Once a physicist: Steve MacLean

Astronaut Steve MacLean is president of the Canadian Space Agency.

Steve MacLean

Why did you choose to study physics?
I grew up spending summers on a farm in Nova Scotia with my grandfather, and he was very interested in physics and astronomy. He still used old pioneering techniques on the farm, like work horses, pulleys and so on, and I think I learned more about engineering there than anywhere else. When I went to York University in Toronto as an undergraduate, physics was initially my worst subject, but soon I was doing well at it and enjoying it. When I started out, I am not sure I knew I was going to be a physicist, but it became natural, and after I graduated in 1977 I stayed on at York to do a PhD in laser and solid-state physics.

How did you become an astronaut?
After I got my PhD in 1983 I went to Stanford University in California to do a postdoc with Arthur Schawlow, who shared the 1981 Nobel Prize for Physics for his work on lasers. I was enjoying it and expecting to stay for a while, but then there was a call for astronauts back home in Canada. At first I did not apply because I thought it would be a lottery, but after someone told me they were looking for people with my training in physics and medicine, I changed my mind. Six months later, I was fortunate enough to be one of the six people selected. It is not like winning a race – they started with 5000 applicants and narrowed it down to six, but there are probably a few hundred people who could actually do the job. So you have to be lucky, really.

Tell me more about your medical training.
As an undergraduate I was a gymnast on the Canadian national team, and there was a lot of interest in what happens to athletes when they do a double back flip off the high bars. Sometimes, they were getting "lost", or disoriented, in mid-air. A friend and I worked on a biomedical approach to the problem, looking at what accelerations the brain was experiencing. We realized that you get lost if, at the apex of the motion, there is a horizontal component to your velocity. At that point, your inner ear is experiencing weightlessness, and your brain cannot interpret an extra, unexpected horizontal motion – essentially, doing the move in a particular way causes the inner ear to malfunction. I did not know it at the time, but the same kind of thing can happen when you go into space. Your inner ear is not calibrated anymore, and you get what is called "surround self-motion", where you shake your head and you see the walls moving back and forth, instead of being able to see stable walls, as we do on Earth. It is fascinating stuff.

What is it like to be in space?
It is an experience you cannot describe in a soundbite. It really takes several hours over a coffee or something to share what it is like. There are several aspects to it, but it is worth going up there just for the weightlessness alone. To have every single muscle in your body totally relaxed is a wonderful feeling, and when you look out the window in that state, at the Earth and its atmosphere and the universe – well, there is nothing that beats it. It is a phenomenal privilege to experience the view you get from up there. Some people do have problems sleeping in space; for example, if you sleep in a section of the International Space Station (ISS) where the airflow is poor, you can get a local excess of carbon dioxide, which will give you a bad headache. You also grow about 5cm when you are in space, and when fluid enters the interstitial region of the spine, it puts pressure on the spinal cord. Some astronauts get really bad lower-back pain from that and they cannot sleep because of it. But I found it wonderful. Floating around in your sleeping bag, you get the best sleep in the world.

What are the major goals of space exploration in the near future?
I think it is important to consider Mars as a target. In terms of its science, Mars is more complex than the Moon, and it can teach us lots about the Earth, in terms of geology and atmosphere. If Mars is a target, the next question is how to get there. Can we go directly? Should we go to the Moon first? Or an asteroid? One rationale for going to the Moon is that you need to try out new systems somewhere two days away from Earth before you try them a year away, which is about how long it takes to get to Mars. The ISS will also play a role, and you need to consider how much to use it to verify techniques and ideas that you want to incorporate on a longer trip. These things still need to be worked out. It would be premature for me to state what the answers are – it is easy to say "we should go to Mars and not the Moon", but it is actually the details that tell you whether that is the right thing to do or not, and that is what we need to look at. The role for unmanned vehicles is essential – they are precursor missions for what will come next.

Do you have any advice for physics students?
I would say that you do not need to be an Einstein to be good at physics. It is nice to have talent, of course, but talent is not enough unless you also work at it. When I was studying, I would spend a lot of time on just one page of a textbook, trying to figure out what was going on – that is the nature of physics. But it is a good field to be in; there are a lot of challenges and there is still a lot more to be done. I think it was Bertrand Russell who said there were only two things in the world – physics and philosophy. I am biased, but I think there is a shade of truth in that.

This article originally appeared in the December 2009 issue of Physics World

last edited: March 28, 2014

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Once a physicist