Canadian astronauts Robert Thirsk, left, and Julie Payette flank federal Industry Minister Jim Prentice as they look over a model of the space station during a news conference in Montreal on Feb. 11, 2008. Payette will head to the International Space Station aboard the space shuttle Endeavour for mission STS-127, with the launch planned for April 2009. Thirsk is scheduled to depart on a Russian Soyuz rocket in May 2009 and will be the first Canadian to remain on the space station for a long stay. (Paul Chiasson/Canadian Press)

Robert Thirsk is one of two Canadian astronauts scheduled to visit the International Space Station in 2009, along with Julie Payette. But unlike Payette, Thirsk isn't simply visiting the station as part of a shuttle mission: he's there for the long haul. Thirsk, 54, is set to become the first Canadian to live on the space station for an extended period of time — a tour of duty likely to last as long as six months.

It will be the second trip into space for the native of New Westminster, B.C.: his first was in 1996, as a payload specialist aboard the space shuttle Columbia in 1996. This time, though, he'll be going on a Russian Soyuz rocket, which is set to blast off in late May 2009.

As with most of the men and women who become astronauts, Thirsk is an overachiever: he has a master's degree in mechanical engineering and an MBA from MIT and a doctorate in medicine from McGill.

He spoke with CBCNews.ca about the unique medical impacts of long-duration space travel, his work and the future of Canadian astronauts.

What kind of physical changes are going to happen to your body during your four to six months aboard the station? How do you prepare for those changes?

The health problems associated with long-duration flight are different than for short-duration space flight. For long-duration space flight, I will experience muscle atrophy and loss of performance of my muscles. My bones will lose calcium in a manner very similar to osteoporosis, which affects the geriatric population. I'll also be exposed to higher fluxes of ionizing radiation, which has risks associated with that.

And the other area we're trying to focus on is the psychological affects of isolation and confinement. Living aboard a space station is not like living in a four-star hotel. It's living in a rustic condition, we eat freeze-dried food, we have no fridge or freezer on board, there's no shower, there's no bathtub and so it will be rustic living. I do think the psychological aspects will be the most difficult for us.

In terms of preparing for it, physically we do our best by getting as fit as possible prior to launch. I'm working hard to build up my musculature in my legs and in my upper body, as well as my bone mass prior to flight. I know during the flight I'm going to lose muscle and bone mass so I'm trying to get ahead of the curve before I even launch. There's no formal diet program. We just try to eat sensibly, try to have high protein as much as possible to complement the fitness program on the ground. There's no target for weight increase. Once I'm in orbit, I'll spend a significant amount of time during my day — two and half hours — doing physical exercises: not to stop but to try to minimize the rate by which my muscles and bones become weak.

Is it not possible to stop?

We have tried nutritional supplements in the past and we've tried to do exercise programs in orbit; they alone do not work. Soon, and probably with my expedition, we're going to be testing some experimental drugs — drugs that some osteoporosis patients are using on Earth now to see if that will also help prevent the loss of bone mineral during space flight. So it may be that a combination of nutrition, an on-board exercise program and pharmaceutical supplements may stop the loss of muscle or bone, but each alone will not do the trick.

You mentioned the isolation. How have you trained for that? What kind of experiences have you had that have come the closest to simulating what it will be like aboard the station?

As part of the training program we do take part in ground-based expeditions. I spent 11 days underwater at the National Undersea Research Center located in Key Largo, Florida, with five other astronauts. We designed it as a space station mission and we functioned as astronauts during this period of isolation underwater. I've also done winter survival courses in sub-zero temperatures in mountains in Wyoming for a two-week period of time and also up in the wilds of Alaska as well, both with potential long-duration astronauts.

And what's good about each of these experiences is that it takes us out of our comfort zone. For example, when we were doing our winter survival course, there's nothing on our minds other than food, water, and shelter and keeping warm. Everything else is not important. So we really do get out of our comfort zone. And it's only in those situations where you are able to realize what your own weakness and strengths are and the weaknesses and strengths of your astronaut colleagues as well, and then work as a team to meet everyone's needs.

What did you learn about yourself?

The most important thing for me is I need to learn how to pace myself. I do have experience on a short-duration flight and for each of those 17 days in space I was able to go 100 per cent to accomplish all of the mission objectives. During these expeditions in the wilderness, I would go 100 per cent from day one, but what would happen by day six, seven, eight, my productivity and my mood and my efficiency would begin to drop and that's because I didn't pace myself earlier in the mission. So the lesson for me during my stay aboard the space station will be to pace myself and not be too enthusiastic and not be too dynamic on the first days and weeks of the mission so I have that reserve during the fourth and fifth months.

You'll be one of the first members of a six-person crew aboard the station. You've likely heard from astronauts who've been aboard two-or three-member crews, but how do you think the dynamic will change when there are so many people aboard the station?

I'm not sure what the impact of having six people up there will be. No one has ever mentioned to me that they've ever had any difficulty dealing with their one or two crewmates during the previous space station expeditions. Astronauts are well trained or well selected to function as a crew, so everyone has always enjoyed flying with their one or two crewmates. After their expeditions are over, these people are still considered life-long friends. But I think it will even be better with six. I know all of the other astronauts I'll be flying with, I've either met them all in training or I've socialized with them before and I love all of them. I could not have put together a better group of crewmates than what the committee has selected for [space station] expedition 19.

Do you know what your duties will be on the station?

The crew roles haven't yet been divided yet. However, being Canadian, I know that I'll be the prime operator for station robotics. That's pretty cool because during expedition 19 the Japanese cargo vehicle — called HTV (or H-II Transfer Vehicle) — be launched and docked at the station. But it does not dock itself to the station. What it will do is it will hover close by and then the Canadarm robotic operator will need to grapple it and berth it to the station. That's pretty exciting. And there's always robotics work associated with spacewalks or repairs to the station.

You're the first Canadian to have trained to fly on a Soyuz rocket, a vehicle that will take on added importance after the U.S. shuttle program winds down in 2010. Is that kind of training something that will be mandatory for future Canadian astronauts?

As you know, Julie Payette is going up on the shuttle before me. And after I go, there will likely be an opportunity for one or two more Canadians to fly long-duration expeditions in years following. The Soyuz vehicle not only functions as a transport vehicle for the space station, it also functions as a lifeboat and that means that every astronaut aboard the station be proficient in the descent flight of a Soyuz vehicle.

What can you tell us about the difference between riding on a space shuttle versus a Soyuz rocket?

The technology that's associated with the Soyuz vehicle is not that different than what Yuri Gagarin flew in back in the '60s. Certainly the avionics have been updated, but basically it's the same fundamentals of space flight used today as it was decades ago. Soyuz is a very reliable spacecraft. Its safety record is very good. It isn't impaired by things such as bad weather at the launch site. Once it's given a launch date, it will launch on that date.

The space shuttle is an incredible space vehicle and it's multi-use: it functions as a rocket, an orbiting laboratory, an orbiting construction and assembly site, and as an airplane when it returns home, and it has incredible cargo capacity, 40,000 pounds at a time. But this versatility … has drawbacks as well. It cannot launch in bad weather and then it does have problems such as foam falling off the external tank. So both vehicles are incredible vehicles for different reasons and I like to think they compliment each other.

The space shuttle Columbia met with disaster in 2003 because of damage caused by foam falling from the tank. You flew on Columbia in 1996. What do you remember about that day and about the shuttle?

Well, the worst thing associated with the Columbia accident was losing seven very capable and seven very dear friends. That was the worst part of it. But of course having flown on that space shuttle, you do have a bond with your vehicle. There were four different shuttles at the time, so losing Columbia was also a loss. I was totally amazed during my 17 days space shuttle flight that this vehicle was able to keep me alive in such a remote hostile environment. So I had love and respect for the vehicle. But to lose the crew was of course much worse.

What direction do you think the Canadian astronaut program should evolve to after the shuttle program winds down?

I hope that the space station will remain in orbit and remain a world-class research station for years to come. But in addition we know that the United States is looking at human exploration missions to the moon and Mars. It's important that Canada is a part of an international effort to develop a moon base and I'd also like to see Canadians be a part of the first expeditions to Mars in the years or decades to come.

I've heard it suggested that one direction we might take is for Canadian astronauts to specialize in the field of medicine, to act as "space paramedics" for future missions. What do you think of that idea?

Earlier you asked me about my roles and responsibilities on the station and I forgot to mention that I've been given specialist training so that I could function as the crew medical officer. I would like to see enhanced capabilities for medical care on the space station, on the moon base and on the vehicles that take astronauts to Mars. When we fly in the space station, the primary medical support or guidance we receive is on the ground. The flight surgeon remains on the ground and we have some limited capabilities and expertise in orbit. But as we get further and further away from low-Earth orbit, we need to have more medical care facilities in situ on the moon base or the vehicle itself.

I think one of Canada's strengths is its strong medical teaching program. The medical schools in Canada are amongst the best in the world, so I think we should exploit that. It would be a mistake to have an astronaut that only has medical expertise, though: they have to take other generalist roles as well. But we certainly should exploit Canada's reputation as a trainer of clinicians.

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