The space shuttle Columbia broke apart in flames over Texas on Saturday only minutes before it was supposed to land in Florida.
U.S. President George W. Bush confirmed that the shuttle had been destroyed, killing all seven crew members. There were six Americans and one Israeli on board Columbia.
"Columbia is lost," he said. "There are no survivors."
Authorities confirmed late Saturday that human remains were recovered in a field near Hemphill, Texas in the northeast part of the state. CNN showed footage of investigators recovering the remains, which are believed to be a member of the flight crew.
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- Have your say: What is your reaction to the loss of the space shuttle Columbia? Your responses
- Backgrounder: What happened to Columbia
- Timeline: Space Accidents
- NASA updates on disaster
- Report on Columbia debris
- Family suffers double loss
- No indication terrorism involved: U.S. officials
- Six Americans, one Israeli on board
Please see also:
CTV News Live: U.S. President Bush's statement (3:19 min)
CTV News: NASA latest briefing, questions and answers, part one (21:46 min)
Lloyd Robertson with news of the space shuttle's disappearance (1:22 min)
Ivan Semeniuk of the Discovery Channel (3:37 min)
Former CSA astronaut Major Mike J. McKay (9:42 min)
CTV News: Lloyd Robertson talks with Mark Garneau (8:53 min)
Mr. Bush contacted the astronauts' families to express his sympathy and sorrow.
Captain Bill Readdy, associate administrator for space flight at NASA, told a news conference Saturday afternoon that it was still too early to speculate about the exact cause of the tragedy. NASA officials said they have no indication at this point that there was anything on the ground that caused the shuttle to break apart.
An internal investigation is underway. As well, an independent group has been charged with investigating the circumstances under which the space tragedy occurred.
"This is a truly difficult day for all of us," said Capt. Readdy, a former astronaut who himself has journeyed into space. "Today was a stark reminder this is a very risky frontier pushing back the boundaries of outer space."
NASA officials are focusing their immediate attention on the families of the seven astronauts, many of whom had been waiting at the Kennedy Space Center for the shuttle's landing, Capt. Readdy said.
"We all grieve for them," he said, adding that the families have told him that they "knew the crew was absolutely dedicated to the mission they were performing."
At Kennedy Space Center, the U.S. flag next to the countdown clock was lowered to half-staff.
Despite the more than 100 missions the space shuttle program has made, a journey into space is still risky, Capt. Readdy said.
"It is not routine," he said.
Ron Dittemore, the shuttle program manager at Mission Control, told a news briefing later Saturday afternoon that NASA had put a hold on future shuttle flights until the cause of the shuttle tragedy had been determined.
"We cannot yet say what caused [the] loss of Columbia," Mr. Dittemore said.
Mr. Dittemore said NASA lost contact with Columbia at 9 a.m. EST.
The first indication that there was a potential problem on the shuttle occurred minutes before 9 a.m. when there was a loss of temperature sensors, Mr. Dittemore said. Minutes later, several other problems followed, including a loss of tire indicators on the left side of the shuttle and indications of excessive heating.
He said investigators have started scouring data from the Mission Centre in an effort to determine the cause of the shuttle's destruction.
"We will be poring over that data" 24 hours a day for the foreseeable future, Mr. Dittemore said.
He confirmed that a piece of insulating foam from the shuttle's external fuel tank had flown off and may have hit the left wing during the shuttle's liftoff on Jan. 16.
At the time officials determined that there was no safety risk to the shuttle.
Mr. Dittemore said Saturday that it is to early to tell if there was any connection between that incident and the shuttle's disintegration. He warned people not to jump to any early conclusions and said the investigation should answer these questions.
He added that debris collected from the shuttle will help investigators put together the events that led to the tragedy.
NASA officials again reiterated to the public that they should not touch any debris from the shuttle, because it is most likely toxic, and have urged them to call local authorities. Debris is reported to have spread across Texas, Louisiana and apparently other states.
On the ground, search and rescue teams are scouring a large area from Dallas to East Texas, along the shuttle's flight path, searching for debris, Catherine Watson a NASA spokeswoman told CBC Newsworld. She didn't have immediate information on the debris being found.
Witnesses have said they have found small parts of the shuttle such as pipes.
"It looks like a very large debris field," Ms. Watson said.
Bush administration officials said there was no immediate indication of terrorism. A senior U.S. official, demanding 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.
At 9 a.m., when Mission Control lost all data and contact with the crew 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.
Residents of Nacogdoches, Tex., said they found bits of metal strewn across the city. Dentist Jeff Hancock said a metal bracket about 30 centimetres long crashed through his office roof.
"It's all over Nacogdoches," barber shop owner James Milford said. "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 southwestern United States and what should have been Columbia's flight path.
It was the 113th flight in the shuttle program's 22 years and the 28th flight for Columbia, NASA oldest shuttle.
In 42 years of U.S. 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 decent from orbit and is covered by about 20,000 thermal tiles to protect against temperatures as high as 3,000 degrees.
The shuttle was at about 63,000 metres over north-central Texas at 9 a.m., travelling about 20,000 kilometres an hour when Mission Control lost all contact and tracking data.
Gary Hunziker in Plano, Tex., said he saw the shuttle flying overhead. "I could see two bright objects flying off each side of it," he told The Associated Press. "I just assumed they were chase jets."
"The barn started shaking and we ran out and started looking around," said Benjamin Laster of Kemp, Tex. "I saw a puff of vapor and smoke and saw big chunk of material fall."
Security had been extraordinarily tight for Columbia's 16-day scientific research mission because of the presence of Colonel Ilan Ramon, the first Israeli astronaut.
Col. Ramon, 48, an officer 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 80-plus 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 Col. 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.
With reports from Associated Press