News flash:
China Radio International reports: On May 4, the astronauts of the seventh long-duration International Space Station expedition, who were riding in the Russian "Soyuz-T MA1" manned spacecraft, returned to Earth. But on the way back, the spacecraft landed about 460 kilometers away from the intended landing site. According to information from NASA, this was very likely caused by an error in the design of the spacecraft's navigation computer software.
The navigation computer suddenly failed
According to reports, when the returning Soyuz spacecraft approached the atmosphere, its speed was as high as 25,000 feet per second, 25 times the speed of sound. Under normal circumstances, at that point the spacecraft should skim horizontally across the uppermost edge of the atmosphere, using air resistance to slow down. At this time, the exact point where the spacecraft meets the atmosphere is crucial. It cannot be too high, or the air will be too thin and the deceleration too slow; nor can it be too low, or the deceleration will be too fast. To keep the spacecraft from quickly "dropping" into the atmosphere, it has to maintain just the right upward force by adjusting its center of gravity and other methods. Achieving this delicate balance does not depend on the astronauts' experience, but on the precise calculations of the navigation computer. It must identify the spacecraft's exact position and determine which direction is "up."
But this time the Soyuz spacecraft's navigation computer gave a very unconventional performance. When the spacecraft approached the atmosphere, the autopilot suddenly "said" that it had forgotten where the spacecraft was and did not know which direction to fly next. Seeing such a "display," the astronauts were all stunned, and the three of them just stared wide-eyed, not knowing what to do.
Immediately afterward, the autopilot switched from normal mode to backup mode. The astronauts knew that in this situation, the autopilot would activate a simple backup program to keep the spacecraft stable and issue commands to make it rotate slowly. In the end, it still ought to bring them "home" safely, though with a lot more hardship along the way. So they decided to let the autopilot continue working. However, as a result, the Soyuz no longer tried to head "upward," but instead "dropped" into the atmosphere much faster than planned. The deceleration process sped up greatly, and the spacecraft's landing "trajectory" naturally changed quite a bit from the original plan.
A software slip-up caused the error
According to reports, the technology of spacecraft navigation computers had already become fairly mature in the late 1960s, and such errors rarely occurred. But the "Soyuz-T MA1" manned spacecraft that had just brought the astronauts "home" had only recently been improved and was carrying out an atmospheric reentry mission for the first time. So people guessed that it was most likely a slip-up in the improved navigation computer software that gave the astronauts such a scare.
Experts pointed out that if the spacecraft went off course because of a navigation computer software problem, then this problem should still be easy enough to overcome: ground personnel would only need to modify the software program. However, navigation computer software errors can not only cause a spacecraft to deviate from its course during return, but may also lead to even more tragic disasters. It is said that the navigation computers on two Soyuz spacecraft respectively "got dizzy" in 1988 and 1997, issuing fatal erroneous commands. Fortunately, the astronauts discovered it in time and intervened manually themselves, thus avoiding two looming "disasters."
As for the reason why the Soyuz spacecraft went off course, some people also believe it may have been caused by astronaut operating error. The head of the Russian company that manufactures and operates the Soyuz once suggested that it was very likely the American astronaut on board had pressed the button to activate backup mode, causing the spacecraft to behave this way. But the three astronauts on board said that none of them had touched that button.
China Radio International reports: On May 4, the astronauts of the seventh long-duration International Space Station expedition, who were riding in the Russian "Soyuz-T MA1" manned spacecraft, returned to Earth. But on the way back, the spacecraft landed about 460 kilometers away from the intended landing site. According to information from NASA, this was very likely caused by an error in the design of the spacecraft's navigation computer software.
The navigation computer suddenly failed
According to reports, when the returning Soyuz spacecraft approached the atmosphere, its speed was as high as 25,000 feet per second, 25 times the speed of sound. Under normal circumstances, at that point the spacecraft should skim horizontally across the uppermost edge of the atmosphere, using air resistance to slow down. At this time, the exact point where the spacecraft meets the atmosphere is crucial. It cannot be too high, or the air will be too thin and the deceleration too slow; nor can it be too low, or the deceleration will be too fast. To keep the spacecraft from quickly "dropping" into the atmosphere, it has to maintain just the right upward force by adjusting its center of gravity and other methods. Achieving this delicate balance does not depend on the astronauts' experience, but on the precise calculations of the navigation computer. It must identify the spacecraft's exact position and determine which direction is "up."
But this time the Soyuz spacecraft's navigation computer gave a very unconventional performance. When the spacecraft approached the atmosphere, the autopilot suddenly "said" that it had forgotten where the spacecraft was and did not know which direction to fly next. Seeing such a "display," the astronauts were all stunned, and the three of them just stared wide-eyed, not knowing what to do.
Immediately afterward, the autopilot switched from normal mode to backup mode. The astronauts knew that in this situation, the autopilot would activate a simple backup program to keep the spacecraft stable and issue commands to make it rotate slowly. In the end, it still ought to bring them "home" safely, though with a lot more hardship along the way. So they decided to let the autopilot continue working. However, as a result, the Soyuz no longer tried to head "upward," but instead "dropped" into the atmosphere much faster than planned. The deceleration process sped up greatly, and the spacecraft's landing "trajectory" naturally changed quite a bit from the original plan.
A software slip-up caused the error
According to reports, the technology of spacecraft navigation computers had already become fairly mature in the late 1960s, and such errors rarely occurred. But the "Soyuz-T MA1" manned spacecraft that had just brought the astronauts "home" had only recently been improved and was carrying out an atmospheric reentry mission for the first time. So people guessed that it was most likely a slip-up in the improved navigation computer software that gave the astronauts such a scare.
Experts pointed out that if the spacecraft went off course because of a navigation computer software problem, then this problem should still be easy enough to overcome: ground personnel would only need to modify the software program. However, navigation computer software errors can not only cause a spacecraft to deviate from its course during return, but may also lead to even more tragic disasters. It is said that the navigation computers on two Soyuz spacecraft respectively "got dizzy" in 1988 and 1997, issuing fatal erroneous commands. Fortunately, the astronauts discovered it in time and intervened manually themselves, thus avoiding two looming "disasters."
As for the reason why the Soyuz spacecraft went off course, some people also believe it may have been caused by astronaut operating error. The head of the Russian company that manufactures and operates the Soyuz once suggested that it was very likely the American astronaut on board had pressed the button to activate backup mode, causing the spacecraft to behave this way. But the three astronauts on board said that none of them had touched that button.
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C++ ☆☆☆ 中国ＤＯＳ联盟成员 ☆☆☆ C++
C++ ★★★ 爱提问的红色狂想 ★★★ C++
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