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Nasa astronaut Megan McArthur returns from a SpaceX flight on November 8th
Photo: Aubrey Gemignani / imago images / ZUMA Wire
Astronauts have to be physically fit and yet as petite as possible - in order to be able to move around easily in the confines of the space station ISS.
According to the knowledge of space medicine, it can still get a bit tighter in space: because astronauts get taller in weightlessness when they fly into space.
"The intervertebral discs expand and you grow an average of five and a half centimeters in length in the first 24 hours," said space doctor Bergita Ganse of the dpa news agency in Homburg, Saarland.
But: "When you come back to earth, you shrink back to your original size," said the professor who teaches at Saarland University - and who closely follows the six-month mission of the Saarland astronaut Matthias Maurer (51) on the International Space Station ISS .
»Fluid shift«: thick head and skinny legs
Another short-term change that space tourists also experienced is a fluid shift in the body towards the upper body and head. "This means that you pee out 1.5 liters of water in the first 24 hours - and that you get a very fat face and very thin legs," said Ganse, who previously worked for the German Aerospace Center (DLR) worked in Cologne. Explanation: Normally, gravity pulls the water into your legs, but that doesn't exist in weightlessness.
In the long term, the muscles degrade because you don't use them in a weightless space.
"You only have to nudge a heavy object to make it move." The heart muscle is also getting smaller.
On the ISS, therefore, two and a half hours of training are scheduled for the astronauts every day: with a bicycle ergometer - with shoes clamped in clipless pedals - a strength training device and a treadmill on which you can fasten yourself with rubber bands.
Fitness challenge on the way to Mars
In future missions to Mars, for example, these devices could not be taken with you due to a lack of space: Therefore, other methods are being sought to prevent muscle breakdown. Ganse is researching electrical stimulation with an international group. "If you also stimulate the muscles with electricity, you may not need as much training." And less space. 16 astronauts will be involved in the experiment on the ISS over the next few years.
A Mars mission is expected to last around two and a half years, said Ganse. The outward flight takes at least nine months, as does the return flight. And then it still takes time on site. With this duration there are new questions for space medicine. In an emergency, you can fly back to Earth from the ISS in six to eight hours. But when it comes to Mars, you have to act locally - which is why there is a discussion about which medical devices should be on board, said Ganse, who is on the board of the Space Surgery Association.
When it comes to drugs, attempts are being made to develop a device that can be used to "print" drugs.
That means that you take chemicals with you that you can use to "build drugs on the fly," said the expert.
“It's not technically easy.” The advantage of this is that you don't have to decide before the flight how much of which medication to take with you.
Hope space tourism
Such a device for printing drugs could also be of great use on earth, for example in rural areas or in developing countries, says Ganse.
Likewise, electrical stimulation to build muscle may be a breakthrough for the elderly on earth.
"If we can gain new knowledge and thereby help people in old age, then a lot will be gained."
Space medicine has not yet developed that far, because one relies on knowledge from people who fly into space.
And there the number and experiments are limited.
The doctor puts hope in space tourism.
“For the first time in human history, elderly and sick people are flying into space.
So far there is no data at all on this. ”It would therefore be important to make this data available to science.
The physician is convinced that astronaut Maurer will come back to earth "in good condition".
He works out a lot so he won't have any problems with muscle loss.
They assume that after two to three weeks on earth he will be completely fit again.
"And he'll get real sore muscles when he uses his muscles again," she said.
Since March, Ganse has headed the chair for innovative implant development at Saarland University.
mrc / dpa