Earth and Space 2022: Space Exploration, Utilization, Engineering, and Construction in Extreme Environments

Any Martian mission entailing establishment of a habitat or vehicles operating on planetary surfaces requires proper characterization of native soils. Planetary geology along with regolith properties greatly influence the construction parameters, such as excavation mechanisms, and mechanical interactions between structures and the regolith platform. The primary objective of this research was to mechanistically characterize the physical and mechanical properties of the JSC Mars-1 regolith simulants to better understand the physical, mechanical, and physio-chemical properties of the native soils and its relevance to planetary construction. To achieve these objectives, a comprehensive experiment matrix was devised to simulate the compaction characteristics of unbound particulate materials in the laboratory. The resilient properties, strength parameters, and deformation potential were of primary interest in this effort. Additionally, the strength and deformation potential of the JSC-1 Martian simulants were contrasted with a conventional terrestrial construction material for comparative purposes. The study also investigated the contribution of the magnitude and method of application of the compaction energy on the dilatancy behavior of particulate materials in the laboratory. The laboratory results showed appreciable strain rate dependency of the strength parameters for simulants at multiple relative compaction levels. This underscores the significance of nonlinear and anisotropic regolith modeling for proper determination of orthogonal strength characteristics, settlement potential, and stability of platforms for planetary construction.

It is necessary to determine fallout locations of regolith ejecta from descent engine plume-surface interactions due to the risks such particles present to lunar surface operations. Models of ejecta trajectories demonstrate that regolith fallout could reach anywhere on the lunar surface. However, these models have yet to consider the topography of the lunar surface that can modify trajectories to either extend or reduce the range of ejecta. Here we couple orbital-based trajectory modeling with the lunar digital elevation models from LRO/LOLA to determine fallout locations around potential landing sites in the region of the lunar south pole. Limited particle trajectories have been matched to the lunar topography at a spatial resolution of 5-m. We demonstrate lunar topography can both prevent ejecta leaving landing site locations and vary impact locations by over 100%. Thus, lunar topography must play a role in quantifying the risks of ejecta from a chosen landing site.

In the next decade, NASA is prioritizing Moon missions such as safe human transportation, deployment of instrumentations, establishment of habitats, and exploration of native resources to set the stage for future Mars missions. One of the main challenges to achieve these goals, however, is our lack of understanding of the synergistic interactions between the native soil, lunar vehicles, habitats, and EVA suits. In addition to the particle size distributions, surface properties, and compaction characteristics of the surface regolith, the geometry of the particles is of paramount importance for a proper understanding of the settlement properties, distortion characteristics, and orthogonal strength of the particulate medium, which impacts transportation, habitat development, and the regolith’s potential to degrade EVA suits by abrasion based on the angularity of the particles. Therefore, our multi-disciplinary team in this research envisioned using a state of the art optical profilometer equipment supplemented by image analysis techniques to characterize the geometrical features of a lunar regolith simulant, specifically the CSM-LHT-1 highlands type. The distributions of the particle form, angularity, and surface macro-texture of lunar regolith were in turn contrasted with JSC-1 Mars simulants and a calcareous construction aggregate for comparative purposes in this study. The results will be instrumental to better understand the anisotropic nature of the angular particles and its relevance to the strength and deformation characteristics of native soils on extra-terrestrial planetary surfaces.

Traversing granular regolith, especially in reduced gravity environments, remains a potential challenge for wheeled rovers. Mitigating hazards for planetary exploration rovers requires testing in representative environments, but direct Earth-based testing fails to account for the effect of reduced gravity on the soil itself. Granular scaling laws (GSL) have been proposed in the literature to predict performance of a larger wheel based on tests with a smaller wheel, or to predict performance in one gravity level based on tests in another gravity level. Recent experimental results by the authors suggest that GSL offers an accurate and conservative method for predicting wheel performance in reduced gravity based on 1-g experiments, at least in cohesionless soil. For cohesive soils, an additional constraint has been proposed in the literature stating that the radius ratio must be the inverse of the gravity ratio. For example, to predict wheel performance in lunar-g based on 1-g tests, the wheel radius in 1-g must be 1/6 of the wheel radius in lunar-g (since the gravity on Earth is 6× higher than lunar gravity). To date, this has only been validated using numerical simulations. This work considers this proposed GSL cohesion constraint for lunar regolith, which is estimated to be mildly cohesive (0.1–1 kPa). Testing a 1/6-scaled lunar rover may not be practical or desirable, so the error introduced by ignoring this cohesion constraint should be quantified. To evaluate this cohesion constraint, preliminary experiments have been performed measuring performance of single wheels of different radii driving through the lunar soil simulant LMS-1, which has cohesion similar to the estimated cohesion of lunar regolith. Results obtained using these wheels will later be compared to experiments with a larger wheel on parabolic flights producing effective lunar gravity. The two wheels tested in 1-g have radii equal to 1/6 and 1/2 of the radius of the wheel that will be flown in lunar-g. Applying GSL to preliminary results from these two wheels, dimensionless drawbar pull (i.e., net traction), sinkage, and power draw were calculated. Since tests with the 1/6-radius wheel followed the cohesion constraint and tests with the 1/2-radius wheel did not, the error introduced by ignoring this constraint can be estimated based on the difference between the dimensionless results from tests with each wheel. Results were similar (i.e., not statistically significantly different) for the two wheels, which suggests that ignoring the cohesion constraint may not have a significant effect for the low levels of cohesion present in lunar regolith. However, drawbar pull was negative for both wheels at all slips tested, indicating that the thrust generated by the wheel was lower than the resistance. Future experiments will be performed in different conditions that generate positive drawbar pull to make a more conclusive comparison, in addition to the planned lunar-g experiments.

Future missions to the Moon will require mechanisms and materials to effectively and reliably operate in the presences of lunar regolith. One of the challenges of developing such technologies is terrestrial testing with lunar dust simulants. Dust has a stochastic nature of depositing and it can be difficult to accurately apply it to surfaces of interest. Deposition density, particles size distribution, and percent coverage are all factors that affect the quality of dust mitigation testing. Therefore, to enable such testing the dust mitigation and seals teams at NASA Glenn Research Center (GRC) have developed a system that can uniformly and repeatably deposit lunar simulants on a range of surfaces. Testing of the dust deposition system (DDS) and an associated simulant preparation methodology have quantified the levels of uniformity and precision for this system. Furthermore, the deposition system has been paired with automated micrograph capturing and machine learning image analysis to correlate the images of dust on a surface to deposition density (in g/cm²). This correlation alleviates the need for tested samples to be accurately weighed with milligram precision and may be a useful tool for in situ contamination evaluation on the Moon. This paper covers the design and validation testing for the DDS.

Plume-surface interaction (PSI) between lander engine plumes and regolith soil creates hazards in obscuration and contamination by particle clouds, high-energy ejecta streams, and landing area cratering damage. The gas-granular flow solver (GGFS) enables coupled gas-particle two-phase flow simulations to predict the range of PSI effects from onset of surface erosion to deep crater formation. GGFS features an Eulerian-Eulerian modeling approach, treating both gas and granular material as interacting continuum phases. Eulerian granular material flow modeling requires closure formulations for the granular material constitutive models (stress, friction, collisional and kinetic energy dissipation, drag, etc.). Modeling the lunar regolith granular characteristics poses special challenges due to complex particle shapes and mixture composition. The integration and maturation of the constitutive model database generation process into the GGFS simulation framework are proceeding under funding by the NASA Game Changing Development program. The status of current capabilities in modeling particle shape and mixture effects is presented in comparisons of crater characteristics predicted in Apollo LM plume-surface interaction simulations.

Lunar exploration activities and infrastructure development demand well-constrained information about the geotechnical properties of lunar regolith. Since returned lunar regolith is too scientifically precious to allocate for large-scale geotechnical studies, terrestrial materials must be used to create regolith simulants that reproduce the properties of lunar regolith. Studies that use inappropriate simulants to develop lunar systems are invalid and give misleading results, but as shown here, the lunar highlands simulant produced by Exolith Lab, called LHS-1, maintains high geotechnical fidelity to highlands regolith samples. This study compares the particle size distribution, specific gravity, density, and shear strength of LHS-1 simulant with two different preparation methods: ambient storage and oven dried.

Lunar dust is a known hazard to further surface exploration of the Moon. Due to the jagged shape of lunar dust particles and the small particle size, lunar dust poses serious danger to astronauts and equipment sent to the surface of the Moon. To develop dust mitigation solutions, a high-fidelity regolith analog is required in a particle size relevant to dust applications. Exolith Lab developed lunar highlands dust simulant (LHS-1D) and lunar mare dust simulant (LMS-1D) as analogs to test ISRU dust solutions. Both LHS-1D and LMS-1D are made from the same mineral recipe as their parent simulants. This allows them to accurately replicate the chemical composition and mineralogy of lunar regolith. They are processed to be extra-fine, which makes them ideal for lunar dust applications studies.

The interlock drive system generates traction by inserting narrow articulated spikes into the ground and by leveraging the soil’s strength to resist horizontal draft forces. The system promises high tractive performance in low gravity environments where tires have little traction for lack of weight. At Earth and Space 2021 we reported the performance of such spikes on a silty clay loam, a cohesive soil. We found that in such soil, traction below a critical depth is provided by a zone of lateral soil failure. We also found that the articulation translates a horizontal draft force into a vertical penetration force strong enough to penetrate a narrow spike to a depth where the soil can sustain the draft force, in a self-regulating way. It is conceivable that a granular material like regolith or sand with little to no cohesive strength provides less vertical penetration resistance and less resistance to a horizontal draft force than a cohesive soil, which leads to the question of whether and how much tractive force an interlocking spike can generate on a granular material. Here we report on field trials that study different spike designs in dry and unsaturated moist sand. The results demonstrate that a loose granular material requires larger spikes than a cohesive soil, that these larger spikes penetrate dry and moist sand reliably, and that they promise good tractive efficiency. The trials indicate that on sand, a larger spike diameter can improve the pull/weight ratio without a loss of tractive performance.

The handling and transportation of rocky unconsolidated material (regolith) on celestial bodies, such as the lunar surface, is an important step for its utilization as a resource to meet manufacturing needs and achieve a sustained human presence on these bodies. Lunar regolith is considered a feedstock that must be delivered to processing reactors, like a molten regolith electrolysis (MRE) reactor, either as is or beneficiated prior to its transformation into usable commodities. The transportation of lunar regolith is difficult as it does not flow well, is abrasive, and can cause significant wear to parts and surfaces over long exposure periods. 110-H02 copper, 304 stainless-steel, nonporous alumina ceramic, and 6061 aluminum were all tested to determine short term scratch wear effects caused by exposure to lunar regolith simulant. This research investigates the change lunar regolith simulant imparts on these surfaces by calculating friction coefficients before, during, and after lunar regolith simulant exposure. This kind of parameterization is novel and will help set requirements for systems exposed or transporting lunar regolith simulant on the surface of the Moon.

Understanding, mitigating, and minimizing power and mass requirements are crucial to developing the next generation excavation technologies for lunar and planetary in situ resource utilization (ISRU). Towards this end, electrical power to the advanced planetary excavator (APEX) was measured while excavating granular lunar soil simulant GRC-3B. Using a 21.6-cm wide bucket having a 30° leading edge, arc-shaped backhoe trajectories were dug to depths of 5, 10, and 20 cm with rake angles of 10, 20, and 30 degrees. Maximum net power, net energy, net energy per mass excavated, rate of mass excavated, horizontal distance from soil entry to exit (at bucket tip), and the trajectory to bucket volume percentage are presented to inform the scientific community as trajectories and designs are planned for future missions. Using APEX’s capability to evaluate power and energy consumption of excavation tools and processes gives guidance to developing power requirements and efficient methods for lunar excavation.

The lunar surface is covered with dusty regolith with mixed minerals down to a well-known depth. The minerals have different physical and chemical properties and cannot be treated in bulk. It is important that we understand the properties of major components in the regolith. During lunar landings there will be a large amount of surface erosion and scouring due to plume-surface interaction. The ejected material can damage the instruments within reach. A proposed solution is to construct a landing pad, and a leading method is microwave sintering. The measured magnetic susceptibilities of lunar minerals are found to fall under three distinct ranges which facilitates magnetic beneficiation. We find that higher magnetic susceptibility correlates higher microwave susceptibility. This allowed us to investigate microwave sintering by using the magnetic portion as an energy trap and nonmagnetic portion as a wall. Results from the experiments with variations of these mechanical heat trap systems show that we can achieve deep reduction in the energy and thus also the time and cost of sintering the lunar landing pad.

The sample acquisition, morphology filtering, and probing of lunar regolith (SAMPLR) payload is a robotic arm and instrument suite that are manifested on Masten Mission One, the commercial lunar payload services (CLPS) mission slated to fly to the south pole of the Moon in November of 2023. SAMPLR is a collaboration between Maxar Technologies, NASA's Goddard Spaceflight Center, and the Colorado School of Mines Center for Space Resources as part of NASA's lunar science and instrument technology payload (LSITP) program. One of the instruments in the SAMPLR suite is a specialized penetrometer. This specialized penetrometer is a lightweight and relatively simple instrument that provides a large amount of useful in situ geotechnical data. The SAMPLR penetrometer will be used to aid in the determination of geotechnical properties and the characterization of lunar regolith. The penetrometer can also assist in identifying the presence and concentration of ice in lunar regolith. A catalog of specialized penetrometer data is being developed at the Colorado School of Mines in support of the SAMPLR mission. This paper will provide an overview of the specialized penetrometer instrument on the SAMPLR mission along with penetrometer operations, data analysis, and representational results.

Understanding the responses of lunar regolith during the drilling process in a low gravity environment is an important problem for geotechnical engineering in the realm of space exploration. Evaluation of the in situ physical and mechanical properties of lunar regolith will be essential for the development of in situ resource utilization (ISRU) capabilities as well as the construction of a permanent base on the Moon. However, due to limited access to the low gravity environment on the lunar surface, it is difficult to perform physical model tests to simulate the drilling process into the lunar regolith (or its simulants). The discrete element modeling (DEM) provides a useful numerical tool to investigate the behavior of the lunar regolith during the drilling process. This paper presents a discrete element modeling of drill-regolith interaction to evaluate the regolith behavior during the drill penetration process under the simulated lunar environment. The contact parameters for the discrete element modeling are calibrated using the triaxial testing results from lunar regolith simulants of JSC-1A. The responses during the drilling process such as tip and frictional resistance are monitored to evaluate the change of mechanical properties of the lunar regolith simulants with the depth.

The accumulation of lunar dust on various surfaces is the subject of much recent study, yet is still poorly understood. Recent plans to return humans to the Moon as part of the Artemis program mean that the presence of robust infrastructure to support a permanent human presence is inevitable. Power supply systems, such as radioisotope thermoelectric generators are a likely part of that infrastructure, but require radiative thermal dissipation through a series of radiator fins to function effectively. In this work, the results of a parametric study of the impact on radiator efficiency due to various quantities and types of lunar dust simulants are presented, determining that the impact from low levels of lunar dust accumulation is not significantly detrimental to the efficiency of multi-mission radioisotope thermoelectric generator performance in a vacuum, but increased fidelity of data would improve these findings.

Due to payload limitations in space missions, light and compact investigation tools should be developed for subsurface exploration on the Moon, Mars, and beyond. Here, we aim to investigate the effects of high-frequency vibrations on reducing the overhead load required for the penetration of a typical probe into granular media. The discrete element method is used to examine the effect of vibration frequency, mode, and the probe's head on penetration resistance. The results show that employing high-frequency vibration is a promising technique for overcoming the payload limitations for subsurface investigation in remote areas.

Detailed characterization of the subsurface properties of in situ planetary regolith is critical to many applied areas in planetary science, astrobiology, space engineering, and to the operational success of all future science missions involving surface or near-surface contact. Understanding the geomechanical properties of planetary regolith, as well as determining the presence and the chemical potentials of liquid water and water-ice, are both central to NASA’s exploration strategy for future manned long-term exploration of the Moon and Mars. SPARTA (Regolith Properties Assessment, Resistance, Thermal, Analysis) is a highly versatile, miniature toolkit that provides NASA with a new capability for in situ measurements of mechanical, thermal, electrical, and chemical properties of dry or icy regolith and permafrost during surface-landed missions. SPARTA is designed for planetary bodies such as the Moon, Mars, Mercury, Venus, asteroids, and comets with or without atmospheres, that may/may not contain water/ice.

In situ resource utilization (ISRU) has become an important topic in space exploration. To become sustainable on the Moon, ISRU should be established to provide the necessary material to build structures that will sustain life. In order to begin this continuous presence stay on the Moon, landing pads must be designed and built in order to transport autonomous vehicles and equipment to the lunar surface due to the larger SLS or Star Ship platforms used in Artemis compared to the much lighter Apollo lunar landers. The focus of this abstract will be addressing the strengths and weaknesses of the sintered basalt building block prototype developed at the Pacific International Space Center for Exploration Systems (PISCES) and providing recommendations or solutions to improve it for landing pad use. In a 2018 study conducted at PISCES, a new type of building block was designed from regolith feedstock. This building block was designed for foundations and infrastructure, but more importantly for landing pads. The testing conducted on the lunar building blocks was determined to be able to withstand “the high velocity and high temperature of a solid fuel rocket motor”. The interlocking design did cause the basalt blocks to crack and separate during the rocket test. There are many strengths and weaknesses from this study that will be analyzed in the following report. Additionally, recommendations on improving the basalt block will be taken into consideration for future design improvements and testing. While this block design and recommendations are a possible solution to the landing pad question on the Moon, further research and testing will need to be completed to ensure the safety and durability of future designs. Implementing these recommendations for improvement with the lunar material acquired through ISRU could potentially be the future of landing pads on the Moon and beyond.

We explore several facets of lunar rovers relevant to the conduct of lunar mining. In particular, we suggest that subsurface mining for asteroidal material shall be necessary. Our end-to-end 30 kg Kapvik microrover prototype has served as a testbed for exploring these issues—terramechanics, vision, SLAM, path planning, onboard intelligence, and multi-rover deployment. We suggest that microrovers are fully functionally capable platforms for lunar ISRU, especially if employed as cooperative fleets.

In this work, a co-simulation framework using commercially available software ADAMS for multi-body dynamics models and EDEM for discrete element models is developed for simulating the mechanical behavior and mechanical motion of regolith-tool interaction. The co-simulation tool is first evaluated and verified using simplified motion systems, where experimental data and/or analytical solutions are available. Sensitivity analysis is conducted to understand the effect of model parameters such as time step ratios on system response. The developed co-simulation framework is then applied to simulate a target lunar regolith-drill system to demonstrate its potential in regolith-tool interaction modeling. This new co-simulation framework will provide a more accurate, two-way coupled model, to predict tool behavior with lunar and Martian regolith for sampling or drilling instruments. In addition, this research will lay the groundwork for modeling more complex systems for planetary exploration missions.

Since the 1980s, technology advances have taken drilling diagnostics systems from offline rule-based expert-systems drilling advisors to real-time drilling and sampling automation and control systems capable of standalone prospecting and subsurface sampling in planetary missions. As an example of the latter, the recent ARADS project demonstrated autonomous drilling and health management from a rover at a terrestrial analog site. In this paper we discuss inverting or repurposing the ARADS drilling control and onboard diagnostics to create a drilling advisory console tool, with the intent of improving situational awareness and subsurface feature recognition in support of science mission operations.

As space exploration expands to include human expeditions to the surfaces of other planetary bodies, sustainable in situ resource utilization (ISRU) infrastructures to harvest local resources for water, building materials, and propellants must be developed. Water is the most critical component in the near-term and is therefore the focus of many studies. However, being able to extract other resources with the same system will have long-term flow-on benefits. Ablating surface material using electric arcs creates free ionized particles that can be sorted by mass into material groups and transported to a relevant collector by electromagnetic fields. Collectors specific to each material type are used in parallel to enable maximum collection efficiencies and storage conditions for retention. The ionizing ablation arc, electromagnetic transport and sorting, and collector modules are housed within a mobile surface crawler, potentially leading to diverse and efficient ISRU for human space exploration.

Bucket ladder excavation systems are a potential solution on the Moon for excavation of granular or lightly cemented regolith for the purpose of in situ resource utilization (ISRU), construction, and subsurface science applications. This type of mechanism can continuously excavate and transport material at high excavation rate and low power use. However, there are more potential mechanical failure points in bucket ladders mechanisms when compared to other excavation systems for the Moon. Bucket ladders are the most popular excavation mechanism for the NASA Lunabotics mining competition and all winners have used a version of the bucket ladder. Previous testing of lunar bucket ladder prototypes has shown excavation rates larger than 1,000 kg/hr at a 0.01 W/kg/hr power level in atmospheric testing, but more information is required to understand the behaviour of complex excavation mechanisms under realistic lunar environmental conditions and using lunar regolith simulants. This research effort focuses on raising the technology readiness level (TRL) of bucket ladders to TRL-5/6 for lunar applications. A bucket ladder built in the Planetary Surface Technology Development Lab (PSTDL) at Michigan Technological University (MTU) is tested in a dusty thermal vacuum chamber at MTU to assess performance during extended operations. Wear on components, excavation forces, excavation rate, and power consumption are monitored. This paper will describe the bucket ladder excavation system, test setup, and preliminary results of this ongoing project. Collected test data will provide insight to the efficacy of using bucket ladders for lunar construction and ISRU as well as explore wear and tear observations.

The technical feasibility of non-conventional rock breaking techniques for space mining applications was assessed using high concentrated energy sources. A continuous and pulsed ND:YAG lasers were used to melt, drill, and cut rock samples (basalt, anorthosite/granite, and breccia) using a wide range of laser parameters. When the laser energy was concentrated on a rock sample, the temperature of the rock increased, leading to the melting/vaporizing of the material. Melting of granular materials led to the formation of a glassy sheet. This solidified material, bonded by intragranular glass, is convenient for handling, transportation, and for further processing. Blocks of fused material are useful for manufacturing building materials or processing as ore to extract needed metals and gasses. The effect of different laser input energies on the microstructure and mechanical properties of the rock samples were evaluated. Preliminary results suggest that a nanosecond pulsed laser is capable of laser ablation sufficient to cut rock materials similar to those present on the lunar surface. The overall continuous laser interaction with the rock samples resulted in melting and re-solidification in localized areas. The microhardness of the melted regions resulted in significant increase compared with the unmelted regions. Both anorthosite and basalt materials resulted in glassy phase formation after solidification. However, breaking and fracturing was observed with the continuous laser interaction with the breccia rock material.

The opportunity of in situ resource utilization (ISRU) within lunar permanently shaded regions (PSRs) prompts the need for characterizing sources for excavation. The percussive heated cone penetrometer (PHCP) is an instrument being developed, through a Lunar Surface Technology Research (LuSTR) grant at Michigan Technological University (MTU) in the Planetary Surface Technology Development Lab (PSTDL), which will be able to determine the distribution of water-bearing regolith and other volatiles in PSRs. This paper explains the methodology and preliminary results of thermal profiling as well as the development of a thermal model for the PHCP that can identify the presence of volatiles in the surrounding terrain. The evaporation of various volatiles can be detected by recording the temperature as a function of time of the material surrounding the hot penetrometer and comparing the results to a dry reference material. An initial reference test setup with dry F-80 silica sand was used to determine the size of the heat-affected zone at various power levels. In two additional test series, water was then added to these sand samples to account to provide moisture levels of 5% and 10% water by weight. Temperature curves obtained from wet sand samples show plateaus due to the latent heat of vaporization, indicating the presence of water. Tests with dry, wet, and frozen lunar regolith simulant samples were then performed to refine the PHCP thermal model to provide a closer resemblance to lunar material thermal behavior. The data sets from the thermal mapping and modeling will inform the design and manufacturing of the cone penetrometer for the LuSTR project.

Ground-penetrating radar (GPR) is a powerful geophysical method that can accurately characterize contrasting material boundaries within the subsurface in nearly any environment. Compared to other geophysical methodologies, GPR offers the greatest power output versus mass ratio, making it an excellent mechanism for rover technology. Surface mining exploration rovers can be augmented with GPR technology to scan the lunar subsurface for solid water ice bodies to be used in crucial future space endeavors. GPR allows mapping material interface boundaries such as ice, rocks, or metallic objects. The Moon is expected to contain solid water ice within its perpetually dark craters. Our preliminary research is focused on the first meter of depth within the lunar regolith since that is the initial target for potential ice excavation. It is here that solid water ice is expected to exist but in a currently unknown form. Preliminary testing was done to understanding the strengths and weaknesses of the applicable GPR equipment through experimental ice burial testing at a designated testing site. An experimental testbed containing engineered lunar simulant with approximated environmental lunar conditions is planned to be used to analyze the interactions between electromagnetic radio wave propagation and solid water ice. Testing will be done with multiple GPR devices with 50, 100, 500, and 1,000 MHz antenna frequencies. GPR devices equipped with 1,000 MHz antennas are expected to offer the greatest resolution for the depth of interest. Reflection coefficients and permittivity of materials are the key variables that are being addressed before successful characterization of lunar ice bodies. The collected radargram data will be organized into a dataset to be used as a reference for future mining rover missions equipped with GPR.

The reaction of lunar minerals to water is understudied. Lunar regolith will generally show a strong reactivity to water, and if lunar minerals are dispersed in water-based liquids, significant mineral dissolution can be expected. Here it is proposed to use lunar regolith covering the Moon surface as a primary feedstock for the production of synthetic phyllosilicates. The envisioned concept suggests dispersing fine-grained regolith in water-based media, which will result in the leaching of ions from the regolith. The leached ions will be separated from the initial leaching solution, followed by precipitation of the ions under steady conditions. The resulting solids are a portfolio of synthetic clays in various polymorphs and shapes with a range of applications in ISRU. Furthermore, the suggested work can be expected to inform research work on regolith/lunar dust in contact with water, such as greenhouses, astrobiology, dust inhalation, lunar water ice, habitat construction, and more.

In this work the applicability and challenges of low-power direct additive recycling (DAR) for on-site manufacturing and repair is discussed. Specifically, this research addresses the current DAR efforts on representative lunar regolith simulants combined with aluminum alloy (AA6061) feedstock to fabricate fully dense structural components. Optical microscopy and scanning electron microscopy identified a fully dense additive deposition with regolith particles refined and dispersed throughout the aluminum matrix. Microhardness maps captured a uniform hardness gradient across the deposited material cross section, with the regolith increasing the average hardness of the deposit above that of the substrate from which the composite was built upon. This work provides an initial framework for in situ resource utilization of regolith materials to fabricate aluminum alloy metal matrix composites in austere locations.

The exploration of ocean worlds such as Europa and Enceladus supports NASA’s goal to search for life and potentially habitable regions elsewhere in the universe, and further promises to help us understand the origins, evolution, and limits of life on Earth. Over the past several years, NASA’s Planetary Science Division has funded several technology development programs to enable future surface and subsurface missions to ocean worlds. These programs include Instrument Concepts for Europa Exploration (ICEE), Concepts for Ocean worlds Life Detection Technology (COLDTech), Scientific Exploration Subsurface Access Mechanism for Europa (SESAME), Applied Information Systems Research: Autonomous Robotics Research for Ocean Worlds (AISR:ARROW), and Astrodynamics in Support of Icy Worlds Missions. Tasks selected under these programs include the development of scientific instruments including seismometers, imagers, spectrometers, and organic analyzers, and platform technologies including drills, melt probes, through-ice communications, radiation-hard electronics, and autonomy for surface operations. This paper describes the objectives of each of these programs and provides a summary of the work that has been completed or is underway in each.

Regolith is present on many extra-terrestrial bodies, and the crushed rock material it is made of contains many of the resources that are enabling for in situ resource utilization (ISRU). When extracted, these resources can be used to provide consumables such as rocket propellant, human life support, working fluids and gases for industrial processes, and feedstocks for manufacturing. In addition, the regolith can also be very beneficial for construction purposes as an aggregate which can be used for construction materials and shielding for radiation protection and micrometeorite impact. Binders for regolith concrete may also be made from geopolymers that may be in the regolith. The regolith can be melted and drawn out into glass fibers and used as reinforcements in a metal, polymer, or concrete matrix. In addition, there is tremendous scientific and geological knowledge that can only be obtained by studying samples of the regolith. However, none of these valuable activities can proceed without first acquiring the regolith granular material with some type of excavation device and method. Excavation is in the critical path of many workflows that will make up the capabilities required to establish a human and robotic presence in our solar system. While scientific in situ sampling of regolith in small quantities has been achieved since the dawn of the space age in the 1960s, large scale excavation for mining and construction on extra-terrestrial bodies has only been contemplated, for many decades, but serious development and prototyping of excavation technologies for use in reduced gravity space environments was only started in the late 1990s. This paper will review and document the evolution of extra-terrestrial excavation concepts and prototypes based on the available literature and the personal experience of the author who has been working on regolith excavation technology development since 1998.

The interlock drive system generates traction by penetrating narrow articulated spikes into the ground and by using the strength of the deeper soil layers to resist horizontal draft forces. The system promises good tractive performance in low gravity environments where tires generate little traction due to low vehicle weight. Possible applications include heavy-duty vehicles for civil engineering tasks like earthmoving or mining excavation. Safe vehicle operation in complex terrain geometry requires lateral vehicle stability to prevent vehicle rollover. Good lateral stability is a particular requirement for excavation and piling operations where the margins of safety define the terrain geometry that can be worked in, and it is a major constraint in operational planning. An earthmoving vehicle that can operate at a high roll angle reduces the need to maintain ramps in pits and on piles and can shorten and simplify the paths for individual maneuvers. Here we report on several field trials on the lateral stability of an earthmoving vehicle that uses the interlock drive systems. We find that the vehicle can work well at roll angles of up to 20°, but that it needs further improvement if work at roll angles of 30° or more is required.

A proposal is made to liberate water from an extensive reservoir of water bound to hydrated sulfate minerals in a geological structure under the Meridiani Planum called the Burns Formation. This formation of sediments spans the equator, is over 500 km wide, has an area larger than Lake Superior, and has depths typically between 200 m and 1,000 m. About 3 kJ of enthalpy must be transferred into the sediments for each 1 gram of water vapor liberated by dehydrating the sulfates. Relatively large energy requirements are needed to liberate water by the tonne and the kilotonne. A crucial part of the proposal is to link water liberation to power tower concentrated photovoltaic electricity generation and carbonylation steel-making, both of which produce a lot of process heat. This process heat is at suitable temperatures for dehydrating the main sulfate minerals in the Burns Formation. Carbonylation steel-making benefits from an easy-to-use source of hematite that lies in a thin layer on top of soils overlying the Burns Formation. Carbonylation steel-making produces steel powder. Powder sintering to sheet steel plus robotic cutting, welding, and bending then provide a manufacturing capability. Simple electricity generation plants and water liberation plants are described that can be manufactured locally. This makes possible a large power generation capacity on the Meridiani Planum, including a large process heat-generating capacity and a deployment of water liberation equipment that scales with the available process heat capacity.

Honeybee Robotics has designed, built, and tested a technology readiness level (TRL) 4/5 system known as RedWater, intended to drill into the surface of Mars and melt/extract water from locations identified by the Shallow Radar (SHARAD). RedWater combines proven terrestrial technologies to extract water from the subsurface Martian ice. Rodriguez Wells, or Rodwells, are a type of water well employed in Antarctica to maintain large pools of liquid water within an ice sheet and pumping water to the surface while heating and recirculating a portion to facilitate continuous well growth. RedWater also repurposes coiled tube drilling technology, which uses a thin-walled metal or composite tube to drive a bottom hole assembly into a borehole; the coiled tube itself is wound onto a drum and deployed by an injector system which transmits the required drilling forces through the tube as it is driven down. The combination of these two technologies with Honeybee’s existing rotary percussive drilling and pneumatic transport technologies make for an efficient means of producing large quantities of liquid water on Mars. Honeybee is currently working on evolving this technology to TRL 6 and will be conducting end-to-end TVAC testing in 2022.

The utilization of lunar water enables spacecraft fuel, water for colonization, and radiation shielding. To make use of the water, an industrial scale volatile extraction process is required. Current literature shows in situ extracting of volatiles from lunar regolith is difficult and doesn’t scale well. Supplying heat to subsurface ice is difficult due to the thermal conductivity properties of regolith. And subsurface water vapor has difficulty moving through dry regolith which has low permeability. These conditions are amplified when the ice weight content is low. This study will show, that extraction of volatiles from excavated icy regolith is simplified through the use of a rotary extraction drum. A rotational system extracts 99% of volatiles, regardless of ice weight content in as little as three hours. This study also quantifies the energy consumed during extraction at varying water concentrations of cryogenic icy regolith simulants. An industrial scaled version is discussed to show how a single rotary extraction drum is able to process 1 mT of icy regolith every three hours.

There is sufficient evidence provided through remote sensing and the LCROSS impact study, that water and other hydrogen bearing molecules exist in lunar permanently shadowed regions (PSR). This information while invaluable does not provide the localized prospecting information required by space agencies and mining corporations to invest in extraction of volatiles. Data on where the volatiles are located would be needed in order to create proven volatile reserve. This study demonstrates how a simple thermal sensor detects differences in thermal diffusivity in icy regolith with varying amounts of cryogenic water ice. We will show how the apparatus simulates a PSR environment, and how utilizing the simple sensor differentiates general water ice mass percentages. We will also discuss the time and energy required to execute a single sample cycle for efficient prospecting in PSRs.

Honeybee’s RedWater system is being developed as an in situ resource utilization (ISRU) approach to mining glacial ice on Mars. Our investigation addresses the environmental and geological considerations vital for system success (e.g., site latitude, ice purity, nature of impurities, and constraints on overburden). We will present an assessment of several site locales suitable for the implementation of the RedWater system using existing orbital spacecraft data. A combination of radar sounding, imagery, and other data at landing-site scales will enable constraints to be placed on the thickness, properties, and distribution of ice resources and overburden.

NASA’s Space Technology Mission Directorate (STMD) is funding the development of a robotic excavator called the “ISRU Pilot Excavator” (IPEx) which will be a technology demonstration of excavating and transporting 10 metric tons of lunar regolith on the surface of the Moon with a 30 kg-class robotic excavator. IPEx will be the next generation of robotic excavators to use bucket drums as excavation tools. This is an evolution of the regolith advanced surface systems operations robot (RASSOR) developed at NASA’s Kennedy Space Center (KSC). Bucket drums are hollow cylinders with regularly spaced scoops around the perimeter. The drums rotate in one direction to collect regolith with the scoops. The regolith slides down an internal baffling system inside the drum which prevents the regolith from falling back out of the scoops. The captured regolith can then be transported while held in the drum and then deposited by rotating the drum in the opposite direction allowing the regolith to slide back down the baffling and out of the excavation scoops. Bucket drums were developed by Lockheed Martin in 2008 and used on multiple robotic excavator prototypes ever since. However, the forces on a bucket drum and considerations for scaling have not been measured in detail. Bucket drums are challenging to model using classical blade\bucket equations because of their unique geometry. Therefore, this experiment was performed to measure the forces on three bucket drums of the same geometry at different scales. Small: 9.4” (239 mm) dia. × 8.1” (206 mm) width, medium: 11.6” (294 mm) dia. × 10” (254 mm) width, and large: 17” (432 mm) dia. × 14.1” (358 mm) width. The test stand consisted of an actuated gantry with controlled motion in the vertical (Z) and horizontal (X) axes and a single rotation axis (R). The bucket drums were individually mounted to the rotary axis of the test stand and translated across a prepared bed of Black Point 1 (BP-1) lunar regolith simulant at a specified linear speed and cutting depth. The test stand was outfitted with a torque sensor in line with the rotation of the drum (R) and a 3 axis (X, Y, and Z) load cell. In addition to the three sizes of bucket drums the linear excavation speed and cutting depth were test variables. The results of these experiments show the relationship between the three scales of bucket drums for factors such as: excavation force, torque due to regolith rotation inside the drum, excavation energy, time to fill, etc. and will be discussed in detail in this paper. This fundamental data will be used in the design of IPEx and can inform the design of future bucket drum excavators.

Climate change is the defining issue of our time. Decarbonizing Earth's economy and removing existing carbon from the atmosphere are mandatory steps for addressing climate change, but may not occur quickly enough to avoid catastrophic global warming. Space-based solar radiation management is one technique to address global warming by deflecting a small percentage of incoming solar energy before it enters Earth's ecosphere. The concept of a planetary sunshade is a physical, thin-film structure of about one million square kilometers, placed at Sun-Earth Lagrange 1, to mitigate or even reverse global warming. If the sunshade is made from space resources, it could provide a powerful objective for developing a space resources economy built on megascale construction. The planetary sunshade could require hundreds of megatonnes of material to build; this scale of space resource utilization has only barely been considered. In August of 2021, the Planetary Sunshade Foundation, in conjunction with the Colorado School of Mines, held a workshop to begin development of a space resource utilization plan with an emphasis on the scale needed to construct the sunshade. The workshop had 25 attendees, representing civil space agencies, industry, academia, and researchers from six countries. Working groups focused on resource extraction and processing and logistics for both lunar and asteroidal resources. These groups discussed the current state of knowledge, knowledge gaps, and future work required for extraction and processing techniques and logistics architectures. The purpose of this paper is to describe the key findings and conclusions of that workshop.

Honeybee Robotics is developing a next generation drilling system called SMART (Sensing, Measurement, Analysis, and Reconnaissance Tool) for lunar in situ resource utilization (ISRU) applications. SMART is a rotary percussive drill mounted on a linear stage, similar to The Regolith and Ice Drill for Exploration of New Terrains (TRIDENT) that is flying to the Moon in 2022 and 2023. Unlike TRIDENT, which uses the auger to move drill cuttings up to the surface for analysis, the SMART auger and bit assembly is integrated with instruments that can perform analysis in situ. By instrumenting the auger, we are changing the paradigm of exploration—we are bringing an instrument to the sample as opposed to bringing the sample to an instrument. The auger will now be an instrument with sample analysis capabilities. Honeybee Robotics has designed and fabricated a prototype for SMART and is adapting an existing rotary percussive drill called RANCOR to be used to conduct tests in a relevant lunar environment.

The unclear nature of ice deposits within the lunar permanently shadowed regions poses many challenges to prospecting and utilisation of those resources. Recent recalculations of LCROSS data suggest that ice concentration is more likely depth-dependent, which may also be similar to Martian ice tables. Heterogeneous deposits have to be analysed in the frame of thermal mining architecture to inform us about the expected performance and drawbacks of the technology, which currently is the most promising method of ice extraction beyond Earth, able to produce multiple tons of water per extraction. In this paper, a reworked combined heat and mass transfer model is utilized to provide further insights into phase change dynamics, when beamed energy is applied to a heterogeneous instead of a homogeneous deposit. New strategies are shown to counter performance loss due to sublimation lag build-up and bulk thermal conductivity decrease. Strategies include continuous thermal mining and fracking-thermal mining methods. The first method is analysed with a combined heat and mass transfer model and compared to the expected outcomes in the original thermal mining method. Bulk granular ice is also introduced in the modelling to show thermal mining performance in a more likely scenario of porous ice deposit.

The Planetary Surface Technology Development Lab (PSTDL) purchased a new testing facility in the form of a dusty thermal vacuum chamber (DTVAC). This facility will be used to test the technology readiness level (TRL) of devices intended for extraplanetary use. Environments such as those found on the Moon and Mars will be simulated in the DTVAC via use of vacuum pumps, thermal shrouds, and simulated regolith. This paper details the commissioning and testing of systems put into place to facilitate TRL testing such as data acquisition systems, test fixtures, and baseline DTVAC performance tests. The PSTDL has purchased two insulated shipping containers that will allow for the creation and reclamation of icy regolith. Icy regolith test beds will be used in the DTVAC to test the TRL of water in situ resource utilization (ISRU) devices.

Molten regolith electrolysis (MRE) is a space resource utilization technology with the potential to provide a dependable source of oxygen to astronauts in upcoming Artemis missions. Honeybee Robotics and NASA Kennedy Space Center’s SwampWorks Lab have designed and constructed a technology development test bed for the MRE process. The team has used this test bed to develop subsystems related to introducing granular material, melting regolith with a variety of methods, electrolyzing the melt pool, removing byproducts, and regulating these processes to optimize the electrolysis process. Honeybee has specifically focused on a combined Joule heating and concentrated solar heating process to form the melt pool. In this paper we will discuss the background and relevance of MRE, specific aspects of the test bed’s design, test parameters and results, ongoing work, and conclusions based on the work performed. Of specific interest is the alternating use of Joule heating and solar heating as the melt pool forms, oxygen evolves, and melt pool dynamics drive a changing melt pool resistivity.

The Regolith and Ice Drill for Exploration of New Terrains (TRIDENT) is an ice mining drill under development for two exploration/ISRU missions to the Moon: Volatiles Investigating Polar Exploration Rover (VIPER), and PRIME-1 (Polar Resources Ice Mining Experiment). Both missions are targeting South Pole’s volatile rich deposits. The primary goal of TRIDENT is to deliver volatile-rich samples from up 1 m depth to the lunar surface. Once on surface, the material would be analyzed by mass spectrometer observing lunar operations (MSolo) and/or the near infrared volatile spectrometer subsystem (NIRVSS). In addition to being tool for providing samples, TRIDENT is also an instrument. TRIDENT drilling power and penetration rate is used to determine regolith strength. TRIDENT’s integrated heater and temperature sensors could measure downhole temperature and thermal conductivity. TRIDENT will also be able to provide bearing capacity of the top lunar surface as well as regolith’s in situ density to 1 m depth.

Partitioned methods allow one to build a simulation capability for coupled problems by reusing existing single-component codes. In so doing, partitioned methods can shorten code development and validation times for multiphysics and multiscale applications. In this work, we consider a scenario in which one or more of the “codes” being coupled are projection-based reduced order models (ROMs), introduced to lower the computational cost associated with a particular component. We simulate this scenario by considering a model interface problem that is discretized independently on two non-overlapping subdomains. We then formulate a partitioned scheme for this problem that allows the coupling between a ROM “code” for one of the subdomains with a finite element model (FEM) or ROM “code” for the other subdomain. The ROM “codes” are constructed by performing proper orthogonal decomposition (POD) on a snapshot ensemble to obtain a low-dimensional reduced order basis, followed by a Galerkin projection onto this basis. The ROM and/or FEM “codes” on each subdomain are then coupled using a Lagrange multiplier representing the interface flux. To partition the resulting monolithic problem, we first eliminate the flux through a dual Schur complement. Application of an explicit time integration scheme to the transformed monolithic problem decouples the subdomain equations, allowing their independent solution for the next time step. We show numerical results that demonstrate the proposed method’s efficacy in achieving both ROM-FEM and ROM-ROM coupling.

A material model which incorporates several key capabilities which have been identified as lacking in currently available composite impact models has been developed. The material model utilizes experimentally based tabulated input to define the evolution of plasticity and damage as opposed to specifying discrete input parameters (such as modulus and strength). It has been implemented into the commercially available transient dynamic finite element code LS-DYNA as MAT_213. The model can simulate the nonlinear deformation, damage, and failure that take place in a composite under dynamic loading conditions. As MAT_213 is now being used by a general user community that did not participate in the model development process, a number of issues have been identified that caused uncertainty in assembling a MAT_213 input deck and conducting a MAT_213 analysis. The overall goal of this effort is to develop a quantified set of lessons learned and best practices which will permit a new user to conduct useful MAT_213 simulations without needing to have detailed expert knowledge of the material model and its theoretical underpinnings.

This paper investigates a weakly nonlinear metamaterial with electromechanical local resonators coupled to a resistance-inductance shunt circuit. An analytical solution is developed for the system using the perturbation method of multiple scales, and validated through direct numerical integration. Linear and nonlinear band structures are used for parametric analysis of the system, focusing on the effect of system parameters on band gap formation and vibration attenuation. In addition, the effects of nonlinearity and the interaction with shunt parameters are examined. Results describe multiple methods of tuning band gaps and pass bands of the system through various parameters, demonstrating the flexibility and potential of the examined metamaterial.

As a part of the FAA’s Aircraft Catastrophic Failure Prevention Program, advanced Aluminum 2024 and Titanium 6Al-4 V material models utilizing *MAT_224 in LS-DYNA have been developed to improve the numerical modeling of turbine engine blade-out containment tests required for certification of aircraft engines. In this effort, NASA conducted four ballistic impact tests on large flat Aluminum 2024 panels with a blade-shaped Titanium 6Al-4 V projectile to provide experimental data to evaluate the numerical material model. These tests were designed to represent a realistic turbine engine fan-blade release event. In this research, ballistic impact tests were simulated using advanced Aluminum 2024 and Titanium 6Al-4 V material models to validate the material models under simulated turbine engine blade release event conditions. The research also identifies possible challenges for such a ballistic impact simulation with a blade-shaped projectile that slides, bends (plastically deforms), may fracture, and rotates as it moves in three dimensions.

The influence of heat input on the tensile-test fracture location of bead-on-plate welds duplex stainless using an automatic MIG welding machine was investigated. An experiment-based thermal analysis has been performed to obtain the thermal histories, which can be applied to determine the peak temperature for different welding conditions. The temperature distribution during the welding process significantly affects the mechanical and metallurgical properties of a weldment. The changes in microstructure in a weldment are very dependent on the temperature distribution. Based on these facts, this research aims to develop an analytical model for predicting the tensile-test fracture location of the welds varying heat input during the welding process. For this study, a 3×3 matrix with a low, medium, and high level for each of the welding parameters will be applied, giving a total of 27 weld bead plates. Temperature distribution curves have been drawn. Two tensile specimens were manufactured from each welded plate, resulting in 54 tensile specimens for testing. The results show that the fracture location measurements increase until a maximum of HI of 1.267 kJ/mm then decrease.

In this study, the capability of finite element model (FEM) analysis to assess aircraft structural response and occupant injury risk during aircraft water ditching conditions was evaluated. A FEM of the Fokker F28 aircraft, previously validated against full-scale crash test data, was simulated in a realistic water impact environment utilizing recorded conditions from the ditching of US Airways Flight 1549 into the Hudson River. The FEM of the F28 aircraft, was developed from a NASTRAN loads model provided by the vehicle manufacturer, calibrated using component fuselage drop-tests, and validated through test-analysis comparisons from a full-scale crash test of the F28 onto soil. Simulation results are presented in several categories: vehicle kinematics, structural accelerations, damage, occupant responses, and injury risk predictions. Results were consistent with the general outcomes of Flight 1549, indicating that the developed vehicle FEM, validated against land impact test data, may provide an effective tool for evaluating water ditching events.

Analysis of radiation effects on electrical circuits requires computationally efficient compact radiation models. Currently, development of such models is dominated by analytic techniques that rely on empirical assumptions and physical approximations to render the governing equations solvable in closed form. In this paper we demonstrate an alternative numerical approach for the development of a compact delayed photocurrent model for a pn-junction device. Our approach combines a system identification step with a projection-based model order reduction step to obtain a small discrete time dynamical system describing the dynamics of the excess carriers in the device. Application of the model amounts to a few small matrix-vector multiplications having minimal computational cost. We demonstrate the model using a radiation pulse test for a synthetic pn-junction device.

Saline water causes a number of serious problems for both shoreline constructions and freshwater aquifers; what's more, coastal aquifers face major problems such as seawater intrusion into the interface and a decreasing in the amount of water resources during drought when water allocations from surface resources are lower less than normal. It is proposed that by injecting TSC into the interface area at a specified depth it would be possible to isolate against saline water intrusion. In 2004, huge salt domes were identified in the Gotvand Dam reservoir which could if released affect the freshwater in the Karun River. TSC grout can be used to isolate salt formations in the form of vertical curtain. SEM imaging at a resolution of x2,000 have shown the adhesiveness of fibers in TSC. The images show that fibers and salt concrete blend producing the ancient mummification techniques. TSC can reduce the costs and time of grouting.

Connected structural systems, such as overhead power distribution systems, could fail to function normally under extreme events or environments when the typically anticipated loadings are exceeded. Consequently, in structural designs, the tradeoffs between costs and accepted risks under such extreme loading scenarios need consideration. To this end, structural optimization methods could be applied to minimize costs subject to constraints on the design feasibility. While classical structural optimization techniques are deterministic, risk-based approaches considering the probabilities of structural failure under certain contingencies have been less explored. In the present study, a structural optimization framework is developed and tested on a power distribution system subject to extreme storms. Uncertainties in the material properties, loadings, and construction are integrated for a risk-based assessment with constraints on the acceptable pole failure probability. Various combinations of extreme storm scenarios and acceptable failure probabilities are investigated to explore the risk-cost tradeoff and optimal design criteria. By employing the use of high-class, shorter poles, the optimal configurations are found to reduce the cost for a similar reliability level by about 50%, while, for a similar cost, the system could be designed to a much higher reliability level. Such a framework could be adopted for a variety of structure types and systems under various extreme environments, including future habitats on the Moon or Mars.

Civil and military interest in space-based operations has increased dramatically in recent years due to advancements in space travel and discoveries, like water on Mars. Discussions have centered on the establishment of permanent infrastructure in extraterrestrial environments. Selecting appropriate construction materials and techniques requires that extraterrestrial civil engineers and understand candidate materials to determine their dynamic life-cycle costs. Robust and detailed systematic reviews have previously been completed on the research in this field however, these analyses do not provide intercomparisons of proposed materials or are not within the last decade. The rapid rate of new research in this area demands systematic reviews be performed at short intervals. To address these issues, this work produces a systematized review of literature that covers four construction materials: aluminum, biopolymer soil composite (BSC), sulfur concrete, and regolith. Here, several factors unique to space-based operations, including radiation resistance, high-impact strike resistance, thermal insulation/vulnerability, recyclability, material life cycle cost, and constructability are evaluated through a literature review to compare the feasibility of each material. The results of this analysis intend to inform both researchers and practitioners as they consider the vast distances materials must be transported, and the harsh and uncertain environmental conditions to which materials will be exposed.

Bolted steel structures may be subjected to many adverse effects, such as corrosion, vibration, shock, and seismic excitation, which reduce the strength of the bolted connection and thereby weaken the whole structure. Therefore, monitoring the health of bolted connections is very important in ensuring the safety of structures. In this paper, a two-story bolted steel frame with braces was used in the detection of damage to a bolted connection. The piezoelectric-based active sensing method was utilized to evaluate the damage condition of the connection. Various degrees of corrosion and bolt loosening in various positions were simulated during the test to verify the effectiveness of the proposed method. Both the impact waves and the sinusoidal excitation waves produced by impact test and a piezoceramic actuator respectively, provided active sensing stress waves. The continuous wavelet transform was adopted to process the received piezoelectric signal and to evaluate the damage index. The energy-based damage index was used to predict the severity of damage to a bolted joint, allowing slightly corroded bolts to be accurately detected. This work reveals that the health status of the bolted connection is influenced by the severity of corrosion of the bolt, and the presented diagnostic method is effective in monitoring the severity of corrosion and the degree of bolt loosening of a bolted connection.

A novel type of buckling restrained brace (BRB) utilized the super-elasticity of shape memory alloys (SMAs) is developed, and a new assembly of restraint parts is proposed to solve the problem of poor restorability and non-replacement of traditional BRBs. The novel BRB components are simplified and modeled by using the ABAQUS platform to study the seismic and resilient properties. The axial carrying capacity and hysteresis energy consumption capacity of both the novel BRB components and the traditional ones are analyzed and compared, respectively. The numerical results show that the new assembly of restraint parts of the novel BRB component can improve the hysteresis energy-consuming capacity about 10% under the same condition as the core energy-consuming components. The SMA-based novel BRB component as the core energy-consuming one behaves typically as the “flag-shaped” hysteresis curves, and the SMA-based and replaceable BRB components have good seismic and resilient performances. The influence of gap measurement between the restraint component and the energy-consuming component on the performance of BRB is also analyzed.

In this paper, the seismic response of lava tubes was estimated. Several dimensionless numerical analyses were carried out for various dimensionless geometries. The effects of key influencing factors such as the depth of the lava tubes, the gravitational effect of the Moon, and the frequency content of the incident motion on the dynamic response of lava tubes were studied. The findings can be useful in geotechnical moonquake engineering and lunar seismology and provide some practical insights into the design of future moonquake-resilient human habitats on the Moon.

Development of the lunar surface will likely be a pivotal step in the emerging space economy. In recent years it has been confirmed that water is present in the polar craters of the Moon. The Moon is also rich in iron, titanium, and silicon; which may be mined with the appropriate lunar facilities. Motivation to erect a lunar base aligns with the NASA Artemis objectives for a human return to the Moon. In order to achieve Artemis objectives, bases must be erected in a manner that allows for flexibility and mobility. In this way, semi-permanent structures are an ideal mode for facilities to exist on the lunar surface. The optimal method to achieve these structures would be to utilize existing sandbag technologies to innovate lunar-appropriate bases. In the early stages of prospecting and open pit mining, there will likely need to be mobile pilot bases setup that need to perform in-depth evaluation and attempt pilot scale mining at different sites before permanent structures can be installed. We propose simple, multifunctional building blocks such as “smart sandbags” for constructing rapid, low-cost semi-permanent structures. Smart sandbags are filled with lunar-regolith and embedded with structure and impact sensors, and adopt a designed 3D customizable shape. The sandbags will be made of carbon fiber fabrics and integrated with silicone to combat the abrasiveness of lunar sand. Options for rigidization of the sandbags will also be explored with methods such as UV-cured resin or hydrogel. Innovatively designed features of our sandbag structures include the ability to be quickly assembled and disassembled, utilization of in situ resources, and effectiveness under a variable number of ground conditions. The semi-permanent structures are expected to provide shielding from collisions, radiation, maximize surface traction, and provide human habitat. Our studies show that the feasibility of the sandbag structure for use under different lunar surface conditions. Further in-depth investigations will need to be performed to quantify the potential improvement offered by sandbag structures over conventional brick laying and additive manufacturing.

The pointer meter is an essential component of industrial facilities such as substations, oil fields, buildings, and construction. The readings represented by its pointer record various environmental parameters and equipment operating parameters of industrial facilities. The traditional manual meter reading method is time-consuming and requires professionals to operate it, which has a high demand on labor costs. Therefore, we propose a computer vision-based method for the reading of pointer meter. Through image local feature matching, the algorithm realizes the autonomous correction of image in-plane rotation, and effectively reduces the recognition error caused by image in-plane rotation. Moreover, this method can realize the function of automatic reading of the pointer meter without additional training. The results show that the readings obtained by the proposed method are close to those obtained by manual meter reading and meet the requirements of industrial use.

The building structure and equipment of substations are exposed and are subject to environmental factors, which can produce deformation. Once the equipment of the substation fails due to excessive displacement, it will seriously endanger the substation safety and affect the power supply. The traditional manual inspection method of a substation is challenging to observe the slight deformation of the substation. Thus, a displacement recognition method of substation is proposed based on vision. The state-of-the-art object recognition technology was applied to build a calibration object recognition model. In recognition of structural displacement, the calibrator is fixed on the substation structure. The camera recognizes the pixel change of the calibrator, and then the structural displacement is calculated. Finally, the proposed method is validated. Results show that the application of the mobile terminal-based method proposed in this paper is considerably close to the actual displacement, which meets the requirements for industrial use.

Before and since Vitruvius Pollio’s recognition as the first “architect,” the basic principles of architectural design and construction have been debated and reworded with each influential individual defining specific principles of design pertaining to their own era of design. Despite all the debate, at their core, these principles outline the various considerations required to create a logical, inspired, and beautiful design for a space, a building, or even a city. The advancement of technology has challenged some of these primary principles and added additional complexity to their traditionally understood definitions. Similarly, construction practices have advanced due to the development of technologies such as computer assisted drafting and the more recent advent in the last two to three decades of building information modeling. No longer are people carving large blocks of stone by hand in order to form a wall. However, the progression of the advancement of construction practices has not evolved at the same rate as technological advancement. This disconnect creates exponential challenges when considering construction methodologies, architectural design, and materiality features in extraterrestrial construction. Understanding the advantages and limitations of the known techniques and principles provides a launch point for future development specifically designed for extraterrestrial construction requirements. Beyond the traditional design principles, sustainability and materiality must move to the forefront for the project's consideration due to the expense and challenge of moving materials, products, and construction teams to a lunar or Martian environment. This means traditional principles and practices for architecture and construction need to be developed and adapted to meet the unique requirements of the challenges associated with an extraterrestrial project site. Use of native, local materials takes on a new meaning when considering the types of resources available in a Martian or lunar environment. Site selection and orientation is also limited by topography, soil (regolith) conditions, and the availability of adjacent spaces for landing pads or longer distance “road” networks. Finally, simplicity in constructability becomes of paramount importance when considering the autonomous and robotic techniques likely to be required when preparing for extraterrestrial construction.

Humankind has not set foot on the Moon in more than half a century. Since then, our best chance to get back to the Moon and stay, is now, with the Artemis program, led by National Aeronautics and Space Administration (NASA). To achieve a lunar presence for longer than 3 days, the astronauts will need a safe lunar habitat that will protect them from the harsh environment on the lunar surface. When designing for a structure that is quite literally out of this world, there are many different factors to be considered, which are not present on Earth. Humanity went through thousands of years of construction to develop their understanding of structural shape effectiveness, construction material, understanding of the stresses and forces that are present in the Earth environment, and summarized them into various building codes. However, most of that knowledge is not applicable for the lunar environment due to different factors and lack of atmosphere. Various conceptual designs were presented and published around the world, but a more comprehensive study needs to be conducted to account for all the technical requirements and extreme factors affecting the decision of the lunar habitat. This paper briefly summarizes the most important data on the technical requirements and environmental factors to be considered for a successful design and continues with development of a preliminary in-depth and systematic framework, through the Pugh Matrix, to determine an optimal design for a lunar structure. 23 different evaluation criteria were used. Even though numerous different lunar habitat concepts were published throughout last 50 years, they were summarized in eight different concepts. The full decision matrix is presented, with the 3D printed structures as baseline concepts, and Modular Block Structures as the most viable option.

Sedimentary rock and clay mineral deposits are known to exist on Mars. Substantial amounts of water ice in the form of polar caps, glacial deposits, and subsurface ice are also a recognized natural resource. Dry stacked stone construction, stones placed without the use of mortar, using sedimentary rocks is the oldest form of durable building used by humans. Mud bricks, composed of clay and water, used by early civilizations in the deserts of Earth, created monumental and iconic structures, some of which have endured for more than a thousand years. Concrete a mixture of sand, gravel, and a binding agent can also be produced from Martian materials. Masonry construction, the use of stones, bricks, and concrete will create the first generations of truly Martian buildings, which will endure for centuries. Construction techniques associated with heavy masonry construction on Mars are described.

The development and properties of MgO-clay-based engineered M-S-H cement mortar and concrete with Martian regolith simulant filler is presented in this study. Engineering properties for the M-S-H cement include compressive strength, tensile strength, Poisson’s ratio, elastic modulus, bond strength, and incorporate durability indicators such as porosity, permeability, and resistivity. Additionally, the structural response of reinforced engineered M-S-H concrete columns under lateral loads is compared with the performance of columns cast with conventional portland cement (PC) concrete. These findings demonstrate that the properties of the MgO-clay cement concrete can be effectively manipulated through variations, either in the cement formulations or in the mix proportions, to suit the functional requirements of proposed Martian applications. Engineering properties and the structural performance of the reinforced concrete sections made with the engineered M-S-H concrete were similar to those demonstrated by the columns made with PC concrete, thereby, making it a suitable material for both Martian and Earth-based construction.

We consider whether an entire spacecraft can be constructed from lunar resources by consideration of its materials availability. We first consider what functional materials would be required to construct all the major spacecraft subsystems. We then examined each lunar mineral to determine what metals, ceramics, and glasses can be extracted. We suggest that lunar resources—with certain provisos—can indeed supply all the functional materials required to construct a spacecraft. We suggest that this could constitute a first generation ISRU capability and that a subsequent generation to extract KREEP materials would offer enhanced performance but no significantly greater capacities.

For sustainability, any lunar assets must be maintainable from local resources including electronics. We review the nature of electronics fabrication using solid-state manufacturing for transistors and determine that it is not feasible on the Moon. Material availability on the Moon suggests that an alternative technology—the vacuum tube—is feasible. The large footprint overhead of the traditional CPU-based architecture may be avoided by implementing recurrent neural network architectures. This model of general purpose computing closely resembles the original Turing machine in which a magnetic core memory acts as input to a 3D printer which outputs neural net circuitry.

We explore the notion of constructing SPS from lunar resources. We review several aspects of SPS design and determine that two core components that will be essential to SPS are the magnetron and the rotary joint. The magnetron is a vacuum tube device that may be constructed from lunar resources—a CaO-coated tungsten cathode, Ni control grid and anode, fused silica glass tube with elements of the electric motor. The rotary joint is a DC electric motor comprising hard and soft magnetic materials and wire coils which may be manufactured from AlNiCo alloy, ferrites, and kovar wiring respectively which can be sourced from lunar material. The DC electric motor has been successfully 3D printed while the vacuum tube magnetron has yet to be.

Lunar launch and landing pads are necessary to mitigate risks to lander/ascent vehicles and surrounding surface assets from rocket plume ejected regolith. Significant risks exist for the larger landers proposed for the Artemis Program due to higher thrust levels leading to increased ejecta and cratering, presence of co-located assets in the ejecta path, and potential strict surface levelness requirements for tall vehicles. Regolith-thermoset polymer composite materials were developed and evaluated for off-Earth launch and landing pad applications. Performance under methane-oxygen rocket engine firing conditions was assessed for simulated Starship lunar launch/landing environments. Though significant erosion was experienced during some testing conditions, all test articles successfully mitigated regolith ejecta from plume effects. The mass of polymer required to be landed on the Moon constitutes a primary risk for the application of regolith-thermoset polymer composites as a lunar launch/landing pad. A Starship with planned 100 t payload capacity to the lunar surface could provide enough polymer mass for all but the largest pad sizes. A concept for preparing and emplacing the materials was developed and tested in laboratory conditions. The testing evaluated the feasibility of using screw extruder technology to mix, convey and deposit materials. Screw extruders were capable of processing and extruding the composite with a maximum of 90% mass fraction of regolith achieved. The feasibility of the regolith-thermoset polymer composite based construction approach was proven in three critical areas: performance under engine firing simulating launch/landing conditions, fitting within the planned lunar payload capacity, and demonstration of a mixing and depositing concept. The materials must be proven to be compatible with lunar environments. It is recommended that development continue to TRL 6 for a small-scale lunar demonstration.

Microwave sintering is regarded as one of the most appropriate technologies that enable in situ resource utilization (ISRU) surface construction for future lunar base development. During the process of microwave sintering, electromagnetic radiant energy is absorbed by the lunar soil grains whereby temperature increment and bonding of grains take place. However, due to the anisotropic electromagnetic field and thermal runaway phenomenon, a temperature gradient could occur in the sintered regolith grains. This can induce local flaws (such as cracks) and enclosed pores inside the sintered body. To examine and improve the functionality of microwave sintering, this study used microwave sintering of a lunar soil simulant and conducted experimental materials characterization of sintered specimens and finite element model simulation of the sintering process. Physical and mechanical properties of the bulk sintered samples were evaluated to assess the feasibility of microwave sintering for ISRU surface construction of future lunar base. In order to account for several coupled phenomena in the process of microwave sintering, COMSOL multiphysics finite element code was used to simulate dielectric heating in a microwave cavity by integrating electromagnetism and heat transfer. The temperature gradient within the sintered body was evaluated in different sintering stages. Parametric analysis in the finite element simulation was also conducted to examine a cavity design that can provide a less temperature gradient and enlarged sintering products. Results and insights from this study are expected to improve the functionality of the hybrid microwave sintering and its potential implementation into the ISRU-based lunar construction.

Through the Artemis program, NASA will extensively explore the Moon in preparation for the first human mission to Mars. NASA is planning to return to the Moon in the next few years, to establish a strategic presence at the Lunar south pole. To promote a long-term sustained presence, planetary surface construction technologies are needed to build a variety of supporting structures such as habitats, radiation shields, protective hangars, and launching and landing pads. Construction 3D printing (C3DP) is an autonomous construction technology that employs the principles of additive manufacturing on a structure scale. While C3DP has been mainly used for terrestrial construction, it is also considered a viable robotic construction technology for planetary infrastructure buildup. In this paper, the challenges and possibilities of extrusion-based planetary C3DP will be discussed in detail. Moreover, the results of an ongoing experimental study, as well as future research plans will be presented.

As space agencies again turn their sights to lunar exploration, they will find a dearth of modern technologies at TRL 7–9 for the lunar environment. As a remedy, NASA is enabling new commercial testing services in tandem with commercial partners to provide a path for achieving TRL 8 or 9 through technology demonstrations on the lunar surface, including two from Aegis Aerospace, Inc. Transport to and operation on the Moon require survival of thermal extremes, extended radiation exposure, hard vacuum, pervasive dust, and other lunar peculiarities. In addition to environmental considerations, practical size, weight, and power (SWaP) considerations require systems to balance mass and structure, design electronics and software for power and bandwidth restrictions, and devise intelligent operations and ground systems. In combination with traditional verification and validation, several comprehensive tests are appropriate for lunar operations, including dusty TVAC, orbital demonstrations, and integrated mission lifetime testing at the payload and system levels. However, it is impossible to fully replicate the lunar environment, resulting in residual risk that cannot be fully mitigated with testing in simulated environments. While the lunar environment harbors many unknowns, this paper provides information for successfully designing, developing, and testing the technologies that will be integral to establishing a constant presence on the Moon.

This paper presents a series of laboratory testing conducted to investigate the feasibility of sulfur-based Martian concrete for extraterrestrial 3D printing applications. Several mixes with varying proportions were made and tested for desirable 3D printing properties. The mixes consisted of majority sulfur and Martian regolith simulant, with some additives such as magnesium oxide and glycol plastic explored to achieve ideal properties for 3D printing. When testing the fresh mixes, three criteria were used to quantify the properties of a 3D printing mixture: pumpability, printability, and open time. Aside from the 3D printing properties of the fresh mixes, small beams and cylinders were cast and tested to investigate their final flexural and compressive strength. Overall, the test results revealed that the mixes containing both fine and superfine Martian regolith performed better in the pumpability and the strength tests than those containing only one size.

Previous lunar missions and campaigns have been restricted to using robotic landers and lunar orbiting satellites as well as sortie type of operations using astronaut crews (NASA Apollo program). Now, the next phase of lunar exploration has begun under NASA’s Artemis program and there has been an international response where other nations such as China, Russia, India, Canada, Japan, and the European Union of nations, have all expressed interest in either collaborating or competing with NASA on the Moon. This next phase has an overarching goal of achieving a permanent human presence on the Moon via sustainable methods. A lunar base with human occupancy will require infrastructure to provide shelter, utilities, landing/launch pads, roads, communications, power, and all the other necessities to sustain human life and protect equipment. Since human biology is not well suited for surviving in the lunar environment, there will be many forms of automated equipment, autonomy, and robotic helpers that will minimize the amount of extra-vehicular activity (EVA) required by the crew. This will mean that the radiation dosage received by the crew will stay within acceptable and safe career doses. Radiation shielding via the use of regolith can also mitigate radiation dangers. The required infrastructure must be constructed, but the mass and logistics of bringing all the construction materials from Earth are prohibitive, which makes the necessary construction difficult to achieve. In situ resource utilization (ISRU) aims to solve this challenge by sourcing construction materials locally or “in situ.” This means that their transportation can be completely eliminated, resulting in large cost savings by avoiding the launch out of Earth’s deep gravity well and subsequent trans lunar injection, lunar orbit capture, and landing. This paper will give a historical review and current status of lunar construction planning and a high level introduction to the required infrastructure and construction equipment that will be required to robotically build a lunar base using in situ resources. It will also organize these tasks into logical groupings so that technology development and implementation can be pursued within a framework that can be referenced by all involved.

Disruptive robotic construction technologies such as additive deposition of cementitious materials like concrete (or “3D concrete printing”) require the synchronous operation of multiple pieces of equipment in the production setup. In such an environment, it is crucial to simulate the robotic motions (for toolpath clashes) and the cementitious material behavior (for toolpath failures) to ensure fail-proof constructability of the envisioned building geometry. However, toolpath clash detection requires 4D simulations of the production setup, which are computationally graphics intensive, whereas toolpath failure detection requires actual 3D printing of test parts from the geometry to identify areas prone to failure while 3D printing, which is physically tedious. Both these processes, being computationally and physically intensive, have largely curtailed designers from simulating and exploring large sets of design options with varying geometries and toolpath configurations. To overcome this and allow designers to explore large sets of design possibilities, this paper proposes two novel computational metamodels capable of performing robotic toolpath clash detection and failure detection with significantly reduced times than the earlier approaches. The developed metamodels were used to rapidly simulate large sets of building design options for robotic constructability in the NASA 3D-Printed Mars Habitat Challenge.

This paper presents and discusses strategies for integrating XR technologies into iterative design processes for modelling and testing space structures, specifically habitats and other facilities for crew operations. The proposed methodology was developed during a six-month research and design study of lunar surface architectures sponsored by The Boeing Company and conducted by the faculty and students of the University of Houston’s Sasakawa International Center for Space Architecture. The study aimed to define a design process that includes possible surface operations scenarios (ConOps), development of an evaluation methodology, and surface ConOps analysis for the conceptual design of a lunar terrain vehicle (LTV) and a small lunar habitat (SLH). Design decision validation methodology involved development of a 3D computer model of surface systems that included a small lunar habitat and lunar transfer vehicle, in addition, low fidelity physical operation elements such as a STB of a selected size were developed for integrating it within the created VR environment for immersive testing and evaluation. The proposed in the study framework suggests a number of available technologies that are part of the industry standard for VR applications. The objective of the phased implementation strategy is to integrate a new evaluation process in the testing loop without disrupting currently employed design validation standards, offer a new capability that will provide an in-depth design analysis improving the overall design process, and interfacing it with current evaluation standards. The paper presents the results of the study and defines the next steps of advancing XR technologies applications for testing and evaluation of design solutions for space applications. Such steps will include defining the limitations of XR applications for testing and validating design options and associated interfaces; the most efficient way of integrating ConOps and mission scenarios in the simulated environment; and technology requirements for performing immersive simulations and design evaluations.

Human exploration of the space of the Heliosphere (and beyond) is strongly linked to the ability to use local resources. Despite the trend that sees a progressive growth in the useful payload of the new generation carriers, establishing a constant human presence and growth in the volumes of buildings on the Lunar and Martian surface is possible only through mastery in the use of materials offered by the surrounding environment. Building on or below the surface requires a deep knowledge not only of the properties of materials and construction techniques but also of the form factor of pressurized and non-pressurized constructions. The environmental conditions and properties of the regolith between the Moon and Mars, although very different, characterize the need to automate the construction processes right from the exploration phase. Studying the construction of the structures built with in situ resources utilization (ISRU) therefore also means developing a family of vehicles and robots capable of supporting the preparation of the site, the collection and processing of materials up to construction and maintenance. Since the diffusion of additive manufacturing for large-scale applications, Space Agencies like NASA and ESA have explored different strategies to address the topic, and many Earth-based technological demonstrators have been tested, with support from the private construction sector. Academic and private research entities are currently developing similar projects, using innovative techniques and near-future technologies. This paper aims to review and analyze the state of the art of space structures built with ISRU to provide an overview of techniques and technologies for the efficient use of resources In Situ, to build a methodology of approach to the design of structures suitable for welcoming human crews on the Lunar and Martian surface.

The next major milestone in space development will be to establish a semi-permanent or permanent human presence on the Moon. The Moon will become a springboard for future efforts to advance a Cislunar space economy and advance the colonization of Mars. We expect a lunar base camp rated for humans that is capable of in situ resource utilization (ISRU) will contain several facilities, such as stations for power, mining, robot operations, asset tracking, communications, material processing, geological survey lab, service, and repair station and launch/landing pads. Various parameters will be involved in the design of each facility. With so many parameters present, arriving at an optimal solution for the design of the lunar base requires the following: (1) Identifying the critical parameters involved; (2) Formulating the empirical relationships between the identified parameters; (3) Performing optimization utilizing the empirical relationships found. An early lunar base is expected to be modular, with lessons learned from the construction of the International Space Station (ISS). Site preparation tasks had initially been envisioned to be done using astronauts. However, the lunar surface is harsh, and performing dull, dirty, and dangerous tasks such as site preparation puts astronauts at risk. A compelling alternative is using robots to perform site preparation and base construction ready for human astronauts to live. In this paper, we identify the different parameters involved in constructing a modular lunar base with a focus on ISRU and aim to arrive at the empirical relationships between them. We perform a case study on a modular base with each module constructed with sandbags. Sandbags offer the lowest cost of entry towards surface construction. Sandbags are relatively easy to assemble into shelters and support structures and can be adapted to various lunar surface conditions. Sandbags structures do not require water or heat for construction. Obtaining enough water to produce the paste needed for additive building structures on the Moon is a significant challenge. In contrast, solar sintering requires high energy and relatively complex facilities to generate significant amounts of solar energy to be used in sintering and additive manufacturing. We perform a detailed analysis of sandbag structures for constructing a lunar base and critically analyze the shortcomings and what needs to be done to overcome them. First, we list out the critical parameters for each module (independent variables) and identify the interfacing requirements between modules to arrive at the dependent and derived variables. Then we use these variables to arrive at the relations to the size of the different modules and, consequently, the entire base itself. These relations may be used as a tool to arrive at configurations for lunar bases based on different objectives and requirements.

Long-term, sustainable planetary exploration will require the ability to “live off the land,” relying on in situ resource utilization (ISRU) and in situ construction as core capabilities. Reduction of both risk and launch mass for lunar construction will require evaluating and comparing regolith materials for use as feedstocks suitable for in situ beneficiation and fabrication of building components. These material assessment capabilities will inform lunar infrastructure design decisions, with co-benefits for terrestrial construction using in situ materials. Current planetary construction technology development relies on lunar mapping and orbital data, Apollo-era sample analyses, current simulant inventories, and tests conducted using analog site soils. Requirements for lunar infrastructure design decisions and construction systems will be determined based on specific environmental conditions, mission architecture, and the materials available within traverse range of lunar feedstock processing depots. Critical for success is the capability to identify, evaluate, and make effective use of a wide range of materials as they are found in situ on the lunar surface. This paper discusses the development of a digital repository for data on soil and regolith properties, beginning with their structural performance in both cementitious and non-cementitious building material formulations. The database for in situ resource testing (DIRT) compiles a catalog of raw materials, additives, and formulations, with notations pertaining to material sources and preparation techniques entered via a web-based user interface. Design of consistent data schemas for site-sourced materials evaluation will facilitate linkage with relevant terrestrial and planetary materials databases, while enabling guided data input via templates for participation by broader groups of collaborators. Results of these analyses are compiled in a centralized repository to generate insights applicable for regolith resources and landing sites yet to be precisely defined. Collection of thorough records of material characteristics, applications, and performance will support innovative construction solutions not only for space infrastructure but for sustainable, resilient design in the terrestrial built environment.

This paper presents concepts and designs for a system architecture meant to serve as an initial habitat for a human crew on the lunar surface. The system architecture’s objective is to support a crew of four on a fourteen day mission to transfer cargo from a lander to a small lunar habitat using a lunar terrain vehicle (LTV). Trade studies are conducted to evaluate the possible capabilities of each element. Design drivers for both the habitat and the LTV are identified and analyzed. During LTV design development, automation became the major design variable to drive cargo transfer scenario development. Three degrees of automation are made distinct and evaluated. Mission and system design implications for each degree of automation are evaluated. Increasing the automated capabilities of mission elements may lead to greater efficiency and safety for the crew. However, significant increases to cost and mass often accompanies any additional complexity and capabilities. The evaluation and analysis of LTV’s optimal capabilities influenced the set of requirements for designing a small lunar habitat that had to be designed for use in late 2020 and to be located at lunar south pole. The habitat design aimed to be lander agnostic with an approximate twelve-meter squared volume optimized for the crew of four during a two-week mission. The design of both elements, the rover and habitat, considered them as a system that evolutionary meant to become a part of an overall lunar surface systems infrastructure. This study concluded that elements in systems need to be minimally designed while maintaining an acceptable level of crew safety. Mixed crew and robotic operations will be necessary to the expansion of lunar outpost. This lunar outpost requires a minimally designed prefabricated habitat to begin operations.

The advancement of the human presence in space, particularly manned missions to and habitation of the lunar surface, is a topic of ongoing discussion and design. In order to seriously consider human habitation of the lunar surface, an in-depth analysis of the performance of a model habitat under the extreme environmental pressures encountered on the lunar surface will be needed for any future designs. It is for this reason that a model of the air temperature and pressure changes within the habitat expected in various scenarios will need to be developed. This study has taken the initial steps toward the development of that model. A zone-based approach has been considered to predict the pressure, temperature, and air mass flow at different points within the habitat space. The model outlined herein serves as a foundation for development of a detailed lunar habitat model which accurately models expected internal conditions without intervention.

Being terrestrial for so many thousands of years, humanity is now advancing in the direction of being extraterrestrial. Attempts made until now were quite promising, like walking on the Moon, living in stations for very long durations miles away from Earth, sending probes to unimaginable distances in space and bringing them back to Earth, etc. In the coming decades, it is easily predictable that man will spend time on Moon in lunar shelters for periods which cannot be qualified as “short visits.” This will be followed by going to Mars and other space bodies. Such achievements will be realized thanks to space research conducted in space agencies all around world, especially by countries who can afford huge amounts of money in this field. In fact, space research is a multi-dimensional, multi-disciplinary field where important contributions can be made without having much financial support. Such an approach, evidently, will increase international cooperation in the field, and will help increasing technological and scientific levels of all countries who join this research subject. Designing shelters specially adopted to lunar environmental conditions and finding ways of construction techniques for building them is but a field where many researchers from many countries can attack. A related field is producing lunar soil simulants on Earth and making experiments on them for using lunar soil as the only in situ resource available in construction and for extracting other compounds and elements that will be needed for human survival on Moon. It is to be noted that up to date 9 countries have produced lunar soil simulants and this number is increasing continuously. The last contribution is from Turkey, with the lunar soil simulant labeled TBG-1 about which general information and properties are given in this study.

This paper presents the surface temperature and temperature through thickness profile of a monolithic concrete dome habitat structure in the intact and damaged condition on the Moon. Due to long duration days and nights in the lunar environment, a habitat built on the Moon is subjected to extreme temperature fluctuations. The three-dimensional thermodynamics heat balance equation was solved using the explicit finite difference method. While the direct solar radiation and lunar albedo were used as the heat sources, non-blackbody radiation and habitat albedo were taken as heat sinks. The convective boundary condition with the constant interior air temperature of 293.15 K was used for the temperature calculation. In the intact condition, the maximum temperature of around 365 K was found at the external wall surface on crown (apex) of dome during the solar noon and the minimum temperature of around 222 K was determined during the night time irrespective of the location on the dome. For the damaged condition, the difference between daytime high and nighttime low temperature at the interior wall surface of the lunar structure can be as large as 57 K.

In 2020 ICON Technology, Inc. was awarded a subcontract through Jacobs supporting NASA’s Crew Health and Performance Exploration Analog (CHAPEA) to deliver a 3D-printed habitat, known as Mars Dune Alpha, at NASA’s Johnson Space Center. ICON utilized the Vulcan construction system to complete a 1,700 square-foot structure, designed by architecture firm BIG (Bjarke Ingels Group), that will simulate a realistic Mars habitat supporting long-duration, exploration-class space missions. The layout of the structure synthesized NASA requirements for functional habitat programs and was organized in a gradient of privacy. The habitat includes four private crew quarters, dedicated workstations, a medical station, food-growing stations, with shared recreation and living spaces in between. As a functional analog habitat, Mars Dune advances the technology readiness of multiple technology gaps relevant to additive construction for pressurized surface habitats. Among these include: the integration of Earth-brought elements such as airlocks, hatches, and a medical pass-through window, as well as the integration of modular flooring and outfitting elements for the habitat interior. As of July 2021 NASA has begun recruitment for the long-duration Mars mission analog study. Applications to participate as crew are being accepted through mid-September 2021 and the one-year analog missions are anticipated to start in Fall 2022.