While many space enthusiasts fantasize of being launched into orbit, this is regrettably not an option for many of us.

So, the next best alternative is to read interviews with people who have been fortunate enough to travel into space at some point in their lives.

Of course, many people have already explored outer space, and their experiences have varied.

Yang Liwei is one of the fortunate few who have ventured into space; in fact, he created history in 2003 by becoming China’s first astronaut.

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He traveled to space on the Shenzhou 5 spacecraft, making China only the third country to send an astronaut into space on its own.

Only the United States and Russia had previously launched astronauts on their own, so China undoubtedly made some history.

While Liwei made history just going to space, what he reported while there is equally compelling.

Yang was taken to space in 2003 for a 21-hour mission, but in an interview, he revealed how nervous he was after hearing a ‘knocking’ on board the Shenzhen 5 spacecraft.

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“A non-causal situation I have met in space is a knock that appeared from time to time,” according to him.

“It neither came from outside nor inside the spaceship, but sounded like someone is knocking the body of the spaceship just as knocking an iron bucket with a wooden hammer.”

The former astronaut went on to add that when he heard the sound, he became worried and glanced out the porthole to see what was causing it.

However, Liwei saw nothing noteworthy, which further increased his suspicions.

Liwei was obviously not hearing things, as other Chinese astronauts on the Shenzhou 6 and 7 spacecraft in 2005 and 2008 reported hearing the same sound.

So, now that we know China’s first astronaut to go to space isn’t crazy, what are the possible causes of the noise?

The first option is that space junk struck the spaceship, which appears doubtful.

A more likely explanation for the noise is that the spacecraft expanded and contracted in the low-temperature environment of space.

When Liwei returned to earth’s atmosphere, he could no longer hear the commotion from the shuttle. However, he made every effort to reproduce it in order to check if technicians would recognize it.