Space travel is all well and good, but returning home to Earth provides another set of problems. Get ready to be quizzed about Yuri Gagarin's crash landing, cutting-edge shuttlecraft, and orbital space flight. Your quiz starts now...

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.

Astronaut Leroy Chao’s spacewalk is interrupted by bright lights flying past. A flying saucer photographed from the Apollo capsule, dark shapes caught on camera shadowing the shuttle. The ideas are science fiction, but the incidents are science fact.

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?

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?

Could spaceships be powered by atomic bombs? Can artificial rings encircle an entire star? why was Neil Armstrong’s transmission feed cut off when he spotted strange lights on the Moon? And how can lightning talk to itself?

What could make a NASA astronaut report seeing a flying saucer in the skies above a US Air Force test range? How have the swirling gases of Saturn formed a perfect Hexagon that has hovered above the planet’s pole for 30 years?

What would happen if we got a message from space? How would we react? Scientists and sci-fi writers, with cooperation from SETI and Carl Sagan's son, Nick, unravel the impact of this world changing event, forming an intriguing hypothetical scenario

How will humans react when an alien spacecraft is on its way to Earth? Will humans learn from aliens, or become colonial subjects? Scientists and sci-fi writers, with cooperation from SETI and Carl Sagan's son, Nick, unravel the impact.

The Arrival has ended. A swarm of small spacecraft depart their huge mothership, and hover in our atmosphere. The ships open their hatches, and deposit thousands of mysterious pods on the earth’s surface. Are they a message, a gift or a weapon?

A mothership the size of Texas is hovering over Earth and we're tired of waiting. We send a rover to explore, and what we find makes us question the definition of life. On Earth, the pods multiply, making contact with them unavoidable.

Go beneath the surface to understand forest fires, car exhaust, and the space station.

Discover the secrets behind the family car, titanium, and letters.

Find out the secrets behind nuclear subs, crash test dummies, and growing fruits and vegetables.

Discover how land mines are placed, how air boats work and how car warehouses work.

Discover the science behind black boxes, steam turbines, and racing cars.