Seven die in shuttle disaster

It is the worst space accident for the US since 1986

The US space shuttle Columbia has disintegrated after re-entering the Earth's atmosphere, killing all seven crew on board.

The space agency Nasa lost contact with the craft about 15 minutes before it was due to land at the Kennedy Space Center in Florida.

In a televised statement, a sombre President Bush paid tribute to the six American and one Israeli astronaut.

	:	Shuttle disaster
How the disaster happened

"These astronauts knew the dangers and they faced them willingly," he said.

"Because of their courage and daring and idealism, we will miss them all the more."

He said the thoughts of all Americans were with the dead astronauts' families, but he pledged that space exploration would continue.

The cause in which they died will continue

President Bush

Full text of speech

Shuttle programme manager Ron Dittemore told a news conference Nasa could not yet say what caused the break-up of Columbia.

Thorough investigations were beginning to find out what happened during the last minutes of the flight, when some of the shuttle's sensors began to malfunction.

"Right now there is certainly a hold on future flights until we get ourselves established and understand the root cause of this disaster," he said.

Click here to watch reports on the disaster

Experts have suggested that the cause of the break-up was probably mechanical or structural.

Heightened security had surrounded Columbia's latest mission because of the presence of Colonel Ilan Ramon, the first Israeli in space.

There was a shocked reaction in Israel to the disaster. "The people of Israel bow their heads today in view of this great tragedy," said a statement from Prime Minister Ariel Sharon's office.

Cargo launch

Russian president Vladimir Putin said his country's co-operation in space exploration made the accident even more tragic for Russians. But the scheduled launch of a Russian cargo vessel to serve the International Space Station (ISS) will go ahead on Sunday.

First flight: 1981

Orbiting speed:
17,500 mph

Landing mass: 105 tonnes

Crew (for this mission):7

Columbia: Space pioneer

Hundreds of US state troopers, police and rescue workers are searching large areas in eastern Texas for debris from the shuttle.

Columbia, which had been due to land at 0916 EST (1416 GMT) was returning from a 16-day mission orbiting the Earth and had just begun its re-entry procedure when contact was lost at about 0900 EST.

Nasa said the shuttle was about 200,000 feet up and travelling at 12,500 mph (20,000 km/h) at the time.

Television pictures showed a vapour trail from the craft as it flew over Dallas.

It then appeared to disintegrate into several separate vapour trails, and witnesses in the area said they heard "big bangs".

Texas public safety department spokesman Clive Kennelly said there were more than 2,000 debris fields, scattered from the small town of Nacogdoches about 170 miles (290 km) south-east of Dallas, to the Louisiana border.

I could see two bright objects flying off each side of it

Eyewitness in US

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Nasa has warned that any debris found should be avoided as it could be hazardous, and that people should report such finds to the authorities.

Pieces of debris have been reported in fields and on roads, and one Nacogdoches resident, Jeff Hancock, said a metal bracket about a foot (30 centimetres) long crashed through his office roof, the Associated Press news agency reported.

Support for families

Never before in 42 years of human spaceflight, has Nasa lost a space crew during landing.

SHUTTLE CREW

Commander Rick Husband, US

Pilot William McCool, US

Kalpana Chawla, US

Laurel Clark, US

Ilan Ramon, Israel

David Brown, US

Michael Anderson, US

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In 1986, the space shuttle Challenger exploded shortly after lift-off with the loss of all seven crew on board.

Columbia, which first flew in 1981, was the oldest craft in Nasa's space shuttle programme.

Nasa has assigned a former astronaut to the family of each crew-member to provide support.

"They have been with each family since the mission began and are trying to help them cope with this terrible tragedy," a Nasa official told the BBC.

Repercussions

The BBC's Leo Enright says that one immediate concern is the fate of the ISS.

Indian-born Kalpana Chawla was on board

Three crewmen are currently living and working aboard the station, and the space shuttle is a vital link providing them with supplies.

Europe, Japan, Canada and Russia have all invested heavily in this enterprise, which had come to rely more and more on the Americans' space shuttle fleet.

Our correspondent says all future plans must now be reviewed, and experts must decide whether the station can remain operational or whether it should be mothballed.