Michael Shaara

“ Ball came to join Steffens, staring at the robots through the clear plastic of his helmet with baffledly widened eyes. A robot moved out from the mass in the field, allied itself to him. The first to speak had remained with Steffens.
Realizing that the robot could hear every word he was saying, Ball was for a while apprehensive. But the sheer unreality of standing and talking with a multi-limbed, intelligent hunk of dead metal upon the bare rock of a dead, ancient world, the unreality of it slowly died. ”

“ There were robots here in the midst of a radiation so lethal that nothing, nothing could live; robots on a dead planet, living in an atmosphere of carbon dioxide.
The carbon dioxide brought him up sharp.
If there had been life here once, there would have been plant life as well, and therefore oxygen. If the war had been so long ago that the free oxygen had since gone out of the atmosphere—good God, how old were the robots? Steffens looked at Ball, then at the silent robots, then out across the field to where the rest of them stood. ”

“ Steffens saw it clearly for a full second, saw the dull ball of its head tilt upward as the ship came over, and then the hill was past.
Quickly Steffens called for height. The ship bucked beneath him and blasted straight up; some of the crew went crashing to the deck. Steffens remained by the screen, increasing the magnification as the ship drew away. And he saw another, then two, then a black gliding group, all matched with bunches of hanging arms.
Nothing alive but robots, he thought, robots. He adjusted to full close up as quickly as he could and the picture focused on the screen. ”