You Might Want to Know - ICBMs Arriving, III. Becoming Rotten with Perfection, The Minuteman III
V. Becoming Rotten with Perfection, The Minuteman III
In Spring 1970, a few months after I stopped being a lawyer and went to Laramie to live, preparations began to put into service the newest model of our Minuteman, the Minuteman III. The Minuteman III would have even better guidance and a smaller CEP than the Minuteman I and II and a new feature that no ICBM anywhere had had before. Each missile would have multiple warheads on it, three in this case. Each warhead would be housed in re-entry vehicles called Multiple Independently Targetable Re-entry Vehicles. The MIRVs could be directed to three different targets.
Now that was a great idea, wasn’t it? President Nixon and Henry Kissinger must have thought so when they approved it. It would be like having three missiles where we’d had one before.
The Russians would figure out how do this too before long, I suppose. Except for that Sputnik satellite when I was in high school, and their hitting the moon with a rocket before we did, and their getting their cosmonauts into orbit before we did, we seemed to be doing most new things first, especially when it came to nuclear weapons.
Soon afterwards, we’d hear that they also had done it.
The new warhead we’d be using in the MIRVs that we’d have on the Minuteman III was the W62. We’d started to manufacture it in March. It was our lightest thermonuclear warhead yet, weighing only two-hundred fifty-three pounds. With its re-entry vehicle, it would weigh seven- or eight hundred pounds, but that was still less than a tenth of what Little Boy had weighed. Each W62 would yield one-hundred seventy kilotons, over eleven times what Little Boy had yielded. That meant its yield-to-weight ratio was four-hundred twenty times better than than Little Boy’s. The fireball of each W62 would cover about a square mile. The radius of the CEP for each warhead was just eight hundred feet, less than three football fields.
And remember: you could multiply the effect of the W62 by three for each Minuteman III missile.
We weren’t worried by how much less the W62 yielded, only one-hundred seventy kilotons, compared to, say, the W53 on the Titan II, which yielded nine megatons, almost fifty-three times more. The three W62s on the Minuteman III would yield a total five-hundred ten kilotons, only thirty-four Hiroshimas. But we’d figured out that the three W62s would do much more damage than would one warhead with the same total yield, maybe seven times more. Which got it up to three and a half megatons. Plus, with an eight-hundred foot CEP, even one-hundred seventy kilotons, eleven Hiroshimas, would probably be enough for most jobs you could think of.
By about 1973, we discovered that the MIRV idea wasn’t working out well. The Russians had developed MIRVs too now and had also begun to test a great big ICBM, the SS-18, that would be able to carry not just three MIRVed warheads, like our Minuteman III, but ten, maybe even fourteen of them. Each of them would have a yield maybe twice that of the W62 we had on the Minuteman III.
The SS-18 could also carry, we thought, one huge warhead that yielded not a measly nine megatons like the W53 we had on our Titan IIs but twenty megatons. More than the largest device we’d ever tested, the Shrimp, in Castle Bravo, that yielded fifteen megatons. Which wasn’t even a deliverable bomb.
You don’t suppose that before we produced the first MIRVs, we might have been able to agree with the Russians that neither of us would develop MIRVs, do you? Maybe not. The Russians already knew that their ICBMs could carry larger payloads than ours could. They would also have known, then, that something like MIRVs would give them an advantage.
In any case, we hadn’t tried to agree with them not to do this. And now, in 1973, here we were.
I’d come to Laramie to live in 1969. By 1970, I guess most of us in Laramie knew we had ICBMs over there outside Cheyenne. A student I had in a Freshman Composition class I was teaching wrote a paper that described someone like himself looking out to the east up over the Laramie Range one day and seeing rocket contrails arcing into the sky. I don’t remember how his essay ended or what his point was if he had one. The image did stick with me.
Next: We Weren’t Done Yet