Although the construction of a space elevator is already within our engineering capabilities, the passions around this structure have unfortunately subsided recently. The reason is that scientists have not yet been able to obtain the technology to produce carbon nanotubes of the required strength on an industrial scale.

The idea of ​​launching cargo into orbit without rockets was proposed by the same person who founded theoretical cosmonautics - Konstantin Eduardovich Tsiolkovsky. Inspired by the Eiffel Tower he saw in Paris, he described his vision of a space elevator in the form of a tower of enormous height. Its top would just be in a geocentric orbit.

The elevator tower is based on strong materials that prevent compression - but modern ideas for space elevators still consider a version with cables that must be tensile strength. This idea was first proposed in 1959 by another Russian scientist, Yuri Nikolaevich Artsutanov. First scientific work with detailed calculations for a space elevator in the form of a cable, was published in 1975, and in 1979 Arthur C. Clarke popularized it in his work “The Fountains of Paradise.”

Although nanotubes in this moment recognized as the strongest material, and the only one suitable for building an elevator in the form of a cable pulled from a geostationary satellite, the strength of nanotubes obtained in the laboratory is not yet enough to reach the calculated strength.

Theoretically, the strength of nanotubes should be more than 120 GPa, but in practice the highest elongation of a single-walled nanotube was 52 GPa, and on average they broke in the range of 30-50 GPa. A space elevator requires materials with a strength of 65-120 GPa.

Late last year, the largest American documentary film festival, DocNYC, screened the film Sky Line, which describes the attempts of US engineers to build a space elevator - including participants in the NASA X-Prize competition.

The main characters of the film are Bradley Edwards and Michael Lane. Edwards is an astrophysicist who has been working on the space elevator idea since 1998. Lane is an entrepreneur and founder of LiftPort, a company promoting the commercial use of carbon nanotubes.

In the late 90s and early 2000s, Edwards, having received grants from NASA, intensively developed the idea of ​​​​a space elevator, calculating and evaluating all aspects of the project. All his calculations show that this idea is feasible - if only a fiber strong enough for the cable appears.

Edwards briefly partnered with LiftPort to seek funding for the elevator project, but due to internal disagreements, the project never materialized. LiftPort closed in 2007, although a year earlier it had successfully demonstrated a robot climbing a mile-long vertical cable suspended from balloons as part of a proof of concept for some of its technology.

That private space, concentrating on reusable rockets, could completely supplant space elevator development in the foreseeable future. According to him, the space elevator is attractive only because it offers cheaper ways to deliver cargo into orbit, and reusable rockets are being developed precisely to reduce the cost of this delivery.

Edwards blames the stagnation of the idea on the lack of real support for the project. “This is what projects look like that hundreds of people scattered around the world develop as a hobby. No serious progress will be made until there is real support and centralized control."

The situation with the development of the idea of ​​a space elevator in Japan is different. The country is famous for its developments in the field of robotics, and Japanese physicist Sumio Iijima is considered a pioneer in the field of nanotubes. The idea of ​​a space elevator is almost national here.

Japanese company Obayashi vows to deliver a working space elevator by 2050. The company's chief executive, Yoji Ishikawa, says they are working with private contractors and local universities to improve existing nanotube technology.

Ishikawa says that although the company understands the complexity of the project, they do not see any fundamental obstacles to its implementation. He also believes that the popularity of the idea of ​​a space elevator in Japan is caused by the need to have some kind of national idea that unites people against the backdrop of difficult times. economic situation the last couple of decades.

Ishikawa is confident that although an idea of ​​this magnitude can most likely only be realized by international cooperation, Japan may well become its locomotive due to the great popularity of the space elevator in the country.

Meanwhile, Canadian space and defense company Thoth Technology US No. 9085897 for their space elevator variant. More precisely, the concept involves the construction of a tower that retains its rigidity thanks to compressed gas.

The tower should deliver cargo to a height of 20 km, from where they will be launched into orbit using conventional rockets. This intermediate option, according to the company’s calculations, will save up to 30% of fuel compared to a rocket.

A ride on a space elevator will probably be reminiscent of a hot air balloon flight - without the roar of nozzles, without a plume of furious flame. The Earth goes down smoothly. Houses are becoming smaller, roads are turning into barely noticeable threads, and the silvery ribbons of rivers are thinning. Finally, the lower, vain world is hidden in the clouds and the upper, transcendental world is revealed. The atmosphere has passed, behind the glass there is cosmic blackness. And the cabin slides higher and higher along a cable, invisible against the blue-green background of the planet and going into the bottomless void.

Tsiolkovsky also described a design that could connect the orbit with the surface of the Earth. In the early 1960s, the idea was developed by Yuri Artsutanov, and Arthur Clarke used it in the novel The Fountains of Paradise. “World of Fantasy” returns to the theme of the space elevator and tries to imagine how it should work and what is needed for it.

Geostationary orbit

Is it possible for a satellite to freeze motionless above the observer's head? If the Earth were motionless, as in the Ptolemaic system of the world, the answer would be “no” - after all, without centrifugal force, the satellite would not stay in orbit. But, as we know, the observer himself is not motionless, but rotates along with the planet. If the satellite’s orbital period is equal to a sidereal day (23 hours 56 minutes 4 seconds), and its orbit is in the equatorial plane, the device will hover over the so-called “standing point.”

The orbit in which the satellite is stationary relative to its stationary point is called geostationary. And it is extremely important for space exploration. It is where most communications satellites are located, and communications are the main area of ​​commercial use of space. Transmissions through a repeater hanging above the equator can be received on stationary “plates”.

There is also an idea to place a manned station in geostationary orbit. For what? Firstly, for the maintenance and repair of communication satellites. In order for satellites to serve for several more years, it is often only necessary to refuel the micromotors that ensure the orientation of the solar panels and antenna. The manned station will be able to maneuver along the geostationary orbit, descend (at the same time its angular velocity will become higher than that of the “standing” satellites), catch up with the vehicle requiring maintenance and rise again. This will take no more fuel than a low-orbit station consumes when it overcomes friction with the rarefied atmosphere.

It would seem that the benefit is huge. But supplying such a remote outpost would be too expensive. Changing crews and sending transport ships will require launch vehicles five times heavier than those currently used. A much more attractive idea is to use a high-altitude station to build a space elevator.

Cables

What will happen if a cable is thrown down from a geostationary satellite towards the Earth? First, the Coriolis force will carry him forward. After all, it will receive the same speed as the satellite, but will be in a lower orbit, which means its angular speed will be higher. But after a while the cable will gain weight and hang vertically. The radius of rotation will decrease and the centrifugal force will no longer be able to balance the force of gravity. If you continue to etch the rope, sooner or later it will reach the surface of the planet.

To prevent the system's center of gravity from shifting, a counterweight is needed. Some people suggest using spent satellites or even a small asteroid as ballast. But there is a more interesting option - to etch the cable in the opposite direction, from the Earth. It will also straighten and stretch. But no longer under own weight, but due to centrifugal force.

The second cable will be more useful than simple ballast. Cheap, rocket-free delivery of cargo into geostationary orbit is useful, but in itself will not pay for the cost of the elevator. The station at an altitude of 36,000 kilometers will become only a transfer point. Further, without energy consumption, accelerated by centrifugal force, the loads will move along the second cable. At a distance of 144,000 kilometers from Earth, their speed will exceed the second cosmic speed. The elevator will turn into a catapult, sending projectiles to the Moon, Venus and Mars using the energy of the planet’s rotation.

The problem is the cable, which must not break under its own weight, despite its fantastic length. With a steel rope, this will happen already at a length of 60 kilometers (and possibly much earlier, since defects are inevitable during weaving). You can avoid breaking if the thickness of the rope increases exponentially with height - after all, each subsequent section must withstand its own weight plus the weight of all previous ones. But the thought experiment will have to be interrupted: closer to the upper end, the cable will reach such a thickness that the iron reserves in the earth’s crust are simply not enough for it.

Even the strongest polyethylene “Dyneema”, from which body armor and parachute lines are made, is not suitable. It has a low density, with a cross-section of one square millimeter it can withstand a load of two tons and breaks under its own weight only at a length of 2500 kilometers. But the Dainima cable must have a mass of about 300,000 tons and a thickness of 10 meters at the upper end. It is almost impossible to deliver such cargo into orbit, and the elevator can only be built from above.

Hope is given by carbon nanotubes discovered in 1991, which are theoretically capable of being 30 times stronger than Kevlar (in practice, polyethylene rope is still stronger). If optimistic estimates of their potential are confirmed, it will be possible to produce a tape with a constant cross-section of 36,000 km in length, weighing 270 tons and carrying capacity of 10 tons. And if even pessimistic estimates are confirmed, an elevator with a cable 1 millimeter thick near the Earth and 25 centimeters in orbit (mass 900 tons without taking into account the counterweight) will no longer be science fiction.

Lift

Creating a lift for a space elevator is a non-trivial task. To make a cable, you just need to develop a new technology. A mechanism capable of climbing this cable and delivering cargo into orbit has yet to be invented. The “earthly” method, when the cabin is attached to a rope wound on a drum, does not stand up to criticism: the mass of the load will be negligible compared to the mass of the rope. The lift will have to climb on its own.

It would seem that this is not difficult to implement. The cable is clamped between the rollers, and the machine creeps up, held by friction. But this is only in science fiction a space elevator - a tower or a mighty column within which the cabin moves. In reality, a barely visible thread will reach the surface of the Earth, at best: a narrow ribbon. The contact area of ​​the rollers with the support will be negligible, which means that the friction cannot be great.

There is one more limitation - the mechanism must not damage the cable. Alas, although nanofabric is incredibly tear-resistant, this does not mean that it is difficult to cut or fray. Replacing a broken cable will be very difficult. And if it bursts at a high altitude, the centrifugal force will carry the station far into space, ruining the entire project. In order to maintain the system’s center of gravity in orbit in an emergency, small mines will have to be placed along the entire length of the cable. If one of the branches breaks, they will immediately shoot off an equal part of the opposite branch.

There are a lot of other interesting problems that need to be solved. For example, the divergence of lifts moving towards each other and the rescue of passengers from “stuck” cabins.

The most difficult problem is power supply to the lift. The engine will require a lot of energy. The capacity of batteries, both existing and those being developed, is not enough. The supply of chemical fuel and oxidizer will turn the lift into a multi-stage system of tanks and engines. This wonderful design, by the way, does not need an expensive cable - it exists right now and is called a “booster rocket”.

The easiest way is to build contact wires into the cable. But the cable will not withstand the weight of the metal wiring, which means that the nanotubes will have to be “taught” to conduct electric current. Autonomous power supply in the form of solar panels or a radioisotope source is rather weak: according to the most optimistic estimate, the rise with them will take decades. A nuclear reactor with a better mass-to-power ratio would take years to get the cabin into orbit. But it itself is too heavy and will also require two or three refuelings along the way.

Perhaps the best option is to transfer energy using a laser or microwave gun, irradiating the receiving device of the elevator. But it is not without its shortcomings. At the current level of technology, only a minority of the energy received can be converted into electricity. The rest will turn into heat, which will be very problematic to remove in an airless space.

If a cable becomes damaged, it will be difficult to get repairmen to the damaged area. And if it breaks, it’s too late (frame from the game Halo 3: ODST)

Radiation protection

Bad news for those who want to ride light: the elevator will pass through the Earth's radiation belts. The planet's magnetic field captures solar wind particles - protons and electrons - and prevents dangerous radiation from reaching the surface. As a result, the Earth is surrounded in the equatorial plane by two colossal tori, inside of which charged particles are concentrated. Even spacecraft try to avoid these areas.

The first belt, the proton trap, begins at an altitude of 500–1300 kilometers and ends at an altitude of 7000 kilometers. Behind it, up to an altitude of approximately 13,000 kilometers, there is a relatively safe area. But even further, between 13 and 20 thousand kilometers, the outer radiation belt of high-energy electrons extends.

Orbital stations rotate below the radiation belts. Manned spacecraft crossed them only during lunar expeditions, spending only a few hours on it. But the lift will need about a day to overcome each of the belts. This means that the cabin will have to be equipped with serious anti-radiation protection.

Mooring tower

The base of a space elevator is usually imagined as a complex of above-ground structures located somewhere in Ecuador, the jungles of Gabon, or an atoll in Oceania. But the most obvious solution is not always the best. Once released from orbit, the tether can be secured to the deck of a ship or to the top of a colossal tower. The sea vessel will evade hurricanes, which can, if not break off the elevator, which has considerable windage, then throw off the lifts from it.

A tower 12-15 kilometers high will protect the cable from the violence of the atmosphere, and will also somewhat shorten its length. At first glance, the benefit seems insignificant, but if the mass of the cable depends exponentially on its length, then even a tiny gain will achieve noticeable savings. In addition, the mooring tower makes it possible to approximately double the system's carrying capacity by eliminating the thinnest and most vulnerable section of the thread.

However, it is possible to erect a building of such height only on the pages of science fiction novels. Theoretically, such a tower can be built from a material with the hardness of diamond. In practice, no foundation will support its weight.

Nevertheless, it is possible to build a mooring tower at a height of many kilometers. Only building material It is not concrete that should serve, but gas: helium-filled balloons. Such a tower will be a “float”, the lower part of which is immersed in the atmosphere and, due to the Archimedean force, supports the upper part, which is already in an almost airless space. This structure can be built from below, from individual, small-sized and completely replaceable blocks. There are no fundamental obstacles to the “inflatable tower” reaching a height of 100 or even 160 kilometers.

Even without a space elevator, a "floating tower" makes sense. Like a power plant - if outer shell cover with solar panels. Like a repeater serving an area with a radius of one and a half thousand kilometers. Finally, as an observatory and base for studying the upper layers of the atmosphere.

And if you don’t aim for a height of hundreds of kilometers, you can use a ring-shaped balloon “anchored” at an altitude of 40 kilometers as a berthing station. A giant airship (or several airships located one above the other) will unload the elevator cable, taking on its weight in the last tens of kilometers.

But the most significant advantages would come from a moving platform in the form of a high-altitude airship flying over the equator at a speed of 360 km/h (which is quite achievable when the engine is powered by solar panels and a nuclear reactor). In this case, the satellite does not need to hover over one point. Its orbit will be located 7,000 kilometers below the geostationary one, which will reduce the cable length by 20% and the mass by 2.5 times (taking into account the benefits from the use of the “mooring tower”). It remains to solve the problem of delivering cargo to the airship itself.

Gravity catapult

The space elevator is the most ambitious, but not the only project to use tethers to launch spacecraft. Some other plans can be realized at the current level of technology.

What, for example, will happen if a load tied by a cable is pushed “up” from the shuttle hanging in orbit, away from the Earth? According to the law of conservation of momentum, the ship itself will shift to a lower orbit. And it will start to fall. The load, dragging the unwinding cable along with it, will first be deflected backward by the Coriolis force, but then rush “up”. Indeed, with an increase in the radius of rotation, gravity will weaken, and the centrifugal force will increase. The system will work like a trebuchet - an ancient throwing machine. The shuttle will take on the role of the cage with stones, the cable will turn into a sling, and the axis will be the general center of mass of the system, which is in a state of weightlessness in the initial orbit of the ship. Having swung relative to the axis, the cable will straighten in the vertical direction, stretch and throw out the load.

The difference between a gravitational catapult and a space elevator is that the role of the “cage” in the elevator is played by the planet itself, “falling” to an indistinguishably small height relative to the center of mass of the “Earth-projectile” system. In this case, the kinetic energy of the shuttle will be spent. The ship will transfer part of its momentum to the cargo - say, an automatic interplanetary station - will lose speed and altitude and enter the dense layers of the atmosphere. Which is also good, since usually in order to deorbit the shuttle has to be slowed down by its engines, burning fuel.

With the help of a cable catapult, the shuttle will be able to send 2-3 times more cargo to Mars or Venus than in the traditional way. Which, however, still will not allow the shuttle system to compete with a conventional launch vehicle in terms of efficiency. After all, for a “catapult” launch it will be necessary to launch not only the payload, but also a gigantic cable with a “counterweight” into orbit. Another thing is that the counterweight for the catapult can be found directly in orbit - for example, a transport ship that has completed its mission will do. In addition, there is a mass of “space debris” revolving around our planet, which will have to be collected in the foreseeable future.

* * *

The problems associated with the construction of a space elevator are far from resolved. A cost-effective alternative to rockets and shuttles will not appear soon. But at the moment, the “staircase to the void” is the most fantastic and large-scale project that science is working on. Even if the structure, whose length is a dozen times the diameter of the planet, turns out to be ineffective, it will mark the beginning of a new stage in human history. The same “exit from the cradle” that Konstantin Eduardovich Tsiolkovsky spoke about more than a century ago.

IV Interregional Conference of Schoolchildren

"Road to the Stars"

Space elevator - fiction or reality?

Completed:

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Supervisor:

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Yaroslavl

Introduction

Space elevator ideas by K.E. Tsiolkovsky, Yu.N. Artsutanova, G.G. Polyakova

Space elevator design

Description of modern projects

Conclusion

Introduction

In 1978, Arthur C. Clarke’s science fiction novel “The Fountains of Paradise” was published, dedicated to the idea of ​​​​building a space elevator. The action takes place in the 22nd century on the non-existent island of Taproban, which, as the author points out in the preface, corresponds 90% to the island of Ceylon (Sri Lanka).

Often science fiction writers predict the appearance of an invention not of their own century, but of a much later time.

What is a space elevator?

A space elevator is a concept of an engineering structure for launching cargo into space without rockets. This hypothetical design is based on the use of a cable stretched from the surface of the planet to an orbital station located in GEO. For the first time such an idea was expressed by Konstantin Tsiolkovsky in 1895; the idea was developed in detail in the works of Yuri Artsutanov.

The purpose of this work is to study the possibility of building a space elevator.

Space elevator ideas by K.E. Tsiolkovsky, Yu.N. Artsutanov and G.G. Polyakova

Konstantin Tsiolkovsky - Russian and Soviet self-taught scientist and inventor, school teacher. Founder of theoretical cosmonautics. Justified the use of rockets for space flights, came to the conclusion about the need to use " rocket trains" - prototypes of multistage rockets. His main scientific works relate to aeronautics, rocket dynamics and astronautics.

Representative of Russian cosmism, member of the Russian Society of World Studies Lovers. Author of science fiction works, supporter and propagandist of the ideas of space exploration. Tsiolkovsky proposed populating outer space using orbital stations. He believed that the development of life on one of the planets of the Universe would reach such power and perfection that this would make it possible to overcome the forces of gravity and spread life throughout the Universe.

In 1895, Russian scientist Konstantin Eduardovich Tsiolkovsky was the first to formulate the concept and concept of a space elevator. He described a free-standing structure extending from ground level to geostationary orbit. Rising 36 thousand kilometers above the equator and following the direction of the Earth's rotation, at the end point with an orbital period of exactly one day, this structure would remain in a fixed position.

YU
Riy Nikolaevich Artsutanov is a Russian engineer born in Leningrad. Graduate of Leningradsky

Institute of Technology, is known as one of the pioneers of the space elevator idea. In 1960, he wrote the article "To Space - by Electric Locomotive", where he discussed the concept of a space elevator as a cost-effective, safe and convenient way to access orbit to facilitate space exploration.

Yuri Nikolaevich developed the idea of ​​​​Konstantin Tsiolkovsky. Artsutanov's concept was based on linking geosynchronous satellites with a cable to the Earth. He proposed using the satellite as a base from which to build the tower, since the geosynchronous satellite would remain above a fixed point on the equator. With the help of a counterweight, the cable will be lowered from geosynchronous orbit to the surface of the Earth, while the counterweight will move away from the Earth, keeping the center of mass of the cable stationary relative to the Earth.

A Rtsutanov proposed fastening one end of such a “rope” to the earth’s equator, and attaching a balancing weight to the second end, located far beyond the planet’s atmosphere. If the “rope” was long enough, the centrifugal force would exceed the force of gravity and prevent the load from falling to the Earth. From the calculations given by Artsutanov, it follows that the force of attraction and centrifugal force are equal at an altitude of about 42,000 kilometers. The resultant of these forces, equal to zero, reliably fixes the “stone” at the zenith.

Now sealed electric locomotives will run vertically upward - towards orbit. A smooth increase in speed and smooth braking will help to avoid overloads characteristic of a rocket liftoff. After several hours of traveling at a speed of 10 - 20 kilometers per second, the first stop will follow - at the equinox point, where the transshipment station spread out in zero gravity will open the doors of bars, restaurants, lounges - and a wonderful view of the Earth from the windows.

After stopping, the cabin will not only be able to move without wasting energy, since it will be thrown away from the Earth by centrifugal force, but also, in addition, the engine, switched to dynamo mode, will generate the electricity necessary to return.

The second and final stop was proposed to be made at a distance of 60,000 kilometers from the Earth, where the resultant forces would be equal to the force of gravity on the earth’s surface, and would allow the creation of artificial gravity at the “final station”. Here, on the edge of the longest cable car, a real orbital spaceport will be located. He, as expected, will launch spaceships across the Solar System, giving them a respectable speed and assigning a trajectory.

Not wanting to limit himself to a primitive rope, Yuri Artsutanov hung on it solar power plants that convert solar energy into electric current, and solenoids that generate an electromagnetic field. An “electric locomotive” must move in this field.

If we estimate the weight of such a magnetic road surface, taking into account the length of 60,000 kilometers, then it turns out - hundreds of millions of tons? Much more. More than one thousand rockets will be required to tow this weight to orbit! At the time it seemed impossible.

However, this time the scientist came up with the right idea: the elevator does not have to be built from the bottom up, like a huge cyclopean tower - it is enough to launch an artificial satellite into geostationary orbit, from which the first thread will be lowered. In cross-section, this thread will be thinner than a human hair, so that its weight does not exceed a thousand tons. After the free end of the thread is secured to the earth's surface, a “spider” will run from top to bottom along the thread - a light device that weaves a second, parallel thread. It will work until the rope is thick enough to support the "electric locomotive", the electromagnetic sheet, solar power plants, rest rooms and restaurants.

It is quite understandable why, in the era of space races, the idea of ​​Yuri Valerievich Artsutanov remained unnoticed by anyone. At that time there was no material capable of withstanding such a high breaking pressure of the cable.

In development of Artsutanov’s ideas, Georgy Polyakov from the Astrakhan Pedagogical Institute proposed his space elevator project in 1977.

Fundamentally, this elevator is almost no different from the one described above. Polyakov only points out: a real space elevator will be much more complicated than the one described by Artsutanov. In fact, it will consist of a series of simple elevators of successively decreasing lengths. Each is a self-balanced system, but only thanks to one of them reaching the Earth, the stability of the entire structure is ensured.

The length of the elevator (approximately 4 times the diameter of the Earth) was chosen in such a way that the apparatus, separated from its top, would be able to move by inertia into outer space. At the top point there will be a launch point for interplanetary spacecraft. And ships returning from a flight, having previously entered a stationary orbit, “lift” in the base area.

From a design point of view, a space elevator consists of two parallel pipes or shafts of rectangular cross-section, the thickness of the walls of which varies according to a certain law. Along one of them the cabins move up, and along the other - down. Of course, nothing prevents you from building several of these pairs. The pipe may not be continuous, but consist of many parallel cables, the position of which is fixed by a series of transverse rectangular frames. This makes it easier to install and repair the elevator.

Elevator cabins are simply platforms driven by individual electric motors. Loads or residential modules are attached to them - after all, a trip in an elevator can last a week, or even more.

To save energy, you can create a system that resembles a cable car. It consists of a series of pulleys through which closed cables with cabins suspended on them are thrown. The pulley axes, where the electric motors are mounted, are mounted on the elevator carrier. Here the weight of the rising and falling cabins is mutually balanced, and, therefore, energy is spent only on overcoming friction.

For the connecting “threads”, from which the elevator itself is formed, it is necessary to use a material whose breaking stress to density ratio is 50 times greater than that of steel. These can be various “composites”, foam steels, beryllium alloys or crystal whiskers...

However, Georgy Polyakov does not stop at clarifying the characteristics of the space elevator. He points out the fact that by the end of the 20th century, geosynchronous orbit will be densely “strewn” with spacecraft of various types and purposes. And since all of them will be practically motionless relative to our planet, it seems very tempting to connect them with the Earth and with each other using space elevators and a ring transport highway.

Based on this consideration, Polyakov puts forward the idea of ​​a cosmic “necklace” of the Earth. The necklace will serve as a kind of cable car (or rail) between orbital stations, and will also provide them with stable balance in geosynchronous orbit.

Since the length of the “necklace” is very large (260,000 kilometers), a lot of stations can be placed on it. If, say, the settlements are 100 kilometers apart, then their number will be 2600. With a population of 10 thousand at each station, 26 million people will live on the ring. If the size and number of such “astrocities” are increased, this figure will increase sharply.

Space elevator design

Base

ABOUT The base of a space elevator is the place on the surface of the planet where the cable is attached and the lifting of the load begins. It can be mobile, placed on an ocean-going vessel. The advantage of a movable base is the ability to perform maneuvers to evade hurricanes and storms. The advantages of a stationary base are cheaper and more accessible energy sources, and the ability to reduce the length of the cable. The difference of a few kilometers of tether is relatively small, but can help reduce the required thickness of its middle part and the length of the part extending beyond geostationary orbit. In addition to the base, a platform on stratospheric balloons can be placed to reduce the weight of the lower part of the cable with the ability to change the height to avoid the most turbulent air flows, as well as dampen excessive vibrations along the entire length of the cable.

Cable

The cable must be made of a material with an extremely high tensile strength to specific gravity ratio. The space elevator will be economically justified if it is possible to produce on an industrial scale at a reasonable price a cable with a density comparable to graphite and a strength of about 65-120 gigapascals. For comparison, the strength of most types of steel is about 1 GPa, and even the strongest types are no more than 5 GPa, and steel is heavy. The much lighter Kevlar has a strength in the range of 2.6-4.1 GPa, and quartz fiber has a strength of up to 20 GPa and higher. Carbon nanotubes should, according to theory, have a stretchability much higher than that required for a space elevator. However, the technology for producing them in industrial quantities and weaving them into cables is just beginning to be developed. Theoretically, their strength should be more than 120 GPa, but in practice the highest tensile strength of a single-walled nanotube was 52 GPa, and on average they broke in the range of 30-50 GPa. The strongest thread, woven from nanotubes, will be weaker than its components.

In an experiment by scientists from the University of Southern California (USA), single-walled carbon nanotubes demonstrated a specific strength 117 times higher than steel and 30 times higher than Kevlar. It was possible to reach a value of 98.9 GPa, the maximum value of the nanotube length was 195 μm. According to some scientists, even carbon nanotubes will never be strong enough to make a space elevator cable.

Experiments by scientists from the University of Technology Sydney made it possible to create graphene paper. Sample tests are encouraging: the density of the material is five to six times lower than that of steel, while the tensile strength is ten times higher than that of carbon steel. At the same time, graphene is a good conductor of electric current, which allows it to be used to transmit power to a lift as a contact bus.

In June 2013, engineers from Columbia University in the USA reported a new breakthrough: thanks to new technology When obtaining graphene, it is possible to obtain sheets with a diagonal size of several tens of centimeters and a strength only 10% less than the theoretical one.

Thickening the cable

The space elevator must at least support its own weight, which is considerable due to the length of the cable. Thickening on the one hand increases the strength of the cable, on the other, it adds its weight, and, consequently, the required strength. The load on it will vary in different places: in some cases, a section of the tether must support the weight of the segments below, in others it must withstand the centrifugal force that holds the upper parts of the tether in orbit. To satisfy this condition and to achieve optimality of the cable at each point, its thickness will be variable.

It can be shown that taking into account the Earth's gravity and centrifugal force, BUT, not taking into account the smaller influence of the Moon and the Sun, the cross-section of the cable depending on the height will be described by the following formula:

Where is the cross-sectional area of ​​the cable as a function of the distance r from the center of the Earth.

The formula uses the following constants:

- cross-sectional area of ​​the cable at the Earth's surface level.

- density of the cable material.

- tensile strength of the cable material.

- The circular frequency of the Earth's rotation around its axis is 7.292·10−5 radians per second.

- the distance between the center of the Earth and the base of the cable. It is approximately equal to the radius of the Earth, 6,378 km.

- free fall acceleration at the base of the cable, 9.780 m/s².

This equation describes a tether whose thickness first increases exponentially, then its growth slows down at an altitude of several Earth radii, and then it becomes constant, eventually reaching geostationary orbit. After this, the thickness begins to decrease again.

Thus, the ratio of the cross-sectional areas of the cable at the base and at the GSO (r = 42,164 km) is:

P
putting here the density and strength of steel, and the diameter of the cable at the ground level of 1 cm, we get a diameter at the GSO level of several hundred kilometers, which means that steel and other materials familiar to us are unsuitable for building an elevator.

It follows that there are four ways to achieve a more reasonable cable thickness at the GSO level:

Use less dense material. Since the density of most solids lies in the relatively small range from 1000 to 5000 kg/m³, it is unlikely that anything will be achieved here.

Use more durable material. Research is mainly going in this direction. Carbon nanotubes are tens of times stronger than the best steel, and they will significantly reduce the thickness of the cable at the GSO level. The same calculation, made on the assumption that the cable density is equal to the carbon fiber density ρ = 1.9 g/cm3 (1900 kg/m3), with an ultimate strength σ = 90 GPA (90 109 Pa) and a cable diameter at the base of 1 cm ( 0.01 m), allows you to obtain a cable diameter at GSO of only 9 cm.

Raise the base of the cable higher. Due to the presence of the exponential in the equation, even a slight raising of the base will greatly reduce the thickness of the cable. Towers with a height of up to 100 km are proposed, which, in addition to saving on the cable, will avoid the influence of atmospheric processes.

Make the base of the cable as thin as possible. It still needs to be thick enough to support a loaded lift, so the minimum thickness at the base also depends on the strength of the material. A cable made of carbon nanotubes only needs to be one millimeter thick at the base.

Another way is to make the base of the elevator movable. Moving even at a speed of 100 m/s will already give a gain in circular speed by 20% and reduce the cable length by 20-25%, which will make it lighter by 50 percent or more. If you “anchor” the cable on a supersonic plane or train, then the gain in cable mass will no longer be measured in percentages, but in dozens of times (but losses due to air resistance are not taken into account). There is also an idea to use conditional lines of force of the Earth’s magnetic field instead of a cable made of nanotubes.

Counterweight

A counterweight can be created in two ways - by tying a heavy object (for example, an asteroid, a space settlement or a space dock) beyond geostationary orbit, or by extending the tether itself a significant distance beyond geostationary orbit. The second option is interesting because it is easier to launch loads to other planets from the end of the elongated cable, since it has a significant speed relative to the Earth.

Angular Momentum, Velocity and Tilt

The horizontal speed of each section of the cable increases with height in proportion to the distance to the center of the Earth, reaching the first cosmic speed in geostationary orbit. Therefore, when lifting a load, he needs to gain additional angular momentum (horizontal speed). Angular momentum is acquired due to the rotation of the Earth. At first, the lift moves slightly slower than the cable (Coriolis effect), thereby “slowing down” the cable and slightly deflecting it to the west. At an ascent speed of 200 km/h, the cable will tilt by 1 degree. The horizontal component of tension in a non-vertical cable pulls the load to the side, accelerating it in an easterly direction - due to this, the elevator acquires additional speed. According to Newton's third law, the cable slows down the Earth by a small amount, and the counterweight by a large amount, as a result of the slowdown in the rotation of the counterweight, the cable will begin to wrap around the ground. At the same time, the influence of centrifugal force forces the cable to return to an energetically favorable vertical position, so that it will be in a state of stable equilibrium. If the elevator's center of gravity is always above the geostationary orbit, regardless of the speed of the elevators, it will not fall. By the time the payload reaches geostationary orbit (GEO), its angular momentum is sufficient to launch the payload into orbit. If the load is not released from the cable, then, stopping vertically at the GSO level, it will be in a state of unstable equilibrium, and with an infinitesimal downward push, it will leave the GSO and begin to fall to the Earth with vertical acceleration, while slowing down in the horizontal direction. The loss of kinetic energy from the horizontal component during descent will be transferred through the cable to the angular momentum of the Earth's rotation, accelerating its rotation. When pushed upward, the load will also leave the GSO, but in the opposite direction, that is, it will begin to rise along the cable with acceleration from the Earth, reaching the final speed at the end of the cable. Since the final speed depends on the length of the cable, its value can thus be set arbitrarily. It should be noted that the acceleration and increase in the kinetic energy of the load during lifting, that is, its unwinding in a spiral, will occur due to the rotation of the Earth, which will slow down. This process is completely reversible, that is, if you put a load on the end of the cable and begin to lower it, compressing it in a spiral, the angular momentum of the Earth’s rotation will increase accordingly. When lowering the load, the reverse process will occur, tilting the cable to the east.

Launch into space

At the end of the cable at an altitude of 144,000 km, the tangential component of the speed will be 10.93 km/s, which is more than enough to leave the Earth's gravitational field and launch ships to Saturn. If the object was allowed to slide freely along the top of the tether, it would have enough speed to escape the solar system. This will happen due to the transition of the total angular momentum of the cable (and the Earth) into the speed of the launched object. To achieve even greater speeds, you can lengthen the cable or accelerate the load using electromagnetism.

Description of modern projects

More detailed proposals emerged in the mid to late 20th century. It was hoped that the space elevator would revolutionize access to near-Earth space, to the Moon, Mars and even beyond. This building could once and for all to solve the problem associated with sending a person into space. The elevator would greatly help many space agencies in transporting astronauts into orbit of our planet. Its creation could mean the end of space-polluting rockets. However, the initial investment and the level of technology required made it clear that such a project was impractical and relegated it to the realm of science fiction.

Is it possible to solve the problem of such construction at the moment? Proponents of space elevators believe that there are currently enough capabilities to solve this technical problem. They believe that space rockets are outdated and cause irreparable harm to nature and are too expensive for modern society.

The stumbling block lies in how to build such a system. “To begin with, it must be created from a material that does not yet exist, but is strong and flexible with the necessary mass and density characteristics to support transport and withstand incredible impact external forces, says Fong. “I think all this will require a series of the most ambitious orbital missions and space walks in low and high Earth orbit in the history of our species.”

There are also safety concerns, he adds. “Even if we could solve the significant technical difficulties associated with building such a thing, a scary picture emerges of a giant cheese with holes made by all this space debris and debris on top.”

Scientists around the world are developing the idea of ​​a space elevator. The Japanese announced in early 2012 that they were planning to build a space elevator. The Americans reported the same thing at the end of 2012. In 2013, the media remembered the Russian roots of the “space elevator.” So, when will these ideas become reality?

Concept of the Japanese Obayashi Corporation

The corporation proposes the following construction method: one end of a very high-strength cable is held by a massive platform in the ocean, and the other is secured to an orbital station. A specially designed cabin moves along the rope, which can deliver cargo, astronauts or, say, space tourists.

Obayashi is considering carbon nanotubes, which are tens of times stronger than steel, as a material for the cable. But the problem is that currently the length of such nanotubes is limited to about 3 cm, while a space elevator would require a cable with a total length of 96,000 km. It is expected that it will be possible to overcome the existing difficulties approximately in the 2030s, after which the practical implementation of the space elevator concept will begin.

Obayashi is already considering the possibility of creating special tourist cabins designed to carry up to 30 passengers. By the way, the journey to orbit along a cable made of carbon nanotubes will take seven days, so the necessary life support systems, food and water supplies will have to be provided.

Obayashi expects to launch the space elevator only by 2050.

Space elevator from LiftPort Group

Not only the Earth will become an object where such an elevator will be built. According to a group of experts from the LiftPort Group company, the Moon may well act as such an object.

The basis of the lunar space elevator is a flat ribbon cable made of high-strength material. Transport gondolas will travel along this cable to the surface of the Moon and back, delivering people, various materials, mechanisms and robots.

The “space” end of the cable will be held by the PicoGravity Laboratory (PGL) space station located at the L1 Lagrange point of the Moon-Earth system, the point where the gravity of the Moon and Earth cancel each other out. On the Moon, the end of the cable will be connected to the Anchor Station, located in the Sinus Medi region (approximately in the middle of the “face” of the Moon looking at the Earth) and part of the Lunar Space Elevator Infrastructure.

The tension of the space elevator cable will be carried out by a counterweight, which will be held by a thinner cable 250 thousand kilometers long, and which will already be at the mercy of earth's gravity. The PicoGravity Laboratory space station will have a modular structure, similar to the structure of the existing International Space Station, which will make it possible to easily expand it and add docking nodes that allow different types of spacecraft to dock with the station.

The main goal of this project is not the construction of the space elevator itself. This elevator will only be a means of delivering automatic vehicles to the Moon, which will autonomously mine various minerals, including rare earth metals and helium-3, which is a promising fuel for future thermonuclear fusion reactors and, possibly, fuel for future spaceships .

“Unfortunately, this project is still practically impossible due to people’s lack of many key technologies. But research into most of these technologies has been going on for some time, and there will definitely come a time when building a space elevator will move from the category of science fiction to the realm of practically feasible things.”

LiftPort Group specialists promise to make a working, detailed design of the structure by the end of 2019.

"Planetary vehicle»

Let's consider a project called the General Planetary Vehicle (GVT). It was put forward and substantiated by engineer Anatoly Yunitsky from Gomel.

In 1982, an article was published in the journal “Technology for Youth” in which the author claims that humanity will soon have a need for a fundamentally new vehicle capable of providing transportation on the Earth-Space-Earth route.

According to A. Yunitsky, the GPV is a closed wheel with a transverse diameter of about 10 meters, which rests on a special overpass installed along the equator. The height of the overpass, depending on the terrain, ranges from several tens to several hundred meters. The overpass is placed on floating supports in the ocean.

In a sealed channel located along the axis of the GPV body, there is an endless belt, which has a magnetic suspension and is a kind of engine rotor. A current is induced into it, which will interact with the magnetic field that generated it, and the tape, which does not experience any resistance (it is placed in a vacuum), will begin to move. More precisely, in rotation around the Earth. Upon reaching the first escape velocity, the tape will become weightless. With further acceleration, its centrifugal force through the magnetic suspension will begin to exert an ever-increasing vertical lifting force on the GPV body until it balances every linear meter of it (the vehicle will seem to become weightless - why not an anti-gravity ship?).

Cargo and passengers are placed in a vehicle held on the overpass with an upper belt previously spun to a speed of 16 km/s, having a mass of 9 tons per meter, and exactly the same, but lying motionless lower belt. This is done mainly inside, and partly outside, the GPV body, but so that the load as a whole is evenly distributed. After being freed from the grips holding the GPV on the overpass, its diameter, under the influence of the lifting force, will begin to slowly grow, and each linear meter of it will rise above the Earth. Since the shape of the circle corresponds to the minimum energy, the vehicle, which previously copied the profile of the overpass, will take the shape of an ideal ring after lifting.

The ascent speed of the vehicle on any section of the route can be set within wide limits: from pedestrian speed to airplane speed. The vehicle passes through the atmospheric section at minimum speeds.

According to Anatoly Yunitsky, the total weight of the GPV will be 1.6 million tons, carrying capacity - 200 million tons, passenger capacity - 200 million people. The estimated number of GPV spacewalks over a fifty-year service life is 10 thousand flights.

Conclusion

There are many space elevator projects, and all of them differ little from what Artsupanov proposed, but now scientists assume that nanotube materials will become available.

The space elevator will revolutionize the space industry by delivering people and cargo into orbit at a significantly lower cost than traditional launch vehicles.

Let's hope that in the second half of the 21st century, space elevators will begin to function beyond the Earth: on the Moon, Mars and other places Solar System. With the development of technology, construction costs will gradually decrease.

Despite the fact that this time seems distant and unattainable, it depends on us what the future will be and how quickly it will come.

What boy doesn't dream of becoming an astronaut? However, only a few people around the world can achieve this dream, and only very rich people can go on a private space flight. But in 2050, almost anyone will be able to get into orbit. After all Japan promises to launch the world's first by this time elevator to space.

Among the many efforts to explore outer space, one can separately highlight the initiative of the Japanese construction corporation Obayashi to create an orbital elevator. This vehicle, according to the authors, should appear by 2050. It promises to be the cheapest way to deliver people and cargo into space.

The elevator will move at a speed of 200 kilometers per hour along an ultra-strong and ultra-light cable leading from the earth's surface to a distant orbital station, where not only a scientific laboratory will be located, but also a hotel for space tourists, of whom, with the advent of this type of transport, there will be hundreds or even thousands of times more than exists in our time.

What makes Obayashi's bold promise possible is the development of new materials that can create fibers that are a hundred times stronger than steel. And these technologies are developing with every new year, with every new month.

There are also annual international technical competitions in which participants work on ideas for implementing a space elevator. They are developing new materials and innovative technologies for delivering cargo into orbit. At the same time, every year the ideas become more clear and promising.

The combination of the factors described above is precisely what allows Obayashi Corporation to make stunning claims about the possibility of launching an orbital elevator by 2050.

According to theoretical calculations, they seem to be a suitable material. If we assume their suitability for the manufacture of a cable, then the creation of a space elevator is a solvable engineering problem, although it requires the use of advanced developments and. NASA is already funding the corresponding developments of the American Institute scientific research, including the development of a lift capable of moving independently along a cable. Presumably, this method in the future could be orders of magnitude cheaper than using launch vehicles.

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Subtitles

Design

For comparison, the strength of most types of steel is about 1 GPa, and even the strongest types are no more than 5 GPa, and steel is heavy. The much lighter Kevlar has a strength in the range of 2.6-4.1 GPa, and quartz fiber has a strength of up to 20 GPa and higher. The theoretical strength of diamond fibers may be slightly higher.

The technology for weaving such fibers is still in its infancy.

According to some scientists, even carbon nanotubes will never be strong enough to make a space elevator cable.

Experiments by scientists from the University of Technology Sydney made it possible to create graphene paper. Sample tests are encouraging: the density of the material is five to six times lower than that of steel, while the tensile strength is ten times higher than that of carbon steel. At the same time, graphene is a good conductor of electric current, which allows it to be used to transmit power to a lift as a contact bus.

In June 2013, engineers from Columbia University in the USA reported a new breakthrough: thanks to a new technology for producing graphene, it is possible to obtain sheets with a diagonal size of several tens of centimeters and a strength only 10% less than theoretical.

Thickening the cable

The space elevator must support at least its own weight, which is considerable due to the length of the cable. Thickening on the one hand increases the strength of the cable, on the other, it adds its weight, and therefore the required strength. The load on it will vary in different places: in some cases, a section of the cable must withstand the weight of the segments located below, in others it must withstand the centrifugal force that holds the upper parts of the cable in orbit. To satisfy this condition and to achieve optimality of the cable at each point, its thickness will be variable.

It can be shown that taking into account the Earth's gravity and centrifugal force (but not taking into account the smaller influence of the Moon and the Sun), the cross-section of the cable depending on the height will be described by the following formula:

A (r) = A 0 exp ⁡ [ ρ s [ 1 2 ω 2 (r 0 2 − r 2) + g 0 r 0 (1 − r 0 r) ] ] (\displaystyle A(r)=A_(0 )\ \exp \left[(\frac (\rho )(s))\left[(\begin(matrix)(\frac (1)(2))\end(matrix))\omega ^(2)( r_(0)^(2)-r^(2))+g_(0)r_(0)(1-(\frac (r_(0))(r)))\right]\right])

Here A (r) (\displaystyle A(r))- cross-sectional area of ​​the cable as a function of distance r (\displaystyle r) from center Earth.

The formula uses the following constants:

This equation describes a tether whose thickness first increases exponentially, then its growth slows down at an altitude of several Earth radii, and then it becomes constant, eventually reaching geostationary orbit. After this, the thickness begins to decrease again.

Thus, the ratio of the cross-sectional areas of the cable at the base and at the GSO ( r= 42,164 km) is: A (r G E O) A 0 = exp ⁡ [ ρ s × 4 , 832 × 10 7 m 2 s 2 ] (\displaystyle (\frac (A(r_(\mathrm (GEO) )))(A_(0)) )=\exp \left[(\frac (\rho )(s))\times 4.832\times 10^(7)\,\mathrm (\frac (m^(2))(s^(2))) \right])

Substituting here the density and strength for various materials and different cable diameters at the ground level, we get a table of cable diameters at the GSO level. It should be noted that the calculation was carried out under the condition that the elevator would stand “by itself”, without load - since the cable material is already experiencing tension from its own weight (and these loads are close to the maximum permissible for this material).

The diameter of the cable at GSO, depending on its diameter at ground level,
for various materials (calculated using the latest formula), m

Material	Density ρ (\displaystyle \rho ), kg÷m 3	Tensile strength s (\displaystyle s), Pa	Cable diameter at ground level
			1 mm	1 cm	10 cm	1m
Steel St3 hot rolled	7760	0.37 10 9	1.31 10 437	1.31 10 438	1.31 10 439	1.31 10 440
High alloy steel 30KhGSA	7780	1.4 10 9	4.14 10 113	4.14 10 114	4.14 10 115	4.14 10 116
Web	1000	2.5 10 9	0.248 10 6	2.48 10 6	24.8 10 6	248 10 6
Modern carbon fiber	1900	4 10 9	9.269 10 6	92.69 10 6	926.9 10 6	9269 10 6
Carbon nanotubes	1900	90 10 9	2.773·10 -3	2.773·10 -2	2.773·10 -1	2.773

Thus, it is unrealistic to build an elevator from modern structural steels. The only way out is to look for materials with lower density and/or very high strength.

For example, the table includes cobwebs (spider silk). There are various exotic projects for the production of webs on “spider farms”. Recently there have been reports that, with the help of genetic engineering, it was possible to introduce a spider gene encoding a spider web protein into a goat’s body. Now the milk of a genetically modified goat contains spider protein. Whether it is possible to obtain from this protein a material resembling a spider's web in its properties is still unknown. But, according to the press, such developments are underway

Another promising direction is carbon fiber and carbon nanotubes. Carbon fiber is successfully used in industry today. Nanotubes are about 20 times stronger, but the technology for producing this material has not yet left the laboratory. The table was built on the assumption that the density of a cable made of nanotubes is the same as that of carbon fiber.

Listed below are several more exotic ways to build a space elevator:

Counterweight

A counterweight can be created in two ways - by tying a heavy object (for example, an asteroid, a space settlement or a space dock) beyond geostationary orbit, or by extending the tether itself a significant distance beyond geostationary orbit. The second option is interesting because it is easier to launch loads to other planets from the end of the elongated cable, since it has a significant speed relative to the Earth.

Angular Momentum, Velocity and Tilt

The horizontal speed of each section of the cable increases with height in proportion to the distance to the center of the Earth, reaching the first cosmic speed in geostationary orbit. Therefore, when lifting a load, it needs to gain additional angular momentum (horizontal speed).

Angular momentum is acquired due to the rotation of the Earth. At first, the lift moves slightly slower than the cable (Coriolis effect), thereby “slowing down” the cable and slightly deflecting it to the west. At an ascent speed of 200 km/h, the cable will tilt by 1 degree. The horizontal component of tension in a non-vertical cable pulls the load to the side, accelerating it in an easterly direction (see diagram) - due to this, the elevator acquires additional speed. According to Newton's third law, the cable slows down the Earth by a small amount, and the counterweight by a significantly larger amount; as a result of the slowdown in the rotation of the counterweight, the cable will begin to wrap around the ground.

At the same time, the influence of centrifugal force forces the cable to return to an energetically favorable vertical position [ ], so that it will be in a state of stable equilibrium. If the elevator's center of gravity is always above the geostationary orbit, regardless of the speed of the elevators, it will not fall.

By the time the payload reaches geostationary orbit (GEO), its angular momentum is sufficient to launch the payload into orbit. If the load is not released from the cable, then, stopping vertically at the GSO level, it will be in a state of unstable equilibrium, and with an infinitesimal downward push, it will leave the GSO and begin to fall to the Earth with vertical acceleration, while slowing down in the horizontal direction. The loss of kinetic energy from the horizontal component during descent will be transferred through the cable to the angular momentum of the Earth's rotation, accelerating its rotation. When pushed upward, the load will also leave the GSO, but in the opposite direction, that is, it will begin to rise along the cable with acceleration from the Earth, reaching the final speed at the end of the cable. Since the final speed depends on the length of the cable, its value can thus be set arbitrarily. It should be noted that the acceleration and increase in the kinetic energy of the load during lifting, that is, its unwinding in a spiral, will occur due to the rotation of the Earth, which will slow down. This process is completely reversible, that is, if you put a load on the end of the cable and begin to lower it, compressing it in a spiral, the angular momentum of the Earth’s rotation will increase accordingly.

When lowering the load, the reverse process will occur, tilting the cable to the east.

Launch into space

At the end of the cable at an altitude of 144,000 km, the tangential component of the speed will be 10.93 km/s, which is more than enough to leave the Earth's gravitational field and launch ships to Saturn. If the object was allowed to slide freely along the top of the tether, it would have enough speed to escape the solar system. This will happen due to the transition of the total angular momentum of the cable (and the Earth) into the speed of the launched object.

To achieve even greater speeds, you can lengthen the cable or accelerate the load using electromagnetism.

On other planets

A space elevator can be built on other planets. Moreover, the lower the gravity on the planet and the faster it rotates, the easier it is to carry out construction.

It is also possible to extend a space elevator between two celestial bodies that orbit each other and constantly face each other (for example, between Pluto and Charon or between the components of the double asteroid (90) Antiope. However, since their orbits are not an exact circle, it will be necessary a device for constantly changing the length of such an elevator. In this case, the elevator can be used not only for carrying cargo into space, but also for “interplanetary travel.”

Construction

Construction is carried out from a geostationary station. One end descends to the surface of the Earth, stretched by the force of gravity. The other, for balancing, is in the opposite direction, being pulled by centrifugal force. This means that all materials for construction must be delivered to geostationary orbit in the traditional way. That is, the cost of delivering the entire space elevator to geostationary orbit is the minimum price of the project.

Savings from using a space elevator

Presumably, the space elevator will greatly reduce the cost of sending cargo into space. Space elevators are expensive to build, but their operating costs are low, so they are best used over long periods of time for very large volumes of cargo. Currently, the cargo launch market is not large enough to justify building an elevator, but the dramatic reduction in price should lead to an expansion of the market.

There is still no answer to the question whether the space elevator will return the money invested in it or whether it would be better to invest it in the further development of rocket technology.

However, the elevator can be a hybrid project and, in addition to the function of delivering cargo into orbit, remain a base for other research and commercial programs not related to transport.

Achievements

Since 2005, the annual Space Elevator Games competition has been held in the United States, organized by the Spaceward Foundation with the support of NASA. There are two categories in these competitions: “best cable” and “best robot (lift)”.

In the lift competition, the robot must cover a set distance, climbing a vertical cable at a speed not lower than that established by the rules (in the 2007 competition, the standards were as follows: cable length - 100 m, minimum speed - 2 m/s, the speed of which must be achieved is 10 m/s) . The best result of 2007 was covering a distance of 100 m with an average speed of 1.8 m/s.

The total prize fund for the Space Elevator Games competition in 2009 was $4 million.

In the rope strength competition, participants must provide a two-meter ring made of heavy-duty material weighing no more than 2 grams, which a special installation tests for rupture. To win the competition, the strength of the cable must be at least 50% greater in this indicator than the sample already available to NASA. So far, the best result belongs to the cable that withstood a load of up to 0.72 tons.

The competition does not include Liftport Group, which gained notoriety for its claims to launch a space elevator in 2018 (later pushed back to 2031). Liftport conducts its own experiments, for example, in 2006, a robotic lift climbed a strong rope stretched using balloons. Out of one and a half kilometers, the lift managed to cover only 460 meters. In August-September 2012, the company launched a project to raise funds for new experiments with the lift on the Kickstarter website. Depending on the amount collected, it is planned to lift the robot 2 or more kilometers.

The LiftPort Group also announced its readiness to build an experimental space elevator on the Moon, based on existing technologies. Company President Michael Lane says it could take eight years to build such an elevator. Attention to the project forced the company to set a new goal - preparing the project and raising additional funds to begin a feasibility study of the so-called “lunar elevator.” According to Lane, the construction of such an elevator will take one year and cost $3 million. NASA specialists have already drawn attention to the LiftGroup project. Michael Lane collaborated with the US Space Agency on a space elevator project.

Similar projects

The space elevator is not the only project that uses tethers to launch satellites into orbit. One such project is Orbital Skyhook (orbital hook). Skyhook uses a tether that is not very long compared to a space elevator, which is in low Earth orbit and rotates quickly around its middle part. Due to this, one end of the cable moves relative to the Earth at a relatively low speed, and loads from hypersonic aircraft can be suspended from it. At the same time, the Skyhook design works like a giant flywheel - an accumulator of torque and kinetic energy. The advantage of the Skyhook project is its feasibility using existing technologies. The downside is that Skyhook uses energy from its motion to launch satellites, and this energy will need to be replenished somehow.

Project Stratosphere Network of Skyscrapers. The project is a network of orbital elevators, united in hexagons, covering the entire planet. When moving to the next stages of construction, the supports are removed, and the frame of the elevator network is used to build a stratospheric settlement on it. The project provides for several habitat areas.

Space elevator in various works

• Robert Heinlein's book Friday uses a space elevator called a "beanstalk"
• In the 1972 USSR film Petka in Space, the main character invents a space elevator.
• One of Arthur Clarke's famous works, The Fountains of Paradise, is based on the idea of ​​a space elevator. In addition, the space elevator appears in the final part of his famous tetralogy, A Space Odyssey (3001: The Last Odyssey).
• In Star Trek: Voyager episode 3.19, "Rise," a space elevator helps the crew escape a planet with a dangerous atmosphere.
• Civilization IV has a space elevator. There he is one of the later “Great Miracles”.
• Timothy Zahn's science fiction novel “Silkworm” (“Spinneret”, 1985) mentions a planet capable of producing superfiber. One of the races, interested in the planet, wanted to get this fiber specifically for the construction of a space elevator.
• In Frank Schötzing's science fiction novel Limit, a space elevator acts as a central point of political intrigue in the near future.
• In Sergei Lukyanenko’s dilogy “Stars - Cold Toys,” one of the extraterrestrial civilizations, in the process of interstellar trade, delivered to Earth super-strong threads that could be used to build a space elevator. But extraterrestrial civilizations insisted exclusively on using them for their intended purpose - to help during childbirth.
• In the science fiction novel by J. Scalzi “Doomed to Victory” (eng. Scalzi, John. Old Man’s War), space elevator systems are actively used on Earth, numerous terrestrial colonies and some planets of other highly developed intelligent races for communication with the berths of interstellar ships.
• In the science fiction novel “Tomorrow Will Be Eternity” by Alexander Gromov, the plot is built around the fact of the existence of a space elevator. There are two devices - a source and a receiver, which, using an “energy beam”, are capable of raising the elevator “cabin” into orbit.
• In Alastair Reynolds' fantasy novel The Abyss City, detailed description the structure and functioning of the space elevator, the process of its destruction (as a result of a terrorist attack) is described.
• Terry Pratchett's science fiction novel Strata features the Line, an extremely long artificial molecule used as a space elevator.
• In Graham McNeill's science fiction novel Mechanicum, space elevators are present on Mars and are called Tsiolkovsky Towers
• Mentioned in the song by the group Zvuki Mu “Elevator to Heaven.”
• At the very beginning of the Sonic Colors game, Sonic and Tails can be seen taking the space elevator to get to Dr. Eggman's Park.
• In Alexander Zorich’s book “Somnambulist 2” from the Ethnogenesis series, the main character Matvey Gumilyov (after planting a surrogate personality - Maxim Verkhovtsev, the personal pilot of comrade Alpha, the head of “Star Fighters”) travels in an orbital elevator.
• In the story “The Serpent” by science fiction writer Alexander Gromov, the heroes use a space elevator “on the way” from the Moon to the earth.
• In the series of science fiction novels