In-situ Resource Utilization Research Articles

A lunar soil simulant (LSS-ISAC-1) for the lunar exploration programme of the Indian Space Research Organisation

Lunar Regolith Simulants are imperative materials required for In-Situ Resource Utilization (ISRU), simulating physical and chemical properties of the lunar terrain, testing landers and mobility of rovers, and calibration of payloads and sensors. The available simulants do not represent all the lunar terrain environments and are insufficient to conduct the above experiments. The Indian Space Research Organization (ISRO) took up necessary steps to launch the Chandrayaan-2 mission after successfully completing the Chandrayaan-1 mission. The Chandrayaan-2 mission included an orbiter, a lander and a rover. ISRO's UR Rao Satellite Centre (URSC) has decided to have a dedicated Lunar Terrain Testing Facility (LTTF) at Bengaluru. URSC has planned for a bulk quantity of lunar soil simulant similar to Lunar highland composition. The task was assigned to the Centre for Geoinformatics and Planetary Studies, Department of Geology at Periyar University in southern India. The bulk quantity of Lunar soil stimulant was produced from the anorthosite rocks collected from the Sittampundi Anorthosite Complex (SAC) exposed in the southern part of India. We report the merit of the source area, geological setting, chemistry, mineral phase, soil characteristics, and grain size distribution of simulant material. The anorthosite rocks collected from SAC have a higher abundance of calcic plagioclase, and the proportion of major oxides is mostly equivalent to lunar highland anorthosite. ISRO's lunar soil simulant LSS-ISAC-1 has similarity with the Lunar highland regolith in the majority and has fidelity to represent the highland terrain. The testing facility, LTTF, was used for testing the soft landing of the lander and mobility of the rover of the Chandrayaan-2 mission.

Iron can be microbially extracted from Lunar and Martian regolith simulants and 3D printed into tough structural materials.

In-situ resource utilization (ISRU) is increasingly acknowledged as an essential requirement for the construction of sustainable extra-terrestrial colonies. Even with decreasing launch costs, the ultimate goal of establishing colonies must be the usage of resources found at the destination of interest. Typical approaches towards ISRU are often constrained by the mass and energy requirements of transporting processing machineries, such as rovers and massive reactors, and the vast amount of consumables needed. Application of self-reproducing bacteria for the extraction of resources is a promising approach to reduce these pitfalls. In this work, the bacterium Shewanella oneidensis was used to reduce three different types of Lunar and Martian regolith simulants, allowing for the magnetic extraction of iron-rich materials. The combination of bacterial treatment and magnetic extraction resulted in a 5.8-times higher quantity of iron and 43.6% higher iron concentration compared to solely magnetic extraction. The materials were 3D printed into cylinders and the mechanical properties were tested, resulting in a 400% improvement in compressive strength in the bacterially treated samples. This work demonstrates a proof of concept for the on-demand production of construction and replacement parts in space exploration.

Review on space energy

Energy resources in outer space, also known as space energy, has been recognized as a promising supplement to conventional energy supplies on Earth, as well as an irreplaceable energy provision for future space explorations. A critical review is conducted in this paper, to identify the most potential space energy resources, to conclude on the current exploitation technologies and to suggest on the challenges and future directions. Space solar power station, also known as SSPS, is presented first as a well-known utilization of space energy, and we go through the international progress, evolution of the collection systems and the thermophotovoltaic systems. The main technical gaps hampering the practical application of SSPS is concluded then to inspire future investigations. Energy on Mars is presented afterwards as a representative ISRU(In Situ Resource Utilization)-type energy resource, and we select three potential resources on Mars worth exploitation: solar energy, geothermal energy and wind energy. A model describing the global solar irradiance on Mars is concluded, typical applications of geothermal energy is analyzed, the phase equilibrium of geothermal fluids is established and the wind turbine is designed. Furthermore, the review on energy on Moon is started with the discussion on lunar geology relevant with energy resources, and an example of feature detection using Convolutional Neural Networks is illustrated as an example to demonstrate the application of deep learning techniques in space energy exploitation. Solar energy is always taken into account in space activities, and we are more focusing on the discussion of Helium-3, a promising resource for nuclear fusion. The material for nuclear fission, Uranium, has also been detected on Moon. A summary is provided in the end with concluding remarks.

Science-rich Sites for In Situ Resource Utilization Characterization and End-to-end Demonstration Missions

Abstract Within the European Space Agency’s “Commercial In Situ Resource Utilization (ISRU) Demonstration Mission Preparation Phase,” we examined two types of lunar sites in preparation for an ISRU demonstration mission. First, we considered poorly characterized potential resource sites. For these so-called characterization sites, precursor missions would investigate the material properties and address strategic knowledge gaps for their use as ISRU feedstock. Regions of interest for characterization missions include the Aristarchus plateau, Montes Harbinger/Rimae Prinz, Sulpicius Gallus, and Rima Bode. Regional pyroclastic deposits at the Aristarchus plateau and adjacent Montes Harbinger/Rimae Prinz exhibit remotely sensed low-Ti, high-Fe2+ compositions. They differ from the high-Ti pyroclastics at Rima Bode and Sulpicius Gallus, which are similar to the pyroclastics northwest of the Taurus Littrow valley (Apollo 17 site). Thus, exploration of the Aristarchus plateau would allow investigation of previously uncharacterized materials, whereas Rima Bode or Sulpicius Gallus would allow comparison to Apollo 17 pyroclastics. Any of these sites would enable evaluation of reported H2O/OH in these deposits. Second, we examined a possible site for a direct ISRU demonstrator mission. For a stand-alone end-to-end (E2E) ISRU demonstrator, a fuller understanding of the physical and compositional characteristics of potential feedstock is required for mission risk reduction. In this case, locations near preexisting sites would allow extrapolation of ground truth to nearby deposits. Because a Ti-rich pyroclastic deposit appears advantageous from beneficiation and compositional perspectives, we examine an example E2E demo site northwest of the Taurus Littrow valley. Hydrogen and methane reduction, as well as the Fray–Farthing–Chen Cambridge process, could be tested there.

NASA Prepares To Drill for the “Oil of Space”

“We’re going to the Moon, and we’re going there to stay this time,” has become a NASA mantra as the US competes with other countries, including China and Russia (https://jpt. spe.org/esa-roscosmos-to-mine-oxygen-water-from-moon-rocks-as-nasa-eyes-first-artemis-lunar-mission), to be the first to put humans on the Moon and Mars. The race will rely heavily on using resources available on the planetary bodies - or in-situ resource utilization (ISRU). Chief among these is water, which has been called “the oil of space.” As NASA prepares for Artemis mission astronauts to land on the Moon in 2024, it will fly at least two preliminary missions to look for water and gather information about the lunar south pole. The Polar Resources Ice-Mining Experiment (PRIME-1) and Volatiles Investigating Polar Exploration Rover (VIPER) missions, which will be launched in late 2022 and 2023, respectively, will be the first missions to study ISRU on another celestial body. They will also mark the first time NASA will robotically sample and analyze for ice from below the surface. And they will use technologies transferred and adapted from oil and gas exploration. Reconnaissance Missions Data from nearly 3 decades of lunar orbiter and impactor missions suggest that the Moon’s “soils,” particularly at its south pole and other regions, could contain hundreds of millions of gallons of water that could eventually be harvested and converted to oxygen, fuel, or drinkable water for human use on the Moon, Mars, and beyond. But, at what concentrations? In what kinds of soils? And is the water in a form that’s accessible? Most of the information we have about the presence of water-ice on the Moon comes from orbital measurements. The only direct evidence acquired to date came in 2009 from a sensing satellite aboard a spacecraft that was purposely crashed in the Cabeus crater. The material ejected as a result of the impact was analyzed with a spectrometer to reveal the presence of 5.6%±2.9% water-ice by mass. The form, distribution, composition, and quantity of the water-ice remain largely uncertain. The only way to reduce this uncertainty is to obtain ground-truth data by drilling exploratory boreholes in the crater. This will be the purpose of the PRIME-1 and VIPER missions. PRIME-1 will last a week to 10 days, during which a robot will deploy a drill and mass spectrometer to harvest and preliminarily evaluate moon-ice for quality and regional heights and to determine how much of the ice is lost to a process known as sublimation, wherein the water transforms directly from solid ice into vapor, rather than first going through a liquid phase. In addition to ice, PRIME-1 will gather samples including rock samples to help date the sequence of impact events on the Moon, core tube samples to capture ancient solar wind trapped in regolith layers (unconsolidated, inorganic rocky material), and paired samples of material to characterize the presence of volatiles and to assess geotechnical differences between materials inside and outside permanent shadows. The samples will be returned to Earth and studied to characterize and document the regional geology, including the small, permanently shadowed regions. The data from the mission will help scientists understand how a mobile robot to be used on the subsequent VIPER mission can search for water at the Moon’s pole, and how much water may be available to use as NASA plans to establish a sustainable human presence on the Moon by the end of the decade (Fig. 1).

Characterization of H2O transport through Johnson Space Center number 1A lunar regolith simulant at low pressure for in-situ resource utilization

H2O transport through a packed bed of Johnson Space Center number 1A (JSC-1A) lunar regolith simulant was examined at relevant temperatures and pressures for in-situ resource utilization (ISRU) on the Moon. Experimentation was conducted over a range of pressures from 50 to 2065 Pa at ∼350 K, corresponding to Knudsen numbers of 0.3 < Kn < 11. Pressure and temperature conditions were relevant toward ISRU technologies. A piecewise function was used to evaluate transition and Knudsen regime flows. The piecewise model utilized a Knudsen number that predicted the transition point between advective and Knudsen flows. A transition Knudsen number of 1.66 ± 0.61 and a tortuosity shape parameter of 0.736 ± 0.13 were determined from non-linear regression, and Knudsen diffusivities of 10.62 cm2·s−1, 10.40 cm2·s−1, and 9.04 cm2·s−1 for packed beds of JSC-1A with porosities of 0.388, 0.385, and 0.365, respectively. The experimental measurements, methodology, and modeling provide useful information for ISRU technologies involving the transport of volatiles (e.g., thermal extraction of H2O).

Potential resources on 6 Hebe asteroid

6 Hebe located in the main asteroid belt is one of the potential extraterrestrial objects of future mining exploitation. It is also widely recognized as the parent body of H chondrites. Based on the chemical analyses of H chondrites, the average chemical composition of the asteroid was determined. This asteroid is composed of, among others [in Mg]: Fe (3.54 · 1015), Ni (2.17 · 1014), Cr (4.44 · 1013), Co (1.05 · 1013), Cu (1.19 · 1012), Mo (1.78 · 1010). These elements are a component of various minerals, including minerals that can be a future object of exploitation. Primarily, they are FeNi alloy minerals, but also e.g. chromite. The reserves of these elements are smaller, but assuming that it is 10 or even 1% of resources, they are still huge. The reserves of 6 Hebe can cover Earth’s demand for selected elements for several thousand to even several million years. For comparison, with the current mining production of iron, the earth’s resources will last 153 years, and reserves–56 years [1]. Extraterrestrial mining may in the future be an ecological alternative to mining on Earth.

A solar thermal storage power generation system based on lunar in-situ resources utilization: modeling and analysis

Continuous energy supply is crucial to the crew and assets of lunar outposts during the darkness lunar night of 350 h in the long term lunar exploration. A solar energy storage power generation system based on in-situ resource utilization (ISRU) is established and analyzed. An efficient linear Fresnel collector is configured for solar concentration. The thermal energy reservoir (TER) coupling with Stirling power generator is designed using the fuel tanks of descent module and lunar regolith. A comprehensively theoretical model based on finite time thermodynamics is developed to analyze the energy flow and efficiency of thermal storage power generation system, and the major irreversibilities are taken into account. The results show that the designed system can produce an average power of 6.5 kW during the lunar night with 19.6% utilization efficiency of collected solar energy in the daytime. The evaluated launch mass of designed power system has a competitive advantage than those of nuclear reactor power and photovoltaic-battery power systems. The influences of major heat transfer processes including heat leakage of TER, heat exchange capability of Stirling engine and radiator are also discussed, which provides physical insight for optimal design of future power generation system based on ISRU.

Our Contribution to the NASA RASSOR Bucket Drum Design Challenge

NASA’s Artemis program aims to return humans to the Moon sustainably and efficiently by using new and improved technology, which is based on the concept of generating products with local materials, a practice called In Situ Resource Utilization (ISRU). Regolith excavation is the fundamental step in the ISRU chain to produce local commodities, such as propellants and breathing air, and to pursue construction operations. NASA is currently working on the Regolith Advanced Surface Systems Operations Robot (RASSOR), the key technology to enable extraterrestrial mining. The robot uses counterrotating bucket drums that capture regolith and keep it from falling out. NASA reached out to the public via GrabCAD to improve the robot’s design and chose five concepts, which will be tested and further improved. A team of three students from the University of Leoben (Dominik Höber, Andreas Taschner, and Stephan Weißenböck) took part in the challenge set by NASA and shared their ideas and concepts. They used this opportunity to implement their acquired knowledge from their studies and were also supported by a researcher from the Chair of Mining Engineering of the University of Leoben—Eric Fimbinger. The final design consists of three significant elements that were fused to increase efficiency: An outer helix, a spiral tunnel, and an inner helix. These three important components make up the concept which impressed the jury and reached fourth place out of approx. 350 entries. Due to the success of the project as well as the aroused interest amongst the students, further research projects were initialised as follow-ups, dealing with the topic of extraterrestrial mining. One is a research and development study covered by two master’s theses about excavation and conveying concepts on the Moon (see the article by Höber, Taschner and Fimbinger in this issue). The other one is in the form of a bachelor’s thesis to compare and analyse chosen concepts from the design challenge in a numerical simulation environment with equal conditions to allow virtual testing of those chosen designs.

Regolith as substitute mold material for aluminum casting on the Moon

ESA, NASA, and other space institutions are planning the return to the Moon. In the next decades, a human outpost on the lunar surface is going to be established to extend the opportunities for science and economy. For this project, new materials, methods, and processes based on In-Situ Resource Utilization (ISRU) are needed. One aspect is the casting of metals to produce tools, construction elements, or infrastructure, which are to frail or too large to be transported with a rocket. Earth-based manufacturing relies on sand-casting or permanent mold casting processes. These could be adapted for Moon manufacturing with lunar regolith. Regolith can be shaped and/or sintered to produce a mold similar to sand-casting or permanent mold casting. This paper presents results from first experiments carried out by TU Braunschweig and Orbit Recycling with aluminum, Al-alloys and the regolith simulant TUBS-M. It is shown that it is possible to cast a wide range of aluminum parts using lunar regolith. Using a permanent mold, it was possible to achieve multiple casts from one mold. Thus, new ISRU based adapted processes for lunar manufacturing could be possible.

ISRU technology deployment at a lunar outpost in 2040: A Delphi survey

The purpose of this study was to deploy a Delphi expert elicitation methodology to better understand the technical and policy challenges facing the development of a sustainable lunar outpost in 2040, including the types and scale of In-Situ Resource Utilisation (ISRU) deployment. We used a three-round Delphi survey with an open first round and specific questions in later rounds using a four-point Likert scale and two ranking exercises to assess energy technologies and inhibiting factors. In order to provide more certainty to our potential participants regarding their input, and boost engagement, the study deployed a three-round approach that was communicated to our potential participants and decided ex-ante. Potential participants were identified from the literature and academic networks as those who had made significant contributions to the fields of: ISRU technologies, space architecture, space-qualified power systems, and space exploration. The study identified around 20 major themes of interest for researchers in the first round and asked participants to rate their agreement with a number of statements about a hypothetical lunar outpost in 2040. From the group responses, we identified three major technical challenges for the development of a lunar outpost in 2040; developing high power energy infrastructure, lander and vehicle ascent capacity, and mission architectures and technical approaches. We also identified three major policy challenges for the development of a lunar outpost in 2040: (i) US and global political instability, (ii) possibility of an extended timeframe for the first lunar landing, and (iii) political distaste for nuclear energy in space. The group was uncertain about the precise energy mix at the outpost as a result of uncertainty regarding electrical loads, but there was general agreement that solar PV would be a significant contributor. Whether nuclear power sources might play a useful role proved to be very uncertain, with some participants noting a political distaste for space nuclear power systems. However, the proposition gained two votes in each ranking position, suggesting it has a flat distribution including both supporters and detractors.

Experimental characterization of lithium-carbon dioxide combustion in batch reactors for powering Venus landers

The extreme environment and low solar availability on the surface of Venus translate to significant power and thermal management challenges for landed missions. The longest mission to the surface of Venus was Venera 13, which operated for ~2 h. To increase duration and scientific scope, future missions will require power systems with greater specific energy to support active cooling. In-situ resource utilization (ISRU) combustion power systems have been proposed with lithium fuel and the ambient atmosphere (96.5% CO2, 3.5% N2) as the oxidizer. Conceptual designs have assumed batch reactors, which may vary in behavior as fuel is consumed and product concentration increases. As such, practically achievable reaction yield and system-specific energy are unknown. In this study, Li-CO2 batch combustion tests were performed to determine such reaction parameters. Five tests were performed with different operating temperatures, heat delivery mechanisms, and approaches for contacting fuel and oxidizer. Fuel utilization was found to generally increase with bulk reactor temperature. At 500–750 °C, fuel utilization was only 40–60%. This increased to ~98% at 900 °C, corresponding to an effective specific energy of 25.6 ± 0.7 MJkgLi−1 based on reactant and product enthalpies. However, endothermic decomposition of produced Li2CO3 occurs at higher temperatures, limiting specific energy. Based on fuel utilization, the lower temperature cases achieved 32–41 MJkgLi,reacted−1. Attempts to increase lower temperature reaction yield were unsuccessful in this investigation. Further development of approaches to improve yield could enhance the technical potential of lithium combustion power systems.

Mars Oxygen ISRU Experiment (MOXIE)

MOXIE is a technology demonstration that addresses the Mars 2020 (Perseverance) objective of preparing for future human exploration by demonstrating In Situ Resource Utilization (ISRU) in the form of dissociating atmospheric CO2 into O2. The primary goals of the MOXIE project are to verify and validate the technology of Mars ISRU as a springboard for the future, and to establish achievable performance requirements and design approaches that will lead to a full-scale ISRU system based on MOXIE technology. MOXIE has three top-level requirements: to be capable of producing at least 6 g/hr of oxygen in the context of the Mars 2020 mission (assuming atmospheric intake at 5 Torr, typical of Jezero Crater, and $0~^{\circ}\text{C}$ , typical of the rover interior); to produce oxygen with $>98\%$ purity; and to meet these first two requirements for at least 10 operational cycles after delivery. Since MOXIE is expected to operate in all seasons and at all times of day and night on Mars, these requirements are intended to be satisfied under worst-case environmental conditions, including during a dust storm, if possible.

Continuous microfluidic solvent extraction of cobalt from mimicked and real asteroid leaching solutions

This research proposes a pathway for the last step of the asteroid mining process: the purification of the adjacent metals, cobalt and nickel, in the frame of in-situ resource utilization (ISRU) in space. Major technological and economic challenges will need to be overcome, and one main issue to be tackled is the reduction of water usage in this process. Therefore, the leached metal solutions are expected to contain ultra-high metal concentrations, up to 10 mol/l. These solutions will have challenging thermodynamic properties (increased density, viscosity and interfacial tension). As a result, an analysis of dimensionless numbers for fluidics and mass transport was made, showing that some of these are favourable under the constraints of accessible microfluidic operations. Experiments were performed with advanced microfluidic reactors (a coiled-flow inverter (CFI) and an industrial re-entrance flow reactor from Corning®) at high metal concentrations and high nickel to cobalt ratios (3:0.3 mol/l Ni:Co). Using Cyanex 272 as a selective extractant for cobalt, extraction efficiencies of 60% with high separation factors (>1000) were reached in just one extraction stage. The CFI showed high extraction efficiency for low fluid velocities and a residence time of 60 s. For the Corning® reactor, high fluid velocities or the use of many modules (>3) are needed to obtain an emulsion, resulting in high extraction efficiencies at a very short residence time of 13 s. The comparison between the CFI and the Corning® reactor shows that they share the best operation point (at 120 ml/h), but the Corning® reactor performs better at higher flow rates and thus can leverage higher productivity. However, the CFI is easier to operate and has a much lower pressure drop, resulting in low energy input. Finally, an iron meteorite sample was leached and efficiently extracted in both microfluidic reactors.

Continuous-Flow Extraction of Adjacent Metals-A Disruptive Economic Window for In Situ Resource Utilization of Asteroids?

For the in situ resource utilization (ISRU) of asteroids, the cost-mass conundrum needs to be solved, and technologies may need to be conceptualised from first principals. By using this approach, this Review seeks to illustrate how chemical process intensification can help with the development of disruptive technologies and business matters, how this might influence space-industry start-ups, and even industrial transformations on Earth. The disruptive technology considered is continuous microflow solvent extraction and, as another disruptive element therein, the use of ionic liquids. The space business considered is asteroid mining, as it is probably the most challenging resource site, and the focus is on its last step: the purification of adjacent metals (cobalt versus nickel). The key economic barrier is defined as the reduction in the amount of water used in the asteroid mining process. This Review suggests a pathway toward water savings up to the technological limit of the best Earth-based processes and their physical limits.

Exploiting a perchlorate-tolerant desert cyanobacterium to support bacterial growth for in situ resource utilization on Mars

AbstractThe presence of perchlorate in the Martian soil may limit in-situ resource utilization (ISRU) technologies to support human outposts. In order to exploit the desiccation, radiation-tolerant cyanobacterium Chroococcidopsis in Biological Life Support Systems based on ISRU, we investigated the perchlorate tolerance of Chroococcidopsis sp. CCMEE 029 and its derivative CCMEE 029 P-MRS. This strain was obtained from dried cells mixed with Martian regolith simulant and exposed to Mars-like conditions during the BIOMEX space experiment. After a 55-day exposure of up to 200 mM perchlorate ions, a tolerance threshold value of 100 mM perchlorate ions was identified for both Chroococcidopsis strains. After 40-day incubation, a Mars-relevant perchlorate concentration of 2.4 mM perchlorate ions, provided as a 60 and 40% mixture of Mg- and Ca-perchlorate, had no negative effect on the growth rate of the two strains. A proof-of-concept experiment was conducted using Chroococcidopsis lysate in ISRU technologies to feed a heterotrophic bacterium, i.e. an Escherichia coli strain capable of metabolizing sucrose. The sucrose content was fivefold increased in Chroococcidopsis cells through air-drying and the yielded lysate successfully supported the bacterial growth. This suggested that Chroococcidopsis is a suitable candidate for ISRU technologies to support heterotrophic BLSS components in a Mars-relevant perchlorate environment that would prove challenging to many other cyanobacteria, allowing a ‘live off the land’ approach on Mars.

Spark plasma sintering of a lunar regolith simulant: effects of parameters on microstructure evolution, phase transformation, and mechanical properties

The spark plasma sintering (SPS) process is a potentially effective in-situ resource utilization (ISRU) technology for consolidating lunar regolith in order to produce structural components for future space exploration. This study examined the fundamental mechanisms of the effects of SPS conditions on microstructure evolution, phase transformation, and mechanical properties. For this purpose, a lunar regolith simulant (FJS-1) was selected and sintered for a total of 16 cases based on four primary SPS testing parameters: temperature, applied external pressure, dwell time, and heating rate. The Taguchi design method was used to examine the effects and sensitivity of each testing parameter. Laboratory tests were conducted in multiple length scales, including density, porosity, optical microscopy, scanning electron microscopy aided by energy-dispersive spectroscopy, transmission electron microscopy, nanoindentation, and strength testing (in both compressive and flexural). Taguchi analysis results of SPS parameters and sintering mechanism discussion indicated that the sintering temperature is the dominant factor changing microstructure heterogeneity and densification during the SPS process. The contribution of applied pressure to the surface and the grain boundary diffusion rate and the nucleation rate indicated that the applied pressure may have enhanced both phase transformation and homogeneity during the sintering process. Strength of the sintered samples were approximately 10 times greater than those of a typical plain concrete. The collective results indicate that the SPS technology, a potentially viable ISRU method, can be used to produce property-specific and application-targeted building components on the lunar surface.

Influence of Powder Type on Aerosol Emissions in Powder-Binder Jetting with Emphasis on Lunar Regolith for In Situ Space Applications

Powder-binder jetting is an additive process with applications for manufacturing complex geometric structures, such as lightweighting, mold making, and in situ resource utilization (ISRU) for space...

Challenging the agricultural viability of martian regolith simulants

As human space exploration extends farther from Earth, the cost and risk of resupplying a mission increases substantially. In situ resource utilization (ISRU) is the prospecting, extraction, storage, and exploitation of existing resources at the crew location, reducing cost and risk. Crucial to the development of ISRU solutions is the accurate characterization and modeling of regolith for a variety of applications, including as a substrate for food production at lunar or Martian sites. Previous studies have established the capacity of specific regolith simulants to support the growth of a variety of plants in the short term. However, the mineralogical and physical accuracy of these simulants as proxies for the sites on Mars is debatable, and any conclusion drawn from studies with these simulants must be considered with some degree of caution. For the purpose of studying ISRU food production, we present a systematic effort to evaluate the utility of three different Martian Regolith Simulants (MRSs): JSC-Mars-1A, Mars Mojave simulant (MMS), and Mars Global simulant (MGS-1). Our findings confirmed that none of these simulants are capable of supporting plant growth in the absence of nutrient supplementation. However, with the addition of a nutrient supplement, both JSC-Mars-1A and MMS were able to support the growth of both Arabidopsis thaliana and Lactuca sativa. However, the highly alkaline (pH > 9.0) MGS-1 simulant was unable to support growth even with additional nutrients. Acidification of MGS-1 nearly doubled the longevity of plants grown in this medium, suggesting this simulant may be further modified to eventually support plant growth as well. The addition of calcium perchlorate to each simulant, at concentrations intended to mimic those observed on the surface of Mars, rendered each simulant incapable of supporting plant growth, regardless of nutrient supplementation. These findings underscore that ISRU food solutions are likely at a lower technological readiness level than previously thought. We discuss these findings in the context of future efforts to develop off-world agricultural systems, approaches to developing future MRSs, and the immediate need to address perchlorate contamination as well as nitrogen deficiency for regolith-based food production.

A Flexible Lunar Architecture for Exploration (FLARE) supporting NASA's Artemis Program

The Flexible Lunar Architecture for Exploration (FLARE) is a concept to deliver four crew to the lunar surface for a minimum of seven days and then return them safely to Earth. FLARE can be implemented whenever the component vehicles are operational. FLARE was developed as an alternative to NASA's Human Landing System (HLS) reference architecture from the Design Analysis Cycle (DAC) #2 created in 2019. The DAC2 guidelines required utilization of the Gateway vehicle in a Near- Rectilinear Halo Orbit (NRHO). Instead, FLARE chooses a Low Lunar Frozen Polar Orbit (LLFPO) for lunar rendezvous of components, and an optional Gateway vehicle. The LLFPO provides a stable orbit that overflies the south pole every 2 h, ensuring easy access to the lunar surface for surface aborts with a much lower propellant requirement than NRHO. The minimum FLARE concept uses one Space Launch System (SLS) launch, one Orion, one European Service Module (ESM), and one human lander (launched on commercial vehicle(s)). FLARE adds the SpaceTug, based upon the mature and successful ULA “Common” Centaur Upper Stage vehicle, with modifications to create an Earth-Moon transfer vehicle. In the FLARE baseline mission, the SpaceTug provides propulsion needed to return the Orion + ESM from LLFPO to Earth. The SpaceTug also provides propulsion to deliver the separate human lander components – the Descent Element (DE) and the Ascent Element (AE) - from Low Earth Orbit (LEO) to LLFPO. The SLS Block 1 then launches the Orion + ESM and completes a rendezvous with the mated DE + AE components in LLFPO. FLARE offers optional phases beyond the baseline mission. The SpaceTug can deliver components of the planned Gateway, including the Power and Propulsion Element (PPE) and the Habitable and Logistics Outpost (HALO), to LLFPO. FLARE provides an option to deliver precursor equipment to the lunar surface to enhance and extend the human mission. With these components, including an inflatable habitation module and airlock, individual crew mobility vehicle(s), an In-Situ Resource Utilization (ISRU) demonstration, and science and technology experiments, the crew can explore and conduct science on the lunar surface for up to 14 days.