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Review of possible mineral materials and production techniques for a building material on the moon
Structural Concrete
Abstract
The article provides an overview of findings and production processes of various mineral materials which have been developed and tested worldwide in the past with regard to the establishment of a lunar base. At the beginning, the aim and procedure of constructing a lunar base will be outlined briefly. Subsequently, the lunar environment factors and their influence on a possible construction will be described. Then the advantages and disadvantages of examined materials such as sulfur concrete, cast basalt, lunar concrete or polymer concrete, on the one hand, as well as previously investigated production processes like sintering, geothermite reaction and 3D printing, on the other hand, are presented. One promising method is the Dry-Mix/Steam-Injection method for producing a lunar concrete as a possible material which is based on cement made from lunar resources developed by T. D. Lin.
... An interesting path that does not require cement and water is sulfur concrete. [13,[41][42][43][44] It forms a highstrength and chemical-resistant material due to solidification when it cools below 140°C, thus binding aggregates together. [42] Compared to the mentioned possibilities as construction materials on celestial objects, sulfur concrete combines the advantages of no water needed and high early compressive strength. ...
... [31,32] [51,52] It is found on the Moon as troilite (FeS) in amounts of around 0.3 wt% of the total mass. [41] Sulfur-rich ores are present as veins, and troilite blebs have been found in different Lunar samples. [43,53] Although the concentration in the total material is low, the sulfur can be extracted with 90 % yield by heating at 1000°C, using solar energy as the heat source. ...
... The terrestrial advantages of using sulfur as a binder of concrete are a) the reduction of the carbon CO 2 footprint as no cement is used, [13,[41][42][43][44] b) the low price of sulfur, it being a waste material from the petroleum industry, [93] c) the ability of production at freezing/elevated temperatures with an acceptable freeze-thawing resistance [48], d) the quick hardening, e) the excellent bond with, for example, porphyry aggregates, f) the high mechanical properties and high fatigue resistance [42], g) the resistance to acids and salts [42,48,63,94,95], h) the compatibility with ecosystems [48], and i) the protection against ionizing radiation [96,97]. These all support the potential of sulfur concrete in relation to its application on celestial objects. ...
The need to build a long-term or even permanent base is now a significant concern with the development of the exploration of extraterrestrial celestial bodies. Sulfur concrete was first proposed as a new building material in the 20th century. Recently, sulfur concrete has attracted much interest, as sulfur is considered one of the most accessible resources on the Moon and Mars, thanks to the in-situ resource utilization methodology. In addition, sulfur concrete is one of the most promising building materials for improving terrestrial sustainability or extraterrestrial exploration. So far, reviews have only focused on developing sulfur concrete and extraterrestrial building materials. This review paper summarizes the history of sulfur concrete development and different modified sulfur concretes. Previous research on extraterrestrial building materials is also reviewed. The unique advantage of sulfur concrete as an extraterrestrial material is justified, as no water is used during mixing. Lunar and Martian soil simulants are also examined as possible aggregate types. Finally, further improvements are proposed to broaden the application of sulfur concrete and the corresponding treatments. The possibility of recyclability and circularity is discussed from a sustainable development point of view. This review article provides readers with a detailed overview of sulfur concrete and its history, why it is more promising and accessible as an (extra)terrestrial building material, the challenges of its future application, and corresponding treatments to overcome the obstacles.
... Regolith melting and forming involve reshaping lunar or Martian soil at high temperatures, directly utilizing in-situ resources to create strong and durable structures. Laser sintering and microwave sintering technologies employ focused laser beams and microwave radiation, respectively, to fuse regolith particles into dense, robust structures, enabling the construction of complex and resilient infrastructures on the lunar or Martian surface [4,5]. ...
... In response to this challenge, Wilhelm et al. [27] introduced the dry-mix/steam-injection (DMSI) method, which reduced water usage while maintaining compressive strength through the application of high temperature and steam pressure. They also noted the importance of controlling the cooling process during manufacturing to mitigate cracking, emphasizing the significance of temperature control [4]. Moreover, the study by Zuo et al. [28] revealed that sulfur concrete exhibits comparable curing strength in both vacuum and standard atmospheric environments. ...
... The Moon, being the closest celestial body to Earth, unquestionably serves as the primary destination for human space exploration. The unique environment and rich mineral resources on the Moon are strategically significant for space exploration [1][2][3]. Therefore, the construction of a lunar base, as a scientific research facility or supply station for deep space exploration, on the surface of the Moon is necessary [4,5]. Dispatching resources through Earth-Moon round-trip transportation is uneconomical because it entails significant depletion of Earth's resources. ...
... A significant mass loss, accompanied by a substantial evolution of CO 2 , is observed in the temperature range of 500 • C to 600 • C. This mass loss is attributed to the decomposition of a non-lunar trace carbonate, such as CaCO 3 . Notably different from the vacuum sintering investigated in that study, air sintering involving oxygen effectively increases the heat energy required for the fusion process of amorphous phases and expedites their molten state evaporation [45,46]. ...
Lunar regolith is the preferred material for lunar base construction using in situ resource utilization technology. The TiO2 variations in lunar regolith collected from different locations significantly impact its suitability as a construction material. Therefore, it is crucial to investigate the effects of TiO2 on the properties of lunar regolith. This study aims to evaluate the influence of TiO2 content and sintering temperature on phase transformation, microstructure, and macroscopic properties (e.g., the shrinkage rate, mechanical properties, and relative density) of lunar regolith simulant samples (CUG-1A). The flexural strength and relative density of the sample with a TiO2 content of 6 wt% sintered at 1100 °C reached 136.66 ± 4.92 MPa and 91.06%, which were 65% and 12.28% higher than those of the sample not doped with TiO2, respectively. The experiment demonstrated that the doped TiO2 not only reacted with Fe to form pseudobrookite (Fe2TiO5) but also effectively reduced the viscosity of the glass phase during heat treatment. As the sintering temperature increased, the particles underwent a gradual melting process, leading to a higher proportion of the liquid phase. The higher liquid-phase content had a positive impact on the diffusion of mass transfer, causing the voids and gaps between particles to shrink. This shrinkage resulted in greater density and, ultimately, improved the mechanical properties of the material.
... Using local materials from lunar resources to realize in situ construction is a feasible method. The entire Moon surface was covered with lunar regolith [78], and the mineral composition is similar to that of basalt ore distributed on Earth's surface [ [79][80][81][82][83]. Because of the extreme lunar environment, such as high vacuum and low gravity, the common methods for Earth construction are not suitable for the Moon. ...
... Up to now, it is still not very realistic to build large structures using only lunar soil. In addition, the common 3D printing method on the Moon is usually limited by shaping processes and material characteristics, and it cannot be fully applied on the lunar surface with insufficient resources [79,113]. Therefore, the extrusion printing method of lunar regolith inks has attracted extensive attention from researchers due to its wide range of applications. ...
Along with the rapid development of space technology, extraterrestrial exploration has gradually tended to further-distanced and longer-termed planet exploration. As the first step of an attempt for humans to build a perpetual planet base, building a lunar base by in situ resource utilization (ISRU) will drastically reduce the reliance of supplies from Earth. Lunar resources including mineral resources, water/ice resources, volatiles, and solar energy will contribute to the establishment of a lunar base for long-term life support and scientific exploration missions, although we must consider the challenges from high vacuum, low gravity, extreme temperature conditions, etc. This article provides a comprehensive review of the past developing processes of ISRU and the latest progress of several ISRU technologies, including in situ water access, in situ oxygen production, in situ construction and manufacture, in situ energy utilization, and in situ life support and plant cultivation on the Moon. Despite being able to provide some material and energy supplies for lunar base construction and scientific exploration, the ISRU technologies need continuous validation and upgrade to satisfy the higher requirements from further lunar exploration missions. Ultimately, a 3-step development plan for lunar ISRU technologies in the next decade is proposed, which consists of providing technological solutions, conducting technical verification on payloads, and carrying out in situ experiments, with the ultimate aim of establishing a permanent lunar station and carrying out long-term lunar surface scientific activities. The overview of ISRU techniques and our suggestions will provide potential guidance for China’s future lunar exploration missions.
... Furthermore, many new materials are proposed for use in space construction, including sintered material, polymer-bound regolith, products of geo-thermite reactions, microbial-induced calcite precipitation, and regolith-based magnesium oxychloride. The synthesis of these binders needs considerations regarding energy consumption and raw material availability [1,8,[20][21][22][23]. This study will not attempt to survey all possible material concepts but will scrutinize those that are currently at an advanced stage of development. ...
... However, more research needs to be conducted on this cement. Furthermore, the two most significant barriers to using this method for space habitat construction are the energy-intensive extraction and the large amount of metal needed for the powder [22]. ...
Mars is the most accessible planet in the solar system for habitation and could serve as a base for exploring more distant planets. Space agencies and scientists worldwide continue exploring Mars to gain more geologic and atmospheric information in preparation for constructing space habitats. The harsh planetary conditions of Mars require the development of new or modified methods for building infrastructure and formulating binders. Each type of concrete has advantages and disadvantages, and we need to find the best binder for use in construction on Mars.
In this study, eight construction materials, including Ordinary Portland cement (OPC), sulfur concrete, geopolymer, sintered material, polymer-bound regolith, products of geo-thermite reactions, regolith-based magnesium oxychloride, and microbial-induced calcite precipitation, are reviewed according to 14 criteria. The criteria are availability, shipping, water requirement, technical working conditions, curing time, temperature, total required energy, strength, durability, cosmic radiation shield (density and hydrogen content), additives needed, sustainability, safety, and recyclability. We applied the Fuzzy Analytic Hierarchy Process (AHP) approach to assign a weighting to each criterion. Finally, we used three multi-criteria decision-making (MCDM) methods to determine the most suitable mortar for construction under the harsh conditions on Mars.
The results show that if the general conditions of Mars are considered uniform such as different temperatures and geologies dependent on location, geopolymer concrete is the best material for construction based on Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), and Weighted Aggregates Sum Product Assessment (WASPAS) methods, and sintered material concrete and sulfur concrete are equally ranked second. Correspondingly, five concretes of Portland cement, products of geo-thermite reactions, regolith-based magnesium oxychloride, polymer-bound regolith, and microbial-induced calcite precipitation are the most efficient construction materials, respectively. In addition, using the Fuzzy AHP method, the criteria of shipping and sustainability have the highest and lowest weighting, respectively, in the decision-making process. The use of MCDM methods and inductive analysis provides a scientific approach that enables the comparison of the potential of several space concrete materials for better decision making in future research and construction within the next 10–20 years.
... In situ resource utilization (ISRU), which can make the exploration of the Moon much more sustainable by dramatically reducing the cost, has become a focal point of research targeted at developing technologies in support of long-term on-site exploration [7][8][9]. The lunar regolith, covering the entire surface of the Moon and mainly comprising aluminosilicate-based mineral and glass, is the main resource available as a straightforward raw material for construction [7,10]. In addition, the lunar regolith also has the potential to be used as the raw material for the manufacturing of functional components, such as thermal energy storage blocks, which may extricate missions from being dependent on chemical batteries [8,9]. ...
The mechanical and thermal properties of the fabricated structures composed of lunar regolith are of great interest due to the urgent demand for in situ construction and manufacturing on the Moon for sustainable human habitation. This work demonstrates the great enhancement of the mechanical and thermal properties of CUG-1A lunar regolith simulant samples using spark plasma sintering (SPS). The morphology, chemical composition, structure, mechanical and thermal properties of the molten and SPSed samples were investigated. The sintering temperature significantly influenced the microstructure and macroscopic properties of these samples. The highest density (~99.7%), highest thermal conductivity (2.65 W·m⁻¹·K⁻¹ at 1073 K), and the best mechanical properties (compressive strength: 370.2 MPa, flexural strength: 81.4 MPa) were observed for the SPSed sample sintered at 1273 K. The enhanced thermal and mechanical properties of these lunar regolith simulant samples are attributed to the compact structure and the tight bonding between particles via homogenous glass.
... 16,17 Currently, more studied lunar concrete has focused on sulfurbased concrete, polymer concrete, geopolymer concrete, and ordinary aluminosilicate concrete. 18 Sulfur-based concrete replaces cement with sulfur as the binder. Sulfur is thermoplastic. ...
The lunar regolith can be utilized as raw materials for constructing lunar bases through the fabrication of lunar cement. However, the low CaO content in lunar regolith presents a challenge for producing silicate cement. This study explores enriching CaO in NEU-1 lunar soil simulant by calciothermic reduction. Non-isothermal differential scanning calorimetry analysis indicated that calcium reacted with Fe2O3, SiO2, and Al2O3 at approximately 808°C, 816°C, and 826°C, respectively. The reaction ratios were 1.1, 1.6, and 0.8, with apparent activation energies of 941.6 kJ/mol, 965.17 kJ/mol, and 547.28 kJ/mol. The products obtained from the calciothermic reduction of lunar soil simulant were CaO, Ca2Si, and AlFe, as analyzed by X-ray diffraction. Increasing the temperature was found to be beneficial to the reaction process, and a suitable reaction temperature of 850°C was determined. X-ray photoelectron spectroscopy analysis showed that the reduction percentages of SiO2 and Al2O3 were 93.01% and 91.04%, respectively, at 850°C for 30 min. The CaO content in the product obtained by calciothermic reduction was 50.65%, which could be further increased to 81.16% after crude purification, and the CaO yield was 82.57%. These results demonstrated that the process has a significant CaO enrichment effect.
... Therefore, in order to stand out in the fiercely competitive market, occupy a dominant position, and achieve the important strategic goal of long-term and sustainable development, the modern construction industry must reasonably select decorative materials and continuously optimize the construction process. Only in this way can it provide adequate protection for the further development of the construction industry [13][14][15][16]. ...
Firstly, on the basis of the multi-objective planning model, we determine the objective function of building energy consumption, the objective function of material cost and the objective function of uncomfortable time percentage. We propose to use a multi-objective genetic algorithm to obtain the Pareto frontier solution for the decision variables of the model by selecting them. The target constraints are determined based on the construction of the building decoration project, and the model of remodeling material cost-schedule-carbon emission’ is constructed. The discrete simulation model of the decoration project is constructed based on the design parameters of the enclosure structure and air conditioning. Considering the structural rigor of the research and analysis, it is necessary to set and explain the parameters of the simulation model, and the materials of the decoration project are studied and analyzed. The results show that on the engineering case analysis, the value of building energy consumption, building cost and the value of uncomfortable time percentage have increased by 23%-45% compared with the value before optimization. In the simulation model, the optimized construction solution’s carbon emission, cost, and duration were reduced by 6.22%, 10.65%, and 45.48%, respectively, compared to the original solution. This study illustrates the aesthetic performance and functional performance on the basis of the process of new materials, which is a guiding reference value for the application of new materials in architectural decoration engineering.
... Lunar sulfur concrete (Toutanji et al., 2012) is widely studied because of its high compressive strength and no usage of water. However, sulfur is lacked on the moon (< 1% by mass) and easy to be sublimed, indicating low durability (Wilhelm & Curbach, 2014). Considering Si is the second abundant element on the moon, moon sand can offer an alternative solution. ...
... According to current research, the prohibitive cost of transporting source materials and the substantial payload sent from Earth have significantly restricted the development of lunar construction. Therefore, in-situ resource utilization (ISRU) technology provides a promising solution for lunar base construction [14,15]. Harvesting water and oxygen, growing food, and preparing construction materials are a few current ISRU research concerns [16,17]. ...
... There was a boom in research into lunar construction materials in the 1990 s, and a variety of preparation techniques have been proposed in previous studies, such as dry-mixed concrete [5][6][7][8], sintered material [9][10], polymer concrete [11][12][13], geopolymer concrete [14], and sulfur concrete [15][16][17][18]. According to a comprehensive analysis of lunar construction material systems, each method has its advantages and disadvantages [19]. Therefore, the most suitable technology for preparing lunar construction materials in situ remains undecided, nor can it be verified at the current time. ...
Lunar landing pad is an important infrastructure on the lunar surface and is used to improve landing safety and mitigate dust problems caused by launch and landing. It will be subjected to the dynamic mechanical loading from the footpads of the spacecraft and the retrorocket plume loading. Only the former was considered in this study, and the latter will be explored in future studies. Prefabricated module assembly method is one of the most feasible construction methods. The assembly pattern, size, and thickness of the prefabricated modules are important factors that affect the structural performance of the lunar landing pad. In this study, three forms of mechanical interlocking were identified for an assembled lunar landing pad (ALLP) according to the interlocking form. In addition, a simple shape was designed for each form. Interlocking concrete blocks were fabricated, and a plate loading test (PLT) was conducted to evaluate the structural performance of the assembled concrete block pavement (ACBP). By comparing the numerical and experimental results, corresponding finite element (FE) models of the plate loading tests were developed and validated. Finally, an FE model to evaluate the structural performance of the ALLP based on the validated ACBP FE model was developed. The effects of the size and thickness of the interlocking modules and load position on the structural performance of the ALLP were further studied. The results indicated that the thickness of the modules had a greater influence on the structural performance than the load position and size of the modules. This study is expected to provide a reference for the design and construction of lunar landing pads.
... In terms of materials and technology of on-orbit manufacturing, European and American countries have carried out a series of tasks: "SpiderFab Project" [3][4] , "Architect Project" [5] , "OSAM" [6][7] , "Space Factory Plan" [8] , "ISRU" [9] , "NOM4D" [10] , and completed the ground environmental test verification of typical structural members such as boom, antenna adapter arm, truss, lunar base dome structure [11][12][13] . The thermoplastic composite systems such as PEEK, PEI, ABS, ULTEM9085 plastic, carbon fiber reinforced composite, UTEP composite, etc., which are suitable for on-orbit manufacturing have been established [14] . ...
On-orbit manufacturing is affected by space microgravity, high vacuum, large temperature variation, strong radiation and other environmental factors, which also puts forward new requirements for materials and process methods suitable for on-orbit manufacturing. This paper summarizes the current research status of different scholars on materials and technologies for on-orbit manufacturing. The main application scenarios and requirements of on-orbit manufacturing are analysed. The technical capability requirements under different application requirements are analysed. Then according to the material source, material use and manufacturability, the material system for in-orbit manufacturing is established. According to different technical requirements, the manufacturing technology system of on-orbit manufacturing is established. From the point of view of materials and technology, the key technical directions that should be broken through in on-orbit manufacturing are put forward. It can provide reference for the subsequent research on materials and process technology of on-orbit manufacturing.
... AI and ML can optimize planning expeditions for scientific purposes, identifying sites that maximize scientific value and minimize risk to scientists such as those from radiation, regolith, extreme temperatures, and surface impacts (Benaroya, Bernold and Chua, 2018; Grün, Horanyi and Sternovsky, 2011;Wilhelm and Curbach, 2014). Using existing lunar data, AI and ML can optimize locations for conducting lunar experiments in seismology, geology, astronomy, and other fields. ...
This study undertakes an interdisciplinary investigation into the application of artificial intelligence and machine learning to optimize the establishment of a lunar outpost. It focuses on seven core disciplines: space applications; engineering; management and business; human performance; science; humanities; and policy, ethics, and law. A review of existing literature for each discipline informed the selection of target specifications to optimize. These specifications were evaluated, and outpost location optimization was selected as the primary subject of the study. Five selected specifications were identified as needing to be satisfied: maximizing solar exposure; ease of terrain access; proximity to sites of scientific interest; minimizing environmental impacts on crew health; and access to resources. The report identifies functional requirements that need to be satisfied by an artificial intelligence and machine learning application and develops a final proposed system. It then presents a prototype computational model for optimizing outpost location for terrain access. A discussion of the ethical, policy and legal implications of the proposed system follows, and future extensions and improvements of the system are recommended, including applications for future off-Earth missions and the commercialization of AI as a service.
... Therefore, researchers have focused on In-Situ Resource Utilization (ISRU) technologies. Lunar soil (i.e., regolith) is envisioned to be used in different forms as a building material [18]. Due to limited availability of lunar regolith samples, most of the comprehensive studies are carried out using lunar regolith simulants [19]. ...
This paper presents the methodology to determine the temperature profile at the surface and through the wall
thickness of a monolithic hemispherical dome-shaped habitat structure built on the lunar surface. The three dimensional
thermodynamic equation of heat diffusion is used to determine the temperature profiles using the explicit finite difference scheme. The direct solar radiation and lunar albedo are taken as the heat sources on the habitat structure whereas non-black body radiation and habitat albedo were taken as heat sinks. In this study,
all the applicable modes of heat transfer – radiation in the external wall surface, convection in the internal wall surface (interior habitat will have air for human missions), and conduction in the structural wall body – have been considered. This temperature analysis study also takes into consideration of the self-shadowing effect of the habitat structure itself. The temperatures at the surface and through the wall thickness of the monolithic dome habitat structure were determined for the habitat structure made of sintered lunar regolith simulant, and for the purpose of comparison, regular terrestrial concrete, for three complete lunar day-and-night cycles. While the maximum temperature of around 390 K was observed at the apex of the sintered lunar regolith simulant dome during the lunar noon, the minimum temperature observed was around 213.5 K during the night time on the external surface of the habitat wall. The corresponding results for the lunar habitat structure made of terrestrial concrete were 364 K and 222.5 K, respectively. At the inner surface of the 40 cm thick habitat structure (in contact with interior habitat environment), the temperature fluctuation (difference between maximum and minimum temperatures) can be up to 30 K for each material type. The results from this study should help to determine the structural stresses and deflections caused by such lunar environment temperature fluctuations and
the heat regulation for habitability in the future habitat structure on the Moon. Moreover, the methodology presented in this study should be applicable to conduct parametric studies to evaluate the effect of different parameters on the structural habitat temperature results.
(https://doi.org/10.1016/j.actaastro.2022.12.040 )
... Bazalt lifleri çoğunlukla patlamaya dayanıklı yapılarda tercih edilebilir, çünkü daha fazla sertliğe sahip lifi, daha az sapma ile hasara karşı daha fazla dirence ve kopmaya karşı daha yüksek dirence sahip olduğu belirlenmiştir. Basınç altında bazalt bileşimi yüksek mukavemet sağlayabilmektedir (Wilhelm and Curbach 2014).Çok sayıda araştırmacı, statik yükleme koşulları altında bazalt lifli betonun performansını incelemişlerdir. Bazalt fiberin temel mekanik özelliklerini belirleyebilmek için, basınç, çekme ve eğilme altında incelemişlerdir (Ayub, Shafiq, and Nuruddin 2014;Borhan 2013;Iyer, Kenno, and Das 2015;Kaijian and Deng 2010;Yang et al. 2021;Yang and Lian 2011;Zhou et al. 2020). ...
ZET Bazalt fiber, bazalt kayalarından elde edilerek çeşitli işlemlerden geçirilip epoksi reçine ile bağlayıcılığı sağlanarak elde edilmektedir. Bazalt fiberin nervürlü donatı çubuğu haline getirilip beton ile kullanılabilirliği araştırılmıştır. Beton ile aderans uyumu, çekme ve eğilmeye karşı davranışları incelenmiştir. Bazalt fiberin üretiminin ve epoksi reçinesinin özelliği farklı sonuçlar elde edilmesine neden olmuştur. Üretim sürecinin malzemenin kimyasal içeriğinden dolayı farklılığına sebebiyet vermiştir. ABSTRACT Basalt fiber is obtained from basalt rocks, subjected to various processes and bonded with epoxy resin. The usability of basalt fiber with concrete was investigated by turning it into a deformed reinforcement. Adherence compatibility with concrete, behavior against tension and bending were investigated. The characteristics of basalt fiber production and epoxy resin have resulted in different results. The production process has caused differences due to the chemical content of the material.
... Basaltic regolith is readily available on the Moon surface [44], [45]. This basaltic soil can be used to produce thin filaments of basalt fiber [46], [47]. The fibers can have non-corrosive properties and highmechanical strength. ...
This study investigates the mechanical properties of a novel composite for a lunar space habitat. The research aims to identify high-mechanical strength materials for a robotically fabricated habitat with in-situ resources. Several basalt fiber types and cementitious matrices were investigated for building a fiber-reinforced composite. The effect of the basalt fiber type-chopped, spooled, and long; and fiber percentage-1 wt. %, 5 wt. %, and 10 wt. %; was investigated. The samples were initially exposed to a maximum lunar environmental temperature of 117°C and a medium vacuum of 0.01 atm for 24 hours. Then, these samples were tested after curing for flexural and compressive strengths until failure and cracking occurred. The 10% chopped basalt fiber and the 5% long basalt fiber composite proved the most promising combination for a high-mechanical strength composite. These composites demonstrated an improved compressive and flexural strength for the cement slurry. Moreover, this study enables the robotic fabrication potential of a mechanically resilient lunar habitat.
... However, the existing lunar atmosphere is very thin, mainly composed of neon, hydrogen, helium, and argon, so the lunar atmosphere can be viewed as a vacuum environment. Because the lunar surface is close to a vacuum environment, there are almost no obstacles when meteorites and micrometeorites with mass less than 10 -2 g hit the lunar surface at a speed of 20-70 km/s [15], which produce dense craters and meteor craters on the Moon. ...
Concrete is an ideal material for human beings to build bases on the Moon and Mars, and it is an important material basis for human beings to explore outer planets. In this paper, the history of space exploration is briefly introduced. Based on the resources and environmental conditions on Moon and Mars, the preparation methods and properties of different lunar and Martian concretes were analyzed and compared, e.g., aluminate concrete, sulfur concrete, magnesia silica concrete, polymer concrete, and geopolymer concrete. Based on the existing research findings, further research directions are put forward for the existing limitations and issues in current research.
... As the astral body closest to the earth, the Moon is rich in mineral resources and has a unique space environment, prompting increasing exploration by major aerospace agencies [1][2][3][4]. To implement scientific research, resource exploitation, and human settlement on the Moon, a sustainable and stable lunar base must first be established [5,6]. ...
Three-dimensional (3D) printing is one of the most promising techniques for on-site manufacturing and is expected to become a key technology for the construction and maintenance of lunar bases. In this study, powder surface modification was integrated with digital light process (DLP)-based 3D printing to improve the mechanical properties of 3D printed lunar regolith simulant (CUG-1A) structures. A silane coupling agent (KH570) was utilised to modify the CUG-1A powder, and the underlying surface modification mechanism was elucidated. In addition, the effects of the silane coupling agent on the rheological properties, wettability, cure depth and dispersity of the slurries were investigated. It was revealed that the introduction of the silane coupling agent improved the wettability between the CUG-1A powder and photocurable resin, which effectively decreased the slurry viscosity. In addition, powder surface modification enhanced the homogeneity of CUG-1A particle distribution, which is beneficial for obtaining a uniformly distributed liquid phase during the sintering process, thus promoting the sintering densification of the printed sample. The relative density and flexural strength of the CUG-1A sample prepared by the modified powder sintered at 1100 °C reached 86.47% and 91.13±5.50 MPa, being 6.5% and 22.5% higher than the values of sample prepared by the unmodified powder, respectively. Finally, complex shaped lunar regolith simulant structures were successfully fabricated via DLP-stereolithography integrated with powder surface modification, which indicating powder surface modification is an effective way to fabricate 3D printed lunar regolith simulant components with high density and mechanical strength.
... The prohibitive cost of transporting raw materials from the Earth to either the Moon or Mars is the driving factor for pursuing in-situ resource utilization (ISRU). The lack of oxygen, extreme thermal cycles, solar and cosmic radiation are significant challenges when attempting to construct a base in these harsh environments [1][2][3][4]. Such bases, would most likely be constructed using a variety of materials, architectures and shapes as depicted in Figure 1. ...
Cylindrical specimens of Martian and Lunar regolith simulants were molded using a salt water binder and sintered at various temperatures for comparing microstructure, mechanical properties and shrinkage. Material microstructure are reported using optical microscope and material testing is done using an MTS universal testing machine. The experimental protocol was executed twice, once using Mars global simulant (MGS-1), and once using Lunar mare simulant (LMS-1). The specimens were fabricated via an injection molding method, designed to replicate typical masonary units as well as the green stage of Binder Jet Technique, an important additive manufacturing (AM) technique. Results show that for both the Martian and Lunar regolith that the optimal sintering temperature was somewhere between 1100 C and 1200 C. The compressive strength for both the Martian and Lunar masonary samples, that received optimal sintering conditions, was determined to be sufficient for construction of extraterrestrial structures. The work demonstrates that both the Martian and Lunar regolith show potential to be used as extra terrestrial masonary and as parent material for extra terrestrial BJT additive manufacturing processes.
... The primary challenge of building habitats on Mars is developing an economical and suitable construction material. Some building materials that are made by in-situ recourses utilization (ISRU) have been proposed, e.g., concrete based on the binder of sorel cement, sulfur, or ceramics [2], [3]. However, none of the concrete systems can be easily used there especially at the initial stage of landing mars missions, not only because of the high cost of transporting a large amount of raw material and heavy facilities but also the special atmospheric conditions there. ...
... NO the European Space Agency (ESA) announced plans to restart manned missions for the exploration of outer space [2][3][4][5][6]. For feasible and sustainable space exploration, these habitats need to be built from available in situ resources on moon/Mars [7][8][9][10][11]. Within space lexicon, the term in situ resource utilization (ISRU) refers to any process that encourages processing of local resources found during exploration of extra terrestrial habitats in order to reduce dependency on materials chaperoned from Earth. ...
We demonstrate that Microbial Induced Calcite Precipitation (MICP) can be utilized for creation of consolidates of Martian Simulant Soil (MSS) and Lunar Simulant Soil (LSS) in the form of a ‘brick’. A urease producer bacterium, Sporosarcina pasteurii, was used to induce the MICP process for the both simulant soils. An admixture of guar gum as an organic polymer and NiCl2, as bio- catalyst to enhance urease activity, was introduced to increase the compressive strength of the biologically grown bricks. A casting method was utilized for a slurry consisting of the appropriate simulant soil and microbe; the slurry over a few days consolidated in the form of a ‘brick’ of the desired shape. In case of MSS, maximum strength of 3.3 MPa was obtained with 10mM NiCl2 and 1% guar gum supplementation whereas in case of LSS maximum strength of 5.65 Mpa was obtained with 1% guar gum supplementation and 10mM NiCl2. MICP mediated consolidation of the simulant soil was confirmed with field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and thermogravimetry (TG). Our work demonstrates a biological approach with an explicit casting method towards manufacturing of consolidated structures using extra-terrestrial regolith simulant; this is a promising route for in situ development of structural elements on the extra-terrestrial habitats.
... There was a boom in research into lunar construction materials in the 1990 s, and a variety of preparation techniques have been proposed in previous studies, such as dry-mixed concrete [5][6][7][8], sintered material [9][10], polymer concrete [11][12][13], geopolymer concrete [14], and sulfur concrete [15][16][17][18]. According to a comprehensive analysis of lunar construction material systems, each method has its advantages and disadvantages [19]. Therefore, the most suitable technology for preparing lunar construction materials in situ remains undecided, nor can it be verified at the current time. ...
Sintering is a feasible method for the in situ manufacturing of lunar construction materials with high utilization rates and good service durability. To investigate a feasible in situ sintering method for lunar construction materials, the HUST-1 lunar regolith simulant (LRS) was used as the only raw material in this study, and we compared the apparent state and physicomechanical properties of samples at different calcination temperatures in atmospheric and vacuum environments and explored the influence of the calcining environment and temperature on the mineral composition and morphology. The results indicated that the appropriate sintering temperature range of LRS in an atmospheric environment was 1050–1100 ℃, whereas under a vacuum environment it was 1000–1050 ℃. The main minerals of the vacuum-sintered HUST-1 LRS were consistent with the raw material below 1050 ℃, and the compaction of the microstructure improved with increasing sintering temperature. Finally, the influence of rough forming and sintering pressure in a vacuum environment was investigated. Starting with a powdery rough cylindrical body pre-compacted under 20 kN and sintered for 2 h at 1050 ℃ with 25 kPa vertical pressure resulted in an apparent density of 2768.56 kg/m³, with 89.83% compactness and 58.45–67.68 MPa compressive strength.
... Numerous strategies have been considered for extraterrestrial construction (Happel, 1993;Wilhelm and Curbach, 2014). These include traditional OPC-based concrete with lunar regolith as aggregate (Lin et al., 1992;Neves et al., 2020), solar-sintered regolith (Fateri et al., 2019;Imhof et al., 2017;Meurisse et al., 2018), sulfur cement (Khoshnevis et al., 2016;Toutanji et al., 2012;Wan et al., 2016), Sorel cement (Cesaretti et al., 2014;Ordonez et al., 2017;Werkheiser et al., 2015), phosphoric-acid binder cements (Buchner et al., 2018), epoxy/polymer-based cements (Naser, 2019;Naser and Chehab, 2020;Su et al., 2019), and alkali-activated regolith or 'geopolymer'-type binders (Alexiadis et al., 2017;Davis et al., 2017;Montes et al., 2015;Pilehvar et al., 2020;Zhou et al., 2020). ...
Future human space exploration and habitation on the lunar and Martian surfaces necessitates in-situ resource utilization (ISRU) for the development of construction materials tailored for infrastructure and environmental protection. Here we explore the use of lunar and Martian regoliths to create construction materials with properties suitable for such structures as landing pads. Alkali activation of a spectrum of lunar and Martian regolith simulants generates geopolymer binders under ambient and vacuum curing conditions as well as exposure to extreme high and low temperatures (600 and -80 °C). Compressive strength is reduced for binders prepared from each simulant after curing under vacuum and exposure to sub-zero temperatures. In lunar simulant binders, the compressive strength is increased after heating to 600 °C, but the opposite effect is observed in the Martian simulant binder. Amorphous aluminosilicate content and percentage of small particles in the simulants are hypothesized to have a positive impact on compressive strength under ambient curing. Iron and magnesium content may be responsible for decreased compressive strength of the Martian binder after heating. This study offers a robust framework for comparing performance of different simulants under the same curing protocols and environmental exposures, as well as offering insight as to the effects of vacuum curing, and exposure to high and low temperature environments on cured binder samples. Developing a landing pad by transporting activator to the lunar surface is shown to be conceptually feasible within current payload constraints.
... On the occasion of the 50 th anniversary of manned mission landing on lunar surface, space agencies like the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) announced plans to restart manned missions for the exploration of outer space [2][3][4][5][6]. For feasible and sustainable space exploration, these habitats need to be built from available in situ resources on moon/Mars [7][8][9][10][11]. Within space lexicon, the term in situ resource utilization (ISRU) refers to any process that encourages processing of local resources found during exploration of extra-terrestrial habitats in order to reduce dependency on materials chaperoned from Earth. ...
We demonstrate that Microbial Induced Calcite Precipitation (MICP) can be utilized for creation of consolidates of Martian Simulant Soil (MSS) and Lunar Simulant Soil (LSS) in the form of a 'brick'. A urease producer bacteria, Sporosarcina pasteurii, was used to induce the MICP process for the both simulant soils. An admixture of guar gum as an organic polymer and NiCl2, as bio- catalyst to enhance urease activity, was introduced to increase the compressive strength of the biologically grown bricks. A casting method was utilized for a slurry consisting of the appropriate simulant soil and microbe; the slurry over a few days consolidated in the form of a 'brick' of the desired shape. In case of MSS, maximum strength of 3.3 MPa was obtained with 10mM NiCl2 and 1% guar gum supplementation whereas in case of LSS maximum strength of 5.65 MPa was obtained with 1% guar gum supplementation and 10mM NiCl2. MICP mediated consolidation of the simulant soil was confirmed with field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Our work demonstrates a biological approach with an explicit casting method towards manufacturing of consolidated structures using extra-terrestrial regolith simulant; this is a promising route for in situ development of structural elements on the extra-terrestrial habitats.
... Water appears to have greater abundance in polar regions than sulphur sources suggesting that more traditional Portland-type cements may be more practical. Several other potential lunar cements are possible subject to minor constraints (Wilhelm and Curbach 2014;Ishikawa et al. 1992)lunar pyroxene and plagioclase feldspar are sources of quicklime (CaO) (Mueller et al. 2016). "Lunarcrete" may be formed from melted individual minerals CaO, SiO 2 , and Al 2 O 3 at 3000 K and quenched and mixed with water. ...
We explore the limits of in situ resource utilization (ISRU) on the Moon to maximize living off the land by building lunar bases from in situ material. We adopt the philosophy of indigenous peoples who excelled in sustainability. We are interested in leveraging lunar resources to manufacture an entire lunar base in such a fashion that is fully sustainable and minimizes supplies required from Earth. A range of metals, ceramics and volatiles can be extracted from lunar minerals to support construction of a lunar base that include structure, piping and electrical distribution systems. To 3D print a lunar base, we must 3D print the load-bearing structure, electrical distribution system, water-based heating system, drinking water system, air system and orbital transport system from in situ resources. We also address the manufacture of the interior of the lunar base from local resources. The majority of systems constituting a lunar base can be manufactured from in situ resources.
... A waterless concrete made out of lunar soil simulant cemented together with a polymer was proposed and mechanically measured [31]. A method of manufacturing concrete under vacuum conditions on the moon was proposed and tested by an enhancement of the Dry-Mix/Steam-Injection method (DMSI) [32]. Some researchers have developed methods of lunar regolith sintering into bricks, which is of critical importance for lunar construction. ...
The development of artificial intelligence technology is currently bringing about new opportunities in construction. Machine learning is a major area of interest within the field of artificial intelligence, playing a pivotal role in the process of making construction “smart”. The application of machine learning in construction has the potential to open up an array of opportunities such as site supervision, automatic detection, and intelligent maintenance. However, the implementation of machine learning faces a range of challenges due to the difficulties in acquiring labelled data, especially when applied in a highly complex construction site environment. This paper reviews the history of machine learning development from shallow to deep learning and its applications in construction. The strengths and weaknesses of machine learning technology in construction have been analyzed in order to foresee the future direction of machine learning applications in this sphere. Furthermore, this paper presents suggestions which may benefit researchers in terms of combining specific knowledge domains in construction with machine learning algorithms so as to develop dedicated deep network models for the industry.
... Lunar regolith is seen as a potential material for construction and repairs due to its advantages, such as it being adequately available and non-toxic [4,5]. However, only 400 kg of this material has been gathered from the moon surface during the Apollo missions, which is an insufficient amount of materials for researchers [6]. ...
The key to any presence in space being sustainable is the ability to manufacture the necessary structures and spares in situ and on-demand, in order to avoid the cost, volume, and up-mass constraints that would prohibit a successful launch with everything needed for long-duration and long-distance missions from Earth. In terms of meeting the demand for parts with highly complex geometries and high accuracy, ceramic stereolithography is a revolutionary manufacturing technology, with oxide ceramics being widely studied due to their low levels of light absorption and scattering. This article investigates the feasibility of producing parts from lunar regolith simulant using a vat polymerization (VP) technique called lithography-based ceramic manufacturing (LCM). The conducted analyses include determining the rheological behavior of the suspension and the thermogravimetric characterization of printed green parts, as well as examining the mechanical, structural and microstructural properties through compression tests, computed tomography and SEM of sintered regolith samples.
... For example, in the ISRU construction of roads, landing pads, and shielding structures, regolith can be used as an aggregate or as a sintering powder. Where it is used as an aggregate, it is necessary to use a chemical binder to harden it in a useful form [8,9,[18][19][20][21]. Where it is used as a sintering powder, energy is deposited within the compacted regolith to sinter it into a useful form [1,10,11,14,16,[22][23][24]. ...
The purpose of this study was to deploy a Delphi expert elicitation methodology to better understand the technical and policy challenges facing the development of a sustainable lunar outpost in 2040, including the types and scale of ISRU deployment. We used a three-round Delphi survey with an open first round and specific questions in later rounds using a four-point Likert scale and two ranking exercises to assess energy technologies and inhibiting factors. In order to provide more certainty to our potential participants regarding their input, and boost engagement, the study deployed a three-round approach that was communicated to our potential participants and decided ex-ante. Potential participants were identified from the literature and academic networks as those who had made significant contributions to the fields of; ISRU technologies, space architecture, space-qualified power systems, and space exploration. The study identified around 20 major themes of interest for researchers in the first round and asked participants to rate their agreement with a number of statements about a hypothetical lunar outpost in 2040. From the group responses, we identified three major technical challenges for the development of a lunar outpost in 2040; developing high power energy infrastructure, lander and vehicle ascent capacity, and mission architectures and technical approaches. We also identified three major policy challenges for the development of a lunar outpost in 2040; US and global political instability, possibility of an extended timeframe for the first lunar landing, and political distaste for nuclear energy in space. The group was uncertain about the precise energy mix at the outpost as a result of uncertainty regarding electrical loads, but there was general agreement that solar PV would be a significant contributor. Whether nuclear power sources might play a useful role proved to be very uncertain, with some participants noting a political distaste for space nuclear power systems. However, the proposition gained two votes in each ranking position, suggesting it has a flat distribution including both supporters and detractors.
Dense building components can be fabricated using lunar regolith simulants prepared via microwave sintering. In this study, the microstructure and properties of such simulants containing high (14.72%), medium (6.71%), and low (1.7%) TiO2 contents prepared via microwave sintering at different temperatures (1030°C–1070°C) were studied. The sample sintered at 1060°C with 14.72% TiO2 content exhibited the highest compressive strength of (125.2 ± 22) MPa. This was because high TiO2 content was more conducive to densification due to microwave sintering. The influence of TiO2 content and sintering temperature on the strength of microwave-sintered samples was statistically analyzed, which revealed that sintering temperature was the main influencing factor (F value = 187.3) and TiO2 content was the auxiliary influencing factor (F value = 4.91). Using an enhanced multilayer perceptron model, a continuous surface diagram and prediction model were developed. These were then used to determine the influence of sintering temperature and TiO2 content on the compressive strength as well as to predict compressive strength with comparable accuracy. This study provides insights into microwave sintering of materials for future lunar construction.
Extensive research interest on lunar construction materials, represented by lunar geopolymers, has been driven by the worldwide programs of in-situ lunar exploration. This study comprehensively investigates different combinations between diverse lunar regolith simulants and activators at various curing temperatures, and their effects are revealed by the mechanical properties, microstructure, and composition of resulting lunar geopolymers. This study proposes that glass-rich lunar regolith should be activated by sodium hydroxide to ensure the aluminosilicate dissolution and form dense zeolitic products, whereas sodium silicate is more suitable for glass-free lunar regolith to assist the generation of amorphous products. Additionally, the temperature for the thermal curing of lunar geopolymers should exceed 60-80 ℃ for applicable 24-hour strength. Based on experimental characterizations and statistical analysis of existing data, three determinants of lunar geopolymer synthesis can be emphasized including the compatibility between activator and regolith activity, the calcium and alkali content of regolith, and the temperature of sealed thermal curing. These principles provide valuable guidance on the selection of regolith and activators along with the establishment of curing protocols towards future lunar constructions.
Construction of lunar bases is critical to further space exploration and decrease dependency on Earth-based resources. Abundant energy, water, and minerals on the Moon favor it as an ideal candidate for building extraterrestrial habitats. This paper discusses the feasibility of using in-situ resource utilization (ISRU) of lunar regolith (LR) for additively manufactured technologies for a lunar base. This work synthesizes current research in an overview at the intellectual level for the state-of-the-art methodologies of lunar regolith utilization in additive manufacturing (AM) processes. It makes a comparison of various techniques of AM, several kinds of materials, their maturity, and unique challenges of the lunar environment: extreme temperatures and microgravity. The review further discusses the impact of different types of post-processing treatments on the properties of LR-based materials and their applicability under real lunar conditions. These results allow the expectation of how AM technologies may work to provide a feasible and cost-effective construction process for the lunar base that will facilitate long-term space exploration missions.
Three-dimensional (3D) printing has been profoundly changing the production mode of traditional industries. However, this technique is usually limited to metre-scale fabrication, which prevents large-scale 3D printing (LS3DP) applications such as the manufacturing of buildings, aircraft, ships, and rockets. LS3DP faces great challenges, particularly, it not only requires confronting problems not yet solved by conventional 3D printing, such as the inability to print functional structures due to limitations by single-material manufacturing, but also needs to overcome the size effect limitation of large-scale printing. Here, we systematically review the state of the art in the integration of materials and technologies in LS3DP. We also demonstrate some disruptive engineering cases of LS3DP in the field of construction. The challenges and strategies for overcoming size constraints to achieve LS3DP of functional structures are discussed, including multifunctional 3D printing processes from nano- to large-scale and large-scale 4D printing processes, diverse printable materials and sustainable structures, horizontal and vertical size-independent printers, collaborative and intelligent control of the entire process, and extreme environment printing. These strategies can provide tremendous opportunities for the fully automated, intelligent, and unmanned production of these different material megastructures and internal multiscale multifunctional components such as buildings/structures, aerospace vehicles, and marine equipment.
Constructing a semi‐permanent base on the moon or Mars will require maximal use of materials found in situ and minimization of materials and equipment transported from Earth. This will mean a heavy reliance on regolith (Lunar or Marian soil) and water, supplemented by small quantities of additives fabricated on Earth. Here it is shown that SiO2‐based powders, as well as Lunar and Martian regolith simulants, can be fabricated into building materials at near‐ambient temperatures using only a few weight‐percent of carbon nanotubes as a binder. These composites have compressive strength and toughness up to 100 MPa and 3 MPa respectively, higher than the best terrestrial concretes. They are electrically conductive (>20 S m⁻¹) and display an extremely large piezoresistive response (gauge factor >600), allowing these composites to be used as internal sensors to monitor the structural health of extra‐terrestrial buildings.
The previous chapter provided an overview of the residential, commercial, and industrial dimensions of planning a city on Mars. Here, I offer a closer view of the buildings themselves. What kinds of structures are built in Earth’s most inhospitable environments? And what about space architecture itself? What has our experience designing and building habitats for people beyond Earth taught us about Martian building science, design, and engineering? While outer space habitats have been limited, people have experimented extensively with constructing analogs on Earth. What can we learn from that research?
In-situ resource utilization on the Moon and/or Mars is a cutting-edge hotspot for exploring outer space. Lunar/Martian regolith is an in-situ natural resource for construction habitats and objects on the Lunar or Martian surface. Various manufacturing technologies have been designed for exploration of and settlement in space and other planets. This review provides a comprehensive overview of the most recent studies on several additive manufacturing (AM) technologies that can be applied to the Moon/Mars, including updated research on the environmental effects of the AM fabrication process such as temperature, gravity, and the vacuum atmosphere and the introduction of in-situ materials utilization focusing on characteristics, beneficiation, and treatment of Lunar/Martian soils. In addition, this study presents several possible designs and construction strategies of habitats under the extreme environment of Moon and Mars, including the arrangement strategies of multifunctional base clusters and the AM technologies of multi-layer defense bases. As a necessary unmanned construction process prior to human settlement on the Moon/Mars, AM technologies open up new opportunities for fabrication of intricate three-dimensional (3D) objects on Moon/Mars and are becoming a major driving force for utilizing in-situ resources in outer space.
Cylindrical specimens of Martian and Lunar regolith simulants were molded using a simple salt water binder and sintered at various temperatures for comparing microstructure, mechanical properties and shrinkage. Material microstructure are reported using optical microscope and material testing is done using an MTS universal testing machine. A total of twenty samples were made for the Mars global simulant (MGS-1), and twenty more using Lunar mare simulant (LMS-1). The samples were split into groups of five and the sintering profiles were varied for each group. The specimens were fabricated via an injection molding method, designed to replicate typical masonary units manufactured via Binder Jetting Technique (BJT), an important additive manufacturing (AM) technique. Results show that for both the Martian and Lunar regolith that the optimal sintering temperature was somewhere between 1100°C and 1200°C. The compressive strength for both the Martian and Lunar masonary samples, that received optimal sintering conditions, was determined to be sufficient for construction of extraterrestrial structures. This work demonstrates the feasibility of implementing an accessible in-situ binder material, for either Martian or Lunar regolith, in order to construct extra-terrestrial masonary structures. The work provides a feasible path towards the direct implementation of BJT for the manufacturing of either Lunar or Martian masonary prisms.
The next step for the exploration of space seems to require the human participation by means of a long-lasting lunar outpost. Therefore, this paper attempts to review the up-to-date knowledge regarding prominent issues surrounding the construction stage of a permanent base on the Moon in the light of the 3D printing process. In this context, a number of significant and specific issues are presented and discussed in a detailed manner to determine both the state-of-the-art position of the related literature and the relevant fields for improvement and implications. As a result, the use of heterogeneous and collective swarms of ground robots through a decentralized approach seems reasonable for the 3D printing tasks. However, as it is an emerging technology, it has to be improved further and tested in a terrestrial context as well as on the Moon. In this regard, it is a must to investigate precisely if the solar energy will be adequate for the operation of robots during preparation, transportation, and printing processes of local and Earth-based construction materials. In terms of structural needs, a composite shelter, including (i) an inner inflatable shell with a three-layer membrane, (ii) an outer concrete layer with regolith, polymer, and reinforcing fibers, and (iii) an outermost shield with raw regolith, will likely be viable. However, sieving and binding issues during the preparation phase of concrete under vacuum and microgravity conditions must be solved efficiently.
The lunar regolith simulant based geopolymer was prepared, and its mechanical and structural properties under extreme temperature were investigated. Results show 7-day compressive strength of geopolymer cured at 60℃ was 58.8 MPa. After laboratory tests under extreme temperature, compressive strength of geopolymers under 120℃ and −30℃ were above 50.0 MPa and 80.0 MPa respectively. The extreme temperature resistance of geopolymers could be understood by the simulation results in terms of molecular structure stability, which reveals the stable aluminosilicate structures under lunar high temperatures and under ultra-low temperatures. After 40 cycles of thermal shocks (-196℃-25℃), compressive strength of geopolymer even increased explained by relatively dense microstructures through SEM and BET. The geopolymer based lunar concrete has demonstrated a great potential for in-situ lunar base construction.
As an example of Industry 4.0 in a project context, 3D printing of concrete has the potential to provide a paradigm shift for construction processes with significant implications for project management. This study investigates and reports the enablers and barriers of implementing the innovative 3D printing technology in construction projects, based on a literature review and case study interviews in construction companies. 3D printing can make construction processes more effective, provided that project managers can utilize the potential. The interviews with industry representatives highlighted the issue of cost efficiency of the technology. There is a need to show practical project examples on cost efficiency of the 3D printing technology. To those who manage new technologies 3D printing and other aspects of Industry 4.0 represent an opportunity, while those who struggle to work with and understand new technologies, they represent a challenge or even a threat. Future project managers better be in the first category.
KLS-1 Lunar regolith simulant was microwave sintered to explore its potential applicability in future lunar construction. The effects of sintering temperature on linear shrinkage, density, porosity, and microstructural, mechanical, and thermal properties were investigated. As the sintering temperature increased, linear shrinkage and density increased and porosity decreased. Structural evolution in the sintered samples was characterized by scanning electron microscopy and X-ray diffraction. Unconfined compressive strength testing showed that mechanical strength increased significantly with increasing sintering temperature, with 1120 °C giving the highest strength of 37.0 ± 4.8 MPa. The sintered samples exhibited a coefficient of thermal expansion of approximately 5 × 10⁻⁶ °C⁻¹, which was well-maintained even after cyclic temperature stress between −100 and 200 °C. Therefore, this microwave processing appears promising for the fabrication of building material with sufficient mechanical strength and thermal durability for lunar construction.
Using Martian resource to construct a site on Mars is a superior choice to instead of transporting all the construction materials from Earth to the Mas with incredibly high cost. This study proposes a developed Martian concrete composed of sulfur and magnetite, heated by microwave to meet the energy-poor environment on Mars. A lattice Boltzmann model is developed to determine the optimal microwave power and heating time for Martian concrete casting. The compressive strength and microstructure of Martian concrete casted by microwave are measured by test. Finally, a 3D printed device is conceived to prepare Martian concrete and the four-layered specimen is casted to simulate the 3D print process. The results indicate that the compressive strength of Martian concrete casted by microwave can reach 1.78 kgf/mm² (17.44 MPa) on earth, which is corresponding to 4.62 kgf/mm² on Mars. Since the heating rate of magnetite under microwave is very high, if possible, the low microwave power and long heating time should be chosen to reduce the temperature gradient in matrix and reduce the possibility of sulfur matrix boiling. In addition, the strength of four-layered (simulated 3D printed) Martian concrete can reach 1.21 kgf/mm² (11.86 MPa) on earth, which is corresponding to 3.15 kgf/mm² on Mars.
For long term space exploration it will be necessary to build a safe infrastructure and experimental research facilities for human scientists providing efficient working conditions and protecting against the environment. To construct structures on the moon one has to select proper materials considering strength and cost of production and supply. Concrete is a widely used material for building any kind of structure on the earth. Concrete is also a good candidate as construction material on the moon, but has to fit the lunar environment and the economic realities. This paper presents a pilot effort to investigate the efficacy of waterless concrete using mostly ISRU material for the robotic fabrication and installation of prefabricated elements. The first concrete bricks have been "cast" by the small research group. The results of testing the first lunar concrete specimens using polymers as binder will be presented at the conference.
For long duration missions on other planetary bodies, the use of in situ materials will become increasingly critical. As man’s presence on these bodies expands, so must the structures to accommodate them including habitats, laboratories, berms, garages, solar storm shelters, greenhouses, etc. The use of in situ materials will significantly offset required launch upmass and volume issues. Under the auspices of the In Situ Fabrication & Repair (ISFR) Program at NASA/Marshall Space Flight Center (MSFC), the Habitat Structures project has been developing materials and construction technologies to support development of these in situ structures. This paper will report on the development of several of these technologies at MSFC’s Prototype Development Laboratory (PDL). These technologies include, but are not limited to, development of extruded concrete and inflatable concrete dome technologies based on waterless and water-based concretes, development of regolithbased blocks with potential radiation shielding binders including polyurethane and polyethylene, pressure regulation systems for inflatable structures, production of glass fibers and rebar derived from molten lunar regolith simulant, development of regolithbag structures, and others, including automation design issues. Results to date and planned efforts for FY06 will also be presented.
Several unique systems including the Lunar Electric Rover, the unpressurized Chariot rover, the versatile light-weight crane and Athlete cargo transporter as well as the habitat module mockups and a new generation of spacesuits are undergoing coordinated tests at NASA's facility for Desert Research and Test Studies (D-RATS). A synergetic plan is proposed for utilizing these maturing systems coupled with a fabrication technology called Contour Crafting, tailored for swift and reliable lunar infrastructure development. The intent is to increase astronaut safety, improve buildup performance, ameliorate lunar dust interference and concerns, and reduce time-to-commission, all in an economic manner.
Civil Engineering is getting prepared for operations in space. The Moon will presumably be the focal point in this new era. Civil Engineering professionals, in close cooperation with other scientists and engineers are in the phase of planning operations on the Moon. The experience gained on the Earth through four millenniums is now on the eve of being applied in a new environment. In this paper, an assessment is aimed to show the new challenges of Civil Engineering in front of this new Nature, and the necessary considerations for surpassing the difficulties. Different aspects of the problem, with similarities and differences as compared to applications on the Earth, like choice and design of the structures, methods of construction, project management and cost engineering, use of imported and local materials, mounting and fabrication on the Moon are discussed.
3D-printing technologies are receiving an always increasing attention in
architecture, due to their potential use for direct construction of
buildings and other complex structures, also of considerable dimensions,
with virtually any shape. Some of these technologies rely on an
agglomeration process of inert materials, e.g. sand, through a special
binding liquid and this capability is of interest for the space
community for its potential application to space exploration. In fact,
it opens the possibility for exploiting in-situ resources for the
construction of buildings in harsh spatial environments. The paper
presents the results of a study aimed at assessing the concept of 3D
printing technology for building habitats on the Moon using lunar soil,
also called regolith. A particular patented 3D-printing technology -
D-shape - has been applied, which is, among the existing rapid
prototyping systems, the closest to achieving full scale construction of
buildings and the physical and chemical characteristics of lunar
regolith and terrestrial regolith simulants have been assessed with
respect to the working principles of such technology. A novel lunar
regolith simulant has also been developed, which almost exactly
reproduces the characteristics of the JSC-1A simulant produced in the
US. Moreover, tests in air and in vacuum have been performed to
demonstrate the occurrence of the reticulation reaction with the
regolith simulant. The vacuum tests also showed that evaporation or
freezing of the binding liquid can be prevented through a proper
injection method. The general requirements of a Moon outpost have been
specified, and a preliminary design of the habitat has been developed.
Based on such design, a section of the outpost wall has been selected
and manufactured at full scale using the D-shape printer and regolith
simulant. Test pieces have also been manufactured and their mechanical
properties have been assessed.
The moon has recently regained the interest of many of the world's space agencies. Lunar missions are the first steps in expanding manned and unmanned exploration inside our solar system. The moon represents various options; it can be used as a laboratory in low gravity, it is the closest and most accessible planetary object from the Earth, and it possesses many resources that humans could potentially exploit. This paper has two objectives: to review the current status of the knowledge of lunar environmental requirements for future lunar structures, and to attempt to classify different future lunar structures based on the current knowledge of the subject. The paper divides lunar development into three phases. The first phase is building shelters for equipment only; in the second phase, small temporary habitats will be built, and finally in the third phase, habitable lunar bases will be built with observatories, laboratories, or production plants. Initially, the main aspects of the lunar environment that will cause concerns will be lunar dust and meteoroids, and later will include effects due to the vacuum environment, lunar gravity, radiation, a rapid change of temperature, and the length of the lunar day. This paper presents a classification of technical requirements based on the current knowledge of these factors, and their importance in each of the phases of construction. It gives recommendations for future research in relation to the development of conceptual plans for lunar structures, and for the evolution of a lunar construction code to direct these structural designs. Some examples are presented along with the current status of the bibliography of the subject.
Sulfur and sulfur compounds have a wide range of applications for their
fluid, electrical, chemical, and biochemical properties. Although known
abundances on the Moon are limited (approximately 0.1 percent in mare
soils), sulfur is relatively extractable by heating. Coproduction of
sulfur during oxygen extraction from ilmenite-rich mare soils could
yield sulfur in masses up to 10 percent of the mass of oxygen produced.
Sulfur deserves serious consideration as a lunar resource.
A lunar base is an essential part of all the new space exploration programs because the Moon is the most logical first destination in space. Its hazardous environment will pose challenges for all engineering disciplines involved. A structural engineer's approach is outlined in this paper, discussing possible materials and structural concepts for second-generation construction on the Moon. Several different concepts are evaluated and the most reasonable is chosen for a detailed design. During the design process, different solutions—for example, for the connections—were found. Although lunar construction is difficult, the proposed design offers a relatively simple structural frame for erection. A habitat on the Moon can be built with a reasonable factor of safety and existing technology. Even so, we recognize the very significant difficulties that await our return to the Moon.
Martina Pinni is a registered architect with an interest in high-tech buildings, extreme environments, and spinoff applications of space technology in building construction. Her thesis in architecture focused on an interior design for a space habitation module (2000). Her professional experience includes 6 years of technical and commercial positions in façade engineering, architectural design, and research (2001-2007). Teaching experience includes three semesters as faculty assistant of building technology at the University IUAV of Venice (2006-2007), and current position in astronaut training-structures, thermal control, life support system, emergencies-at ESA-EAC Cologne for the International Space Station project (2008-present). She earned a Laurea (M. Arch.) from the University IUAV of Venice (2000), an MS from the University of Houston, Space Architecture (2004), and attended the ISU SSP’07 at BeiHang University in Beijing (2007).
An important step in the exploration and colonization of the solar system is to build a permanently inhabited base on the Moon. The lunar environment is stark and hostile to unprotected humans. Structures are needed that protect the inhabitants from vacuum, radiation, extreme temperatures, dust, and meteoroids. Transporting the necessary construction materials from Earth is extremely expensive. Fortunately, lunar structures can be built utilizing indigenous materials. The locally available materials include lunar regolith, cast regolith, glass and glass composites, metals and concrete. Their mechanical properties are summarized and their suitability for lunar construction is evaluated. The most promising materials are cast regolith and lunar glass. Several lunar bases concepts utilizing indigenous materials are described and evaluated. Precast modules and large cast in place structures can be fabricated from lunar concrete. Large cylindrical modules, curved and flat panels and arches cast from lunar regolith are also feasible. A tied arch system is considered very promising because of its structural efficiency.
This paper presents the physical properties and chemical composition of hydrates formed under steam conditions. The test specimens were made with cement as well as individual compounds. A comprehensive study on the characteristics of hardened hydrates in a microscopic scale was carried out. An improved polymerization of silicate anions resulting in an increased CaO/SiO2 ratio at an elevated temperature was verified by the nuclear magnetic resonance spectroscopy (NMR) analysis. Dense microstructures of hydrates and low content of Ca(OH)2 crystals were observed by the scanning electron microscope (SEM), energy dispersive spectromer (EDS), environmental scanning electron microscope (ESEM), thermogravimetric analyzer (TGA), and x-ray dtffractrometer (XRD) tests. Mercury intrusion porosimetry (MIP) had been used to examine the pore structures of hydrates. It revealed that the hardened paste made with the dry-mixture/steaminjection (DA/57) method developed microstructures with low porosity, small pore radius, and larger surface areas. These observations agree with the NMR/TGA test results. This paper also discusses the effects of sample fineness and compaction on the hydrate's microstructures formed under steam environment. The test results verify the validity of the DMSI concept.
This paper discusses the basic concept of steam hydration and presents test data on heat of hydration by exposing cement compounds to pressurized steam. The test samples include cement and its individual compounds; tricalcium silicate (C 3S), dicalcium silicate (C 2S), tricalcium aluminate (C 3A), and tetracalcium aluminoferrite (C 4AF). For a compacted 10 grams C 3S sample, the heat of hydration was determined as 209 cal/g. All samples except C 3A hardened during steaming. Nonetheless, the C 3A samples reacted very rapidly with steam and registered a 91 C temperature rise during the test. This paper also discusses effects of sample's fineness and degree of compaction on heat evolution and hydrate morphology during exposure to steam. The test results verify the validity of the dry-mix/steam-injection (DMSI) concept.
Introduction: When humans return to the Moon, In-Situ Resource Utilization (ISRU) of lunar regolith will allow a more efficient, less costly, and thus, a more sustainable human presence on the Moon to be achieved. Maintaining a human presence on the Moon will require methods to mitigate lunar dust, provide protection from micro-meteoroid impact, and reduce astronaut exposure to radiation. It would also be desirable to grow plants at the outpost, both for food and other life support purposes. Furthermore, extraction of resources such as Helium-3, metals, and oxygen from lunar regolith would also be of value. © 2012 Springer-Verlag Berlin Heidelberg. All rights are reserved.
Contour Crafting is a digitally controlled construction process invented by Professor Behrokh Khoshnevis that fabricates components directly from computer models, using layered fabrication technology. By obviating the need for formwork used in traditional concrete construction, CC can reduce costs and construction times significantly. The technique has great potential as a robotic form of construction reliant on relatively minimal human labor as a form of construction in relatively hazardous environments, such as the Moon with its radiation levels that can prove highly damaging. Current research funded by NASA has been exploring the potential for using CC on the Moon to build structures making use of readily available regolith that is found in great abundance on the surface of the Moon. This article offers an overview of this research and evaluates the merits of using CC on the Moon.
Meteorite impact on the lunar surface produces a consistent, broadly graded soil. In this note, the geotechnical and geological systems are compared to characterize lunar soil. In geotechnical terms, the lunar soil particle size distribution is described as sandy silt/silty sand, well-graded. In geologic terms, it is described as very fine sand, very poorly sorted, nearly symmetrical, and mesokurtic. Because of its broad particle size distribution, lunar soil may be internally erodible.
Evaporation experiments were performed in vacuo on the multicomponent melt, FeO-MgO-SiO2-CaO-Al2O3 with the solar elemental abundances. The analysis of experimental results shows that the rate-determining step of evaporation is the vaporization reactions occurring on the melt surface, amongst other possible rate processes. The reaction modes are determined for the components, FeO, MgO and SiO2. FeO, unlike other components, vaporizes through the disproportionation reaction into metallic and ferric irons in the melt phase. ‘Volatility’ is defined as a physical quantity so as to describe the evaporational fractionations of elements. On the basis of this concept, the experimental results of the present and previous works together with thermodynamic data are organized to characterize the evaporation sequence of primitive condensed materials. Its gross feature is the sequential evaporation of the components in the order of Fe, Mg, Si, Ca and Al. The details of the evaporation sequence depend on temperature and initial valences of Fe. The evaporation sequence is comparatively discussed with the condensation sequence of the nebular gas, which has been well examined by previous workers. Both sequences, combined together, provide a basic framework to clarify the chemical fractionation processes which have differentiated primitive materials into the planetary and meteoritic materials. The chemical diversity of chondrules and inclusions in meteorites is interpreted as mainly due to the evaporational or condensational fractionation, but it also invokes other processes such as metal/silicate separation and non-equilibrium reaction with a surrounding gas.
This paper will describe the ISS TransHab architectural design being proposed as a habitation module for the International Space Station. TransHab is a space inflatable habitation module that originally was designed to support a crew of six as a transit habitat (TransHab) to and from Mars. A team of architects and engineers at the Johnson Space Center has been designing and testing this concept to make it a reality.
Samples consisted of JSC-1 regolith simulant, melted purified sulfur and glass fiber hand-drawn from regolith were cast and tested in a four-point bend test. Stress and deflections of the control samples (without glass fibers) and samples containing 1% glass fibers by mass were made. The glass fibers made from melted JSC-1 simulant, were mainly produced by hand-draw process. Initial test results showed that the ultimate strength can significantly improve with the addition of fiber glass, derived from the lunar regolith simulant. Using a mathematical code created by Langley Research Center, the radiation shielding effectiveness of sulfur/regolith concrete and other composite materials were analyzed. The mathematical code is a good tool to compare the radiation shielding effectiveness of different materials. This comparison was presented in this paper.
Construction of permanent settlements on the Moon will be greatly facilitated by the use of local building materials. The structural materials normally employed in Terrestrial construction (steel, Portland Cement concrete, wood and masonry) are to a great extent unavailable on the Moon. (Steel and Lunar-style masonry may eventually be fully available — but concrete requires large quantities of water, and wood will not be an option.) The Lunar surface does, however, feature large quantities of basaltic rock, which is already employed on Earth as an industrial material. Cast Basalt has many desirable structural properties — yet its ultimate failure mode is brittle fracture, especially under bending loads, which is highly undesirable. This design note will discuss one option for scaling up Terrestrial experience with Cast Basalt as an industrial material, to use in larger castings for structural construction on the Moon. Post-tensioning of the basaltic castings, based on Terrestrial experience with reinforced concrete structures, will be outlined. Post-tensioning will enhance the use of these elements for building crewed habitations. Using a tensile material to compress the more brittle basaltic casting will transform the combined structural element from a brittle into a ductile material, for purposes of structural design and risk evaluation. In the Lunar environment, with internal air pressure being the dominant loading for inhabited structures, ductility of the structural elements will be a vital need.
The structure for the human habitat in either a lunar or Martian base must be efficient, reliable, functional and economical. In addition to the specific needs for structural adequacy and efficiency, the structure must be consistent with the overall habitat design by being supportive of other critical criteria, including minimal stowage mass and volume, ease of deployment and minimal associated astronaut time and construction equipment, integration of the structure with the habitat operations and life support systems, and the outfitting and placement of contents within the habitat. The conceptual design of a proposed structural configuration addressing these criteria is described, including through computer-generated visualization, some preliminary calculations, and examination of major design concerns. The basic unit of the modular system proposed is a three-level 9-meter diameter inflatable membrane spherical shape shipped stowed around a core containing extendable side and top/bottom support members and rings, along with other structural members, equipment, and stable habitat supplies. Much of the deployment on site is accomplished through pressurization of the unit as this pulls the support members and the rings attached to membrane from the core and into position. An internal support rib system adjacent to the membrane and spanning between the support rings, along with other interior structural elements and fixtures, are placed by the mission members in a pressured environment. The system is designed to minimize deployment and outfitting effort, shipping volume, and the need to move materials through an airlock into the pressurized module. Adjacent modules are joined structurally and functionally through the side rings.
Inflatable structures have wide applications in space, ranging from large low pressure satellite balloons to human occupied structures on extraterrestial surfaces. Among their desirable attributes are their lightweight nature, small stowage volumes, easy deployability, and efficiency as pressure vessels. Inflated membranes are load adaptive structures which generally display a nonlinear response resulting from possible large movements upon loading. The shape of an inflatable structure is key to its feasibility and efficiency. The general structural behavior of inflated membrane structures, methods for controlling their shape, and other design considerations for inflatable structures utilized in space are described.
This paper presents general information regarding lunar materials and Hokkaido anorthite and the basic concept of lunar cement formulation. Hokkaido anorthite consists of 16 wt.% of calcium oxide and is considered a candidate material for the proposed lunar cement production study. An electric furnace capable of generating heat up to 1600 C was used to conduct several bench burns using Hokkaido anorthite as simulant. The sintering temperature and duration were 1450 C and one hour, respectively. Two types of lunar cements with fineness ranging from 2670 to 5000 Blaine were made. The conventional wet mix procedure and the Dry-Mix/Steam-Injection (DMSI) method developed by T.D. Lin were applied to make a series of 4 cm mortar cubes for compression tests. The wet-mix cubes developed 2.9 N/mm² after 7 days of curing in a moist room while the DMSI cubes developed 21.9 N/mm² after 24 hours of steaming at 170 C. Scanning Electronic Microscopic analyses and X-Ray Diffraction analyses were performed to determine the morphology and chemical compositions of the obtained hydrates. This paper also discusses Japan's current interest and initiatives in the space technology development. This project was carried out with a support from Hokkaido Space Technology Consultative Association. It is hoped that the results of this test program will be a contribution to the international community on lunar concrete and space development.
The effects of vacuum and microgravity on the hydration of cement are primary concerns regarding casting concrete both on the moon and in space. Previous studies by others have focused on the behavior and mechanical properties of concrete cast in a vacuum without addressing the microstructural characteristics of the paste. More recently, an experiment was carried out onboard a space shuttle to investigate the effect of microgravity on cement hydration. In the present study, mortars hardened in a vacuum for 4 to 12 hours and control mortars not exposed to a vacuum were studied by light microscopy and scanning electron microscopy in order to examine differences in microstructural and microchemical characteristics. The principal findings, that rapid loss of water from the fresh mortar leads to frothy texture, poor cement hydration and paste development, and low compressive strength, appears to preclude casting water-rich mortar or concrete in a vacuum.
In this paper we review the design principles for optimized two-stage concentrators in the context of applications in the lunar environment and discuss the characteristics and properties of some of the nonimaging secondaries which could be employed. In particular we address the potential for using solar energy for the production of cement from lunar materials which will require extremely high temperatures. The generation of such temperatures, in the range 1400 degrees C to 2200 degrees C, will require very high levels of solar flux concentration incorporating some form of ideal or near ideal nonimaging concentrator. The maximum relative benefit will be provided by the secondary in cases where φ, the rim angle of the primary, is small, that is, for systems with relatively large focal length to diameter (F/D) ratios. The design parameters and trade-offs for each of these systems including strategies for choice of particular secondary and degree of truncation, are discussed. The principles underlying the design of these optical systems are summarized with specific emphasis on their comparative advantages for deployment in space and lunar environments.
To cast concrete on the Moon requires a new procedure to overcome the ill-suited vacuum condition. The proposed new procedure is to mix cement and aggregate in a dry state and expose the mixture to steam in a confined chamber to enforce hydration at elevated temperatures and pressures. A test program was carried out at the National Chiao Tung University in 1993 to verify the concept of the proposed Dry-Mix/Steam-Injection (DMSI) procedure. The hydration mechanism of a dry cement mixture with high temperature steam differs from that of the conventional wet mix procedure in two ways. First, a rapid transfer of thermal energy from steam causes the cement particles to raise their activation energy to expedite a complete hydration. Second, steam particles are very small, in the order of 3 Angtron in diameter, capable of penetrating micron pores inhibited in cement particles. Concrete thus made developed a high strength of 700 kgf/cm² (10,000 psi) after 18 hours of steaming at 180 C. It is approximately 2.5 times that of companion concrete made with the conventional wet-mix procedure after 28 days of moist curing. Another test series revealed that the DMSI method required only 50% of the cement needed in making concrete of an equivalent strength of 560 to 630 kgf/cm2 (8000 to 9000 psi) through the wet-mix procedure.
In view of potential application as a construction material on the lunar surface the mechanical integrity of sulfur concrete was evaluated after being subjected to simulated temperature cycles. Here, small cubes of sulfur concrete were repeatedly cycled between room (20 °C) and liquid nitrogen (−191 °C) temperatures after which they, and non-cycled cubes, were evaluated by compression testing. The compression strength of the non-cycled samples averaged ∼35 MPa (5076 psi) before failing whereas the cycled samples fractured at about 7 MPa (1015 psi). Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate whereas it was seen adhering in those non-cycled. Based on a simple analysis it was concluded that the large strength discrepancy between cycled and non-cycled samples is due to differences between the coefficients of thermal expansion of the materials constituting the concrete.
The Moon is key to understanding both Earth and our Solar System in terms of planetary processes and has been a witness of the Solar System history for more than 4.5 Ga. Building on earlier telescopic observations, our knowledge about the Moon was transformed by the wealth of information provided by Apollo and other space missions. These demonstrated the value of the Moon for understanding the fundamental processes that drive planetary formation and evolution. The Moon was understood as an inert body with its geology mainly restricted to impact and volcanism with associated tectonics, and a relative simple composition. Unlike Earth, an absence of plate tectonics has preserved a well-defined accretion and geological evolution record. However recent missions to the Moon show that this traditional view of the lunar surface is certainly an over simplification. For example, although it has long been suspected that ice might be preserved in cold traps at the lunar poles, recent results also indicate the formation and retention of OH− and H2O outside of polar regions. These volatiles are likely to be formed as a result of hydration processes operating at the lunar surface including the production of H2O and OH by solar wind protons interacting with oxygen-rich rock surfaces produced during micrometeorite impact on lunar soil particles. Moreover, on the basis of Lunar Prospector gamma-ray data, the lunar crust and underlying mantle has been found to be divided into distinct terranes that possess unique geochemical, geophysical, and geological characteristics. The concentration of heat producing elements on the nearside hemisphere of the Moon in the Procellarum KREEP Terrane has apparently led to the nearside being more volcanically active than the farside. Recent dating of basalts has shown that lunar volcanism was active for almost 3 Ga, starting at about 3.9–4.0 Ga and ceasing at ∼1.2 Ga. A recent re-processing of the seismic data supports the presence of a partially molten layer at the base of the mantle and shows not only the presence of a 330 km liquid core, but also a small solid inner core. Today, the Moon does not have a dynamo-generated magnetic field like that of the Earth. However, remnant magnetization of the lunar crust and the paleomagnetic record of some lunar samples suggest that magnetization was acquired, possibly from an intrinsic magnetic field caused by an early lunar core dynamo. In summary, the Moon is a complex differentiated planetary object and much remains to be explored and discovered, especially regarding the origin of the Moon, the history of the Earth–Moon system, and processes that have operated in the inner Solar System over the last 4.5 Ga. Returning to the Moon is therefore the critical next stepping-stone to further exploration and understanding of our planetary neighborhood.
In Situ Resource Utilization (ISRU) refers to the in situ generation of consumables for autonomous or human activities from raw materials found on the Moon or other planetary bodies. The use of ISRU on the Moon may provide a means of reducing the cost and risk of human exploration of the Moon and beyond, and an impetus for commercial contributions to lunar exploration. Potential products include O2 and H2O for life support, H2 and O2 for fuel and propellant, and other elements and compounds for metallurgic and chemical production processes.
If ISRU is to be applied successfully on the Moon, it is important that landing site selection, surface operations and suitable ISRU technologies are identified using knowledge of the availability and distribution of lunar resources and detailed understanding of the workings of the various processes available. Here, we review current knowledge of chemical and mineralogical resources on the Moon which can be used in the development of ISRU as a realistic component of future lunar exploration.
A review of concrete basics is presented to provide a general background for discussions of the potential uses of concrete on the Moon and Mars. Problems associated with production of cement, mixing methods, water introduction methods, curing methods, and reclamation of free water are discussed. An example concrete mix design using precise slabs to cover a habitat is presented. The example shows that for 42 cubic yards of concrete, 23,688 pounds of cement and 1,370 pounds of water are required for a water-to-cement ration of 0.48. Only about 5,685 pounds of water is needed for cement hydration. The balance of the water is free water and should be reclaimed or methods devised for dry mixing and adding just enough water to hydrate the cement. Recommendations for further experimental research are presented.
The objective is to design a pressurized shelter build of indigenous lunar material. The topics are presented in viewgraph form and include the following: lunar conditions which impact design; secondary factors; review of previously proposed concepts; cross section of assembly facility; rationale for indigenous materials; indigenous material choices; cast basalt properties; design variables; design 1, cylindrical segments; construction sequence; design 2, arch-slabs with post-tensioned ring girders; and future research.
Anorthite rocks found in Hokkaido, Japan have chemical compositions similar to those of lunar anorthite rocks brought back from Highland regions of the Moon. Because of the compositional similarity, Hokkaido anorthite was used in this laboratory study in which simulated lunar cement was made through a high temperature sintering process, rapid quenching, and proper grinding. The needed mortar was prepared by mixing one part of the obtained lunar cement (or Portland cement for reference cubes) and two parts of river sand that met the JIS requirements. The Dry-Mix/Steam-Injection (DMSI) method that was developed solely for the future lunar construction and the conventional wet-mix procedure that was intended to make reference cubes were applied to make series of 40 mm mortar cubes. All test cubes including the wet-mix ones after 28-day curing in a moist room were subjected to compression tests at 1(DMSI), 3(wet-mix), 7, 28, and 180 days(only OPC-DMSI) of moist curing. Measured compressive strengths for wet-mix cubes made with simulated lunar cement were relatively low, only 5.8 N/mm², and those of DMSI cubes were remarkably high, 24.3 N/mm², after 180 days of air curing. Samples of tested cubes at 0, 20, 60, 270, and 330 days of vacuum exposure of 10–4 torr were tested to determine pore-size distributions and incremental pore as well as cumulative pore-volumes at selected vacuum exposure ages. It concluded that the DMSI cubes showed no imminent pore-size changes but the wet-mix cubes had surprising variations. This paper presents quantitative data on effect of vacuum on simulated lunar cement mortar. This preliminary study program produced useful information that signifies the applicability of concrete to future lunar construction. Nonetheless, a one-year time frame is too short for a vacuum related durability study. We hope to carry out a more comprehensive test program with a minimum of 3-year time frame for the follow-up study.
This study aims to investigate the characteristics and engineering properties of the dry-mix/steam-injection method (DMSIM) which was developed to overcome difficulties involved in vacuum conditions of the lunar environment. A comparison was made to examine the differences in the hydration process, mechanical properties and the composition of hydration products between DMSIM and the normal-temperature wet-mix method (NTWMM). In DMSIM, when dry cement particles come in contact with steam, heat immediately transfers from the steam to the cement, with part of the steam being forced into the inner regions of the cement particles via the micropores. As cement particles gain activation energy and moisture condensed from steam, they undergo rapid and complete hydration. Test results showed that the optimal steaming temperature for dry-mix samples of cement and standard sand is 180–200°C and the optimal steaming scenario for 10 cm3 samples of concrete is at 200°C for 18 h. The present DMSIM has advantages of lower cement content, shorter hardening time and higher concrete strengths, as compared to NTWMM.
The studies reported in this paper were undertaken to evaluate the maximum use of lunar in situ resources for surface construction, such as a habitat structure for a permanent manned lunar base. This type of activity is well into the future, but there are possible near-term applications that could utilize in situ resources for protection from radiation of surface power reactors, solar flares, and micrometeorite damage. "Waterless" concrete made of sulfur, a by-product material of oxygen and carbon extractions, is a viable alternative to hydraulic cement. Sulfur-lunar regolith concrete is an ideal material for building structures on the moon. Its availability, high strength, and durability properties make it a very attractive candidate for the development of the first lunar-construction activities. Regolith-derived glass rebar and fiber can also be used with "concrete" made with in situ regolith. Development of such habitats pose tremendous challenges that can be met by the combination of innovative design with cutting-edge technologies that are appropriate for planetary surface habitats with multiple applications for Earth and beyond.
Studies on lunar base construction conducted by the writers' research group are summarized. A desirable lunar base design was first discussed by employing a systems engineering approach and by defining an evolutionary scenario, which emphasized resource utilization. Several lunar-base-related concepts were examined from the viewpoint of construction engineering including construction materials, structural design, and construction methods. The research also addressed resource utilization for the production of oxygen and construction materials. A commercial approach toward future lunar development is proposed.
This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions such as impact and space radiation on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target small sulfur concrete samples. The lunar concrete samples have been prepared using JSC-1 lunar simulant, produced by Johnson Space Center, as an aggregate addition. The sample was placed in the MSFC Impact Test Facility’s Micro Light Gas Gun’ target chamber, and was struck by a 1-mm diameter (∼1.4e−03g) aluminum projectile at 5.85km/s. A detailed analysis of the damage caused by a catastrophic event could help design the size, shape, and placement of individual structures in the base to minimize detrimental effects. The effectiveness of sulfur concrete subjected to space radiation was analyzed using HZETRN mathematical code, provided by NASA. A concrete wall made of sulfur and JSC-1 simulant would need to be thicker than a wall made of plain JSC-1 simulant to provide the same amount of protection. Test results were presented, discussed and put into the context of the lunar environments.
Improved versions of Lunar Prospector thermal and epithermal neutron data were studied to help discriminate between potential delivery and retention mechanisms for hydrogen on the Moon. Improved spatial resolution at both poles shows that the largest concentrations of hydrogen overlay regions in permanent shade. In the north these regions consist of a heavily cratered terrain containing many small (less than ∼10-km diameter), isolated craters. These border circular areas of hydrogen abundance ([H]) that is only modestly enhanced above the average equatorial value but that falls within large, flat-bottomed, and sunlit polar craters. Near the south pole, [H] is enhanced within several 30-km-scale craters that are in permanent shade but is only modestly enhanced within their sunlit neighbors. We show that delivery by the solar wind cannot account for these observations because the diffusivity of hydrogen at the temperatures within both sunlit and permanently shaded craters near both poles is sufficiently low that a solar wind origin cannot explain their differences. We conclude that a significant portion of the enhanced hydrogen near both poles is most likely in the form of water molecules.
The century-old Mond process for carbonyl extraction of metals from ore
shows great promise as an efficient low energy scheme for producing
high-purity Fe, Ni, Cr, Mn, and Co from lunar or asteroidal feedstocks.
Scenarios for winning oxygen from the lunar regolith can be enhanced by
carbonyl processing of the metallic alloy by-products of such
operations. The native metal content of asteroidal regoliths is even
more suitable to carbonyl processing. High-purity, corrosion resistant
Fe and Ni can be extracted from asteroidial feedstocks along with a
Co-rich residue containing 0.5 percent platinum-group metals. The
resulting gaseous metal carbonyl can produce a variety of end products
using efficient vapor forming techniques.
Results are presented of a series of test programs to investigate
physical properties of concrete made with Apollo 16 lunar soil as
aggregate, lunar cement production, the preliminary design of a concrete
lunar base, and effects of lunar temperatures on concrete elements. The
results verified the lunar concrete concept. A dry-mix steam-injection
concreting procedure developed for making concrete in a vacuum
environment is discussed. Measured strengths for concrete made with 18
hr of steaming at 180 C reached 69 MPa (10,000 psi). The compositions of
selected lunar materials, and concrete strengths at 160-180 C are shown.
The artificial atmospheric pressure within an inflatable-structure lunar
base can be substantially decreased if the oxygen partial pressure is
increased by a sufficient amount; this will allow substantial
shipping-cost savings without inducing hypoxia or hyperoxia. In
addition, reductions in structural material strengths and/or structural
component dimensions may be possible. The size of the containers
required for shipment of atmospheric gases can then also be reduced.
Experiments were conducted to study the sintering behavior of glass and
basalt lunar soil simulants. The degree of sintering was assessed by
compressive strength testing and microanalysis. Both crushed glass and
basalt sinter significantly at 1000 C, with the basalt attaining its
maximum strength at 1100 C. Initial sintering occurs in less than 15
min, and the degree of sintering does not increase significantly with
time after about 30 min. Glass sinters more readily than crystalline
material. Sintering and devitrification both occur on a time scale of
minutes in the heated glass, but sintering is apparently more rapid. The
processes of sintering and oxygen release by hydrogen reduction of lunar
soil are synergistic, and could be combined to produce two extremely
useful products at a lunar base.
Durability of sulfur concrete with different fillers, as well as Portland cement concrete, was tested in the solutions of HCl, H2SO4, and NaCl. Regarding mass changes, in the solutions of HCl and H2SO4 sulfur concrete with talc and fly ash exhibited higher durability, while in NaCl samples with alumina and microsilica were better. The type of filler did not affect durability regarding compressive strength. Strength loss was higher in the solution of HCl comparing to H2SO4, while negligible in NaCl which is in accordance with apparent porosity increase. Portland cement concrete after two months lost 20% of mass.Highlights► Sulfur concrete samples are made of modified secondary sulfur, sand, and fillers. ► Durability of sulfur concrete is investigated in 10% HCl, 20% H2SO4 and 3% NaCl. ► Compressive strength loss is higher for samples treated by HCl compared to H2SO4. ► Compressive strength loss is negligible after treatment in NaCl. ► Apparent porosity increase is in agreement with compressive strength loss.
Melting sulfur and mixing it with an aggregate to form “concrete” is commercially well established and constitutes a material that is particularly well-suited for use in corrosive environments. Discovery of the mineral troilite (FeS) on the moon poses the question of extracting the sulfur for use as a lunar construction material. This would be an attractive alternative to conventional concrete as it does not require water. However, the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. Here it is assumed that the lunar ore can be mined, refined, and the raw sulfur melded with appropriate lunar regolith to form, for example, bricks. This study evaluates pure sulfur and two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar stimulant and SiO2 powder as aggregate additions. Each set was subjected to extended periods in a vacuum environment to evaluate sublimation issues. Results from these experiments are presented and discussed within the context of the lunar environment.
How do we begin to expand our civilization to the Moon? What are the technical issues that infrastructural engineers, in particular, must address? This paper has the goal of introducing this fascinating area of structural mechanics, design, and construction. Published work of the past several decades about lunar bases is summarized. Additional emphasis is placed on issues related to regolith mechanics and robotic construction. Although many hundreds of papers have been written on these subjects, and only a few tens of these have been referred to here, it is believed that a representative view has been created. This summary includes environmental issues, a classification of structural types being considered for the Moon, and some possible usage of in situ resources for lunar construction. An appendix provides, in tabular form, an overview of structural types and their lunar applications and technology drivers.
The unique properties of lunar regolith make for the extreme coupling of the soil to microwave radiation. Space weathering of lunar regolith has produced myriads of nanophase-sized Fe 0 grains set within silicate glass, especially on the surfaces of grains, but also within the abundant agglutinitic glass of the soil. It is possible to melt lunar soil i.e., 1,200– 1,500° C in minutes in a normal kitchen-type 2.45 GHz microwave, almost as fast as your tea-water is heated. No lunar simulants exist to study these microwave effects; in fact, previous studies of the effects of microwave radiation on lunar simulants, MLS-1 and JSC-1, have been misleading. Using real Apollo 17 soil has demonstrated the uniqueness of the interaction of microwave radiation with the soil. The applications that can be made of the microwave treatment of lunar soil for in situ resource utilization on the Moon are unlimited.
The study Lunar exploration architecture—deployable structures for a lunar base was performed within the Alcatel Alenia Space “Lunar Exploration Architecture” study for the European Space Agency. The purpose of the study was to investigate bionic concepts applicable to deployable structures and to interpret the findings for possible implementation concepts. The study aimed at finding innovative solutions for deployment possibilities. Translating folding/unfolding principles from nature, candidate geometries were developed and researched using models, drawings and visualisations. The use of materials, joints between structural elements and construction details were investigated for these conceptual approaches. Reference scenarios were used to identify the technical and environmental conditions, which served as design drivers. Mechanical issues and the investigation of deployment processes narrowed the selection down to six chosen concepts. Their applicability was evaluated at a conceptual stage in relation to the timescale of the mission.