The Nuclear Triad

I did a blog post about MAD - Mutually Assured Destruction, almost exactly a year ago.  The title of that post was "MAD History" (see  http://sigma5.blogspot.com/2016/08/mad-history.html).  I wrote the post because it had become apparent to me that a lot of people were not familiar with what MAD was about and why it was important.  The same thing has happened again.

A public figure about my age recently demonstrated little or no knowledge of what the "Nuclear Triad" is all about.  Someone quite a bit younger than him would have some kind of excuse.  Fear of a global nuclear war has justifiably receded in the minds of pretty much all of us.  So the importance of this kind of thing for the younger generation has understandably diminished.  But this person lived through fears of nuclear Armageddon, discussions of Global Winter, the Cold War, and the like.  It should have gotten baked into his DNA to know all about these kinds of things.  But it didn't.  So apparently we have a problem here.  I can solve it.

I actually spent a significant amount of time on the Nuclear Triad in my previous post.  I am going to recapitulate to some extent.  But I want to plow new ground for the most part in this post.  So I will.

The Nuclear Triad consists of three classes of vehicles for delivering nuclear weapons.  They are by airplane, by missile launched from a silo situated on land, and by missile launched from a silo housed in a submarine.  The airplanes came first.  Then the land launched and sea launched missiles arrived at close to the same time.  The sea launch system is a little newer.  And here I digress into history.  (I go into more detail here than I did in my previous post.)

The B-17 "heavy bomber" airplane was developed by Boeing in the run up to World War II.  The great depression was still on so cost was definitely a factor.  Once the War was well and truly under way Boeing developed the B-29.  It was more capable in every way.  It was bigger, slightly faster, could carry more bombs further, and flew a lot higher.  And, of course, it was a lot more expensive.

The main defense used by bombers at the time was to fly high.  The B-17 couldn't fly that high so it was pretty vulnerable both to Anti-Aircraft artillery firing "flak" and to fighter airplanes.  You can fly up to about 12,000 feet without supplemental oxygen.  The B-17 could barely operate much higher than this and tended to spend most of its time at a low enough altitude that the crew could forgo using their masks..  The B-29 could fly much higher so it was much more immune to flak and you had to have a much more capable (more expensive, harder to build) fighter to reach it.  The B-29 was the plane that was used to deliver the two nuclear bombs dropped on Japan.

The B-17 and B-29 were "prop jobs".  They used propellers to move them through the air.  That made it hard for them to fly really fast.  It is hard to make a propeller plane go more than about 350 MPH because to achieve higher speeds the tips of the propellers end up needing to go supersonic.  But the Germans introduced jet planes in a small way (luckily) during the War.  And jets were the future because, among other things, they didn't have the supersonic propeller tip problem.  So various jets were developed after the war.

They could go much faster.  They could also fly higher.  In several steps this culminated in the B-52.  It is bigger and better (and much more expensive) than a B-29 in every way.  But to a great extent it relied on the same defenses.  It flew high and fast.  (A number of "countermeasures" had been added to them at onetime or another but the foundation of their "survivability" was this traditional "high and fast" approach.)  The last B-52 was built in the mid '60s, roughly 50 years ago.

The Germans also came up with the V-2 rocket during World War II.  They didn't have much range.  They weren't that accurate.  And they could only carry a tiny bomb.  But it didn't take a rocket scientist to figure out that they were the future.  So a lot of money was poured into rocket development after the War.

The first thing that happened was a scramble for Nazi resources.  Roughly speaking the Russians got most of the equipment but the US got most of the people.  Remember, however, that at this time the US was spending a lot of time, money, and energy, on what became the SAC, the Air Force Strategic Air Command, and the B-52 bomber, a true technological marvel of its time.   They were so marvelous that the US Air Force flies them to this day.

So the Russians got the jump on us on the rocket front and launched Sputnik, the first artificial satellite.  As I noted before, if you can put a satellite into orbit you can put an ICBM warhead in your enemy's capitol.  Or so the thinking of the time went.  So the US played "catch up" but by the mid '60s they had the Minuteman ICBM.  This was a rocket capable of delivering a large nuclear weapon pretty much any place we wanted it put.  It wasn't all that accurate but then it didn't have to be.

It is not that hard to stop B-52s, the argument goes.  And the Minuteman is vulnerable because you know where its silo is.  If you can catch it before launch that's all she wrote.  So we desperately need, the Navy argued, something that is not as vulnerable.  By this time the capability existed to build a fairly large nuclear submarine.  One of them was cut in half and a middle section was added.  Into this middle section was place two rows of 8 silos.  And into each silo an MRBM (Medium Range Ballistic Missile) was placed.  And in a true feat of engineering magic a whole system was developed that allowed the missiles to be launched while the submarine was submerged.

The MRBMs did not have the range or payload of the ICBMs but the submarines could be positioned close enough to Russia for the whole thing to work.  And at the time that was good enough.  A second generation (the Ohio class) of submarines that could accommodate 24 silos and a bigger missile (the original missiles class was the "Polaris", the second generation missile was the "Poseidon")  was eventually developed and deployed, starting in the mid '70s.

And now for a small aside.  What's with this "B for ballistic" business?  Ballistic means unpowered.  The classic example of a ballistic missile is a cannon ball.  Once it leaves the barrel of the cannon it follows a "ballistic" trajectory.  It goes where gravity and air friction decide.  There are no other forces acting on it.  When it comes to ballistic missiles the business of figuring out where it will end up is a little more complicated but the general idea is the same.  The rocket motor burns for a relatively short period of time at the start of the flight.  After that ballistics determines where it is going to come down.

It made sense to use a ballistic design for early rockets.  It was the simplest approach.  But it's not the best way to go.  There is, for instance, FOBS - Fractional Orbital Ballistic Systems.  You put the warhead into low earth orbit where for technical reasons it is harder to shoot down.  Then after less than a full orbit (i.e. a fractional orbit) you have it re-enter the atmosphere and land where you want it to.  And the orbit doesn't have to be fractional.  The possibilities are nearly endless.  But in one of those unwritten "gentleman's agreement" things the US, Russia, and as far as we can tell all the other nuclear powers, agreed to make all their nuclear missiles ballistic.  Back to the main thread of this post.

We have had the triad in roughly the same configuration for 50 years now.  But while a lot has changed in the rest of the world, the nuclear triad has changed little.  This doesn't make sense, except perhaps in a MAD world.  So what's going on?  Let me address each leg separately starting with bombers.

The US has taken a couple of shots at upgrading its nuclear bombers.  The B-1 was supposed to replace the B-52.  The B-52 was subsonic.  That's not exactly fast if there are supersonic planes around.  So the idea was to do a supersonic bomber.  The B-1 is a lot faster than the B-52 but it turned out to not work much better at the "penetration" part of "penetration bomber".  By this time anti-aircraft missiles and radars and so forth had gotten much better.  The new idea was not to go high but to go low, really low, as in a couple of hundred feet off the ground.  This was literally "flying under the radar".  The B-1 was really terrible at this because it couldn't maneuver worth shit.  The Air Force ended up doing a major (and successful) refit to B-52s so they could hug the ground effectively.  Oops!

So the next try was the B-2.  By now "stealth" technology had come on to the fore.  The B-2 was slow, probably slower than a B-52, but it was very maneuverable and was almost completely invisible to radar and other airplane detection technologies.  But it turns out that the plane is wildly impractical.  You have to almost repaint it after each mission to keep it stealthy.  The Air Force has gotten some use out of the B-2 but not as a nuclear weapon carrier.

And then there is the whole "drone" thing.  In many ways the cruise missile is an early variant on the drone.  It is slow, very maneuverable, very hard to detect, and relatively cheap.  The only un-drone-like thing about it is that it drives itself.  And, as I indicated in my previous post, the early cruise missiles were nuclear capable.  I think that in the same way the Aircraft Carrier obsoleted the battleship in World War II the drone/cruise missile has obsoleted the heavy bomber.  But the Air Force is now in the process of spreading money around in an effort to come up with a B-3.  Will it be fantastically expensive?  Hell, yes.  Will it be an improvement on the alternatives?  I'm pretty sure the answer is going to turn out to be "no".  And in a tremendous irony, the B-52 turns out to be a great launch platform for cruise missiles.  Sheesh!

So how about ICBM's?  All they have done is get more vulnerable.  Both the US and Russia purposely built inaccuracies into their official maps at one time in an effort to effectively hide their missile silos.  If you aim for where the map says it is, you are going to miss it.  But GPS, cheap satellite imagery, etc. has put an end to that sort of thing.  The Russians know where our silos are to plus or minus a few inches.  We know the same about theirs.

The US took a stab at something called the MX missile system a number of decades ago.  This involved railroads and tunnels and a lot of other stuff.  The idea was to hide where the ICBMs were.  But it was never implemented and is now illegal according to various arms treaties.  So we have the same old missiles in the same old silos.  The only significant change is that the missiles GPS so their navigation is now dead on.

I talked about MIRVing, putting multiple warheads on one missile in my previous post.  Both US land and sea missiles were MIRVed.  (I presume the Russian missiles were too.)  But, also as I got into before, MIRVing is destabilizing and makes it difficult to stay within the limits of various treaties.  So a lot of de-MIRVing has now happened.

This has affected the missiles in the submarines but the submarine itself is little changed.  The Navy wants a new generation of submarine but I don't know how it will be much different.  Except, of course, for the whole "not 50 years old and falling apart" thing.  These new boats are bound to be expensive.  If you build one boat and put one unMIRVed missile in it then it becomes fantastically expensive.  So lots of missiles per boat and lots of MIRVing per missile makes sense as it reduces the cost per deliverable warhead.  But the Navy won't be able to do that so it is in a pickle.

There is what at first appears to be an obvious solution.  You can fit a nuclear capable cruise missile into the torpedo tube of a Los Angeles class "attack" submarine.  (This class of submarines is designed to do the kinds of things a World War II submarine did but do it in the modern world against modern defenses.)  But both the US and Russia have jumped through all kinds of hoops in order to make various nuclear weapon reduction treaties verifiable.  The primary thing that has been done is to separate things out into "obviously nuclear" and "obviously non-nuclear".  It must be easy to reliably categorize something as being "nuclear capable" or not.  And the operating assumption is that "nuclear capable" means "actually nuclear".

And it must be possible to use "national technical means" (satellites, etc.) to tell the two groups apart.  That means you don't put a nuclear equipped cruise missile into a supposedly "not nuclear capable" attack submarine.  Doing so would automatically put all attack submarines into the "nuclear capable" category.  They would all then have to be counted as "nuclear delivery systems".  And that means they would be counted against the "delivery systems" limit specified in the treaty.  We have, relatively speaking, a lot of attack submarines.  So we don't want them tangled up in nuclear weapons treaties.  And that means you can't take the obvious path.  And that makes things very complicated.

So to summarize:  The Nuclear triad consists of three kinds of methods of delivery of nuclear weapons.  They consist of bombers (airplanes), ICBMS (rockets in silos on land), and MRBMs (rockets in silos on submarines).  All three legs of the nuclear triad have failed to keep up with the times.

Taking bombers first, Cruise Missiles, possibly launched from B-52s (or alternatively launched from a not very heavily modified and, therefore cheap by military standards, commercial airplanes like the 767) look like a big improvement.  But instead of retiring nuclear capable bombers entirely, or taking the obvious alternate path of going with a modified commercial airplane, the Air Force is gearing up to spend a whole lot of money trying for the third time to come up with a viable alternative to the now more than 50 year old B-52.

The Navy's approach to their SLBM problem (the boats are old and break down frequently) is also to come up with a new version of the same old thing.  The new submarine would have a missile load similar to the first generation design that the Ohio class replaced.  The Ohio class boats were bigger and better.  I don't know if there is any new stealth enhancements that would make the new boats harder to detect than the Ohio boats are.  If such technology exists then it is going to cost a hell of a lot of money to move to it.

And then there is the math problem.  A lot of boats with a lot of silos, each containing a highly MIRVed MRBM, is hard to fit under the caps in current arms reduction treaties.  It will be almost impossible to do it if a new treaty lowers the limits.  I can actually see Putin going for a treaty update that lowers the allowable counts.  I can't see Trump going for it.

And the leg that has seen the least change has been the ICBM leg.  They have been MIRVed and GPSed.  But that's about it.  And I can't really see a change that it makes sense to make other than the obvious one or retiring a bunch of silos and missiles.

To me it makes sense to reduce the allowed numbers of nuclear weapons and delivery systems.  As I argued before (and I haven't changed my mind in the intervening year) going down to a number in the 200-400 range makes sense to me.  You can credibly play the MAD game with 200 warheads.  That will work for anything from North Korea to Russia or even China.

In this context a complete rethink of the whole "triad" thing, an artifact of history, politics, and technology, makes sense to me.  Start with a clean sheet of paper.  Figure out what makes sense in this new (modern technology and a limit of 200-400 warheads) environment.  Then figure out how to get from here to there.  Flexibility needs to be married to verifiability.  And it wouldn't hurt to throw in cost (it should be possible to make the whole mess much cheaper both to build and also to maintain than the current system) and reliability.

To pull this off, however, requires a leader who is thoughtful, careful, and detail oriented.  It will also be necessary for that leader to be committed to investing considerable effort and political capital in this sort of thing.  Donald J. Trump represents pretty much the opposite.  So it looks like our best option for the next few years is stasis.  Change nothing and hope he pays no attention.  Since he would likely to find the subject boring I think we have a good chance I will be being granted my wish..