Question

What is a moon pigeon?

Answer 1

The term 'moon pigeon' appeared in an official NASA report on the crisis that happened during the Apollo 10 Lunar lander's attempt to dock back with the command module.This moon pigeon is an extraterrestrial ship warning humans away from the moon.

Answer 2

 moon pigeon (which does look winged, and spaceship-like to me) is an extraterrestrial ship warning humans away from the moon. Some think that they jammed the computer system, some think they are benevolent and fixed it. Perhaps less imaginatively, some attribute the moon pigeon to a piece of debris from the mission or the leftovers of a previous mission. Some think it's a chunk of ice. Nobody really thinks it's an actual pigeon.