A look is taken at exclusive NASA footage and firsthand accounts of mysterious fly objects from astronauts and scientists are presented.
After NASA's New Horizons spacecraft flies by Pluto, it encounters a mysterious object that shuts down the probe's computers. Experts investigate what it could be.
Did Apollo astronauts hear unexplained transmissions on the far side of the moon? Plus, an astronomer spots a strange disturbance in Martian atmosphere.
Apollo 12 astronauts bring back something alive from the moon. Plus, NASA track an asteroid heading towards Earth and make a shocking discovery.
When astronomers discover a rogue black hole speeding through the Milky Way, they investigate how much danger this cosmic monster poses to Earth.
Experts investigate whether the Roswell UFO incident was a Soviet conspiracy masterminded by Stalin, or is the story just another cover-up?
Geysers are discovered on a frozen moon, NASA redirects a probe on a mission to find proof of life, and a future US President is eyewitness to a UFO.
Astronomers detect a potentially habitable planet tantalizingly close to Earth. A chance discovery at NASA reveals a top secret military space program.
Experts investigate if a nearby exoplanet could be the home to an alien civilization after a new discovery confirms that life can thrive on such a world.
Two cosmonauts fight for their lives, trapped inside a capsule in a frozen lake. NASA astronomers are spooked when the full moon affects their experiments.
A starling discovery suggests the hellish clouds of Venus may be the origin of life on Earth. Plus, did the earth once have two moons?
A strange discovery by NASA's Mars Curiosity rover suggests the Red Planet was home to an alien nuclear war 300 million years ago - could this be true?
A probe mysteriously malfunctions as it enters deep space. Astronomers find evidence of an invisible planet in a distant solar system.
A malfunction on the ISS could poison its crew with a deadly gas. A startling image taken by a NASA probe points to evidence that life could exist on Mars.
Jupiter is hotter than it should be, and scientists are baffled. There's a strange discovery on Mars and detectives ask for NASA's help on a murder cold case.
Witnesses photograph two suns in the sky over Indonesia - is this the first sighting of the Sun's dark twin that could spell imminent danger to Earth?
Geologists discover alien deposits on the Earth's surface - and the answer could shed light on the cause of the greatest extinction in its history.
A NASA probe captures an image of a familiar structure on the surface of Mars. What made 'Mars Henge'? Plus, how did an Apollo astronaut get sick on the Moon?
When the Soviet Union unveils its own space shuttle, the CIA hatches a revenge plot. Plus, a missing nuclear weapon could threaten a NASA base in the Arctic.
A NASA spacecraft suffers a malfunction in orbit - can its lone astronaut make it back to Earth? Plus, new evidence emerges over Yuri Gagarin's mysterious death.
When astronaut Leroy Chao's high-risk spacewalk is interrupted by bright lights flying past, it sparks a major investigation. Could alien life forms be to blame?
The Viking Lander may have found life on Mars. Meanwhile, how can a starship be spotted in the Aurora Borealis? And what exactly are NASA's mysterious Moon Pigeons?
The Hubble Telescope spots thousands of unknown objects travelling faster than light. Are we being watched? Or could we ourselves be aliens from another world?
A planet shows evidence of an Earth-like atmosphere, while a mysterious glowing light suggests the impossible: an atmosphere on the Moon.
Could spaceships really be powered by atomic bombs? Plus, why was Neil Armstrong's transmission feed cut off when he spotted strange lights on the Moon?
Test pilot Gordon Cooper is preparing to test a radical new landing system in a lakebed when two UFO's appear. Also, the mystery of Saturn's mega-hex.
A UFO crashes in Pennsylvania. Was it a secret Soviet satellite, or something far more dangerous? On Mercury, NASA finds the impossible: frozen water.
Images of Mercury reveal massive spider-like formations on its surface. Is it an odd geological formation - or something much more ominous?
How did pictures from the Hubble telescope make the comet of the century look like an alien spacecraft? Has earth already been invaded by alien organisms?
What are the mysterious trails on the lunar surface near the Apollo landing sites? Does a strange space object spell disaster for the crew of the space shuttle?
Something in space is attacking the brains of our astronauts. What is it? Should NASA be worried about the sudden appearance of so-called space fireflies?
An astronaut on a spacewalk begins to drown. How could this alarming event happen? Plus, have NASA discovered an asteroid that's been converted into a spacecraft?
Could NASA really be responsible for a nuclear explosion on Jupiter? Could new evidence finally reveal the truth behind the mystery of the iconic face on Mars?
A Russian probe discovers something has disturbed the lunar soil before the US or the USSR got there. But did the Nazis get there first?
Apollo 12 astronauts bring back something alive from the moon and NASA track an asteroid heading towards Earth only to make a shocking discovery.
An Apollo 17 photo seems to show a US military outpost on the Moon and is life in the oceans of Jupiter's moons? Plus Neil Armstrong faces real danger.
When a Chinese moon rover breaks down, a NASA scientist points to a mysterious material that seemed to sabotage the Apollo missions, decades earlier.
Newly discovered documents reveal NASA's secret plan B for failure of the first moon landing. And NASA's Cassini mission unravels a 300-year-old mystery.
Three cosmonauts die mysteriously as they re-enter Earth's atmosphere. Plus, a NASA rover discovers clues that help solve a murder.
Two astronauts trapped in the vacuum of space face an agonising death. Plus, the first close up images of Pluto reveal an alien landscape.
Astronauts are evacuated when a mystery object is discovered hurtling towards the ISS. Plus, a secret agent goes undercover to recover missing moon rocks.
When NASA discovers something strange on Saturn's biggest moon, experts investigate if aliens feeding on the world's electric atmosphere could be the culprit.
Neil Armstrong led an expedition into the Amazon seeking a library apparently made by aliens. Did a close encounter on his moonwalk inspire his quest?
When NASA begins an experiment to communicate with dolphins, experts examine if it's a prelude to making alien contact. Will it have dire consequences?