Using calculus has the implication that this topic deserves serious attention, so pardon me for making us of plebeian math.

Utilizing the magic of trig and the assumptions taken from the FAQ... for an impactor to hit the side of the moon facing earth without intersecting it... the object must approach the moon from an angle between 0 and 26.4 degrees below the horizontal on the side nearest the rim. That is assuming that the the moon sits at the midway point between the center of the disk and outer rim (12,000 miles to the center/12,000 miles to the outer rim). Since the moon has almost no diameter relative to anything important, I treated it as a point. Obviously, if the moon is hovering on one side of the earth, the objects angle on the far side would have to me much shallower (less than 9.5 degrees) to impact it.

Parameters are as follows:

Earth Radius = 12,000 miles

height of moon relative to earth = 3,000 miles

angle of earth to moon = 90 degrees, obviously!

For comparison purposes, under the RE theory, the earth only blocks an arc equal to 1.9 degrees worth of surface area at any given moment. (Earth radius being 6.366km, distance to the moon, 384,000km)