Nuclear Friday: Standoff Range

The Long-Rang Stand-Off cruise missile  (LRSO) is the second most controversial part of the Obama-Era Stockpile Stewardship nuclear weapons program. I suppose I should say it’s by now the most controversial program because the B61 Mod-12 program is nearing completion. The Air Force has a pending order for the system and is scheduled to decide between two competing designs later this year. Readers of The Board might think that the LRSO controversy is over in an era when Trump wants to increase US nuclear capabilities. But there is some opposition to the program within the Trump cabinet. For instance, Secretary Mattis has discussed his doubts about the need for the LRSO. I think it’s likely the LRSO will be fully funded for next year and go into production.

I am still a bit troubled sometimes when I hear critics of the LRSO, which they usually refer to as the “stealth standoff” missile, describe it as if it has entirely new capabilities. It does not. The LRSO is only slightly more capable than the AGM-86 ALCM , which is a stealth standoff missile in its own right. The ALCM was first built in the late 70’s, and while capable, is nearing the end of its service life. The reason to start making the LRSO now is so that the US will have working cruise missiles at all fifteen years from now.

Now a case could be made that the United States could do without nuclear standoff range capability. The Board actually favors standoff capabilities over other systems and I will discuss why over the next couple of posts. But first, we need come to understand standoff systems as a general concept and take a look all the way back to the earliest nuclear armed standoff systems developed in the late 1950s. Arms control and strategic policy issues will have to wait til after a couple of history lessons.

Standoff Weapons, General Concepts:

So just what is a standoff weapon? In general, a  standoff range weapon is an air delivered weapon that is launched or released from outside the range of ground based defenses in the target area. Also, they are “fire and forget” weapons. They do not require that any attention be paid to the weapon by the pilot or any other crew member in the carrying aircraft after the weapon is launched or released.

Standoff weapons are usually air to ground guided missiles, but with the advent of the JDAM guidance package and similar systems, the dumbest gravity bombs can become standoff weapons.

Since I last discussed the B61 Mod-12 program in depth here at The Board I have since confirmed that it uses a modified JDAM system as suspected. That makes it a rare (unique?) exception to the general idea that nuclear standoff weapons are missiles.

We will now look into the history of the of the very first nuclear standoff range system.

I loved The AGM-28 Hound Dog:

As regular readers know, I began my study of nuclear policy at a very young age. SALT II and later the Soviet invasion of Afghanistan had us kids worried. There wasn’t any Internet back then, but as luck would have it, nuclear weapons were considered a wholesome subject for books that would appear even in elementary school libraries. Most of the books were from the late sixties, so I was obviously misinformed for a while about current US and Soviet deployments. For instance, I thought Hustlers were still a thing in the late seventies. I had no idea it was a widowmaker long since abandoned.

When you are eleven, you like things that look cool, even manifestly insane things. But sometimes looks aren’t deceiving. The AGM-28 was almost as good as it looked. This was the very picture I first saw of it:

STAagm28
Sweet Hound Dog, anti-flash white.

Again, I had the misapprehension that the Dog was still flying when I first learned of it. The AGM-28 had a fairly short service life of only thirteen years. It served well during those years and was considered for upgrades in the early seventies. It was phased out only because more capable systems were becoming available at that time.

The Missile Gap and the Real Missile Threat.

In the late fifties, the Democrats were considered the more hawkish party. With the launch of Sputnik in 1957 there came to be a perceived Missile Gap. This was not an unreasonable conclusion as the whole point of Sputnik was to create the perception that the USSR had ICBM capabilities when the US did not. And Khrushchev certainly did his best to create this perception both in the Kitchen Debate and addresses to Soviet and international media. The missile gap and increased funding for strategic defense was part of JFK’s 1960 presidential campaign.

Thanks to information from U-2 overflights, Eisenhower, and Kennedy’s opponent, Richard Nixon, knew the Soviets were incapable of keeping as many as ten R-7 missiles operational and usually kept only four on active alert.

There was no missile gap but there was a real missile threat, the SA-2 which would become in later variants the most widely used SAM to date:

STAsa-2

In May 1960 a U-2 reconnaissance plane piloted by Francis Gary Powers was damaged by one of these and Powers was captured. Soviet defenses had trouble hitting the fast and high flying U-2 with its small radar profile. Hitting a B-52 bomber would be much easier.

Luckily for SAC, there was already a system in development to address the SA-2, the AGM-28 which was dubbed the Hound Dog after the popular song. The AGM-28 was intended to be launched shortly after crossing Soviet defensive perimeters. The intended targets were targeting radars, forward air defense command bases, and the SA-2 launchers themselves. The bombers would nuke a path for the bombers to reach their primary targets. The Hound Dog was not stealthy by today’s standards, but was certainly difficult to track for the radars of the early sixties. It was also fast and could sometimes hide under the radar, though not nearly as well as later missiles could.

Innovations in the AGM-28:

The Hound Dog is a pilotless supersonic aircraft with a thermonuclear warhead. Its mission was simple, fly to the target ahead of the bomber and airburst to damage radars and missiles, or dive and detonate to turn a hardened command post into a crater. Its main innovations were the efficient W28 warhead and the compact navigation system. The fuel efficient engine came from the development of the Century Series fighters, and the airframe came partly from the ill-fated Navaho cruise missile.

The warhead from the Mk-28 series was the first truly modern thermonuclear warhead. The first H-bombs of the Teller-Ulam design were bulky and relied on tertiary fission from U-238 in a depleted uranium or tubealloy  (natural uranium) tamper for a substantial part of the yield. The Mk-28 was different. It had a much smaller fission primary than earlier devices, and because it had a smaller primary while still being able to initiate the fusion secondary, it needed only a very light tamper, or “jacket” as I like to call it, around the fusion secondary. This means it would generate almost no fallout in an airburst. They weren’t trying to make an environmentally friendly nuke, there would still be plenty of fallout in a ground burst, and maximizing fusion yield relative to fission yield was sought simply to make bombs smaller and lighter.

Still, it was pretty impressive to pack up to a little over a megaton in a package this small:

STAw28

Oh wait, you have no sense of scale here. So let me show you a picture of a B28 from the eighties. The 28 series was so good it was still around in the late eighties:

STAb28

Only about a half or a little more of that bomb is the actual nuclear device. It’s tiny compared to most thermonuclear weapons of the late fifties and early sixties. And the Hound Dog carried them in 1963.

The other innovation was the navigation system for the Hound Dog. It had an inertial navigation system that was just a somewhat smaller version of the of the same navigation gyros and computer used in the B-52 bomber that carried it. Here’s a link to how it worked, though I doubt you can figure out any more from it than I did. And the AGM-28 also had an astro-tracker a kind of automated celestial navigation system well beyond my understanding. There was even a data link between the computers on the bomber and the missile. This missile is part of how we got the Internet.

Video from Cape Canaveral:

And you knew it. There would have to be video. I would be betraying my fifth-grade self if there was not video. You may have read that Cape Canaveral in Florida was chosen for NASA’s mission to The Moon because it’s between 28-29 degrees North latitude to get a maximum boost from the rotation of the earth for the space race. Well yeah, the boost is nice, but you could get the same boost on the southern Texas coast.

Cape Canaveral was chosen for the Moon missions because at the time JFK made his famous speech promising to go to the Moon, Cape Canaveral looked like this:

STA canavaral
Closing that “missile gap” fast

In the late 40s Cape Canaveral was designated the Joint Long Range Proving Ground, though in the 50s and 60s most military folks called it the Atlantic Missile Range. It was chosen in the late 40s for testing captured V-2’s because much of the land had been seized by the feds during WWII for aircraft testing. Florida was not so densely populated back then and Canaveral was just the home of a few fishing villages and failed resort communities. But the resort communities had built roads before they failed in the thirties. There really was no better choice.

And so, here we are; Video of the first test of the AGM-28 in 1960. And it’s from Florida. A B-52 took off from Eglin AFB in the part of Florida that’s almost Alabama and flew all the way to the North Pole in the early Arctic summer around the same time as the U-2 incident in the Soviet Union. They timed their swirl near the pole to give them the stress of never seeing the sun set. The crew then fired after they got back to near Cape Canaveral one of the two Hound Dogs they carried fitted with a telemetry package and flight recorder in place of the not quite ready W28 nuclear device. Tracking and telemetry was recorded at the Atlantic range:

Things I learned from this video I did not know. There were concerns about weight and drag from the AGM-28. But this video says that Hound Dog engines can  be used  to boost  the bomber’s takeoff and they test the engines a few times in this video. But won’t the missile run out of fuel if they do this? Nope. The bomber can  pump fuel to the missile to make sure it takes off with a full load. Quite sophisticated.

Research Link:

Hound Dog alumni link documenting two broken arrow cases.

Next Week:

Why was the Hound Dog replaced? This has to do with the US experience in Vietnam, and the origin of stealth. Stealth came sooner than you think

Also, more context for The Board’s support for airborne standoff capability.

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