Kennedy Space Center (United States) (AFP)
From muscle wasting to radiation exposure through the psychological impact of confinement, space travel puts a strain on the health of the lucky ones.
Adrianos Golemis, flight doctor for the European Space Agency, is responsible for watching over French astronaut Thomas Pesquet during the SpaceX Crew-2 mission which is to take him to the International Space Station (ISS).
Question: What are the main health issues in space?
Answer: "If we are talking about low earth orbit where the ISS is located, gravity is almost zero, which has consequences for bones and muscles.
Radiation is a major problem, because here at ground level we are protected by the magnetosphere (terrestrial magnetic field) and by the atmosphere, but the further we go, the more this protection disappears.
And of course there are things that we are just starting to understand: for example eye conditions or venous thrombosis (blood clots) that some healthy astronauts develop. "
Q: What is the state of current scientific knowledge on the exposure of the human body to these radiations?
A: "You could complete two or three six-month missions on the ISS probably without noticing any noticeable effect on your health.
Our goal is to ensure that the risk of developing cancer is no 3% greater than that of someone exactly like you who has never been in space flight. "
Q: Does weightlessness have other effects?
A: "We have adapted to life with earthly gravity (1 G). If this is gone, the veins in your feet will continue to send blood towards your head as if you were still there. with 1 G, so you have excess blood in the upper part of your body.
Sometimes you can see that the astronauts have a really puffy face at the start of the mission.
Eventually the blood system adapts and the body gets used to the less blood volume.
So before they leave the ISS, we ask the astronauts to drink a lot and eat a lot of salt. "
Q: Astronauts are vaccinated against Covid-19, should we continue to test them?
A: "They are in quarantine but we have scheduled two PCR tests, to be 100% sure that they are not even carriers (of the coronavirus).
When we are without gravity, the immune system is less efficient.
People can develop infections that they would never otherwise have, simply from the germs that our bodies naturally carry. "
Q: The crew spend two hours every day on sports equipment in order to stay in shape, do you keep in touch with them too?
A: “We have a routine fifteen minute video call once a week.
At the start of the mission, we mainly look for signs of space sickness, when we go from 1 G to zero G. Your brain has a little trouble getting used to, there is a sensory conflict between the ear internal and what your eyes perceive, and it can cause nausea.
Later in the mission, we focus on other things, especially on the psychological level or on cognitive performance.
When you stay in an environment like the ISS you are really in a very small place, there are no new stimuli and it has a psychological impact.
It is not so easy to concentrate or memorize information. "
Q: Other than a full medicine cabinet, what kind of medical equipment does the ISS have?
A: "For example, we can analyze the hematocrit (red blood cells) and deduce from it if the astronauts are hydrated enough, what changes are taking place in their blood system.
Two years ago, we observed signs of thrombosis.
No one expected this in healthy individuals, and it shed new light on how the body works on our planet.
We now have ultrasound equipment, and if someone has symptoms such as pain or swelling, another member of the group can perform an ultrasound to assess whether it is a clinical case of thrombosis.
In a case where the life or well-being of an astronaut was really in danger, we would decide to evacuate him.
Fortunately, in the 21 years that the ISS has been in space, this has never happened. "
© 2021 AFP