From the day Alan Shepard first shoehorned himself into the cosmic tin can of Freedom 7 more than four decades ago, astronauts have been America's Christopher Columbuses - sailors of the night sky planting the flag of American pride in the ether of outer space.
In the early hours of Saturday morning, however, the nation was reminded that historic achievement can come at high cost, as spaceflight remains one of the most dangerous professions on Earth.
It is a realization that has ebbed and flowed with the US space program itself. In times when peril seemed greatest, it accorded astronauts such as John Glenn and Neil Armstrong almost mythic status. Yet when feats of astrophysics began to seem almost routine, public attention has wavered.
In recent times, as millionaires and pop stars queued up for rocket-propelled thrill rides - and shuttles lifted off with a UPS regularity - the wonder of riding a missile into space perhaps has been too easily forgotten.
But Columbia, like Challenger before it, shows that in fact little has changed since the days of Apollo: Space remains the pursuit of those not afraid to sacrifice their lives for the sake of exploration.
"Astronaut training is so rigorous that you quickly realize how dangerous this is," says Howard McCurdy, a NASA historian. "Even though you might not be frightened, you are certainly aware of all the other ways things can go."
And there are many other ways it can go. Astronauts on Mir were famous for making duct tape the station's most precious commodity. Apollo 13 and Glenn's Friendship 7 nearly met with disaster, and a fire swept through the Apollo 1 capsule during a training exercise on the launchpad, killing three.
Yet until this weekend, the Challenger explosion was the only time NASA had lost crewmembers on a mission. Now, the number of fatalities during missions has doubled to 14 - roughly 4 percent of all the astronauts that have ever flown on US missions. Though the comparison is not parallel, the nation's most dangerous job, timber cutting, offers a measuring stick: It loses about 1 percent of its employees a year.
Still, for astronauts, the promise of space is undimmed. They, like former shuttle mission specialist Sally Ride, have a simple retort. "I just want to fly in outer space."
It is an enthusiasm and resolve that defines the astronaut corps. It is no mistake that two of the shuttle fleet - Discovery and Endeavor - are named after Captain James Cook's ships, or that the word Columbia is derived from Columbus. The astronauts see themselves as heir to that legacy - and all the peril and promise that goes along with it.
While training over months and years illuminates every conceivable catastrophe in detail, astronauts say it also offers the comfort of a routine. When she was sweaty-palmed and strapped in high above the launchpad, Ms. Ride says mundane procedures helped keep images of disaster out of her thought. "I put all my energy into focusing my mind on the details - what I needed to be doing," she says. "Looking at monitors. Do I have the checklist open to the right page?"
Indeed, if astronauts have one faith, it is in the system of checks and balances all around them - from the ground crew to mission control to the computers. When lightning struck Dick Gordon's Apollo 12 capsule, and warning signals turned the cabin Christmas-light red, he was clear on what to do. "The best thing we did was nothing," he says. "We just let the system work it out."
In many ways, not much has changed. Even though the space shuttle looks more like a proper airplane than the flaming garbage-can capsules that plummeted back to earth two decades ago, it is in many ways even more automated. Although more scientists are finding their way into the passenger chairs, the shuttles are still commanded and piloted largely by former test pilots like Mr. Gordon. "Spaceflight was just a further extension of my profession," he says.
As in his fighter pilot days, Gordon experienced many fraught moments. When his two Apollo 12 crew members were told to stay in the capsule while the launch was delayed, "the three of us took a catnap," he says. "You have to put [the risk] at the back of your mind."