ASN Wikibase Occurrence # 244931
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Narrative:The shuttle's main fuel tank was covered in thermal insulation foam intended to prevent ice from forming when the tank is full of liquid hydrogen and oxygen. Such ice could damage the shuttle if shed during lift-off.
|Type:||Rockwell Space Shuttle Columbia|
|Fatalities:||Fatalities: 7 / Occupants: 7|
|Aircraft damage:|| Written off (damaged beyond repair)|
United States of America
|Departure airport:||LC39A, Cape Canaveral, Fl|
|Destination airport:||KTTS Titusville, FL|
|Confidence Rating:|| Information is only available from news, social media or unofficial sources|
Mission STS-107 was the 113th Space Shuttle launch. Planned to begin on January 11, 2001, the mission was delayed 18 times and eventually launched on January 16, 2003, following STS-113. The Accident Investigation Board determined these delays had nothing to do with the catastrophic failure.
At 81.7 seconds after launch from Kennedy Space Center's LC-39A, a suitcase-sized piece of foam broke off from the external tank (ET), striking 's left wing reinforced carbon-carbon (RCC) panels. As demonstrated by ground experiments conducted by the Accident Investigation Board, it is likely that this created a six-to-ten-inch-diameter (15 to 25 cm) hole, allowing hot gases to enter the wing when later reentered the atmosphere. At the time of the foam strike, the orbiter was at an altitude of about 65,600 feet (20.0 km; 12.42 mi), traveling at Mach 2.46 (1,872.57 mph; 3,013.61 km/h).
The left bipod foam ramp is an approximately three-foot-long (1 m) aerodynamic component made entirely of foam. The foam, not normally considered to be a structural material, is required to bear some aerodynamic loads. Because of these special requirements, the casting-in-place and curing of the ramps may be performed only by a senior technician. The bipod ramp (having left and right sides) was originally designed to reduce aerodynamic stresses around the bipod attachment points at the external tank, but it was proven unnecessary in the wake of the accident and was removed from the external tank design for tanks flown after STS-107 (another foam ramp along the liquid oxygen line was also later removed from the tank design to eliminate it as a foam debris source, after analysis and tests proved this change safe).
Close-up of the left bipod foam ramp that broke off and damaged the shuttle wing
Space Shuttle external tank foam block
Bipod ramp insulation had been observed falling off, in whole or in part, on four previous flights: STS-7 (1983), STS-32 (1990), STS-50 (1992), and most recently STS-112 (just two launches before STS-107). All affected shuttle missions completed successfully. NASA management referred to this phenomenon as "foam shedding". As with the O-ring erosion problems that ultimately doomed the Space Shuttle , NASA management became accustomed to these phenomena when no serious consequences resulted from these earlier episodes. This phenomenon was termed "normalization of deviance" by sociologist Diane Vaughan in her book on the launch decision process.
As it happened, STS-112 had been the first flight with the "ET cam", a video feed mounted on the ET for the purpose of giving greater insight to the foam shedding problem. During that launch a chunk of foam broke away from the ET bipod ramp and hit the SRB-ET attachment ring near the bottom of the left solid rocket booster (SRB) causing a dent 4 in (100 mm) wide and 3 in (76 mm) inches deep in it. After STS-112, NASA leaders analyzed the situation and decided to press ahead under the justification that "[t]he ET is safe to fly with no new concerns (and no added risk)" of further foam strikes.
Video taken during lift-off of STS-107 was routinely reviewed two hours later and revealed nothing unusual. The following day, higher-resolution film that had been processed overnight revealed the foam debris striking the left wing, potentially damaging the thermal protection on the Space Shuttle. At the time, the exact location where the foam struck the wing could not be determined due to the low resolution of the tracking camera footage.
Meanwhile, NASA's judgment about the risks was revisited. Linda Ham, chair of the Mission Management Team (MMT), said, "Rationale was lousy then and still is." Ham and Shuttle Program manager Ron Dittemore had both been present at the October 31, 2002, meeting where the decision to continue with launches was made.
Post-disaster analysis revealed that two previous shuttle launches (STS-52 and -62) also had bipod ramp foam loss that went undetected. In addition, protuberance air load (PAL) ramp foam had also shed pieces, and there were also spot losses from large-area foams.
||Updated [Aircraft type, Location, Phase, Nature, Departure airport, Destination airport]|
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