Therefore, in the future, space elevators will be built, whether from the perspective of saving time and effort, or its huge capacity, which can start with tons of units, as well as a large number of people to transport people to space, this advantage is incomparable with ordinary space fighters.

So the space elevator will gradually be phased out in the future, but for now, it is indeed a necessity.

And the main difficulties and solutions of the space elevator, before coming here, the origin has given a set of reasonable solutions.

First of all, the ground station, the difficulty of the construction of the ground station lies in the selection of the address, the fixing of the cable and the construction on the sea surface.

First of all, the ground station should be built at the equatorial IQ, and the climate of the site should meet the requirements of perennial winds below level 2, no cloud aggregation such as cumulonimbus clouds that can produce thunderstorms, and the principle of various pressure zones and monsoon circulation.

In addition to the climate, it is also necessary to take into account the extreme occurrence of cable breakage, so the location of the ground station should be far away from the gathering place of human beings, just like an airport, which is generally built in the suburbs, in addition to noise and other problems, the most important thing is to avoid the damage caused by aircraft breakdowns and crashes to residential areas.

And the crust in this area should be stable and strong enough to hold the cables away from earthquakes.

There is a lot of information that the equator east of the sunshine 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 a counterweight cable up to 36,000 miles or even longer, and the depth of the cable buried wire has very high requirements.

At the same time, the ground station also participates in sharing stress and oscillation, and the ground station also needs a taller tower structure to keep the cable upright.

Therefore, in order to meet the above requirements, Datang Technology needs to build an ultra-high tower as an anchor, the overall height of this tower must be at least 480 meters, part of which is used to fix anchors under the sea surface, and the other part is used to cope with the stress and swing of the cable.

The problem of construction work in the sea is actually not very difficult, because the "Nantianmen" project is the construction and assembly on the bottom of the Pacific Ocean, and for the operation under the ocean, intelligent robots are fully capable of this task.

Therefore, the origin lies in the preparation of selecting a place with a suitable texture and relatively stable seabed by comparing the 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 or more, which can be achieved through reclamation, and a larger area can meet its needs as an air-ground transportation hub with seaports, airports and even roads and bridges, and set up supporting cities around to meet the various service requirements required by loads or passengers.

So at present, it is necessary to have a piece of seawater with a small depth and a hard seabed that can provide enough tension to pull the cable and prevent it from flying out.

Another point is the problem of cables.

The cable is one of the most important structures in the space elevator, which needs to have a large radius, extremely high strength and corrosion resistance, and shear resistance and fatigue resistance. qq

One of the solutions is the material, which has been selected as a high-strength, high-heat-resistant composite fiber as the cable of the space elevator - PBO (poly-terenebenzene benzobioxazole), also known as Chailong fiber.

This is a kind of material produced by Amejian in the 80s of the last century for aerospace, but the breaking length of Chailong fiber is only 384 kilometers, which is only 1100 of the minimum target length, and the cost is also very high.

At present, the most suitable material for application is something called carbon nanotubes.

Carbon nanotubes, also known as bucky tubes, are one-dimensional quantum materials with a special structure (nanometer in radial size, micron in axial size, and basically sealed at both ends of the tube).

Carbon nanotubes are mainly composed of carbon atoms arranged in a hexagonal shape, and are composed of several to dozens of layers of coaxial round tubes. Keep a fixed distance between layers, about 0.34nm, and the diameter is generally 2~20nm.

The tensile strength of carbon nanotubes is 118.9±4.5 GPa, the breaking strain is 16.41±0.22%, and the toughness is 8.0±0.2GJm3.

A space elevator cable must withstand a tension of about 60-100 GPA (gipascal), and steel will break when it is about 2 GPA, so carbon nanotubes are a more suitable material.

And the lifetime of carbon nanotubes is very high, because the lifetime of carbon nanotubes is almost independent of the frequency of loading, which means that sample defects are instantaneous and the time required for crack propagation is negligible.

In other words, the fatigue failure process occurs suddenly, there is no gradual damage, there is no damage accumulation process, and the fatigue life of carbon nanotubes mainly depends on the generation time of the initial defect.

However, the fatigue behavior of carbon nanotubes is related to temperature, and higher temperatures will lead to a decrease in the fatigue resistance of carbon nanotubes, while at low temperatures, they will show higher toughness.

The earth's atmosphere will continue to weaken with the increase of altitude, and the temperature will gradually decrease, which can be said to be perfectly consistent with the fatigue behavior of carbon nanotubes.

At present, carbon nanotubes have not yet been put into use, and the longest carbon nanotubes can only be produced by 50 centimeters, which is far from the actual use or even manufacturing of cables.

Therefore, Ye Fan also plans to invest a sum of money to carry out research and development of carbon nanotube-related industries, and then exchange relevant technologies in the system, and it is only a matter of time before the results are produced.

The plan of the space elevator must be placed behind the floating city of the "South Tianmen" plan, that is to say, after the completion of the third phase of the project, the relevant life support system will be done, and the floating city can fly directly into space and become the largest space station in the world's history.

Therefore, at this time, the installation of space elevators will be carried out in space, such as the installation of synchronous orbital stations first, and then the cables will be lowered, and then the ground station and other projects will be carried out.

In practice, it can also be calculated that when the mass is evenly distributed, the maximum stress is concentrated in the synchronous orbital station, which means that if all the cables have the same cross-section, the material capacity of the first half will be greatly wasted.