Bush honours shuttle astronauts

The Johnson Space Center has become a memorial

President George W Bush has paid tribute to each of the seven astronauts who died when the space shuttle Columbia broke up in the sky.

SHUTTLE CREW

Commander Rick Husband, US

Pilot William McCool, US

Michael Anderson, US

David Brown, US

Kalpana Chawla, US

Laurel Clark, US

Ilan Ramon, Israel

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Speaking at a memorial service in Houston, Texas, home of the Johnson Space Center, the president offered "the respect and gratitude" of the people of the United States to the five men and two women who perished.

"Today we remember not only one moment of the tragedy but seven lives of great purpose and achievement," he said in front of the 10,000 who had gathered for the service.

The space programme must nevertheless continue, he insisted, echoing the words of former President Ronald Regan's speech after the Challenger space shuttle was lost in 1986.

"This is not just an option we choose, it is a desire in the human heart. We are that part of creation which seeks to understand other creation," Mr Bush said in a deeply religious speech.

Mr Bush has sought a 3.1% increase in funding for the Nasa space agency for next year, to $15.5bn, including $3.9bn for the space shuttle programme itself.

Our nation shares in your sorrow and in your pride

President Bush

Click here for excerpts of speech

Amid suggestion that funding may have been a contributory factor in the disaster, White House spokesman Ari Fleischer said: "This administration is making no conclusions about whether the funding over the last decade or the increase in funding has anything to do with what took place on the Columbia."

Debris collection

Mr Bush's memorial speech came as the investigation continued into what caused the shuttle to break apart shortly before it was due to land back on Earth at the weekend.

Experts have widened their search for debris and human remains westward from Texas and Louisiana to California.

SHUTTLE BREAK-UP

Re-entered atmosphere at 12,500 mph (20,000 km/h)

Disintegrated 40 miles (65 kilometres) above the Earth

Debris scattered over Texas and Louisiana

Click here for a step-by-step guide to the disaster

A college professor in California has told Nasa that he saw tiles dropping from the shuttle as he watched its descent towards Florida through a telescope.

Officials plan to assemble the parts and reconstruct the shuttle to try to establish what happened in its final moments, but the task is monumental.

"Debris may not be located for weeks, for months, for years. Some of the debris may never be found," said Sheriff Thomas Kerss of Nacogdoches County, Texas, where much of the wreckage has been found.

Mixed messages

The BBC's Nick Miles in Houston meanwhile says that the US space agency is sending mixed messages about the possible role in the disaster of a piece of insulating foam that broke off and struck the shuttle during take-off, something which it says has happened before.

A Nasa report four days before the crash "made a determination that this was not a safety-of-flight-issue," Nasa's Michael Kostelnik told reporters on Monday.

First flight: 1981

Orbiting speed:
17,500 mph

Landing weight: 105 tonnes

Crew (for this mission):7

Columbia: Space pioneer

But at a separate briefing, shuttle programme manager Ron Dittemore said that while at the time, he thought this was a unanimous conclusion, he learned after the crash that there had been some dissent by analysts who "didn't come forward".

Nasa engineers, he said, were now focusing on the foam as the leading suspect in causing the problem that destroyed the Columbia.

The agency is considering the possibility that the impact from the foam - which was moving as fast as 2,400 km/h (1,500 mph) - damaged the shuttle's heat-resistant tiles near a wheel well, one of the most vulnerable parts of the vehicle.

US shuttles have been grounded indefinitely since the disaster struck at the weekend.

On Tuesday, an unmanned Russian cargo space ship arrived at the International Space Station to deliver fresh supplies and fuel to the three astronauts who have been cut off from their major supply line.