How far is the space 3D printing from us?

In the process of human exploration of the universe, the "supply line problem" of equipment and materials has always hindered human flying to a farther space. When humans are in a space except for space vessels Using existing equipment and space raw materials to manufacture the tools required. At this time, 3D printing becomes a good choice.

3D printing technology, also known as additive manufacturing, is based on digital model files. It uses powder granular inorganic or organic such as adhesive materials to construct objects to construct objects by layer printing. With the acceleration of human exploration of outer space, 3D printing technology is very suitable for the process of manufacturing from simple to complex and from scratch.

Figure 1 Human establishment of a moon base imagination map (picture source: VEER gallery)

What can space 3D printing do?

September 3D printing mainly solves two aspects:

(1) Help to run and maintain the spacecraft during the flight. Mainly include: replace parts for spacecraft in space manufacturing, expand the life of the spacecraft, and save repetitive launch costs; the use of materials for materials can be directly used to use aging and waste materials to return to the furnace. Garbage manufacturing parts can save costs and environmental protection; super large -sized components optical lens that is difficult to launch on the ground in space manufacturing.

(2) Establish a space base suitable for human survival. When humans reach the new planet, they must be resolved. First of all, solve the problem of living, you can print the houses suitable for human living on the spot. The structure of the house needs to have thermal insulation function, and it can resist tiny fluid attacks and cosmic ray radiation. Then consider eating, print the sun room suitable for plant growth to plant food. The last is to print the transportation that humans can visit each other.

Where is the main difficulty of space 3D printing?

3D printing in space is absolutely not easy. When the spacecraft flys on orbit, it will be disturbed by various effects other than the gravity of the earth, such as atmospheric resistance, solar radiation light, gravity gradient effect, rail mobility, posture control, equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment operation and equipment. Incorrect activities, so as not to reach the state of "weight loss", but a "micro -gravity" environment.

Similarly, when building a space base in the new planet, it mainly considers the vacuum or atmospheric environment, solar radiation, gravity, etc., such as: the gravity of the moon is only 1/6 of the earth, which is the vacuum environment; the gravity of Mars is 2 /5, mainly carbon dioxide gas.

Although the basic design of the 3D printer remains unchanged, the micro -gravity and atmosphere environment requires special consideration. Therefore Under the imperfect situation, the design of 3D printing equipment is as simple as possible as possible, and the requests are as reduced as much as possible.

Which methods are suitable for space 3D printing?

The 3D printing process is nothing more than combining a micro -drop containing solid fluid into the three -dimensional three -dimensional material we want. There are many 3D printing methods (Figure 2), but not all methods are suitable for space 3D printing. Under the vacuum micro -gravity conditions outside the space station and spacecraft, which materials can be printed at a glance at a glance.

Under the premise of minimizing the requirements of the printing conditions, those who contain liquids in the process can basically be eliminated, because liquids can easily boil and evaporate under the condition of vacuum low vapor pressure, especially under micro -gravity conditions, it is difficult to maintain the original form. Therefore, some slurry printing methods are low feasible, such as liquid optical curing printing method (SLA).

There is also a printing method that requires powder to participate. In the vacuum micro -gravity environment, it is difficult to spread the pink body without gravity, and it is easy to fly around. Election area laser melting (SLM) and sintering (SLS) printing methods, electron beam melting and sintering printing methods, and adhesive jet printing methods (BJ) can basically be excluded.

Figure 2 Dragons of various 3D printing methods (Picture Source: Reference [1])

Internationally uses silk materials as the main material form of space manufacturing. It mainly uses the method of melting deposition (FDM) to achieve space 3D printing. The basic principle is to heat the heating head to heat the hot melt material to the critical state, so that it is half half of the presence The fluid state instead of liquid state, and then the heating head will move along the two -dimensional geometry trajectory determined by CAD under the software control. At the same time, the nozzle is squeezed out of the material of the semi -flow state. To.

Judging from this printing characteristics, there will be no liquid and powder in the entire method process. The raw materials will become a semi -current solid state under heating conditions. More harsh heating methods. This method is the simplest and feasible.

Figure 3 FDM printing principle and printing device (picture source: left Figure Wikipedia, on the right picture Veer gallery)

On May 7, 2020, China conducted the first rail 3D printing test, and it was also the first time in the world to achieve space 3D printing with continuous carbon fiber enhancement composite materials (Figure 4). The technology adopted is the melting deposition (FDM) 3D printing technology. The raw materials used are resin -based continuous carbon fiber enhanced composite materials. Under the condition of heating, the resin plastic is melted into a semi -current state. Together, get the complex structural parts you want. Figure 4 China's first space 3D printing continuous carbon fiber composite material (picture source: China Space Technology Research Institute)

Human exploration of the establishment of a space base

Building a space base in the planet, because there are certain gravity conditions, the printing of the powder is relatively feasible. Under a closed atmosphere, liquid printing can also be completed. The moon and Mars have the conditions to create such an environment.

The industrial associations composed of the European Space Agency and Alta SPA, Monolite Co., Ltd., Foster Architect and San Anna Higher Research Institute adopted the adhesive jet 3D printing technology of D-SHAPE (Figure 5) to evaluate the construction base at the moon construction base. Feasibility [2].

They first simulated a closed environment of an ambient temperature of 20 ° C and a vacuum at 2KPa, and through theoretical calculations, under this condition, as long as the diameter of 200 μm below 200 μm (ink) is sprayed on the moon soil layer (73%of the grains (73%of the grains) The diameter is less than 150 μm, and 81%of the particle size is less than 250 μm). The droplets will not evaporate, and the liquid state can be maintained for a long time to make the moon soil form a mesh structure. In the end, the component was printed with a moon -like volcanic ash. After the test, the result was very good. It had the same low pore rate as the concrete, and the compatible hardness was very good.

Figure 5 Building printed by D-Shape (6m × 6m × 6m) (Picture Source: Reference [3])

my country has also explored the use of 3D printing technology to simulate the construction of a moon base. In 2021, the Ministry of Science and Technology included the "Lightweight Reconstruction of Moon Construction Methods" into a key research and development plan, becoming a key project for "engineering science and integrated cross".

Huazhong University of Science and Technology has become the chief scientist unit of the project. They named the moon base style built on the moon as "Monthly", which is a building that looks like an egg shell. It is planned to burn the moon brick with a moon soil, and then use the "Moon Spider" robot to mix [4], and the 3D printing model "Month".

From the outside, it looks like an enlarged egg shell standing on the ground. As a building, there is no load -bearing "four beams and eight pillars" in the "Monthly Pot". At the top of the egg shell is the dome structure. The eggshell body is divided into two layers in the inner and outer and outer layers. A layer similar to the ribs in the middle to enhance stability.

The team combines the construction method of traditional Chinese brick masonry with the 3D printing and construction method. The melting sintering monthly soil, paving a layer of moon soil and melting a lunar brick with a tenon -and -mortise structure, and then assembling the moon bricks through the robot. The whole process avoids the risk of one -time 3D printing by sintering monthly bricks, and then built by the robot and reinforced the connection with 3D printing to complete the structure to avoid structural deformation. At present, they have prepared the first domestic simulation monthly vacuum sintering printed sample, and achieved a major breakthrough from "0" to "1".

Figure 6 "Month Bo Zun" Moon Base Effect Chart (Picture Source: National Digital Construction Technology Innovation Center)

Plan for human space printing the moon base

NASA (National Aerospace Agency) will enable 3D printing technology in the Artemis plan. They will call it a peak of "Eternal Light" at the Antarctic Light of the Moon (the location is close to the edge of the crater, it is the ubiquitous solar radiation at everywhere, everywhere is everywhere. The place where the sun is in the area is very low, which can provide long -term lighting for solar collection. The permanent shadow volcanic mouth area is also conducive to the collection of water.) Members and robots provide a life and workplace.

It will consist of 3 units, 75 square meters per unit, and is separated by a 90 -square -meter public courtyard and integrates a photovoltaic tree to directly capture and harvest solar energy. Its span is 8 meters × 9.4 meters and a height of 5 meters. It can protect astronauts from radiation, lunar earthquakes, extreme thermal changes, and meteorites. The design life is at least 50 years. At present, the first prototype is built in the Kennedy Space Center, and the 3D printing material is based on the BP-1 moon model. The temperature range from -170 to 70 ° C [5].

NASA plans to perform this task in 2028. They hope that this will make them have new science and technology discovery to establish a moon economy. It is important to explore Mars and maintain a long existence of humans. The goal of NASA is to perform this task in 2028. They hope that this project can integrate the latest scientific and technological achievements in order to establish a normal lunar base, realize the possibility of human long time in space, and log in to humans to log in Mars is prepared.

Figure 7 3D Printing LINA Monthly Emperors Base Imagination (Picture Source: AI SpaceFactory) my country has a more ambitious plan, that is, after the launch of the moon, it will also build an international moon scientific research station. In March 2021, my country and Russia officially signed a memorandum of cooperation to jointly build a moon base. At present, the moon Antarctica will be the best location for the construction of the moon base. Only when the moon base is built, human beings are expected to obtain the most important resource on the moon-氦 -3. If it is used for controllable nuclear fusion, its energy is enough to use it for more than 10,000 years! Moreover, the gravity on the surface of the moon is only 1/6 of the earth. In the future, rockets are launched here, and our spacecraft will fly further!

Conclusion

How far is space 3D printing from us? The answer to this question is that it can reach. The continuous development of space 3D printing will make the moon base that existed in science fiction movies to become a reality, and my country will also use this technology not far away to achieve more scientific imagination that was once impossible.

Produced: Popular Science China

Author: Chen Jian (Shanghai Academy of Sciences Shanghai Silicate Research Institute)

Producer: China Science Popularization Expo

references:

[1] Guo Liu, xiaofeng zhang, Jian Lv, Additive Manualing of Structural Materials, Materials Science & Engineering R, 2021 (145): 100596.

[2] Giovanni Cesaretti, Enrico Dini, Xavier de Kestelier, Building Components for An Outpost on the Lunar SOIL BY Means of a Novel 3d Printing Technology, Acta ASTRONAUTICA, 2014: 33): 3): 3): 3): 3): 3): 3): 3): 3): 3): 3): 3): 3): 3): 3).

[3] Hamad Al Jassmi, Fady Al Najjar, Abdel-Hamid Ismail Mourad, Large-SCALE 3D Printing: The Way Forward, 2018 (324): 012088.

[4] Yang Jiafeng, cover the house on the moon, the academician team of Huazhong University of Science and Technology studied the robot and made the moonlight base, the Yangtze River Daily.

[5] David Malott, AI spacefactory releases designs for first human foothold on the moon, https://www.designboom.com/technology/ai-spacefactory-nasa-lina-first-human-foothold-on-moon-07- 04-2022.

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