Space Shuttle Challenger disaster
||The English used in this article may not be easy for everybody to understand. (July 2012)|
The Space Shuttle Challenger Disaster occurred when Space Shuttle Challenger broke up 73 seconds after liftoff. All seven crew members were killed. The cause of the explosion was a O-ring failure in the right solid rocket booster. During the flight, hot gases escaped from the O-ring and made it break apart.
Problems Before Takeoff [change]
It was very cold on the morning of the Space shuttle's launch. The Challenger's engineers argued that the Challenger should not take off because the temperature was 31 °F (-1°C) and the O-Rings could not seal right if the temperature was under 53 °F (12°C). The NASA commanders did not agree and said that the backup O-ring would work. They were later proved wrong.
Another problem was that the temperature had gotten so low that icicles were hanging from some parts of the Challenger.
Vehicle breakup [change]
At 66 seconds after liftoff, the command was given to allow the engines to produce the highest thrust possible (Known as throttling up) as the shuttle started moving faster than the sound it was making. Michael J. Smith responded with "Roger that, go to throttle up." However, at 72 seconds after liftoff, the right booster pulled away from one of the parts attaching to the external tank. Right then, the Challenger suddenly went off its intended path, which may have been felt by the crew. At 73 seconds after liftoff, Smith said the last words picked up by the recorder designed to record all interactions in the crew area of the shuttle during flight: "Uh oh...". Smith may have been responding to the onboard computer telling him that the engines were moving quickly to compensate for the now loose booster in a useless attempt to get the shuttle back on the planned path, which showed that he knew about the problem about 3 hundredths of a second before the shuttle was torn apart.
Little is known of what happened in the minutes after the breakup. The crew cabin was still intact as it started falling. The official report into the disaster says that the crew survived the initial breakup and that at least three people were still alive. They were able to move switches which required a cover to be pulled off before they could be moved, probably when they tried to regain control of the craft. The crew cabin did not have any kind of parachute, and it hit the ocean after falling for 2 minutes and 45 seconds at roughly 207 mph (333 km/h), killing any crew that did survive the initial break up instantly with well over 200 times the force of normal gravity, which is like going from 0 to over 4,384 mph (7056 km/h) and then slowing back down to 0 all within a second.
Many people wanted to know why the Challenger exploded. President Ronald Reagan asked for a report about the disaster. It was called the Rogers Commission Report and it was written by a group of astronauts, scientists and engineers. They worked out what had happened and why the Challenger exploded. The report said that the people in charge at NASA did not listen to the engineers who said the O-rings were not safe; and that sometimes the people in charge thought that parts of the shuttle were well made when they were not. They also wrote that NASA sometimes did unsafe things because people would get angry if the shuttle launches were delayed.
There were no shuttle flights while the report was written. After the report was written, NASA had to be more careful in many different ways.