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Post Info TOPIC: NASA near-misses


L

Posts: 131433
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Space Shuttle
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One of America's most experienced astronauts has denounced the space shuttle as a deathtrap and accused US space officials of stifling all concerns raised about its safety.

The revelation comes as America prepares to commemorate the 20th anniversary of the Challenger disaster. Seven astronauts were killed on 28 January 1986, when their shuttle exploded 73 seconds after take-off.
Veteran astronaut Mike Mullane's outburst therefore comes at a deeply embarrassing time for the Nasa. Apart from dealing with the Challenger anniversary, it is now struggling to save its remaining space shuttles so they can complete the international space station.
However, all three - Discovery, Atlantis and Endeavour - are still grounded because engineers have not yet fixed insulation problems that doomed Challenger's sister craft, Columbia, in 2003.

"It's the most dangerous manned spacecraft ever flown. It has no powered-flight escape system... Basically the bail-out system we have on the shuttle is the same bail-out system a B-17 bomber pilot had in World War II" - Mike Mullane, who took part on three shuttle missions before retiring in 1990.

It was this lack of ejector seats that ensured the deaths of Challenger's astronauts. Such a powered escape system could have blasted them from their stricken ship and saved them.

"That was the true tragedy of Challenger. Nothing was learnt. Only janitors and cafeteria workers at Nasa were blameless in the deaths of the Challenger seven. Columbia was a repeat of Challenger, where people had a known design problem and launched anyway." - Mike Mullane.

Mullane added that astronauts deserved some share of responsibility for not pursuing safety issues more doggedly.
It is estimated that it now costs Nasa $5bn a year to pay for the 16,000 engineers who maintain the fleet - even if none of them actually flies. As a result, the bill for designing, building and launching the shuttle has now topped $150 billion.
Engineers point out that the craft has been responsible for putting the Hubble space telescope and the International Space Station into orbit. However, each craft has thousands critical components. A failure of any of these will doom a craft. On Challenger, it was a seal on a solid rocket booster. On Columbia, it was piece of loose insulation foam.

"You walk in terrified of doing anything that might jeopardise your one chance to get to space. It's not like other jobs, where if you get frustrated you can go in to your boss and say "Shove it!" You can't do that at Nasa because there's no other place to go fly shuttles" - Mike Mullane.

The three remaining shuttles are supposed to retire in 2010 after completing construction work on the orbiting space station, which has been operating with a skeleton crew of two since the Columbia disaster.

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L

Posts: 131433
Date:
NASA near-misses
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Beyond the 1986 Challenger explosion and the February 2003 Columbia accident, NASA has had close calls on several missions. NASA identified 12 of the near-misses this spring to use as teaching tools for shuttle managers.

They were:

December 1983, Columbia: Dual shuttle computer failures could have led to loss of vehicle control during re-entry.
December 1983, Columbia: Rocket fuel fire during re-entry ended in explosions on Kennedy Space Centre’s shuttle runway.
August 1984, Discovery: Engine shutdown and launch pad abort led to a propellant leak and fire with six astronauts aboard a fully fuelled shuttle.
April 1985, Discovery: Brake failure and blown tire during a landing at KSC. Then-U.S. Sen. Jake Garn, R-Utah, was aboard.
January 1986, Columbia: Valve failure led to the accidental and undetected draining of liquid oxygen from the external tank. Had the countdown not been halted for an unrelated problem, astronauts would have been forced at make a risky emergency-landing attempt in Africa. Then-U.S. Rep. Bill Nelson, D-Melbourne, was aboard.
December 1988, Atlantis: Heat shield damaged after debris breaks free from solid rocket booster nose cap during launch.
January 1990, Columbia: Inadvertent thruster firing sent Columbia tumbling through space while the crew slept.
March 1992, Atlantis: Suspected space debris strike caused the same type of wing damage that doomed Columbia in 2003.
September 1993, Discovery: Simultaneous firing of primary and back-up explosive cords on a payload deployment device sent deadly shrapnel through the cargo bay.
September 1996, Atlantis: One of three auxiliary power units that control the wing flaps, brakes and steering during re-entry and landing failed shortly after Atlantis reached orbit. APU failures can lead to explosions or loss of control in flight.
June 1998, Discovery: Failure of a pressure sensor could have led to a main engine shutdown and perilous emergency-landing attempt in Europe or North Africa.
July 1999, Columbia: An electrical short crashed two main-engine computers five seconds after launch, leaving the crew one failure away from an emergency landing overseas. Veteran astronaut Eileen Collins was commander.


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