Its a recon aircraft used to locate NK forces. If the aircraft's sensors don't know precisely where the aircraft is, then they are not able to determine the location of the "enemy" signals that they detect, hence the mission is no longer possible and there is no reason to continue flying it.

The Falcon vehicle is just a glider. There might be a second stage rocket that ignites after separation from the Minotaur IV rocket, but there is nothing exotic like a scramjet. What they are testing is the ability of the Falcon vehicle to glide and maneuver unpowered at high-hypersonic speed.