In May, when the space shuttle Atlantis was moved to its launch pad, STS-135's flight engineer, Rex Walheim, got a bit emotional.
"That is the most graceful, beautiful vehicle we've had to fly in space, ever, and it's going to be a long time until you see a vehicle roll out to the pad that looks as beautiful as that," Walheim said. "How can you beat that? An airplane on the side of a rocket. It's absolutely stunning."
If all goes as planned and the weather cooperates, at 11:26 a.m. ET those rockets will propel Atlantis into orbit and to one final rendezvous with the International Space Station. The mission will mark the end of a storied 30-year space program held up as one of America's greatest technological achievements and punctuated by two of the country's most painful tragedies.
About 750,000 people are expected to pour into the Space Coast of Florida to catch a glimpse of the final launch. With the shuttle, there's that kind of romanticism.
Part of it, of course, is the allure of space — the mystery of the unknown and the thrill of the conquer. Part it is what The New York Times' Dennis Overbye wrote about a couple of days ago.
He wrote about that April in 1981, when the shuttle program was in its infancy, when he stood faced with that iconic plane stuck to that giant fuel tank and it looked unmovable. But then, he writes, "The mountain did move on April 12, 1981... When the shuttle's solid-fuel booster rockets went off, it was like a second sunrise blasting our greasy faces. The Alps vanished atop a biblical tower of smoke and flame."
What he means with that kind of dramatic rhetoric is that the space shuttle program always seemed unreal. And in some ways, it was. As the astronaut Duane Carey told the AP on Tuesday, the shuttle program was a "magnificent failure" that fell short of the impossibly high bar that was put forth for it.
Yet, somehow, as Former President George H.W. Bush put it to the AP, the shuttle program "authored a truly inspiring chapter in the history of human exploration."
So, as we wait for that final countdown, take a moment to watch the video at the top of this post. It's a look back at some of the momentous video that came out of the shuttle program's 134 previous missions. It was produced by our colleagues Andrew Prince, Maggie Starbard and Marina Dominguez.
As we said, the weather may not cooperate today. If storms prevent a launch, NASA will try again on Saturday. The space agency is posting updates about the launch status here.
A little later this morning, Mark will be live-blogging as the launch time approaches.