challenger disaster

challenger disaster

STS-51L Challenger Disaster & Investigation pt2-3 1986 NASA Space Shuttle

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video for embedding at http://scitech.quickfound.net/astro/space_shuttle_columbia_sts-107.html part 1: http://www.youtube.com/watch?v=amtjHRw42HY part 3: http://www.youtube.com/watch?v=UE1Xl5BtqbU from the Presidential Commission Report: "The final flight of the Challenger began at 11:38:00.010 a.m., Eastern Standard Time, January 28, 1986. The Flight of the Challenger The events that followed lift off were brief: Launch Time / Event - 6.6 sec. Space Shuttle engines ignition 0 sec. Solid Rocket Booster ignition + 7 sec. "Roll program." (Challenger) "Roger, roll, Challenger." (Houston) + 24 sec. Main engines throttled down to 94% + 42 sec. Main engines throttled down to 65% + 59 sec. Main engines throttled up to 104% + 65 sec."Challenger, go at throttle up." (Houston) "Roger. Go at throttle up." (Challenger) + 73 sec. Loss of signal from Challenger From lift off until the signal from the Shuttle was lost, no flight controller observed any indication of a problem... There were no alarms sounded in the cockpit. The crew apparently had no indication of a problem before the rapid break-up of the Space Shuttle system. The first evidence of an accident came from live video coverage. Radar then began to track multiple objects. The flight dynamics officer in Houston confirmed to the flight director that "RSO [range safety officer] reports vehicle exploded," and 30 seconds later he added that the range safety officer had sent the destruct signal to the Solid Rocket Boosters. During the period of the flight when the Solid Rocket Boosters are thrusting, there are no survivable abort options. There was nothing that either the crew or the ground controllers could have done to avert the catastrophe... Just after liftoff at .678 seconds into the flight, photographic data show a strong puff of gray smoke was spurting from the vicinity of the aft field joint on the right Solid Rocket Booster. The two pad 39B cameras that would have recorded the precise location of the puff were inoperative. Computer graphic analysis of film from other cameras indicated the initial smoke came from the 270 to 310-degree sector of the circumference of the aft field joint of the right Solid Rocket Booster. This area of the solid booster faces the External Tank. The vaporized material streaming from the joint indicated there was not complete sealing action within the joint... Main engines had been throttled up to 104 percent thrust and the Solid Rocket Boosters were increasing their thrust when the first flickering flame appeared on the right Solid Rocket Booster in the area of the aft field joint. This first very small flame was detected on image enhanced film at 58.788 seconds into the flight. It appeared to originate at about 305 degrees around the booster circumference at or near the aft field joint. One film frame later from the same camera, the flame was visible without image enhancement. It grew into a continuous, well-defined plume at 59.262 seconds. At about the same time (60 seconds), telemetry showed a pressure differential between the chamber pressures in the right and left boosters. The right booster chamber pressure was lower, confirming the growing leak in the area of the field joint... The first visual indication that swirling flame from the right Solid Rocket Booster breached the External Tank was at 64.660 seconds when there was an abrupt change in the shape and color of the plume. This indicated that it was mixing with leaking hydrogen from the External Tank... Beginning at about 72 seconds, a series of events occurred extremely rapidly that terminated [21] the flight... At 73.124 seconds, a circumferential white vapor pattern was observed blooming from the side of the External Tank bottom dome. This was the beginning of the structural failure of the hydrogen tank that culminated in the entire aft dome dropping away. This released massive amounts of liquid hydrogen from the tank and created a sudden forward thrust of about 2.~3 mil...