By 2028, NASA intends to land the “first woman and first color of color” on the moon as part of Artemis III mission. This is the first time that people have run there since the Astronauts of Apollo on the moon surface in 1972. Together with international and commercial partners, NASA hopes that Artemis will enable a “persistent program of the moon study and development”, which could include long -term facilities and habitats on the moon. In view of the costs for the start of heavy payloads, it is impractical to send all devices and materials to the moon.
This means that structures on the moon have to be produced with local resources, a process that is referred to as in-situ resource utilization (ISRU). On the moon, this process uses the progress in additive manufacturing (AM) or 3D printing to transform the moon regoliths into building materials. Unfortunately, technical problems mean that most 3D printing techniques on the moon surface are not possible. In a recently carried out study, a team of researchers headed by the University of Arkansas proposed an alternative method in which the light -based sintering is used for the production of moon stones instead of printing entire structures.
The research team is headed by Wan Shou, an assistant professor at the department for mechanical engineering at the University of Arkansas. It is accompanied by Cole McCallum, Youwen Liang and Nahid Tushar, an honorary college scholarship holder, research assistant and doctoral student at the University College of Engineering. The team also included researchers from the Ministry of Mechanical Engineering and Aerospace Technology at the University of Houston and the Faculty of Engineering and Natural Sciences at Tampere University.
It is accompanied by Cole McCallum, Youwen Liang and Nahid Tushar, an honorary college scholarship holder, research assistant and doctoral student at the University College of Engineering. At àhe, Cole McCallum, a student of the Bachelor's College, Youwen Liang, doctoral student and Nahid Tushar, becomes a doctor, doctoral student at the University of Engineering.
Concept for a lunar habitat that was designed by the architecture company Foster + Partners. Credit: Esa/Foster + Partner
As you determine in your work, the creation of a permanent (or semi-permanent) basis on the moon has been the subject of research studies and suggestions since the Apollo era. These plans were always impaired by the simple fact that the necessary machines and building materials would require many heavy carrier strength vehicles in order to deliver them at high costs. While the cost of sending payloads in the past decade has dropped significantly, the costs for the start are everything that astronauts need for the construction of a moon complex, especially thanks to the development of reusable rockets by the commercial area sector.
As a result, only Isru is enough to create bases on the moon. Unfortunately, most of the proposed methods for 3D printing structures in the moon environment are not practical, where gravity is significantly lower (16.5% of the earth) and the temperatures extreme. In the southern Pole-Aitken basin of the moon, where NASA and other space agencies plan to build their bases, the temperatures of 54 ° C (130 ° F) in the sunlight ranges to -246 ° C (-410 ° F) range in the shadow regions. This is because most of the methods for the moon require additional supplies, including solvents, polymers or other bonding agents.
Examples are the work of the European Space Agency (ESA) with the architecture company Foster + Partners in order to create a 3D-printed Moonbase concept. As Prof. Shou explained:
There are many of the methods in which a solvent is required for the production of paste or composite materials for extrusion or pressure. These approaches are not feasible because the transport of solvents can be very expensive and the evaporation of solvents can cause many potential problems. Various methods use binders or polymers to implement on. You have similar problems – additional materials, waste treatment. The execution of these machines (ie printer) also requires energy supply.
Sintering technology was also examined as a potential method for 3D printing structures on the moon. This includes the use of various energy sources such as microwaves and lasers that can melt or partially melt regolites. The structure is then printed, layer of layer printed and cools and hardened as soon as it is exposed to air or vacuum of the moon environment. However, these approaches still require complex systems to generate energy.
A 1.5 -ton module that is produced for demonstrating 3D printing techniques using the moon floor. Credit: ESA
“For this reason, our team presents a system in which only moon material is needed for the structures themselves, which eliminates the bottleneck by Binder replenishment missions by the earth,” added Cole, who was the first author on paper that describes its results.
The method that you have proposed and recommended is referred to as light-based sintering, which is based on sunlight, which is focused directly in structures by a series of optics for the sintered mondregoliths. The researchers tested this technology on earth with mondregolith -simulants for the production of glass and mirrors. On the moon, solar energy in sunny regions is consistently present and plentiful, which makes it much more reliable than a power source that needs to be transported. The simplicity of the system makes it very desirable for challenging environments in which repairs will be difficult when something collapses.
However, experiments have shown that the technology still has problems with the production of large, complex structures. For this purpose, the Sou team focused on the production of building components. Said Cole:
While most research on this topic is still based on a mixture of binder and moon floor, the silicon dioxide content of the regolith is so that it can bind to itself at high temperatures when sintering. What we found when trying with larger structures was that there were less uniform and less precision in the parts we created.
For this reason, we found that the best use for our method was to concentrate on the production of a large number of interlocking and reconfiguring bricks for use in large -scale structures. We believe that this “Lego sticks” approach is also advantageous, since the equipment can correspond to the volume restrictions for moon missions, since the total dream is much smaller for the production of each unit.
https://www.youtube.com/watch?v=vwfrcpyavt4
Their work builds on the existing research into sintering technology, which uses various energy sources to melt moon regolites and create building materials. This includes the work of NASA with the Space Architectural company Sinterhab, which suggested to equip the agency's hex-based extra-explorer vehicle (athlete) with microwave sintering technology for the construction of a 3D-printed lunar habitat. However, Said Cole is particularly attractive because it produces reconfiguring bricks.
In particular, the reconfigurability of our brick assemblies is exciting due to the flexibility that we can achieve with the construction process. Since different parts have different material requirements, depending on the problem with which the problem was confronted, we were able to use a variety of techniques. For structures in which a large part is required and in which a high precision is not required, as with radiation protection, our method is of the opinion that our method is promising.
However, before the concept can be recognized, a lot of work still has to be done. As Shou states, further examinations are required to optimize the sinter parameters and material properties. The team also plans to create a prototype and carry out laboratory tests from which you hope that you can refine and scale the technology for use on the moon. You also have to consider how the resulting 3D printer will transport along the moon surface, on which performance options it would rely, and other considerations.
“When it comes to complete implementation, a lot of engineering still has to be carried out,” concluded Cole. “In the future, we have to consider how the sintering process changes in a vacuum or which changes to the build platform are necessary so that parts can be followed, for example. In addition, our device must be able to withstand hard conditions compared to the laboratory environment in which we have worked on challenging problems in this research.
Further reading: Arxiv
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