Robert Thirsk spins in zero gravity in July as high school students look on via a video link from the International Space Station. Thirsk, who spoke via satellite with Canadian educators on Tuesday, is the first Canadian astronaut to have an extended stay in space. (Jeff McIntosh/Caandian Press)

Canadian astronaut Robert Thirsk and an American colleague gave Canadian teachers a rare glimpse into life in space on Tuesday, talking about their day-to-day lives in orbit, from drinking recycled water to running on a treadmill in zero gravity.

Thirsk, a New Westminster, B.C. native, and U.S. crewmate Michael Barratt spoke via satellite to the seventh annual Canadian Space Educator Conference from the station, taking questions from some of the conference's 130 participants.

Thirsk described his arrival in May to the station aboard a Russian Soyuz rocket as a "gentle" ride, particularly when compared with the relatively bumpy first stage of launching a space shuttle.

Thirsk is on a six-month mission aboard the International Space Station, making him the first Canadian to make an extended stay in space.

To combat the loss of bone and muscle mass that comes with spending time in a zero gravity environment he works out two hours a day, using a stationary bike, a resistance-based fitness machine and a treadmill equipped with a harness that forces the astronauts to carry a load as they run.

Thirsk, who acts the station's medical officer, said so far he has been lucky in that few major illnesses have occurred.

Improving space education a goal for CSA

It was the first time Canadian teachers and a Canadian astronaut in space have had a chance to communicate directly, and the Canadian Space Agency hopes the experience might help improve space and science education across the country.

However, even teachers can't resist asking astronauts about what it is like to drink water recycled from urine and sweat.

Barratt gave an unusual answer, describing the emotional response to drinking the concoction as "exhilarating." He said it was in keeping with the mission of space explorers to find new ways to get by with fewer resources, and the reconstituted water represented the ultimate example given how water is in short supply.

"It's an incredible relief and very wonderful thing," he said. "We're exhilarated in what we've achieved."

Thirsk defended the cost of the space station and Canada's contribution to space funding, saying Canada's taxpayers contribute $300 million a year to the space agency while space industry companies in Canada in turn generate revenue of more than $2 billion.

Thirsk said there are also benefits that can't be quantified in dollar values, including inspiring the public to pursue the impossible and encouraging young people to pursue careers in science, technology and mathematics.

"The cost is a bargain," he said.