For anyone who has watched, heard and felt a space shuttle heave off the pad and ride its immense column of smoke and fire into the heavens, the experience is beyond description. Mortal words don't do it justice and neither does television.

Yet man's astonishing feat of conquering space had become practically routine as the decades flowed by and the dreamers gave way to beancounters.

Space shuttles are workhorses in a stellar construction zone. They go up to build a space station and experiment with things like slime mold — advancing man's ability to work even more in space; missions to make further missions possible.

People down below — especially Americans living in their age of terrorism, now getting ready to fight another war, worrying about the security of their jobs — are never quite sure what all that wrenching and bolting and lab work mean to the earthbound.

Somewhere along the way, the cargo bay opened and the poetry of it all spilled out.

Even the amazing journey became somehow more ordinary.

Over 113 flights, space shuttles had traced a triumphal arc in the sky and glided safely home, all but one unforgettable day in 1986, 73 seconds after the Challenger's launch, and now another, 16 minutes before Columbia was to touch down.

Old astronauts, who made the dreams come true, lamented how space had lost its hold on the public imagination.

The drama was left to congressional hearing rooms where politicians argued about the NASA budget. Those who held the key to a million childhood dreams of travel in space were talking like this: "Cost challenges are presenting significant potential impacts."

Out went the temperamental visionaries at the helm. In came Sean O'Keefe, a man with budget sense, management skills and White House connections.

Earth's last communication with Columbia, invoking air in the tires, was as mundane as manned space flight itself seemed to have become in the public's view. "Columbia, Houston we see your tire pressure messages and we did not copy your last."

Then came the last mortal words from the shuttle: "Roger, uh..."

Dan Chandler, a middle school principal in Bristol, Pa., noted his students were not born when the Challenger exploded 17 years ago Tuesday. About 90 of them went to Goddard Space Flight Center in Greenbelt, Md., on Saturday to learn about satellites.

"It's become so old and routine that everybody now only pays attention to the mishap," he said.

When the Challenger blew up on Jan. 28, 1986, Deborah Provencal was watching, as a chaperone on a third-grade field trip that included Scott McAuliffe, the son of teacher Christa McAuliffe. Her hometown, Concord, N.H., and much of America was excited about sending the first teacher into space.

Provencal said this year, for the first time, she didn't notice the Challenger anniversary. "The day got past me," she said. "It was not until a day after or two days after that I remembered."

Everyone said Saturday that shuttle flights never were routine, not for a minute.

Everyone acknowledged that Americans had come close to taking the astonishing machines and their sojourners for granted.

"In an age when space flight has come to seem almost routine, it is easy to overlook the dangers of travel by rocket and the difficulties of navigating the fierce outer atmosphere of the Earth," President Bush said.

NASA executive William Readdy, a space traveler himself and a veteran of budget hearings, said: "Today was a very stark reminder that this is a very risky endeavor, pushing back the frontier."

"Unfortunately," he went on, "people have a tendency to look at it as something that is more or less routine. Well I can assure you, it is not."

In the tragedy Saturday, people summoned back the sense of adventure, vision and danger that was there all along for those who rode the pillars of smoke and fire. Bush talked about their "high and noble purpose in life," and their "courage and daring and idealism."

June Scobee Rodgers, widow of Dick Scobee, the commander of the Challenger, said it's still all about discovery and opening new vistas.

She said of Columbia's seven lost people, just as it was for Challenger's seven lost people, "if they signed up to fly with NASA, that must have been their dream."