Project Orion: to Mars by 1965, in a spaceship propelled by nuclear bombs.

February 1, 2010 2:34 PM

Ted Taylor, physicist, nuclear scientist, and designer of the deceptively tiny Davy Crockett nuclear recoilless rifle, is not quite as famous as one of his other projects: nuclear spacecraft propulsion. Project Orion was intended as an interplanetary (and eventually interstellar) vehicle which could achieve Earth orbit with a series of 800 nuclear explosions, each detonated about a second after the other below the spacecraft. It would propel itself through space in a similar fashion, carrying many orders of magnitude more mass than chemical rockets such as the Saturn which would ultimately take men to the moon. Taylor and others intended a mission to Mars by 1965, but the Partial Test Ban Treaty of 1963 destroyed all hope to see Orion take flight. For the interested, "The Curve of Binding Energy" goes into much more detail, including the U.S. Air Force's plan to turn Orion into a nuclear space battleship (!). A youtube video of an Orion concept test using conventional explosives is here (flight footage begins around 0:23).
posted by edguardo (56 comments total)

A related previous post.
posted by wierdo at 2:40 PM on February 1, 2010 [1 favorite]

One of the best parts of My American Journey was Colin Powell's memoirs of serving in West Germany. He hated the damn nuclear artillery, hated having to "war game" with them, and was happy to see them taken off the front lines.
posted by Cool Papa Bell at 2:40 PM on February 1, 2010

The Orion concept found fictional life in Heinlein and Pournelle's novel Footfall.
posted by Guy_Inamonkeysuit at 2:44 PM on February 1, 2010

Ok so you can accelerate dropping bombs out the back. How do you decelerate? Shoot bombs out the front and fly into the shockwave?
posted by PenDevil at 2:45 PM on February 1, 2010 [1 favorite]

And also in Anathem
posted by Paragon at 2:45 PM on February 1, 2010 [2 favorites]

He hated the damn nuclear artillery, hated having to "war game" with them, and was happy to see them taken off the front lines.

One of the ironies of the cold war is how much the military hated nuclear weapons, and on both sides! It seems that armies prefer to wage wars and not have there roles relegated to restarting civilization after a few politicians push a button. Of course their love of cold war level budgets is another thing, but as a whole it isn't too much fun to have a war that's all over in 20 minutes.

Project Orion is cool in a field where cool things stopped after we landed on the moon. Unfortunately launching nuclear rockets from barges in the Arctic that may, may only incur one cancer fatality per launch is not really the greenest thing -- and those were numbers from the 60s. Not to mention what would happen if the pusher plate exploded and you have 80 perfectly spaced nuclear detonations happening all at once. I'm sure you could probably build in a whole bunch of safety devices, but the launch that fails is the last launch that'll ever happen.

Of course Project Orion was happening at a time when clean fusion explosions were at least thought to be right around the corner, now we're really nowhere closer to fusion than we were for some time. Sure our science knowledge may have increased, but as a practical engineering matter, for the forseeable future dirty, radioactive explosions are the only thing around.
posted by geoff. at 2:47 PM on February 1, 2010 [2 favorites]

Ok so you can accelerate dropping bombs out the back. How do you decelerate? Shoot bombs out the front and fly into the shockwave?

Turn your spacecraft around its center of mass so your shielded pusher plate is facing in the direction of your initial acceleration. Then shoot bombs out the "front." :)
posted by edguardo at 2:51 PM on February 1, 2010 [1 favorite]

Woudln't that continually bath the ship in radiation. When it's accelerating it's moving away from the explosion. Decelerating that way means flying through the detrius of a nucelar explosion every few seconds.
posted by PenDevil at 2:55 PM on February 1, 2010

Woudln't that continually bath the ship in radiation. When it's accelerating it's moving away from the explosion. Decelerating that way means flying through the detrius of a nucelar explosion every few seconds.

If that sounds bad to you, you'll hate to hear that some people on the project apparently wanted to land the thing on other planets.

Then, you know, get out and muck about in the blast crater, I guess.
posted by edguardo at 2:57 PM on February 1, 2010 [1 favorite]

There was an interesting BBC Four documentary on it . Originally it was envisioned as a peaceful mission to the outer planets and gradually got took over by the military. The planned idea was also insanely large, due to the fact that unlike conventional spacecraft there's more of a problem with it being too light (i.e. so the acceleration is survivable) than too heavy.

For a quicker introduction see this TED talk on Orion
posted by Erberus at 3:05 PM on February 1, 2010 [2 favorites]

Wait, is the plan to start the detonations on Earth, or do they not start until the thing has left the atmosphere?

Detonating a nuclear device 800 times in the atmosphere? Bad idea jeans.
posted by spikeleemajortomdickandharryconnickjrmints at 3:11 PM on February 1, 2010

My God, I love Project Orion. Always have.

Even one of the smaller proposed vehicles would carry an entire lunar base in one trip. And it'd be a real spaceship, of rivets and steel plate instead of some gossamer graphite and ceramic dealie that gets fatally damaged by pieces of it's own insulation foam.

I wonder if the Chinese have the cojones to let the rest of the world just wake up and learn they're off to Mars, back in a few months.

It's not like they signed the Partial Test Ban Treaty or anything.
posted by codswallop at 3:12 PM on February 1, 2010 [2 favorites]

Wait, is the plan to start the detonations on Earth, or do they not start until the thing has left the atmosphere?

Detonating a nuclear device 800 times in the atmosphere? Bad idea jeans.

Yep, on Earth, although explosion #1 was supposed to be conventional for "environmental reasons." :)

The yields of the bombs varied (they increased with altitude I think), but the total yield to orbit was I think 10 megatons, which was equivalent to some singular bombs being detonated at the time.

Freeman Dyson estimated just ~1 death from cancer per launch. :P
posted by edguardo at 3:15 PM on February 1, 2010

Here's the BBC documentary at veoh.com
posted by codswallop at 3:17 PM on February 1, 2010

Not to mention what would happen if the pusher plate exploded and you have 80 perfectly spaced nuclear detonations happening all at once. I'm sure you could probably build in a whole bunch of safety devices, but the launch that fails is the last launch that'll ever happen.

Yeah, considering we never really ironed out all of the bugs in the space shuttle after 30 years, this does seem to be a disaster that's guaranteed to happen eventually. Irradiating a good chunk of the (melting) polar ice would have a lot unintended consequences that we weren't thinking about in the 50/60s.
posted by doctor_negative at 3:18 PM on February 1, 2010

Turn your spacecraft around its center of mass so your shielded pusher plate is facing in the direction of your initial acceleration. Then shoot bombs out the "front." :)

It's a heckuva lot easier to press the 'Hyperspace' button. The only (albeit major) risk is that you might end up in the path of an oncoming asteroid.
posted by prinado at 3:18 PM on February 1, 2010 [1 favorite]

It's a heckuva lot easier to press the 'Hyperspace' button. The only (albeit major) risk is that you might end up in the path of an oncoming asteroid.

Asteroids which can, on the other hand, offer good cover from nearby Imperial Star Destroyers.
posted by edguardo at 3:23 PM on February 1, 2010

The thing I love the most about the wiki on the Fat Man Mini-nuke Davy Crockett nuclear recoilless rifle, is implications suggested by the first couple of lines.

The first thing you see is the picture and you think "Oh, that looks like a bad idea. there is no way that launcher could make that projectile go far enough away from me to make me comfortable shooting it."

The next thing you see is the Contents:

# 1 Development
# 2 Survivors

Which, regardless of what it actually links to, strongly suggests that 1.) there was a development process to work out the kinks of lobbing a small, yet robust, nuclear device with what is not too far removed from an RPG, and 2.) here is a list of the people who survived this testing.

Awesome.
posted by quin at 3:34 PM on February 1, 2010 [5 favorites]

The first thing you see is the picture and you think "Oh, that looks like a bad idea. there is no way that launcher could make that projectile go far enough away from me to make me comfortable shooting it."

That's an interesting pic. The only thing that's missing is a stencilled "ACME" on the side of it - and a very eager coyote on top of it.
posted by panboi at 3:59 PM on February 1, 2010 [3 favorites]

I want two branches of government, one that's really good at insuring the welfare of its citizens and promoting a healthy, productive society -- and the other that spends all the time making nuclear rockets.
posted by RobotVoodooPower at 4:21 PM on February 1, 2010 [3 favorites]

The thing I love the most about the wiki on the Fat Man Mini-nuke Davy Crockett nuclear recoilless rifle...

The U.S. Army feared the Soviet Super Mutant Behemoth.

I want two branches of government, one that's really good at insuring the welfare of its citizens and promoting a healthy, productive society -- and the other that spends all the time making nuclear rockets.

Where can I register for your party? :D
posted by edguardo at 4:50 PM on February 1, 2010

Ted Taylor is a really interesting figure. He is the guy who single-handedly redirected us from building bigger, bigger, bigger bombs to asking exactly what you want the bomb to do, and seeing if you can optimize for it, treating it as an instrument calibrated to get a certain result instead of a generic instrument for blowing shit up. This is the main reason it's the Russians who built the biggest bomb ever, the Tsara Bomba; by the time they did that we weren't thinking along those lines any more. Instead, we had figured out that with better accuracy we could achieve the same kill rate with a 300 lb 200 kt-yield bomb that had been possible with thirty ton megaton-yield bombs a few years before, and that meant we could mount six of the damn things on one ICBM. Yay technology.
posted by localroger at 5:02 PM on February 1, 2010 [1 favorite]

Footfall was set in Bellingham. Where George Dyson, son of Freeman and author of the book, Project Orion, lives. Coincidence or .... ?

Maybe not because Pournelle had a survival retreat not too far away from Bham, too.

George is a cool dude.
posted by warbaby at 5:07 PM on February 1, 2010

Which, regardless of what it actually links to, strongly suggests that 1.) there was a development process to work out the kinks of lobbing a small, yet robust, nuclear device with what is not too far removed from an RPG, and 2.) here is a list of the people who survived this testing.

It's a list of surviving Davy Crockett casings stored in various museums, not a list of people who survived testing it.
posted by L.P. Hatecraft at 5:08 PM on February 1, 2010

I prefer the relatively safe and efficient Project Pluto.
posted by mccarty.tim at 5:09 PM on February 1, 2010

Oh, and Ted Taylor worked on a lot of sustainable energy projects. Like the "blower door" that everybody uses to test how weather-tight houses are. And snow storage for summer air conditioning.

Ted was a cool dude as well.
posted by warbaby at 5:10 PM on February 1, 2010

@localroger
It always makes me feel warm and fuzzy when I know the scientists have come up with more efficient bombs.
posted by mccarty.tim at 5:11 PM on February 1, 2010

> Ok so you can accelerate dropping bombs out the back. How do you decelerate? Shoot bombs out the front and fly into the shockwave?

Turn your spacecraft around its center of mass so your shielded pusher plate is facing in the direction of your initial acceleration. Then shoot bombs out the "front." :)
posted by edguardo at 2:51 PM on February 1

Woudln't that continually bath the ship in radiation. When it's accelerating it's moving away from the explosion. Decelerating that way means flying through the detritus of a nucelar explosion every few seconds.
posted by PenDevil at 2:55 PM on February 1

The detritus would be launched at a faster velocity, so it would be accelerating forward from the vehicle. You don't fly into it because it's flying faster than you are. It's the same problem as starting, actually. You're starting from zero velocity in a Newtonian reference frame.

However, I'd be worried if you go into orbit, what happens if the deceleration debris comes back around a few orbits later and THEN you run into it.
posted by Araucaria at 5:44 PM on February 1, 2010 [1 favorite]

Decelerating this thing wouldn't be any more difficult then decelerating a rocket.

Not to mention what would happen if the pusher plate exploded and you have 80 perfectly spaced nuclear detonations happening all at once. I'm sure you could probably build in a whole bunch of safety devices, but the launch that fails is the last launch that'll ever happen.

Nuclear bombs aren't like regular bombs, they have to be set off in a very precise way.
posted by delmoi at 5:47 PM on February 1, 2010 [1 favorite]

Ok so you can accelerate dropping bombs out the back. How do you decelerate? Shoot bombs out the front and fly into the shockwave?

Shockwave? In space?
posted by schwa at 5:48 PM on February 1, 2010

Oh, and if you wanted too you could launch this thing in pieces and assemble it in orbit (or on the moon!) and launch it from there.
posted by delmoi at 5:49 PM on February 1, 2010

Here's some YouTube footage of a Davy Crockett test
posted by KokuRyu at 6:13 PM on February 1, 2010

Shockwave? In space?

Sure. You set off a bomb in space, you get a wave of hot, high-pressure gas expanding out into the vacuum. When the front of that wave hits the big flat shielded plate on the back of the ship, it imparts some of its kinetic energy to the ship itself, and that's what changes the ship's velocity.
posted by nebulawindphone at 6:23 PM on February 1, 2010 [1 favorite]

On a trip to Yucca Mountain about 10 years ago we drove past some smallish rockets sitting on what looked like landing pads. Our guide (one of the research scientists) mentioned something about them being related to the nuclear powered rocket program and made a joke about "one of them blowing up in the atmosphere" and the problems that would create. I always thought he was joking....
posted by Big_B at 6:31 PM on February 1, 2010

They are not just nuclear bombs. They are actually nuclear shaped charges, with 80% of the blast aimed at the rocket's pusher plate.
Details here.
posted by Nyrath at 6:54 PM on February 1, 2010

Sure. You set off a bomb in space, you get a wave of hot, high-pressure gas expanding out into the vacuum.

Well that's not really a good definition of a shockwave. More like, well, shrapnel. Shockwaves would need to be transmitted through a medium no?

Anyway, hairs split.
posted by schwa at 7:28 PM on February 1, 2010

The dynamics are going to be slightly different, but you still have in essence a sudden boundary between low and high pressure, in space, though, the low pressure is zero.
posted by Zalzidrax at 7:56 PM on February 1, 2010

L.P. Hatecraft: "Davy Crockett casings"

I hear they make for an excellent longpork sausage.
posted by idiopath at 8:11 PM on February 1, 2010

A few clarifications : Orion used fairly small bombs that did not leave much fall out, although the full launch sequence was similar to individual atmospheric weapon's tests. These were "shaped" to direct most of the energy at the pusher plate. Energy is transported by plasma and radiation, not shrapnel. The pusher plate itself would be protected from the explosions by continually oiling it with graphite. Shrapnel would only occur from bomb failure and might even damage the pusher plate.
posted by jeffburdges at 8:21 PM on February 1, 2010 [1 favorite]

Ah, yeah, it hadn't even occurred to me that the radiation itself would be transmitting a significant amount of force — but now that you mention it, that makes sense. Way cool.
posted by nebulawindphone at 8:26 PM on February 1, 2010

Araucaria wrote: "However, I'd be worried if you go into orbit, what happens if the deceleration debris comes back around a few orbits later and THEN you run into it."

That's what the shielded pusher plate is for.

The thing is that fusion bombs are actually relatively clean. If you can shield yourself from the initial gamma ray burst, everything else dissipates in short order. The reason why bombs create so much fallout on earth is because there's a lot of stuff that gets irradiated and becomes radioactive. In space, that's not really an issue, as you only have the bomb parts (and a few molecules from the surface of your pusher plate) getting irradiated.

As I recall, though, in space the energy imparted into the vessel is just the radiation (alpha and beta particles plus the gamma rays) providing the force. There's not much in the way of a "shockwave" as one would traditionally conceive it.

It's pretty much the same thing as a solar sail, only with big things that go boom providing the high energy particles to do the pushing rather than the relatively weak solar wind.

This sort of technology would be great for launching interplanetary missions from the Moon.
posted by wierdo at 8:51 PM on February 1, 2010 [1 favorite]

Shit, I forgot to mention that fission bombs do indeed create a lot of crappy long-lived isotopes, and since we can only start a fusion reaction with a fission bomb, there's always at least a little bit of that junk floating around in the debris, but it doesn't take much of a primary to provide the energy to set off the fusion part of the bomb, so you get a lot of energy out of only a little fission.
posted by wierdo at 8:54 PM on February 1, 2010

The Orion concept found fictional life in Heinlein and Pournelle's novel Footfall.

Niven and Pournelle, actually.
posted by DreamerFi at 11:19 PM on February 1, 2010

I read about Project Orion, and I thought: "What a fantastically stupid idea."
Then I read about the Davy Crockett...

From the Wikipedia page:

"The Davy Crockett could be launched from either of two launchers: the 4-inch (102 mm) M28, with a range of about 1.25 mi (2 km), or the 6-in (155 mm) M29, with a range of 2.5 mi (4 km)."

"Both recoilless guns proved to have poor accuracy in testing, so the shell's greatest effect would have been its extreme radiation hazard. Even at a low yield setting, the M-388 would produce an almost instantly lethal radiation dosage (in excess of 10,000 rem) within 500 feet (150 m), and a probably fatal dose (around 600 rem) within a quarter mile (400 m)."

Not a weapon to be fired against the wind, then...
posted by Skeptic at 12:58 AM on February 2, 2010

Footfall has a delightful description of actually flying in an Orion ship (quoted from memory): "God was knocking, and he wanted in bad."
posted by bouvin at 4:23 AM on February 2, 2010

wierdo, if you were to build a "fusion bomb" you wouldn't call it that. You'd call it a neutron bomb. At least, that's what the people who build them call them.

What we call H-bombs actually derive about 80% of their energy output by using the neutron flux from the fusion reaction to fission depleted uranium. The whole spin about them being clean as morning flowers and harnessing the power of the Sun is, let me think, there's a word for it, oh yes it's a big fat lie. Hydrogen bombs are extremely dirty and their only advantage over regular fission bombs is that they make a bigger bang with less enriched material.
posted by localroger at 5:20 AM on February 2, 2010

nebulawindphone, the radiation doesn't actually transmit significant force. This is another bit of misdirection that was meant to keep people from figuring out how H-bombs really work back before Howard Morland spilled the beans. (If you're curious, google the phrase "Teller-Ulam".) What actually happens is that the radiation is used to flash plastic foam into plasma, and the plasma exerts the force. The trick in an H-bomb is that the radiation pulse that flashes the foam into plasma moves out at the speed of light, while the shock wave from the fission trigger is significantly slower. The second stage of the H-bomb must be compressed by the foam plasma and react to completion before the primary's blast wave arrives and blows it apart, or it fails in a technical event called a "fizzle." Yay technology.
posted by localroger at 5:29 AM on February 2, 2010 [1 favorite]

My dad was on a Davy Crockett crew when he was in the army back in the early 60s. They obviously never practiced with nuclear warheads, only conventional explosives. His general impression was that it was a piece of shit and that he wasn't sure the range was greater than the bursting radius. I recall him saying that he would've gone AWOL if they had shipped him out with nuclear warhead.
posted by electroboy at 6:24 AM on February 2, 2010 [2 favorites]

As for the deceleration/debris non-problem in orbit: If you decelerate, you go into a lower orbit and the debris is moving faster so it goes into a higher orbit. Orbital physics ain't flatland.

Niven. Yeah. Oops.

I think the plastic shrapnel was polyethylene. Can't remember where I got that...
posted by warbaby at 8:02 AM on February 2, 2010

Fyy, there is a comic mocking paper & pencil role players called Knights of the Dinner Table where the players play a horrendous lawyeresque AD&D-like games called Hackmaster, which ultimately ended up being published as a quasi-playable game. It contained a spell called "Atomic Fireball, Nuclear Winter" that reminds me of the Davy Crockett, except the range was negligible and the blast radius was far larger.
posted by jeffburdges at 12:19 PM on February 2, 2010

localroger wrote: "nebulawindphone, the radiation doesn't actually transmit significant force."

Sure it does, although indirectly. The radiation burst will cause ablation of the pusher plate (or the graphite oil covering it), which of course causes the ship to accelerate as the atoms that were previously part of the pusher plate are removed from it. In an H-bomb, you need the styrofoam or whatever so that the compression of the fusion part of the bomb happens before it gets blown apart. It's a matter of speed, not force.

And yes, there really are far fewer long lived radioisotopes in a fission-fusion-fission device; at least that's what I remember reading back when I was of the "completely fascinated with the engineering of nuclear weapons" type.

If you detonate any nuclear device near the ground, that will obviously increase the nastiness because of the soil and buildings and things that are vaporized.
posted by wierdo at 2:21 PM on February 2, 2010

wierdo: ablation/rocket effect was step #2 of Howard Morland's progression toward learning about the foam. All nuclear shaped charges use the foam, it's the plasma that creates the directed force, and it was the H-bomb that taught us the art of building nuclear shaped charges. The reason the foam is used is that the entire mass is irradiated instantly and with beautiful symmetry, so that the forces created can be precisely controlled.

And H-bombs absolutely are even dirtier than A-bombs. They derive the majority of their energy output from the fast neutron fissioning of depleted uranium, which creates exactly the same type of waste that a self-sustaining prompt fission reaction does. When you hit a nucleus with a 5 MeV neutron and smash it to halves, it really doesn't matter much whether it's U-235 or U-238, or whether the neutron came from a fissioning U-235 or from fusion. H-bombs do not make a big bang because the H reaction liberates more energy than the U reaction; it actually generates a bit less. They make a big bang because they are able to fission large amounts of cheap U-238 instead of relatively small amounts of expensive U-235. But in the end, the vast majority of the energy comes from fission, and the waste is the same but there's more of it.

The neutrons are supplied by the fusion reaction, and it supplies a *lot* of them. If you omit the depleted uranium tamper, or replace it with something that doesn't absorb neutrons, you get what is called a neutron bomb.

Both of the claims you are making were commonly believed to be true at one time. The first was an actively encouraged bit of misdirection to obscure the true design elements; the second was never anything but pure propaganda.
posted by localroger at 3:46 PM on February 2, 2010

Got any good links, localroger? Or at least some book recommendations?
posted by wierdo at 4:34 PM on February 2, 2010

wierdo, the definitive works are Richard Rhodes' The Making of the Atomic Bomb and Dark Sun: The making of the Hydrogen Bomb. If you can find a copy I also highly recommend Robert Del Tredici's At Work in the Fields of the Bomb; last I looked many of the photos were online, but much of the value is in the notes which aren't, and take up more than half the book.

The dirtiness of H-bombs is not really controversial; if you are familiar with the acknowledged elements of the Teller-Ulam configuration and you know nuclear physics, you know it will be a dirty device. There's no way it could be otherwise.

On the issue of plasma vs. ablation it seems the debate has ebbed again since my last remembered reading. There is no doubt that plastic foam parts are considered critical components of H-bombs; Howard Morland proved this by tracing the materials, and Richard Rhodes got interviewees to admit polystyrene was integral to Mike. But Rhodes' sources told him the foam wasn't the source of the pressure. It has never seemed reasonable to me that gamma rays flashing through an empty cavity and hitting the walls at varying angles would provide a good symmetrical effect, and I seem to remember reading somewhere (might have been Dark Sun, might have been a more recent interview with Morland) that it's a combination effect where the foam absorbs the gammas and re-radiates X-rays in a better pattern, which then does the ablation.
posted by localroger at 4:49 PM on February 2, 2010

Got any good links, localroger?

google "Nuclear Weapons FAQ".
posted by c13 at 6:18 PM on February 2, 2010

warbaby, polyethelyne was indeed one of the possible sources of reaction mass for Orion.

After reading George Dyson's "Project Orion: The Atomic Spaceship 1957-1965," I don't remember ablation of the pusher plate as being a consideration in reaction mass. In fact, the graphite oil that was supposed to have been sprayed over the plate between explosions would have effectively eliminated ablation from nuclear blasts. It never ceases to amaze me that the Orion researchers found that engineered artifacts could indeed survive nuclear explosions.
posted by lhauser at 8:14 PM on February 2, 2010