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. S3/Ep5
When a Chinese moon rover breaks down, a NASA scientist points to a mysterious material that seemed to sabotage the Apollo missions, decades earlier. S3/Ep4
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. S3/Ep3
Apollo 12 astronauts bring back something alive from the moon and NASA track an asteroid heading towards Earth only to make a shocking discovery. S3/Ep2
Lost tapes reveal Apollo astronauts hear unexplained transmissions on the moon, and a strange object in Earth's orbit starts stalking Russian spacecraft. S3/Ep1
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. S4/Ep5
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. S4/Ep4
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. S4/Ep1
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. S3/Ep16
The last humans to walk on the Moon discovered something strange on the lunar surface. Plus, a NASA scientist investigates a strange phenomenon. S3/Ep15
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. S3/Ep14
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? S3/Ep13
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. S3/Ep12
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. S3/Ep5
Astronomers detect a potentially habitable planet tantalizingly close to Earth. A chance discovery at NASA reveals a top secret military space program. S3/Ep4
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? S2/Ep3
A UFO crashes in Pennsylvania. Was it a secret Soviet satellite, or something far more dangerous? On Mercury, NASA finds the impossible: frozen water. S2/Ep1
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? S4/Ep8
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. S4/Ep4
When astronomers discover a rogue black hole speeding through the Milky Way, they investigate how much danger this cosmic monster poses to Earth. S4/Ep2
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. S4/Ep1
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. S3/Ep16
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. S3/Ep14
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? S3/Ep13
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. S3/Ep12
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? S3/Ep11
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. S3/Ep10
A potentially disastrous fuel leak forces three astronauts to make a risky return to earth. And a NASA lunar probe reveals a mysterious crashed craft on the moon. S3/Ep9
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. S3/Ep8
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. S3/Ep5
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. S3/Ep3
Apollo 12 astronauts bring back something alive from the moon. Plus, NASA track an asteroid heading towards Earth and make a shocking discovery. S3/Ep2
Did Apollo astronauts hear unexplained transmissions on the far side of the moon? Plus, an astronomer spots a strange disturbance in Martian atmosphere. S3/Ep1
Astronauts are evacuated when a mystery object is discovered hurtling towards the ISS. Plus, a secret agent goes undercover to recover missing moon rocks. S3/Ep8
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. S3/Ep5
When a Chinese moon rover breaks down, a NASA scientist points to a mysterious material that seemed to sabotage the Apollo missions, decades earlier. S3/Ep4
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. S3/Ep3
Apollo 12 astronauts bring back something alive from the moon and NASA track an asteroid heading towards Earth only to make a shocking discovery. S3/Ep2
Lost tapes reveal Apollo astronauts hear unexplained transmissions on the moon, and a strange object in Earth's orbit starts stalking Russian spacecraft. S3/Ep1
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? S2/Ep7
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? S2/Ep6
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? S2/Ep5
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? S2/Ep4