Correct. You just have to hit it B4 it is right on top of you.
Well, I’d aim one a long ways out - try to get a little momentum change sideways. Or slow it. Or speed it. Only thing that matters is changing the mass (by breaking it up) and changing the momentum - by a little itty bitty bit. But do that a long way before imapct.
Then have the second hit.
Then the third.
Then the fourth.
Then the fifth. Send another 27. Blow them up if yo need to. Let them coast by if the thing is already split up or is off-course.
Most of the impactors will be comets. Rather fragile, but even one impact on Jupiter caused a black wave larger than three earth diameters.