The Uninvited Knock

The astronauts heard the knocking on the hull three days after leaving orbit. It came every ninety

minutes—exactly when they passed the dark side of Earth. No debris showed

on radar. No life signs. Still, the knocking followed them,

slow and patient. On the fourth night, Mission Control sent a final message: “We never cleared

you for launch.” The knocking stopped. Something outside whispered, through the radio,

“Then who did?”