The solar system is filled with millions of small bodies such as asteroids and comets. Some of these objects have impacted Earth in the past, and some may do so in the future. In order to ensure humanity's continued safety from a potentially catastrophic asteroid impact, we must develop techniques to push these objects away from Earth. One such method is the kinetic impact, which involves sending a spacecraft to collide with the threatening object and push it off its Earth-bound course. This work improves the kinetic impact method by helping to select the target site on the surface of a threatening asteroid that minimizes its Earth impact probability after the deflection. This is achieved by mapping gravitational keyholes onto the surface of the asteroid. If an asteroid passes through a keyhole, it will eventually impact Earth at a future date. Therefore, we must account for them when deflecting any asteroids. Using the new method presented here to design future kinetic impact can help ensure that the asteroid doesn't return on an Earth-impacting trajectory after the initial deflection.