Aug 30, 2016
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.


Dive into the mysteries of some of NASA’s most curious missions and explore stories of engineering achievement and human endurance. Each episode offers first hand testimony from astronauts, NASA mission footage, plus beautifully rendered CGI to bring to life these voyages that reveal unexplained sightings that have dogged many of NASA’s most famous missions.
Browse every episode and jump into details.
Aug 30, 2016
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.
Sep 6, 2016 · 1h
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.
Sep 13, 2016 · 1h
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.
Sep 20, 2016
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.
Sep 27, 2016 · 1h
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.
Oct 4, 2016 · 1h
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.
Oct 11, 2016 · 1h
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.
Oct 18, 2016 · 1h
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.
Quick answers about this season's release timeline and episode lineup.
NASA's Unexplained Files Season 4 premiered on August 30, 2016.
NASA's Unexplained Files Season 4 has 8 episodes.
The season opens with Season 4 Episode 1, "Pluto's Stranger Things". It aired on August 30, 2016.
Go to Season 4 Episode 1