Cosmonaut training
The first cosmonauts in the USSR and the USA were recruited from among military pilots and
Historically, there were three detachments in Russiafor cosmonaut training, these are the units of the RGNII TsPK, 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 squad consisted of 90 astronauts, in addition, 28 people were listed as astronauts-managers.
According to the rules of the International Aeronautical Federation“Space” is considered to be a flight at an altitude of 100 km and above. According to the US Air Force classification, “space” flight is considered to be a flight whose altitude exceeds 80 km 467 m (50 miles).
In Russia, the "space" is called the orbitalflight, that is, one in which the spacecraft must make at least one turn around the Earth. Therefore, different sources give a different number of astronauts. In addition, the US Air Force awards the "Astronaut Wings" badge to pilots who have climbed over 50 miles.
In addition to Russia and the United States, their units and groupsastronauts formed in other countries of the world. Thus, according to the Novosti Kosmonavtiki magazine, there are 8 astronauts in the ESA astronaut corps, the national astronaut corps of the Canadian Space Agency CSA consisted of four astronauts at the beginning of June 2008. The astronaut squad of the Japan Aerospace Exploration Agency JAXA also includes 8 people.
Influence of space in the first seconds of finding
From the first second of weightlessness, processes harmful to humans begin to occur in the body.
Motion sickness manifests itself in a cosmic form(an analogue of seasickness), the interaction of sensory systems changes and sensory conflicts in the body develop, the functioning of the vestibular apparatus and coordination of movements are disrupted, calcium begins to wash out of the bones, the mineral density of various parts of the skeleton decreases, minerals are redistributed, and the bones of the legs lose less than the lumbar vertebrae, pelvic bones and femur. The femoral neck is most at risk for fracture.
Metabolism changes (negative nitrogenbalance and prevalence of catabolic processes; changes in the secretion of a number of hormones; progressive slowdown in glucose utilization under sugar load as flight duration increases) and water-salt balance (decrease in plasma and intercellular fluid volume).
After establishing the negative balance of the seriesions in the blood appear pathological forms of erythrocytes. In zero gravity, not only arterial, but also venous tone decreases, which is fraught with the development of varicose veins of the lower extremities in the early post-flight period.
Physiological effects
Since November 2, 2017, scientists have reported thatsignificant changes in the position and structure of the brain have been found in astronauts who have flown into space, based on MRI studies. Astronauts who made longer space travel were associated with more significant changes in the brain.
In October 2018, researchers funded byNASA found that long journeys into outer space, including travel to the planet Mars, can significantly damage the gastrointestinal tissues of astronauts. Research confirms earlier work, which showed that such travel can significantly damage the brains of astronauts and age them prematurely.
In March 2019, NASA reported that latent viruses in humans could be activated during space missions, possibly increasing the risk to astronauts on future deep space missions.
- Research
Space medicine is a developmentmedical practice studying the health of astronauts living in outer space. The main goal of this scientific research is to find out how well and for how long humans can survive in extreme conditions in space and how quickly they can adapt to the Earth's environment after returning from space.
Space medicine also seeks to develop preventive and palliative measures to alleviate the suffering caused by living in environments to which humans are ill-adapted.
- Rise and return to atmosphere
During takeoff and entry, spacetravelers may experience gravity several times greater than normal. An untrained person can usually tolerate about 3 g, but can lose 4 to 6 g.
Overload in the vertical direction is transferredmore difficult than a force perpendicular to the spine because blood flows from the brain and eyes. First, a person experiences temporary loss of vision, and then, at higher overloads, he loses consciousness.
Overload force training and G-suit thatconstricts the body to hold more blood in the head, may mitigate the effects. Most spacecraft are designed to keep the G-forces within comfortable limits.
- Space environment
The environment of space is deadly withoutadequate protection: The biggest threat in the vacuum of space comes from lack of oxygen and pressure, although temperature and radiation also pose dangers. The consequences of space exposure can lead to ebulism, hypoxia, hypocapnia and decompression sickness.
In addition to this, there are also cellular mutations and destruction due to high-energy photons and subatomic particles that are present in the environment.
Decompression is a serious problem during extravehicular activities (spacewalks) of astronauts. Current EMU designs take this and other issues into account and evolve over time.
Competing interests were a key issueincreasing astronaut mobility (which is reduced by high-pressure EMU, similar to the difficulty of deforming an inflated balloon relative to a deflated one) and minimizing the risk of decompression.
- Vacuum
Severe symptoms, such as loss of tissue oxygen followed by circulatory failure and flaccid paralysis, will appear in about 30 seconds.
The lungs also collapse in this process, butcontinue 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 re-compress, after which death may be inevitable.
In a vacuum there is no medium for removing heat from the bodythrough 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 with a clothed one.human, so there is no danger of immediate freezing. Rapid evaporative cooling of skin moisture in a vacuum can cause icing, especially in the mouth, but this is not a serious hazard.
- Radiation
Without protection of the Earth's atmosphere and magnetosphereastronauts are exposed to high levels of radiation. 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 morehigh 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 rays significantly increases the chances of cancer after a decade or more of exposure.
A NASA-supported study reportsthat radiation could harm the brains of astronauts and hasten the onset of Alzheimer's. Outbreaks (although rare) can produce a lethal dose of radiation in minutes. It is believed that protective shields and protective drugs can ultimately reduce the risks to an acceptable level.
Риск для человечества
With space and the survival of humanity comes risk to the human race. A severe event in the future could lead to human extinction, which is also known as existential risk.
Humanity's long track record ofin relation to survival from natural disasters suggests that, measured over several centuries, the existential risk posed by such hazards is quite small.
However, researchers have encountered a hurdle in studying human extinction because humanity has never actually declined throughout history.
Although this does not mean that this will not happen ina future with such natural existential scenarios as: impact of meteors and large-scale volcanism; and anthropogenic-natural hybrid phenomena such as global warming and catastrophic climate change or even global nuclear war.
- Motion sickness
The most common problem that people experience during the first hours of weightlessness is known as space adaptation syndrome, or SAS, commonly referred to as space sickness.
It is associated with motion sickness and occurs when the vestibular system adapts to weightlessness. Symptoms of SAS include nausea and vomiting, dizziness, headaches, lethargy and general malaise.
The first case was reported to SAS by cosmonaut German Titov in 1961. Since then, approximately 45% of all people who have flown into space have suffered from this disease.
- Deterioration of bones and muscles
Long-term weightlessness includes loss of bone andmuscle mass. Without the effects of gravity, skeletal muscles are no longer required to maintain posture, and the muscle groups used when moving in zero gravity are different from those required for locomotion on land.
In zero-gravity conditions, the astronauts hardly used their back muscles or the leg muscles used to stand up. These muscles then begin to weaken and eventually become smaller.
Consequently, some muscles quicklyatrophy, and without regular exercise, astronauts can lose up to 20% of their muscle mass in just 5–11 days. The types of muscle fibers projecting into the muscles also change.
The slow twitch fibers of endurance used to maintain posture are being replaced by fast twitch fast twitch fibers, which are not sufficient for any kind of hard work.
- Redistribution of fluid
In space, astronauts lose fluid volumeincluding up to 22% of your blood volume. Because it has less blood to pump, the heart atrophies. 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 the astronaut fainting or feeling dizzy.
- Vision
In 2013, NASA published a study thatduring which changes were discovered in the eyes and vision of monkeys that flew into space for more than 6 months. Noticeable changes included flattening of the eyeball and changes to the retina.
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
As weightlessness increases the amountfluids in the upper body, astronauts experience increased intracranial pressure. This appears to increase pressure on the dorsum of the eyeballs, affecting their shape and slightly crushing the optic nerve.
This effect was seen in a 2012 study using MRI scans of astronauts who returned to Earth after at least one month in space.
Such vision problems could pose a major concern for future deep space missions, including a crewed mission to the planet Mars.
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