Lunar Structures Research Articles

Rapid formation of high-performance lunar regolith composite via combined mold pressing and thermocuring processing with low content of resin-based additives

Establishing lunar bases is pivotal for furthering lunar research and propelling deep space exploration. Lunar regolith based in-site construction is identified as the most feasible method for lunar structures. In addition, the reliance on Earth-Moon transportation, the energy required for lunar regolith manufacturing and the quality of the fabricated products are key factors in choosing a suitable forming method. This study proposes a novel way for in-site lunar regolith construction by utilizing a small amount of resin-based binding material and a combined processing method of molding and thermosetting. A specific thermosetting resin is developed to achieve fully solidification of the mixed material at lunar daytime temperatures of approximately 120 °C, addressing the high energy consumption associated with the sintering process. Mold pressing is used to provide the rapid pre-forming of mixed materials and greatly reduce the proportion of additives. The binder additions ranging from 5 wt% to 1 wt% were investigated. It was found that the formed part with a binder proportion of 2 wt% could achieve a compressive strength exceeding 26 MPa and the low thermal conductivity of about 0.371 W/(m·K). The proposed method has advantages of high in-situ utilization rate, low-energy consumption and rapid formation rate, enabling efficient forming of high performance lunar regolith structure and providing feasibility for future lunar construction projects.

Influence of vacuum and high-temperature on the evolution of mechanical strength and microstructure of alkali-activated lunar regolith simulant

Alkali-activated lunar regolith (AALR) has become one of the most promising lunar building materials, offering the potential to support the construction of large-scale lunar structures. This paper presents a comprehensive experimental investigation on the fresh properties, physical properties, mechanical performance and microstructural characteristics of alkali-activated lunar regolith simulant (AALRS) considering the effects of lunar environments (high-temperature, vacuum and coupled high-temperature and vacuum), alkaline activators (sodium hydroxide and sodium silicate) and curing age. The results show that AALRS under high-temperature environment exhibits higher strength while the strength development is limited. However, AALRS under vacuum environment exhibits lower strength but the strength increases as the curing time increases. In terms of pore structure, the volume fractions of macro voids for SH-V and SS-V account for up to 50.94 % and 63.64 %, respectively, which are 12.22 % and 7.95 % higher than those of SH-H and SS-H. Regarding the impact of coupled high-temperature and vacuum environment, the compressive strength of SH-HV-7 is reduced by 47.8 % compared to that of SH-H-7, while the compressive strength of SS-HV-7 exhibits a 57.2 % increase over that of SS-H-7. The sodium hydroxide-activated (SH-activated) system and sodium silicate-activated (SS-activated) system demonstrate fundamentally intrinsic differences in terms of reaction products, structure build-up and pore structure. The positive optimization mechanism and reverse degradation effect of vacuum environment on the performance of AALRS paste were revealed. Finally, the evolution of structural characteristics of AALRS paste under different environments was elucidated.

Determining Peak Shock Pressure and Cratering due to Hypervelocity Meteoroid Impact on Lunar Structures for Engineering Design

Determining Peak Shock Pressure and Cratering due to Hypervelocity Meteoroid Impact on Lunar Structures for Engineering Design

Establishing Standards for Lunar In Situ Resource Utilization Structural Materials

Lunar structures will be exposed to one of the most extreme environments that have ever been considered for human settlements. In situ, regolith-based materials are being proposed for construction on the moon, offering the benefit of reducing the cost of transporting large amounts of materials or prefabricated elements, and relying on the ability to transport mainly the equipment needed to construct landing pads, shelters, blast shields, habitats, roadways, etc. However, the properties of materials that are made, all or in part, from indigenous lunar resources are likely to change based on the make-up of the material, the location where it was taken from, the production processes, and time. No standards or building codes exist for the design and construction of infrastructure on the moon. Engineers will need dependable information about these materials before any design can be completed. Hard-won lessons from centuries of using similar resources on Earth need to be leveraged to develop the best procedures that will be critical for testing such materials for structural applications. Here we discuss the technical challenges of establishing such standards. Using the timely example of a landing pad on the moon, we identify the gaps in both knowledge and testing capabilities that exist today.

Seismic assessment of a long-term lunar habitat

The establishment of secure earth-independent long-term lunar habitats has been envisioned by numerous government agencies and private companies. Recent advancements in assessing seismic hazards caused by shallow moonquakes have highlighted the importance of incorporating this phenomenon into the design of robust and resilient lunar structures. However, further research is required to explore lunar habitat design that considers seismic loads. This paper proposes assessing the structural response of a lunar habitat made of sulfur concrete covered with a regolith layer. The numerical model of the structure is subjected to gravitational, internal pressure and seismic loads. The seismic analysis of the structure is carried out using spectral and nonlinear time history methods. Conditional mean spectra for shallow moonquakes with return periods of 75, 475, 970 and 2475 years are used in the seismic analysis. The records used for the temporal analyses were ground motions that agree with a preliminary seismic hazard on the Moon. The results of temporal analyses reveal that shallow moonquakes with return periods greater than 475 years can lead to the loss of the global stability of the structure. Consequently, the findings imply that seismic loads have the potential to impose unacceptable demands on lunar structures constructed from in-situ materials like sulfur concrete. Hence, it is imperative to incorporate seismic considerations in the design process for developing resilient and long-term lunar habitats.

Mechanical design of a lunar habitat structure and deployment mechanism

With NASA's Artemis program currently underway, the necessity to have lunar structures that can house astronauts for months at a time is now greater than ever. This paper investigates current deployable lunar habitat concepts and finds a paucity of detailed papers in the literature. The hybrid deployable lunar habitat architecture considered here went through many design iterations to simplify and support its manufacturing. A novel deployment mechanism is developed utilizing the release of pressurized gas for an autonomous deployment sequence. A prototype was fabricated that demonstrated a successful proof of concept, leaving a robust foundation for future research.

The decorative structure in the calligraphic painting

The decoration structure in calligraphy painting is one of the variables that characterized the structure of the calligraphic composition due to the artistic, aesthetic and expressive properties of the letters of the Arabic calligraphy, which are represented by flexibility, compliance and the ability to form. Therefore, the researcher defined his problem by asking the following question: What is the decorative structure in the calligraphic painting? The study aimed to reveal the structure of the ornamentation in the calligraphy painting, while the researcher dealt with in the second chapter three sections, the first (the ornamental concept and meaning) and the second topic (the structural characteristics of the Arabic letter in the calligraphic calligraphy painting) and the third topic (the aesthetic foundations in the calligraphic calligraphy painting) and then Indicators of the theoretical framework and previous studies, while the third chapter dealt with the research procedures, where the researcher adopted the descriptive analytical approach of the research community and sampled it by 10%. (The ability of the Arabic letter and its response to formation contributed by employing it to produce calligraphic lettering paintings with lunar structures) and then recommendations to benefit from the results and findings of the research to support researchers, scholars and specialized colleges, and the researcher suggested a study (the formal significance of the trapping effect in the lettering calligraphy painting).

Study on low gravity effect on bearing capacity and slope stability of a new lunar highland soil simulant (LSS-ISAC-1) for futuristic moon habitation

The future lunar missions of the space research organizations (SRO) such as the (US) National Aeronautics and Space Administration (NASA), the China National Space Administration (CNSA), the European Space Agency (ESA), the Indian Space Research Organisation (ISRO), the Japan Aerospace Exploration Agency (JAXA), and the Russian Federal Space Agency (RFSA or Roscosmos), etc., comprise extended stay on Moon, making the lunar surface a launchpad for the interplanetary missions and Moon habitation. These are the most challenging task for the space research organizations (SRO) and the researchers, which needs all engineering disciplines. Also, the distinct difference in the environment between the lunar surface (lunar gravity, moonquakes, high temperature, etc.) and the Earth forced the SROs and the researchers to study the geotechnical properties such as specific gravity, particle size distribution, density, shear strength, and bearing capacity of the lunar soils. In this, the lunar gravity (1/6g) significantly influences the bearing capacity of the lunar soil, which is the predominant property for the design and analysis of foundation systems of the lunar structures. Assessing the bearing capacity under the reduced lunar gravity will enhance the evaluation of design criteria for the lunar structures and their foundation systems. In this respect, this paper explains the low gravity effect on the bearing capacity of the new lunar highland soil simulant LSS-ISAC-1 developed to represent the geotechnical properties of the highland soils of the lunar surface. The bearing capacity of the simulant for both the lunar and Earth gravity was evaluated and compared with the lunar soils and lunar simulants. The plate load test and single wheel load tests were performed to determine the sinkage property (compression/settlement) of the LSS-ISAC-1. The slope stability and self-standing height of the LSS-ISAC-1 were also determined for a better understanding of stability. Overall, the comparison results state that the new simulant LSS-ISAC-1 is more than sufficient to support virtually any conceivable structures based on the results.

Preliminary approach to assess the seismic hazard on a lunar site

The passive seismic network deployed on the Moon during the Apollo missions operated for eight years and allowed the observation of seismic activity. More than 12500 seismic events were registered, where 28 were classified as shallow moonquakes with moment magnitudes up to 4.1. Seismic events of this nature pose a significant risk to future long-term lunar habitats; thus, these events must be carefully studied and considered in the seismic design of these structures. This paper proposes a preliminary seismic hazard assessment imposed by shallow moonquakes. The hazard assessment is performed using the Probabilistic Seismic Hazard Analysis (PSHA) methodology, considering previous studies and theories regarding the seismic environment of the Moon. The study zone covers ∼860 km2 of the Taurus-Littrow Valley, containing the Apollo 17 landing site and the Lee-Lincoln lobate scarp as the considered seismic source. The seismic hazard is quantified in terms of peak ground acceleration (PGA) and spectral acceleration (5% damped pseudo-acceleration, PSA). Seismic hazard deaggregation scenarios, Uniform Hazard Spectra (UHS) for different hazard levels, and a Conditional Mean Spectrum (CMS) for a target period of 0.2 s are obtained to quantify the seismic hazard on a specific site on the Moon. The developed seismic hazard assessment provides a preliminary approach for realistic scenarios to conduct structural designs that ensure the seismic performance of fully operational long-term lunar structures.

Assessment of dynamic properties of a new lunar highland soil simulant (LSS-ISAC-1) developed for Chandrayaan missions

The distinct difference between the lunar surface (Moon) and the Earth forced space research organizations (SRO) and researchers to study the geotechnical properties of the lunar soils for the successful execution of lunar missions. The planned Chandrayaan Missions of the Indian Space Research Organization include constructing lunar structures on the lunar surface for the future Moon colonization. The stability of such lunar structures is completely dependent upon the foundation systems adopted. The foundation systems of these lunar structures are expected to encounter various types of vibrations due to moonquakes on the lunar surface. The analysis and design of a foundation system with respect to ground motion and vibration rely on the dynamic properties of the lunar soil. Also, the characterization of dynamic soil properties like shear modulus, damping ratio, and Poisson's ratio is essential for the safe design of foundation systems. Therefore, it is imperative to evaluate the dynamic properties of the lunar soil against moonquake-induced vibrations. Past research has utilized lunar soil simulants were used to assess the lunar soil's geotechnical properties. In that order, this study explains the dynamic properties of the new lunar highland simulant LSS-ISAC-1 under simulated moonquake conditions using cyclic triaxial tests. The shear modulus and damping ratio were determined from the cyclic triaxial tests for the different relative densities (30%, 63%, and 80%), confining pressures (5 kPa–75 kPa), and frequencies to represent the loose, medium, and dense states of the lunar surface. The bender element test is also done to find the shear wave velocity and maximum shear modulus. The results were compared with the lunar soil simulant CAS-1 and lunar soils to show the reliability of the obtained test results of LSS-ISAC-1. • A new lunar highland soil simulant (LSS-ISAC-1) was developed by ISRO using terrestrial anorthosite rocks to mimic the geotechnical properties of the highland soils of the lunar surface. • Dynamic properties of the LSS-ISAC-1 were determined using the cyclic triaxial test. • The measured dynamic properties would be considered for proposing a suitable foundation system for lunar structures considering the Moonquake effects. • Test results were compared with the actual lunar soil and lunar soil simulant CAS-1 to show the reliability of the obtained test results of LSS-ISAC-1.

A new deployable pantographic lunar habitat

Deployable lunar structures have been and are being developed as an appropriate solution to the volumetric limitations of cargo mission flights. A deployable lunar habitat consisting of linear and planar elements connected through simple movable joints is introduced. This new structure is made of some linear units consisting of two types of scissor-like elements (SLE): 1) a modified polar scissor-like element and 2) a closed-loop of angulated scissor-like elements. After conducting theoretical research on lunar habitats, the evaluation criteria of transformable lunar structures are derived and then many new concepts are evaluated. The design considerations of such structures are discussed, and a proper form for these habitat types is selected. An experimental study is run to assess the best deployment strategy for the whole structure. By introducing the dimensional properties of the lunar habitats through physical and digital modeling process per crewmember, the derived alternatives from the previous stage are analyzed and the best transformation strategy that meets the aforementioned considerations is developed. Providing relatively high degrees of protection against environmental hazards through the combination of rigid plates with membrane, this proposed structure reduces the required extravehicular activity (EVA) time for assembly because of its quick and simple deployment mechanism. The folded state of the structure provides a low volume for the integration of subsystems.

Remarks On The Sources Of Error In The Modelling Of Lunar Geotechnical Structures

Abstract Scale modelling should be a very useful strategy for the design of lunar structures. Preventing structural damages in the lunar environment is crucial and scale models are helpful to achieve this aim. The size of these models must be scaled to take into account the different gravitational levels. Since the lunar gravity acceleration is about one-sixth of the terrestrial one, it follows that the models on Earth will be very smaller than the prototype to be realized on the Moon. This strategy will represent an opportunity for engineers working on lunar structure design, provided that the errors, both computational and experimental, related to the change of scale are quantified, allowing reliable extension of the physical scale modelling results to the prototype. In this work, a three-dimensional finite element analysis of walls retaining lunar regolith backfill is described and discussed, in order to provide preliminary results, which can guide a future experimental investigation based on physical scale-modelling. In particular, computational errors related to the scale effects are assessed, with respect to a virtual prototype of the lunar geotechnical structure, and compared with errors from other sources of discrepancy, like the adopted constitutive model, the variability of the geotechnical parameters and the calculation section used in the 3D analysis. The results seem to suggest the soundness of this strategy of modelling and are likely to encourage new research, both numerical and experimental, supporting the structure serviceability assessment.

Improved Views of the Moon in the Early Twenty First Century: A Review

The twenty first century was an exciting epoch in planetary exploration, when a large number of lunar scientific achievements were accomplished. New missions in the first decade of the twenty first century have herald a new and exciting phase in lunar exploration, including LRO, LCROSS, the dual GRAIL orbiters, Kaguya, Chandrayaan 1, and the Chang’e series. Here we review the most significant advances in our understanding of lunar geoscience, including the assessment of water ice at lunar poles, the detection of new elements and minerals relating to exposed interior materials, the calculation of highly accurate gravity models, and the detection of subsurface interfaces probably related to basaltic strata formed in distinct episodes. In this paper we emphasize the importance of integrated approaches to the analysis of these large yield of new lunar data, through comparison and integration. By integrating a range of diverse technologies and approaches, this paper reviews new understanding of lunar processes, including the confirmation of the presence of water ice at the poles, the interactions between solar wind and surface oxides, and an improved model of lunar interior structures.

Multiple waves and the lunar core

The model of the internal structure of the Moon with "open" deep faults and weak contacts between sides for many lunar regions explains the existence of a block structure (1-3). A high seismic Qfactor of lunar structures and significant impact energy (~10 19 erg) produced by the fall of a large meteorite led to formation of multiple waves on the major internal lunar boundaries. The known statistical methods have allowed us to determine the vibration periods for these waves and, hence, to define the internal lunar struc� ture, including the central zone (core). Let us consider the manifestation of a block struc� ture in different portions of an impact seismogram and the influence of the block structure on wave propaga� tion in more detail. We also discovered some seismic effects that had previously been observed on the Earth. The peculiarities of lunar geological structures and waveforms of seismograms became the prerequisites and evidence for the existence of a high modulation

Magnesium as an ISRU-Derived Resource for Lunar Structures

AbstractMagnesium is one of the most pervasive metals in lunar soil and has many characteristics that make it applicable to in situ refining and production. This somewhat overlooked alkaline earth metal is easily cast, used, and recycled, characteristics that are required in the Moon's harsh environment. Moreover, alloys of this element have several properties fine-tuned for building shelters in a lunar environment, including several advantages over aluminum alloys. Magnesium alloys may prove to be the optimal choices for reinforcing lunar structures or manufacturing components as needed on the Moon. As such, further research on the in situ resource utilization (ISRU) of magnesium is imperative for the development of a self-sufficient lunar base. This paper brings together key properties of magnesium within the context of it being used as an in situ resource once the Moon, again, becomes a goal for permanent habitation and we require the ability to live there in perpetuity.

Soil Simulations May Simplify Design Of Lunar Structures

Engineers have developed a digital method for predicting soilstructure interaction that could improve construction in remote locations—including the moon.

Technical Requirements for Lunar Structures

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 w...

Lunar base design: a paradigm for the capstone design course

Most engineering programs have a capstone design course, as per the Accreditation Board for Engineering and Technology (ABET) requirements, the recognized US accreditor of college and university programs in applied science, computing, engineering, and technology. This paper proposes that such a course be placed in a larger and coupled design framework, that is, that all student design groups choose or be assigned a project that considers some aspects of the design of a lunar surface structure intended for human habitation. The senior mechanical and aerospace engineering capstone design course is a two-semester six credit course sequence that is intended to expose each graduating engineering student to the full spectrum of engineering experience. A review is given of the essentials of lunar surface structures design. Example project areas are given

¿El fraude del siglo?

Tiempo después comenzaría una polémica que alteraría este evento mundial: ¡Se Acusaba a la NASA de fraude!. Las fotografías tomadas por las misiones Apolo, los paseos lunares y algunos accidentes técnicos anteriores a la primera misión coronada con éxito contienen "anomalías" que han sido descubiertas por expertos en fotografía e investigadores. Existen dos teorías sobre este particular. Una se apoya sobre la hipótesis de un fraude total, es decir, jamás el hombre pisó la luna y fuimos engañados a una escala nunca vista por la humanidad, debido a que sólo fue una propaganda para demostrar su poderío frente a la ex Unión Soviética. La otra teoría, tan creíble como la anterior, indica que el hombre sí estuvo en la Luna, pero varias fotografías fueron realizadas en estudios de la Tierra, debido a que las originales contenían ovnis y estructuras lunares extraterrestres. Se dice que los astronautas estuvieron vigilados allí por ovnis y que usaron un canal de radiocomunicación secreto para coordinar acciones con la base en Tierra.

Atmospheric Pressure within Lunar Structure

Design and construction of a structure on the Moon requires addressing a host of issues not encountered on Earth. Since there is no atmosphere on the Moon, a lunar structure must contain an artificial atmosphere. One critical design issue is the magnitude of the pressure of this atmosphere. Much of the current literature on the design of lunar structures assumes a pressure of 101.3 kPa (14.7 psi), corresponding to that at sea level on Earth, which is an order of magnitude larger than any other loading on the structure. An assessment of the outcome of lowering the internal pressure for a lunar structure is presented that accounts for human physiology, plant growth, mechanical equipment for gas circulation, structural aspects, leak rate, decompression, flammability, combustion, and economic issues. Options for the magnitude and content of an internal atmosphere for a lunar structure are given. Results clearly show that there is a great savings if the pressure is lowered by an amount that does not greatly affect the inhabitants physiology or safety.