Thread by @ArmsControlWonk

Ok, we're on track to publish something on Ted Postol's analysis of North Korea's Hwasong-18 ICBM. But I wanted to do a short thread that illustrates just how incompetent Ted's analysis is.

I am aware of how this reads, but I’m not wrong. 😉

Ted says the Hwasong-18 is the Topol-M. So let’s start with some facts. The first stage of the Topol-M (RS-12M) is 1.86 m in diameter and 8.04 meters long. Russia had to declare this data under the START Treaty.

That makes the volume of the Topol-M first stage 21.85 cubic meters. The first stage weighs 28.6 tons or about 1.31 tons per cubic meter -- propellant, motor casing, insulation, nozzle, etc.

Ted says the Hwasong-18 is 2.2 m in diameter. That’s much bigger than the Topol-M at 1.86 m. Ted is wrong about the diameter of the Hwasong-18, but more important: 👏Ted does not understand the implication of his diameter for his own argument.👏

Ted is very bad at measuring things. He says a 2.2 m missile corresponds to a 22.7 m long missile “essentially the same length as ... the Topol-M..” When I re-measured his diagram, I realized that he didn’t measure the missile. HE MEASURED HIS OWN YELLOW ARROW.

Ted’s not off to a great start, but let’s humor him. If the missile is 2.2 m in diameter (it isn’t), that makes the first stage 9.04 m long for a volume of 34.4 cubic meters which is … 57 percent larger by volume than the Topol-M first stage.

To put this into perspective, Ted’s first stage would weigh about 45 tons – nearly as much as the 47.2 ton launch weight of the entire three-stage Topol-M. It should have occurred to Ted immediately that something was very, very wrong. Somehow, it did not.

It gets worse. Look at where Ted measured the end of first stage (below left). He didn’t measure to the bottom, where the exhaust comes out. He only measured to the white ring at the top of the skirt!

One of the things we teach students and new researchers when modeling missiles is to use multiple pictures. Being careful means looking at lots of pictures, doing things over and over again, and sharing with colleagues. It’s tedious, which is why a lot of people don’t do it.

When we measure the ENTIRE length of the first stage, it is now 10.02 m or 38.09 cubic meters. (Again assuming Ted's 2.2 m diameter is correct, which it definitely isn’t.) The first stage of Ted’s Hwasong-18 is now … 74 percent larger by volume than the Topol-M.

That is a lot of propellant. Ted's first stage now weighs ~50 tons, larger than the first stage of the US Peacekeeper ICBM and more than the full launch weight of the Topol-M. Somehow none of this occurred to Ted and whoever @BeyondCSISKorea asked to review the analysis.

@BeyondCSISKorea asked someone to review this right? They didn't just accuse a country of violating the New START Treaty and its MTCR commitments without a peer review, right?

Look, Ted is wrong about the size of the Hwasong-18. It is about the same diameter as ... a Topol-M. I agree with @RocketSchiller and others who note some similarities with Topol-M. Imitation is the sincerest form of flattery.

But Ted's analysis is incompetent.

Ted didn’t model this missile. Because if he’d simply worked out the volumes and propellant masses implied by his own measurements, he would have noticed that his model bore no resemblance to the Topol-M.

Ted can claim to be an expert all he wants—and denigrate us while he’s doing it—but he is comically bad at this. It doesn’t take much expertise to see the missile’s skirt through the hot exhaust and smoke. And it doesn’t take much to see the truth through Ted’s hot air, either.

Our more formal reply is here:
armscontrolwonk.com/archive/121866…

With contributions from: @madelineberzak @DuitsmanMS @dex_eve @miis_ford @sam_lair @triciawh1te and others.

@madelineberzak @DuitsmanMS @dex_eve @miis_ford @sam_lair @triciawh1te And @DnyAtDys.