Regarding "zeroing", we will explain it to you with a lively article. After reading it, you will understand!
"Zeroing" is an unfamiliar word for many people, and there are many untold stories behind it. "Simply put, start from scratch." Even some people in the space system think so. But is that all?
What is the word that astronauts fear the most? As soon as I hear this word, my hair is upside down and my hands and feet are cold.
Just three words: No! ask! title!
Aerospace work is extremely complex, and blurting out "no problem" is the biggest problem. Behind this means that there may be cognitive blind spots caused by path dependence.
Take the Shenzhou spacecraft: the spacecraft weighs 8 tons, the total length of 8m, it is composed of 13 subsystems, equipped with 52 engines with different thrusts, the total length of the cables on the spaceship is more than 30km, a total of more than 600 equipment, more than 100,000 components. How many units are involved in the development? Almost 1,000! And how many parts does the shuttle have? 2.5 million!
In the face of such a complex system, who dares to casually say that there is no problem? No problem, it does not mean that it is really done, but it means that the person may be in a situation of "not knowing that he does not know", which is the most dangerous. In other words, it's not that there's really no problem, it's that you can't see the problem.
In the early stages of manned spaceflight, the most tragic accident was the Apollo 1 spacecraft. Because of the fire, three astronauts were burned alive in ground simulation tests. This is not a man-made accident, not a tragedy caused by the carelessness of any engineer, but mainly a lack of awareness of the potential threat of pure oxygen schemes.
There is no oxygen in space, so the spacecraft needs to be filled with oxygen, and the Apollo spacecraft at that time used pure oxygen at 1/3 of the atmospheric pressure, which was a very natural and reasonable choice. But beyond the engineer's cognition is the pure oxygen environment, many things that are not flammable have become flammable, and some plastic products that are refractory materials in normal air have become flammable items in pure oxygen, which is the cognitive blind spot caused by path dependence. There are also problems with the hatch design, which can never be opened within the 90s. After the fire, negative pressure formed inside the spacecraft, and it could not be opened from the outside for a short time. This led to the fire killing three astronauts in just thirty seconds.
Thirty seconds, three lives.
Therefore, in order to break through the cognitive boundaries, space exploration must be able to cope with various variables, which leads to astronauts can only provide everything they need with a complex system; but the system itself is too complex, no matter how carefully polished each component, you can't guarantee that after assembling them together, you can still achieve the desired design goals. Therefore, there is no way to predict in advance where the risk will occur, which is "Schrödinger's risk".
So how do you expose the invisible problem? A simple summary is to do two things well: the design phase, through simulation to eliminate possible problems, and the manufacturing stage, through testing to troubleshoot potential problems. Repeat the test to fully expose defects and failures.