The 80 experiments on the agenda for Columbia's 28th flight had no urgency. Many were high school student projects.
Like a sideshow performer juggling chain saws, NASA could not afford to break its rhythm of launch and recovery.
In the third-floor crew quarters several miles from Launch Pad 39A at Kennedy Space Center, seven men and women sat in chairs while technicians helped them don orange pressure suits.
Air Force Col. Rick Husband, 45, the crew commander, gave a thumbs-up with both hands.
With him were Navy Capt. William McCool, 41, the shuttle's pilot; Air Force Lt. Col. Michael Anderson, 43, payload commander; Navy Cmdr. Laurel Clark, 41; Navy Capt. David Brown, 46; and Israeli Air Force Col. Ilan Ramon, 48, his country's first astronaut.
Kalpana Chawla, 41, was the only civilian in the crew. It was her second flight. She could not stop smiling.
As they disappeared into the bulky flight emergency suits, seven individuals became a regulation space shuttle crew — living components of the vehicle that awaited them.
They had a last meal and a last walk and last waves before disappearing into a hatch high on the streamlined white leviathan.
Technicians locked the hatch.
After 112 flights, the aim of the space shuttle was no longer so compelling, nor was its place in the American imagination so sharply defined.
The shuttle had been upstaged by science's maturing vision of space and time.
In the decades since Columbia was on the drawing boards, scientists had discovered the universe to be much more exotic than anyone had known.
Wormholes pierced its fabric. Black holes drank light and consumed galaxies. Space had been sliced into so many dimensions that theoretical physicists had trouble counting them all.
Instead of only one solar system with planets, astronomers had discovered dozens.
Dwarfed by such mysteries, the shuttle became a measure not of mankind's mastery of space, but of its limitations.
At the dawn of the 21st century, humanity was marooned on the shore of an ethereal ocean too broad to cross.