Major General Yang Liwei, the first Chinese citizen to travel to space and orbit the Earth in a spacecraft, remains adamant he heard loud "knocking" sounds several times during his historic flight aboard the Shenzhou 5 spacecraft on Oct. 15, 2003.

And he's not the Chinese astronaut or taikonaut to have reported hearing this knocking sound seeming to originate from outside their spacecraft. Other Chinese taikonauts (who haven't been identified) reported hearing the same knocking sound, too.

Like Us on Facebook

The China National Space Administration (CNSA), China's equivalent of NASA, isn't investigating this phenomenon and hasn't officially commented on it.

Shenzhou 5 with then Col. Yang as its only passenger completed 14 orbits of the Earth in the historic mission lasting 21 hours and 23 minutes. The spacecraft landed Oct. 16 in Mongolia.

In a recent interview with Chinese media, Gen. Yang said he heard "someone knocking the body of the spaceship just as knocking an iron bucket with a wooden hammer."

He said he was baffled by the noise which he said appeared "suddenly without any reason," and was repeated on more than one occasion.

"A non-causal situation I have met in space is a knock that appeared from time to time," he said.

"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."

Admitting to being unnerved by the sound, he did what any normal Earth bound human would. He peeked outside the spacecraft's small window to see it there was anyone -- or anything -- out there. He saw nothing except the blackness of space.

Thirteen years after this mysterious event and he's not been able to figure out what it was. He said he even tried but failed to recreate the sound so Chinese experts could help him identify it.

Dismayed by his failure to logically explain the knocks, Gen. Yang now accepts the sound as a "normal phenomenon" in spaceflight.

What makes Gen. Yang's story all the more bizarre is that you can't hear any sound generated in space because the vacuum permeating space doesn't transmit sound waves. That he clearly heard a loud knocking sound coming from outside the spacecraft in strange indeed.

Chinese media also reported other taikonauts on missions in 2005 and 2008 hearing knocking sounds.

Gen. Yang, 51, is now Deputy Director of the China Astronaut Research and Training Center and also Deputy Director General of China's manned space program.

TagsMajor General Yang Liwei, Shenzhou 5, Chinese astronaut, taikonaut, China National Space Administration, knocking sound, china