If the weather holds up on Friday the final manned launch of the American space program, for now, will take place, the end of an era that began in 1969. The Atlantis will send four astronauts to work at the International Space Station. Once this flight is over, or if anything goes wrong, the Americans will have to turn to the Russian space program in order to get their astronauts home. As The New York Times points out, there are only four astronauts who'll fly into orbit. Normally a shuttle would fly six or eight astronauts up, but the Russians's Soyuz capsules that are now the only options for a trip home only carry three passengers. In the case of an emergency,   "two people would have to fly up and bring home the Americans one at a time." 

The space program began in 1961 as a dream in John F. Kennedy's eyes and then evolved dramatically in 1981 when the Colombia became the first reusable space craft. With the ability to fly in and out of space like an airplane, it was meant to forever alter the way humans were connected to the heavens. Here, the Washington Post offers a history lesson on the modern spacecraft:

CNN made a package about how far each of the five American shuttles have traveled:

The original goal of the space program was to raise the profile of America, and whether or not it did that is arguable. The space race of the 1960's provided a decent measuring stick for cold war enthusiasts. Dennis Overbye wrote an essay about growing up with the space program in The New York Times:

And so, soon we were in the era of the space truck to nowhere, easy travel to orbit and the sight of astronauts frolicking like weightless baby sea lions in the capacious shuttle decks and laboratories. Women, scientists, a congressman and a senator, not to mention an array of guest astronauts from other countries, logged time in orbit, performing scientific experiments, often on one another.

As so on Friday the last space shuttle will launch on its last, ultimate journey with only one destination in mind: landing back on earth. Weather permitting.