Ron Dittemore, Shuttle Programme Manager, NASA/JSC, relating to the incident on 1st February, reconstructed the final minutes of Shuttle Columbia’s flight before communication was lost in a news conference, stating that:
· At 13:52 GMT, three-left main gear brake line temperature sensors showed an unusual rise in the left wheel well area (Columbia approaching California coast).
· At 13:53, a fourth left brake line strut actuator temperature sensor showed a 30-40 degree Farenheit (17-22 degree Celsius) rise in temperature over a five-minute period (Columbia over California).
· At 13:55, a fifth left brake line main gear sensor showed a sharp rise in temperature.
· At 13:57, left wing temperature sensors failed “off-scale low”, meaning no further data was being received on the ground (Columbia over Arizona).
· And at 13:59, just before communication was lost with Columbia, there was evidence of drag on the aero surfaces of the left wing, causing two out of four yaw steering jets in that area of the Shuttle to fire for 1.5 seconds to counteract the increased drag. The vehicle was still under control, but the rates of change of trajectory parameters were greater than normally experienced.
Mr. Dittemore said more time will be needed to retrieve an additional 32 seconds of data acquired by ground computers after communication was lost with Columbia to see if it is useful to the inquiry.
Regarding a piece of foam insulation which fell off the External Tank some 80 seconds after launch, he said imagery analysis showed that the foam measured about 50 cm by 40cm by 15 cm and weighed about 1.2 kg.
The analyses were based not only on the STS-107 images but also on a similar incident that occurred on Shuttle Atlantis flight in October 2002 (STS-112), on which flight the crew had filmed the External Tank as it separated from the Orbiter during launch.
The conclusion at that time was that the debris did not represent a threat to the safety of the crew or the vehicle. The analyses will be repeated to determine whether this incident could have been a contributory cause to the eventual failure.
The collection and assembly of debris continues with especial emphasis on any items containing data or records. Each item is analysed to see if it can yield useful information.
In addition NASA are performing a series of analyses to try to predict the source of the problem. They will determine the amount of wing damage that would be necessary to lead to the un-symmetric drag values experienced during re-entry. They will analyse the amount of thermal protection loss that would have been necessary to lead to the progressive disintegration of Columbia that was experienced.