Moreover, the purpose of the "space elevator" is to provide a way for people and goods to cross the earth's atmosphere, beyond some designs that do not use rockets. This idea was first put forward by Russian scientist Konstantin Tsiolkovsky in 1895.
Since then, the idea has been improved, but the basic settings have not changed. The elevator consists of a single-core cable, which is anchored at a fixed point on the earth (usually at the equator) and extends upward beyond the height of the geostationary orbit-about 35,786 kilometers.
At the top of the cable is a counterweight. The mutually balanced gravity and outward-directed centrifugal force help to keep the cable in a well-balanced and taut state, and provide a line along which the cargo hold or cargo hold can move up and down quickly.
The main problem with this idea is that the pressure on large cables will be so great that there is no cable strong enough to bear it at present. In addition to fighting the gravity of the earth, we must have enough speed, otherwise walking for a few days or months is too much for people, and the speed is too fast for the human body to bear. The magnetic levitation tube is unidirectional.
In the past decades, there have been several large-scale competitions and proposals aimed at providing designs aimed at overcoming this problem, but so far they have not been successful. The last time was in 20 14, Google X, the development department of Google, started a project, but when it was found that no one could make a carbon nanotube cable more than one meter at that time, the idea was shelved.
Carbon nanotubes are the hope of space elevator engineers, but the model provided by a study in 2006 predicts that destructive defects will inevitably appear in the nanotube cable with a length of about 654.38+ million kilometers, which will reduce its overall strength by about 70%.
Popescu and Sun proposed different methods in their new essays. Although carbon nanotubes are the ideal choice for space elevator cables in theory, they said that it is difficult to exceed several centimeters in length at present, so it is not practical. However, they pointed out that some composite materials (mainly carbon nanotubes alloyed with other materials) are weak at present, but "we are rapidly approaching the strength range of materials needed to stabilize large structures with self-repairing mechanism".
Self-repair mechanism is very important. The researchers put forward a cable solution-dividing the cable into two directions-forming a series of stacked sections upwards; On the side, it is arranged in a series of parallel filaments. When any filament fails, it must really limit its influence to its own part from time to time, and the load will be shared between its adjacent parts immediately until the maintenance robot enters the maintenance and replaces it.
The researchers wrote that having an "autonomous repair mechanism" can ensure reliability at high gravity levels, while allowing the use of lighter materials for construction, thus bringing the practical feasibility closer.
On the basis of all these models, popescu and Sun believe that the new space elevator model is based on the gradually decreasing stress ratio, which shifts from the engineering standard level to the biological level. They point out that human tendons and spines can withstand huge stresses that are very close to tensile strength-much greater than those allowed by steel engineers.
Personal space vehicle
This is the most comfortable, simple and convenient way, just like a car, you need to get a driver's license. Travel between the earth and space, plan a specific route, parallel.
erect
"A thousand blows are still strong, and the wind blows east, west, north and south." This is the green and tender bamboo standing up straight, showing you its power;