I'm nearly certain it's irrelevant but it does make me wonder where parts of the rockets used to launch the ballistic missiles that were recently put into hostile action would have landed.
Somewhere in between the launcher and the target. Ballistic missiles fly a near-parabolic sub-orbital trajectory. That also means that everything on the missile reenters and crashes (or reaches the target) within minutes of the launch. This is a matter or energy management. If your payload (the warhead) is going to land somewhere on Earth, why waste energy in flinging it on a high-velocity (possibly orbital) trajectory when that energy could be used to loft more of the payload (a heavier warhead) directly at the target?
There are a few cases where this concept of lowest-energy trajectory is not followed. One of them is a lofted-trajectory launch. The missile flies a higher ballistic trajectory than what's necessary to reach the target. This is sometimes used for missile tests or for target ranges less than the missile's maximum range. However, this is also a sub-orbital trajectory and behaves more or less the same as before.
Another case is the Fractional Orbital Bombardment System (FOBS) where the warhead enters a low orbit and then deorbits towards the target. Space debris situations like in this story (where the rocket body lands well away from the target, long after the launch) can possibly occur in FOBS launches. However, this isn't very energy efficient. It's main advantage is that it's harder to detect and intercept, since its orbital trajectory is much lower than a pure ballistic trajectory. Even then, some countries can knock them out in orbit using ASAT (anti-sat) detectors and interceptors. It's not that commonly used, except in combination with other technologies like hypersonic gliding and waveriding.
It's fairly niche here, but I would like to note that lofting can be more efficient than either a purely direct or ballistic trajectory -- one only needs consider the case of going higher in the atmosphere so as to have less air drag at extremely high velocities.
Can mean a higher speed, acceleration, and a longer range for the same payload.
In a sense, this is actually done with high velocity rocketry in general. Often most launch profiles involve a steep ascent before smoothing it out into a softer turn.
There are a few cases where this concept of lowest-energy trajectory is not followed. One of them is a lofted-trajectory launch. The missile flies a higher ballistic trajectory than what's necessary to reach the target. This is sometimes used for missile tests or for target ranges less than the missile's maximum range. However, this is also a sub-orbital trajectory and behaves more or less the same as before.
Another case is the Fractional Orbital Bombardment System (FOBS) where the warhead enters a low orbit and then deorbits towards the target. Space debris situations like in this story (where the rocket body lands well away from the target, long after the launch) can possibly occur in FOBS launches. However, this isn't very energy efficient. It's main advantage is that it's harder to detect and intercept, since its orbital trajectory is much lower than a pure ballistic trajectory. Even then, some countries can knock them out in orbit using ASAT (anti-sat) detectors and interceptors. It's not that commonly used, except in combination with other technologies like hypersonic gliding and waveriding.