Beating swords into really long sharp knives.

April 20, 2006 10:45 PM

With the end of the Cold War, the U.S. Navy realized it didn't need MAD numbers of Ohio class nuclear submarines loaded with multiple nuclear warhead Trident missiles. Although it has taken the Navy nearly 20 years to figure out something else to do with the excess boats, they've got it now. Welcome the USS Ohio (once SSBN 726, now SSGN 726) and the USS Florida (once SSBN 728, now SSGN 728) and their 308 (154 each) Tomahawk cruise missiles back to service. Or, not. [more inside]
posted by paulsc (22 comments total)

Trade in 24 Trident ballistic missiles (each of which could have been equipped with 4 Multiple Independent Re-entry Vehicle [MIRV] nuclear warheads, for a total load of 96 warheads per ship) for 154 Tomahawk cruise missiles, each of which can be equipped with the 200 kt. W-80 tactical nuclear warhead, all wrapped up in a very well proven stealthy delivery platform you can drive right up to an evil enemy's coast, and you've got one heck of first strike tactical front line for conducting gunboat diplomacy against hardened targets. But according to a footnote in this report to Congress [warning: link to PDF file], under the unique logic of the Bush administration towards nuclear arms control treaties, we've actually accomplished arms reduction in doing this!

"Under the previous START strategic nuclear arms reduction treaties, the SSGNs would remain accountable as strategic nuclear launch systems because they would retain their large-diameter SLBM launch tubes. Four SSGNs, even though they carried no SLBMs, would be counted as carrying 96 Trident SLBMs each with 4 nuclear warheads, for a total of 384 warheads. Having to include 384 “phantom” warheads within the allowed START II U.S. strategic nuclear force of 3,500 warheads was viewed as problematic from a U.S. perspective, since it would deprive the United States of about 11% of its permitted warheads. The alternative of asking Russia to exempt SSGNs from the counting scheme was also viewed as problematic, since Russia would likely either refuse or ask for something significant in return. The phantom warhead issue would
have been even more pronounced under a potential START III treaty that might have limited the United States to 2,500 or fewer nuclear warheads. The phantom warhead issue appeared to have receded for a time due to the Administration’s originally stated intention to not complete ratification of START II, and to instead reduce U.S. strategic nuclear forces unilaterally, without the use of new treaties. This would leave only the older START I treaty, with its much higher permitted nuclear force levels, as an in-force treaty against which the SSGNs could be counted. On February 5, 2002, however, Secretary of State Colin Powell announced that the United States was seeking a legally binding agreement with Russia on future levels of strategic nuclear weapons. This created a potential for the phantom warhead issue to once again become potentially relevant. The new U.S.-Russian arms treaty announced on May 13, 2002, resolves the issue from the U.S. perspective by counting only operationally deployed strategic nuclear
warheads and not strategic nuclear launch systems. Since the SSGNs will not deploy strategic nuclear warheads, the Administration is excluding them from the treaty’s limit of 1,700 to 2,200 operationally deployed warheads. Russia to date has not publicly objected to this interpretation."

posted by paulsc at 10:54 PM on April 20, 2006

"That which we call a nuke / By any other word would smell as sweet."
posted by bardic at 10:57 PM on April 20, 2006

"Ships and water - that is all we ever talked about in the Navy"
posted by Samuel Farrow at 11:00 PM on April 20, 2006

I mean it gets weirder and weirder and weirder. What more can I say?
posted by donfactor at 11:23 PM on April 20, 2006

Okay I have no idea what this is supposed to mean.
posted by delmoi at 11:36 PM on April 20, 2006

I know people who built Trident II missiles. We're probably better off without them. (the missiles, not the people)
posted by mr_crash_davis at 11:46 PM on April 20, 2006

the title of this post is one of the best post titles I can remember ever having read. amazing.
posted by shmegegge at 12:10 AM on April 21, 2006

the title of this post is one of the best post titles I can remember ever having read. amazing.

Agree.
posted by pkingdesign at 12:32 AM on April 21, 2006

Is this something that I would have to have a nuclear arsenal to understand?

sorry
posted by antifuse at 1:47 AM on April 21, 2006

The title is, indeed, great. :)
posted by Malor at 4:06 AM on April 21, 2006

Keep it up, guys. You'll have world peace in no time, at this rate. Just keep loading yourselves up with more armaments.

Yep. The world will be really, really peaceful and very quiet and still.
posted by Drexen at 5:19 AM on April 21, 2006

We can make a desert and call it peace!
posted by Justinian at 5:46 AM on April 21, 2006

Note that the Trident D5 can carry more warheads that the current treaty regulations allow -- at least 8 admitted, and there are rumors that it may be as high as 14.

24x8 is 192 warheads. Fitting 154 BGM-109 TLAM-N gets you 154 warheads. By the not-ratified START II treaty, this is bad, because of the limit of 5 warheads per D5 (and we only carry four currently) but in real terms, the SSGN-726 carries fewer warheads, and *far* less destructive power, than the SSBN-726 did.

The W80 on the TLAM-N is a dial-a-nuke, from 5kt to 150kt. The W88 on the D5 yields 450kt. So, at full load, the SSBN-726 held 24*8*.45=86.4Mt, while the SSGN-726 holds 154*1*.15=23.10Mt (and possibly less, depending on the yield selection.)

Now, range. The Tomahawk nuclear variants have about a 2000km range -- they were made to be bomber delivered. The D5 is basically global ranged -- it can't quite hit the antipode, but it is trivial to put a D5 carrying submarine into a position where it can hit any landmass it chose to. So, if you run a SSGN up to a coast, it can wreck hell withing about 750 miles, but that's about it. A D5 can sit a couple of thousand miles away, and hit every city in a large country.

There's also the factor that the Navy currently doesn't have any Nuclear Tomahawk variants -- they were retired long ago (as was the Air Force nuclear Tomahawks, replaced by the AGM-129.) This isn't that big a factor, though -- we know how to build them, we have the warheads in stock, making new ones wouldn't be that hard.

Currently, nuclear weapon limitation treaties concentrate on the launchers, not the warheads, because the launchers tend to be big and easily seen, while the warheads aren't. Thus, you can cut up a submarine or bomber, or blow up a missle silo, and leave the bits lying on the ground for a month or two to allow the other treaty partners a chance to fly spysats over and verify you did destroy the launcher. So, the SSGN, with 24 launch tubes, count as launchers, since there isn't an easy way to ensure that they can't easily be brough back into service as SSBNs.

I'm not worried about the implications of the Ohio SSGNs as nuclear weapons platforms, given that with the current administration's attitude towards treaties, the fact that an unratified piece of paper say limit the warheads on the D5 is meaningless. The SSGN Ohios may in fact someday (lord, I hope not) fire 154 150kt nuclear weapons -- but the SSBN Ohios will be firing more warheads, with larger yields, further away. And, of course, we'd all be fucked anyway.

My problem with the SSGN conversion is simple -- is it worth the cost? Is $1 billion worth the ability to sneak 154 cruise missles and 60 US Navy Seals up to a coast useful enough?

We already have SO submarine, including of the Navy's newest and best subs, the Jimmy Carter SSN-23. The Carter certainly cannot carry 154 Tomahawks, but can carry some, and certainly can carriy SOF forces. Furthermore, unlike the Ohio hulls, built to "dig a hole in the ocean, hide in it, and pull the water in behind them.", the Carter is built with the sort of gear that makes it possible to work up close to coasts. She's also probably faster than the Ohio's, but nobody's talking -- offically, she's as fast as every other US Submarine -- "Faster than 20kts, diving deeper than 400 feet."

If we had big navy fleet-on-fleet combat, the SSGN could be a big factor, as she pops up and throws 154 missles at the bad guys. That's not likely to happen anytime soon, and I seriously doubt they'll ever carry the anti-ship version of the Tomahawk (which has a much larger warhead, but a much shorter range.)
posted by eriko at 5:47 AM on April 21, 2006

This actually makes much more sense then the post implies. START and other nuclear treaties were designed to limit strategic nuclear weapons -- long range, city-destroying missles and their delivery systems. The Ohio-class was originally designed to deploy these weapons. The point of the conversion was not to create the ability to deliver more nuclear missles, but rather to make it a platform for special forces and cruise missles, in other words, to turn it into a tactical weapon, since the US is no longer planning a large-scale nuclear deterrent. Yes, it could also launch weapons equiped with tactical warheads, but so can nearly every other ship or plane in the US military, that is not the primary purpose of the cruise missles.

Leaving aside whether the conversion was a good idea, the problem was that, under START, the Ohio-class was still considered a strategic delivery platform, because they still had large missle launch tubes. Since START limited the number of launchers as well as the number of weapons themselvs, under this interpretation, the Ohio class submarines would still count as a large portion of the US arsenal even though they could no longer carry strategic nuclear weapons. However, this is no longer an issue, as the article says,since Russia seems to agree with the US's interpretation that the modified Ohios shouldn't count.

So, the arms control issue is a bit of a red herring. Whether or not this was a smart idea or a waste of cash by the navy remains an issue, though.
posted by blahblahblah at 5:56 AM on April 21, 2006

Or, what eriko said, just not as smartishly.
posted by blahblahblah at 5:58 AM on April 21, 2006

Neat post. The 'money shot'

$11,210,000,000 - total program cost (TY$) - since '83.

That wouldn't get you 2 months in iraq! Plus you can paint these missiles with those neat orange nose decals. Soooo pretty.

I wonder how this figure's calculated.

--

Eriko:Question: How do dial-a-nukes work? Is ist an inhibitory mechanism (slow down chain reaction) or do they add another source of fast neutrons?
posted by lalochezia at 7:15 AM on April 21, 2006

lalochezia: you see, the tomahawk missile knows where it is, by subtracting where it isn't... It's a smart missile.

Oh, and yeah... i am jealous of this post's title. Good on ya paulsc
posted by indiebass at 7:35 AM on April 21, 2006

Tangentially, these guys look at the possibility that the US has knowingly developed a first strike capacity against Russia or China. One bit of evidence is that the Navy is updating many of its submarine based strategic warheads (W-76s) to allow for ground-burst detonation. This only makes sense (they claim) if you are thinking about attacking many large hardened targets, more like fields of missile silos than a few underground bunkers in a rouge state.
posted by thrako at 8:27 AM on April 21, 2006

Spot on title. Here I was thinking they were going to be converted houseboats or something.
posted by dreamsign at 8:28 AM on April 21, 2006

How do dial-a-nukes work? Is ist an inhibitory mechanism (slow down chain reaction) or do they add another source of fast neutrons?

That's probably really classified, but some guesses can be made. It's assumed that the stages are initial fission only, the lowest, then boosted fission, then boosted fission allowing the secondary to fuse, and then the full fission-fusion-fission cycle, where the fast neutron flux from the fusion cycle either fissions the tamper (this is what caused the serious overyield of Castle Bravo -- they though 5MT, they got almost 15MT).

The most likely mechanism is boosting -- from no boost to full boost, usually via a neutron source, possibly with tritium thrown in for the highest yields (technically, this is now a fusion weapon, but the main reason is more fast neutrons, not actual yeild.) The very lowest yields are probably incomplete prompt critical explosion -- what they called fizzles in the early test days.

Selectable yields with full fusion secondaries are harder -- these probably require some manual reassembly of the warhead, so this would be more depot-level work than tactical selection of yield.
posted by eriko at 9:48 AM on April 21, 2006

According to the W-80 link in the [more inside], the selectable yield is not so complicated - the primary alone for 5kT, or the primary plus secondary for 150kT.

A 150kT warhead with a 2000km range isn't really that much different from a 450kT warhead with an unlimited range. I mean, look at all the cities in the world within 2000km of a coast.. Cruise missiles are a lot easier to intercept though..
posted by Chuckles at 12:42 PM on April 21, 2006

the primary alone for 5kT, or the primary plus secondary for 150kT.

5Kt is very low for a boosted primary -- unboosted fission weapons are in the 15-25Kt class. However, given that the bomber version of the W-80 has a .3Kt selection, that may be it -- the .3Kt would be the primary alone, the 5kt with boost, and the 150kt would be the secondary.

The big question is how does one switch them? A guess would be to use tritium as the fuel, and vent it, but most modern fusion weapons use Lithium⁶ or Lithium⁶ Deuteride, both are solid fuels. I guess you could remove that, remove part of the damper, which would keep the pressure from rising to fusion levels, or maybe you just have to move it back enough.

Alas, the picky details are very secret. The physics of nuclear weapons, even multistage ones, aren't hard. The engineering, however, is very complicated for anything more complicated than a HEU based gun type fission weapon -- the US and USSR first detonated implosion weapons, having assumed that gun weapons would just work. The UK, France, and apparently China never bothered to build them at all. The only know country to field gun based HEU weapons was South Africa.

Pakistan's test were gun-based HEU weapons, and they haven't shown the ability to build an implosion based weapon. India claimed that they had an implosion weapon, but the yield didn't match that. The 1998 India tests showed that they did have at least a boosted fission weapon, which they claimed was the primary for a two stage weapon, but the yields once again didn't match -- either it was just a boosted weapon, or the secondary failed to fuse. Still, at 40Kt, it wasn't a gun-weapon. Once you get the basics of the implosion trigger figured out, you're 90% of the way to a full two stage weapon, all the rest is engineer and test.

Thankfully, isotope seperation is hard, and the simple weapon designs demand rather-to-very U235 or Pu239. More complicated weapons are, in some ways, easier to acquire, since you don't need the highly pure fissionables, but then you have to engineer a very tricky weapon. That combination of facts is what makes getting nuclear weapons harder than the physics would show you -- indeed, with the right material, it's just a matter of banging rocks together.
posted by eriko at 6:48 AM on April 22, 2006