Museum Scientific Consultant "Experimentanium" and physiologist Anton Zakharov tells what happens to the human body while he is flying into space and while he is there. The online publication M24.ru provides the full text version of the lecture.

We will talk about what happens to a person on a space station a little later, but for now we need to deal with the difficulties that await a person when taking off into space. The first difficulty he faces is what? I think you can guess?

- Weightlessness.

No, weightlessness will come a little later.

- Overload.

Overload, absolutely correct. Here is a small sign, a sign of the sensations that a person experiences when he experiences overload. In general, what is overload, where does it come from? Do you think there are any ideas? Please.

- The plane or space station begins to rise, while the person begins to deviate in the other direction, an overload occurs.

Why is it called overload?

- Probably because the person feels uncomfortable.

In fact, you and I are simply very accustomed to living with a load. When you and I are, as we are now - you are sitting, I am standing - on our planet Earth, we are attracted to the Earth, and our blood is attracted to the Earth stronger than all other parts of our body, because it is liquid. It's as if she's heading towards the Earth. And the rest of our body is more solid, so they are a little less attracted to the Earth, but their shape is more constant. And we are very well adapted to this load, and when we lose this load, a not very pleasant sensation will occur, which I will talk about later.

But before getting into weightlessness, where there is no such load, a person experiences overload, that is, the excessive effect of gravity. With a double overload - an overload of 2 g - the person's body becomes heavy, the face sags a little, it is difficult to stand up, of course, you need to lift not the 50-60-70 kg that you usually weigh, but twice as much. With a threefold overload, it is no longer possible for a person to stand, and the person’s digital vision first turns off, because the cells that are responsible for digital vision consume a lot of energy. At 4.5 g, vision completely turns off, our retina no longer has enough blood, and it is no longer possible to raise an arm or leg. And at 12 g, most people pass out. Everything I am saying now concerns not instantaneous overloads, but those that last for some time, at least 10-20-30 seconds; instantaneous overloads are stronger. Do you think such overloads can be encountered in everyday life without going into space?

Can an overload of 4.5 g be experienced without taking off into space? In fact, it's usually around 1.5, but if you go on rides, just 3-4 g is quite possible to experience. And so, it is clear that a person standing motionless experiences 1 g; on an airplane - about 1.5; a parachutist who lands is about 2 g; at the moment the parachute opens, he experiences 10 g for a very short time, that is, almost on the verge of losing consciousness. At the same time, cosmonauts who fly now experience less - 3-4 g, they have these 8-12 - very strong overloads - no, only cosmonauts experienced them when they were just building spaceships, then it was 7-8 g, this was problem. Now everything is done so that it is easier to take off.

In fact, military pilots often experience the most intense stress. At the moment of performing some aerobatics, it’s quite possible to feel 12 g, but for a short enough time, so they don’t lose consciousness - this is one thing, but two - they are very prepared, so it’s easier for them to cope. The maximum overload acceptable for health, even short-term, is approximately 25 g. If the overload is greater, even short-term, then the probability that a person will break his spine begins to approach 90%, and this, naturally, is not very good.

We talked about ordinary overloads, the so-called positive overloads. We found out that antigravity does not exist. Do you think there can be negative overloads? (But overload and gravity are slightly different concepts) And, indeed, there are negative overloads, if you just stand on your head, you will experience a negative overload of -1 g, because the blood that usually rushes to the legs and the parts of the body that usually press on each other in one direction, will begin to press on each other in the other direction, and the blood will begin to rush to the head. This is quite a negative overload and, naturally, large negative overloads are also harmful to health, and they can also be experienced without flying into any space. For example, they are experienced by bungee jumpers - what is called bungee jumping in English.

In fact, this bungee jumping... Firstly, I’m scared to even look at photographs, and secondly, it’s very interesting ritual. Does anyone know where it came from? The fact is that the Indians of the Vanuatu tribe South America This is how boys were initiated into men. They climbed tall tree, they took some kind of strong vine, tied it to his feet, and the teenager had to jump with this vine of visas, not reaching the ground a meter or two. And if he calmly stood it, he became a man. When Oxford students learned about this in the 70s of the twentieth century, they were wildly delighted and decided that such a tradition should be repeated. But they decided that the first jump should be filled with solemnity, and they dressed up in tailcoats. Nowadays bungee jumpers are informal people, but the first jumpers jumped in suits, it was quite beautiful.

We talked to you about overloads; this is not the only problem that astronauts experience. The astronauts took off, coped with the overloads, ascended into space, and immediately the first joys and the first problems awaited them.

Well, joy, of course, when a person rises into space, his pants are full, that’s understandable. And astronauts, like small children, have a higher “happiness hormone” in their blood than do ordinary people. And you can, in principle, understand them; a lot of cool things are happening there. Let's watch a video from the ISS. Basically, people have fun as best they can, of course. It is not necessary to carry things with your hands; you can carry them with your feet. Movements must be very precisely calculated, must be very careful. This is how astronauts actually don’t wash their hands, this was filmed specifically for the video, for the sake of these 10 beautiful seconds, the cosmonauts will then spend a lot of effort collecting these droplets one by one. It just seems - wow, how cool they scattered, but they really scattered, now they all need to be collected, the problem is quite serious.

So, we have roughly seen how astronauts live in space, now let’s think about what problems await them there. The first problem is related to the fact that a person does not experience gravity there. Even his balance organs do not experience gravity. Does anyone know where our balance organs are located?

- In the head, cerebellum?

In the ear. No, the cerebellum is the brain center that provides coordination of balance, but it is not the sensitive part, and the sensitive part is in our ear. The beautiful pebbles that are depicted here are otolith crystals, these are pebbles that are located in our vestibular apparatus, its sac, and when we turn our heads from side to side, they roll inside our vestibular apparatus, so we understand that our head is turned relative to the rest of the body. These crystals are in these bags. What happens in space, in space one happens simple thing, these pebbles begin, like everything steel, to float inside the vestibular apparatus - a person experiences a malfunction. On the one hand, his eyes tell him that he is still standing upright, everything is fine, but on the other hand, his balance organs say: I don’t understand what happened, I’m wobbling in all directions, I don’t know what to do. There is a manifestation similar to space sickness - seasickness. Then the same thing happens, the vestibular apparatus sways in different directions, but the eyes sway not so much, and the body malfunctions, and the body begins to do what?

- Vomit.

He begins to feel sick, and in space he begins to feel sick in the same way, but since in space this restructuring occurs much more sharply, almost all astronauts experience space sickness. Not everyone, however, feels sick, but those who feel sick are a dangerous thing. Because people usually experience attacks of space sickness at the moment when they are already docked at the space station and still in their space suits. They begin to make their first movements when entering the space station, that is, they are in closed spacesuits and, laughter and laughter, but this is one of the serious reasons for the death of astronauts, simply because the spacesuit is closed, and it is impossible to fly without a spacesuit. Why, I’ll tell you about this a little later.

Let's go further, another problem that awaits people in space is a decrease in the number of blood cells. There are various reasons for this, one of the reasons is this: in space, bone tissue decreases, and inside the bone tissue, blood cells are formed. Therefore, if there are fewer seeds, then there are fewer cells. In general, a rather unpleasant thing, especially unpleasant when the astronaut returns to Earth, and he needs to go through a period of adaptation back to conditions on Earth. He also experiences a severe lack of oxygen precisely because he lacks these blood cells that carry oxygen. Actually, more about the bones. Why do bones break down in space, do you know? Any ideas?

- There is no load.

There is no load, it’s absolutely true that in order for our bones to work normally, they must constantly receive some kind of load, you and I must constantly work. But we remember that working in space is not easy: there is no need, there is no opportunity. Since there is nothing weighing there, no matter what you do, you waste a lot less effort. And even though astronauts train all the time, they still cannot experience the same level of physical activity as on Earth. Therefore, after 3-4 flights, problems with bones begin, which, in particular, lead to osteoporosis, when bone tissue is destroyed.

Another problem is again with blood. I said that we are very well adapted to the load on Earth. How are we adapted? We have an excess amount of blood; each adult has approximately 5 liters of blood. This is more than we need. Why do we need this excess? Because we are erect, and most of the blood remains in our legs, at the bottom of our body, and not everything reaches the head, so we need to store some excess so that there is enough blood for the head. But in space, the force of gravity immediately disappears, and therefore this excess blood, which was in the legs, begins to urgently move somewhere throughout the body. In particular, it gets into a person’s head and brain, resulting in strokes, micro-strokes, because too much blood gets in and the vessels simply burst. As a result of this, in the first week, astronauts especially often run to the toilet, just as they are losing excess fluid; they lose about 20% of excess fluid during the first week of being in orbit.

The muscles also do not experience stress. Regardless of the size of the cargo, regardless of how much it weighs on Earth, there will be no difficulty in transferring it in space. Therefore, as I have already said, astronauts must train in space. The next video is about this. Naturally, there is no point in lifting weights in space; you can try running. Indeed, a man is running, only, pay attention, he is tied to a treadmill, because if he were not tied to a treadmill, he would simply fly away. Again, you can't lift weights, but you can bend springs, and astronauts spend at least 4 hours a day doing physical exercise. Cosmonauts, as you know, are the most prepared people, the most physically strong and resilient. And all the same, when they return from space, firstly, they never again reach the shape they had before the first flight, and secondly, even an approximate recovery from these loads takes about the same time as an astronaut was in orbit. That is, if he was there for six months, he will recover for six months; for the first few weeks they cannot even walk. That is, their leg muscles practically atrophied; they did not use them for six months.

Let's move on, another problem related to what an astronaut must breathe in space. The problem is two-sided: first of all, you need to lift air or oxygen into orbit. What do you think is better to lift - air or oxygen - than what we breathe?

- Oxygen.

Oxygen, the Americans also thought that it was better to lift pure oxygen into orbit, albeit a little rarefied. Although, in fact, pure oxygen is a rather scary thing. Firstly, it is dangerous for the body, it is poison - in large quantities, and secondly, it explodes very well. For the first few years, rockets filled with pure oxygen took off normally, and then at some point one spark ran, and from spaceship no stone was left unturned. After that we decided to do the same as I did Soviet Union, - just cylinders with liquid air. This is a difficult option, it is expensive, but safe.

There is a second problem: when we breathe, we release carbon dioxide. If there is too much carbon dioxide, first a headache begins, drowsiness appears, and at some point a person may lose consciousness and die from the excess carbon dioxide. We on Earth emit carbon dioxide, and plants absorb it; in space, even if you take one or two plants with you, they will not cope with this work, and you cannot take many plants with you, because they are heavy and take up a lot of space. How to get rid of carbon dioxide? There is one special Chemical substance, which can absorb excess carbon dioxide, is called lithium hydroxide, it is transported into space, it just absorbs excess carbon dioxide. There is one very interesting, heroic story associated with this substance, the story of the Apollo 13 spacecraft, I think adults remember this story.

Have your children ever heard of Apollo 13? Have you heard that they even made a movie about what happened to this ship? He had a very unsuccessful flight, there were a lot of different things, we are interested in what happened to the lithium hydroxide. The story is this: Apollo 13, not for the first time, not for the second time, flew to the Moon to explore the Moon. Three people were flying there, they had their own spaceship and a special capsule that was supposed to land on the Moon, and two people who were supposed to go out on the Moon, do something there, and then return on the capsule back and fly to Earth. But somewhere on the 3rd day of the flight, an explosion suddenly occurred, and part of the main ship was turned around, including damaging the life support system. In principle, this is not such a terrible problem, because the boat on which it was necessary to fly up to the Moon was intact, and it was quite possible to return to Earth on it. But there was a completely idiotic problem: the canisters with lithium hydroxide that were stored on the boat and the canisters with lithium hydroxide that were stored on the ship were different, they simply had different inlet holes. And all the American engineers who were associated with the project, and many engineers around the world, did for about a day what people usually do in the “Crazy Hands” program. They figured out how to use glue, scraps of newspaper, paper clips, and whatever was found on the ship to convert one exit into another so that people could fly back to Earth. They succeeded, thank God, and this ship (while it was landing, there were also many different problems), thank God, landed normally.

We found out that people in space have problems when they are awake: bad with blood, bad with muscles, bad with bones, and so on and so forth. Sleeping in space is also bad. There are two reasons: the first reason is that no one turns off the lights on the space station, it must work all the time, some experiments are being carried out there all the time. The work is very intense, so the cosmonauts sleep on shifts: first some, then others. It’s hard, if you sleep like this for a day, two, three, then it’s okay, but if you sleep like this for two or three weeks or a month, then changes begin in the body, and this is harmful. This is harmful for us too, because now many people in large cities live in the wrong light conditions, because of this we suffer and don’t even notice it. Another problem is related to the fact that since there is no attraction, a person cannot rely on anything, and this is a very important feeling, as psychologists have found out. In order to fall asleep, a person needs to lean against something and feel confident. Therefore, astronauts put on special bandages under their knees and put on special blindfolds to create at least some kind of imitation of what they are being pulled somewhere. It doesn't turn out very well, but it works. There is a third problem, related to carbon dioxide: while we are sleeping, we breathe and emit carbon dioxide, we do not move, and carbon dioxide accumulates on the surface of our face. On Earth this is not scary, why?

- He moves all the time.

He really moves all the time, but why? Because there is a slight breeze, but that’s not the point. When we exhale carbon dioxide, we exhale it warm, and warm gas will rise to the top because it is lighter than cold gas. In space, neither warm nor cold gas has weight, so exhaled gas will accumulate above a person, and he will simply sleep in this cloud if nothing is done about it. But they are actually doing something about this - and in space there are very powerful ventilation systems that disperse carbon dioxide so that we can sleep peacefully. And these same ventilation systems filter the air from various infections and pathogens. Now they have learned to cope with this more or less, but at first the astronauts got sick a lot, because the quarantine was not strict enough, and it is much easier to get infected with something in space. Because when we sneeze on Earth, what we sneezed falls to the ground and remains in some dust; we do not inhale it directly. And if an astronaut sneezes, then everything that he sneezed remains in the air, so the likelihood of catching this infection is much higher, so everything is filtered there. There really is a lot of dust among the astronauts, they still sneeze a lot, but they get sick less because the quarantine is stricter.

Another problem that awaits astronauts is cosmic radiation. We on Earth are protected from cosmic radiation by an atmosphere that does not allow radiation to pass through; in particular, we are well protected from it by the ozone layer. But in space there is no ozone layer, and astronauts experience increased radiation. This is dangerous, and they were afraid of it for a very long time until they checked how much radiation a person experiences there. He experiences about the same amount as the inhabitants of those places that are located in granite rocks, for example, experience. Granite rocks also emit a little radiation, about the same amount an astronaut receives. That is, residents of, say, Cornwall (this is in England), consider astronauts in this regard, even receive a little more radiation. And pilots and flight attendants of supersonic aircraft (Concorde, for example) who fly at high altitudes receive a lot of radiation.

But we hope that one day a person will not only fly space stations, and will reach Mars and other planets. And in these cases, a threat awaits us, because usually space stations fly around the Earth - where the radiation field is not very strong. But around the Earth there are two “donuts” of powerful radiation fields through which you need to fly to get to the Moon, Mars, and other planets. And the radiation there is very strong, and one of the problems of sending to Mars now is exposure to radiation for several months. People may get there, but they will get there very sick - naturally, no one wants this. Therefore, they are now figuring out how to make both a light spacesuit and a light skin for a spacecraft, which would also protect against radiation. Because in principle it’s not difficult to protect yourself from radiation, you can line a ship with lead and okay – we’re protected from radiation, but lead is very heavy.

We talked about the disadvantages, disadvantages, disadvantages. But there are not only disadvantages when flying into space. When we fly into space (this is not really a big plus, it’s just very nice) we become a little taller. Under the influence of gravity, while we walk somewhere all day, our vertebrae press on each other, and most importantly, they put pressure on intervertebral discs. They “flatten” a little during the day, so a person is several centimeters taller in the morning than in the evening. If you haven't tried it, you can check it at home. Why is it always advised to measure height at the same time, because it changes during the day. Well, in space gravity doesn’t work, so astronauts grow a little tall, sometimes even too tall. One cosmonaut grew by as much as 7 centimeters, he was very happy, he was already many years old at that moment, there was only one problem - the spacesuit did not grow, it was quite cramped. Now all the spacesuits are made - 10 centimeters are left in case the astronaut grows up.

An interesting thing: in space, it turns out, regeneration processes go faster, wounds heal faster, and even entire parts of the body can be restored. Now there will be a video with a snail. Here, of course, the shooting is accelerated; in fact, it grew for about two weeks. On the ground, snails also regenerate, but worse. Why this happens is unclear. Why am I saying all this? I said already at the beginning: before our eyes, in the near future, the number of people who will fly into space will grow, and grow, and grow. Perhaps soon this will not be a topic for a popular science lecture, but a standard lesson at school: you will need to know what happens to a person when he simply decides to go on an excursion into space. I really believe that this will happen soon, and I hope that you believe too. If you have any questions, please ask.

- Tell me, if there were overloads, a blackout, how quickly does a person recover and regain consciousness?

When consciousness turns off, the system is the same as when a person faints. Some people get up right away, some not right away, some have a strong effect, others less. In general, this is, of course, harmful. A person loses consciousness because there is not enough oxygen entering the blood, which means not enough oxygen is reaching the brain. As a result, some brain cells may begin to die, some more actively, some less actively.

Tambov regional state educational institution

General education boarding school with initial flight training

named after M. M. Raskova

Essay

"Overload in aviation"

Completed by: student of 103 platoon

Zotov Vadim

Head: Pelivan V.S.

Tambov 2006

1. Introduction.

2. Body weight.

3. Overload.

4. Overloads when performing aerobatic maneuvers.

5. Overload restrictions. Weightlessness.

6. Conclusion.

OVERLOAD IN AVIATION

1. Introduction.

Gravitational forces are, obviously, the first forces that we become familiar with from childhood. In physics they are often called gravitational (from the Latin - gravity).

The importance of gravitational forces in nature is enormous. They play a primary role in the formation of planets, in the distribution of matter in the depths of celestial bodies, determine the movement of stars, planetary systems and planets, and maintain the atmosphere around the planets. Without gravitational forces, life and the very existence of the universe, and therefore our Earth, would be impossible.

When constructing buildings and canals, penetrating into the depths of the Earth or into outer space, constructing a ship or a walking excavator, achieving results in almost any sport, a person deals with the force of gravity everywhere.

Great and mysterious forces gravity has been the subject of reflection by outstanding minds of mankind: from Plato and Aristotle to ancient world to the scientists of the Renaissance - Leonardo da Vinci, Copernicus, Galileo, Kepler, from Hooke and Newton to our contemporary Einstein.

When considering gravitational forces, various concepts are used, including gravity, gravity, weight.

2. Body weight.

Weight is the force with which, due to gravity, the body presses on a support or pulls on a suspension.

In aerodynamics, body weight is understood as a slightly different quantity.

During flight, an airplane is affected by aerodynamic forces (lift and drag), the thrust force of the propulsion system and the force of gravity, which is called weight and denoted G.

where m is mass aircraft, g – free fall acceleration.

Weight is one of the most complex forces in nature. You know that weight is not a constant quantity; it changes depending on the nature of the body’s movement.

If a body moves without acceleration, then the weight of the body is equal to the force of gravity and is determined by the formula P = mg.

If a body moves with upward acceleration, i.e., with acceleration opposite to the acceleration of gravity (a↓g), then the weight of the body increases, determined by the formula P = m(g+a) and an overload occurs.

If a body moves with downward acceleration, i.e., with acceleration co-directed with the acceleration of gravity (a ↓↓g), then the weight of the body is determined by the formula P = m(g-a), and in this case several options are possible:

if |a|<|g|, то вес тела уменьшается (становится меньше силы тяжести), и возникает состояние частичной невесомости;

if |a|=|g|, then the weight of the body is 0, a state of complete weightlessness arises (i.e., the body falls freely);

if |a|>|g|, then the body weight becomes negative and a negative overload occurs.

3. Overload.

Overload is the ratio of the sum of all forces, except the weight force, acting on the aircraft to the weight of the aircraft, and is determined by the formula:

where P is the engine thrust, R is the total aerodynamic force.

The arrows above the symbols in the formula indicate that the direction of action of the forces is taken into account, so the forces cannot be added algebraically.

For example, if the aerodynamic force R and engine thrust P lie in the symmetry plane, then their sum R+P is determined as shown in Figure 4.14.

In most cases, they do not use the total overload n, but its projections on the axes of the velocity coordinate system - n x , n y , nz as shown in Figure 4.15.

There are three types of overload: normal, longitudinal and lateral.

Normal overload n y is determined primarily by the lifting force and is determined by the formula:

where Y is the lifting force.

At a given flight speed and altitude, the normal overload can be changed by changing the angle of attack. As shown in the figure, with decreasing flight speed, the maximum normal overloads increase, and with increasing altitude, they decrease. At a negative angle of attack, negative overloads occur.

Longitudinal overload n x is determined by the ratio of the difference between engine thrust (P) and drag (Q) to the weight of the aircraft:

n x = (P-Q) / G.

Longitudinal overload is positive if the thrust is greater than the drag, and negative if the thrust is less than the drag or if there is no thrust at all.

Thus, the sign of the longitudinal overload depends on the ratio of the engine thrust and the aircraft's drag.

With increasing flight altitude, positive longitudinal overloads n x decrease, since the redundancy of the body decreases. The dependence of longitudinal overload on altitude and flight speed is shown in the figure.

Lateral overload n z occurs when the air flow is asymmetrical around the aircraft. This is observed in the presence of slip, or when the rudder is deflected.

4. Overloads when performing aerobatic maneuvers.

Let's consider what overloads occur when performing aerobatic maneuvers.

On airplanes in different aerobatic maneuvers, overload acts differently.

For example, on the L-39 aircraft, when performing a half-loop, it is necessary to maintain optimal changes in overload.

A half-loop is an aerobatics maneuver during which the aircraft describes the ascending part of a Nesterov loop, followed by a rotation relative to the longitudinal axis by 180 0 and a horizontal position.

flight in the direction opposite to the input.

When performing this figure, you can mark several reference points:

1. Half-loop entry.

2. Pitch angle 50 0 – 60 0. Overload in this

point 4.5 – 5 units.

3. Pitch angle 90 0 . Overload 3.5 – 4 units.

4. Beginning of insertion into the half-barrel. Overload

approximately equal to 1 unit.

5. Output from a half-barrel.

When the overload is greater than optimal, the frontal resistance sharply increases and the speed quickly drops; the aircraft may enter the mode of shaking and stalling. When the overload is less than optimal, the time it takes to complete the figure increases and the speed at the top point also becomes less specified.

Let's consider another aerobatics maneuver - a coup.

A rollover is an aerobatics maneuver during which the aircraft turns relative to the longitudinal plane of the axis by 180 0, followed by movement along a downward trajectory in the vertical plane and launches into horizontal flight in the direction opposite to the input.

When performing a rollover on the L-39, in the first half of the trajectory, the component of the weight force (Gcosθ) contributes to the curvature of the trajectory, therefore, in this section, the normal overload value of 2 - 3 units is quite small. In the second half, the same force prevents the curvature of the trajectory, therefore, to bring the aircraft out of a dive, a large overload of 3.5 - 4.5 units is required. During a rollover, the aircraft freezes; the pilot eliminates the occurrence of negative overloads in the “wheels up” position by taking control of the control stick, increases the overload to the permissible level, and creates the necessary angular rotation.

On the Yak-52, for example, when performing a dive, a negative overload appears when entering the dive. When recovering from a dive, the loss of altitude is determined by the speed, angle of the dive and the overload created by the pilot.

When exiting the Gorki turn, in order to avoid the occurrence of large negative overloads, the pilot makes the exit by smoothly moving the control stick away from himself.

"Dive" "Slide"

Another exciting aerobatics maneuver is the Nesterov loop.

The Nesterov loop is an aerobatic maneuver in which the aircraft describes a trajectory in the vertical plane located above the entry point.

When performing the Nesterov loop on the Yak-52, the pilot must monitor the creation of angular velocity as the overload increases. It is necessary to create the angular speed of rotation in such a way that at a pitching angle of 40 0 ​​- 50 0 the overload is equal to 4 - 4.5 units. When moving the aircraft out of a loop, the pilot must monitor the rate at which the overload increases.

On March 22, 1995, cosmonaut Valery Polyakov returned from space after 438 days of flight. This duration record has not yet been broken. It became possible as a result of ongoing research in orbit on the influence of space factors on the human body.

1. Overloads during take-off and landing

Perhaps it was Polyakov who, more than anyone else, was prepared to stay in orbit for a year and a half. And not because he supposedly has phenomenal health. And he did no more pre-flight preparation than others. It’s just that Polyakov, being a professional doctor - Candidate of Medical Sciences, working at the Institute of Medical and Biological Problems of the Russian Academy of Sciences, knew like no one else in the cosmonaut corps the “human structure,” the body’s reactions to destabilizing factors and methods of compensating for them. What are they?

When a spacecraft is launched, the overloads range from 1g to 7g. This is extremely dangerous if the overload acts along the vertical axis, that is, from the head to the feet. In this position, a person, even with an overload of 3g lasting three seconds, experiences serious impairment of peripheral vision. If these values ​​are exceeded, the changes can become irreversible, and the person is guaranteed to lose consciousness.

Therefore, the seat in the ship is placed so that the acceleration acts in the horizontal plane. The astronaut also uses a special compensation suit. This makes it possible to maintain normal cerebral circulation with long-term overloads of 10g, and short-term overloads of up to 25g. The rate of increase in acceleration is also extremely important. If it exceeds a certain limit, then even minor overloads can be disastrous for the astronaut.

After a long stay in orbit, a detrained body endures the overloads that arise during landing, much more severely than during takeoff. Therefore, a few days before landing, the cosmonaut prepares using a special technique that involves physical exercise And medications. When landing, it is of great importance to orient the ship in dense layers of the atmosphere so that the overload axis is horizontal. During the first space flights, it was not possible to achieve proper stabilization of the ship, and therefore the astronauts sometimes lost consciousness during landing.

2. Zero gravity

Weightlessness is a much more difficult test for the body than overload. Because it acts for a long time and continuously, causing changes in a number of vital functions in the human body. Thus, weightlessness puts the central nervous system and receptors of many analyzer systems (vestibular apparatus, muscular-articular apparatus, blood vessels) under unusual operating conditions. As a result, blood flow slows down and blood accumulates in the upper torso.

The “meanness” of weightlessness is that the adaptive processes in physiological systems, the degree of their manifestation practically does not depend on the individual characteristics of the organism, but only on the duration of stay in weightlessness. That is, no matter how a person prepares for it on earth, no matter how powerful his body is, this has little effect on the adaptation process.

True, a person gets used to weightlessness quite quickly: dizziness and other negative phenomena stop. The astronaut “tastes” the fruits of weightlessness when he returns to earth.

If no methods of countering the destructive effects of weightlessness are used in orbit, then in the first few days the landing cosmonaut will experience the following changes:

1. Disturbance of metabolic processes, especially water-salt metabolism, which is accompanied by relative dehydration of tissues, a decrease in the volume of circulating blood, a decrease in the content of a number of elements in the tissues, in particular potassium and calcium;

2. Violation of the body’s oxygen regime during physical activity;

3. Impaired ability to maintain a vertical posture in static and dynamic conditions; a feeling of heaviness of parts of the body (surrounding objects are perceived as unusually heavy; there is a lack of training in dosing muscle efforts);

4. Hemodynamic disturbances during work of medium and high intensity; pre-fainting and fainting states are possible after moving from a horizontal to a vertical position;

5. Decreased immunity.

In orbit, a whole range of measures is used to combat the body-destroying effects of weightlessness. Increased intake of potassium and calcium. Negative pressure applied to the lower half of the body to drain blood. Barocompensation underwear. Electrical muscle stimulation. Dosed medication intake. Training on a treadmill and other exercise equipment.

3. Physical inactivity

A treadmill and various muscle trainers are also used to combat physical inactivity. In orbit, it is inevitable, since movements in zero gravity require significantly less effort than on earth. And upon returning to earth, even after daily grueling training, the astronauts experienced a decrease muscle mass. In addition, physical activity has a beneficial effect on the heart, which, as you know, is also a muscle.

4. Radiation

The effect of this factor on the human body has been well studied. World organization Healthcare has developed standards for radiation doses, the excess of which is harmful to health. These standards do not apply to astronauts.

It is believed that a person can undergo fluorography no more than once a year. At the same time, he receives a dose of 0.8 mSv (millisievert). An astronaut receives a daily dose of up to 3.5 mSv. However, by the standards of space medicine, such background radiation is considered acceptable. Because to a certain extent it is neutralized by medication. The daily radiation dose is not constant. Each astronaut has an individual dosimeter, which counts the millisieverts accumulated in the body. During a year in space you can get from 100 to 300 mSv.

“Of course, this is not a gift,” says Vyacheslav Shurshakov, head of the laboratory of methods and means of space dosimetry at the Institute of Medical and Biological Problems of the Russian Academy of Sciences, “but this is the specificity of the cosmonaut profession.”

In this case, the annual threshold dose is 500 mSv. Which is 25 times higher than the threshold for nuclear power plant employees, which is 20 mSv.

Well, the total dose after which an astronaut is not allowed to fly is 1000 mSv. At the same time when Gagarin flew, this figure was 4000 mSv. Sergei Avdeev came closest to the threshold, having flown a total of 747 days. The dose he received was 380 mSv.

Photo ITAR-TASS/Albert Pushkarev

Airplane. G-force is a dimensionless quantity, however, the unit of g-force is often denoted in the same way as gravitational acceleration. g. An overload of 1 unit (or 1g) means straight flight, 0 means free fall or weightlessness. If an airplane turns at a constant altitude with a bank of 60 degrees, its structure experiences an overload of 2 units.

The permissible overload value for civil aircraft is 2.5. An ordinary person can withstand any overload up to 15G for about 3-5 seconds without shutting down, but a person can withstand large overloads of 20-30G or more without shutting down for no more than 1-2 seconds depending on the size of the overload, for example 50G = 0.2 sec. Trained pilots in anti-g suits can tolerate g-forces from −3…−2 to +12. Resistance to negative, upward overloads is much lower. Usually, at 7-8 G, the eyes “turn red” and the person loses consciousness due to a rush of blood to the head.

Overload is a vector quantity directed in the direction of the speed change. This is fundamental for a living organism. When overloaded, human organs tend to remain in the same state (uniform rectilinear motion or rest). With a positive overload (head-legs), blood flows from the head to the legs. The stomach goes down. If negative, blood comes to the head. The stomach may rupture along with its contents. When another car crashes into a stationary car, the person sitting will experience back-chest overload. Such an overload can be tolerated without much difficulty. During takeoff, astronauts endure overload while lying down. In this position, the vector is directed chest-back, which allows you to withstand several minutes. Cosmonauts do not use anti-g load devices. They are a corset with inflatable hoses that inflate from air system and hold the outer surface of the human body, slightly preventing the outflow of blood.

Notes

Wikimedia Foundation. 2010.

See what “Overload (aviation)” is in other dictionaries:

Overload: Overload (aviation) the ratio of lift to weight Overload (engineering) in accelerating objects Overload (chess) a chess situation where the pieces (piece) are unable to cope with the assigned tasks. Overload... ... Wikipedia

1) P. at the center of mass, the ratio n of the resulting force R (the sum of thrust and aerodynamic force, see Aerodynamic forces and moments) to the product of the mass of the aircraft m and the acceleration of free fall g: n = R/mg (when determining P. for ... ... Encyclopedia of technology

The largest neymax and the smallest neymin permissible values ​​of normal overload ny in terms of structural strength. The value of e.p. is determined on the basis of strength standards for various design cases, for example, for maneuver, flight in bumpy conditions. By… … Encyclopedia of technology

The astronaut, dressed in a heavy and uncomfortable spacesuit, stopped for a moment at the hatch leading inside the spacecraft, looked back at the crowd of mourners standing below, raised his hand in farewell greeting and disappeared into the dark opening of his compartment. He sat comfortably in a chair made of a porous, soft, plastic material, secured the straps, connected the contacts of the suit to the general signal wiring network of the ship and pressed one of the buttons on the control panel, giving a signal of readiness for radio reception. A minute later he heard the voice of the flight commander:

It's okay, just a few more minutes left! - The astronaut turned on the general radio broadcasting network and heard the voice of a radio commentator, who reported details of preparations for the launch and colorfully described pre-launch emotions and moods. The cosmonaut once again recalled the scenes of farewell to his family and friends, and to the scientists leading space research.

I declare readiness number one! - the commander’s voice suddenly rang out through the helmet-mounted helmet. After this, the exciting countdown so familiar to all astronauts began, each number of which carried with it an ever-increasing tension of anticipation.

Attention, attention, attention! Ten... nine... eight... seven... six... five... four... three... two... one... Start!

The astronaut's cabin was first pierced by a vibration coming in waves from somewhere below; Then there was a muffled thunder, which quickly turned into a long continuous roar. A long stream of fiery lightning appeared from under the bottom of the rocket, and its huge body, amid smoke and roar, slowly separated from the ground, gradually increasing its speed.

While all the mourners at the cosmodrome, trying to follow the flight of the spacecraft, raised their heads higher and higher, crucial minutes for the astronaut began in the cockpit.

Overload is growing! - he reported on the radio. - Everything is in order, the devices are working properly! - These were last words, which the astronaut managed to pronounce without much difficulty, because suddenly some powerful force pressed his body to the chair. A huge weight fell on his chest so that the astronaut could not take a single breath of air. It seemed that a little more and he would be crushed. The legs and arms became heavy, as if they were made of lead, the muscles of the face twisted and pulled back, the eyes, like two balls, were squeezed deep into the skull.

The astronaut also tried to say something into the microphone, but to no avail. Only incomprehensible muttering came out of his lips. Abandoning attempts at conversation, the cosmonaut focused on his experiences, tried to resist the powerful force, and take a breath of air through his lips.

Suddenly he felt a sharp sense of relief.

The end of the first stage engine of the rocket, flashed through his head.

But this was only a momentary break in the operation of the engines. As soon as the first stage of the rocket separated, the second stage engines turned on.

The speed began to increase again, and with it the load increased, the astronaut’s body was again pressed into the chair cushions. A few minutes later, the fuel in the engines of the second stage of the rocket ran out of fuel, there was a short break, after which the engines of the third stage started working. And although the body still had great difficulty overcoming the load, the astronaut thought about the imminent end of the test. He knew that the third stage engines had to work for a very short time, and in a few minutes - the end of the overloads!

And so it happened. Ninety seconds later the engines stopped firing and there was a sudden silence.

The transition was so sharp and fast that neither the body nor the mind of the astronaut had time to prepare for it. His heart was pounding in his chest, his chest was rapidly rising and falling, the astronaut was gasping for air with his open mouth and breathing frequently, shallowly. But suddenly everything went away.

* * *

Oof! - the astronaut sighed deeply and with a feeling of relief. The first part of the flight is over. He turned on the microphone and, clearly highlighting the syllables, said:

Entered orbit. All equipment and devices operate smoothly. I feel good.

We tried to describe an ordinary, ordinary launch of an astronaut into space, when the task is limited only to an orbital flight around the Earth. Such a start still represents a difficult test for the human body due to the action of the acceleration force.

What kind of power is this?

How to measure it?

Let's imagine for a moment that we went up in a hot air balloon, and, choosing a convenient moment, threw out the weight. At the moment of release, the speed of the weight will be zero, but already at the end of the first second of flight it will be 9.8 meters per second, at the end of the second second - twice as much, that is, 19.6 m/sec, at the end of the third second - at three times more, that is, 29.4 m/sec and so on. The weight's flight speed increases by 9.8 m/sec every second.

It is this value that is the unit of acceleration. In science, it is usually denoted by the Latin letter “g”. If any physical body rises or falls vertically, the force of acceleration depends on gravity or, what is the same, on the force of gravity. However, there are other types of acceleration, for example during rotation, when centrifugal force appears, or in an airplane, when the pilot, emerging from a dive, goes to the so-called “slide”.

All these types of acceleration are considered positive.

During sharp braking of a fast-moving train or car, an acceleration force with the opposite sign arises - negative acceleration. In this case, the force of inertia caused by braking, that is, loss of speed, or, if you like, negative acceleration, throws the passenger forward. During car accidents, people most often die from negative acceleration.

There was a time when acceleration issues were considered only theoretically. After the advent of high-speed aircraft, acceleration issues began to be studied practically. About thirty years ago, a lot of noise was made in aviator circles when a pilot, while exiting a dive flight, lost control and crashed. It turned out that under the influence of the acceleration force that arose during a sharp change in direction during high flight speed, the pilot lost consciousness and lost control of the controls.

What is the cause of loss of consciousness? After all, he was an experienced, strong pilot with excellent health!

At the moment of exit from the diving flight, a centrifugal force appeared, which caused a negative acceleration of the order of two to three. As the centrifugal force increased, the weight of the pilot's body and his blood increased. When the acceleration reached 4 g, a significant part of the blood, under the influence of this force, drained from the brain and moved to the lower parts of the body, as a result of which the pilot began to lose his vision. A few moments later, when the acceleration had decreased, the pilot could see nothing, as if wearing a black blindfold.

However, the acceleration continued to increase because the pilot was steering the plane through a curve at the end of which the plane would be in a vertical upward flight position. More and more blood flowed from the brain to the pilot’s heart. Formidable symptoms appeared. It seemed to the pilot that his heart was falling sharply downwards, that it had moved to the lower abdomen, and the liver was even lower, somewhere near the knees. The pilot could no longer see anything at all, and he had to strain all his strength not to lose consciousness. Until now, he had never experienced such a state, but the pilot did not want to give up the fight, did not want to submit to the weakness of his own body. He believed that all unpleasant sensations would pass as soon as the centrifugal force ceased.

But this time he miscalculated. He did not take into account the high initial speed at the moment of exit from the dive flight and, thus, the significant amount of centrifugal force that appeared at this time.

The unsuccessful flight continued. The pilot's brain, deprived of blood, stopped working. When the acceleration force reached 10 g, the pilot’s body no longer weighed 85 kg, as usual, but 850 kg. Each cubic centimeter of blood weighed not 1 gram, but 10, so blood became heavier than iron and weighed almost the same as mercury.

Making a final effort, the pilot decided to hold out for one more second before pulling the control lever away from himself to relieve the monstrous pressure of the centrifugal force. However, at the same moment he lost consciousness. I pulled the string, couldn’t stand it and... lost.

The plane lost control, the strong and heavy machine began to fall randomly and eventually crashed into the ground. Such was the tragic end of this flight.

This case was discussed for a long time in aviator circles, especially among physiologists involved in the problems of aviation medicine. Comprehensive Scientific research.

It has been established that with an acceleration of about 5 g, even well-trained and persistent pilots lose their vision, the ability to breathe, and they develop severe pain in their ears. If this condition lasts no more than 30–40 seconds, the body quickly overcomes it, but if it continues longer, serious disorders and even injuries can occur.

After the era of jet flight began in aviation, and aircraft speeds began to exceed 1000 km/h, scientists began to obtain a lot of information about the body's resistance to overload by observing the behavior of pilots while performing aerobatic maneuvers at high speeds. Catapults were also built on the ground, with the help of which dummies equipped with numerous research instruments were thrown into the air with a high initial speed. Phenomena occurring in the parachutist’s body during the transition from free fall to flight with an open parachute were also noted.

But such studies have been incomplete. It was necessary to create more versatile, convenient and accurate instruments and installations for studying the phenomena occurring in the human body under the influence of overloads.

"CAROUSEL"

Soon such an installation was built. This is a centrifuge, which pilots and cosmonauts in some countries have dubbed the “carousel”. It has become the main installation for studying the body's resistance to overload. What does this “carousel” look like?

In the vast round hall, about a meter above the floor, one can see a lattice console made of steel pipes, somewhat reminiscent of a construction crane. At one end, the console is mounted on a vertical axis with an electric drive with a power of 6000 hp. With. The length of the carousel console is 17 meters; at the other end of the grille there is a cabin with a place for a person to sit; The cabin houses a variety of complex research equipment.

The cabin is hermetically sealed, which makes it possible to set the temperature and pressure inside it within very wide limits, that is, it is possible to create conditions in it that are very close to those that can prevail in the astronaut’s cabin during a flight in space.

Special mechanism The cabin suspension automatically sets it during testing in such a position that the centrifugal force acts on a person inside the cabin in a straight line, similar to how this force acts during space flight. This makes calculations easier for the doctors observing the experiment.

Of all the numerous devices located in the cabin, it is worth paying attention to the television camera lens located directly above the head of the cabin passenger. Once the pilot takes his place in the cockpit, scientists attach a variety of sensors to his body, connected to electronic control equipment. Thanks to this, all phenomena occurring in the pilot’s body during centrifugation are accurately recorded on recording tapes.

As soon as the “carousel” console begins to rotate, a centrifugal force arises in the cabin, which acts on the pilot’s body like the acceleration force in the cabin of a spaceship or airplane. As the number of revolutions increases, this force also increases and can reach a value of 40 g, at which the pilot’s body weight increases to 3200 kg. Such an overload for a person can result in death, so it is created only in exceptional cases during experiments with animals.

It should be noted, however, that at the American air base in Jonesville (the centrifuge installed there is what we are describing), a record set by one of the pilots became famous at one time. Despite the fact that the acceleration exceeded the dangerous limit of 5 g, the pilot did not give a signal to stop the experiment, and he refused the proposal sent by telephone to stop the centrifuge. Moreover, he demanded an increase in speed. The pilot withstood acceleration of 8 g, then 10 and 12 g. And only when the acceleration force reached 14 g and remained at this level for two minutes, the pilot finally made it clear that he could no longer stand it.

The ability of the human body to withstand overload is not the same different persons and largely depends on individual qualities, degree of training, state of health, age of the person, etc. Basically, a normal person feels bad at 5 g, but trained pilots in exceptional health can withstand about 10 g for 3-5 minutes.

What kind of overloads have cosmonauts had to endure so far?

According to Soviet data, the world's first man to fly into outer space, Yuri Gagarin, withstood an overload of about 4 g during the launch. American researchers report that astronaut Glenn withstood an increasing overload of up to 6.7 g from the moment of launch until the moment of separation of the first stage of the rocket, that is, for 2 minutes and 10 seconds. After separation of the first stage, the acceleration increased from 1.4 to 7.7 g over 2 minutes and 52 seconds.

Since under these conditions the acceleration, and with it the overloads, increase gradually and do not last long, the strong, trained body of the astronauts endures them without any harm.

JET SLED

There is another type of installation for studying the reaction of the human body to overload. This is a jet sled, which is a cabin moving along a rail track of considerable length (up to 30 kilometers). The speed of the cabin on the skid reaches 3500 km/h. At this stand it is more convenient to study the body’s reactions to overloads, since they can create not only positive, but also negative accelerations. After a powerful jet engine gives the sled a speed of about 900 m/sec (that is, the speed of a rifle bullet) a few seconds after launch, the acceleration can reach 100 g. During sharp braking, also with the help of jet engines, negative acceleration can even reach 150 g.

Tests on jet sleds are suitable mainly for aviation, not astronautics, and, in addition, this installation is much more expensive than a centrifuge.

CATAPULTS

Catapults operate on the same principle as jet sleds, which have inclined guides along which the seat with the pilot moves. Catapults are particularly useful in aviation. They test the body's reactions of pilots, who may in the future have to eject in an airplane crash to save their lives. In this case, the cockpit and the pilot are shot from the crashed jet plane and using a parachute we descend to the ground. Catapults are capable of accelerating no more than 15 g.

"IRON SIREN"

In search of a way to prevent the harmful effects of overload on the human body, scientists have found that immersion of a person in a liquid medium, the density of which approximately corresponds to the average density of the human body, is of great benefit.

Pools were built filled with a liquid suspension of appropriate density, with a breathing device; Experimental animals (mice and rats) were placed in the pools, after which centrifugation was carried out. It turned out that the resistance of mice and rats to overload increased tenfold.

In one of the American scientific institutes, swimming pools were built that made it possible to place a person in them; (the pilots subsequently nicknamed these pools “iron sirens”). The pilot was placed in a bath filled with a liquid of appropriate density and centrifuged. The results exceeded all expectations - in one case the overloads were increased to 32 g. The person withstood this overload for five seconds.

True, the “iron siren” is imperfect from a technical point of view and, in particular, there are objections from the point of view of convenience for the astronaut. However, one should not judge too hastily. Perhaps in the near future, scientists will find a way to improve testing conditions at such a facility.

It should be added that resistance to overloads largely depends on the position of the astronaut’s body during the flight. Based on many tests, scientists have found that a person can more easily endure overloads in a semi-lying position, since this position is more convenient for blood circulation.

HOW TO INCREASE STABILITY

We have already mentioned that in the conducted space flights the overloads were relatively small and lasted only a few minutes. But this is only the beginning of the space age, when human flights into space take place in orbits relatively close to Earth.

Now we stand on the threshold of flights to the Moon, and within the lifetime of the next generation - to Mars and Venus. It may then be necessary to experience significantly greater accelerations, and the astronauts will be subjected to significantly greater overloads.

There is also the problem of astronauts’ resistance to small, but long-term, constant overloads that last throughout the entire interplanetary journey. Preliminary data suggest that constant acceleration on the order of fractions, “g,” is tolerated by a person without any difficulty. Projects for such rockets have already been developed, the engines of which will operate with constant acceleration. Despite the fact that during the experiment itself people had to endure various unpleasant phenomena, the experiments did not bring them any harm.

It is possible that in the future it will be possible to increase the human body’s resistance to overload in another way. Interesting experiments were carried out by scientists at the University of Cambridge in the USA. They subjected pregnant mice to constant acceleration of about 2 g until they produced pups, which were kept in a centrifuge for the rest of their lives until death. Mice born in such conditions felt great under the influence of a constant overload of 2 g, and their behavior was no different from the behavior of their counterparts living in normal conditions.

We are far from the idea of ​​​​conducting similar experiments with people, but we still believe that the phenomenon of such adaptability of the body to overloads can solve a number of problems facing biologists.

It is also possible that scientists will find a way to neutralize acceleration forces, and a person equipped with appropriate equipment will easily endure all the phenomena associated with overloads. Even greater hopes are associated with the freezing method, when a person’s sensitivity drops sharply (we write about this below).

Progress in the field of increasing the resistance of the human body to overload is very great and continues to develop. Already managed to achieve great success in increasing durability by giving the human body the correct position during flight, using a soft chair covered with spongy plastic and specially designed spacesuits. Perhaps the near future will bring even greater success in this area.

WHEN EVERYTHING AROUND VIBRATES

Of the many dangers that await an astronaut during a flight, one more should be mentioned, related to the aerodynamic features of the flight and the operation of jet engines. This danger, although fortunately not very great, comes from vibration.

During launch, powerful engines operate, and the entire rocket structure is subject to strong vibration. The vibration is transmitted to the astronaut’s body and can lead to very unpleasant consequences for him.

The harmful effects of vibration on the human body have been known for a long time. Indeed, workers who use a pneumatic hammer or drill for a more or less long time become ill with the so-called vibration disease, which is manifested not only by severe pain in the muscles and joints of the upper extremities, but also by pain in the abdomen, heart, and head. Shortness of breath appears and breathing becomes difficult. The sensitivity of the body largely depends on which of the internal organs is most susceptible to vibration. React differently to vibration internal organs digestion, lungs, upper and lower limbs, eyes, brain, throat, bronchi, etc.

It has been established that the vibration of a spacecraft has a harmful effect on all tissues and organs of the human body - and vibration of high frequency is the worst tolerated, that is, one that is difficult to notice without precise instruments. During experiments with animals and people, it was found that under the influence of vibration, their heartbeat first increases, blood pressure increases, then changes appear in the composition of the blood: the number of red blood cells decreases, the number of white blood cells increases. The general metabolism is disrupted, the level of vitamins in tissues decreases, and changes appear in the bones. Interestingly, body temperature largely depends on the frequency of vibration. When the oscillation frequency increases, the body temperature increases, and when the frequency decreases, the temperature decreases.

Therefore, it is not surprising that the vibration of a spacecraft can cause significant disruptions in the vital functions of the body and can negatively affect the mental work of an astronaut.

Of course, the consequences of vibration can become dangerous if it is exposed to the human body for a long time. If the astronauts had to endure vibration for several days, it would lead to complete and irreversible disruption of life, with all the ensuing consequences.

Fortunately, this problem is not as big as it seems at first glance. The fact is that the duration of vibration during a rocket launch is only a few minutes, and although the crew of the spacecraft experiences some inconvenience, they last for such a short time that they do not cause any harm. The vibration lasts somewhat longer as the ship passes through the atmosphere during landing. But this is not that dangerous either. In addition, the special design of the flexible and elastic seat suspension, which isolates the astronauts from the rocket body, as well as the soft plastic upholstery of the seats and backs of the seats, significantly reduce the vibration transmitted from the rocket body to the astronaut’s body.