Solid Rocket Booster And The External Tank example essay topic

The Tragic Challenger Explosion The Tragic Challenger Explosion Space Travel. It is a sense of national pride for many Americans. If you ask anyone who was alive at the time, they could probably tell you exactly where they were when they heard that Neil Armstrong was the first person to walk on the Moon. But all of the success in our space programs is overshadowed by tragedy. On January 28, 1986, one of the worst disasters in our space program's history occurred. Many people were watching at the moment because it was the highly televised space mission where, for the first time, a civilian was a member of the crew that was to be shot into space.

This civilian was the winner of the 'Teacher in Space' contest, Christa McAuliffe. The disaster: the explosion of the Space Shuttle Challenger. (Compton's 1) Many people thought that disaster couldn't strike because a civilian was on board. But as the whole nation found out, nobody is immortal.

By examining this further, we will look at the lives of the seven who died in this dumbfounding calamity, take a look at exactly what went wrong during this fateful mission, and the outcome from this sorrowful occurrence. First, who exactly were those astronauts that died on the Challenger? Sharon Christa Corrigan McAuliffe, born in 1948, was the famous winner of the teacher-in-space program, was a high school teacher at Concord, N.H., a wife, and a mother of two children. She touched the lives of all those she knew and taught. As a school official in Concord said after her death, 'To us, she seemed average. But she turned out to be remarkable.

She handled success so beautifully. ' She also wanted everyone to learn more, including herself. Demonstrating her aspirations after entering the space program, she is quoted saying, 'What are we doing here? We " re reaching for the stars.

' Also, after reflecting on her position, she said in August 1995, 'I touch the future, I teach (Gray 32). ' Francis R. (Dick) Scobee, born in 1948, was a tremendous enthusiast for aviation and the space program. At 18 years old, he enlisted in the Air Force. While working as a mechanic in the service, he put himself through night school, eventually earning a degree in aerospace engineering that helped him become an officer and a pilot. He loved flying. Scobee once observed, : You know, it's areal crime to be paid for a job that I have so much fun doing.

' On one of his space missions, he carried a banner made for him by students at Auburn High, his old high school. It read 'TROJANS FLY HIGH WITH SCOBEE. ' School officials announced after the tragic explosion that the banner would be put on display to remind others at Auburn High that other seemingly ordinary students can too fly high. (Gray 33) Judith Resnik, born 1949, had a Ph. D. in electrical engineering. She was very ambitious and loved everything. She once said, 'I want to do everything there is to be done.

' Being chosen for the space program gave her the opportunity to meet a few self-described personal goals: 'To learn a lot about quite a number of different technologies; to be able to use them somehow, to do something that required a concerted team effort and, finally, a great individual effort (Gray 33). ' She had said once, when asked, about the dangers of the space program, 'I think something is only dangerous if you are not prepared for it or if you don't have control over it or if you can't think through how to get yourself out of a problem. ' For Resnik, danger was simply another unknown to be mastered. Ronald McNair, born in 1950, was the second black man in space. He was truly remarkable growing up in his segregated South Carolina school.

He was remembered by those he knew as 'one who was always looking to the clouds. ' Jesse Jackson, one of his collage classmate's at N.C. Agricultural and Technical State University said McNair saw participation in the space program as 'the highest way he could contribute to the system that gave him so much. ' McNair did think much of the space program. He once said, 'The true courage of space flight comes from enduring... persevering and believing in oneself (page 34). ' Michael Smith, born in 1945, always had his head in the clouds. At the age of 16, he soloed in a single-engine Aeron ca.

After the U.S. put its first astronaut into space in 1961, Smith decided that was where he wanted to be. His older brother said, 'In high school he paid a lot of attention to academics because he knew that was the best way to get in. ' Heal so thought much of the space program. He once said, 'Everybody looks at flying the shuttle as something dangerous. But it's not.

It's a good program, and something the country should be proud of (Gray 34). ' Ellison Onizuka, born in 1946, became an instant hero to both the Hawaiians and the Japanese Americans because he was the first member of either group to fly in space. He was one who was always fascinated by the vastness of outer space and spend a lot of time studying it. When he was young, he spent much of his time examining the universe through a telescope at Honolulu's Bishop Museum. He also said before the Challenger launch, 'I'll be looking at Halley's comet.

They tell me I'll have on of the best views around (Gray 35). ' His family always looked favorably upon his achievement. After the tragedy, his mother remembered that 'Ellison always had it in his mind to become an astronaut, but was too embarrassed to tell anyone. When he was growing up, there were no Asian astronauts, no black astronauts, just white ones (Gray 35).

' Ellison will be forever remembered as being the first Japanese American in space. Finally, the last member of the seven person crew, Gregory Jarvis, born in 1944. Gregory was very dedicated to the space program. Despite being bumped off two previous flights, he finally got his chance. Unfortunately, his only flight was that of the Challenger.

Itis very saddening to see seven bright lives vanish in a ball of fire, but it is said that the explosion was so rapid that the crew did not realize their coming fate. (Gray 35) Perhaps we can all take comfort in the fact that their last vision was that of the stars. Now, many people haven't heard exactly what went wrong to cause such an explosion. (Dumoulin, 1-2) The Challenger finally launched after five days of delays.

On January 28, 1986, the morning of the launch, there was ice at Kennedy Space Center. After an inspection crew gave the go-ahead, the launch was underway. Just after liftoff at. 678 seconds intothe 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 circumferential ly 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 futility 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 inter tank structure. At about the same time, the rotating right solid rocket booster impacted the inter tank 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 inter tank 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 inter tank.

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 solid rocket booster. Cold weather was a contributing factor. Finally, what was the outcome of this terrible disaster? (Compton's, page 1) The shuttle program was suspended until the exact cause could be found. It wasn't until September 1988 when the next shuttle launch happened.

After many hours of investigating and finding out what exactly caused the disaster, many changes were made to the structural designs of the space shuttle. Also, they don't allow launches when the temperature is that low. Also, the explosion delayed the now famous Hubble Telescope program (Church 38). We have seen the tremendous photographs the Telescope has sent to Earth, it's a shame they couldn't have been received sooner.

From a media standpoint, this disaster really changed the way television was used to report major disasters. It may seem fairly common when Special Reports interrupt normal programming, but in 1986, it was pretty unusual. In fact, ABC switchboards alone fielded more than 1,200 complaints from people who wanted to watch soap operas rather than an all-day report about the Challenger and the late breaking news related to it (Zoglin 42). Television definitely had a tremendous impact on reporting this story. ABC Anchorman Peter Jennings said,' We all shared in this experience in an instantaneous way because of television. I can't recall any time or crisis in history when television has had such an impact.

(Zoglin 42) ' The disaster even affected President Reagan's State of the Union address. When asked about the State of the Union speech, Reagan replied,' There could be no speech without mentioning this, but you can't stop governing the nation because of a tragedy of this kind (Magnuson 29). ' In conclusion, its such a sad tragedy that this negligence led to such a disaster. If we learn from our mistakes, then hopefully, this sort of disaster won't happen again.

Bibliography

Space Shuttle Missions: Challenger. ' Compton's Encyclopedia of American History on CD-ROM. Compton's New Media, Inc., 1994.
Morrow, Lance. 'A Nation Mourns. ' Time 10 February 1986: 23.
Magnuson, Ed. 'A Nation Mourns. ' Time 10 February 1986: 24-31.
Gray, Paul. 'Seven Who Flew for All of Us. ' Time 10 February 1986: 32-35.
Friedrich, Otto. 'Looking for What Went Wrong. ' Time 10 February 1986: 36-37.
Church, George J. 'Putting the Future on Hold. ' Time 10 February 1986: 38-41.
Zoglin, Richard. 'Covering the Awful Unexpected. ' Time 10 February 1986: 42-45.
Murphy, Jamie. 'It Was Not the First Time. ' Time 10 February 1986: 45.
Dumoulin, Jim. '51-L' [Online] Available web October 5, 1996.