Outer space is a hostile environment. In it, cosmic radiation and charged particles emitted by the Sun reach us, as they are not protected by the Earth’s magnetic field . In addition, the human body does not take particularly well to remain in a zero gravity environment for long periods of time . Between muscle atrophy and bone loss, astronauts require long rehabilitation times once they return to Earth after a long stay on the International Space Station.
This is why when we consider sending humans to Mars we must consider what effects the more than 7 months that the outward journey lasts will have on the body of the astronaut team. More than 20 years of continuous occupation of the ISS have taken us a long way, and we now have a much better understanding of the effects that prolonged stays in space have on the human body. But even so, in this environment we still have the protection of the Earth’s magnetic field.
On many occasions, when astronauts land after more than 6 months up there, they can barely walk or stand for more than a few minutes , because their body has lost the ability to withstand Earth’s gravity without problems. When the first humans visit the red planet, they could face similar problems, with the small advantage that Martian gravity is a third of that of Earth , but with the great disadvantage that they do not have a medical team to attend to them after arrival. Therefore, it seems vital to find ways to minimize the impact that this trip will have on the body of the astronauts, but also to be able to prevent which of them will be able to carry it better, due to their health and physical constitution.
With this objective, a team of researchers from the Australian National University has developed a mathematical model to predict, given certain parameters, who would be prepared to carry out the necessary tasks after landing. As indicated by this team, the main concerns, at least as far as physical health is concerned, during a trip of this type, would be the prolonged absence of gravity and exposure to cosmic radiation . Especially the first would be worrying in the short term, because the response given by the body of each astronaut after landing will depend on the start of the mission on the right foot.
This prolonged absence of gravity would not only affect the bones and muscles, causing them to lose mass and strength, but it would also affect the circulatory system. By not having to fight Earth’s gravity 24 hours a day, your blood capillaries could undergo changes and your heart could lose shape.
The ANU team warns that with the growing number of private companies in the aerospace sector , such as SpaceX or Blue Origin, space will soon become accessible to people rich enough to afford a trip , but perhaps not healthy enough. to resist it . Our body and that of the rest of the living beings that inhabit the Earth, has evolved to adapt to the presence of terrestrial gravity and takes it into account in its operation. That is why it is natural for us to swallow water or food while upright, but not so much if we lie down and why sometimes we notice our feet swollen (with blood) at the end of the day or we feel dizzy if we adopt a position where the head is above under our legs.
In the absence of gravity, the circulatory system sends too much blood to the upper body and this makes our internal system think we have too much fluid . As a consequence, we visit the bathroom more often and drink less, becoming dehydrated in the process.
The developed mathematical model tries to predict if a specific astronaut, given his state of health, will be able to survive the trip to Mars and not suffer from dizziness when he reaches the red planet. This mathematical model has been created from data collected over more than 50 years from hundreds of astronauts , who have visited the International Space Station, but also the Moon during NASA’s Apollo missions.
This model right now is calibrated for middle-aged individuals, between 30 and 60 years old and in good physical shape , since that is the demographic of an average astronaut, however they want to extend it so that it is able to predict the ability of any person to travel to Mars and be operational upon arrival, regardless of the age or physical condition from which it departed. In other words, they want to extend their mathematical model so that it can be used in any “normal and ordinary” person, people like you and me who probably will never visit Mars, but who do not intend to stop dreaming for that.
Lex M. van Loon et al, 2022, Computational modeling of orthostatic intolerance for travel to Mars, npj Microgravity, DOI: 10.1038/s41526-022-00219-2