Q&A: an ISS astronaut
Time spent on the International Space Station (ISS) is helping scientists understand the effects that long stays in space have on the human body
What side effects do you experience living on the ISS? In space your body experiences a lot of changes, although you’re not aware of them all. About half of astronauts suffer from something called space adaptation syndrome, which is similar to being seasick and is caused by the disconnect between what you perceive and what your vestibular system is telling your brain. Luckily, I didn’t feel sick but I did experience a pressure in my head for about a week. This is brought on by the redistribution of bodily fluids towards the upper body and makes you feel congested; some astronauts feel like they have a cold for their entire stay.
How did your body cope returning to Earth after 200 days in space?
Space adaption is a lot easier because you’re moving from effort to effortlessness, but it’s the opposite on return as you’re going from this absolute lightness to carrying your own weight. You feel incredibly heavy; your brain has to re-learn how to estimate weight and you tend to not use enough force to move objects.
The first time I tried to walk after returning to Earth it felt like I was trying to balance a big rock on a couple of toothpicks! Fortunately, this only lasted for 24 hours.
Your cardiovascular system is also fatigued, as your heart and valves readapt to pumping blood around your body against gravity. For the first few days back on Earth, I felt tired and I had an elevated pulse, even at rest. I slept for 12 hours a day; it was my way of gauging that my cardiovascular system was still suffering.
How long was it before your body returned to normal? We undergo tests before and after a spaceflight and this helps to determine if you’ve returned back to pre-flight condition. It took about 10 days for my vestibular system to normalise. In terms of our muscles, we come back in good shape because we exercise a lot on the ISS. However, we don’t tend to use our postural muscles in space, which help you to sit or stand up straight. These muscles are typically difficult to train in a gym and so they shrink. From the moment you’re back you begin activating them again, so they return to normal after a few weeks.
What research did you do on the ISS into long duration stays in space?
In weightlessness, you destroy more bone mass than you build anew. One experiment, called NATO (nanoparticlebased countermeasures for microgravity-induced osteoporosis), investigates whether it’s possible to maintain bone density by adding specific types of nanoparticles to bone cell cultures. It’s not only for the purpose of long duration spaceflight, but also to see if it may be useful clinically.
Were you the object of any of the experiments? Yes! One investigated how the brain adapts to control balance and movement in the absence of a reference system. For example, your feet on the ground send a signal to your brain on how to maintain balance, which you don’t have in space. I had to repeat a series of movements with sensors attached to my body, and we were able to compare the results to a set of data I had completed before the mission.
What are the challenges in getting humans back to the Moon or to Mars?
Astronauts will have to be well trained, because they will have to be more autonomous. On the ISS you can rely on almost real-time communication with an army of specialists on the ground who are there to troubleshoot and help you. As you get further from Earth that’s going to become impractical very quickly.
If something goes wrong, astronauts will need to be able to solve the problem in a more autonomous way; they will need to be able to access a repository of knowledge and advanced automatic assistance to help them to troubleshoot any technical malfunctions. The other issue is that there’s not much to do on the way to Mars; astronauts will have to cope with a long journey on a spacecraft that is probably going to be small, because it’s expensive to send mass to Mars.
> Turn to page 61 to learn more about life on the ISS