In his most-viewed clip, Hadfield, 53, shows how even the mundane can become spellbinding without gravity. When he wrings a soaking cloth, the water leaves it but its surface tension means it won't go any further, so it forms a rippling tube that amazes Hadfield as much as the seven million people who have watched his experiment.
Other hits filmed when Hadfield isn't conducting official experiments in man's remotest laboratory - or speaking live to groups of rapt schoolchildren - show how astronauts sleep, shave, cry and recycle their urine (yes, for drinking). His second-most-viewed video doesn't feature him at all, but a 27-second close-up of nuts floating around inside their tub.
Equipped with cameras and big zoom lenses, Hadfield also takes photos of rivers, cities, oceans and deserts - whatever catches his eye out the window. He shares them with captions that recall something of the early wonder of the "earthrise" and "blue marble"photographs that first revealed the beautiful fragility of our planet. The winning combination of profundity and giddy enthusiasm is not new to Hadfield's son Evan. "It's tough not to be biased," he says from Germany, where he lives, "but Dad's one of those people who only come along every once in a while."
Even so, Evan, 28, says he has always been cool about having a spaceman for a dad - he was 10 when Hadfield first went into orbit (this is his third mission) - but he gets why so many others are in awe. Our idea of space these days tends to concern "missions and machines", he says, adding: "Rarely do you see the focus on the individual. We've seen thousands of pictures from space but people are interested in Dad's because they're taken by a man just like them."
Hadfield jnr must also take credit for his father's rocketing profile. He works in parallel with the Canadian Space Agency, which edits and posts the videos, as Hadfield's social-media mission control. He receives text from space via email for captions and manages his dad's Twitter, Facebook, Tumblr and Google+ accounts. "I told Dad at the start not to expect too much. But I don't think an astronaut has had this level of media success since the Moon landings."
Hadfield has almost 750,000 followers on Twitter alone, providing priceless PR for Canada's space programme. Frustrated with low public interest in its online content during previous missions, it planned Hadfield's well in advance, deciding to focus on fun, informative videos. "What was not planned was the response," says Julie Simard, senior communications adviser to the Canadian Space Agency. She and the Hadfields have received thousands of emails from fans and from producers and publishers - and teachers who have used Hadfield's work in lessons.
Chris Riley is a British astronomy writer and the co-director of the 2007 documentary In the Shadow of the Moon. He says Hadfield has helped to put the man back into space. "In the early days of human space flight, training required an element of precision and accuracy that didn't always allow room for emotion. But now more than 500 people have flown into space, and there's room for a wider spectrum of personality."
Hadfield knows precision - he has a degree in mechanical engineering and is a former test pilot - but he also has an emotional attachment to space, born on an Ontario corn farm. He was 9 when he watched Neil Armstrong's lunar landing on television at his parents' farm. Racing outside to gaze up at the Moon, he knew where his future lay. "Everywhere he's got he learnt growing up on that farm," Evan says. "He's a smart guy from a small town. It's hard for him not to be folksy."
As those live broadcasts showed, space has also always been at the forefront of communications technology. While today's tools and a media-savvy son (Evan has an MBA in marketing) have amplified Hadfield's personality.
Where next for Commander Hadfield? He has said he'd volunteer to go to Mars, even on a one-way mission. But if that doesn't happen in his lifetime, perhaps a second career in music beckons. He plays guitar in several astronaut bands and in February performed a duet from space with Ed Robertson, the frontman for Barenaked Ladies.
Hello spaceboy
The wit and wisdom of Commander Chris Hadfield
On weightlessness: "Imagine floating in a pool without water."
On lift-off: "Launch is like being shaken in a huge dog's jaws, while pushed from the Earth by an unstoppable unseen giant force."
On the weather: "Lightning at night is awesome - thousands of km of arcing light and power... and hurricanes are HUGE - like Jupiter's red spot."
On orbiting Earth: "A great way to see the world - around it in 90 minutes! Gives 16 sunrises and sets a day - beyond beautiful."
On the view of Southern England at night: "The lights act like a census."
On the desert: "These mouthwatering generous folds of icing are actually Saudi sand."
On down time aboard the space station: "ISS end-end races, zero-G hide and seek, and velcro darts."
On Earth: "In proportion, our atmosphere is no thicker than the varnish on a globe. Deceptively fragile."
- Independent
