IEEE
BERKSHIRE SECTION
High School STEM Research Challenge – 2021
The Challenger Disaster of 1986
Written for: The Institute of Electrical and Electronics Engineers, Inc. Berkshire Section STEM Research Contest
By Katherine Kerwood 41 Commonwealth Ave Pittsfield, MA 01201
March 8, 2021
Miss Hall’s School GRADE (12) Sue Lovell
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The Challenger Disaster of 1986
The launch of the Challenger in January of 1986 was the 25th mission of NASA’s Space
Shuttle Program and the tenth launch for the shuttle Challenger. It was carrying seven astronauts, including one teacher. The astronauts were Gregory Jarvis, Judith Resnik, Dick
Scobee, Ronald McNair, Mike Smith, Ellison Onizuka, and the teacher was Christa McAuliffe
(NASA). After a few delays, Challenger launched on January 28, 1986, at 11:38 am from the
Kennedy Space Center in Florida. Unfortunately, 73 seconds into the launch, Challenger
exploded and all seven astronauts’ lives were lost.
NASA’s Shuttle Program ran from 1981-201 (NASA Officials). NASA wanted to make space and space travel more accessible and reliable. Everything used for launch could be reused, except the external fuel tanks (NASA Officials); however, it took a lot of money and resources to repair these shuttles after every launch. The cost of the program was 113.7 billion dollars (NASA)
The shuttle itself was built to carry large loads into space. Challenger was carrying the second
Tracking and Data Relay Satellite and the Spartan Halley satellite (Challenger Disaster). This mission was supposed to have a teacher in space. Christa McAuliffe was chosen and she was going to do two lessons and other lectures during her time on the shuttle (Challenger Disaster).
Because of this, children all over the county were excited and watching this launch.
NASA’s Space Shuttle had four main parts. One was the orbiter that held the crew which detached from the rest of the shuttle and went into space. Behind that was the External Tank
2 which held liquid hydrogen and propellant gasses (NASA Officials). Above the External Tank, there was an intertank that connected the tanks holding liquid hydrogen and liquid oxygen
(NASA). On either side of the External tank, there were Solid Rocket Boosters. These boosters were the main power source during liftoff (NASA Officials). These boosters were too large to be assembled in one piece, so the pieces were stacked on top of each other at the launch site
(Berkes). Between the joints where the boosters were stacked, there were rubber O-rings that formed a seal so the gases wouldn’t leak out. Insulation putty was also used to make the seal more secure (Berkes). The image is a drawing of how the joints fit together and where the O-
rings sit (Rogers).
This launch had problems from the very beginning. It was originally scheduled for
January 22 but was ultimately delayed until the 27th. On the 27th everything was ready to launch but the fixture to close the hatch of the orbiter got stuck. It had to be sawed off and the launch was delayed until the next day, January 28th (NASA). On the night before the launch, temperatures dropped significantly. The morning of the launch, the temperature was 26°
Fahrenheit, well below the previous coldest launch temperature of 51° Fahrenheit (Rogers). Due
2 to the temperature, a couple of cameras on the launch pad stopped working. These cameras
“would have provided excellent viewage” said Dan Germany in the trials during the investigation into NASA (Key Sections of Testimony). Many engineers that worked at Thiokol, the company that made the Solid Rocket Boosters, had a bad feeling about the launch. They knew there was a chance that the O-rings that seal the joints of the boosters, could stiffen and shirk in the cold temperatures and might not form a complete seal. There was evidence of propellant leakage, at previous colder temperatures launches and tests (Berkes). It has been said that Morton Thiokol, the owner of the company, was persuaded to approve the launch, even though his engineers were voicing their concerns (Berkes). There was a teleconference in the early hours of January 28 between Thiokol and NASA officials. Thiokol shared their concerns about the performance of the O rings, but “... the risk … was not transmitted to the highest level of NASA” stated Sally Ride during the investigation trials (The Shuttle Inquiry). Some of the engineers that worked at Thiokol during this time still blame themselves for not pushing harder to delay the launch and feel guilty because of the lives lost (Berkes).
From early on in the launch, something appeared to be wrong. At about .68 seconds, smoke could be seen coming from the right Solid Rocket Booster (Rogers). The smoke was coming from the side of the booster that was closest to the External Tank. It appeared to be coming from the aft seal joint which was a joint near the bottom of the booster where different sections were stacked. Until about 2.5 seconds, puffs of smoke could be seen coming from this area, each one darker than the last. The darker color of the smoke indicated that the insulation putty and the rubber O-ring were being burned and eroded (Rogers) and indicated that the O- rings were not forming a complete seal. Thomas L Moser of NASA said, “At about 20 seconds is where the solid rocket booster begins to decrease its thrust in getting ready for maximum
2 dynamic pressure during ascent” (Key Testimony before Presidential Panel). From Missions
Control’s standpoint, everything seemed nominal. Maximum chamber pressure took place at about 60 seconds, and after that, the boosters started to increase thrust. As pressure increased, a plume of smoke and fire started to appear near the same joint as before. Mission Control then started to see a difference in pressure between the right and left Solid Rocket Boosters (Rogers).
The location of the failed seal caused the flames to hit and deflect off the External Tank.
At about 64 seconds, the plume changed shape and color indicating that there was a leak in the
External Tank and the liquid hydrogen was mixing with the fire (Rogers). The leaking of liquid hydrogen caused a thrust that drove the External tank into the intertank (NASA). The deflecting off the tank also caused the flames to hit the strut that attached the bottom of the booster to the
External Tank. This strut was being hit heavily with flames which caused it to break. The booster was no longer attached at the bottom, so it was free to move around. About 73 seconds into flight, the right Solid Rocket Booster swiveled around, and its nose crashed into the intertak and part of the oxygen tank. The fuel tanks collapsed and large amounts of liquid hydrogen and oxygen mixing resulted in a large fire. The shuttle broke into different parts due to the explosion; the tail with the main engine still burning, one wing of the orbiter, and the part that holds the crew (NASA). The solid rocket boosters survived and kept flying upward. It is believed that the crew also survived the explosion but became unconscious and died due to oxygen deficiency
(Challenger Disaster). Millions of people and the crew’s family and friends watched this space shuttle go up in flames. In March 1986, the crew module and part of the crew’s remains were found at the bottom of the ocean (Bearak).
After this disaster, a large investigation into NASA took place. The trial was trying to figure out what really happened and why the launch failed. They brought out some information
2 that probably would not have been public without the trials. For example, NASA had a list of waivers that were critical to a successful launch. One of the waivers “defined a condition under which the secondary seal may not form a seal” said Lawrence Mulloy of NASA (The Shuttle
Inquiry). The O-rings seal should have been a main priority because it was on this list and engineers were saying that they should not launch due to cold temperatures. NASA had a lot of pressure on them to keep a tight schedule, so they did not like the recommendations not to launch
(Berkes). Unfortunately, their decision to launch turned catastrophic.
This disaster started plans for redesigning the Solid Rocket Boosters to make them stronger and safer. A third O-ring was added to make the boosters more secure. Heating strips were placed along the O-rings so that they would never get below 75° F, no matter the outside temperature. They also made the O-rings out of a stronger and more durable material (Rogers).
The groove that the O-rings fit into also changed (NASA). The insulation inside the boosters was redesigned as well. They no longer used insulating putty, which was replaced by stronger, bondage insulation (Rogers). The pins that were placed along the joints to hold them together were lengthened. A port to perform leak checks was added, and the way the boosters connected
2 to the External Tank was redesigned (NASA). Image of redesign
(Rogers).
What happened to Challenger and its crew is truly a tragedy. One that could have been avoided if the NASA officials at the time made a different decision. I am planning to go into the field of aerospace engineering so something like this is interesting and important to me. I need to know what has happened in the past so I can make sure the same mistakes don’t happen again. I was able to expand my knowledge of spacecraft and what it takes to be successful in flight.
Challenger will always be remembered for what happened, but it is our job to make sure something like it doesn’t happen again.
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Works Cited
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