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?

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?

How could an astronaut on a spacewalk begin to drown? Have NASA scientists discovered an asteroid that was converted into a spacecraft? What are the strange objects spotted when NASA sends a secret payload into space?

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?

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?

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 mysterious force is smashing a near-earth asteroid to pieces?

Something in space is attacking the brains of astronauts. What is it? Should NASA be worried about the sudden appearance of so-called space fireflies? Who is responsible for the bizarre glowing spiral in the skies over Norway?

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?

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.

Recently discovered documents reveal NASA's secret plan B for failure of the first moon landing, a Soyuz capsule carrying astronaut Peggy Whitson back to Earth vanishes without explanation and NASA’s Cassini mission unravels a three hundred year old.

Three cosmonauts die mysteriously as they re-enter Earth's atmosphere. A declassified document reveals a CIA plan to use a space disaster as a cover to start war and a NASA rover discovers clues that help solve a murder.

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.

Astronauts are evacuated when a mystery object is discovered hurtling towards the ISS, a NASA secret agent goes undercover to recover missing moon rocks & scientists struggle to find answers when they find a huge void at the edge of the solar system.

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.

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.

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.

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.

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.

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.

When NASA spots a something on Mars that resembles Stonehenge, they investigate what could have made this strange structure. Scientists discover a mysterious hole in Saturn's rings. An ancient tribe claims contact with alien visitors.

When the Soviet Union unveils its own space shuttle, the CIA hatches a secret revenge plot. Recent discoveries shed new light on the destruction of Sodom and Gomorrah. A missing nuclear weapon could threaten a NASA base in the Arctic.

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.

A mysterious object is orbiting Saturn, and it looks just like the Death Star. New evidence might shed new light on the mysterious death of Yuri Gagarin, the first man in space. When a cuting-edge satellite vanishes, fears of a space war escalate.

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.

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.

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.

When NASA begins a strange experiment to communicate with dolphins, experts investigate if it's a prelude to making alien contact. But some fear that such a discovery could have apocalyptic consequences.

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 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.