Space shuttle Columbia broke apart in flames over Texas Saturday, killing all seven astronauts just 16 minutes before they were supposed to land in Florida.
"It's gone," said a senior US official who spoke on condition of anonymity. The official said debris from the shuttle, spread across Texas and apparently some other states, had been positively identified. Though there was no official word from NASA, this official said there was no hope for either the shuttle or its crew.
Six Americans and the first Israeli astronaut were on board.
At Kennedy Space Center, the US flag next to the countdown clock was lowered to half-staff, although NASA officials have not confirmed the crew is dead.
President Bush returned to the White House by motorcade at midday. The president appeared on TV to express his condolences to the families of those who died on the space shuttle Columbia.
The Columbia apparently burst into flames on it approach to Cape Canaveral this morning, after completing a two week mission. There were seven astronauts on board.
Terrorism is not suspected, and a senior US official, speaking on condition of anonymity, said no threat was made and the shuttle was out of range of a surface-to-air missile.
Columbia had been expected to land in Florida at 9:16 a.m.
'Big Bang'
At 9 a.m., Mission Control lost all data and contact with the crew. At the same time, residents in eastern Texas reported hearing "a big bang."
Television footage showed a bright light over Texas followed by smoke plumes streaking diagonally through the sky. Debris appeared to break off into separate balls of light as it continued downward. NASA declared an emergency after losing contact with the crew and sent search teams to the Dallas-Fort Worth area.
The wives, husbands, and children of the astronauts who had been waiting at the landing strip were gathered together by NASA and taken to a separate place.
Residents of Nacogdoches, Texas, said they found bits of metal strewn across the city. Dentist Jeff Hancock said a metal bracket about a foot long crashed through his office roof.
"It's all over Nacogdoches," said barber shop owner James Milford. "There are several little pieces, some parts of machinery... there's been a lot of pieces about 3 feet wide."
Two hours after the shuttle had been expected to land, the giant screen at the front of Mission Control showed a map of the Southwest United States and what should have been Columbia's flight path.
Inside Mission Control, flight controllers hovered in front of their computers, staring at the screens after contact was lost.
First Landing Accident
In 42 years of US human space flight, there had never been an accident during the descent to Earth or landing. On Jan. 28, 1986, space shuttle Challenger exploded shortly after liftoff.
The shuttle is essentially a glider during the hour-long descent from orbit and is covered by about 20,000 thermal tiles to protect against temperatures as high 3,000 degrees.
On January 16, shortly after Columbia lifted off, a piece of insulating foam on its external fuel tank came off and was believed to have hit the left wing of the shuttle. Leroy Cain, the lead flight director in Mission Control, assured reporters Friday that engineers had concluded that any damage to the wing was considered minor and posed no safety hazard.
The shuttle was at an altitude of about 203,000 feet over north-central Texas at 9 a.m., traveling at 12,500 mph, when Mission Control lost all contact and tracking data.
Former astronaut John Glenn and his wife were watching on television at their home in Maryland.
"Anytime you lose contact like that, there's some big problem. Of course, once you went for several minutes without any contact, you knew something was terribly wrong," Glenn said.
First Israeli Astronaut
Security had been extraordinarily tight for Columbia's 16-day scientific research mission because of the presence of Ilan Ramon, the first Israeli astronaut.
Ramon, 48, a colonel in Israel's air force and former fighter pilot, had survived two wars. He became the first man from his country to fly in space, and his presence resulted in an increase in security, not only for Columbia's launch, but also for its planned landing. Space agency officials feared his presence might make the shuttle more of a terrorist target.
"The government of Israel and the people of Israel are praying together with the entire world for the safety of the astronauts on the shuttle Columbia," Prime Minister Ariel Sharon's office said in a statement.
Columbia's crew had completed over 80 scientific research experiments during their time in orbit.
Only three of the seven astronauts had flown in space before, the shuttle's commander, Rick Husband, Michael Anderson, and Kalpana Chawla. The other four were rookies: pilot William McCool, David Brown, Laurel Clark and Ramon.
Just in the past week, NASA observed the anniversary of its only two other space tragedies, the Challenger explosion, which killed all seven astronauts on board, and the Apollo spacecraft fire that killed three on January 27, 1967.
Oldest Shuttle
Space shuttle Columbia was the oldest in NASA's fleet and the first to enter the Earth's orbit in 1981. Saturday's voyage was its 28th trip into orbit.
Named after a ship that made the first American circumnavigation of the globe in 1792, Columbia flew into orbit in 1981. Four ships joined the fleet over the next decade; Challenger in 1982; Discovery in 1983; Atlantis in 1985, and Endeavour, built in 1991 to replace the Challenger after it exploded in 1986.
