The Challenger Disaster Jeff Naumick Matt Timer Justin Becker Brittany Ramans
Introduction • Following the 1960’s and 1970’s, the united states had established themselves superior in space exploration. The United States invested limitless money and resources into the program. • Apollo Program successes • International cooperation
Successes of the Apollo Program • Apollo missions 8 – 10 successfully delivered astronauts into lunar orbit • Mission 11 marked the first successful lunar landing • Missions 12, 14, 15, 16, and 17 also marked successful lunar landings • Apollo 13 ended in a lunar flyby as equipment malfunctions prohibited a landing
International Cooperation • At the conclusion of the Apollo space program, astronauts from the Soviet Union and the United States rendezvoused and docked in orbit • This marked unprecedented indication of cooperation in space
A Decrease in Interest • After the conclusion of the Apollo program and the death of president Kennedy, the country began to lose interest in space exploration. • Goals had been achieved but future benefits were viewed as somewhat unnecessary • Cutting funding and support of traditional space exploration was put into consideration.
Minimizing Costs • The innovative idea of building a reusable vehicle rose as a favorable solution • Cheaper, lighter materials were considered in order to minimize weight • Maximization of payload was the ultimate goal of achieving the ‘most with the least’
The Birth of the Space Shuttle The space shuttle was the culmination of the country’s a need for a reusable vehicle with orbital capabilities and reusability. It was designed to have a large payload and a lightweight body.
The Shuttle Stack Design • The shuttle stack is the combination of all the separate components that operate together in the launch of a crew into orbit The shuttle stack is composed of… - the external tank - the Orbiter - two solid rocket boosters
The External Tank • Mounted on the underside of the orbiter between the two solid rocket boosters • Houses the liquid fuel (liquid hydrogen and liquid oxygen) that react to fuel the main engines located on the rear of the orbiter • At launch, it is the heaviest component of the shuttle. It is jettisoned after the main engines shut down into the earth’s atmosphere and splashes down into the ocean.
The Solid Rocket Boosters (SRBs) • Provide a majority of the thrust required to put the shuttle stack into orbit (3,300,000 pounds of thrust per SRB at launch) • Jettisoned after reaching an altitude of nearly 28 miles and recovered and later reused • The weight of the SRB consists of 192,000 pounds composed in the exterior shell, nozzle and motor. Another 1,100,000 pounds are attributed to fuel weight.
The Orbiter • The orbiter is coated with thousands of thermal tiles that shield from heat during re-entry • It is designed to be a ‘shorts and t-shirt’ environment in space • Only portion of the shuttle stack that operates in orbit • Orbits with underside facing away from earth as the dark tiles shield from strong solar radiation
NASA’s Orbiter Fleet • Shuttle missions were carried out on one of five reusable orbiters • Columbia – The first launched orbiter (1981) which was lost in February of 2003 during re-entry • Discovery – First launched in 1984, and was responsible for the Hubble space telescope deployment • Atlantis – First launched in 1985 and was responsible for deployment of the Galileo which then made its way to orbit of Jupiter • Endeavour – The newest of NASA’s orbiters; first launched in 1992
The Challenger • NASA’s second orbiter put into service • Flew 9 successful flights prior to 1986 and spent a total of 65 days in orbit • Carried many vital spacelab components into orbit
Mission STS 51-L • Launch was slated for July 28th, 1985 • Mission objectives included… … deployment of a Tracking Data Relay Satellite … a free-flying module designed to observe Halley's comet … Conduct experiments (Fluid Dynamics and comet monitoring
The Crew • Francis R. Scobee (2), CommanderMichael J. Smith (1), PilotJudith A. Resnik (2), Mission Specialist 1Ellison S. Onizuka (2), Mission Specialist 2Ronald E. McNair (2), Mission Specialist 3Gregory B. Jarvis (1), Payload Specialist 1Sharon Christa McAuliffe (1), Payload Specialist 2
The Crew * Sharon Christa McAuliffe – First teacher in space
Pre – Launch Conditions • On the morning of the launch, the recorded temperature was 36 degrees (F), 15 degrees cooler than any previous launch • O-rings in the SRB’s were labeled as a potential problem prior to launch • Communication - between the outside contractor and NASA (ice on launch pad) - Between engineers and NASA • Pressure from the press
Countdown and Liftoff • At Launch Plus .678 seconds, a large puff of grayish black smoke was seen emerging from the aft field joint of the right Solid Rocket Booster (SRB). This indicated that the aft field joint was not completely sealed. • The puff of smoke achieved its highest level of visibility at Launch Plus 1.9 seconds. The puff of smoke was pinpointed to have emerged from between the 270 degree and 310 degree circumference points of the aft field joint, directly between the right SRB and the External Tank (ET). By Launch Plus 3.375 seconds, the smoke was no longer visible. • At Launch Plus 58.788 seconds, a burn-through plume was seen emerging from the aft field joint of the right SRB. At roughly this same time, telemetry data indicated that the pressure of the right SRB had become lower than that of the left SRB. • At Launch Plus 62 seconds, telemetry data indicated that the Orbiter's automated guidance control system had begun responding to the dynamic forces caused by the burn-through plume. At Launch Plus 64.66 seconds, the burn-through plume penetrated the ET, which began to lose pressure as a result.
Countdown and Liftoff • At Launch Plus 64.705 seconds, a bright glow formed between the right SRB and the ET. At Launch Plus 66.8 seconds, ET pressure dropped dramatically. At Launch Plus 72.2 seconds, the lower strut attaching the right SRB to the ET was torn loose, causing the right SRB to move erratically. • By Launch Plus 72.6 seconds, liquid hydrogen pressure could not be maintained. At Launch Plus 73 seconds, both liquid hydrogen and liquid oxygen pressure within the ET dropped to near zero. • At Launch Plus 73.124 seconds, the liquid hydrogen tank within the ET suffered a structural failure. This was followed by a structural failure of the liquid oxygen tank within the ET at Launch Plus 73.137 seconds. Both of these structural failures caused fuel and vapor to stream along the exterior of the ET.
Countdown and Liftoff • At Launch Plus 73.191 seconds, a bright flash was seen between the ET and the Orbiter as leaking fuels and gases began to mix and ignite. This was followed by total vehicle break-up at Launch Plus 73.213 seconds. • Telemetry data indicated that the Orbiter's three main engines shut down automatically at Launch Plus 73.6 seconds. The last telemetry signal was received from the Orbiter at Launch Plus 73.618 seconds. • The right SRB and left SRB continued to fly after the total vehicle had broken up. Video analysis confirmed that the aft field joint was missing from the right SRB as it continued to fly. Both SRB's were destroyed by the Range Safety Officer at Launch Plus 110 seconds.
Engineering Flaws • O – rings: Cold temperature caused inconsistency in material which lead to inability to withstand stress. Holes formed in O-rings which led to erosion by hot leaking gases • Structural strength: Use of lighter, weaker materials to save money and maximize available payload weight • Wing (pressure) seals: Contractors made no effort to improve design. NASA also tolerated the poor design, only striving to meet the bare minimum * NASA had excess money in the budget that would have solved these problems, but did nothing
Prevention • Develop better communication between NASA and the contracted engineers and private contractors • Recognition of structural problems and immediate research and correction of the problems - O-rings - Wing seal design • Use of stronger structural materials • Better recognition of launch day conditions (Temperature)
Changes in the Program • Adjustments to the solid fuel boosters – Insulation and O – ring configuration • Safety measures for the crew • Relaxed launch schedule • Less adherence to private contractor payload delivery • More strict pre-launch checks and tests
Technical Terms • Shuttle Stack – The combination of orbiter, external tank, and two boosters that is needed to send the orbiter to earth’s orbit. The entire stack remains intact for only a brief portion of every mission. • External Tank – The large tank on the underside of the shuttle in the shuttle stack. It houses the liquid fuel needed to get the shuttle into orbit. In years past, it would be painted white, but to minimize costs, NASA has discontinued that practice. • Boosters – The external boosters that are responsible for delivering the thrust necessary to send the shuttle stack into orbit. They are deployed once their fuel has been used and drift back to earth, where they are recovered. • Orbiter – The portion of the shuttle stack often referred to as the shuttle. It houses the mission crew and is responsible for in flight operations and commands. NASA has produced 5 orbiters: Discovery, Challenger, Columbia, Endeavour, and Atlantis. • O – Rings – The polymer sealant responsible for preventing hot gas leakage during launch of a shuttle. They are responsible for conjoining larger metallic seconds of the boosters. • Composite – A combination of light weight materials, in this case, used to minimize weight in the shuttle. Though often very strong, in many cases, they are not as strong as their raw components. • Oxidizer – An agent that aids in the combustion of a fuel through oxidization. • Wing Seal – Stronger composite bond that is designed to withstand the extreme pressures of shuttle liftoff.
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