NASA Finds Cracks in Shuttle Tank |
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Written by spacetravel.org
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Sunday, 27 November 2005 16:00 |
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NASA has found nine hairline cracks in the foam of the external tank that is scheduled to fly on the next space shuttle mission.
The cracks were found in External Tank 120 (ET-120) in a manually applied section of foam called the protuberance air load (PAL) ramp. ET-120 was originally supposed to fly on Discovery's last shuttle mission. However, technicians discovered problems wih the fuel sensors when they added cryogenic hydrogen and oxygen during a fuelling test at Kennedy Space Center. NASA therefore switched tanks before the launch and shipped ET-120 back to an assembly facility near New Orleans, Louisiana for inspection.
Engineers are now slicing the foam to try to learn more about the cracks. Before the tank was sent to Kennedy Space Center, workers scanned the tank and were certain there were no cracks.. Managers fear the foam may have been damaged as the tank was being prepared for flight, so the possibility of worker error is being investigated.
NASA is trying to improve the manual application of spray-on foam for the PAL ramp before the next flight. NASA is also trying to develop a way for machines to apply the ramp, and running computer simulations to see if it is possible to remove the foam ramp entirely.
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