Thread by @elmihiro

Since people keep raising the DF-21/ASBM bogey despite the fact that most navies are pretty dismissive of the weapon, I thought it would be a good idea to do a thread on why the threat is far overblown.

https://twitter.com/paul_wilczynski/status/1074990887803985920

To see why, it is first important to understand the concept of a "kill chain". It is a system of sensors, command posts, and communications networks that allow a weapon to be directed at a target. The basic kill chain comprises of elements that, in succession, do the following:

- Detect a target. This could be an entire task force or a specific vessel within a task force.
- Identify the target.
- Generate a target track.
- Communicate targeting information to the launch platform.
- Launch the weapon.
- Guide the weapon to the target.

To successfully defend yourself against an attack, you have to "break" this kill chain. In naval engagements, there is a layered defence that helps do this. The means used include:

1. Stealth: I do not mean literal low-observability, but a combination of technology and tactics developed to hide task forces at sea or individual vessels within a task force.

The US Navy demonstrated such a capability in 1982, when a carrier battle group came within striking range of the Soviet coast and conducted operations completely undetected for four days.
navweaps.com/index_tech/tec…

Recently, a paper by a former Soviet Naval Aviation officer explained in a fair bit of detail how challenging it is to detect and track naval task forces on the high seas.
digital-commons.usnwc.edu/nwc-review/vol…

You need to throw all sorts of fancy technologies – satellites, ESM platforms, long-range patrol aircraft, surface vessels, land-based tracking stations, etc – at the problem and get them all to work seamlessly together. That's no mean task.

The officer basically demonstrated that the Soviets, even with all the resources at their disposal, could never truly solve the problem.

2. Air Superiority: Once you have control of the air, you could shoot down enemy airborne early warning and over-the-horizon targeting aircraft, rendering any long-range anti-ship weaponry practically useless.

3. Electronic Warfare: You could leverage your EW capabilities to disrupt the enemy's communications, jam his radars, create false returns, and/or spoof missile seekers.

Suddenly, enemy missiles don't know where to go, or if they do, there is no way to assure that they aren't wasted on, say, a fleet oiler masquerading as a carrier.

One way of tackling this issue is using an Imaging Infra Red (IIR) seeker with target matching algorithms. Lockheed's Long Range Anti-Ship Missile (LRASM) uses such a seeker, but it only works on slow-flying cruise missiles.

It doesn't work on ballistic missiles because the heat generated by re-entry would blind any optical sensor.

So for all the outcries of China developing a Wunderwaffe that can kill aircraft carriers from a distance, nobody seems to have articulated exactly how the Chinese reliably expect to:

- Detect and track a carrier on the high seas during wartime.
- Provide mid-course guidance to ballistic missiles.
- Achieve accurate terminal phase target discrimination and guidance.

Side note: using satellites to spot naval vessels doesn't work well in practice.

The Soviets tried doing so in the Atlantic, but were never truly able to generate reliable targeting data. Asif Siddiqi's paper [see link below] has a good account of the Soviet RORSAT system and its shortcomings.
faculty.fordham.edu/siddiqi/writin…

To expect that the Chinese will succeed at developing a means to reliably watch the (much larger) Pacific is stretching it.

Furthermore, there are the physical limitations of such a weapon to consider. To strike a target that moves as fast as a modern carrier, a missile would have to undertake sharp manoeuvres.

A ballistic missile's re-entry vehicle screaming through the atmosphere at hypersonic speeds would need *incredible* amounts of energy for these manoeuvres. Where is this energy going to come from?

Side thrusters and fins work well in executing minor changes in direction. And missiles equipped with such devices are reasonably good at hitting static targets on the ground. Even so, the accuracy is limited.

The Pershing-II IRBM, which was equipped with a maneuverable re-entry vehicle (MaRV), had an accuracy of 100 feet. Not nearly enough to hit a carrier-sized target. Why should the DF-21 be any different?

The other physical limitation is the structural strength. The sharper the manoeuveres, the greater the g-forces a missile is subject to.

Till date, no one has built a ballistic missile that can manoeuvere violently for precisely this reason. It will simply break apart. So again, why is the DF-21 expected to be any different?

And lastly, if these "carrier killers" truly live up to the hype, why haven't they been tested against a moving target? For a missile that is claimed to have been "deployed" for at least five years, the absence of a single real-world test seems . . . strange.