Fifty-five years ago on October 4th, the Soviet Union launched Sputnik. Twelve years later two astronauts landed on the Moon and returned to Earth. Today humans occupy the International Space Station for long periods of time studying the effects of space on our physiology while robots

In light of the dramatic achievement of SpaceX last week in being the first private company to successfully launch a payload into low-Earth orbit and rendezvous and dock with the International Space Station, let’s return to the challenges that lie ahead of us in the 21st century