Who or What Is Knocking On His Spacecraft? | NASA's Unexplained Files

China's first astronaut gets a haunting experience as he hears an eerie knocking on the outside of his spaceship's door. There are no faults with his craft, so is he imagining it, or is there someone, or something, on the outside knocking to get in? Stream Full Episodes of NASA's Unexplained Files: https://www.discoveryplus.com/show/na... Subscribe to Science Channel: http://bit.ly/SubscribeScience Like us on Facebook:   / sciencechannel   Follow us on Twitter:   / sciencechannel   Follow us on Instagram:   / sciencechannel