Yang said that according to what he learned the knocking sound was a result of decreasing air pressure that caused changes in the structure of the spacecraft as it left Earth for space.
杨利伟说：“我了解的情况，可能是因为我们的飞船在地面时会有压力，太空是真空无压力的环境，有可能结构会有一些变化，会产生一些声音。”
Yang said that according to what he learned the knocking sound was a result of decreasing air pressure that caused changes in the structure of the spacecraft as it left Earth for space.
杨利伟说：“我了解的情况，可能是因为我们的飞船在地面时会有压力，太空是真空无压力的环境，有可能结构会有一些变化，会产生一些声音。”
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