A rut in the road is for some reason an orbit or trajectory. Maybe imagine a big ol' rut in the road. You drive at it at very high speeds, hit it, and fly into the sky at a trajectory that will send you into orbit. Now you're up in space, circling the earth, wishing you didn't drive so fast.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
Everyone was delighted to hear the news that the rocket entered orbit.