Straight Dope Message Board

[SenorBeef]

When a nuclear missile sub receives a fire order, it will receive a fire plan alongside it. There are thousands of pre-programmed fire plans that can be referenced in code as part of the fire order to tell the sub where it's going to hit.

Could the sub's captain instead choose his own targets arbitrarily, or will the targeting computers only fire on the coded target plan? Or somewhere in between - the captain can't pick targets arbitrarily, but he can choose from among pre-programmed fire plans.

There's probably no great importance to this as a passive safety measure - my understanding is that the sub cannot fire without the fire codes issued through the fire order, so the captain couldn't go crazy and launch nukes one day. I guess I'm curious, since submarines are intended as a second strike weapon, if the captain could change targets in the absense of command following a successful nuclear strike on the nuclear communication network. Perhaps hold on to a few missiles in reserve to target them as he chooses as the situation develops.

[joema]

Originally Posted by SenorBeef

...the sub cannot fire without the fire codes issued through the fire order, so the captain couldn't go crazy and launch nukes one day...

Supposedly (at least during the Cold War) a US SSBN could independently launch missiles without an authenticated action order and without receiving PALs (Permissive Action Links). This was due to the difficulty of communicating with submerged submarines.

However it wasn't solely up to the captain. Numerous keys were involved and it would physically require the cooperation of much of the crew. It's a lot more complex than pressing a button.

During the earliest phase of the Cold War when nuclear-armed submarines were used, launch was apparently an "all or nothing" affair. Former nuclear weapons planner Daniel Ellsberg revealed this in his recent book "The Doomsday Machine".

Whether during that era and the end of the Cold War, multiple targeting options were available to SSBN captains, I don't know. The overall goal was to prosecute the SIOP (Single Integrated Operational Plan): https://en.wikipedia.org/wiki/Single...erational_Plan

Since 2003 that was replaced by Operations Plan (OPLAN) 8044; not sure if any non-classified info exists about that.

According to this 2001 Time Magazine article, an authenticated emergency action message was required (at that time). I'm not sure if that covered contingency situations where no communications were available. http://content.time.com/time/magazin...1361-1,00.html

Due to the complexity of surveying targets and programming the missile guidance systems, it would seem very likely that only certain pre-programmed targets could be used. Whether the geographic details of those are visible to the SSBN captain (or just opaque plans), I don't know.

[AK84]

Exact capabilities of nuclear missiles, especially their targeting and retargeting abilities are some of the most classified information for nations which have them.
As are the comm abilities for units.

[Chronos]

I'm sure that you couldn't completely pre-program the missile navigation, because that would depend on not only the target's position, but the sub's. Part of the point of a missile sub is that it's mobile and can launch from an arbitrary location.

That said, it wouldn't be a very difficult calculation. Probably the hardest part would be getting a precise fix for the sub's own location. And unless the sub's own navigation systems were completely automated and directly tied in to the launch computers, an independent-minded captain could launch on an arbitrary target by finding some approved target at the same latitude and spoofing the sub's longitude.

[SamuelA]

What I always wondered was if you needed to fire on U.S. soil, if anything prevents the ICBM operators from selecting a target in that region. For example, in various science fiction scenarios, the aliens are invading through portals (and thus are concentrated in one place and defeatable) and need to be nuked. So the President orders the strike, but the question is how straightforward it is to fire a nuke on LA or whatever.

[MichaelEmouse]

Most weapon systems have a manual targeting mode, if only as a backup. I understand that people who work in both the military and the nuclear field really like having backups.

Wouldn't you want to be able to aim nukes at locations you didn't expect? Many of your potential targets might move. If your intel is telling you that Russian ballistic missile-launching trucks have assembled in some field near the Finnish border and are going through their launching preparations, wouldn't you want the option to fire at any arbitrary point and not just at locations you thought you might need when you programmed it?

[DPRK]

Originally Posted by SamuelA

What I always wondered was if you needed to fire on U.S. soil, if anything prevents the ICBM operators from selecting a target in that region. For example, in various science fiction scenarios, the aliens are invading through portals (and thus are concentrated in one place and defeatable) and need to be nuked. So the President orders the strike, but the question is how straightforward it is to fire a nuke on LA or whatever.

Well you don't necessarily need to waste an inter-continental ballistic missile to take out your own positions...

An authorized (say by the Global Strike Command) re-targeting can obviously be performed pretty quick, but the regular missile crew cannot upload arbitrary code to the guidance computer on their own initiative. The real question was about submarine-based missiles; to the extent they are known to have PALs, it stands to reason things like re-targeting coordinates need to be authorized no less than with land-based missiles. An interesting question is the situation with systems like British naval SLBMs which are not equipped with permissive action links; the crew can launch on their own, but can they add new targets as well?

[Tim@T-Bonham.net]

Originally Posted by SenorBeef

I guess I'm curious, since submarines are intended as a second strike weapon, if the captain could change targets in the absense of command following a successful nuclear strike on the nuclear communication network. Perhaps hold on to a few missiles in reserve to target them as he chooses as the situation develops.

I believe such 'holding back a few' was discouraged, because once your sub fired off any missiles, you were now exposed as a target and could expect an enemy missile incoming soon. Better to get all your missiles heading for the enemy before that happened.

As a sub, you could move, but only so fast, so your general vicinity would be known. And the advances in satellites, radar, & electronics since then would make it even harder to remain hidden.

[SamuelA]

Originally Posted by Tim@T-Bonham.net

I believe such 'holding back a few' was discouraged, because once your sub fired off any missiles, you were now exposed as a target and could expect an enemy missile incoming soon. Better to get all your missiles heading for the enemy before that happened.

As a sub, you could move, but only so fast, so your general vicinity would be known. And the advances in satellites, radar, & electronics since then would make it even harder to remain hidden.

I wonder what the submarine kill or mission kill radius is for a 1-megaton warhead - or a barrage of 10 or so MIRV warheads - set to detonate at the ocean surface.

[HurricaneDitka]

Originally Posted by SamuelA

I wonder what the submarine kill or mission kill radius is for a 1-megaton warhead - or a barrage of 10 or so MIRV warheads - set to detonate at the ocean surface.

I'm sure it depends on the depth of the submarine and probably some of the ocean conditions, but I wouldn't expect it's all that good. Most of the force of the blast is going to go back up into the atmosphere isn't it?

ETA: wikipedia says "modern vessels typically launch while submerged at keel depths of usually less than 50 metres (160 ft).". That seems like a good bit of ocean between the sub and the nuclear blast, and they've got all the time it takes an adversary to launch and the missile flight time to put even more ocean between them and the blast.

[Baron Greenback]

Originally Posted by Tim@T-Bonham.net

As a sub, you could move, but only so fast, so your general vicinity would be known. And the advances in satellites, radar, & electronics since then would make it even harder to remain hidden.

Fire a volley, and then dive hard? How deep would you have to go so that a retaliatory surface strike a) doesn't inflict any damage, b) conveniently screws up the attempted tracking?

[Chronos]

If you want to "hold a few back", then you'd hold back a few entire submarines. That way, the reserves continue to be hidden.

[rbroome]

I have no knowledge of nuclear weapons targeting, but I am aware of concerns back in the cold-war days of the USSR "sterilizing" large parts of the N. Atlantic of US submarines. Apparently it took dozens to hundreds of warheads but given that at the time the USSR had >10,000 warheads, planners were concerned. If you could get the warheads to penetrate the water surface, I have no idea how hard that would be but I suspect it wouldn't be easy, the blast effect to damage a submarine was measured in cubic kilometers.
All these discussions that I heard about were theoretical and a long time ago.

[Sicks Ate]

A good read for those interested in things nuclear:

https://www.goodreads.com/book/show/...nd-and-control

Apologies for the clumsy format, on my phone.

[HurricaneDitka]

That sounds like a pretty crazy plan: just blanketing the ocean with nuclear explosions every few kilometers. You'd probably sink a whole bunch of neutral vessels, and maybe some of your own ships too. You'd probably kill most of the marine life too, but I suppose if you're thinking it's a nuclear holocaust, those concerns are pretty far down the list anyways.

Wikipedia says an Ohio SSBN has a test depth of 800 feet and a top speed of 20 (official) - 25 (reported) knots

[SamuelA]

Originally Posted by rbroome

I have no knowledge of nuclear weapons targeting, but I am aware of concerns back in the cold-war days of the USSR "sterilizing" large parts of the N. Atlantic of US submarines. Apparently it took dozens to hundreds of warheads but given that at the time the USSR had >10,000 warheads, planners were concerned. If you could get the warheads to penetrate the water surface, I have no idea how hard that would be but I suspect it wouldn't be easy, the blast effect to damage a submarine was measured in cubic kilometers.

Well, if you had the MIRV warheads reenter at a shallow angle and put at least a small parachute or inflating decelerator on them, they could hit the water at a speed low enough not to break the warhead. Then you could have them descend a couple of kilometers and set the warhead off there. That would presumably have the maximum probability of killing a submarine. If you then had at least a vague idea where the enemies ballistic missile submarines were, you could destroy them. Much like the boardgame "battleship"

[KarlGauss]

Incoming missiles and nuclear blasts against US (and likely Russian) subs would have to penetrate more than water, no?

If the sub launches from a hole in the ice-cap, and stays close to the edge, they may duck back underneath it. Would ice be a better, worse, or highly similar nuclear explosion deflector/absorber than the ocean?

ETA: I assuming a 'thick' cap of ice.

[GMANCANADA]

I can't comment on subs, but a few years ago we did a tour of the Titan Missile Museum in Arizona.

http://www.titanmissilemuseum.org/home

Absolutely amazing place, worth a trip out of your way if you're ever in area.

I appreciate that sometimes tour guides don't let the truth get in the way of a good story, but our tour guide was retired former military staffer from when it was operational, he said (for the land based missiles) that the operators had absolutely no idea where the missies were targeted. Each missile was pre-programmed with multiple targets and the specific target was determined by the authorization code they received (via a phone call) and then manually entered. The targets were considered highly classified then and have still never been released. As he noted, potential targets may be "secret" Russian bases that the Pentagon still doesn't want Russia to know they're aware of.

They would either be ground strikes or air bursts. Ground strikes were meant to maximize casualties and destruction at a military target, like a base or other missile site. Air strikes would burst above a target, knocking out communications with minimal casualties, presumably over a civilian target like Moscow.

He said the govt did not tell them the specific target(s) because they knew the personnel were people with families etc "and did not want them second guessing and either deciding to abort because they didn't want to risk killing civilians etc or feeling remorse afterward for what they did".

I asked him what he would have done if he had been one of the group to get the launch order. He was honest and said he really didn't know, when he thought about actually launching, in his mind it was an air burst over a low populated civilian target. He had trouble with the idea of killing 100,000 people with a button push. He said one colleague was clear that he would never launch and others were adamant they would follow orders.

Finally - Back to the OP - I don't see why the same logic of keeping the specific targets classified wouldn't hold for the subs. It doesn't make sense make sense for a sub to retarget its missiles if they don't know where they were targeted to begin with. Why would they tell the sub crew, but not be willing to tell the ground crew?

[MEBuckner]

Originally Posted by GMANCANADA

Air strikes would burst above a target, knocking out communications with minimal casualties, presumably over a civilian target like Moscow.

Nuclear air bursts by no means cause "minimal casualties"; my understanding is that an air burst over a "soft target" (like an airfield or a city or a column of enemy troops) maximizes the destruction (spreads it out over a wider area)--both Hiroshima and Nagasaki were air bursts. Air bursts also don't create giant craters in the ground. And a ground burst doesn't "maximize casualties" as such, but seeks to destroy a "hardened" target like a deeply-buried bunker or an ICBM silo. Ground bursts may in fact cause relatively minimal immediate casualties, if all you're doing is blowing a giant hole in the ground in Wyoming or North Dakota or someplace like that (although that farmer whose house is next to the missile silo is presumably toast), but they're also very "dirty" in that they create a lot of radioactive fallout because so much material from where the crater is has been drawn up into the fireball, irradiated, and spewed back out over the landscape, potentially hundreds of miles downwind.

Finally, there is the possibility of a very high-altitude EMP strike, which could potentially knock out communications and other electrical and electronic systems over much of a continent. (The "air bursts" are relatively low altitude, as in hundreds or thousands of feet off the ground.)

[GMANCANADA]

My mistake - I believe he was talking about the a "very high altitude" option as the second option. He said the purpose was to create an EMP which would damage the communications capabilities with minimum casualties.

[AK84]

Originally Posted by MichaelEmouse

Wouldn't you want to be able to aim nukes at locations you didn't expect? Many of your potential targets might move. If your intel is telling you that Russian ballistic missile-launching trucks have assembled in some field near the Finnish border and are going through their launching preparations, wouldn't you want the option to fire at any arbitrary point and not just at locations you thought you might need when you programmed it?

If thats the information you get, then say your prayers, you are already dead. Its like getting information that a guy is pressing the trigger on a handgun, whose muzzle is contated with your temple; 0.025s before the action cycles.

Mobile launchers can fire within a minute from pre-surveyed sites.

[MEBuckner]

Originally Posted by SamuelA

What I always wondered was if you needed to fire on U.S. soil, if anything prevents the ICBM operators from selecting a target in that region. For example, in various science fiction scenarios, the aliens are invading through portals (and thus are concentrated in one place and defeatable) and need to be nuked. So the President orders the strike, but the question is how straightforward it is to fire a nuke on LA or whatever.

Originally Posted by MichaelEmouse

Wouldn't you want to be able to aim nukes at locations you didn't expect? Many of your potential targets might move. If your intel is telling you that Russian ballistic missile-launching trucks have assembled in some field near the Finnish border and are going through their launching preparations, wouldn't you want the option to fire at any arbitrary point and not just at locations you thought you might need when you programmed it?

For the U.S. at least we still have the concept of the "nuclear triad", including manned bombers which can launch not only nuclear-armed cruise missiles but also drop nuclear bombs. Those would presumably be the weapons that would be used in any kind of "Godzilla is attacking Los Angeles"/"Martians have landed in Iowa" sort of scenario, rather than trying to re-target our own SLBMs or ICBMs to hit American soil.

Of course, even supersonic airplanes are vastly slower than long-range ballistic missiles; so as AK84 points out, trying to preemptively take out a mobile missile launcher that way (or any other way, most likely) is fundamentally unworkable. Bottom-line, both superpowers spent a lot of time and money and effort making damn sure that the Other Side could not somehow "shoot the gun out of their hand" and then simply dictate terms, thus "winning" a nuclear war (and maybe "only" killing a few tens of millions of people and conceivably still leaving an enemy country worth conquering).

[AK84]

Already the return of great power competition is making people wonder if the reduced Arsenals are an invitation to strike first.

[Francis Vaughan]

Part of the problem in retargeting missiles in the subs is that they form part of the strategic weapons component of the nuclear defence. Their job is not to strike enemy forces engaged in belligerent or threatening action. Their job is to retaliate and render an attacking enemy's country incapable of defending itself against even a band of kids armed with pointed sticks. The targets for this are determined a long time ahead, and don't change. Even if you got into a conflict that was starting to escalate badly, the nuclear subs would not be called into play. The subs are there for ultimate retaliatory action, not first strike, or tactical strikes. As such there isn't a requirement that the missiles be retargetable. Prudence would suggest that targeting would be managed in much the same manner as for land based ICBMs. A launch order code that selects from a set of targets, none of which are known, or knowable, to the sub's crew.

[txjim]

An interesting (to me) aspect of nuclear command and control is the E-6B Mercury aircraft which relays the commands to sea and land assets

[SamuelA]

Originally Posted by txjim

An interesting (to me) aspect of nuclear command and control is the E-6B Mercury aircraft which relays the commands to sea and land assets

In some ways, the interior of the aircraft is informative. People who believe the government has secret technology years or decades ahead of the civilian world - and sure, in limited domains it does - would wonder why they are holding back the good stuff for the aircraft to be used in Armageddon. Where's the antigravity or holographic displays? Or even capacitive touch screens or VR?

[Chronos]

Francis Vaughn, that's exactly why they must be retargetable. You don't know what the remaining important targets are going to be, after all else is said and done. Maybe a few of the initial ICMB targets survived. Maybe the most effective strike to reduce the enemy's capability will be against mobile assets. Heck, maybe World War III was against a completely different country than you anticipated.