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?

Was the Moon landing faked? Images of Mercury reveal massive spider-like formations on its surface. Is it a geological formation or something ominous? A classified Space Shuttle mission ends in near-disaster. What was its mission?

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?

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?