China would like to build a spacecraft more than a kilometer long!

China has ever more devouring space ambitions … According to documents published by the Mathematics Department of the National Natural Science Foundation of China (NSFC), Beijing plans to build space bases over a kilometer long described as ” a major strategic aerospace equipment for the future use of space resources, for the exploration of the mysteries of theuniverse and for long term life in orbit“. For comparison, the International Space Station (ISS) is only 110 meters long, and cost a whopping $ 150 billion.

Inhabited station or solar power plant

Although still enough vague, the project could fulfill several functions such as serving as a télescope spatial, to host manned missions or to act as a gigantic solar power plant where theenergy would be sent to Earth via microwave beams. Technology already tested by the US military and by China, which carried out last August microwave transmission tests from a ballon at an altitude of 300 meters. One can only wonder about the feasibility of such a juggernaut. Impossible, of course, to send such a mass at once. The rocket Falcon Heavy, one of the most powerful to date, can only carry a maximum of 63 tonnes of equipment. The International Space Station, which weighs nearly 2,800 tonnes, was assembled over several years.

New construction techniques in orbit

For Mason Peck, engineer at Cornell University and former director of technology at Nasa, the project is however perfectly realistic. ” I don’t see insurmountable obstacles, but rather problems of scale », He explains to the site Live Science. It all depends on the use that will be made of the structure: ” If we are talking about something that is just very long and not so heavy [qu’une structure habitée], it is possible “. New techniques of construction also could reduce the shipping cost. NASA, for example, is working on assembly in orbit of a giant space telescope where mirrors would be printed directly in space thanks to a technology called ALD (automatic layer deposition), consisting of printing and solidifying reflective layers on a substrate. The different mirrors could then be assembled directly in orbit using small robots. It would even be possible to stock up on materials premieres on the Moon, although this first requires build a dedicated moon base, which is not possible in the short term, advance Mason Peck.

A machine difficult to maneuver

The construction of the vessel is not the biggest obstacle facing the Chinese, however. ” Whenever a spacecraft is subjected to forces, whether by maneuvering or docking another vehicle, the movement gives energy to the structure which makes it vibrate and bend, explains Mason Peck. With such a large ship, these vibrations will take a long time to attenuate, so it is likely that it will need shock absorbers or other controls to dampen these vibrations “. In addition, in low orbit, atmospheric drag tends to slow down vehicles; it is therefore necessary to constantly readjust the altitude, which requires significant fuel consumption. And, of course, the heavier the structure, the more it takes.

The major question, however, remains that of cost. The allocated budget, which amounts to 15 million yuan (or just under 2 million euros for five projects in total), seems ridiculously low. Although it relates for the moment only to the phase of preliminary studies, it is squarely not up to the height of the colossal financing which would be necessary. As mentioned above, the ISS has cost 150 billion dollars and its maintenance swallows up more than 3 billion dollars per year. A one-kilometer-long vessel would thus perhaps be feasible technologically and in theory, but hardly feasible in practice.