Who will ride the elevator to space?

Scientists around the world estimate that the field of nanotechnology will enable an impressive leap forward in the development of the human race; The question is whether humanity will know how to use the new technology, and how

by Debbie Kaufman *

In June '92, Dr. Eric Drexler was invited from his office in San Francisco to Capitol Hill in Washington, to testify before a subcommittee of the US Senate on Science, Technology and Space Affairs. Drexler introduced the field of molecular nanotechnology in the discussion, noting that this field will be one of the main instruments for scientific and economic growth in the coming years.

This was the first time that the American government was exposed to the capabilities hidden behind nanotechnology (nano - one billionth of a meter), which deals with molecules and atoms. The administration was not convinced to invest in the new field in that discussion. However, even then buds of the ability to create materials in nanometer sizes appeared. Today it is known that it is indeed possible to produce materials, components and medicines in nanometer sizes. The American government was also convinced, and in 2002 the field of nanotechnology received the status of a national project with a budget of 519 million dollars.

One of the main reasons why the field gained momentum is economic. Already when Drexler met with the heads of government in '92, he estimated that nanotechnology could reduce the construction of houses, sailboats, spaceships and weapons by about 50%; This, because the nanometric materials will be assembled by humans, who will be able to manipulate any existing material.

This option may solve problems of lack of resources and natural treasures and save production costs. Scientists predict that this is the biggest technological leap in the history of the human race.

Drexler stated at the meeting that "it is very difficult to describe a future scenario in which we do not have these technologies (nano-technologies - DC)". Indeed, it seems that the US is making considerable efforts to invest in the field, and that nanotechnological research is progressing relatively quickly.

"This is no longer science fiction"

However, in light of the promise inherent in nanotechnology, the question arises as to what its uses will be; That is, if and how humanity will be able to use the new technology. One of the examples of this is the space elevator that is currently being developed by the American space agency NASA. The project began to gain momentum in the last two years, due to studies that showed that it is possible to produce an electromagnetic strip made of carbon nanomolecules, which is needed to create the elevator.

In '99, a senior NASA official, David Smitherman, published an article entitled "Space Elevator: Advanced Space Infrastructures for the New Millennium", in which he stated that "this is no longer science fiction", and that the agency has "results showing that this is possible". According to him, scientists, engineers and government officials have already started working on suitable infrastructure for the elevator, which should be available in less than 50 years.

The idea, in the end, is to develop transportation between the Earth and space, which will make it possible to maintain commerce, services and, in fact, a whole life on other planets; Because only if such a life develops, there will be justification for the investments involved in building an elevator to space.

The elevator is actually a long cable that stretches from the earth to a height of 35,786 km. Electromagnetic machines or robots, which will wander around the cable, will be able to move people, machines and rockets from Earth to space, and vice versa. The main problem the program suffers from is the question of justifying the investment. This is a huge investment of billions of dollars, NASA claims, and therefore they are trying to promote the project carefully.

The major expenses include a launching station for the elevator, which should rise to a height of at least 50 km. This tower must be made of special, extremely light materials that can withstand the force of gravity. From the end of the tower will come the special cable, which will lead the elevator into space. According to Smitherman, the project is not possible today, but in 50 years it will be possible to implement it.

A 106-year-old idea

In the article published by Smitherman, the scientist mentions the writer Arthur C. Clarke, who included in the novel "Fountains of Paradise" published in '78 a story about engineers who developed space elevators in legendary regions. In his book, Clark describes new materials, made of carbon fibers, which made possible the construction of space elevators. Smitherman points out that these materials are currently in research laboratories.

But it turns out that Clark was not the first. Already in 1895, a Russian scientist named Konstantin Tsiolkovsky proposed an imaginary "heavenly castle" that would be geosynchronous and move in a fixed orbit in space and launch to Earth. He got the inspiration for the story after watching the Eiffel Tower, and imagined the tower from its top down.

In 1960, a Russian engineer from Leningrad, Yuri Artsonov, stated that it was possible to build space elevators, but his words were not appreciated. It wasn't until 75 that the idea of ​​space elevators gained attention from the Western scientific community, thanks to an article written by Jerome Pearson from the US Air Force Laboratory on the matter.

But it wasn't until 99, when Jerome Pearson proposed the space elevator as a tool to reduce the costs of launching into space, that NASA decided to promote the matter. According to Pearson, launching one kilogram into space costs about 22 thousand dollars today. On the other hand, the use of the space elevator will reduce the price to less than 1.5 dollars per kg.

In order to reach these costs, it is necessary to invest a lot of resources in developing technologies and materials that will significantly reduce the flight into space. Smitherman listed five technological developments that are required to make space flight cheaper; These, in his opinion, are critical to the success of the project.

According to a report published by NASA in '98, the pressure on the elevator will increase as you lift towards the exit from the atmosphere. Therefore, the elevator cable should be constructed of extremely strong materials, and subject to change in its thickness; That is, thick at the beginning and very thin at the end.

Materials such as steel and diamond, which today are considered particularly strong, do not allow the construction of a cable that will withstand the required loads and pressures. Diamond, for example, is composed of carbon atoms that form extremely strong three-dimensional covalent bonds, but its molecules tend to spread out in flat planes.

Molecules 100 times stronger than steel

This aspiration is problematic, if you want to bend the material into a ring, tube or curved structure. On the other hand, carbon atoms arranged in a different way - Nanotubes (Carbon CNT), for example - enable the construction of an extremely strong elevator cable. These molecules are considered 100 times stronger than steel, and weigh one-sixth as much.

The second technology is supposed to be one that will achieve control and control over the deployment of the cable from Earth to space. A third technology is required for the production of a structure from light and relatively cheap materials, which will justify the construction of extremely tall buildings on Earth, which will reach a height of 50 km.

A fourth technology is the development of electromagnetic power that will move a lot of weight at high speed, such as equipment for building infrastructure in space. This technology leads to the fifth field, which is the development of transportation, services and facilities that will support space structures; Without these, the whole plan will go down the drain.

A new-old idea: an elevator to space
Connect the Earth to a satellite in geostationary orbit

One of the amazing technological ideas with which the Office of Advanced Projects of NASA (the US space agency), located at the Marshall Space Base, has recently been "playing around" is the construction of an elevator that will fly from the surface of the earth to the height of a satellite's orbit. If he weaves skin and tendons, in the future we will be able to reach the space station, which will be placed at much higher altitudes than the international space station that is being erected now - but after a meager payment of about 200 dollars (elevator travel fee) - instead of 20 million dollars, which were probably paid to the operators of the "Mir" space station in order to house a distinguished guest in it for several days.

The elevator to space is not a new idea. Back in 1895, the Russian Chiolkovsky devised the construction of a tower very high off the ground - the top of which would carry a space station in geosynchronous orbit, at an altitude of 35,786 km.

Arthur C. Clarke, the science fiction writer, devised a similar device in his book "The Fountains of Paradise". But now the literary idea is being discussed quite seriously at NASA. The Americans are more practical - because we see on the horizon a solution to the cardinal problem that until now has posed obstacles to the realization of this vision: the material from which the orbital elevator cable will be built.

The first calculations in this regard were made in 1966. They showed then that there was still no particularly strong material (among the materials that were known at the time) that would be able to withstand the efforts and tear. In recent years, forms of arrangement of carbon atoms have been found in complex particles, some of which are strong enough to build the strongest cable in the world.

The special materials are tiny tubes, made of carbon atoms wrapped around a single long axis.

In the modern version of the space elevator, construction will begin from a space station that will be placed in geosynchronous orbit. The station "stands" above a certain point on the equator - and two cables made of carbon tubes begin to emerge from it. One cable descends towards the Earth's surface and the other is released towards space. The more cable that is released, the larger the diameter of the new cable that is released (to support the additional cable).

Close to the surface of the earth, at an altitude of 50 km, the descending cable will be connected to the top of a tall tower, carried by all the mountains on earth. This will be the base of the tower that will bring the passengers to the stars. The cables will not be used to transport cargo, but will only support the carriages that raise cargo and people into space, while similar carriages will descend, on the other side of the cable.

From the space station it will be possible to let the charges slide freely: the centripetal force of the earth's rotation and the elevator connected to it, will automatically throw the charges into space. There is no point in rushing and trying to find tickets for such space flights. The project is far from being ready for implementation. It will take at least a good few decades until the technological developments catch up with the imagination of the planners.

* The knowledge website was until 2002 part of the IOL portal of the Haaretz group