A senior U.S. official said the spacecraft was "gone."
The seven crew members -- six Americans and the first Israeli to go into space -- were just 16 minutes from landing at Cape Canaveral, Fla., when the shuttle broke up at 207,000 feet. They had been orbiting the Earth for 16 days.
NASA lowered its flags at Cape Canaveral at 11 a.m. EST, but no official statement had yet been made about the fate of the crew. Officials at Kennedy Space Center said President Bush would be making an announcement.
Flags also were lowered at the White House and the Capitol in Washington.
White House officials said there were no indications that terrorism was involved. Bush was alerted to the likely disaster at Camp David, and Homeland Security Secretary Tom Ridge went to the White House to monitor the situation.
A senior U.S. 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 was at an altitude of 207,000 feet over north-central Texas at a 9 a.m., traveling at 12,500 mph, when Mission Control lost all contact and tracking data. The shuttle was aiming for a Florida landing at 9:16 a.m.
Television footage showed a bright light followed by smoke plumes streaking diagonally through the sky. Debris appeared to break off into separate balls of light as it continued downward.
Residents of Texas, Arkansas and Louisiana said they saw flames and heard a window-rattling boom at about 9 a.m., the same time all radio and data communication with the shuttle and its crew was lost.
Gary Hunziker in Plano, Texas, said he saw the shuttle flying overhead.
"I could see two bright objects flying off each side of it," he said. "I just assumed they were chase jets."
"The barn started shaking and we ran out and started looking around," said Benjamin Laster of Kemp, Texas. "I saw a puff of vapor and smoke and saw big chunk of material fall."
There were reports that debris had fallen in New Mexico, Texas, Arkansas, Louisiana and the Gulf of Mexico. NASA officials warned people not to pick up any debris, which was described as potentially dangerous.
Residents of Nacogdoches, Texas, said debris, including bits of machinery and pieces of metal, were found strewn across the city.
"It's all over Nacogdoches," said James Milford, owner of Milford Barber shop in downtown Nacogdoches. "There are several little pieces, some parts of machinery ... there's been a lot of pieces about 3 feet wide."
"It was like a car hitting the house or an explosion. It shook that much," said John Ferolito, 60, of Carrolton, Texas.
I was getting ready to go out, and I heard a big bang and the windows shook in the house," Ferolito said. "I thought it was a sonic boom."
It was the 113th flight in the shuttle program's 22 years and the 28th flight for Columbia, NASA oldest shuttle.
Inside Mission Control, flight controllers hovered in front of their computers, staring at the screens after contact was lost. 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 secluded place.
"A contingency for the space shuttle has been declared," Mission Control somberly repeated over and over as no word or any data came from Columbia.
In 42 years of U.S. human space flight, there had never been an accident during the descent or landing phase of a mission. On Jan. 28, 1986, space shuttle Challenger exploded shortly after liftoff.
Shortly after Columbia lifted off Jan. 16, 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.
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.
A senior U.S. official, speaking on condition of anonymity, said Saturday there was no threat made against the flight and that the shuttle was out of range of a surface-to-air missile.
"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 80-plus scientific research experiments during their time in orbit.
Only two of the seven astronauts had flown in space before, the shuttle's commander, Rick Husband, and Kalpana Chawla, the first Indian-born woman in space. The other five were rookies: pilot William McCool and Michael Anderson, 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 Jan. 27, 1967.
The Associated Press contributed to this report.
-taken from www.foxnews.com
What do you think? My dad just came running into my room and turned the tv on to 24 and heard space shuttle columbia desinigtarted over texas.
