A few weeks ago, Chris Hadfield's name was not so well known, even in his native Canada.
The 53-year-old may have been the country's most experienced astronaut, the first Canadian to walk in space and a veteran of two Shuttle missions, but few people would have stopped him in the street to ask for an autograph.
Then, on December 21, Hadfield (pictured) arrived at the International Space Station for his latest mission and everything changed.
In a deliberate campaign to take earth by storm, Hadfield harnessed the power of social media to inspire the sort of interest in space exploration that Nasa and other agencies have been trying to attract for more than a decade.
Now he is on the way to becoming a star in his own right, the first internationally recognisable astronaut since the grainy black and white television images made Neil Armstrong, Buzz Aldrin and the original Apollo astronauts into superstars.
Hadfield used his Twitter feed and a high-powered camera to bring the beauty of the world, as well as the banalities of space, to hundreds of thousands of people on social media.
With seemingly incessant 140-character bursts accompanied by stunning photographs, shot from a glassed-in section at the bottom of the space station orbiting 400 kilometres above the earth, the former fighter pilot with a love of music and a poet's turn of phrase has seen a 15-fold increase in Twitter followers since he blasted off on a Soyuz rocket before Christmas.
It's not just Twitter. He took part in an "epic" Ask-Me-Anything session on internet forum Reddit last Sunday - under the headline "I am astronaut Chris Hadfield, currently orbiting planet earth" - that drew 7,786 comments.
He has made slick YouTube videos about life on the space station. And on Friday he and two colleagues did Nasa's first live Google+ Hangout from space, answering questions submitted during a live video downlink.
But this social media blitz is no accident. It is part of a plan cooked up before Hadfield's latest mission began. Elder son Kyle, 29, came up with the idea to get his father's space message out through Twitter, while younger son Evan, 27, runs the unofficial mission control from Darmstadt, south of Frankfurt in Germany. He devotes up to 16 unpaid hours each day to run his father's various social media sites, including Facebook, Tumblr and Google+.
"Dad wanted a way to help people connect with the real side of what an astronaut's life is - not just the glamour and science, but also the day-to-day activities," he said, noting that neither Nasa nor the Canadian Space Agency manages the images posted to the web or interactions with the astronaut's 420,000 followers.
The effect of Hadfield's undertaking, which has featured breathtaking photographs of January's Australian wildfires, a spider's web of Beijing streetlights and the green hue of the northern lights overlooking Britain, follows in the great tradition of Armstrong and Aldrin's moon landing in 1969, or the Apollo 8 crew's photo in 1968 of the earth rising on the moon's curved horizon, which helped fire the public's enthusiasm for space exploration.
"He's managing to grab the attention of segments of the public that were not typically interested in the space programme," said rookie Canadian astronaut David Saint-Jacques.
Hadfield also beamed back video showing how astronauts prepare meals and explained why tears sting in space, because they stick in one's tear ducts rather than roll down one's face. He took his guitar to the space station, both to pass the time and record original music.
"We have to view spacecraft and the space station as a place where people live, not just as life rafts where you barely survive," said Saint-Jacques.