”And then you look at the Earth when you have a moment. That usually takes up a lot of the free time.”Christer Fuglesang, docent in particle physics and Sweden’s first astronaut, describes his time in space as an amazing experience, especially the view over Earth. He continues: “The weightlessness and the spacewalks were also really special.” After two space shuttle missions, Fuglesang spent a total of 26 days, 17 hours and 38 minutes in space, including 31 hours and 54 minutes spread over five spacewalks. For these two missions, Fuglesang trained for over 13 years, and rightly so, for being in space is physically very challenging. “A lot, if not all, of our physiological systems are affected in space. Especially by the microgravity”. There is a whole branch of medicine called Space physiology, dedicated to the study of how our body functions in space. It is a unique environment, with microgravity and high radiation that affects the human body in a way that has never been experienced before. While we strive to go further into space, many of the potential showstoppers lie within the medical field.
On the question how Fuglesang became an astronaut, he laughs and says that it is a hard one to answer. “The short version is that I saw an ad, applied and was lucky enough to get the job.” And he continues: “But why did I apply? I have always been interested in space. I used to speculate a bit about how amazing it would be to go to space and that if I got the chance, I would have to take it. Then suddenly I saw an ad. At that time I had no idea they even had an astronaut program in Europe.” He describes the admission process as being long and tiresome, consisting of for one thing, medical tests with over 500 parameters. Finally, he became one of five European astronauts to be sent up to space and the International Space Station, ISS.
On the 10th of December 2006, the space shuttle Discovery was sent off to space, making Fuglesang the first Scandinavian leaving the Earth’s atmosphere. He would later return to space in 2009, completing his second mission. Fuglesang describes the time in space as wonderful but adds that he was lucky, from a medical perspective: “Many get sick more or less instantly, suffering from something called Space Adaptation Syndrome. I felt it in the beginning, but then I managed to focus on something else.” The syndrome, more simply space sickness, is due to the adaptation of the vestibular system to microgravity and is related to motion sickness. But space sickness is not the only difficulty the astronauts encounter. “Another problem is that many astronauts suffer from back pain in the beginning of their stay. The spine gets longer in space, or more accurately, it is not compressed as it normally is on Earth. But the pain usually subsides after a few days.”
A third problem the human body faces in space is that the microgravity no longer pulls the water down towards the legs. Therefore, the water balance in the body changes. “You lose a lot of fluid that you don’t need and your face will seem plump. It is also really important that you drink before landing, otherwise you risk losing consciousness.”
The astronaut’s everyday-life is planned to the minute and has been practiced over and over again. Amongst other things, they’re scheduled to sleep for eight and a half hours, work for eight and a half hours and exercise for two hours; the latter is essential for the maintenance of muscle mass. However, research and science is gaining ground, becoming increasingly important on the missions and on ISS for each day. “Now, when the ISS is starting to be completed, more and more time is spent on research. A big part of that research is being done on physiology.”
Fuglesang describes the return to Earth as “tough”. He brings up the re-introduction of the Earth’s gravity and the stress it places on the body in particular. “To stand up when you are back on Earth is hard. Moreover, the sense of balance is really disturbed, especially during the first day. Again, some get sick but I was lucky enough to avoid that.” Even though Fuglesang has no upcoming space missions, he is still very clear on the future of space exploration: “The vision is to go further and be away for increasingly longer periods of time and space physiology is an essential part of that. Except for weightlessness, the other significant problem that needs to be dealt with is the radiation. It is not only about exploring space. Equally important is using our knowledge to improve life on Earth. It is usually said that a lot of what the body undergoes in a state of weightlessness is analogous to ageing and we are therefore using it to understand how ageing works. One example of that is osteoporosis. You lose bone mass in space, and we are not really sure what drives that.”
Professor Dag Linnarsson agrees with Christer Fuglesang. “The biggest remaining challenge that remains to adequately study is the degradation of the bones, i.e. the process of demineralisation.” Linnarsson is a well-known figure in space physiology, having worked with NASA, European Space Agency and having been the chairman for the Swedish committee that appointed Fuglesang as Sweden’s top candidate for the recruitment of astronauts. “There are a number of difficulties. It is a slow process, where the rate of demineralisation is a few percent per month, precisely on the limit that we can detect. […] In principal, you could say that the loss of calcium from bones during one month in space is equivalent to that normally lost in one year.”
Having started his career in space physiology in 1976, Linnarsson has been particularly interested in the effect of gravity on the distribution of gases and blood in the lungs and what happens in microgravity. “We know that gravity pulls down blood to the lower parts of the lungs or the posterior parts if you are lying on your back, as well as changing the dimensions of the alveoli so that they expand most at the bottom when you are inhaling.” he explains and continues: “When you take away gravity two, things can happen. Either the distribution of blood and gas in the lungs is optimised, or the distribution becomes chaotic. Without gravity, how can the blood know where the gas is travelling and vice versa?” Nonetheless, Linnarsson and the researchers have had an advantage compared to older generations concerning an issue that could have potentially stopped space exploration in its tracks. “Ever since Gagarin’s flight in 1961, we at least knew that you’d survive.”
The study of physiology in space is unique. Life has evolved with gravity and without it, every part of the human body is affected. As Linnarsson puts it: “If you want to understand how it normally affects the body, it is not enough with turning people upside-down and back to front to see what happens. One way of understanding the effect of gravity is to see what happens when you remove it.” The knowledge of the impact of gravity is not only useful in space. Understanding the interaction between gravity and the lungs can help understanding how particles on Earth damage the lungs and where the damage accumulates. Linnarsson and Fuglesang share the confidence that research in space physiology will help people clinically on Earth. They also share another vision: the missions will go further and the astronauts will be away for longer periods of time. For that they need a new generation of astronauts.
Everyone with the dream of one day looking down on our blue planet from a pitch-dark space can take a breath of relief. “You don’t have to be extremely well-trained.”, Linnarsson says, himself being involved in the selection of the astronauts. “You don’t have to be a physiological superhuman.” The general requirements are a high academic education, high capacity of multitasking, no predisposition for kidney stones and social competence. “On the contrary, when you don’t have gravity you don’t have any need of big muscles. From that perspective, women are more efficient as astronauts since they, in general, have a lower muscle mass, lower metabolic rate and lower oxygen needs. The big guys are not necessary in space. You don’t have to be strong, but you have to be healthy.”
Space has always been a mystery to mankind, inducing mixed feelings of love, wonder and fear. But our determination to explore the unknown is immense. It is the same determination that explores the life of cells, the systems of our body and the complexity of our brain. It is the same determination that put man on the moon and wants to put one on Mars. In space, the study of physiology not only teaches us new space-related things, but also provides a better understanding of how we function on Earth. Our biggest challenges are still ahead and we are still not ready to take the next step towards our red neighbour. Asking someone who practiced for more than 13 years before his first visit to space on how prepared you generally are prior to take-off, he answers: “You are actually not”.