You may not be interested in space, but you've probably read about it in books, seen in films and games. In most works, as a rule, gravity is present - we do not pay attention to it and take it for granted. Except that's not true.

Massive ones attract stronger, smaller ones weaker.

Materiel

The Earth is just such a massive object. Therefore, people, animals, buildings, trees, blades of grass, a smartphone or a computer - everything is attracted to the Earth. We are used to this and never think about such a small thing.

The main consequence of the Earth's gravity for us is acceleration free fall, also known as g. It is equal to 9.8 m/s². Any body in the absence of support will equally accelerate towards the center of the Earth, gaining 9.8 meters of speed every second.

Thanks to this effect, we stand straight on our feet, distinguish between “up” and “down,” drop things, and so on. Take away the Earth's gravity, and all usual actions will be turned upside down.

This is best known to astronauts who spend a significant part of their lives on the ISS. They relearn how to drink, walk, and cope with basic needs.

Here are some examples.

At the same time, in the mentioned films, TV series, games and other science fiction, gravity on spaceships “simply exists.” The creators don’t even explain where it came from - and if they do, it’s unconvincing. Some kind of “gravity generators”, the operating principle of which is unknown. This is no different from “it just is” - it’s better not to explain at all in this case. It's more honest.

Theoretical models of artificial gravity

There are several ways to create artificial gravity.

Lots of mass

The first (and most “correct”) option is to enlarge the ship, make it very massive. Then gravitational interaction will provide the required effect.

But unreality this method It’s obvious: such a ship requires a lot of material. And something needs to be done about the uniform distribution of the gravitational field.

Constant acceleration

Since we need to achieve a constant gravitational acceleration of 9.8 m/s², why not do spacecraft in the form of a platform that will accelerate perpendicular to its plane with this same g?

Thus desired effect will be achieved - but there are several problems.

First, you need to get fuel from somewhere to ensure constant acceleration. And even if someone suddenly comes up with an engine that does not require the emission of matter, the law of conservation of energy will not disappear anywhere.

Secondly, the problem lies in the very nature of constant acceleration. Our physical laws say: you cannot accelerate forever. The theory of relativity says the opposite.

Even if the ship periodically changes direction, to ensure artificial gravity he must constantly fly somewhere. No hanging near planets. If the ship stops, gravity will disappear.

So this option does not suit us either.

Carousel carousel

And here is where the fun begins. Everyone knows how the carousel works - and what effects a person experiences in it.

Everything that is on it tends to jump out in proportion to the speed of rotation. From the side of the carousel, it turns out that everything is affected by a force directed along the radius. Quite a “gravity” thing.

So we need a barrel-shaped ship that will rotate around its longitudinal axis. Such options are quite common in science fiction.

When rotating around an axis, a centrifugal force is generated directed along the radius. Dividing the force by the mass, we get the desired acceleration.

All this is calculated using a simple formula:

A=ω²R,

where a is the acceleration, R is the radius of rotation, and ω is the angular velocity measured in radians per second (a radian is approximately 57.3 degrees).

What do we need for normal life on an imaginary space cruiser? A combination of the ship's radius and angular velocity, whose derivative will ultimately give 9.8 m/s².

We have seen something similar in a number of works: “2001: A Space Odyssey” by Stanley Kubrick, the series “Babylon 5”, “Interstellar” by Nolan, the novel “Ringworld” by Larry Niven, the universe of the Halo games.

In all of them, the acceleration of gravity is approximately equal to g - everything is logical. However, these models also have problems.

Carousel problems

The most obvious problem is perhaps easiest to explain using the example of A Space Odyssey. The radius of the ship is approximately 8 meters - to achieve an acceleration equal to g, an angular velocity of approximately 1.1 rad/s is required. This is approximately 10.5 revolutions per minute.

With such parameters, the “Coriolis effect” comes into force - at different “heights” from the floor, different forces act on moving bodies. And it depends on the angular velocity.

So in our virtual design we can't rotate the ship too fast as this will cause sudden drops and problems with vestibular apparatus. And taking into account the acceleration formula, we cannot afford a small radius of the ship.

Therefore, the “Space Odyssey” model is no longer necessary. The problem is roughly the same with the ships in Interstellar, although there everything is not so obvious with the numbers.

The second problem is on the other side of the spectrum. In Larry Niven's novel Ringworld, the ship is a giant ring with a radius approximately equal to the radius of the Earth's orbit (1 AU ≈ 149 million km). Thus, it rotates at a quite satisfactory speed so that a person does not notice the Coriolis effect.

It would seem that everything fits together, but there is a problem here too. One revolution will take 9 days, which will create huge overloads with such a ring diameter. This requires very strong material. On at the moment humanity cannot produce such a strong structure - not to mention the fact that somewhere you need to take so much matter and still build everything.

In the case of Halo or Babylon 5, all the previous problems seem to be absent: and the rotation speed is sufficient so that the Coriolis effect does not occur negative impact, and building such a ship is realistic (hypothetically).

But these worlds also have their drawbacks. Its name is angular momentum.

By spinning the ship around its axis, we turn it into a giant gyroscope. And it is difficult to deflect the gyroscope from its axis due to the angular momentum, the amount of which must be conserved in the system. This means that it will be difficult to fly somewhere in a certain direction. But this problem can be solved.

How it should be

This solution is called the “O’Neill cylinder”: we take two identical cylinder ships, connected along an axis and each rotating in its own direction. As a result, we have zero total angular momentum, and there should be no problems with directing the ship in the right direction.

With a ship radius of 500 meters or more (as in Babylon 5), everything should work as it should.

Bottom line

What conclusions can we draw about the implementation of artificial gravity in spacecraft?

Of all the options, the most realistic one is the rotating structure, in which the force directed “downwards” is provided centripetal acceleration. It is impossible to create artificial gravity on a ship with flat parallel structures like decks, given our modern understanding of the laws of physics.

The radius of the rotating ship must be sufficient so that the Coriolis effect is negligible for humans. Good examples Among the invented worlds, the already mentioned Halo and Babylon 5 can serve.

To control such ships, you need to build an O’Neill cylinder - two “barrels” rotating in different directions to ensure zero total angular momentum for the system. This will allow adequate control of the spacecraft - a very realistic recipe for providing astronauts with comfortable gravitational conditions.

And until we can build something like this, I would like science fiction writers to pay more attention to physical realism in their works.

For objects in space, rotation is a common thing. When two masses move relative to each other, but not towards or away from each other, their gravitational force creates a torque. As a result, in solar system all planets revolve around the sun.

But this is something that man did not influence. Why do spacecraft rotate? To stabilize the position, constantly direct the instruments in the right direction and in the future - to create artificial gravity. Let's look at these questions in more detail.

Rotation stabilization

When we look at a car, we know which way it is going. It is controlled through interaction with external environment- wheel traction with the road. Where the wheels turn, the whole car goes there. But if we deprive him of this grip, if we send the car on bald tires to roll on ice, then it will spin in a waltz, which will be extremely dangerous for the driver. This type of motion rarely occurs on Earth, but is the norm in space.

B.V. Rauschenbach, academician and Lenin Prize laureate, wrote in “Spacecraft Motion Control” about three main types of motion control problems spacecraft:

1. Obtaining the desired trajectory (controlling the movement of the center of mass),
2. Orientation control, that is, obtaining the desired position of the spacecraft body relative to external landmarks (control rotational movement around the center of mass);
3. The case when these two types of control are implemented simultaneously (for example, when spacecraft approach each other).

The rotation of the device is carried out in order to ensure a stable position of the spacecraft. This is clearly demonstrated by the experiment in the video below. The wheel attached to the cable will take a position parallel to the floor. But if this wheel is first spun, it will retain its vertical position. And gravity will not interfere with this. And even a two-kilogram load attached to the second end of the axle will not change the picture very much.

An organism adapted to life in conditions of gravity manages to survive without it. And not only to survive, but also to work actively. But this small miracle not without consequences. The experience accumulated over decades of human space flights has shown that a person experiences a lot of stress in space, which leaves a mark on the body and psyche.

On Earth, our body fights gravity, which pulls blood down. In space, this struggle continues, but there is no gravitational force. That's why astronauts are puffy. Intracranial pressure increases, the pressure on the eyes increases. It's deforming optic nerve and affects the shape eyeballs. The plasma content in the blood decreases, and due to the decrease in the amount of blood that needs to be pumped, the heart muscles atrophy. The bone mass defect is significant and the bones become fragile.

To combat these effects, people in orbit are forced to exercise daily physical training. Therefore, the creation of artificial gravity is considered desirable for long-term space travel. Such technology should create physiologically natural conditions for human habitation on board the vehicle. Konstantin Tsiolkovsky also believed that artificial gravity would help solve many medical problems human flight into space.

The idea itself is based on the principle of equivalence between the gravitational force and the force of inertia, which states: “The forces of gravitational interaction are proportional to the gravitational mass of the body, while the forces of inertia are proportional to the inertial mass of the body. If the inertial and gravitational masses are equal, then it is impossible to distinguish which force acts on a given rather small body - gravitational or inertial force.”

This technology has disadvantages. In the case of a device with a small radius, different forces will affect the legs and head - the further away from the center of rotation, the stronger the artificial gravity. The second problem is the Coriolis force, due to the influence of which a person will be rocked when moving relative to the direction of rotation. To avoid this, the device must be huge. And the third important question associated with the complexity of developing and assembling such a device. When creating such a mechanism, it is important to consider how to make it possible for the crew to have constant access to the compartments with artificial gravity and how to make this torus move smoothly.

IN real life This technology has not yet been used for the construction of spaceships. An inflatable module with artificial gravity was proposed for the ISS to demonstrate the prototype Nautilus-X spacecraft. But the module is expensive and would create significant vibrations. Making the entire ISS with artificial gravity with current rockets is difficult to implement - everything would have to be assembled in orbit in parts, which would greatly complicate the scope of operations. And this artificial gravity would negate the very essence of the ISS as a flying microgravity laboratory.

Concept of an inflatable microgravity module for the ISS.

But artificial gravity lives in the imagination of science fiction writers. The Hermes ship from the movie The Martian has a rotating torus in the center, which creates artificial gravity to improve the condition of the crew and reduce the effects of weightlessness on the body.

The US National Aerospace Agency has developed a scale of TRL technology readiness levels of nine levels: from the first to the sixth - development within the framework of research and development work, from the seventh and above - development work and demonstration of technology performance. The technology from the movie “The Martian” so far corresponds only to the third or fourth level.

There are many uses of this idea in science fiction literature and films. In Arthur C. Clarke's A Space Odyssey series of novels, Discovery One was described as being shaped like a dumbbell, the purpose of which was to separate nuclear reactor with engine from residential area. The equator of the sphere contains a “carousel” with a diameter of 11 meters, rotating at a speed of about five revolutions per minute. This centrifuge creates a level of gravity equal to that of the Moon, which should prevent physical atrophy in microgravity conditions.

"Discovery One" from "A Space Odyssey"

In the anime series Planetes, the ISPV-7 space station has huge rooms with the usual Earth gravity. The living area and the growing area are located in two tori rotating in different directions.

Even hard science fiction ignores the enormous cost of such a solution. Enthusiasts took as an example the ship “Elysium” from the film of the same name. Wheel diameter is 16 kilometers. Weight - about a million tons. Sending cargo into orbit costs $2,700 per kilogram; SpaceX Falcon will reduce this figure to $1,650 per kilogram. But 18,382 launches will have to be carried out to deliver this amount of materials. This is 1 trillion 650 billion US dollars - almost one hundred annual budgets of NASA.

Real settlements in space, where people can enjoy the usual 9.8 m/s² acceleration due to gravity, are still a long way off. Perhaps the reuse of rocket parts and space elevators will bring such an era closer.

Gennady Brazhnik, April 23, 2011
Looking at the World, open your eyes... (ancient Greek epic)
How to create artificial gravity?
The fiftieth anniversary of space exploration, celebrated this year, showed enormous potential human intelligence in the matter of knowledge of the surrounding Universe. International Space Station (ISS) - manned orbital station- joint international project, in which 23 countries participate,
convincingly proves the interest of national programs in the development of both near and far outer space. This applies to both the scientific, technical and commercial side of the issue under consideration. At the same time, the main issue standing in the way of mass space exploration is the problem of weightlessness or the absence of gravity on existing space objects. "Gravity ( universal gravity, gravity) - universal fundamental interaction between all material bodies. In the approximation of low speeds and weak gravitational interaction, it is described by Newton’s theory of gravity, in the general case it is described by Einstein’s general theory of relativity” - this is the definition given by modern science this phenomenon. The nature of gravity is currently unclear. Theoretical developments within the framework of various gravitational theories do not find their experimental confirmation, which suggests a premature approval scientific paradigm by the nature of gravitational interaction, as one of the four fundamental interactions. In accordance with Newton's theory of gravity, the gravitational force of Earth's attraction is determined by the expression F=m x g, where m is the mass of the body, and g is the acceleration of gravity. "The acceleration of gravity g is the acceleration imparted to a body in a vacuum by the force of gravity, that is, the geometric sum of the gravitational attraction of a planet (or other astronomical body) and the inertial forces caused by its rotation. In accordance with Newton's second law, the acceleration of gravity is equal to the force of gravity, unit mass acting on an object. The value of the acceleration of gravity for the Earth is usually taken equal to 9.8 or 10 m/s╡. The standard (“normal”) value adopted when constructing systems of units is g = 9.80665 m/s╡, and in technical calculations g = 9.81 m/s╡ is usually taken. The value of g has been defined as the "average" in some sense acceleration due to gravity on Earth, approximately equal to the acceleration due to gravity at latitude 45.5° at sea level. The actual acceleration due to gravity at the surface of the Earth depends on latitude, time of day, and other factors It varies from 9.780 m/s╡ at the equator to 9.832 m/s╡ at the poles." This scientific uncertainty also raises a number of questions related to the gravitational constant in General theory relativity. Is it so constant if under the conditions of gravity we have such a scatter of parameters. The main arguments of almost all gravitational theories are the following: “The acceleration of gravity consists of two components: gravitational acceleration and centripetal acceleration. The differences are due to: centripetal acceleration in the reference frame associated with the rotating Earth; inaccuracy of the formula due to the fact that the mass of the planet is distributed over a volume that has a geometric shape different from an ideal sphere (geoid); the heterogeneity of the Earth, which is used to search for minerals by gravitational anomalies." At first glance, these are quite convincing arguments. Upon closer examination, it becomes obvious that these arguments do not explain physical nature phenomena. In the Earth's reference frame associated with the centripetal acceleration at each geographic point, all components of the measurement of the acceleration of gravity are located. Therefore, both the object of measurement and the equipment being measured are subject to the same influence, including the distributed mass of the Earth and gravitational anomalies. Therefore, the measurement result should be constant, but this is not the case. In addition, the uncertainty of the situation is caused by the theoretical calculated values ​​of the acceleration of free fall at the flight altitude of the ISS - g=8.8 m/s(2). The actual value of local gravity on the ISS is determined within the range of 10(−3)...10(−1) g, which determines weightlessness. Statements that the ISS is moving from the first escape velocity and is in a state of free fall. What then about geostationary satellites? At this calculated value of g, they would have fallen to Earth long ago. In addition, the mass of any body can be defined as quantitative and qualitative characteristics own electric charge. All these considerations lead to the conclusion that the nature of the Earth's gravity does not depend on the ratio of the masses of interacting objects, but is determined by the Coulomb forces of the electrical interaction of the Earth's gravitational field. If we fly in a horizontal flight on an airplane, at an altitude of ten km, then the laws of gravity are fully satisfied, but during the same flight on the ISS at an altitude of 350 km, there is practically no gravity. This means that within these heights there is a mechanism that allows gravity to be determined as the force of interaction of material bodies. And the value of this force is determined by Newton's law. For a person weighing 100 kg, the force of gravitational attraction at ground level, excluding atmospheric pressure, should be F = 100 x 9.8 = 980 n. According to existing data, the Earth's atmosphere is electrically heterogeneous structure, the layering of which is determined by the ionosphere. “The ionosphere (or thermosphere) is a part of the Earth’s upper atmosphere that is highly ionized due to irradiation by cosmic rays coming primarily from the Sun. The ionosphere consists of a mixture of a gas of neutral atoms and molecules (mainly nitrogen N2 and oxygen O2) and quasineutral plasma ( the number of negatively charged particles is only approximately equal to the number of positively charged ones). The degree of ionization becomes significant already at an altitude of 60 kilometers and steadily increases with distance from the Earth. Depending on the density of charged particles N, layers D, E and F are distinguished in the ionosphere. Layer D In the region. D (60-90 km) the concentration of charged particles is Nmax~ 10(2)-10(3) cm−3 - this is the region of weak ionization. The main contribution to the ionization of this region is made. x-ray radiation Sun. Also, a small role is played by additional weak sources of ionization: meteorites burning at altitudes of 60-100 km, cosmic rays, as well as energetic particles of the magnetosphere (brought into this layer during magnetic storms). Layer D is also characterized sharp decline degree of ionization at night. Layer E Region E (90-120 km) is characterized by plasma densities up to Nmax~ 10(5) cm−3. In this layer, an increase in the electron concentration is observed in daytime, since the main source of ionization is solar short-wave radiation, moreover, the recombination of ions in this layer occurs very quickly and at night the ion density can drop to 10(3) cm−3. This process is counteracted by the diffusion of charges from the region F, located above, where the concentration of ions is relatively high, and by night sources of ionization (geocorona radiation of the Sun, meteors, cosmic rays, etc.). Sporadically, at altitudes of 100-110 km, an ES layer appears, very thin (0.5-1 km), but dense. A feature of this sublayer is the high concentration of electrons (ne~10(5) cm−3), which have a significant influence on the propagation of medium and even short radio waves reflected from this region of the ionosphere. Layer E in effect relatively high concentration free current carriers plays important role in the propagation of medium and short waves. Layer F Region F is now called the entire ionosphere above 130-140 km. Maximum ion formation is achieved at altitudes of 150-200 km. During the daytime, the formation of a “step” in the distribution of electron concentration caused by powerful solar radiation is also observed. ultraviolet radiation. The region of this step is called region F1 (150-200 km). It significantly affects the propagation of short radio waves. The upper part of the F layer up to 400 km is called the F2 layer. Here the density of charged particles reaches its maximum - N ~ 10(5)-10(6) cm−3. At high altitudes, lighter oxygen ions predominate (at an altitude of 400-1000 km), and even higher - hydrogen ions (protons) and small quantities- helium ions." Two main modern theories atmospheric electricity were created in the mid-twentieth century by the English scientist Charles Wilson and the Soviet scientist Ya. I. Frenkel. According to Wilson's theory, the Earth and the ionosphere play the role of plates of a capacitor charged by thunderclouds. The potential difference arising between the plates leads to the appearance electric field atmosphere. According to Frenkel's theory, the electric field of the atmosphere is explained entirely by electrical phenomena occurring in the troposphere - the polarization of clouds and their interaction with the Earth, and the ionosphere does not play a significant role in the course of atmospheric electrical processes. Generalizing these theoretical concepts of electrical interaction in the atmosphere implies considering the issue of Earth's gravity from the point of view of electrostatics. Based on the above generally known facts, it is possible to determine the values ​​of the gravitational electrical interaction of material bodies under conditions of gravity. To do this, consider the following model. Any material energy body while in electric field, will carry out a certain Coulomb interaction. Depending on the internal organization of the electric charge, it will either be attracted to one of the electric poles, or be in a state of equilibrium within this field. The degree of electrical charge of each body is determined by its own concentration of free electrons (for humans, the concentration of red blood cells). Then the model of gravitational interaction of earth's attraction can be represented in the form of a spherical capacitor consisting of two concentric hollow spheres, the radii of which are determined by the radius of the Earth and the height of the ionospheric layer F2. There is a person or another material body in this electric field. The electric charge of the Earth's surface is negative, the ionosphere is positive in relation to the Earth. The electric charge of a person in relation to the surface of the Earth is positive, therefore, the Coulomb force of interaction on the surface will always attract a person to the Earth. The presence of ionospheric layers implies that the total electrical capacitance of such a capacitor is determined by the total capacitance of each layer when connected in series: 1/Tot = 1/C(E)+1/C(F)+1/C(F2). Since an approximate engineering calculation is being carried out, we will take into account the main energy ionospheric layers, for which we will take the following initial data: layer E - height 100 km, layer F - height 200 km, layer F2 - height 400 km. Consideration of the D layer and the sporadic Es layer formed in the ionosphere during the process of increased or decreased solar activity, for simplicity of consideration we will not take into account. In Fig. Figure 1 shows a diagram of the distribution of the ionospheric layers of the Earth’s atmosphere and an electrical circuit diagram of the process under consideration.
The electrical circuit in Fig. 1.a shows a series connection of three capacitors, to which a constant voltage Etotal is supplied. In accordance with the laws of electrostatics, the distribution electric charges on the plates of each capacitor C1, C2 and C3 it is shown conditionally +/-. Based on this distribution of electric charges, local field strengths arise in the network, the directions of which are opposite to the overall applied voltage. In these sections of the network, the movement of electric charges will be in the opposite direction, relative to the Total. Figure 1.b shows a diagram of the ionospheric layers of the Earth's atmosphere, which is completely described by an electrical circuit serial connection capacitors. The Coulomb interaction forces between ionospheric layers are designated as Fg. According to the level of concentration of electric charges, the upper layer of the F2 ionosphere is electrically positive with respect to the earth's surface. Due to the fact that solar wind particles with different kinetic energies penetrate the entire depth of the atmosphere, the total force of the Coulomb interaction of each layer will be determined by the vector sum of the total gravitational force Fg total and the gravitational force of a separate ionospheric layer. The formula for calculating the capacitance of a spherical capacitor is: C = 4x(pi)x e(a)x r1xr2/(r2-r1), where C is the capacitance of the spherical capacitor; r1 is the radius of the inner sphere, equal to the sum of the radius of the Earth 6,371.0 km and the height of the lower ionospheric layer; r2 is the radius of the outer sphere, equal to the sum of the radius of the Earth and the height of the upper ionospheric layer; e(a)=e(0)x e -absolute permittivity, where e(0)=8.85x10(-12) fm, e ~ 1. Then the rounded calculated values ​​for the capacitance of each ionospheric layer will have the following values: C(E)=47 μF, C(F)=46 μF, C(F2)=25 µF. The total total capacity of the ionosphere, taking into account the main layers, will be about 12 μF. The distance between the ionospheric layers is much less than the radius of the Earth, therefore, the calculation of the Coulomb force acting on the charge can be carried out using the formula of a flat capacitor: Fg= e(a) x A x U(2) /(2xd(2)), where A is the area plates (pi x (Rз+ h)(2)); U - voltage; d - distance between layers; e(a)=e(0)x e - absolute dielectric constant, where e(0)=8.85x10(-12) fm, e ~ 1. Then the calculated values ​​of the Coulomb interaction forces of each ionospheric layer will have the following values: Fg (E)= 58x10(-9)x U(2); Fg(F)= 59x10(-9)x U(2); Fg(F1)= 15x10(-9)x U(2); Fgtot = 3.98x10(-9)x U(2). Let us determine the value of atmospheric stress for a body weighing 100 kg. The calculation formula will have the following form: F=m x g= Fg(E) + Fgtot. Substituting known values into this formula, we get the value U = 126 kV. Consequently, the forces of Coulomb interaction of ionospheric layers will be determined by the following values: Fg(E)= 920n; Fg(F)= 936n; Fg(F1)= 238n; Fgtotal= 63n. Having recalculated the free fall acceleration of each ionospheric layer, taking into account the Newtonian interaction, we obtain the following values: g(E)= +9.83 m/s(2); g(F)= -8.73 m/s(2); g(F1)= - 1.75 m/s(2). It should be noted that these calculated values ​​do not take into account the intrinsic parameters of the atmosphere, namely the pressure and resistance of the environment, caused by the concentration of oxygen and nitrogen molecules in each layer of the ionosphere. As a result of an approximate engineering calculation, the obtained value g(F1) = -1.75 m/s(2) which is in good agreement with the actual value of local gravity on the ISS - 10(−3)...10(−1) g. The discrepancies in the results are due to the fact that the torsion balance used to measure the acceleration of gravity is not calibrated to the area negative values- modern science did not expect this. To create artificial gravity, two conditions must be met. Create an electrically isolated system in accordance with the requirement of Gauss’s theorem, namely, ensure the circulation of the electric field strength vector in a closed sphere and provide inside this sphere the electric field strength necessary to create a Coulomb interaction force of 1000 N. The field strength can be calculated using the formula: F= e(a) x A x E(2) /2, where A is the area of ​​the plate; E - electric field strength; e(a)=e(0)x e - absolute dielectric constant, where e(0)=8.85x10(-12) fm, e ~ 1. Substituting the data into the formula, for 10 sq.m we obtain the value of the electric field strength , equal to E = 4.75 x 10(6) V/m. If the height of the room is three meters, then to ensure the calculated voltage it is necessary to apply a constant voltage to the floor-ceiling with a value of U = E x d = 14.25 MV. With a current of 1 A, it is necessary to ensure a resistance of the plates of such a capacitor of 14.25 MOhm. By changing the voltage, you can get different gravity parameters. The order of the calculated values ​​shows that the development of artificial gravity systems is real deal. The ancient Greeks were right: “Looking at the world, open your eyes...”. Only such an answer can be given regarding the nature of earth's gravity. For 200 years now, humanity has been actively studying the laws of electrostatics, including Coulomb’s law and Gauss’s theorem. The formula for a spherical capacitor has been practically mastered for a long time. All that remains is to open your eyes to the world around us and begin to use it to explain the seemingly impossible. But when we all understand that artificial gravity is a reality, then the questions commercial use space flights will become relevant and will be transparent for understanding.
Moscow, April 2011 Brazhnik G.N.

Even if you're not particularly interested in space, chances are you've seen it in movies, read about it in books, or played games where space is a prominent theme. At the same time, in most of the works there is one point that, as a rule, is taken for granted - gravity on a spaceship. But is it as simple and obvious as it seems at first glance?

First, a little hardware. If you don’t delve into physics beyond the school course (and that will be quite enough for us today), then gravity is the fundamental interaction of bodies, thanks to which they all attract each other. More massive ones attract stronger, less massive ones attract weaker.

Materiel

In our case, the following is important. The Earth is a massive object, so people, animals, buildings, trees, blades of grass, the computer you are reading this from are all attracted to the Earth. We are used to this and actually never think about such seemingly trifles. The main consequence of the Earth's gravity for us is acceleration of gravity, also known as g, and equal to 9.8 m/s². Those. any body in the absence of support will equally accelerate towards the center of the Earth, gaining 9.8 m/s speed every second.

It is thanks to this effect that we can stand straight on our feet, have the concepts of “up” and “down,” drop things on the floor, etc. In fact, many types of human activity would be greatly modified if the Earth's gravity were removed.

This is best known to astronauts who spend a significant part of their lives on the ISS. They have to relearn how to do a lot of things, from how they drink to how they go for various physiological needs. Here are some examples.

At the same time, in many films, TV series, games and other works of Sci-Fi art, gravity on spaceships “simply exists.” They take it for granted and often don’t even bother to explain it. And if they do explain it, it’s somehow unconvincing. Something like “gravity generators”, the operating principle of which is a little more mystical than completely, so in fact this approach differs little from “gravity on a ship” just there" It seems to me that not explaining at all is somehow more honest.

Theoretical models of artificial gravity

But all this does not mean that no one is trying to explain artificial gravity at all. If you think about it, you can achieve it in several ways.

Lots of mass

The first and most “correct” option is to make the ship very massive. This method can be considered “correct” because it is the gravitational interaction that will provide the necessary effect.

At the same time, the unreality of this method, I think, is obvious. For such a ship you will need a lot of material. And with the distribution of the gravitational field (and we need it to be uniform), something will need to be decided.

Constant acceleration

Since we need to achieve a constant gravitational acceleration of 9.8 m/s², why not make the spacecraft in the form of a platform that will accelerate perpendicular to its plane with this same g? In this way, the desired effect will undoubtedly be achieved.

But there are a few obvious problems. First, you need to get fuel from somewhere to ensure constant acceleration. And even if someone suddenly comes up with an engine that does not require the emission of matter, no one has canceled the law of conservation of energy.

The second problem is the very nature of constant acceleration. Firstly, according to our current understanding of physical laws, it is impossible to accelerate forever. The theory of relativity is strongly opposed. Secondly, even if the ship changes direction periodically, to provide artificial gravity it will constantly need to fly somewhere. Those. There can be no talk of any hovering near planets. The ship will be forced to behave like a shrew, which if it stops, it will die. So this option does not suit us.

Carousel carousel

And here is where the fun begins. I am sure that each of the readers can imagine how the carousel works and what effects a person in it can experience. Everything that is on it tends to jump out in proportion to the speed of rotation. From the point of view of the carousel, it turns out that everything is affected by a force directed along the radius. Quite a “gravity” thing.

So we need a barrel-shaped ship that will rotate around its longitudinal axis. Such options are quite common in science fiction, so the world of Sci-Fi is not so hopeless in terms of explaining artificial gravity.

So, a little more physics. When rotating around an axis, a centrifugal force is generated directed along the radius. As a result of simple calculations (dividing the force by mass), we obtain the desired acceleration. This whole thing is calculated according to a simple formula:

a=ω²R,

Where a— acceleration, R- radius of rotation, a, ω - angular velocity, measured in radians per second. A radian is approximately 57.3 degrees.

What do we need to get for a normal life on our imaginary space cruiser? We need such a combination of the ship's radius and angular velocity that their product results in a total of 9.8 m/s².

We could see something similar in many works: "2001: A Space Odyssey" Stanley Kubrick, series "Babylon 5", Nolan's « » , novel "Ring World" Larry Niven, Universe and others. In all of them, the acceleration of gravity is approximately equal g, so everything turns out quite logical. However, these models also have problems.

Problems in the "carousel"

The most obvious problem is perhaps easiest to explain in "Space Odyssey". The radius of the ship is approximately 8 meters. Using simple calculations, we find that to achieve an acceleration equal to g, an angular velocity of approximately 1.1 rad/s is required, which is equal to approximately 10.5 revolutions per minute.

With these parameters, it turns out that Coriolis effect. If you don't go deep into technical details, then the problem is that at different “heights” from the floor, different forces will act on moving bodies. And it depends on the angular velocity. So in our virtual design, we cannot afford to rotate the ship too quickly, as this is fraught with problems, ranging from sudden, unintuitive falls to problems with the vestibular system. And taking into account the above-mentioned acceleration formula, we cannot afford a small radius of the ship. Therefore, the space odyssey model is no longer needed. About the same problem with ships from "Interstellar", although with the numbers everything is not so obvious.

The second problem is on the other side of the spectrum, so to speak. In the novel Larry Niven "Ring World" the ship is a giant ring with a radius approximately equal to the radius of the earth's orbit (1 AU ≈ 149 million km). Thus, it turns out that it rotates at a quite satisfactory speed so that the Coriolis effect is invisible to humans. Everything seems to fit, but there is one thing But. To create such a structure, you will need an incredibly strong material that will have to withstand enormous loads, because one revolution should take about 9 days. Mankind does not know how to ensure sufficient strength of such a structure. Not to mention the fact that somewhere you need to take so much matter and build the whole thing.

Ring World

In the case of Halo or "Babylon 5" all previous problems seem to be absent. And the rotation speed is sufficient so that the Coriolis effect does not have a negative impact, and it is, in principle, possible to build such a ship (at least theoretically). But these worlds also have their drawbacks. Its name is angular momentum.

Station from Babylon 5

By spinning the ship around its axis, we turn it into a giant gyroscope. And it is known to be quite difficult to deflect a gyroscope from its axis. All precisely because of the angular momentum, the amount of which must be conserved in the system. This means that flying somewhere in a certain direction will be difficult. But this problem can also be solved.

How it should be

This solution is called "O'Neill's cylinder". Its design is quite simple. We take two identical cylinder ships connected along an axis, each of which rotates in its own direction. As a result, we have zero total angular momentum, which means there should be no problems with directing the ship in the desired direction. With a ship radius of approximately 500 m (like in Babylon 5) or more, everything should work as it should.

Total

So, what conclusions can we draw about how artificial gravity should be implemented in spacecraft? Of all the implementations that are proposed in various kinds of works, the most realistic one is the rotating structure, in which the force directed “down” is provided by centripetal acceleration. Create artificial gravity on a ship with flat parallel structures like decks (as is often depicted in various Sci-Fi), taking into account our modern understandings laws of physics, it is not possible

The radius of the spinning ship must be sufficient that the Coriolis effect is small enough to not affect humans. Good examples from imaginary worlds are those already mentioned Halo And Babylon 5.

To control such ships, you need to build an O’Neill cylinder - two “barrels” rotating in different directions to provide zero total angular momentum for the system. This will allow adequate control of the ship.

In total, we have a very realistic recipe for providing astronauts with comfortable gravitational conditions. And until we can actually build something like this, I would like the creators of games, films, books and other works about space to pay more attention to physical realism.

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Weightlessness negatively affects the human body. Thus, one of the consequences of its impact is the rapid atrophy of muscles and the subsequent decrease in all physical indicators body. To solve this problem, special simulators are installed on the ISS, on which astronauts train for several hours a day. But simulators are boring; it would be much more interesting to create artificial gravity.

One of the ways to create artificial gravity, which is constantly recalled in the works of science fiction writers and scientists, is to create a space station that would rotate around its axis. Such rotation would result in the astronauts or station residents being constantly affected by a centrifugal force, which they would feel as a gravitational force. There are a lot of similar projects; to quickly get an idea of ​​what kind of stations these are, you can read several small articles from Wikipedia: this one, this one and this one.

Rotating station from the inside. Source: Wikipedia Commons

Why are these solutions not applied in practice? Let's try to figure it out.

The idea of ​​artificial gravity due to rotation is based on the principle of equivalence between the force of gravity and the force of inertia; which states: if the inertial mass and gravitational mass are equal, then it is impossible to distinguish which force acts on the body - gravitational or inertial force. In simple words: if you create a spacecraft rotating around its axis, the resulting centrifugal force will “push” the astronaut into side away from the center of rotation, and he can easily stand on the “floor”. The faster the ship rotates, and the farther from the center the astronaut is, the stronger the artificial gravity will be. The force of attraction F will be equal to:

F = m*v 2 /r, Where m- mass of the astronaut, v— linear speed of the astronaut, r— distance from the center of rotation (radius).

The linear speed is equal to v = 2π*R/T, Where T- time of one revolution.

Let's see what problems the developers of a rotating station may encounter.

As you can see, the artificial force of attraction directly depends on the distance from the center of rotation, it turns out that for small r the force of gravity will be significantly different for the astronaut's head and legs, which can make movement very difficult. But it will be possible to adapt to this.

It is much more difficult to adapt to the effects of the Coriolis force, which will occur every time our astronaut moves relative to the direction of rotation (Coriolis Force, Wikipedia). Under the influence of this force, the astronaut will be constantly motion sick, and this is not so fun. To get rid of this effect, the rotation speed of the station must be equal to two revolutions per minute or less, and here another problem arises - at a rotation frequency of two revolutions per minute, to obtain artificial gravity of 1g (as on Earth), the radius of rotation must be equal to 224 meters. Imagine a space station in the form of a cylinder with a diameter of almost half a kilometer! Of course it is possible to build, but it will be very difficult and very, very expensive.

However, efforts to begin work in this direction are already underway. So in 2011 NASA proposed a project space station, one of the modules of which will rotate, providing artificial gravity of 0.11-0.69g. The project was called "Nautilus-X". The diameter of the rotating module will be 9.1 or 12 meters, and the module itself will serve as a sleeping place for 6 astronauts.

The station is planned to be used as an intermediate base for long-distance space flights. One of the stages of the project is testing the rotating part on the ISS, which will cost NASA $150 million and three years of work. The construction of an entire station according to the Nautilus-X project will cost about 4 billion.

Spaceships with artificial gravity are just around the corner, guys!