The Challenger was a
shuttle that was launched on
January 28, 1986 at 11:38am EST. It had a crew of seven people.
They had a planned objective of deploying satellites that were designed to track and observe
Halleys comet. There were other mission objectives, one which involved something called, "
Teacher in Space Project".
Sharon Christa McAuliffe was a public school
teacher, who was trained by
NASA, and accompanying the astronauts. It was part of a program NASA started to help educate children about
space exploration.
This was to be a historic shuttle launch, and schoolchildren around the nation sat in their classrooms and watched. Unfortunatly, what they saw was a tragedy. Not even 90 seconds after
liftoff, the shuttle exploded. All on board were killed.
Where were you when the Space Shuttle Challenger exploded? has become the This question is the "
Where were you when Kennedy was shot?", for
a generation.
This is a official report off of NASA's webpage about what exactly went wrong with the launch, and caused the explosion.
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.
Computer graphic analysis of film from pad 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.
Eight more distinctive puffs of increasingly blacker smoke were recorded between .836 and
2.500 seconds. The smoke appeared to puff upwards from the joint. While each smoke puff
was being left behind by the upward flight of the Shuttle, the next fresh puff could be seen
near the level of the joint. The multiple smoke puffs in this sequence occurred at about four
times per second, approximating the frequency of the structural load dynamics and resultant
joint flexing. As the Shuttle increased its upward velocity, it flew past the emerging and
expanding smoke puffs. The last smoke was seen above the field joint at 2.733 seconds.
The black color and dense composition of the smoke puffs suggest that the grease, joint
insulation and rubber O-rings in the joint seal were being burned and eroded by the hot
propellant gases.
At approximately 37 seconds, Challenger encountered the first of several high-altitude wind
shear conditions, which lasted until about 64 seconds. The wind shear created forces on the
vehicle with relatively large fluctuations. These were immediately sensed and countered by
the guidance, navigation and control system. The steering system (thrust vector control) of
the Solid Rocket Booster responded to all commands and wind shear effects. The wind
shear caused the steering system to be more active than on any previous flight.
Both the Shuttle main engines and the solid rockets operated at reduced thrust approaching
and passing through the area of maximum dynamic pressure of 720 pounds per square foot.
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.
As the flame plume increased in size, it was deflected rearward by the aerodynamic
slipstream and circumferentially by the protruding structure of the upper ring attaching the
booster to the External Tank. These deflections directed the flame plume onto the surface of
the External Tank. This sequence of flame spreading is confirmed by analysis of the
recovered wreckage. The growing flame also impinged on the strut attaching the Solid
Rocket Booster to the External Tank.
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. Telemetered changes in the hydrogen tank pressurization confirmed the leak. Within
45 milliseconds of the breach of the External Tank, a bright sustained glow developed on the
black-tiled underside of the Challenger between it and the External Tank.
Beginning at about 72 seconds, a series of events occurred extremely rapidly that terminated
the flight. Telemetered data indicate a wide variety of flight system actions that support the
visual evidence of the photos as the Shuttle struggled futilely against the forces that were
destroying it.
At about 72.20 seconds the lower strut linking the Solid Rocket Booster and the External
Tank was severed or pulled away from the weakened hydrogen tank permitting the right
Solid Rocket Booster to rotate around the upper attachment strut. This rotation is indicated
by divergent yaw and pitch rates between the left and right Solid Rocket Boosters.
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
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 2.8
million pounds, pushing the hydrogen tank upward into the intertank structure. At about the
same time, the rotating right Solid Rocket Booster impacted the intertank structure and the
lower part of the liquid oxygen tank. These structures failed at 73.137 seconds as evidenced
by the white vapors appearing in the intertank region.
Within milliseconds there was massive, almost explosive, burning of the hydrogen streaming
from the failed tank bottom and liquid oxygen breach in the area of the intertank.
At this point in its trajectory, while traveling at a Mach number of 1.92 at an altitude of
46,000 feet, the Challenger was totally enveloped in the explosive burn. The Challenger's
reaction control system ruptured and a hypergolic burn of its propellants occurred as it
exited the oxygen-hydrogen flames. The reddish brown colors of the hypergolic fuel burn are
visible on the edge of the main fireball. The Orbiter, under severe aerodynamic loads, broke
into several large sections which emerged from the fireball. Separate sections that can be
identified on film include the main engine/tail section with the engines still burning, one wing of
the Orbiter, and the forward fuselage trailing a mass of umbilical lines pulled loose from the
payload bay.
The Explosion 73 seconds after liftoff claimed crew and vehicle. Cause of explosion was
determined to be an O-ring failure in right SRB. Cold weather was a contributing factor.
Launch Weight: 268,829 lbs.