So things like space elevators will gradually be eliminated in the future, but for now, they are indeed a necessity.
As for the main difficulties and solutions of the space elevator, Origin has already given a set of reasonable solutions before coming here.
The first is the ground station. The difficulty of the ground station construction lies in the selection of the address, the fixing of the cables and the construction on the sea.
First of all, the ground station should be built on the equator IQ, and the climate of the site should be such that the wind is lower than level 2 throughout the year, and there is no accumulation of cumulonimbus and other clouds that can produce thunderstorms, and the principle of various pressure zones and monsoon circulation.
In addition to the climate, we must also consider the extreme occurrence of cable breaks. Therefore, the location of the ground station should be far away from the place where humans gather, like an airport, which is generally built in the suburbs, except for noise and other issues. The most important thing is to avoid damage to residential areas caused by aircraft failures and crashes.
And the crust in this area should be relatively stable and strong enough to secure cables and stay away from earthquakes.
There is a lot of information that the equator located east of the Rizhao line and west of the American continent is a more suitable site, and the axial tension provided by the ground station is used to fix and maintain up to 36,000 miles, or even longer. Heavy cables, and the depth of cable embedding has very high requirements.
At the same time, the ground station also participates in sharing the stress and swing, and the ground station also needs a higher height tower structure to keep the cable vertical.
Therefore, in order to meet the above requirements, Datang Technology needs to build an ultra-high tower as an anchor. The overall height of the tower must be at least 480 meters. One part is used for anchoring under the sea surface, and the other part is used to cope with cables. For stress and swing, in actual construction, the height of the ground and the ground can be reasonably allocated according to the situation.
The problem of carrying out construction operations in the sea is actually not that difficult, because the "Nan Tianmen" plan is to carry out construction and assembly on the seabed of the Pacific Ocean. For operations under the ocean, intelligent robots are fully capable of this task.
Therefore, the origin is to select a seabed with suitable texture and relatively stable place by comparing global hydrological data and geological data.
At the same time, in order to maintain its own structure, the ground station should have an area of at least 2KM. This can be achieved by reclamation. The larger area can be used as an air-ground transportation hub to configure seaports, airports and even roads and bridges and other transportation facilities, and Set up supporting cities around to meet the various service requirements required by loads or passengers.
Therefore, it is necessary to have a small seawater depth and a hard seabed that can provide enough pulling force to hold the cable and prevent it from flying out directly.
Another point is the problem of cables.
The cable is the most important structure of the space elevator. It needs to have a large radius, high strength and corrosion resistance, as well as shear resistance and fatigue resistance. The difficulty lies in how to bear the stress and how to Build.
One of the solutions is materials. At present, some people have selected a high-strength, high-heat-resistant composite fiber as the cable of the space elevator—PBO (poly-p-phenylene benzobisoxazole) is also called diesel. Long fiber.
This is a suitable material for aerospace and aviation produced by Aramco in the 1980s. However, the fracture length of Chalon fiber is only 384 kilometers, which is only 1100 of the minimum target length, and the cost is also very high. It is said that if this is the case, it will not be enough to sell Datang Technology.
At present, the material with the most application scenarios is something called carbon nanotubes.
Carbon nanotube, also known as bucky tube, is a one-dimensional quantum material with a special structure (the radial dimension is on the order of nanometers, the axial dimension is on the order of micrometers, and both ends of the tube are basically sealed).
Carbon nanotubes are mainly composed of carbon atoms arranged in hexagons to form coaxial circular tubes with several to tens of layers. Maintain a fixed distance between the layers, approximately, the diameter is generally 220nm.
The tensile strength of carbon nanotubes is 118.9±, the fracture strain is ±%, and the toughness is 8.0±. The stretching of the material is a nonlinear elastic behavior, which is consistent with the widely reported elasticity of carbon nanotubes.
A space elevator cable must withstand a tension of about 60-100gpa (Gipascal), and steel will break when it is subjected to about 2gpa, so carbon nanotubes have become a more suitable material.
Moreover, the life of carbon nanotubes is very high, because the life of carbon nanotubes is almost independent of the frequency of loading, which means that defects in the sample are formed instantaneously, and the time required for crack propagation is negligible.
In other words, the fatigue failure process occurs suddenly, there is no progressive damage, and there is no damage accumulation process. The fatigue life of carbon nanotubes mainly depends on the generation time of initial defects.
However, the fatigue behavior of carbon nanotubes has a certain correlation with temperature. Higher temperature will cause the fatigue resistance of carbon nanotubes to decrease, while at low temperatures they exhibit higher toughness.
On the other hand, the earth's atmosphere ~EbookFREE.me~ will continue to weaken with the increase in altitude, resulting in a gradual decrease in the thermal insulation effect, and this characteristic can be said to be perfectly in line with the fatigue behavior of carbon nanotubes.
However, the current carbon nanotubes have not yet been put into use, and the longest carbon nanotubes can only be produced at 50 cm, which is far from enough for practical use or even manufacturing of cables.
Therefore, Ye Fan also intends to invest a sum of money to conduct research and development on carbon nanotube-related industries, and then exchange related technologies in the system. It is only a matter of time before results are produced.
The space elevator plan must be placed after the floating city of the "Nan Tianmen" project. That is to say, after the completion of the third phase of the project, the relevant life-sustaining system will be completed, and the floating city can fly directly. Space has become the largest space station in the history of the world.
Therefore, at this time, the installation of space elevators is carried out in space. For example, the synchronous orbital station is installed first, the cables are lowered, and the ground station and other projects are carried out.
In fact, by calculation, it can be known that when the mass is evenly distributed, the largest stress is concentrated in the synchronous track station. That is to say, if all the cables are of the same cross section, the material capacity of the first half will be reduced. Will be greatly wasted.
