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aging infrastructure, no different in that sense from the overstressed electrical power grid, crumbling bridges and outdated drinking water systems.
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.
To provide it, O'Keefe appointed an Accident Investigation Board barely 90 minutes after Columbia was lost. For chairman, he chose Hal Gehman, an owl-eyed career Navy man who had led the Pentagon's investigation into the terrorist bombing of the destroyer Cole.