News sources reporting that a new Chinese ballistic missile, the Dongfeng-21D (DF-21), has the capability of hitting a moving aircraft carrier (up to a range of 900 miles away) heralds the demise of the aircraft carrier as the dominant force at sea, undermining the ability of the U.S. Navy to operate close to the Chinese coast:
The weapon, a version of which was displayed last year in a Chinese military parade, could revolutionize China's role in the Pacific balance of power, seriously weakening Washington's ability to intervene in any potential conflict over Taiwan or North Korea. It could also deny U.S. ships safe access to international waters near China's 11,200-mile (18,000-kilometer) -long coastline.
I am happy to say, though, that reports of the aircraft carrier’s demise are once again exaggerated. Just as the torpedo boat did not mean the end of the battleship, nor the submarine the end of the aircraft carrier, nor the anti-tank missile the main battle tank, nor the surface-to-air missile the end of combat aircraft, so the advent of an "anti-ship ballistic missile" will not mean the end of the aircraft carrier. I suspect, in fact, that it will prove less effective than a supersonic anti-ship cruise missile.
The reason is, the missile is only one part of an extended reconnaissance strike complex, consisting of sensor platforms, communications links, command nodes, and launch systems. The ocean is big, and the carrier is small. I was once on a COD flight that could not find the carrier, even though it knew precisely where the carrier was, because our navigation system was just a little bit out of alignment, and the carrier was operating in EMCON. Now imagine how hard it is to find a CVBG that does not want to be found.
Finding the target is the first step in the DF-21 strike process. The Chinese may use satellite (though I doubt we would let them do this very long), or long-range maritime patrol aircraft (which are most likely to give indications of target location by their failure to report back to base), or submarines (same problem).
Once the target is spotted, it must be reported back to base and a track file established. That means keeping it under observation for an extended period to establish base course and speed. Once a firing solution has been achieved, orders must be delivered to one or more firing units, which would then launch a salvo of missiles aimed at the place the Chinese think the carrier will be when the missiles enter their terminal guidance phase. Time of flight for 900 miles would be on the order of 12-15 minutes, depending on the trajectory. Launch warning from U.S. satellite systems would be nearly instantaneous, and in the remaining ten minutes or so, the carrier can travel 6-8 miles in any direction. This, combined with any errors in the track file, creates what is called an “error ellipse,” which increases over time.
To overcome the error ellipse, the DF-21 is presumably equipped with a maneuvering reentry vehicle and a terminal guidance seeker (either radar or IR). This not only drives up the cost and complexity of the missile, it creates additional points of failure that will reduce the overall reliability of the system. Assuming, however, that everything works as advertised, the terminal guidance seeker has a limited field of view (called a basket), and must be directed to a point in space that places the target within that basket. To ensure that this happens, the Chinese would probably fire a salvo of several missiles into the error ellipse, so that at least one missile would pick up the target.