NASA's Curiosity rover is probably making some kind of awesome discovery on Mars as you read this.

The USSR launched Sputnik in October 1957. The tiny satellite spent three months circling the Earth, scaring Americans into a Space Race that culminated with the Apollo program that landed men on the moon.

Neil Armstrong made history when he became the first man to step foot on our natural satellite. The historic event was watched by an estimated 600 million people in 1969.

The footprints left behind by Apollo astronauts represent America's prowess in space technology. Their historic and sentimental value makes them some of the best candidates for preservation, an idea recently suggested in Congress through the creation of a national park on the moon.

Voyager 1, already the farthest man-made object from Earth, recently crossed the boundary into interstellar space. Along with its twin probe Voyager 2, the mission delivered some of the greatest photos of the outer solar system.

The twin Mars rovers Spirit and Opportunity long outlived their initial shelf life of three months. Though Spirit has reached its final resting place, Opportunity is still roving around and even making discoveries about ancient water on Mars.

A future space-shuttle-like rocket takes off from a launch pad, bound for the Helium-3 mines of the moon.

Much further in the future, mankind has formed a Star Trek-like Federation devoted to space exploration. Here an ship called the Explorer is prepped for another mission.