Building the Space Station, Piece by Piece

On Wednesday, astronauts Douglas Wheelock and Tracy Caldwell Dyson will spend six hours floating outside of the International Space Station in the first of two planned spacewalks to replace a faulty coolant pump. Just another day at the office for the various crews who have called the ISS home since the year 2000.

By now, the quotidian goings-on at the ISS rarely make news, so accustomed have we become to the idea of an orbiting laboratory operating more than a couple of hundred miles from Earth. It was not always so. In fact, the idea for a space station goes back as far as the 19th century. It was a Romanian-German physicist who gave the idea its modern expression when Hermann Oberth wrote in 1923 about a wheel-like structure that would act as a kind of weigh-station for humans traveling to the moon and Mars. A few decades later, that vision became a reality.

In 1971, the Soviet Union launched the Salyut 1, the world's first space station. A couple of years later, the United States sent its first space station, the Skylab, into space. But for a variety of reasons, not the least of them budgetary, the Americans later abandoned a project to build a modular space station. With the end of the Cold War, these one-time rivals - joined by the Europeans, Canada and Japan - decided to pool their resources and pursue a joint program. The planning moved apace and in 1998, the first couple of modules of the International Space Station were joined together in orbit. Other modules later followed with the first crew arriving on board in 2000.