The morning of January 28, 1986 the orbiter Challenger was to embark on a historic journey. Challenger was to orbit the Earth and release the second Tracking and Data Relay Satellite (TDRS-B). It also carried the Spartan Halley spacecraft that was to be released and picked up two days later after observing Halley's comet during its closest approach to the sun.The launch took place at 11:38 EST on January 28, 1986. It appeared to be a normal launch until right after Challenger exited Max-Q, the time of the greatest aerodynamic pressure. Mission control told Commander Scobee, "Challenger, go with throttle up." Scobee replied,"Roger, go with throttle up" and seconds later the orbiter and its crew disintegrated in an explosion 73 seconds after lift-off at an altitude of 47,000 feet (14,240 meters). Debris from the orbiter crashed down into the Atlantic for more than an hour.
The cause of the accident was found within days and confirmed in a matter of a few weeks. The severe cold that the shuttle was exposed to reduced the resiliency of two rubber o-rings that sealed the join between the lower two segments of the right-hand solid rocket booster.
Normally when the Shuttles' three main engines ignite they press the whole vehicle forward and when the boosters were ignited the vehicle would swing back to center. On the morning of the accident an effect called joint rotation occurred, preventing the rings from resealing and opening a path for hot exhaust gas to escape from inside the booster. Puffs of black smoke appeared on the far side of the booster in a spot not visible with most cameras.
As Challenger rocketed toward outer space the leak expanded, 59 seconds into the flight, an eight foot (2.4 meter) flame emerged from the hole. The flame grew to 40 feet (12 meters) and slowly burnt through one of three struts that secured the boosters to the base of the large external tank carrying liquid hydrogen and liquid oxygen. At the same time, thrust in the booster lagged slightly, and the nozzle steering system tried to compensate. When the strut broke, the base of the booster went outward, moving the booster's nose through the top of the fuel tank and causing it to collapse and explode. On the ground this was seen as a brief flame licking from a hidden spot on the right side of the craft seconds before Challenger disappeared in a fireball. Even if the problem was discovered at lift-off, there would have been no hope for the crew to escape because the shuttle couldn't of survived high-speed separation from the tank until the last seconds of the booster's two-minute burn.
NASA launched a intense salvage operation to retrieve as much of the wreckage as possible. The task was complicated by the force of the explosion and the altitude it occurred at. The commission appointed to investigate the accident faulted NASA as a whole, and its Marshall Space Flight Center in Huntsville, Ala. and contractor Morton Thiokol Inc. in Ogden, Utah, in particular, for poor engineering and management. Marshall was responsible for the shuttle boosters, engines, and tank, while Morton Thiokol manufactured the boosters motors and assembled them at KSC.
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