THE US: The Columbia space shuttle disaster was probably caused by a seal that broke between protective tiles on the left wing, according to preliminary results from the official inquiry announced yesterday.
"We now know enough . . . to the point where we should now focus our effort," said retired admiral Hal Gehman, who heads the Columbia Accident Investigation Board.
Mr Gehman, speaking at a press conference broadcast from the Johnson Space Centre in Houston, Texas, described the preliminary findings as "a working hypothesis" that was reached in the previous 10 days.
Columbia disintegrated on re-entering Earth's atmosphere on February 1st, killing all seven astronauts on board, just 16 minutes prior to its scheduled touchdown in Florida.
The seal was probably damaged just 81 seconds after the Columbia blasted off on January 16th, when the shuttle's left wing was hit by a piece of insulating foam that broke off from one of the shuttle's external fuel tanks.
Superheated gases seeped under, entered the shuttle's heat-resistant external tiles upon re-entry and penetrated the spacecraft's cabin, resulting in disintegration.
Two days after the launch incident, as the Columbia and its seven astronauts were orbiting the earth, a North American Aerospace Defence system (NORAD) military radar detected a small object being detached from the shuttle.
The object remained close to the shuttle until it returned into the earth's atmosphere, Mr Gehman said.
Tests carried out to identify the object showed it corresponded to "a T-seal between the RCC (reinforced carbon-carbon) tiles on the left wing lead edge" used to bind together the heat-resistant reinforced carbon tiles that protect the leading edge of the wings from re-entry heat, Mr Gehman said.
On Sunday a US-Russian crew stranded in space by the shuttle tragedy were found alive and well after losing radio contact on re-entry and landing almost 500 km off target in the steppes of Kazakhstan.
The Americans, Mr Ken Bowersox and Mr Donald Pettit, and Russia's Mr Nikolai Budarin had already had to extend a three-month stay on International Space Station to almost six after the loss of the Columbia shuttle. They had to wait over two hours to be located by anxious rescuers scouring the Central Asian steppes in planes and helicopters. - (AFP, Reuters)