There was a brief period in the not too distant past when it seemed that mankind had explored all there was to explore. There was no body of water we had not sailed, no mass of land we had not set foot on. The entire world was mapped, from pole to pole, from the Atlantic to the Pacific, and everything in between. We had explored it all. That is until the 1950's, when we set our sights on the grandest frontier of them all: Space.