Anyone who thinks that nanotechnology can only create something submicroscopic, invisible to the human eye, will probably be surprised by the project being developed in Lately specialists from NASA and attracted so much attention from scientists and the general public. It's about about the so-called space elevator project.
A space elevator is a cable several tens of thousands of kilometers long that connects an orbiting space station to a platform located in the middle of the Pacific Ocean.
The idea of a space elevator is more than a century old. The first to speak about it in 1895 was the great Russian scientist Konstantin Tsiolkovsky, the founder of modern cosmonautics. He pointed out that the principle underlying modern rocket science does not allow modern launch vehicles to be effective means for delivering cargo into space. There are several reasons for this:
Firstly, the efficiency of modern rockets is very low due to the fact that the lion's share of the power of the first stage engines goes to work on overcoming the force of gravity.
Secondly, it is known that a significant increase in fuel mass several times gives only a small increase in speedrockets. That is why, for example, the American Saturn-Apollo rocket system, with a launch mass of 2900 tons, launched only 129 tons into orbit. Hence the astronomical cost of space launches using rockets (the cost of launching a kilogram of cargo into low orbit averages about $10,000.)
And, despite repeated attempts to reduce the cost of launching rockets, it appears that the cost of transporting goods and people into orbit is radically reduced to the cost of standard air transportation based on modern rocket technologies
fundamentally impossible.
To send cargo into space more cheaply, researchers at Los Alamos National Laboratory proposed creating a space elevator. According to preliminary estimates, the cost of launching cargo using an elevator could drop from tens of thousands of dollars to $10 per kilogram. Scientists believe
that the space elevator could literally turn the world upside down, giving humanity completely new opportunities.
Essentially, the elevator will be a cable connecting the orbital station to a platform on the surface of the Earth. Crawler-mounted cabins will move up and down along the cable, carrying satellites and probes that need to be launched into orbit. With the help of this elevator, at the very top it will be possible to build a launch pad in space for spacecraft heading to the Moon, Mars, Venus and asteroids. The problem of supplying energy to the elevator “cabins” themselves has been solved in an original way: the cable will be covered with solar panels or the cabins will be equipped with small photovoltaic panels, which will be illuminated by powerful lasers from the Earth.
Scientists propose placing the ground base of the space elevator in the ocean, in the equatorial waters of the Pacific Ocean, hundreds of kilometers from commercial flight routes. It is known that hurricanes never cross the equator and there is almost no lightning here, which will provide the elevator with additional protection.
The space elevator is described in the works of Tsiolkovsky, as well as the science fiction writer Arthur C. Clarke, and the project for the construction of such an elevator was developed by Leningrad engineer Yuri Artsutanov in 1960. For many years, an active promoter of the idea of a space elevator was the Astrakhan
scientist G. Polyakov.
But until now no one has been able to offer a material so light and strong that it could be used to make a space cable. Until recently, the most durable material was steel. But it is not possible to make a cable several thousand kilometers long from steel, since even simplified calculations indicate that steel rope of the required strength would have collapsed under its own weight already at an altitude of 50 km.
However, with the development of nanotechnology, a real opportunity has arisen to produce a cable with the necessary characteristics based on fibers made of ultra-strong and ultra-light carbon nanotubes. So far, no one has managed to make even a meter-long cable from nanotubes, but, according to the project developers, nanotube production technologies are being improved every day, so such a cable could well be made in just a few years.
The main element of the lift is a cable, one end of which is attached to the surface of the Earth, and the other is lost in space at an altitude of about 100 thousand km. This cable will not just “dangle” in outer space, but will be stretched like a string, thanks to the influence of two multidirectional forces: the center
fleeing and centripetal.
To understand their nature, imagine that you tied an object to a rope and began to untwist it. As soon as it acquires a certain speed, the rope will tighten, because a centrifugal force acts on the object, and a centripetal force acts on the rope itself, which pulls it. Something similar will happen with a cable raised into space. Any object at its upper end, or even the free end itself, will rotate, like an artificial satellite of our planet, only “tied” with a special “rope” to the earth’s surface.
The balance of forces will occur when the center of mass of the giant rope is at an altitude of 36 thousand kilometers, that is, in the so-called geostationary orbit. It is there that artificial satellites hang motionless above the Earth, making a full revolution with it in 24 hours. In this case, it will not only be tensioned, but will also be able to constantly occupy a strictly defined position - vertical to the earth's horizon, exactly towards the center of our planet.
Figure 24. The space elevator as imagined by artist Pat Rawlings*
Reprinted from http://flightprojects.msfc.nasa.gov
To begin construction of a space elevator, it will be necessary to make a couple of space shuttle flights. They and a special platform with its own autonomous engine will deliver 20 tons of cable to geostationary orbit. Then it is supposed to lower one end of the cable to Earth and secure it somewhere in the equatorial zone of the Pacific Ocean on a platform similar to the current launch pad for launching rockets.
Then they plan to put special lifts along the cable, which will add more and more layers of nanotube coating to the cable, increasing its strength. This process should take a couple of years, and the first space elevator will be ready.
Curious coincidences: in 1979, science fiction writer Arthur C. Clarke, in his novel “The Fountains of Paradise,” put forward the idea of a “space elevator” and proposed replacing steel with a certain ultra-strong “pseudo-one-dimensional diamond crystal,” which became the main building material for this device. The most interesting thing is that Clark almost guessed. The current stage of interest in the project of building a space elevator is associated precisely with carbon crystals - nanotubes, which have remarkable properties, with which we have already become acquainted.
And what is absolutely surprising: the physicist, one of the participants in the development of the space elevator, is named Ron Morgan. Morgan was also the name of the character in Arthur C. Clarke's novel, the engineer who built the space elevator!
Despite the crisis and the war of sanctions in civilized economically developed countries There is great interest in astronautics. This is facilitated by advances in the development of rocket science and in the study of near-Earth space and planets using spacecraft. solar system and its periphery. More and more states are joining the space race. China and India loudly declare their ambitions to explore the Universe. Monopoly is becoming a thing of the past government agencies Russia, USA and Europe for flights beyond the earth's atmosphere. Businesses are showing increasing interest in transporting people and cargo into space orbit. Companies have appeared that are headed by enthusiasts who are in love with space. They are developing both new launch vehicles and new technologies that will make it possible to make a leap in the exploration of the Universe. Ideas that were considered unfeasible just yesterday are being seriously considered. And what was considered the fruit of the fevered imagination of science fiction writers is now one of the possible projects to be implemented in the near future.
One such project could be a space elevator.
How realistic is this? BBC journalist Nick Fleming tried to answer this question in his article “Elevator in Orbit: Science Fiction or a Matter of Time?”, which is brought to the attention of those interested in space.
Elevator to orbit: science fiction or a matter of time?
Thanks to space elevators capable of delivering people and cargo from the surface of the Earth into orbit, humanity could abandon the use of environmentally harmful rockets. But creating such a device is not easy, as a BBC Future correspondent found out.
When it comes to forecasts regarding the development of new technologies, many consider the authority of millionaire Elon Musk, one of the leaders in the non-governmental research sector, who came up with the idea of the Hyperloop - a high-speed pipeline passenger service project between Los Angeles and San Francisco (travel time takes only 35 minutes). But there are projects that even Musk considers practically impossible. For example, the space elevator project.
"It's too technical difficult task. It is unlikely that a space elevator can be created in reality,” Musk said at a conference at the Massachusetts Institute of Technology last fall. In his opinion, it is easier to build a bridge between Los Angeles and Tokyo than to build an elevator into orbit.
The idea of sending people and cargo into space inside capsules sliding upward along a giant cable held in place by the Earth's rotation is not new. Similar descriptions can be found in the works of science fiction writers such as Arthur C. Clarke. However, this concept has not yet been considered feasible in practice. Perhaps the confidence that we are capable of solving this extremely difficult technical problem, - is it really just self-deception?
Space elevator enthusiasts believe it is entirely possible to build one. In their opinion, rockets powered by toxic fuel are an outdated, dangerous for humans and nature, and excessively expensive form of space transport. The proposed alternative is essentially a railway line laid into orbit - a super-strong cable, one end of which is fixed to the Earth's surface, and the other to a counterweight located in geosynchronous orbit and therefore constantly hanging above one point on the Earth's surface. Electrical devices moving up and down along a cable would be used as elevator cabins. With space elevators, the cost of sending cargo into space could be reduced to $500 per kilogram - a figure that is now approximately $20,000 per kilogram, according to a recent report by the International Academy of Astronautics (IAA).
Space elevator enthusiasts point out the harmfulness of technologies for launching rockets into orbit
“This technology opens up phenomenal opportunities, it will provide humanity with access to the solar system,” says Peter Swan, president of the International Space Elevator Consortium ISEC and co-author of the IAA report. “I think that the first elevators will operate in automatic mode, and after 10 Within 15 years, we will have six to eight of these devices at our disposal that are safe enough to transport people."
Origins of the idea
The difficulty is that the height of such a structure must be up to 100,000 km - this is more than two earth equators. Accordingly, the structure must be strong enough to support its own weight. There is simply no material on Earth with the necessary strength characteristics.
But some scientists think that this problem can be solved already in the current century. Large Japanese construction company announced that it plans to build a space elevator by 2050. And American researchers recently created a new diamond-like material based on nanofilaments of compressed benzene, the calculated strength of which could make a space elevator a reality within many of us’s lifetimes.
The concept of a space elevator was first considered in 1895 by Konstantin Tsiolkovsky. A Russian scientist, inspired by the recently built Eiffel Tower in Paris, began researching the physics of building a giant tower that could carry spacecraft into orbit without the use of rockets. Later, in 1979, this topic was mentioned by science fiction writer Arthur C. Clarke in his novel The Fountains of Paradise - his main character is building a space elevator similar in design to the projects currently being discussed.
The question is how to bring the idea to life. “I love the audacity of the space elevator concept,” says Kevin Fong, founder of the Center for Altitude, Space and Extreme Medicine at University College London. “I can understand why people find it so attractive: the ability to travel to low Earth orbits inexpensively and safely opens up the entire inner solar system for us.”
Security issues
However, building a space elevator won't be easy. "To begin with, the cable must be made of super strong, but flexible material, having the necessary weight and density characteristics to support the weight of vehicles moving on it, and at the same time capable of withstanding constant lateral impacts. “Right now, that material simply doesn’t exist,” says Fong. - In addition, the construction of such an elevator will require the most intensive use of spaceships and the most large quantity exits to open space throughout the history of mankind." 
According to him, safety issues cannot be ignored: “Even if we manage to overcome the enormous technical difficulties associated with building an elevator, the resulting structure will be a giant stretched string, bringing together spacecraft from orbit and constantly bombarded by space debris."
Will tourists someday be able to use an elevator to travel into space?
Over the past 12 years, three detailed designs for a space elevator have been published around the world. The first is described by Brad Edwards and Eric Westling in the book “Space Elevators,” published in 2003. This elevator is designed to transport 20 tons of cargo using the energy of laser installations located on Earth. The estimated cost of transportation is $150 per kilogram, and the project cost is estimated at $6 billion.
In 2013, the IAA Academy developed this concept into own project, which provides increased protection of elevator cabins from atmospheric phenomena up to an altitude of 40 km, upon reaching which the movement of elevator cabins into orbit should occur due to solar energy. The cost of transportation is $500 per kilogram, and the cost of building the first two such elevators is $13 billion.
Early space elevator concepts included a variety of possible solutions problems of a space counterweight designed to keep the cable in a taut position - including the proposal to use an asteroid captured and delivered to the desired orbit for these purposes. The IAA report notes that such a solution may someday be implemented, but it is not possible in the near future.
Drogue"
To support a cable weighing 6,300 tons, the counterweight must weigh 1,900 tons. It can be partially formed from spaceships and other auxiliary devices, which will be used to build the elevator. It is also possible to use nearby spent satellites by towing them into a new orbit.
They also propose making the “anchor” that attaches the cable to the Earth, in the form of a floating platform the size of a large oil tanker or aircraft carrier, and placing it near the equator in order to increase its bearing capacity. An area 1000 km west of the Galapagos Islands, which is rarely subject to hurricanes, tornadoes and typhoons, is proposed as the optimal location for the “anchor”.
Space debris could be used as a counterweight at the top end of a space elevator cable
Obayashi Corp., one of Japan's five largest construction firms, last year announced plans to build a space elevator over robust construction, along which automatic booths on magnetic levitation would move. Similar technology is used on high-speed railways. A stronger cable is needed because the Japanese elevator is supposed to be used to transport people. The cost of the project is estimated at $100 billion, while the cost of transporting cargo into orbit can be $50-100 per kilogram.
While there will undoubtedly be many technical challenges in building such an elevator, the only structural element that cannot yet be built is the cable itself, says Swan: “The only technological problem that needs to be solved is finding the right material to make the cable. That's all.” we can build the rest now."
Diamond threads
On this moment The most suitable material for the cable is carbon nanotubes, created in laboratory conditions in 1991. These cylindrical structures have a tensile strength of 63 gigapascals, that is, they are about 13 times stronger than the strongest steel.
The maximum achievable length of such nanotubes is constantly increasing - in 2013, Chinese scientists managed to increase it to half a meter. The authors of the IAA report predict that the kilometer will be reached by 2022, and by 2030. It will be possible to create nanotubes of suitable length for use in a space elevator.
Meanwhile, last September, a new, ultra-strong material emerged: in a paper published in the materials science journal Nature Materials, a team of scientists led by chemistry professor John Bedding of Pennsylvania State University reported producing super-thin “diamond nanothreads” in the laboratory that could even stronger than carbon nanotubes.
Scientists have compressed liquid benzene under 200,000 times atmospheric pressure. Then the pressure was slowly reduced, and it turned out that the benzene atoms rearranged, creating a highly ordered structure of pyramidal tetrahedra.
As a result, super-thin threads were formed, very similar in structure to diamond. Although it is impossible to directly measure their strength due to their ultra-small size, theoretical calculations indicate that these threads may be stronger than the strongest synthetic materials available.
Risk reduction
"If we learn to create diamond nanothreads or carbon nanotubes of the required length and with necessary qualities, you can be pretty sure they'll be strong enough to be used in a space elevator," says Bedding.
However, even if you manage to find suitable material for a cable, assembling the structure will be very difficult. Most likely, difficulties will arise related to ensuring the safety of the project, the necessary financing and the proper management of competing interests. However, this does not stop Swan.
One way or another, humanity is striving for space and is ready to spend a lot of money on it
“Of course, we will encounter great difficulties, but problems had to be solved during the construction of the first transcontinental railway[in the US], and during the construction of the Panama and Suez Canals,” he says. - It will take a lot of time and money, but, as with any major project, you just need to solve problems as they arise, while gradually reducing possible risks."
Even Elon Musk is not ready to categorically dismiss the possibility of creating a space elevator. “I don’t think this idea is feasible today, but if someone can prove otherwise, that would be great,” he said at a conference at MIT last year.
In the 21st century, elevators are no longer just mechanisms that lift loads to a certain height. With increasing speed and load capacity, elevators are becoming more of vehicles.
As an example, we can offer the automobile giant from Japan, Mitsubishi. Its engineers developed an elevator capable of rising at a speed of 60 km/h. But as you will now see, this is not the limit.
Of course, such elevators are designed for the tallest buildings in the world - skyscrapers. And it doesn’t matter in which country the building is located, the main thing is that the elevator works. How else can you raise people to a height of 50 floors? And at 100? If the rate of ascent remains the same, then time will flow incredibly slowly. Therefore, the capacity of elevators is increasing every day.
The best in this matter are the Japanese. The Obayashi Corporation, after some reflection, announced that for it skyscrapers are far from the limit. The company's engineers are creating an elevator into space. Creation time: about 40 years. Most likely, by 2050 the grandiose construction will be completed.
It is planned to make the elevator cabin as spacious as possible in order to lift several dozen people. People will rise until they find themselves in space. Technologically this is possible. After all, engineers from Japan have developed a special cable made of carbon nanotubes. This material is almost two dozen times stronger and more durable than the strongest steel in the world, you can watch documentaries about this online. Moreover, the elevator will rise at a speed of 200 km/h, which means reaching a height of 36 thousand kilometers in just a week.
It is difficult to say who will allocate money for such a project. After all, the development of a space elevator has been going on for many years, starting with theories about this at the beginning of the 20th century.
Usually, such ambitious projects are taken over by NASA employees, but now they, like the United States as a whole, have huge problems in the economic sphere.
Will the Japanese be able to pull off such a mega-project? Will it be able to pay for itself and bring real profit? We will not be able to answer these questions. However, the very fact that the Japanese think in terms of tens of years ahead once again reminds us that planning is not the most strong trait Russian mentality.
As long as science is popularized in Japan this way, there is no need to worry about their technological sector, which is closely connected with marketing and economics, which in turn feeds science.
The Japanese will build an elevator into space by 2050
This device will be capable of delivering people and cargo to space station, which will also appear in the future
The Japanese company Obayashi announced its plans to build an elevator into space by 2050. The Japanese promise that it will be able to rise to an altitude of 60,000 miles and deliver people and cargo to a space station, which will also appear in the distant future. ABC News reports.
Builders also guarantee that the new elevator will be safer and cheaper than the space shuttle. Currently, sending one kilogram of cargo by shuttle costs approximately $22,000. And the Obayashi sci-fi device will be able to transport up to 200 kilograms for the same money.
Management construction company believes that the emergence of this transport system will become possible with the advent of carbon nanomaterials. According to Obayashi executive Yoji Ishikawa, the elevator cables will be futuristic nanotubes that are a hundred times stronger than those made from steel. Right now we are not able to create long cables. We can still make 3-centimeter nanotubes, but by 2030 we will succeed, he said, adding that the elevator will be able to deliver up to 30 people to the space station in just a week.
Obayashi believes its elevator will revolutionize space travel. The company involves students from all universities in Japan to work on this project. She also hopes to collaborate with foreign scientists.
Japanese elevators are considered one of the best in the world. A Japanese company is also currently developing the fastest elevator on Earth. Hitachi will provide it to one of the Chinese skyscrapers. This elevator will be capable of reaching speeds of up to 72 kilometers per hour and rising to a height of 440 meters, that is, up to the 95th floor.
About fifty years ago, people believed that by our time space flights would be as accessible as traveling on public transport back in their day. Unfortunately, these hopes did not come true. But perhaps already in 2050 it will be possible to get into space by elevator - the concept of this vehicle was presented by the Japanese company Obayashi Corporation.
Elevators are different! There is a regular elevator, there is an elevator in the bathroom, there is an elevator inside an aquarium, and the Obayashi Corporation promises to launch an elevator into space in a few decades! In fact, by creating similar technologies is carried out by several scientific and engineering groups around the world, supervised by the NASA space agency. However, according to the Japanese, this process occurs very slowly, so Obayashi Corporation decided to independently develop a space elevator.
The main achievement of NASA competitions is that they proved the very possibility of creating a space elevator. Obayashi Corporation promises to launch this unusual vehicle by 2050!
This elevator will lead from Earth to the space station, located at an altitude of 36 thousand kilometers. But the length of the cable will be 96 thousand kilometers. This is necessary in order to create an orbital counterweight. In the future, it can be used to extend the elevator route.
News Scientists are ready to build a diamond elevator into space you can read on your phones, iPad, iPhone and Android and other devices.
Scientists at Pennsylvania State University have discovered a way to create ultra-thin diamond nanothreads that would be ideal for lifting a space elevator to the Moon. Experts have previously suggested that diamond nanothreads could be an ideal material for creating a cable for an elevator into space.
The team, led by chemistry professor John Bedding, subjected isolated benzene molecules to alternating pressure cycles in a liquid environment. The specialists were amazed at the result, when the carbon atoms assembled into an ordered and neatly constructed chain. Scientists have created nanothreads 20 thousand times smaller than human hair. However, it is diamond chains that may be the strongest material on Earth.
More recently, a team from Queensland University of Technology in Australia simulated the layout of diamond nanothreads using large-scale molecular dynamics studies. Physicists have come to the conclusion that such a material is much more flexible in the future than previously thought, if the molecular structure is chosen correctly.
Scientists assumed that elongating the diamond thread could ultimately make the resulting material very brittle, but research has proven the opposite. Therefore, carbon nanofilaments have a great chance of being used in space, including as a cable for an elevator to the Moon, the concept of which was first proposed back in 1895.
Sources: spaceon.ru, www.bfm.ru, dlux.ru, news.ifresh.ws, mirkosmosa.ru
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One of the serious obstacles to the implementation of many stellar projects is that, due to their enormous size and weight, the ships cannot be built on Earth. Some scientists propose collecting them in outer space, where, thanks to weightlessness, astronauts can easily lift and move incredibly heavy objects. But today critics rightly point to the prohibitive cost of space assembly. For example, the complete assembly of the International Space Station will require about 50 shuttle launches, and its cost, taking into account these flights, is approaching $100 billion. This is the most expensive science project in history, but the construction in outer space of an interstellar space sailboat or a ship with a direct-flow funnel would cost many times more.
But, as science fiction writer Robert Heinlein liked to say, if you can rise 160 km above the Earth, you are already halfway to any point in the solar system. This is because with any launch, the first 160 km, when the rocket strives to escape the bonds of gravity, “eat up” the lion’s share of the cost. After this, the ship, one might say, is already able to reach either Pluto or further.
One way to dramatically reduce the cost of flights in the future is to build a space elevator. The idea of climbing to the sky using a rope is not new - take, for example, the fairy tale “Jack and the Beanstalk”; a fairy tale is a fairy tale, but if you take the end of the rope into space, the idea could well come true. In this case, the centrifugal force of the Earth's rotation would be enough to neutralize the force of gravity, and the rope would never fall to the ground. She would magically rise vertically and disappear into the clouds.
(Imagine a ball that you spin on a string. The ball does not seem to be affected by gravity; the fact is that the centrifugal force is pushing it away from the center of rotation. In the same way, a very long rope can hang in the air due to the rotation of the Earth.) There is no need to hold the rope; the rotation of the Earth will be enough. Theoretically, a person could climb such a rope and rise straight into space. Sometimes we ask physics students to calculate the tension in such a rope. It is easy to show that even a steel cable cannot withstand such tension; It was in this regard that for a long time it was believed that a space elevator could not be realized.
The first scientist to become seriously interested in the problem of the space elevator was the Russian scientist-visionary Konstantin Tsiolkovsky. In 1895 ᴦ. inspired by the Eiffel Tower, he imagined a tower that would rise straight into outer space and connect the Earth with a “star castle” floating in space. It was supposed to be built from the bottom up, starting from the Earth, from where engineers would slowly build a space elevator to the heavens.
In 1957 ᴦ. Russian scientist Yuri Artsutanov proposed a new solution: to build a space elevator in reverse order, from top to bottom, starting from space. The author imagined a satellite in geostationary orbit at a distance of 36,000 km from the Earth - from the Earth it would appear motionless; from this satellite it was proposed to lower a cable to Earth and then secure it at the lowest point. The problem is that the cable for a space elevator would have to withstand a tension of about 60-100 GPa. Steel breaks at about 2 GPa of tension, which defeats the purpose of the idea.
A wider audience was introduced to the space elevator idea later; in 1979 ᴦ. Arthur C. Clarke's novel The Fountains of Paradise was published, and in 1982. - Robert Heinlein's novel “Friday”. But since progress in this direction has stalled, it has been forgotten.
The situation changed dramatically when chemists invented carbon nanotubes. Interest in them increased sharply after publication in 1991. by Sumio Iijima of Nippon Electric. (It must be said that the existence of carbon nanotubes has been known since the 1950s, but they were not paid attention to for a long time.) Nanotubes are much stronger, but at the same time much lighter than steel cables. Strictly speaking, their strength even exceeds the level required for a space elevator. According to scientists, carbon nanotube fibers should withstand pressures of 120 GPa, which is significantly higher than the all-important minimum. After this discovery, attempts to create a space elevator resumed with renewed vigor.
B 1999 ᴦ. a major NASA study was published; it envisioned a space elevator in the form of a ribbon approximately one meter wide and about 47,000 km long, capable of delivering a payload weighing about 15 tons into orbit around the Earth. The implementation of such a project would instantly and completely change the economics of space travel. The cost of delivering cargo into orbit would immediately decrease by 10,000 times; Such a change cannot be called anything other than revolutionary.
Today, delivering one pound of cargo into low-Earth orbit costs at least $10,000. Thus, each shuttle flight costs about $700 million. A space elevator would bring delivery costs down to $1 per pound. Such a radical reduction in the cost of the space program could completely change the way we think about space travel. With a simple press of a button, you could launch an elevator and ascend into outer space for the same amount of money as, say, a plane ticket.
But before we build a space elevator that can easily take us to the skies, we have to overcome very serious obstacles. Today, the longest carbon nanotube fiber produced in the laboratory is no longer than 15 mm in length. A space elevator would require nanotube cables thousands of kilometers long. Of course, with scientific point This is a purely technical problem, but it is an extremely important one to solve, and it can be stubborn and difficult. Nevertheless, many scientists are convinced that it will take us several decades to master the technology for producing long cables from carbon nanotubes.
The second problem is essentially that, due to microscopic disturbances in the structure of carbon nanotubes, obtaining long cables may be generally problematic. Nicola Pugno from the Politecnico di Turin estimates that if even one atom in a carbon nanotube is out of place, the strength of the tube can immediately decrease by 30%. Overall, defects at the atomic level can rob a nanotube cable of 70% of its strength; wherein permissible load will be below the minimum gigapascals, without which it is impossible to build a space elevator.
In an effort to spur the interest of private entrepreneurs in the development of a space elevator, NASA announced two separate competitions. (The Ansari X-Prize competition with a prize of $10 million was taken as an example. The competition successfully fueled the interest of enterprising investors in the creation of commercial rockets capable of lifting passengers to the very edge of outer space; the announced prize was received in 2004 by the SpaceShipOne ship.\"7d NASA competitions are called Beam Power Challenge and Tether Challenge.
To win the first one, the research team must create mechanical device, capable of lifting a load weighing at least 25 kg (including its own weight) up a cable (suspended, say, from the boom of a crane) at a speed of 1 m/s to a height of 50 m. The task may seem simple, but the problem is that this device must not use fuel, batteries or electrical cable. Instead, the robot lift must be powered by solar panels, solar reflectors, lasers or microwave radiation, i.e. from those energy sources that are convenient to use in space.
To win the Tether Challenge, a team must submit two-meter pieces of tether weighing no more than two grams each; Moreover, such a cable must withstand a load 50% greater than the best example of the previous year. The goal of this competition is to stimulate research into developing ultra-lightweight materials strong enough to be stretched 100,000 km into space. The winners will receive prizes of $150,000, $40,000 and $10,000. (To emphasize the difficulty of the task, in 2005 - the first year of the competition - no one was awarded the prize.)
Of course, a working space elevator can dramatically change the space program, but it also has its drawbacks. Thus, the trajectory of satellites in low-Earth orbit is constantly shifting relative to the Earth (because the Earth rotates beneath them). This means that over time, any of the satellites could collide with a space elevator at a speed of 8 km/s; this will be more than enough to break the cable. To prevent a similar catastrophe in the future, it will be necessary either to provide small rockets on each satellite that would allow it to bypass the elevator, or to equip the tether itself with small rockets so that it can move out of the path of the satellites.
At the same time, collisions with micrometeorites can become a problem - after all, the space elevator will rise far beyond the Earth's atmosphere, which in most cases protects us from meteors. Since such collisions cannot be predicted, the space elevator will have to be equipped with additional protection and perhaps even fault-tolerant backup systems. Atmospheric phenomena such as hurricanes, tidal waves and storms can also pose a problem.
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 what we saw in Paris Eiffel Tower, 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 durable materials that prevent compression - but modern ideas space elevators are still considering 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 are currently recognized as the strongest material, and the only one suitable for building an elevator in the form of a cable extending from a geostationary satellite, the strength of nanotubes obtained in the laboratory is not yet sufficient 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 more cheap ways delivering 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 the difficult economic situation of the last couple of decades.
Ishikawa is confident that although an idea of this magnitude can most likely only be realized through international cooperation, Japan could well become its driving force 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.
