Qian Xuesen's ballistics and Sanger's ballistics have their own characteristics and difficulties, and it is difficult to simply compare who is more difficult to defend. Here are some of their differences:
Qian Xuesen's ballistics: There are three stages in the launch of the missile, the first stage is the launch of the ball, which accelerates in a straight line and flies out of the atmosphere. The second stage is to fly towards the target, and this process is also the easiest to detect and intercept. The third stage is to reach the target above the target, drop directly and advance at full speed to strike at the target. Qian Xuesen's trajectory can be changed by changing the shape of the missile to become a wave-riding body, so that it can still fly at high speed with the engine turned off, and completely rely on air for propulsion, and the trajectory is completely unavoidable. This is also the reason why Qian Xuesen's missile is powerful, because even the person who launched it only knows the place of departure and the target, and does not know the trajectory in the middle. The thrust of the atmosphere can basically be regarded as a chaotic system, and the slightest impact of it will have a huge impact on the trajectory of the entire missile, so it is not possible at all.
Sanger's trajectory: Repeatedly entering and exiting the atmosphere to confuse radar, but as long as someone deliberately observes, it is not difficult to find the trajectory of Sanger's trajectory. Moreover, no matter how Sanger's trajectory changes, the direction of the target will not change, and this is also an insurmountable flaw.
In short, both Qian Xuesen's ballistics and Sanger's ballistics have their own unique characteristics and difficulties, which need to be analyzed and dealt with according to the specific situation.