We had thrown Karen's body out of the airlock on our way to the Moon. Disrespectful, maybe, but the vehicle was small, and who wanted to share it with a corpse, especially one that we all thought had been murdered? All but whoever of the three of us knew for sure and remembered how.
We didn't attempt to calculate her trajectory. Perhaps we should have. That way we would know if her corpse is orbiting the Moon, and if Paul's screams, every time hoarser and sadder, have only by coincidence the subtle regularities of orbits and guilt. If when he instinctively hides from the sky — he's no longer sane enough to have anything but instinct — there's nothing above him he has reason to hide from.