Columbia was a white butterfly bolted to a bullet.
It was more robust than any other spacecraft ever built, more fragile than anyone dared acknowledge.
It was a daring departure from all that preceded it.
Columbia was the world's first reusable spaceship and the first to take flight on wings. It was the first to be sheathed in a reusable thermal protection system.
No single machine at the dawn of the 21st century was so complex, so consuming of national resources or so emblematic of a nation's vision of itself.
It was America rising.
The shuttle's very presence in orbit was an intimidating measure of the nation's industrial might and engineering prowess.
In so many ways, the shuttle was a machine made from the raw material of the American character.
Columbia embodied calculated risk.
Unlike any other U.S. rocket, its boosters were never tested in an unmanned orbital flight before being used to launch a human crew.
Promoted by NASA as a symbol of spaceflight, the shuttle's distinctive white delta-winged silhouette became a national logo, a trademark as recognizable as the signature swirl of Coca-Cola or the Nike swoosh.
It became a lapel pin and a squeeze toy, a cocktail coaster and a dorm room poster.
Throughout the 20th century, space travel was never far from the public mind, first as science fiction, then as reality.
Some visionaries straddled both realms. Wernher von Braun, the rocket scientist responsible for NASA's first successes, also helped Disneyland design its moon rocket and space station.
NASA gave itself a theme-park gloss.
Celebrated in space center museums and agency visitor centers, the achievements of U.S. spaceflight were as flat as a baseball card, as free of blemish as cereal-box art, packaged and marketed like a professional sports franchise.
In the glossy story that the agency presented to the public, there was never a misstep, never a second thought, never a miscalculation. No rockets exploded on the launch pad. No satellites vanished into the void. No astronauts died needlessly.
Unable -- or unwilling -- to embrace its full history in public, NASA may have numbed its own ability to heed the lessons of its mistakes.
Instead, accident investigators discovered, the agency was fated to repeat them.
By the time of its last flight, Columbia was itself a relic of the past.
Columbia was first launched in 1981 -- the year Britney Spears was born and MTV began to broadcast.
Nursed beyond its intended design life, the $1.8-billion spacecraft had become part of the nation's aging infrastructure, no different in that sense from the overstressed electrical power grid, crumbling bridges and outdated drinking water systems.
NASA, an aging bureaucracy, had grown less dynamic and more rigid with the passing years.
Every time Columbia went aloft, it carried a nation's dreams. It also bore a legacy of miscalculation, compromise and bad faith.
When it came apart in the air, more than astronauts died.
At first, investigators could only speculate about events that took place 40 miles above the Earth, where little behaves as it does at sea level.
With Columbia scattered across the Southwest, they had few physical clues at hand.
There was, however, no shortage of theories.
Astronomers speculated that an erupting solar plume of charged particles had damaged the shuttle's fragile electronics. Other experts wondered if years of weathering had corroded the shuttle's airframe or leached the strength from its protective sheathing.
Had the pilot made a mistake? Had a landing-gear door opened too soon, or had a tire exploded? Perhaps Columbia had collided with orbiting junk or a micrometeoroid. Ice falling from the external fuel tank could have damaged it.
A falling piece of foam insulation could have damaged it too.
Over and over, engineers replayed a blurred video of insulating foam splattering on the left wing during liftoff. Methodically, they studied all the circumstances: unusually strong wind shear, more swiveling of the rocket boosters than usual, violent sloshing of liquid oxygen within the fuel tank.
Everything had seemed well within design limits, they said.
Sean O'Keefe, the head of NASA, would later concur. He dismissed those who kept talking about foam as "foamologists."
It was O'Keefe's misfortune to arrive at NASA 13 months before the accident. A former financial watchdog at the Pentagon, he knew his way around budgets and Washington bureaucracy, but he knew little about spaceflight.
In the aftermath of the accident, the tasks he faced were all but irreconcilable.
He had to defend NASA while finding fault with it. He had to straighten out a human spaceflight program he only sketchily understood. And he had to persuade Congress to cover the costs at a time of war and soaring deficits.
The investigation would need all the credibility it could muster.