You’re assuming “they” had sufficient warning to “do something” about the impact. Assuming also that “they” were able to detect, and track the detect, and predict the crater location of the inbound object.
That’s a big kaboom. There was a detectable impact in Greenland sometime in the 20th century, don’t force me to look it up, because I will.
Air Force says no damage from Greenland meteor
Washington Examiner | 2-3-2018 | Travis J. Tritten
Posted on 8/3/2018 9:23:45 PM by waterhill
http://www.freerepublic.com/focus/chat/3676366/posts
The first half of the article was ridiculously wrong.
The author claimed the meteor “struck earth” 43 kilometers “north” of the air base.
I went back and read the graphics.
The meteor exploded.
43 kilometers ABOVE the air base.
At 54,000 mph.