The source of the bewildering knock on Chinese spacecraft

The mysterious knock on the surface of the spacecraft that has caused veteran astronauts to panic is not caused by aliens but the result of a change in air pressure.

Astronaut Yang Liwei said the mysterious knock he heard during his first flight to space was due to changes in air pressure.(Photo: Xinhua).

Yang Liwei, China's first astronaut, attracted a lot of attention when he revealed that he had heard an inexplicable sound like " wooden hammer knocking on a metal bucket " in a TV interview at the end. November. This sound came from Yang's spaceship in the 2003 mission, which made him very confused.

On December 1, when the famous astronaut attended an event at a school in Ningbo City in the eastern province of Zhejiang, the students raised many questions about strange sounds, Xinhua reported.

Yang answered this knock as a result of reduced air pressure , causing a change in the airship structure as the ship left Earth and entered space. According to Yang, the air leaking from the vessel's contents also made sounds. " I think it's quite normal. It is necessary to carefully identify the cause, " Yang said.

Yang's explanation fits with the report of space scientist Liu Hong posted on Guokr.com, China's famous scientific journal. In the report, Liu said that the sound comes from very small deformation in the spacecraft's inner layer material due to pressure changes .

Liu is the chief designer of Lunar Palace 1, the basis for testing life-support biological regeneration systems that plays an important role in Moon base construction. Liu said in a manned test in a 105-day airtight environment, researchers in the spacecraft also heard similar sounds. " They thought someone knocked on the door but did not detect anyone. At first, they were a bit excited but then became calm when looking for sound sources ," Liu recalls.

Finally, the team found that changes in spacecraft temperatures could lead to changes in air pressure, and differences in pressure between the inner and outer shells of the spacecraft causing small distortions at fabrication material, producing "Dong! Dong! Dong " sound.

"We may encounter all kinds of difficult explanations in the process of discovering the unknown, but we should seek scientific explanations. That's what drives us forward , " Liu said. .