In a tragic echo of the Challenger disaster, the seven astronauts on the space shuttle Columbia died yesterday when the spacecraft broke apart over Texas just moments before its scheduled landing and disappeared in a trail of fire, smoke and debris.
While families and friends waited expectantly near a Cape Canaveral runway for the end of an otherwise flawless flight, wreckage from the country's oldest shuttle was raining down on startled residents across hundreds of miles of Texas and Louisiana.
"We thought it was the sun shining off an airplane," said Doug Ruby, who described the scene he and his father saw while driving on a Texas road. "Then it broke up in about six pieces. They were all balls of fire before it went over the tree line."
As the crews' shocked families were quickly taken into NASA facilities, news of the disaster swept the country, producing a collective sense of mourning that reminded many of the reaction to the explosion of the Challenger on Jan. 28, 1986.
"You are not alone. Our entire nation grieves with you," President Bush told the astronauts' families in a broadcast to the nation after returning to Washington from Camp David. He said the crew and their families "will always have the respect and gratitude of this country."
At the same time, Bush said, "Our journey into space will go on. In the skies today we saw destruction and tragedy. Yet farther than we can see, there is comfort and hope."
Impromptu memorials sprang up at NASA facilities in Houston and Cape Canaveral, at the National Air and Space Museum in Washington, and at the Kennedy Space Center's astronaut memorial in Florida. Many flags were lowered to half-staff.
Milton Heflin, NASA's chief flight director, was near tears during an afternoon news briefing. Beside him, Ron Dittemore, shuttle program manager, was in a state of disbelief.
"This vehicle had performed flawlessly," Dittemore said. "It's a painful experience to lose our friends, realizing that things had gone so well, and turned out so badly."
Yesterday's accident, the second in-flight disaster in the shuttle's 22-year history, came 17 years and four days after the Challenger exploded during liftoff, also with the loss of all seven crew members.
NASA officials immediately grounded the agency's three remaining shuttles until the cause of the accident is found. Industry experts said the moratorium would likely last at least a year, but less than the 33 months that followed the Challenger accident.
At a briefing in Florida, where he had gone to greet the returning crew and their families, NASA Administrator Sean O'Keefe said somberly that the space agency had ordered preserved all data that might be useful in the investigation. All service on the other shuttles, as well as shuttle-related manufacturing across the country, was halted.
O'Keefe said an independent investigation board, assembled from the Air Force, Navy, Transportation Department and other federal agencies, would be formed to identify the cause of the disaster. NASA also launched a second, internal investigation. The same dual-track process was followed after the Challenger disaster.
Columbia's crew included the first Israeli astronaut, Ilan Ramon, 48, an air force colonel. But O'Keefe said there was no reason to suspect terrorism. Because of Ramon's presence and continuing turmoil in the Middle East, security surrounding Columbia's launch and landing was extremely tight.
The crew consisted of Rick Husband, 45, the shuttle's commander and an Air Force colonel; co-pilot William McCool, 41, a Navy commander; Michael Anderson, 43, the payload commander; mission specialists David Brown, 46, a Navy captain; Kalpana Chawla, 41, who was born in India; Laurel Clark, 41, a physician; and Ramon.
NASA investigators immediately rushed to Texas and Louisiana to gather debris, video and still pictures of the shuttle's breakup. The wreckage was scattered over hundreds of miles of countryside. Much of it lay smoldering, sometimes setting grasslands afire.
In Nacogdoches, Texas, Jeff Hancock, a 29-year-old dentist, said he found a chunk of debris in his office. "It came through the roof," he said. "It's about a foot-long metal bracket."
NASA urged residents who find shuttle debris not to touch it because of the toxic nature of shuttle propellants. They were urged instead to call local emergency personnel.
Collection of the debris is likely to be a crucial part of the inquiry. Investigators will examine it and try to reassemble the craft for clues to which parts or systems might have failed. Possibilities include the tiles of the heat shield, or the control surfaces, hydraulic systems and computers that guide the shuttle's return from space.
Search-and-rescue operations were launched as soon as NASA realized the shuttle had gone down, but it was soon obvious there was no hope of survivors.
Authorities in Texas said partial human remains had been found in at least two places in Sabine County. They were carried away in hearses.
A flight helmet, a maroon-and-black polo shirt and other fragments of clothing were found elsewhere in east Texas, along with pieces of metal, vacuum-sealed bags of cocoa and tea, and part of a parachute.
Reconstructing the day's events, NASA officials said ground controllers noted problems on board about seven minutes before communications with the crew were lost at 9 a.m. EST.
But the re-entry seemed to be proceeding well, Dittemore said. The spacecraft was making a series of computer-controlled banking maneuvers to reduce its speed.
This was also a period of maximum heating, he said. Friction with the air would have heated the shuttle's skin to 3,000 degrees Fahrenheit.
Several hydraulic temperature and pressure sensors in the shuttle's left wing went silent at 8:53 a.m., officials said, followed by sensors on the shuttle's left side.
A crew member acknowledged the loss of data by radio about 9 a.m., said Heflin, the flight director. "As far as I know, that was the last communication from the crew," he said.
At that moment, Columbia was 207,135 feet above northeast Texas, flying toward Cape Canaveral at about 12,500 mph - 18.3 times the speed of sound.
With increasing dread, ground controllers in Houston spent 16 minutes calling the shuttle repeatedly via ultra-high radio frequencies - "Columbia, Houston. UHF com [communications] check." But there was no response. Nor was there any sign of the shuttle on radar.
Liftoff damage possible
There was early speculation that foam insulation, seen breaking off from the shuttle's external fuel tank during launch Jan. 16, might have damaged thermal tiles that protect the spacecraft during its fiery re-entry.
Dittemore said flight managers and shuttle experts conferred immediately after the launch to consider the possibility of damage. But they judged "to a man" that the event "was not a safety concern."
In any case, he said, "There is nothing we can do about tile damage once we get to orbit."
"As we go forward with the investigation, we're certainly going to look at this," he said. But he asked the public not to jump to conclusions, saying, "it's still very early in the investigation."
The Columbia mission, designated STS-107, was dedicated to space science. Its crew worked in two shifts, 24 hours a day, on about 80 scientific experiments carried on board.
The scientific cargo included a cage of 10 white rats, sent aloft by Johns Hopkins School of Medicine scientists investigating the effect of prolonged weightlessness on cardiovascular systems.
Columbia was the oldest ship in NASA's shuttle fleet, delivered to Kennedy Space Center in March 1979. It was also the first to fly in space, a 54-hour test flight on April 12, 1981. Its final, fatal mission was its 28th, and NASA's 113th shuttle flight. Shuttles are designed to fly 100 times before they're retired.
Loss of the spacecraft leaves just two active shuttles in the NASA fleet - Atlantis, scheduled to fly March 1; and Endeavour, listed for a May 23 flight. A third shuttle, Discovery, last flew in August 2001. It is undergoing maintenance and modifications that began a year ago at Kennedy Space Center. No date had been set for its return to space.
Columbia itself was taken out of service in April 2000 for a $90 million overhaul. It returned to service in March last year, flying astronauts on a flawless servicing mission to the Hubble Space Telescope.
Allen M. Hoffman, a Boeing official who oversaw the 17- month overhaul, expressed concern about shuttle safety issues eight months after the work was completed.
"Is safety being squeezed out of the space shuttle program?" Hoffman asked in a letter published in the Los Angeles Daily News on Oct. 7, 2001. The letter expressed concern about changes in NASA's shuttle maintenance program to save money.
Reached at his office yesterday morning, however, Hoffman - Boeing's director of assembly and test operations at Air Force Plant 42 in Palmdale, Calif. - declined to comment on his letter except to say that "there were no safety issues" involving Columbia after the refitting was finished.
"We'd done a complete structural inspection," Hoffman said. "We have a whole facility full of employees who are in a total state of shock."
NASA has explored several options for replacing the aging shuttle fleet. One of the top candidates was the X-33, an experimental design that Lockheed-Martin had hoped would win NASA funding. NASA budgeted $841 million for the project, and Lockheed Martin agreed to spend another $220 million, with the first flights in 2005.
But on March 1, 2001, the space agency announced the project would not be funded. Instead, NASA planned to spend up to $2.1 billion over five years to upgrade the existing fleet.
Former astronaut Tom Jones, a Maryland-born veteran of four shuttle re-entries, turned on his television to watch yesterday's landing from his Virginia home.
At the moment the shuttle was lost, he said, a shuttle is essentially a hypersonic glider. With no engines with which to maneuver or fly once in the atmosphere, it can only slow down, lose altitude and land. There are no second chances.
When he saw that communications with the shuttle had already been lost, Jones knew immediately that something was wrong. Normally, he said, communications drop out only briefly during re-entry as voice and data streams are switched from a relay satellite to a direct link to Kennedy Space Center.
"Two seconds at most," Jones said. "Once you do that you're on a clear channel all the way down to the landing site. So I just said a couple of prayers and we just watched," he said.
Wire reports contributed to this article.