If we say what is the greatest human project in the 20th century, it must be the aerospace engineering. In this series of aerospace projects, the space shuttle is undoubtedly an important milestone in the world's aerospace history and the most important in the entire aerospace engineering. A shining star.
So far, only the United States and the Soviet Union have been able to build space shuttles that can travel to and from low-Earth orbit, and the United States is the only country that uses space shuttles to carry people into space. The space shuttle project is enough to demonstrate the United States’ leadership in the aerospace field. Sheep status. But behind such a glorious project, there is an unacceptable scandal.
In 2013, former NASA flight director Wayne Hall broke the news that NASA had predicted after the launch of the Columbia space shuttle that there would be a high chance that Columbia would disintegrate on its way back, but during the 17-day space flight During the mission, NASA did not take any remedial measures and concealed this fact. In other words, when the seven astronauts were performing the space mission, in the eyes of NASA senior officials, they had already been sentenced to death. So, , what happened at that time? Why not consider saving people?
Columbia accident
In 2001, Columbia was preparing to carry out a manned mission. However, the launch mission did not go smoothly. Due to a series of technical problems, the launch mission was postponed a total of 18 times until 2003. It was officially launched on January 16, 2011. However, after so many delays, problems still arose after the space shuttle was launched.
On the day after the launch, on the 17th, after the staff received the high-resolution film developed overnight, they discovered debris 81.9 seconds after launch. From the perspective of the photo taken, it seemed to be an external fuel tank. A large object in the left tripod area hit the underside of the space shuttle's left wing. On the 18th and 19th, engineers from Boeing Company analyzed that the two larger fragments were approximately 20x20x2 inches and 20x16x6 inches (about 50 cm). , hit the left wing at a speed of 822 km/h, but the more precise location and consequences of the impact cannot be accurately determined.
However, when almost all engineers believed that the impact might cause the space shuttle to burn through its wings when it returned, after reporting this issue to NASA's top management, the response they received was that they did not think it would cause serious consequences, and the severity of the impact was also repeated. was judged leniently.
In fact, in the early days of the space shuttle program, foam falling was considered a very dangerous accident, because these unexpected factors are likely to destroy the fragile thermal protection system. These thermal protection materials can even create a pit with a touch of your hand. However, Since Columbia's first flight in 1981, there have been accidents involving debris falling off and impacting. There is image evidence of foam falling off in 65 of the 79 space shuttle missions. More than 300 pieces of insulation tiles were replaced. , so much has fallen off. Despite the collision, Columbia still took off and landed smoothly, which led NASA executives to gradually misjudge that the foam shedding was not a big problem.
Regarding this issue, ground flight director Steve Stich also sent an email to captain Rick Hartsband on January 23. The general content is: The lower surface of the left wing It was damaged by the impact, but according to expert review, it will not cause damage to the insulation tiles. There is no need to worry about problems when returning. I hope reporters will not be surprised because they are ignorant when asking this question.
In addition, no matter how fiercely the engineers reported, they did not get any remedial measures from NASA. On February 1, Columbia began to return as planned.
When the space shuttle returned, everything seemed normal.At 8:55, about 11 minutes after Columbia entered the atmosphere, the temperature of the left wing reached about 1,600°C. At 8:58, when Columbia was traveling at an altitude of 63.9 kilometers and a speed of 9.5 Mach, it dropped a piece of thermal protection. Insulation tiles, the space shuttle was experiencing the most severe friction at this time, and the entire bottom of the fuselage was red; at 8:59, the ground found that the pressure readings of Columbia's two left main landing gear tires were missing, and asked the crew to confirm. At this time, it was suspected that the wing was burned through, and a large amount of high-temperature gas entered the interior of the wing.
The most terrifying thing about the rapid heating of the wing is not the failure of the internal components of the aircraft, but the excessive uneven heating that may directly cause the aircraft to disintegrate in the air. Sure enough, at 9:00, the Columbia disintegrated in the air, and the aircraft After the wreckage streaked across the sky like a meteor, there was nothing left in the sky.
During the investigation of the accident, it was found that what caused the disintegration of Columbia was the impact of the left wing, which caused the failure of some insulation tiles. The biggest "culprit" was the major defects in the installation process of surface foam materials. The cause of death of the astronaut blunt trauma and hypoxia.
Shocking revelations
In 2013, on the 10th anniversary of the Columbia crash, former NASA flight director Wayne Hare broke the news that after Columbia was damaged on the left wing, engineers had given a very clear conclusion on the damage assessment, that is On the way back, Columbia's left wing was likely to burn through due to the falling off of the heat insulation tiles, leading to a serious accident. However, after NASA executives learned of this conclusion, chose to inform all staff, including the astronauts. Conceal the seriousness of the problem and cover it up by saying "it will not cause a safety incident."
But later when mission commander Harpold held a meeting to discuss possible failures of the space shuttle, he had already anticipated the worst possible scenario:
"You all know that when the thermal insulation protective layer is damaged, we There is nothing we can do. So if an accident does occur, I think astronauts would rather be kept in the dark than to die without warning when returning, rather than knowing that the problem cannot be solved and staying in orbit. Is it better to wait for to run out of oxygen before dying? "
Regarding this revelation, NASA did not respond directly, nor did it stand up to refute the rumor. It seemed to be acquiescence to this revelation, but the original intention of the whistleblower Hal to disclose the secret was But I hope NASA executives will not make the same mistake as Columbia again.
The authenticity of this revelation can also be verified to some extent in the statement of a NASA official a few days after the Columbia crash. The official was quoted as saying that after Columbia took off, even if the problem was considered extremely serious, the chance of remediation was still limited. Zero:
First, it is impossible for astronauts to directly walk out of the Columbia cabin to perform repairs in space, and of course there are no repair tools.
Second, it is impossible for Columbia to dock on the International Space Station because it does not carry a "docking" tool.
This Columbia accident also made NASA finally make up its mind to abandon the space shuttle with an overly complex system and extremely expensive launch costs. In 2011, the space shuttle Atlantis completed its last mission and was announced to be retired. Since then, The United States mainly relies on Russian Soyuz spacecraft to transport astronauts to the International Space Station. Of course, today the United States can once again achieve the ability to conduct manned spaceflight in the United States through SpaceX's Falcon 9 rocket and Dragon spacecraft .
