#BBCtrending: Spaceman Chris Hadfield tells his social media secrets
27 December 2013 Last updated at 07:33 GMT
Chris Hadfield was the first Canadian to walk in space - but he's probably better known for being a YouTube star.
While up on the International Space Station, he produced hours of content for social media. His biggest success came with his cover version of David Bowie's Space Oddity, which has been viewed almost 20 million times.
Hadfield told #BBCtrending's Anne-Marie Tomchak the secrets of his online success.
Produced by Benjamin Zand
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