NASA's Unexplained Files Episode Rating Graph

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.

A Russian probe discovers the lunar soil was disturbed before the US or USSR got there. Did Nazis arrive first? Have scientists detected a laser signal from a planet capable of supporting life? Is there a Bermuda Triangle of Space?

After Neil Armstrong's moonwalk, he led an expedition to the Amazon to find a legendary library that holds all knowledge of an advanced alien civilization. Experts ask if a close encounter on the moon's surface inspired Armstrong's mysterious quest.

After NASA's New Horizons spacecraft flies by Pluto, it encounters a strange alien world that shuts down the probe's computers, and experts investigate if this mysterious object is an alien spacecraft hiding at the edge of our solar system.

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.

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?

A strange discovery by NASA's Mars Curiosity rover suggests the Red Planet was home to an alien nuclear war 300 million years ago. Experts investigate if an extraterrestrial Armageddon transformed an earth-like world into the wasteland we know today.

The last humans to walk on the Moon discover something strange on the surface. A NASA scientist investigates a strange phenomenon responsible for horrific mass deaths. A landmark NASA mission threatens to destroy the reputation of an American hero.

Could NASA be responsible for a nuclear explosion on Jupiter? Could new evidence finally solve the mystery of the iconic face on Mars? What unknown force crashed a spacecraft from the Apollo program into the lunar surface?

Experts investigate if a nearby exoplanet could be the home to a alien civilization of strange, metallic monsters, after a new discovery confirms that life can thrive on such a strange world.

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.

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?

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.

A distant planet shows evidence of an Earth-like atmosphere, while a mysterious light suggests an atmosphere on the Moon. Have we found evidence of a crashed alien ship in the asteroid belt? Why are there "blueberries" on Mars?

British astronomers working for the CIA intercept Soviet photos of the moon. A malfunction on the ISS could poison its crew with ammonia gas. A startling image taken by a NASA probe points to evidence that life could exist on Mars.

Two cosmonauts fight for their lives while trapped inside a capsule in a frozen lake. A NASA scientist investigates the deadly Nazi secret that doomed the Hindenburg. NASA astronomers are spooked when the full moon starts affecting their experiments.

A discovery suggests the hellish clouds of Venus may be the origin of life on Earth. A bizarre sighting 2,000 years ago raises the possibility that Earth once had two moons. A scientist helps the FBI crack the 1996 Olympic bombing.

A probe carrying a message to aliens malfunctions as it enters deep space. A NASA mission goes disastrously wrong when an imposter breaches Mission Control. Astronomers may have found an invisible planet around a distant star.

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.

A chunk of the sun appears to have vanished. An ominous dark craft beneath the Space Shuttle Endeavour. Hubble spots thousands of unidentified objects traveling faster than light. Are we being watched?

When a Chinese moon rover breaks down, a NASA scientist points to a mysterious material that seemed to sabotage the Apollo missions, decades earlier. The Rosetta spacecraft finds a comet that appears to be singing.

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.

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?

Two astronauts trapped in the vacuum of space face an agonizing death; the first close up images of Pluto reveal an alien landscape, and residents of Houston struggle to explain videos of unidentified flying lights captured above their city at night.

Astronomers detect a potentially habitable planet tantalizingly close to Earth. A chance discovery at NASA reveals a top secret military space program. The Apollo missions bring back evidence that the moon may be rich in the building blocks for life.

An astronomer records an unusual signal from a distant star. FBI agents find classified documents at the home of a NASA scientist. When scientists discover strange DNA in the octopus, they examine if their origins could be alien.

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.

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.