Space Shuttle Challenger

[RWC130 594]

DAY OF REMEMBRANCE

JANUARY 28, 1986

SPACE SHUTTLE CHALLENGER (STS-51-L)

Francis R. Scobee

Michael J. Smith

Judith A. Resnik

Ellison S. Onizuka

Ronald E. McNair

Gregory B. Jarvis

Christa McAuliffe

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.

[Guest]

I did a report on Christa McAuliffe, the first teacher turned astronaut, the whole story was very interesting. Weird thing is, my mom was in the hospital waiting for me to be born....turns out i was 3 days late.

[RWC130 594]

I was in 5th Grade Art Class. (I feel old now) The art teacher put the TV on and we watched it happen live. Really sad...

I will never forget the last words of the crew, images and audio played on TV

over and over and over.

Mission Control: "Challenger, Go with throttle up"

Challenger: "Roger, Go with throttle up"

[calhobs 110]

I was leaving the Pan AM parking lot at JFK going to work when we heard about it. sad sad sad day.

[Guest E53LT]

I hope that with all that's going on in the world right now, the news will take time to remember those brave souls.

[ryefd192 2]

In the fall, Auburn put on a play called "Defying Gravity" that was about the challenger. It was very moving.

[llm60 0]

I remember that day like it was yesterday I was in 4th grade and our teacher let us watch it on TV During class, That was a very sad day I will never forget

[fitzjr11 17]

Was in 4th grade, my music teacher had applied for the position. Found out that her family lived near Christa McAuliffe, and met her did an interview and got an autographed pict, which was copied and given to the entire elementary school. I remember watching it in school as well.

[Guest Moose131]

"The crew of the space shuttle Challenger honored us by the manner in which they lived their lives. We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved good-bye and 'slipped the surly bonds of earth' to 'touch the face of God.'"

-Ronald Reagan

[Guest alsfirefighter]

I was in 6th grade and can remember my teacher coming in crying and one of my classmates was in the library when it happened and told us. Didn't get to see the images until I got home. Still can't believe they let that launch go.

[firecapt32 282]

OK OK I wasent in the 4 th grade or the 6th grade but still rememebr it. There are a lot of times that stick out in a persons memory. this horrible incident is certinly one of them. It will be a lasting memory in our lives, and the world is a safer place because these men and women gave their lives for us.

I know ALS you want to know where I was right??

Working days in the fire station I was in my 14th year!!! I remember where I was when JFK was shot, Martin Luther King, RFK, John Lennon.

When Neil Armstrong steped on the moon.