He appeared on social news site Reddit, typing on his laptop some 220 miles (354 km) above Earth during the site’s “ask me anything” (AMA) session.
To “beam” his answers down, Mr Hadfield logged on via a satellite relay to a server in Houston, Texas.
“The purpose of all of this is to connect with you and allow you to experience a bit more directly what life is like living aboard an orbiting research vessel,” wrote the astronaut.
The discussion drew more than 2,000 questions and comments.
The astronaut replied to queries ranging from describing the smell of space, saying that “airlock smells like ozone, or gunpowder”, to clarifying how astronauts shaved when bits of hair floated all around them: “just wipe it on a cloth every time”
I feel like an adapted ape swinging through the jungle canopy… until I miss a handrail and crash into the wall”
He said that he did not see the meteor that fell in Russia because the station was on the other side of the Earth, but added that small meteorites “burn up between ISS and the Earth every day.
“I watched a large meteorite burn up between me and Australia, and to think of that hypersonic dumb lump of rock randomly hurtling into us instead sent a shiver up my back,” he wrote.
He said that sometimes occupants of the ISS “hear pings as tiny rocks hit our spaceship, and also the creaks and snaps of expanding metal as we go in and out of sunlight. The solar panels are full of tiny holes from the micro-meteorites.”
One of the questions was about weightlessness, and Mr Hadfield wrote: “Simply fly – to push off and glide magically to the other end of the station. It makes me smile to myself, every time.
“I’m still learning! But sometimes now, I am graceful. I feel like an adapted ape swinging through the jungle canopy… until I miss a handrail and crash into the wall.”
He also said that the launch – “all that power and acceleration” – was the biggest danger astronauts faced.
“Once we survive that, it’s just a steady threat of radiation, meteorite impacts, and vehicle system failure like fire or ammonia breakthrough,” he posted.
Describing how the world looked from space, Mr Hadfield wrote: “It looks like a carpet of countless tiny perfect unblinking lights in endless velvet, with the Milky Way as a glowing area of paler texture.”
He said that Australia looked “coolest”, calling the colours and textures of the Outback “severely artistic”.
“The most beautiful to me are the Bahamas, the vast glowing reefs of every shade of blue that exists,” he added.
Finally, when a Redditor asked: “If you discover intelligent life, who should play you in the movie?” Mr Hadfield said: “Someone with a good moustache.”
In March, Mr Hadfield will become the second-ever non-Russian and non-American to lead an ISS crew. A European Space Agency astronaut, the Belgian Frank De Winne, was in command of the station in 2009.
Mr Hadfield was the first Canadian to undertake a spacewalk; and he was the first and only Canadian to board the Russian Mir space station.
He was also the first Canadian to operate his country’s major contribution to the space shuttle – its robotic arm, or “Canadarm”.