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NASA weighed retiring Columbia in 2001
By Richard Stenger
(CNN) -- The space shuttle Columbia, lost with its seven-person crew in a catastrophic re-entry accident on Saturday, was considered for retirement in 2001. The oldest orbiter in the fleet, it had experienced engineering problems before during a long career that begin with the first shuttle mission more than 20 years ago. Yet none of the previous glitches on Columbia, which underwent a $90 million, 17-month overhaul that began in September 1999, were thought to have contributed to the fatal mishap. The 90-ton shuttle, heavier than other spacecraft in the fleet, was the only one not outfitted to dock with the international space station. NASA had considered mothballing it in 2001 because of budget constraints, but decided to keep it in service, in part to ensure flying several scheduled missions. They included the one known as STS-107, which, after years of delays, went into space in mid-January for a rare mission devoted solely to science. The $2 billion craft has been part of numerous NASA milestones since becoming the first shuttle to go into orbit in 1981. In 1999, it deployed the powerful Chandra X-ray space telescope, with the first female commander at the helm, Eileen Collins. But that mission began with major problems. The shuttle had leaked thousands of pounds of fuel during liftoff, leaving it in a lopsided but functional orbit. And seconds after launch, a short circuit knocked out computers that controlled two of three shuttle engines. A backup computer system kicked in, narrowly avoiding the need for an emergency landing. NASA grounded the fleet for months to inspect and repair exposed wiring on the four orbiters. Each has more than 100 miles of electrical wiring. On the most recent, fatal flight, NASA technicians reviewing video noticed that a piece of insulation fell off the the external fuel tank and seemed to strike the shuttle during its eight-minute race to orbit, possibly knocking off heat-resistant tiles, which protect the shuttle from the intense temperatures of atmospheric re-entry.
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