It's something I remember reading in grade school. I was reading a bunch of Heinlein around the same time, but pretty sure it wasn’t him (it MIGHT have been). As well as I can remember: it took place on a moon or some kind of barren rocky planet. If it was a moon it must have been a big one, because gravity seemed pretty earth-normal. There was a human settlement, and the boy and the robot had left it to chase each other across the wasteland. I think the robot was bought as a household helper and had run away and the boy was trying to stop it and bring it back home. I think the robot was headed for a spaceport, but not sure. And the boy might have been a young man? What stands out in my memory starkly is a particular scene where the MC is standing or hiding next to a rocky outcrop and the robot is somewhere out in the darkness. It fires a laser at him, and it's done very realistically, no sound or impact, just a little red dot appears on the rock and a little thread of smoke curls up from it. I don’t remember if he needed to wear an atmosphere suit but obviously that would ratchet up the tension––a tiny laser hole in the suit would become deadly. I also recall much of the chase involved the MC constantly scanning the darkness looking for the telltale red wink that meant another laser strike. A red dot appears out in the wasteland, another simultaneously on or next to him, and then pain if it’s a hit. So the robot's presence was only shown that way for much of the chase. Any help would be greatly appreciated, thanks!