Superplasticizer News and Tech > Superplasticizer News > Building a base on the moon with astronauts' urine has its own flavor

Building a base on the moon with astronauts' urine has its own flavor

Superplasticizer News 2021-07-21 14:14 103
Popular science in China Production of

: Han Pei (Center for space application engineering and technology, Chinese Academy of Sciences)

Supervised by

: Computer Network Information Center, Chinese Academy of Sciences

The dream of earth people to explore the sea of stars has never stopped. The construction of planetary base in extraterrestrial space is the stepping stone for us to explore and survey the broader extraterrestrial space. China's National Space Administration, NASA and ESA all plan to build lunar bases in the next few decades

Concept map of

lunar base (image source: https://www.esa.int/ESA_ Multimedia/Images/2018/11/Future_ Moon_ base)

The construction of the base on the moon is divided into two steps: first, preparing raw materials for construction; 2、

seems very simple, but the moon is no worse than the earth. The environment is harsh: strong radiation, extreme high temperature, and even a meteorite may fall from time to time. To survive, we must build a strong fortress. It takes a lot of manpower and material resources to build a base on the earth, let alone on the moon

How to solve the manpower problem when building a base on the moon

With the current human technology, it is easy to send a person to the moon, but it is not easy to send a large number of people to the moon, and it costs a lot of financial and material resources

Is there a high-tech solution to the problem of manpower shortage

yes! 3D printing technology

3D printing is commonly known as additive manufacturing, which is a technology based on digital model file, using powder metal or plastic and other adhesive materials to construct objects by layer printing

Hand made model of

3D printing (image source: https://www.printplaygames.com/product/3d-printed-miniatures/ )

3D printed crafts (photo source: Chinese version) https://www.kateblacklock.com/3d-printed-ceramics/ )

Is 3D printing feasible for building houses

is feasible, and 3D printing technology has been commercialized. A 1100 square meter villa in Suzhou Industrial Park of China has created the world's first record of 3D printing with integrated interior and exterior decoration

3D printing is not only highly automated and labor-saving, but also supports remote control. Theoretically, it is possible to launch 3D printers and build tools and infrastructure before astronauts arrive on the moon

At present, many countries have put forward the idea of using 3D printing to build a base on the moon. For example, ESA proposes to use 3D printing method to mix the floating dust and water on the lunar surface to build lunar buildings. Russia also plans to use lunar dust or weathering layer as raw materials to build a lunar base using 3D printing technology

Concept map of

lunar base https://sputniknews.com/science/201812011070300348-russia-moon-base-lunar-exploration/

the future lunar base can be built with 3D printers, which can mix materials such as floating soil, water and astronaut urine on the lunar surface. Source: ESA, foster and partners

Concept map of

lunar base http://worldbuilding.stackexchange.com/questions/39427/do-we-actually-have-the-technology-for-a-permanent-moon-outpost

The technical problem has been solved. Let's talk about the material problem

As the saying goes, it is difficult for a skillful woman to make a meal without rice, and construction cannot do without building materials, so the problem comes: how can building materials be solved

The gravity on the moon is one sixth of that on the earth, and the structural mechanics of building materials is different from that on the earth. Moreover, the temperature difference on the moon is great, and the extreme change of temperature will also affect the building strength; What's more, there are more frequent earthquakes on the moon than on the earth, which makes the construction of the base more demanding on building materials

Can raw materials for

base construction be obtained locally on the moon

Ramon pamis, a professor at the Polytechnic University of Cartagena (Murcia), explained: to make polymers for the construction of lunar bases, in-situ resources can be used, using the soil on the lunar surface (loose material from the lunar surface) and water in ice in some areas,

The

water is a very valuable resource on the surface of the moon, and it is not easy to obtain. The water on the moon mainly exists in the form of gaseous water and ice water. From the known data, it is still unknown how much water ice there is

Even if there is enough water ice, it is difficult to heat water ice into water from the deep pit of - 240 ℃

in 2014, some scholars proposed a 3D printing process using Sorel cement (Sorel cement, also known as glass magnesium plate, is a cementitious material formed by combining magnesium chloride, magnesium oxide and water, which has the advantages of fast setting, high strength, strong adhesion, low density, low pH value and strong plasticity) to construct on the lunar surface. Unfortunately, this method requires a lot of consumables (chemicals and water) to produce the adhesive

Is it possible to transport water from the earth

Let's calculate the cost first. The cost of transporting about 0.45 kg from earth to space is about US $10000, or more than 70000 yuan. If you want to transport water to build a base, the cost is unimaginable

So the researchers thought of using raw materials provided by astronauts, such as urine

Recently, European researchers found that urea in urine can be used as a plasticizer in structural concrete. Scientists from Norway, Spain, the Netherlands and Italy have carried out several experiments with ESA to verify the potential of urea as a plasticizer. It is found that urea can be incorporated into concrete to soften the initial mixture and make it softer before hardening

The

plasticizer is a kind of chemical substance which can reduce the glass transition temperature and melting temperature of polymer compound, improve the brittleness of adhesive layer and improve the melt fluidity. Plasticizers are added to the polymer and distributed among the macromolecular chains, which can reduce the intermolecular force, reduce the viscosity and enhance the flexibility of the polymer

The higher the water content of general concrete, the better its fluidity and processability. However, when the concrete has enough moisture, the strength of the concrete is inversely proportional to the moisture content. Therefore, if the concrete has high strength, the water content of the concrete should not be too much, and the plasticizer can reduce its water content (therefore called water reducing agent) without affecting the workability of the concrete, and improve the strength of the concrete

The plasticizers of

mainly include aliphatic dibasic acid esters, phthalic acid esters (including phthalic acid esters, terephthalic acid esters), phenylpolyacid esters, benzoic acid esters, polyol esters, chlorinated hydrocarbons, epoxides, citric acid esters, polyesters, etc. At present, thousands of plasticizers have been developed and produced in the world, among which 300-400 are widely used, and about 100-110 are produced in China. The plasticizers used in building concrete are mainly polycarboxylate compounds

at Osford University College (Norway), researchers used ESA developed materials similar to lunar rocks, added urea and various plasticizers, and then used 3D printers to make various slurry cylinders, printed out various infrastructure samples, and compared their effects. The experimental results show that the shape of the samples doped with urea is almost stable. Even after heating to 80 ℃ Isn't it amazing to use urine to build a lunar base

After all, under the condition of limited resources, all kinds of available resources are precious resources. In the future, the construction of China's lunar base also needs in-situ resource utilization. At that time, all kinds of black technology will have to show 72 kinds of martial arts. Let's wait and see

References:

Shima Pilehvar et al, Utilization of urea as an accessible superplasticizer on the moon for lunar geopolymer mixtures, Journal of Cleaner Production (2019). DOI: 10.1016/j.jclepro.2019.119177

The

article only represents the author's point of view, not the position of China's science Expo

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