Catch a wisp of the solar wind, take a picture of the early universe and study the climate of Mars with this guide to active unmanned missions.

Take a look back at the milestones in space exploration, including such historic launches as the Mercury-Redstone 3, Apollo 11 and John Glenn's return to space aboard the space shuttle Discovery.

Go back in time to see what the Earth was like when its surface was hotter and wetter, and watch flora and fauna evolve into modern plants and animals.