NASA's Unexplained Files

Strange flying objects have been caught on NASA’s cameras and astronauts have reported seeing UFOs. Some can be identified; others remain a mystery. We’ll reveal NASA footage and interview the astronauts and scientists.

Astronaut Leroy Chao’s spacewalk is interrupted by bright lights flying past. A flying saucer photographed from the Apollo capsule, dark shapes caught on camera shadowing the shuttle. The ideas are science fiction, but the incidents are science fact.

The Viking Lander may have found life on Mars, so why don’t we know about it? What is the most destructive force in the universe? How could a starship be seen in the Aurora Borealis? And what are NASA’s mysterious Moon Pigeons?

A UFO crashes in Pennsylvania. Was it a secret Soviet satellite or something far more dangerous? On Mercury, NASA finds the impossible: frozen water. A strange object causes a skyscraper-sized shadow on the surface of Mars's largest moon. What is it?

Was the Moon landing faked? Images of Mercury reveal massive spider-like formations on its surface. Is it a geological formation or something ominous? A classified Space Shuttle mission ends in near-disaster. What was its mission?

Are burning lights above Nevada and Utah signs of a secret space weapons project? What are the odd trails on the lunar surface near the Apollo landing sites? Does a strange space object spell disaster for the Space Shuttle crew?

Lost tapes reveal that Apollo astronauts heard unexplained transmissions on the far side of the moon, an amateur astronomer spots a strange disturbance in Martian atmosphere & an unidentified object in Earth orbit starts stalking Russian spacecraft.

Apollo 12 astronauts bring back something alive from the moon and NASA track an asteroid heading towards Earth but make a shocking discovery: it’s not an asteroid, but an object that’s artificial in nature.

Neil Armstrong goes into an unexplained spin. He needs to figure out what’s causing it, or he faces certain death. An Apollo 17 photo seems to show a military outpost on the Moon & could there be alien life swimming in the oceans of Jupiter’s moons?

Astronomers find evidence for incredible alien technology around a distant star. The first pictures of Pluto may show something moving across its surface. Apollo astronauts see something they can't explain as they approach the Moon.

A probe captures an image of a strange structure on Mars. Files from the first Apollo mission record an eerie sighting on the dark side of the Moon. A planet-eating star gives scientists a glimpse of Earth's terrible demise.

Geysers are discovered on a frozen moon, and NASA redirects a probe on a daring mission to detect evidence of life. An unidentified object is spotted approaching a near-earth asteroid. A future president is an eyewitness to a UFO.

A declassified letter written by President Kennedy demands the CIA share its UFO data with NASA. A bizarre pattern on the surface of Mars could be a coded alien message. Investigators are shocked to find a rocket crash-landed in a crater on the Moon.

Jupiter is far hotter than it should be, and scientists don't understand why. The Curiosity Rover finds something strange on Mars. Could it be a lost spacecraft or something far more sinister? Detectives turn to NASA for help with a murder cold case.

Two suns are photographed in the Indonesia sky -- a trick of the light or a sighting of our Sun's evil twin? Scientists are baffled by ghostly swirls on the Moon's surface. An astronaut disappears during his return to Earth.

When NASA discovers something strange on Saturn's biggest moon, experts investigate if aliens feeding on the electric atmosphere could be the culprit. The disturbing evidence points to a grisly apocalypse if these monsters ever make it to Earth.

When a former Area 51 insider alleges that the Roswell UFO incident was a nefarious Soviet conspiracy masterminded by Stalin, experts investigate if it was indeed an enemy plot against America -- or if the confession is just another cover-up.

When astronomers discover a rogue black hole speeding through the Milky Way, they investigate how much danger this cosmic monster poses to Earth, and what would happen if it ever entered our solar system.