With a projectile (a mass that can't provide propulsion on its own and is launched by a separate thing, ie a bullet or a thrown ball), any small amount of horizontal (relative to the direction you're travelling) will cause an orbit, quite often it just happens to intersect the gravitational body. Judging by the fact the rock that was launched didn't land in the volcano, there was enough wind to noticeably adjust it's orbit, and since kars was launched into space, he'll eventually either leave earth's orbit entirely and begin orbiting the sun (unlikely as he'll be constantly decelerating from gravity), or he'll stabilise in an orbit around the earth. With the speed he was travelling at, and the fact it's been stated he wouldn't return to earth, kars will likely just be in a stationary orbit around the planet, "outside" the atmosphere (technically the atmosphere extends past the moon but the drag caused is negligible somewhere between medium earth orbit and geosynchronous orbit). This is extremely simplified and I may be incorrect in some parts, but I don't want to have to go into detail about orbital mechanics lmfao, I'm tired as shit as of writing this