# How do we know the max range of North Korean missiles?

Every missile launch they have done has only had the missile go a few hundred miles. The maps that show Alaska and Australia in range of a NK ICBM have been all over the news, but is there any proof of this? How do we know just how far they can fire a missile?

If you know the mass of the missile, and can measure the height that it attains and the distance it covers between launch site and landing site, you can calculate other distances it would travel if the launch angle were different. This is high school physics. This would be if you assumed all the force of the rocket was applied at launch. It gets a little more complicated if the rocket is firing for all or some of the trajectory, but then you just need to be able to map the trajectory and the speed at various point along the travel path.

Missed the edit window… nothing that a simple computer simulation couldn’t handle. You could do the math without a computer, but it would just take longer.

There are also only so many ways to design and fuel a rocket, and it’s likely the US or Soviet Union figured anything NK would be capable of 60 years ago.

So by knowing the rough size of the rocket and by using the radar tracking observations, they know things like the speed, acceleration, staging time, etc… and can deduce a lot of other characteristics of the rocket, such as estimated range and payload.

Sent from my SAMSUNG-SM-G900A using Tapatalk

The mathematical bases of artillery go back hundreds of years. Tsiolkovsky, Goddard, and Oberth had the math for space rockets well under hand by the 1920s. They also worked on the only real variable, the fuel, and did calculations for both liquid and solid state fuels.

OK, this is literally rocket science and doing stuff like getting a rocket to land exactly where you want or shooting another rocket out of the air is very hard. Knowing the exact composition, weight, size, and thrust of a rocket an enemy is constructing in secret is hard. Figuring out how far it could fly once you have those numbers is the easiest part.

The latest North Korean missile went almost straight up, to an altitude of 1560 miles, before landing 580 miles from the launch site. From just these two numbers, it’s simple to estimate how far it would have flown if it was launched at a much shallower angle.

This all makes sense, but how do we know the missile would make it? North Korea is not known for reliable engineering. Who’s to say if they launched a missile at Alaska, it wouldn’t just fall apart or blow up over the Pacific?

Well, it could, and that does sometimes happen with North Korean missiles (or with ours, for that matter). But it’s no harder to launch the missile at maximum range than it is to do the up-and-down, so if they have a missile that can (at least sometimes) do the up-and-down, then it can also (at least sometimes) do the long-range flight.

The original question was about the range of their missiles (how far can they go if everything works?). Reliability is another question. Still, I don’t really see those in charge of keeping the US safe from an incoming NK missile saying “relax, it will most likely blow up before it gets here”.

If there’s anything different in how they test the missile v how they’d use it operationally, something could go wrong when it’s used operationally that wasn’t uncovered by the test. That’s among the reasons other countries developing long range missiles haven’t limited themselves to these very high trajectory short (‘horizontal’) range shots but rather tried to mimic operational use as closely as possible. Rather than try to figure out what they might be…just test it as you’d fire it. Which is still limited for example for US ICBM’s not being test fired in the same direction they’d go on real shots, though similar trajectory otherwise.

But a lot of the basic function is tested with the elevated trajectory tests. In fact in between panegyrics to Kim Jong Un every other line, the official KCNA article on a previous elevated trajectory launch explained it in a pretty matter of fact sounding way, saying the elevated trajectory was for the safety of neighboring countries, but it demonstrated the important capabilities including atmospheric re-entry as well as a longer shot would have. And it’s actually true more reaction would probably result from the missiles flying the over Japan (even outside the atmosphere) on max range trajectories, though there’s still a reaction from them landing in the ‘Sea of Japan’ (or East Sea as both Korea’s call it) in Japan’s EEZ on the elevated trajectories.

Geography means the US, Soviet/Russians and others haven’t had to fire lots of long range ballistic missiles over other countries to do lots of realistic tests. But quite possibly the NK’s will at some point. I think it was generally expected they would test the proto-ICBM on an operational trajectory rather than what they did.

And even if it does make the long trip, how accurate will the targeting be?

But OTOH, why won’t N.K. just buy a container ship bound for a large West Coast port, smuggle its weapon on-board on the high seas at night, and do a suicidal detonation, e.g., inside S.F. Bay?

Because the purpose of NK’s missiles is deterrence. An ICBM test demonstrates the capability to hit the US without actually attacking the US. This makes the US less willing to invade North Korea, because the stakes are higher.

If they smuggled a bomb to the US and detonated it, the result would be the complete opposite: it would provoke a US invasion of North Korea.

Plus, as a deterrent, an ICBM can be launched at the first sign of a US invasion, and it’ll be at its target in minutes.

A smuggled bomb can’t be sent anywhere quickly. Where would the NK military keep it? If it was securely stored in the country during the early stages of the invasion, now they have to smuggle it out past the US, SK, Japanese, etc. navies, who are certainly on high alert. If they keep the bomb outside the country, they risk it being discovered before it can be used. Then, they have to smuggle it into a US port, which presumably is going to have higher security during a time of war. Overall, the effect of the deterrent is much less certain if it has to be secrety stored and transported.

ICBMs are ballistic. The engines only fire at the beginning to accelerate the missile to several thousand mph. After that, the missile is just an inert projectile (until it reenters the atmosphere and explodes). It’s not going to blow up for no reason in the middle of the flight. The North Korean missile test already demonstrated that it can attain the necessary speed to coast to Alaska. All that needs to be changed is the launch angle.

Of course there still many other unknowns - e.g. how much payload this missile has, whether North Korea has a nuclear warhead small enough to be carried by this missile, whether that warhead can survive a ride on this rocket and operate correctly, etc.