The first moments of a shuttle flight do not inspire confidence.
Bolted to the bulbous external tank, with solid boosters port and starboard, the world's most sophisticated spaceship has a heavy look. It moves slowly.
As the shock waves frighten sea birds into flight, it rolls about its axis. It does not bore straight into the heavens, it arches over the ocean with the orbiter upside-down.
But when it begins its stunning acceleration it is a thing of surreal beauty.
When Challenger exploded on this "great day for flying," there was first around the launch site dead silence. Seconds went by, then came rising cries of anguish as the flaming debris fell, leaving thousands of sickly contrails.
Within minutes a whole country was as dazed as the New Hampshire schoolchildren hurriedly put aboard their buses and hauled away from the sight.
Later, one astronaut after another, one flight controller after another, would confess that in the private recesses of his own mind, he had feared the day.
Still, it seemed, fate had chosen the worst possible time.
Disaster struck the American space program at a moment when NASA was under unusual pressures.
James M. Beggs, the agency's administrator, a man highly regarded from the Washington headquarters to the flight control rooms at the Kennedy and Johnson space centers, was under criminal indictment in Los Angeles, accused of defrauding the government on a Pentagon contract while an executive of General Dynamics Corp.
He had announced plans in December to temporarily step aside to address his personal crisis. But he had remained at NASA to help William R. Graham, still new in the role of deputy administrator, take over the reins.
It was known by many in the agency that Beggs regarded Graham as unprepared for the job and that relations between the two were anything but cordial. Before NASA, Graham was an analyst at a Marina del Ray consulting firm that worked primarily with the Pentagon and the Department of Energy.
New to the agency, under the same budget pressures facing every department head in Washington, and leading a bureaucracy showing signs of fatigue, Graham faced a year in which flight schedules called for 14 shuttle missions, building toward a peak of 25 flights per year.
Then came the accident. Said a former NASA executive, "Graham's situation can only be compared to a man who takes over the Nuclear Regulatory Commission one day, and has a Three Mile Island episode the next."
At Cape Canaveral and Houston, engineers were under pressures of their own--from paying customers frustrated by launch delays, from the press, from ambitious launch schedules. In the days after Challenger went down, while ships and helicopters still searched the sea for the pitiful wreckage, space workers began to reflect.
"The shuttle is not an airplane and this is what they are trying to make it into," said Lyle Holloway, director of the Florida Test Center for McDonnell Douglas Astronautics Co. "Those poor people at Lockheed are working three shifts, seven days a week, to try to make this thing fly every four to six weeks. It's not made for that."
Some traced the growing pressure back to 1983 when the shuttle system was declared operational, others to the switch from Rockwell to Lockheed as the contractor preparing the orbiter for launch.
"The politicians in Washington made this happen," said a former Thiokol engineer who now runs a florist shop in Orlando. "I suppose it was for cost reasons. After all, you have to meet schedules with a program like this, you have to carry the payloads. So you begin to cut corners here and there."
It is a conjecture that NASA vigorously denies. Indeed, many experts still believe that the shuttle system is fundamentally sound, that the tragedy will eventually be laid to a random failure or to human error. Even critics such as Duke University's Alex Roland, who consider the spaceship an economic failure, do not fault it on safety grounds.
Such was not the case after the 1967 Apollo fire that killed astronauts Grissom, White and Chaffee at the same launch complex where Challenger began its journey. That tragedy revealed failures of management, a breakdown of quality control and an urgent need for changes in the spacecraft's interior.
Still, today many NASA veterans believe that without the catharsis of that tragedy, the United States would not have met the challenge of landing men on the moon before the end of the 1960s. It resulted not only in a rethinking of designs, but also a renewed commitment to safety and hard work by thousands of space program employees, and pledges of support from politicians.
NASA is hopeful that the Challenger disaster will once again be followed by renewal, and that the remaining shuttles will be flying again as early as six months from now.