# Nuke strike in space **URL:** \ **Category:** Factual Questions\ **Created:** [February 3, 2010, 3:16am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479 "2010-02-03T03:16:07Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 3, 2010, 11:53pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/21 "2010-02-03T23:53:45Z")
> [@toadspittle](#): > > I know people LOOOOOOVE the idea of rail guns, but has anyone ever made a WORKING artillery-grade rail gun? [Navy Rail Gun Test DESTROYS Everything It Touches at 5,640 mph](http://gizmodo.com/351467/navy-rail-gun-test-destroys-everything-it-touches-at-5640-mph) > [@](#): > > The Navy is researching rail guns because they would weigh less than conventional ones, and since they rely on electromagnetics to fire rounds, you wouldn’t need a big, dangerous pile of explosives stored in a magazine. All of that means a lighter ship, and a much more deadly ship: a combat-ready rail gun would be able to fire Mach 5 projectiles over 200 miles with pinpoint accuracy, hitting 5 meter targets. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 4, 2010, 12:35am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/22 "2010-02-04T00:35:14Z")
While railguns aren’t currently practical, I think that’s mostly due to atmospheric drag. Railgun projectiles have higher speed but lower mass than conventional weapons of the same energy, which means that air resistance is much more significant for them, and the energy they have is lost very quickly. Remove the atmosphere, though, and you remove the problem. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [February 4, 2010, 12:54am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/23 "2010-02-04T00:54:28Z")
Like others have said, but maybe at a higher level, is that the blast component of a nuclear detonation is a shockwave moving through the air, with essentially the effect of a VERY high almost instantaneous wind. In space there’s no atmosphere to transmit that, so unless you were so close that the actual fireball caught the ship, blast would be negligible. What would be important would be heat and radiation. The heat would all be in the form of radiative heat, and like **Billfish678** says, in all likelihood, it isn’t going to be enough to melt your battleship into a orange glob of molten steel. The thing you do have to worry about is prompt radiation. You’ll have immediate prompt radiation effects, and you’ll likely have secondary irradiation issues as a result as well. Essentially, radiation shielding will be more important- smart design would have any water storage tanks between the hull and the crew spaces. ---
**Author:** ![Umbriel2](https://avatars.discourse-cdn.com/v4/letter/u/4af34b/32.png) [@Umbriel2](https://boards.straightdope.com/u/Umbriel2)\ **Post date:** [February 4, 2010, 2:51am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/24 "2010-02-04T02:51:08Z")
> [@Squink](#): > > Wag: > You’ve got a 1000 kg warhead that’s mostly iron avg MW = 56 I think most of the mass of a nuclear warhead comes from the fissionable material itself, which would be enriched uranium or plutonium. I’m not sure how much that alters your calculation, but I’d guess it no more than doubles or triples the “1 ATM Radius”. > [@Joe Frickin Friday](#): > > Wouldn’t the penetrators (and any other solid matter within a few meters of the blast) vaporize shortly after detonation? That’s why I proposed tank round penetrators, made of tungsten or uranium, either with very high melting point. It might further be desirable to stand them off from the bomb before detonation – perhaps launched by compressed air or a small powder charge a few seconds early. And regardless of the feasibility of “shaped” nuclear charges, one could certainly cluster the penetrators to focus their dispersion however one desired. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [February 4, 2010, 3:08am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/25 "2010-02-04T03:08:11Z")
I suspect that there may be an additional effect that needs to be considered. In the atmosphere, a nuclear explosion causes a fireball, because the air becomes opaque to the radiation from the explosion. This raises the temperature of the air until it ionizes and re-radiates x-rays. In space, there isn’t going to be much of a fireball, which means that the x-rays from the explosion are going to impinge unimpeded on their target. If the target is close enough, this much energy will cause the outside of the target to ablate explosively, creating a shock wave which might be strong enough to kill anyone inside. I have no idea how close an armored spacecraft would need to be for this to be a worry. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [February 4, 2010, 3:32am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/26 "2010-02-04T03:32:38Z")
Rail gun in a nuclear bomb that detonates inside the ship. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 4, 2010, 3:56am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/27 "2010-02-04T03:56:58Z")
> [@Umbriel2](#): > > I think most of the mass of a nuclear warhead comes from the fissionable material itself, which would be enriched uranium or plutonium. I’m not sure how much that alters your calculation, but I’d guess it no more than doubles or triples the “1 ATM Radius”. Nah, uranium or plutonium being heavier elements (fewer total moles) would _decrease_ the gas volume relative to iron for a given bomb mass. That’s a big part of why I said my number was an _over_estimate. Naturally under fireball conditions, you’ll also see some pretty big deviations from the ideal gas law, so my estimate is very much only an estimate. That aside, you could increase the size of the blast envelope by shrouding your bomb in a container of low a molecular weight gas like helium, but that approach would quickly become unwieldly. No one wants an atom bomb that’s 40 feet in diameter, even if you could use it to wreck spaceships at a distance of 2 km. ---
**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\ **Post date:** [February 4, 2010, 1:52pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/28 "2010-02-04T13:52:56Z")
[This site](http://www.projectrho.com/rocket/rocket3x1.html) has a lot of discussion on this topic. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 4, 2010, 6:35pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/29 "2010-02-04T18:35:46Z")
What does it matter if our penetrators get vaporized? They’ve still got just as much mass, and just as much speed. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 4, 2010, 6:48pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/30 "2010-02-04T18:48:49Z")
> [@mlees](#): > > Well, I was going to mention the atmosphere… > > But even with the atmosphere to transmit shock, an airburst did not sink the Nevada. > > It did sink other, less armored, targets. Even this is mitigated on the specific facing/aspect the target was in relation to the blast. > > The underwater blast (test “Baker”) did a whole lot more dramatic damage, because water does not compress as much as air does, so it transmits more “shock”. It caved in the whole starboard side of the USS Arkansas. During the discussion about reactivating the _Iowa_-class battleships during the Reagan era, it was mentioned that they (better-protected than the _Nevada_ and _Arkansas_, albeit not orders of magnitude better) were regarded as the man-made structures most likely to survive a nuclear near-miss. (Presumably nothing survives a direct hit). ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [February 4, 2010, 7:01pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/31 "2010-02-04T19:01:45Z")
I think you guys need to go look up some Orion Spacecraft data for a decent answer. I doubt the thing was gonna fly with 10 foot thick steel plating with nukes being detonated a mile or two away. Of course how much closer and thinner than that is what everyone is interested in. ---
**Author:** ![Umbriel2](https://avatars.discourse-cdn.com/v4/letter/u/4af34b/32.png) [@Umbriel2](https://boards.straightdope.com/u/Umbriel2)\ **Post date:** [February 5, 2010, 5:23am UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/32 "2010-02-05T05:23:01Z")
> [@Chronos](#): > > What does it matter if our penetrators get vaporized? They’ve still got just as much mass, and just as much speed. Molten, you’re quite right. Vaporized, I think they’d disperse too rapidly to give a useful range benefit. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [February 5, 2010, 4:29pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/33 "2010-02-05T16:29:20Z")
> [@billfish678](#): > > I think you guys need to go look up some Orion Spacecraft data for a decent answer. I doubt the thing was gonna fly with 10 foot thick steel plating with nukes being detonated a mile or two away. > > Of course how much closer and thinner than that is what everyone is interested in. In the case of nuclear-pulse propulsion you’re not using a raw nuke; you’re using one clad in material designed to absorb and focus the blast to convert as much of the bomb’s yield as possible into kinetic energy. The pusher plate would be hit by a fast-moving plasma that would be “only” 67,000 K- ultraviolet hot, not x-ray hot. I couldn’t find a reference to plate thickness but Wiki says the bombs were to be detonated 30 meters behind the pusher plate. > [@Chronos](#): > > While railguns aren’t currently practical, I think that’s mostly due to atmospheric drag Currently the main problem is that the railgun blasts itself into shreds in the course of accelerating the projectile. Until that’s solved we’re still in the “proof of concept” stage. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [February 5, 2010, 5:36pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/34 "2010-02-05T17:36:25Z")
> [@Lumpy](#): > > Currently the main problem is that the railgun blasts itself into shreds in the course of accelerating the projectile. Until that’s solved we’re still in the “proof of concept” stage. That’s what I, too, thought the issue was. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 5, 2010, 5:53pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/35 "2010-02-05T17:53:12Z")
> [@Lumpy](#): > > Currently the main problem is that the railgun blasts itself into shreds in the course of accelerating the projectile. Until that’s solved we’re still in the “proof of concept” stage. And overheats due to induction heating in the railgun structure and magnets from eddy currents, which of course would be an even larger problem in space (where the only heat transfer is via radiation) than in atmosphere. As others have mentioned, a raw nuclear core is just going to deliver most of its energy in the form of high frequency electromagnetic radiation (x-rays, gamma rays) and and neutrons, the proportions of which depend on the material and rate of reaction. These will naturally propagate outward in a spherical fashion dropping off in intensity by a square of distance. However, it is possible to both focus the radiation using a shaped cavity made of material that reflects x-rays or neutrons, or convert the energy into a directed kinetic pulse by introducing material to absorb the radiation and be vaporized, or both. In fact, this is exactly how the fission Primary in a thermonuclear weapon works; the detonation energy is confined, converted, and directed to compress the thermofusion Secondary until it achieves a fusion state. Most boosted fission weapons work on a somewhat similar principle, although they don’t have a separate Secondary; rather the detonation is confined enough to achieve limited fusion, which then pumps out more neutrons that are fed back into the pit to enhance the rate of fission before the pit blows itself apart. You can also use a fission weapon that is optimized to produce x-rays to power an x-ray frequency laser, or as a neutron source for a particle beam (albeit with only a single shot as the weapon consumes itself and at low overall efficiency). However, if you are in orbital space, it’s probably far easier to simple launch a bunch of shrapnel in an intercepting orbit and let Isaac Newton do his thing. The amount of kinetic energy in orbit is utterly beyond terrestrial comprehension; a 1 kg projectile at crossing Low Earth Orbit (i.e. essentially hitting a stationary target) will have nearly 43 million foot-lbf of energy (58.3 MJ). That is more than a modern discarding sabot tank round, and there is no way you could build any functional spacecraft to withstand this kind of impact. Really all you need to do is release a few hundred such projectiles in an intercept track and wait to swing back around next orbit to sweep up the wreckage. Stranger ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [February 5, 2010, 9:51pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/36 "2010-02-05T21:51:16Z")
> [@Lumpy](#): > > In the case of nuclear-pulse propulsion you’re not using a raw nuke; you’re using one clad in material designed to absorb and focus the blast to convert as much of the bomb’s yield as possible into kinetic energy. The pusher plate would be hit by a fast-moving plasma that would be “only” 67,000 K- ultraviolet hot, not x-ray hot. I couldn’t find a reference to plate thickness but Wiki says the bombs were to be detonated 30 meters behind the pusher plate. > > . A bunch of 67k hot stuff is about the same as a tiny bit of x-ray hot stuff when it comes to the thermal load hitting the plate/ship. Lets assume an Orion nuke had 1000 lbs of clading material in addition to the nuke itself. Our weapon nuke does not. A rough estimate would be that our space wessel would have 1000 lbs of steel ablated off of its surface. That would be a pretty thin layer in comparision to a thick steel hull on some kind of large space destroyer. That 30 meter number confirms my initial WAG of hundreds of feet. 30 meters is about a hundred feet. Double or triple that so its 200 to 300 feet and the blast effects will go down by a factor of 4 to 9. And given that Orion could take hundreds of these blasts, a remotely stout space destroyer should be able to take one or two (or at the very least wouldn’t be blown to shit in some dramatic hollywood fashion because OMG! it was a NUKE!). ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [February 5, 2010, 10:01pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/37 "2010-02-05T22:01:17Z")
> [@davekhps](#): > > If you have a battlestar, they can take nuke hits all the time and keep on moving :). Were those actual hits or proximity bursts? Surely you wouldn’t want the nuke to actually hit in case it was damaged and failed to detonate. Detonating a meter or three above the surface of the target however… ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [February 5, 2010, 11:05pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/38 "2010-02-05T23:05:20Z")
> [@billfish678](#): > > A bunch of 67k hot stuff is about the same as a tiny bit of x-ray hot stuff when it comes to the thermal load hitting the plate/ship. > > Lets assume an Orion nuke had 1000 lbs of clading material in addition to the nuke itself. Our weapon nuke does not. A rough estimate would be that our space wessel would have 1000 lbs of steel ablated off of its surface. That would be a pretty thin layer in comparision to a thick steel hull on some kind of large space destroyer. > > That 30 meter number confirms my initial WAG of hundreds of feet. 30 meters is about a hundred feet. Double or triple that so its 200 to 300 feet and the blast effects will go down by a factor of 4 to 9. And given that Orion could take hundreds of these blasts, a remotely stout space destroyer should be able to take one or two (or at the very least wouldn’t be blown to shit in some dramatic hollywood fashion because OMG! it was a NUKE!). The main difference in how hot the plasma is is that you do NOT get penetrating x-rays heating the target several centimeters deep. In the case of the Orion, heating is minimal because the kinetic impulse is transmitted very quickly, on the order of milliseconds. The physicists working on Orion figured that if you simply sprayed a light coat of oil on the pusher plate between pulses, the coating would ablate enough to completely protect the plate itself. But as you say, a warhead is rather different from the clad nukes Orion would use. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [February 5, 2010, 11:30pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/39 "2010-02-05T23:30:08Z")
> [@Lumpy](#): > > The main difference in how hot the plasma is is that you do NOT get penetrating x-rays heating the target several centimeters deep. In the case of the Orion, heating is minimal because the kinetic impulse is transmitted very quickly, on the order of milliseconds. The physicists working on Orion figured that if you simply sprayed a light coat of oil on the pusher plate between pulses, the coating would ablate enough to completely protect the plate itself. But as you say, a warhead is rather different from the clad nukes Orion would use. I know all that. Read that stuff before. Now do a calc and tell me how hot those several centimeters would get. My WAG is that I don’t think they would get particulary hot from just one blast. For a rough measure, consider ground zero for the very first bomb test (on the order of strength the OP was asking about). Some sand there was turned to glass, but I am pretty sure it wasnt particularly thick. And there is the possibilty the effect would have been even LESS if the atmosphere wasnt there. And how high was that tower anyway? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 5, 2010, 11:54pm UTC](https://boards.straightdope.com/t/nuke-strike-in-space/527479/40 "2010-02-05T23:54:59Z")
> [@billfish678](#): > > Some sand there was turned to glass, but I am pretty sure it wasnt particularly thick. [Trinitite](http://en.wikipedia.org/wiki/Trinitite): > [@](#): > > The glass has been described as "a layer 1 to 2 centimeters thick, with the upper surface marked by a very thin sprinkling of dust which fell upon it while it was still molten. However: > [@](#): > > In 2005 it was theorized by Los Alamos National Laboratory scientist Robert Hermes and independent investigator William Strickfaden that much of the mineral was formed not simply by sand which was exposed to the fireball, but the sand which was drawn up inside the fireball itself and then rained down in a liquid form. If that’s the case, then the flash formed layer would be thinner than 1 to 2 cm. But that’s in sand, not hull metal. The two materials are quite a bit [different](http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html) thermally. [Previous page](https://boards.straightdope.com/t/nuke-strike-in-space/527479.md?page=1) [Next page](https://boards.straightdope.com/t/nuke-strike-in-space/527479.md?page=3)