List the major space shuttle accidents in modern world history.

1.1986 65438+1October 28th is a cold day. In Cape Canaveral, Florida, the tragedy of the space shuttle Challenger is even more chilling than the weather.

On this morning, thousands of tourists gathered at the Kennedy Space Center, waiting for the spectacular sight of the Challenger taking off. 165438+ At 0: 38 in the morning, the challenger standing on the launcher ignited and flew directly into the sky, and the stands were full of joy. However, when the space shuttle flew for 73 seconds, there was a sudden muffled sound in the air, only to see Challenger explode into an orange fireball in an instant, and the debris dragged the flame and white smoke into the Atlantic Ocean. The explosion of Challenger shocked the whole world.

Seven astronauts were killed in the accident, including two female astronauts. Among them, mcauliffe, a female teacher who participated in space flight for the first time as a civilian, is particularly eye-catching. It was originally planned that she would give a live lecture to her students in space. Unfortunately, mcauliffe's ambition didn't come true, and she gave her precious life. According to the report of the presidential commission investigating the accident, the explosion was caused by the failure of an O-ring seal. This sealing ring is located between two low-level components of the solid rocket propulsion device on the right. The failed sealing ring caused the hot gas to ignite the fuel in the external fuel tank. O-ring will fail at low temperature. Although some engineers warned not to launch in cold weather on the eve of launch, the warning was ignored because the launch had been postponed five times.

Challenger is the second space shuttle at Kennedy Space Center. It was named after the British research ship Challenger, which sailed in the Atlantic and Pacific oceans. Some people may remember that Apollo 17 lunar module is also called Challenger. Just like its predecessors, the space shuttle Challenger has made great contributions to the space cause of mankind.

1In July, 982, the space shuttle Challenger became a reusable spacecraft with wings in the United States, and successfully completed nine space missions. 1986 65438+1On October 28th, the American space shuttle Challenger carried seven astronauts and made the first 10 flight of the space shuttle. In the ten missions of Challenger, * * * orbited 987 times and stayed in space for 69 days.

The crash of Challenger dealt a heavy blow to the American space industry, and the space shuttle stopped flying for the next three years. However, after summing up the lessons of the challenger, human exploration of space continues. Since the space shuttle resumed its flight, it has carried out 76 missions, including the establishment of the International Space Station. The astronauts of Challenger are pioneers of human space flight.

Seven astronauts took part in the space shuttle. They are: Captain Francis Scobie, 46 years old; Driver michael smith, 40 years old; Astronaut Judian resnick, 36 years old; Ronald mcnair, 35 years old; Ellison, Oni Tsuka, 39 years old; Gregory jervis, 4 1 year; Krista mcauliffe, a female teacher, is 37 years old.

2. The defect in the installation of foam material on the external fuel tank surface of the American space shuttle Columbia is the chief culprit of the whole accident. According to the investigation report released by the investigation committee of the space shuttle Columbia accident last year, a piece of foam falling off the surface of the external fuel tank hit the thermal protection system of the space shuttle, which was the main cause of the accident.

After the accident, NASA and the accident investigation Committee have not yet reached a final conclusion on the cause of the accident because the foam materials and fuel tanks at the time of the accident could not be quickly retrieved for inspection. At present, about 500 thousand pieces of Columbia's external fuel tank have been found and reassembled. Neil Ott, chief engineer of NASA in charge of the external fuel tank project of Columbia University, said that after many tests, NASA determined that defects in the installation process of foam materials were the main cause of the accident.

Ott said that there is no problem with the chemical composition of the foam itself, but the problem lies in the process of spreading the foam outside the fuel tank with a spray gun. The test shows that the current laying process will leave gaps between foam materials, in which liquid hydrogen can penetrate. After the space shuttle took off, hydrogen was heated and expanded, which eventually led to large foam falling off. The foam material that hit Columbia was the size of a suitcase and weighed about 0.75 kg. It was almost "torn off" by the whole piece and crashed into the thermal protection system at the leading edge of the left wing of the space shuttle at high speed, forming cracks. When the space shuttle re-enters the atmosphere, ultra-high temperature gas can enter Columbia from the crack, leading to the disintegration of the space shuttle.

Ott said that testing the fuel tank according to the new standard is the biggest obstacle that NASA is currently facing. The new standard requires that foam materials exceeding 0.5 ounces (14.17g) outside the fuel tank should not fall off. NASA is currently preparing to test 1 1 fuel tanks of all space shuttles, and it will cost $40 million to check each fuel tank.