I haven't RTFA, but I expect that they aren't looking to challenge the laws of physics as much as test their engineering skills. It's pretty hard to hit something that far away and going that fast, especially if you want to hit it a particular way. They are probably testing to see if they can hit it just the way they want to so that they can actually make use of p=mv.
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If it's self sustaining, how do I stop it when I kill the engine?
I haven't RTFA, but I expect that they aren't looking to challenge the laws of physics as much as test their engineering skills. It's pretty hard to hit something that far away and going that fast, especially if you want to hit it a particular way. They are probably testing to see if they can hit it just the way they want to so that they can actually make use of p=mv.