Chinese Shenzhou-20 spacecraft suffered a through-crack in its reentry module porthole caused by tiny space debris. Mission command delayed the return to ensure astronaut safety.
During a routine inspection, Chinese astronauts discovered an unusual mark on the edge of Shenzhou-20ās reentry module porthole, just one day before its scheduled return to Earth. Jia Shijin, chief designer of the manned spacecraft system at the China Academy of Spacecraft Technology under the state-owned China Aerospace Science and Technology Corporation (CASC), revealed details of the emergency response in a recent interview with China Central Television (CCTV).
Discovery and Assessment
At first, the mark was not identified as a crack. Jia said, āIt was just a triangular mark, small in size. After an initial review of the images, it was difficult to determine what exactly it was. It looked like some kind of paint or coating stuck on the surface.ā
To assess the situation, the crew took additional photos from multiple angles and under different lighting conditions. They also used the camera on the space stationās robotic arm to inspect the porthole from the outside. Once the images were transmitted to Earth, experts in glass materials were urgently convened to study the damage. After careful analysis, they reached a consensus: it was a through-crack, fully penetrating the porthole from the inner surface to the outer surface.
Risk Evaluation and Response
Jia described the teamās reaction: āWe were astonished. The chance of the spacecraft being hit is already extremely low, and for the porthole to be affected is even more unlikely.ā
The porthole has a three-layer structure, with the outermost layer serving as a thermal protection shield. During reentry, it endures frictional temperatures exceeding 1,000Ā°C. The crack essentially created a breach in this safety system, highlighting a significant safety risk.
Within 12 hours of confirming the crack, the mission command decided to postpone Shenzhou-20ās return to prioritise astronaut safety. The team then conducted a thorough review of the portholeās design, manufacturing, and test data. Jia stated, āAfter careful review, we have even greater confidence in our product, its original design philosophy, and all ground-based tests and verifications. The most likely cause of this crack is space debris.ā
He explained that the debris was smaller than 1 millimetre but travelled at extremely high speed. āIn ground tests, ordinary tools cannot reproduce such damage. We had to use a hammer,ā he added.
Safe Return of Astronauts
Finally, astronauts Chen Dong, Chen Zhongrui, and Wang Jie returned safely to Earth. Their health is reported as good. Earlier, the Shenzhou-21 spacecraft also landed successfully at the Dongfeng Landing Site on November 14th.
Additional reporting by HKCNA, Global Times.
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