President George Bush was to attend a memorial service for the seven astronauts who perished aboard the Columbia, as Nasa’s probe of the tragedy focused on a piece of insulation that broke loose on takeoff.
After an exhaustive analysis of the debris that peeled off the shuttle’s external fuel tank and struck the left wing of the Columbia during takeoff on January 16 launch, engineers had concluded it did not pose a safety threat.
However, National Aeronautics and Space Administration officials on Monday admitted the engineers’ conclusion may have been wrong. Investigators now assume the foam’s impact was the trigger which caused the shuttle to disintegrate Saturday over the southern United States as it re-entered the Earth’s atmosphere, killing all its occupants.
”This debris is one of our primary areas of emphasis. We are completely redoing our analysis from scratch,” shuttle programme manager Ron Dittemore said.
”We’re making the assumption that the external tank was the root cause of the problem that lost Columbia.
”Even though that’s a drastic assumption that’s what I think we need to do.”
Columbia broke into pieces of flaming debris as it descended toward a scheduled 9:16 am (1416 GMT) landing at the Kennedy Space Centre in Florida.
Nasa analysts considered the possibility the impact from the piece of foam, which weighed slightly more than a kilogram, might damage one or more of the ceramic tiles which form the shuttle’s heat shield, Dittemore said.
However, they did not expect the damage to be severe enough to threaten the shuttle on re-entry, when temperatures reach 1 650 degrees Celsius, he said. Pieces of insulation had broken off on previous shuttle missions and impacted the spacecraft, but caused no significant damage, he said.
Dittemore said investigators remain baffled after two days of analyzing data as to why temperatures on Columbia’s left side spiked as much as 16 degrees Celsius in the minutes before contact was lost with the spacecraft about the time an unusual amount of drag caused the shuttle to roll to the left.
Prompted by what has already been learned, the agency has assembled a special team to search for debris west of the parts of Texas and Louisiana where most of Columbia’s remains have been found, he said.
Such debris could be significant because it could provide the vital missing link to the disaster, Dittemore said.
”We are extremely interested in any debris upstream of the
primary impact area,” he said.
Investigators also were talking to an amateur radio astronomer who said he had seen pieces of the shuttle break off as it crossed over California, where the first indications of a problem are now known to have surfaced, he said.
The Israeli daily Maariv on Monday published a picture of the US Columbia space shuttle, taken during a live video conference 11 days before the tragedy, apparently showing two cracks on its left wing.
An expert, however, dismissed the cracks as possibly a trick of the light, adding that such an anomaly would have been noticed by the Columbia’s crew and would have manifested itself as a structural failure very early on.
Meanwhile, hundreds of other investigators and volunteers hunting for the wreckage of Columbia fanned out over a 320-kilometre zone in eastern Texas and Louisiana in helicopters, on horseback or on foot in sticky mud.
Authorities have repeatedly warned the public not to touch any fragments, which may be covered with toxic propellants.
The grim search already has uncovered numerous remains from the astronauts including a torso, a leg, a skull and even a finger with a ring on it.
The remains are being tagged and transported by plane and truck to Barksdale Air Force Base in Louisiana, where a panel of outside experts appointed by Nasa met to look into the disaster.
The investigation of the disaster has revived longstanding concerns about safety in the US space program. Leaders in both the US Senate and House of Representatives said they will hold hearings on the issue.
Nasa administrator Sean O’Keefe met with Bush on Monday for 45 minutes to update him on the investigations and discuss ways to boost the agency’s morale.
Bush later paid tribute to the fallen astronauts, saying they would be ”remembered for their achievements, their heroism and their sense of wonder.”
Hundreds of friends, neighbours and total strangers of the fallen astronauts paid their last respects on Monday, laying flowers, flags and rocket-shaped balloons at an improvised shrine outside the Johnson Space Centre here.
In a statement, the astronauts’ families said they hoped the disaster would not threaten the US space programme, now on hold as Columbia’s loss is investigated.
”And although we grieve deeply … the bold exploration of space must go on,” according to the statement read by Nasa deputy administrator Bill Readdy.
The Bush administration on Monday proposed a 3,1% increase in Nasa’s budget to $15,5-billion for fiscal 2004.
It boosts funding for the space shuttle program by 24% to $3,9-billion, but includes no provision for a replacement of the Columbia. – Sapa-AFP