Watch it go by! 50 miles would be the closest approach of its hyperbolic orbit. It would have to graze the atmosphere to lose speed and fall to the surface.
Heh! I guess I misunderestimated how close that would be! It would be grazing the top of the Mesosphere ( where meteors burn up ... ) so you sure wouldn’t want it any closer.
Also, its predicted speed relative to earth during the encounter is 4 miles/sec, which is somewhat less than low-earth-orbit speed. This means to have a close approach, with this initial incoming speed, ( disregarding the atmosphere ) of 50 miles, its motion would be significantly affected by the earth, even though hyperbolic. So, this would be really really really close!
Maybe if you had said 500 miles, I would have been on a little firmer ground :-)