Catherine DillIntercept Analysis

Comments

  1. Steve Hildreth (History)

    Not sure what to make of it, but the target strikes me as emulating a lofted ballistic trajectory. If so, is there an advantage to doing that if this was an ‘ASAT’ test? Or if someone can run the numbers what was the range they were trying to emulate if this was actually a BMD test? I know we do all sorts of these things when we test our BMD systems.

    • catherine (History)

      Hi Steve, You raise a very interesting point. But perhaps this question is better directed to David Wright, who wrote a companion post available at http://allthingsnuclear.org/chinas-january-2013-missile-defense-test/.

    • David Wright (History)

      Yes, this trajectory was lofted relative to a minimum-energy trajectory (MET). Launched on an MET, the target missile would have a range of 800 km and apogee of 200 km. Instead, this appears to have been lofted to have an apogee of around 350 km. A missile on an MET with an apogee of 350 km would have a range of about 1,400 km, but in that case the speed at intercept would be higher, so I’m not sure that was the point.

      There are a couple reasons China may have lofted the target. It might have wanted the target at higher altitude so it was easier to see by a distant tracking radar. It may also have wanted the intercept altitude to be in the neighborhood of 250 km since that is where it would expect to intercept a longer range missile. Intercepts for long-range US missile defense tests tend to be at around 230 km altitude. It may also be that putting the missile on more of a downward trajectory at intercept was intended to reduce the amount of debris that was kicked into orbit, although the speeds in this case of both missiles were low enough that there was likely not much concern about that.

      While the State Dept may call this an ASAT test, it doesn’t look very useful for that. The speed of the target missile was only 1.6 km/s at intercept, compared to a speed of about 7.5 km/s or so for a satellite in LEO. Similarly, the closing speed at intercept appears to have been about 5 km/s, compared to more than 10 km/s for an ASAT test. This looks more like testing hit-to-kill against a short or medium-range missile.

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