how the space affects health and what to be prepared for

Cosmonaut training

The first cosmonauts in the Soviet Union and the United States were recruited from among military pilots and test pilots, but the astronauts’ need for various specialists grew, and soon doctors, engineers, scientists and representatives of other professions flew into space.

In Russia, historically there have been three departments for the training of cosmonauts, these are the departments of RGNII CTC, RSC Energia and SSC IBMP. As of May 31, 2008, there were 33 active cosmonauts and 7 cosmonaut candidates in Russia.

As of August 31, 2008, the NASA team consisted of 90 astronauts, in addition, 28 people were listed as astronaut managers.

According to the rules of the International Aviation Federation, “space” is considered a flight at an altitude of 100 km and above. According to the US Air Force classification, “space” is a flight exceeding 80 km 467 m (50 miles).

In Russia, “space” is called an orbital flight, that is, one in which the spacecraft must make at least one revolution around the Earth. Therefore, different sources give different numbers of astronauts. In addition, the US Air Force awards a badge – “astronaut wings” to pilots who have risen to an altitude of over 50 miles.

In addition to Russia and the United States, their teams and groups of cosmonauts have been formed in other countries of the world. Thus, according to the magazine “Cosmonautics News”, the ESA astronaut corps includes 8 astronauts, the Canadian Space Agency CSA’s national team of astronauts consisted of four astronauts at the beginning of June 2008. The astronaut corps of the Japan Aerospace Exploration Agency JAXA also includes 8 people.

The influence of space in the first seconds of being

From the first second of weightlessness, processes harmful to humans begin to occur in the body.

Motion sickness manifests itself in space form (analogous to seasickness), the interaction between sensory systems changes and sensory conflicts develop in the body, the function of the vestibular apparatus and the coordination of movements are disturbed, calcium begins to leak out of the bones, the mineral density in various parts of the skeleton decreases, redistribution of minerals occurs and the bones lose less than the lumbar vertebrae, pelvic bones and femur. The femoral neck is at greatest risk of fracture.

Changes in metabolism (negative nitrogen balance and the occurrence of catabolism processes; changes in the secretion of a number of hormones; progressive slowing of glucose utilization during sugar loading as the duration of flights increases) and the water-salt balance (decrease in the volume of plasma and intercellular fluid).

After establishing a negative balance of a number of ions in the blood, pathological forms of erythrocytes appear. In weightlessness, not only arterial, but also venous tone decreases, which is fraught with the development of varicose veins in the lower extremities in the early period after the flight.

Physiological effects

On November 2, 2017, researchers reported that significant changes in the position and structure of the brain were found in astronauts who flew into space, based on MRI studies. Astronauts who have taken longer space trips have been associated with more significant brain changes.

In October 2018, NASA-funded researchers found that long-term space travel, including trips to the planet Mars, can significantly damage astronauts’ gastrointestinal tissues. The research confirms previous work showing that such journeys can significantly damage astronauts’ brains and age them prematurely.

In March 2019, NASA reported that latent viruses in humans can be reactivated during space missions, possibly increasing the risk to astronauts on future space missions.

Space medicine is an evolving medical practice that studies the health of astronauts living in outer space. The main goal of this scientific study is to find out how well and how long humans can survive in extreme conditions in space and how quickly they can adapt to the Earth environment after returning from space.

Space medicine also strives to develop preventive and palliative measures to alleviate the suffering of living in an environment to which humans are poorly adapted.

  • Ascent and re-entry

During launch and reentry, space travelers can experience several times normal gravity. An untrained person can usually tolerate about 3 g, but can lose 4 to 6 g.

Overload in the vertical direction is more difficult to bear than a force perpendicular to the spine, because blood flows from the brain and eyes. First, a person experiences a temporary loss of vision and then, at higher g-forces, loses consciousness.

G-force training and a G-suit that compresses the body to keep more blood in the head can mitigate the effects. Most spacecraft are designed to keep g-forces within comfortable limits.

  • space environment

The environment in space is deadly without adequate protection: the greatest threat in the vacuum of space comes from lack of oxygen and pressure, although temperature and radiation are also dangerous. The consequences of space exposure can lead to ebullism, hypoxia, hypocapnia and decompression sickness.

In addition to this, there is also cellular mutation and destruction due to the high energy photons and subatomic particles present in the environment.

Decompression is a serious problem during extravehicular activities (spacewalks) for astronauts. Current EMU design addresses this and other issues and evolves over time.

The key issue was the competing interests of increasing astronaut mobility (which is reduced by high-pressure EMUs, similar to the difficulty of deforming an inflated balloon relative to a deflated balloon) and minimizing the risk of decompression.

Severe symptoms such as loss of tissue oxygen followed by circulatory failure and flaccid paralysis will occur within about 30 seconds.

The lungs also collapse in this process, but continue to release water vapor, which leads to cooling and ice formation in the airways. It is estimated that a person will have about 90 seconds to recompress, after which death may be inevitable.

In a vacuum, there is no medium to remove heat from a body by conduction or convection. Heat loss occurs due to radiation from a human temperature of 310 thousand to a temperature of 3 thousand in outer space.

This is a slow process, especially in a clothed person, so there is no risk of immediate freezing. Rapid evaporation of skin moisture in a vacuum can cause frostbite, especially in the mouth, but this is not a serious danger.

Without the protection of Earth’s atmosphere and magnetosphere, astronauts are exposed to high levels of radiation. A high level of radiation damage to lymphocytes, cells actively involved in maintaining the immune system; this damage contributes to the reduced immunity experienced by astronauts.

Radiation has also recently been linked to a higher incidence of cataracts in astronauts. In addition to protecting low Earth orbit, galactic cosmic rays pose additional challenges to human spaceflight, as the health threat from cosmic radiation increases the risk of cancer significantly after a decade or more of exposure.

A NASA-backed study reports that radiation can damage astronauts’ brains and accelerate the onset of Alzheimer’s. Lightning strikes (albeit rare) can deliver a lethal dose of radiation in minutes. It is believed that protective shields and protective drugs can eventually reduce the risks to an acceptable level.

Risk to humanity

With space and humanity’s survival comes a risk to humanity. A serious event in the future could lead to human extinction, which is also known as an existential risk.

Humanity’s long experience of surviving natural disasters suggests that, measured over several centuries, the existential risk of such dangers is quite small.

But scientists have run into a hurdle when it comes to studying human extinction, because the human race has never actually declined throughout history.

Although this does not mean that this will not happen in the future with such natural existential scenarios as: meteor impacts and large-scale volcanism; and artificial natural hybrid phenomena such as global warming and catastrophic climate change or even global nuclear war.

The most common problem that people experience during the first few hours of weightlessness is known as space adaptation syndrome, or SAS, commonly referred to as space sickness.

This is related to motion sickness and occurs when the vestibular system adapts to weightlessness. Symptoms of SAS include nausea and vomiting, dizziness, headache, lethargy and general malaise.

The first case of SAS was reported by the German cosmonaut Titov in 1961. Since then, about 45% of all people flying into space have suffered from this disease.

  • Deterioration of bones and muscles

Long-term weightlessness means loss of bone and muscle mass. Without the effects of gravity, skeletal muscles are no longer required to maintain posture, and the muscle groups used in weightless locomotion differ from those required for ground locomotion.

In weightless conditions, the astronauts put almost no strain on back muscles or leg muscles used to stand up. These muscles then begin to weaken and eventually become smaller.

Consequently, some muscles atrophy quickly, and without regular exercise, astronauts can lose up to 20% of their muscle mass in as little as 5-11 days. The types of muscle fibers that stand out in the muscles also change.

The slow-twitch endurance fibers used to maintain posture are replaced by fast-twitch fast-twitch fibers that are insufficient for hard work.

  • Fluid redistribution

In space, astronauts lose a volume of fluid, including up to 22% of their blood volume. Because it needs to pump less blood, the heart will atrophy. A weakened heart leads to low blood pressure and can cause problems with “orthostatic tolerance,” or the body’s ability to send enough oxygen to the brain without passing out or making the astronaut dizzy.

In 2013, NASA published a study that found changes in the eyes and vision of monkeys that flew into space for more than 6 months. Notable changes included flattening of the eyeball and retinal changes.

A space traveler’s vision can become blurry after being in space for too long. Another effect is known as the visual phenomenon of cosmic rays.

  • Intracranial pressure

Because weightlessness increases the amount of fluid in the upper body, astronauts experience increased intracranial pressure. This appears to increase pressure on the back of the eyeballs, affecting their shape and easily crushing the optic nerve.

This effect was seen in a 2012 study using MRI scans of astronauts returning to Earth after at least a month in space.

Such vision problems could become a major problem for future deep space missions, including a crewed mission to the planet Mars.

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