Orion. In summary he said: would it have worked - probably, should it be done - probably not. Although he did make the point that pretty much every big engineering project kills people.
Related, Sprint missile test (anti-ballistic-missile missile). Extremely fast acceleration, you can see in the test footage which is not sped up.
Mass: 7,700 lbs.; Thrust: 650,000 lbs.
Around 100 G of acceleration, reaching Mach 10 within 5 seconds.
"The first stage was exhausted after only 1.2 seconds, but produced 650,000 pounds-force (2,891 kilonewtons) of thrust. On separation, the spent first stage disintegrated due to aerodynamic forces. The second stage fired within 1 to 2 seconds of launch. Interception at an altitude of 1 to 19 miles (1.5 to 30 km) took at most 15 seconds."
https://en.m.wikipedia.org/wiki/Sprint_(missile)
Nuclear tipped SAM isn't too crazy for the time. They were defending against nuclear-armed supersonic bombers and knocking out multiple with one missile was good idea. Early SAMs also weren't that good.
There were lots of nuclear tactical weapons (some bonkers) at the time. Nuclear torpedos. Nuclear anti-submarine rockets. Nuclear artillery shells. Nuclear tactical rockets.
An other quite interesting concept (also a little less "out there" and actually, successfully tested) is the NERVA engine, also linked at the bottom of the article[1].
It uses a nuclear reactor to heat up a single propellant (liquid hydrogen) which then rapidly expands as it goes out the nozzle at the end, resulting in quite high specific impulse and is more efficient than a chemical rocket.
If we want to go really far out in terms of crazy rocket designs, there is also the concept of the nuclear salt-water rocket[2][3].
This one uses enriched plutonium or uranium salts, dissolved in water, inside a neutron-absorbent fuel tank design. The water is pushed out through a pipe, where an uncontrolled chain reaction starts. If it goes fast enough, it explodes right inside the engine bell, pushing the rocket. The proposed design in the original paper is supposed to generate hundreds of gigawatts of thermal power. This is comparable to the Chernobyl reactor #4 when it exploded, but unlike Chernobyl (which only exploded once) or the pulsed Orion engine, it could run continuously. The stuff that flies out of the nozzle easily reaches escape velocity of the solar system.
There's one more: the boring idea of combining a closed, electric-generating nuclear fission system with an (electric-powered) ion engine. Both components being flight tested and not crazy.
There was a classic science fiction story with a twist on this idea; a low tech species was about to be discovered by a more advanced species. And according to the rules of the more advanced species, any planet that wasn't capable of space travel would become a client or vassal, and a planet with space travel would be seen as a peer. The protagonist built a pusher style rocket using an explosive, and launched the lightest person he knew into orbit, who happened to be his girl friend.
I keep thinking this was a Larry Niven story, maybe someone here is familiar?
Edit; another classic story was the novel Footfall by Niven and Pournelle which featured launching the USS Missouri into orbit on an Orion style pusher to battle the invading aliens.
I haven't read that book in 30 years, but the description of experiencing the launch from inside the craft was so succinct and evocative I still think about it from time to time.
> Footfall by Niven and Pournelle which featured launching the USS Missouri into orbit on an Orion style pusher
Yes, there was an Orion. No they didn't launch the USS Missouri. The ship was called Michael and featured, among other crazy weaponry, X-Ray lasers of the SDI type, i.e. some material (ruby?) pumped by a nuke. The nuke would destroy the material, but in the process get it to lase X-Rays. Heck, if you're using nukes for propulsion, might as well do that as well.
Maybe they repurposed the guns for something?
I distinctly remember some dialogue that there was some fairly rough welding of thick steel plates going on, none of the ultra-fine tolerances of traditional rocket engineering.
replying to all... The story you're thinking of is King Davids Spaceship by Jerry Pournelle. It IS a co-dominion story (so same universe as The Mote in Gods Eye w/Larry Niven)
A few other uses of Orion in fiction that I am aware of:
The Ship 'Michael' (as in avenging angel) from Footfall (Again by Niven and Pournelle).
And the ship from Orion shall rise by Paul Anderson.
A CBC Miniseries featuring a (faked) Orion derived interstellar ark supposedly launched in the 60's and the people that have been living on it for almost 40 years.
Project Orion is a really bad idea. I guess it could be a good idea in specific situation where have to get a lot of mass off the planet and don't care about the effects.
Problem one is that detonating a series of nuclear bombs in the atmosphere. The first couple are close to the ground and produce local fallout, the higher ones produce global fallout.
Problem two is that detonating nuclear bombs in space causes EMP. That doesn't destroy electronics on ground as thought but will knock out the electrical grid.
The extra radiation will knock out satellites in space.
There is interstellar Orion, Project Daedalus, but that is quite different with inertial confinement fusion and magnetic fields directing the exhaust.
The problem with that is Orion is that it is heavy. It only makes sense when launching the whole thing from the ground. Orion has been proposed for interplanetary propulsion since it is pretty efficient. But would need to be convertible from ground-launch to space propulsion. Nuclear rockets are pretty good and safer to launch.
The other problem is that nuclear weapons are expensive. Something like Davy Crockett is 2kg of plutonium, and mid-sized Orion would use 800 to get to orbit. Plutonium is $4000/g which means $6.4 billion to launch Orion. Orion that puts 1600t in orbit. Or 10 Starships which is less as disposable rockets and way less if reuasable.
In 1965 the Atomic Energy Commission put the cost of plutonium 239 at $10/gram, which by simple consumer price indexing (only a rough guide, admittedly) would make it $96/gram today.
See Table I in this publication "Values In Spent Fuel From Power Reactors":
At $96 per gram instead of $4000, that's a much more attractive $154 million to put 1600 tons in orbit. Uranium enrichment costs have fallen greatly since the 1960s as centrifuges have replaced gaseous diffusion, so uranium-fueled units would probably cost less (despite the greater mass of uranium required).
I'd say that the main modern problems of a terrestrially launched Orion are treaty violations and giving a plausible cover for nations to again pursue developing "peaceful" nuclear explosives.
Not as "spicy" an idea as the Nuclear saltwater rocket however, which instead of discrete bombs involves dissolving a load of bomb-grade fissiles into water and then ejecting them out a conventional rocket engine, with the idea the solution goes critical somewhere in the vincinity of the exhaust nozzle. Now if you're thinking "Does that replace singular discrete nuclear explosions with a continual nuclear explosion shrouded in an expanding cloud of radioactive superheated steam?", the answer is yes, yes it does.
Weirdest thing is the design doesn't actually have as much potential ISP as a pulsed detonation system like an Orion, despite being a bonafide torchship. Go figure
IIRC the estimate was that the extra radiation from a launch would kills tens of people per launch, not thousands. Still not great (especially if you are one of those victims), but not as much as you might expect.
There is a Kerbal Space Program mod [1] that adds this to the game. It is hysterically fun to use because it is insanely unbalanced compared to normal space flight requirements. Want to change your orbit 180deg and fly backwards? No problem. Goto any planet the "direct" route? Sure, why not. Take off from the launch pad so fast you'll think the game broke? Not a problem - The Kerbal's don't worry about a little fallout.
No idea how this would ever actually work in reality for manned spaceflight. For unmanned it seems relatively doable (ignoring the entire cost of getting it off the ground and into space first). But for a manned mission? Being subject to 2-4g is one thing, but to have it happen regularly... like a jackhammer almost? Sounds like a really bad trip. You could not do anything while that engine was firing (not that it'd be easy to do something under 2g constant acceleration) without risk of being in the wrong place/position at the wrong time. I don't know what the long terms effects of repeated, assumingly rapid, 2-4g pulsing is on the human body.... but I'd guess it falls under "can't be anything good" category.
Based on the amount of time a Kerbal can survive orbiting the sun in their barely-shielded capsules, I am inclined to think that they are immune to radiation damage, like tardigrades.
Project Orion uses a pusher plate mounted on giant springs to spread out the force of each explosion. If the system is designed correctly it should result in constant acceleration.
So there are ways to make this interesting in the game and bring it back to balance. Some recommendations:
- The USI pulse nukes are expensive. Play on career mode so you are cash constrained and have to rigorously plan for their build, use, and refueling.
- Roleplay not using them anywhere near low home-planet orbit for fallout reasons. I.e. the ship is built and is parked in a shipyard in Cislunar space and kerbonauts must ride an intermediary shuttle vessel to crew it.
- Use a life support pack and planet mods that add interplanetary destinations. Having your kerbonauts on a nuke ship around an extrasolar planetary body far away from home with limited supplies will add plenty to the mix.
This was supposed to be in Kerbal Space Program 2, and you can see an early version of it in some of the promotional materials. Time will tell when it makes its way into the game.
There is also a book called Project Orion: The True Story of the Atomic Spaceship. It's still sitting on my shelf, but I don't remember it being a particularly inspiring read because it was tailored towards interstellar travel when we hadn't even reached Mars yet.
39 comments
[ 0.24 ms ] story [ 36.1 ms ] threadInterstellar nuclear-powered transport (1968) [pdf] - https://news.ycombinator.com/item?id=28132756 - Aug 2021 (34 comments) - thanks antondd!
Orion Project [pdf] - https://news.ycombinator.com/item?id=22691219 - March 2020 (1 comment)
Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf] - https://news.ycombinator.com/item?id=12705705 - Oct 2016 (99 comments)
Project Orion (nuclear propulsion) - https://news.ycombinator.com/item?id=9025611 - Feb 2015 (11 comments)
Project Orion (nuclear propulsion) - https://news.ycombinator.com/item?id=3019627 - Sept 2011 (1 comment)
Project Orion is one of the stupidest, most wonderful ideas ever conceived in America. - https://news.ycombinator.com/item?id=261348 - July 2008 (6 comments)
That's less than I expected - are there other threads?
There are a few more, under different titles. I remember reading Dyson’s autobiography a couple of years ago and he mentioned his involvement in the research. Absolutely amazing stuff.
https://youtu.be/xYoLcJuBtOw
I spoke to him once at a book signing and asked him about Orion. In summary he said: would it have worked - probably, should it be done - probably not. Although he did make the point that pretty much every big engineering project kills people.
Mass: 7,700 lbs.; Thrust: 650,000 lbs.
Around 100 G of acceleration, reaching Mach 10 within 5 seconds.
"The first stage was exhausted after only 1.2 seconds, but produced 650,000 pounds-force (2,891 kilonewtons) of thrust. On separation, the spent first stage disintegrated due to aerodynamic forces. The second stage fired within 1 to 2 seconds of launch. Interception at an altitude of 1 to 19 miles (1.5 to 30 km) took at most 15 seconds." https://en.m.wikipedia.org/wiki/Sprint_(missile)
https://youtu.be/kvZGaMt7UgQ
There were lots of nuclear tactical weapons (some bonkers) at the time. Nuclear torpedos. Nuclear anti-submarine rockets. Nuclear artillery shells. Nuclear tactical rockets.
https://en.wikipedia.org/wiki/A-135_anti-ballistic_missile_s...
It uses a nuclear reactor to heat up a single propellant (liquid hydrogen) which then rapidly expands as it goes out the nozzle at the end, resulting in quite high specific impulse and is more efficient than a chemical rocket.
If we want to go really far out in terms of crazy rocket designs, there is also the concept of the nuclear salt-water rocket[2][3].
This one uses enriched plutonium or uranium salts, dissolved in water, inside a neutron-absorbent fuel tank design. The water is pushed out through a pipe, where an uncontrolled chain reaction starts. If it goes fast enough, it explodes right inside the engine bell, pushing the rocket. The proposed design in the original paper is supposed to generate hundreds of gigawatts of thermal power. This is comparable to the Chernobyl reactor #4 when it exploded, but unlike Chernobyl (which only exploded once) or the pulsed Orion engine, it could run continuously. The stuff that flies out of the nozzle easily reaches escape velocity of the solar system.
[1] https://en.wikipedia.org/wiki/NERVA?useskin=vector
[2] https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket?uses...
[3] Obligatory Scott Manley video: https://www.youtube.com/watch?v=cvZjhWE-3zM
It's probably a great choice for once you're already in space, where being able to apply even very small thrusts nearly-continuously really adds up.
I keep thinking this was a Larry Niven story, maybe someone here is familiar?
Edit; another classic story was the novel Footfall by Niven and Pournelle which featured launching the USS Missouri into orbit on an Orion style pusher to battle the invading aliens.
However, 'Footfall' by Niven and Pournelle does have an Orion, as does Invisible Sun, by Charles Stross.
Nothing obvious in [0]
[0] https://en.wikipedia.org/wiki/List_of_stories_featuring_nucl...
"God was knocking and he wanted in bad."
Yes, there was an Orion. No they didn't launch the USS Missouri. The ship was called Michael and featured, among other crazy weaponry, X-Ray lasers of the SDI type, i.e. some material (ruby?) pumped by a nuke. The nuke would destroy the material, but in the process get it to lase X-Rays. Heck, if you're using nukes for propulsion, might as well do that as well.
Maybe they repurposed the guns for something?
I distinctly remember some dialogue that there was some fairly rough welding of thick steel plates going on, none of the ultra-fine tolerances of traditional rocket engineering.
A few other uses of Orion in fiction that I am aware of:
The Ship 'Michael' (as in avenging angel) from Footfall (Again by Niven and Pournelle).
And the ship from Orion shall rise by Paul Anderson.
A CBC Miniseries featuring a (faked) Orion derived interstellar ark supposedly launched in the 60's and the people that have been living on it for almost 40 years.
Problem one is that detonating a series of nuclear bombs in the atmosphere. The first couple are close to the ground and produce local fallout, the higher ones produce global fallout.
Problem two is that detonating nuclear bombs in space causes EMP. That doesn't destroy electronics on ground as thought but will knock out the electrical grid. The extra radiation will knock out satellites in space.
There is interstellar Orion, Project Daedalus, but that is quite different with inertial confinement fusion and magnetic fields directing the exhaust.
But those are the least of the concerns.
The other problem is that nuclear weapons are expensive. Something like Davy Crockett is 2kg of plutonium, and mid-sized Orion would use 800 to get to orbit. Plutonium is $4000/g which means $6.4 billion to launch Orion. Orion that puts 1600t in orbit. Or 10 Starships which is less as disposable rockets and way less if reuasable.
See Table I in this publication "Values In Spent Fuel From Power Reactors":
https://www.osti.gov/servlets/purl/4618921
At $96 per gram instead of $4000, that's a much more attractive $154 million to put 1600 tons in orbit. Uranium enrichment costs have fallen greatly since the 1960s as centrifuges have replaced gaseous diffusion, so uranium-fueled units would probably cost less (despite the greater mass of uranium required).
I'd say that the main modern problems of a terrestrially launched Orion are treaty violations and giving a plausible cover for nations to again pursue developing "peaceful" nuclear explosives.
Weirdest thing is the design doesn't actually have as much potential ISP as a pulsed detonation system like an Orion, despite being a bonafide torchship. Go figure
https://en.m.wikipedia.org/wiki/Nuclear_salt-water_rocket
There's too many "Orion" things out there to make it clear that this specific one is about nuclear propulsion.
No idea how this would ever actually work in reality for manned spaceflight. For unmanned it seems relatively doable (ignoring the entire cost of getting it off the ground and into space first). But for a manned mission? Being subject to 2-4g is one thing, but to have it happen regularly... like a jackhammer almost? Sounds like a really bad trip. You could not do anything while that engine was firing (not that it'd be easy to do something under 2g constant acceleration) without risk of being in the wrong place/position at the wrong time. I don't know what the long terms effects of repeated, assumingly rapid, 2-4g pulsing is on the human body.... but I'd guess it falls under "can't be anything good" category.
[1] https://umbraspaceindustries.github.io/UmbraSpaceIndustries/
- The USI pulse nukes are expensive. Play on career mode so you are cash constrained and have to rigorously plan for their build, use, and refueling.
- Roleplay not using them anywhere near low home-planet orbit for fallout reasons. I.e. the ship is built and is parked in a shipyard in Cislunar space and kerbonauts must ride an intermediary shuttle vessel to crew it.
- Use a life support pack and planet mods that add interplanetary destinations. Having your kerbonauts on a nuke ship around an extrasolar planetary body far away from home with limited supplies will add plenty to the mix.