Taking an elevator to Mars? This dream is not far away

Get into the elevator, press the up button and you'll be in space. Isn't that cool?

On November 21, Science and Technology Daily published an article on page 2 titled "Take an elevator to Mars? This dream is not far away."

The article points out that at the 2022 International Symposium on Peaceful Uses of Space Technology (Health) held from November 18 to 20, Peter Swan, chairman of the International Space Elevator Consortium and academician of the International Academy of Astronautics, proposed that in the future, space elevators, as permanent logistics infrastructure, can transport materials and personnel into space, becoming a new channel for entering space.

With a space elevator, it may only take 61 days to get to Mars

The principle of building a space elevator is not complicated. A long cable is suspended between heaven and earth, with one end fixed to the ocean at the equator of the earth, and the other end "grabbing" a counterweight (such as a satellite or space station) in geosynchronous orbit . Along the cable, a machine (the cabin of the space elevator) can move up and down.

According to the current design, the space elevator car weighs about 20 tons and has a climbing speed of about 200 kilometers per hour. In the future, as the cable is lengthened and the car's climbing speed is increased, it is expected to reach the geosynchronous orbit in 8 days, the moon in 14 days, and Mars in 61 days. "

Compared with rocket transportation, space elevators are powered by solar energy and do not consume large amounts of chemical fuel like launching rockets . Therefore, they are more environmentally friendly, less costly, and have a higher reuse rate. Therefore, they are also called the "Green Sky Road."

And the possibility of space elevators generating space debris is extremely small. Scientists have found that as of January 2020, there are 29,000 pieces of space debris larger than 10 centimeters and more than 170 million pieces larger than 1 millimeter, which seriously pollute the space environment.

In addition, the cost of transporting materials using a space elevator is about $500 per kilogram, which is cheaper than using a rocket.

Swan believes that in the future, humans will need to launch large amounts of supplies into space to build villages on Mars and the Moon. Interstellar travel is also highly anticipated, and space elevators are very commercially competitive.

But rocket launches will not be abandoned. Rockets are faster than space elevators and can quickly cross the radiation belt, so some people have proposed using the "space elevator + rocket" method of transportation to achieve complementarity.

If you think of the space elevator as a cargo ship, then the rocket is a cargo plane.

The design is feasible, but there are still challenges in practice

The dream of a space elevator is old. In 1895, Russian scientist Konstantin Tsiolkovsky proposed the idea of ​​a space elevator after seeing the Eiffel Tower. Science fiction master Arthur Clarke also described a space elevator in his novel The Fountains of Paradise. However, due to technical obstacles, the space elevator remained in the conceptual stage for a long time.

With the continuous development of aerospace technology, there are more possibilities for building space elevators. In terms of materials, carbon nanotubes and super-strong graphene are considered to be ideal materials for building space elevator cables; in terms of design, scientists have currently proposed eight relatively stable and reasonable scientific design plans; in terms of engineering, scientists in some countries have carried out some small experiments and are preparing for in-depth verification.

Of course, there are still many challenges in theory, technology and engineering, such as dynamics and control methods, new material research and development, equipment design and construction, etc.

Students watching the third lesson of "Tiangong Classroom"

Many details are yet to be answered by scientists and engineers: What drive mode should be chosen for the space elevator car? How to overcome the influence of gravity? How can the cable withstand the bombardment of high-energy cosmic rays and effectively resist swinging? What should be done if the elevator encounters space debris and meteorites?

Scientists estimate that the space elevator will be put into initial operation around 2035. Using the space elevator to carry people will need further verification to ensure its safety and feasibility. It may not be possible until around 2045, but there is no definite timetable yet.

Shao Ting, trainee reporter at Chengshi Interactive

Content summary: Science and Technology Daily, Page 2

Image source: Xinhua News Agency