Assessment of the early stages of rehydration observed by sorption isotherm and 1H-NMR and plant growth tests for Martian regolith simulant MGS-1

Volcanic soils cover 1% of the Earth’s surface but support 10% of the world’s population. They are among the most fertile soils in the world, due to their excellent physical properties and richness in available nutrients. The major limiting factor for plant growth in volcanic soils is phosphate fixation, which is mainly attributable to active species of aluminium and iron. The sorption and desorption of phosphate is studied on the surface horizons of two African agricultural soils, a silandic Andosol (Rwanda) and a vitric Andosol (São Tomé and Principe). Both soils are slightly acid. The silandic Andosol is rich in active aluminium forms, while the vitric Andosol has high amounts of crystalline iron and aluminium oxides. Sorption isotherms were determined by equilibrating at 293K soil samples with phosphate solutions of concentrations between 0 and 100 mg P L−1 in NaNO3; phosphate was determined by visible spectrophotometry in the equilibrium solution. To study desorption, the soil samples from the sorption experiment were equilibrated with 0.02 M NaNO3. The isotherms were adjusted to mathematical models. In almost all the concentration range, the adsorption of phosphate by the silandic Andosol was greater than 90% of the amount added, being lower in the vitric Andosol but always higher than 65%. The high sorption by the silandic Andosol is attributed to its richness in non-crystalline Fe and Al, while in the vitric Andosol crystalline iron species seem to play a relevant role in the adsorption. The sorption isotherms of both soils fitted to the Temkin model, the adjustment to the Langmuir or Freundlich models being unsatisfactory; throughout the range studied, the sorption increases with increasing phosphorus concentration, a maximum sorption is not predictable (as occurs when the sorption is adjusted to the Langmuir model). For an added P concentration of 100 mg L−1 (3.2 mmol L−1), the sorption is 47.7 µmol P g−1 in the silandic Andosol and 41.6 µmol P g−1 in the vitric Andosol. The desorption is low and the comparison of the sorption and desorption isotherms reveals a pronounced hysteresis, that is, the irreversibility of the sorption. The high phosphate sorption and its irreversibility are comparable to those published for other volcanic soils with high contents of allophane, active aluminium and free iron. The strong phosphate adsorption is a serious limiting factor for plant growth, which requires a careful management of phosphorus fertilization.

Perchlorate (ClO4−) is globally enriched in Martian regolith at levels commonly toxic to plants. Consequently, perchlorate in Martian regolith presents an obstacle to developing agriculture on Mars. Here, we assess the effect of perchlorate at different concentrations on plant growth and germination, as well as metal release in a simulated Gusev Crater regolith and generic potting soil. The presence of perchlorate was uniformly detrimental to plant growth regardless of growing medium. Plants in potting soil were able to germinate in 1 wt.% perchlorate; however, these plants showed restricted growth and decreased leaf area and biomass. Some plants were able to germinate in regolith simulant without perchlorate; however, they showed reduced growth. In Martian regolith simulant, the presence of perchlorate prevented germination across all plant treatments. Soil column flow-through experiments of perchlorate-containing Martian regolith simulant and potting soil were unable to completely remove perchlorate despite its high solubility. Additionally, perchlorate present in the simulant increased metal/phosphorous release, which may also affect plant growth and biochemistry. Our results support that perchlorate may modify metal availability to such an extent that, even with the successful removal of perchlorate, Martian regolith may continue to be toxic to plant life. Overall, our study demonstrates that the presence of perchlorate in Martian regolith provides a significant challenge in its use as an agricultural substrate and that further steps, such as restricted metal availability and nutrient enrichment, are necessary to make it a viable growing substrate.

The initial stages of rehydration of digalactosyldiacylglycerol model membrane lyophilizates were observedusing hydration kinetics, sorption isotherm, and high power proton relaxometry (at 30 MHz). Hydration timecourses are single exponential and the sorption isotherm is sigmoidal in form. The mass of water saturating primarybinding sites equals ¢

The initial stages of rehydration of salmon sperm deoxyribonucleic acid (DNA) lyophilizates were observed using hydration kinetics, sorption isotherm, and high power proton relaxometry (at 30 MHz). The hydration kinetics reveals (i) a very tightly bound water not removed by incubation over silica gel (A0 = 0.057±0.010), (ii) a tightly bound water [saturating at A1 = 0.149± 0.007, hydration time t1 = (0.27± 0.08) h], a tightly bound water (iii) [saturating at A2 = 0.694± 0.039, with the hydration time t2 = (9.8± 3.2) h], and (iv) a loosely bound water fraction for the samples hydrated at p/p0 ≥ 76% [with the hydration time t3 = (44± 14) h, and the contribution progressively increasing with the air humidity]. For the hydration at p/p0 = 100%, after t0 = (244 ± 22) h of incubation the swelling process begins. The amount of additional water uptake at swelling depended on the macrostructure of the sample. Sorption isotherm is sigmoidal in form and is fitted well by the Dent model with the mass of water saturating primary binding sites ∆M/m0 = 0.114. Proton free induction decay is a superposition of the immobilized proton signal (Gaussian, with T ∗ 2S ≈ 20 μs) and two liquid signal components coming from tightly bound (T ∗ 2L1 ≈ 100 μs, with the mass saturating at ∆m/m0 = 0.111 ± 0.044) and loosely bound water fraction (with the amplitude proportional to the mass of water added).

Bioprinting, a technology with the potential to support long-term space missions, offers medical solutions for human settlements on the Moon and Mars. Moreover, 'green bioprinting' presents a promising approach to address terrestrial environmental challenges. Effective and cost-efficient implementation of this technology beyond the Earth requires leveragingin situresources on celestial bodies. Consequently, this study examines the integration of Lunar and Martian regolith into bioprintable hydrogels as mechanically stabilizing and protective components as well as nutrient sources. Hydrogel blends composed of alginate and methylcellulose were supplemented with regolith simulants. Rheological characterization revealed maintenance of shear thinning and shear recovery properties, ensuring optimal printability. In regards to cultivation of microalgae, the ion release/uptake of the regolith simulants in culture medium was investigated, indicating that regolith has potential to serve as nutrient source. The microalgaChlorella vulgarisand bacteriaButtiauxella sp. MASE-IM-9 andSalinisphaera shabanensiswere bioprinted in regolith-based inks. Results demonstrate that the microalgae maintained their photosynthetic efficiency in regolith-containing bioinks during cultivation, exhibiting high viability and growth. The bacteria exhibited an enhanced resistance to desiccation as well as temperature and radiation stress when regolith simulants were present in the hydrogels. This study confirms the feasibility of employing Lunar and Martian regolith simulants in bioinks for green bioprinting and bacterial bioprinting. Such an approach could minimize the volume of stored printing materials and culture media, optimizing rocket transport capacity.

Thermite reactions with oxides of iron and silicon during combustion of magnesium with lunar and Martian regolith simulants

A molecular study of Italian ryegrass grown on Martian regolith simulant

Bioregenerative life support systems (BLSS) are conceived of and developed so as to provide food sources for crewed missions to the Moon or Mars. Thein situresource utilization (ISRU) approach aims to reduce terrestrial input into a BLSS by using native regoliths and recycled organic waste as primary resources. The combination of BLSS and ISRU may allow sustainable food production on Moon and Mars. This task poses several challenges, including the effects of partial gravity, the limited availability of oxygen and water, and the self-sustaining management of resources. Lunar and Martian regoliths are not available on Earth; therefore, space research studies are conducted on regolith simulants that replicate the physicochemical properties of extra-terrestrial regoliths (as assessedin situby previous missions). This review provides an overview of the physicochemical properties and mineralogical composition of commercially available Lunar and Martian regolith simulants. Subsequently, it describes potential strategies and sustainable practices for creating regolith simulants akin to terrestrial soil, which is a highly dynamic environment where microbiota and humified organic matter interact with the mineral moiety. These strategies include the amendment of simulants with composted organic wastes, which can turn nutrient-poor and alkaline crushed rocks into efficient life-sustaining substrates equipped with enhanced physical, hydraulic, and chemical properties. In this regard, we provide a comprehensive analysis of recent scientific works focusing on the exploitation of regolith simulant-based substrates as plant growth media. The literature discussion helps identify the main critical aspects and future challenges related to sustainable space farming by thein situuse and enhancement of Lunar and Martian resources.

Development of martian regolith and bedrock simulants: Potential and limitations of martian regolith as an in-situ resource

Polymer seals are utilized in various engineering applications to prevent leakage and contamination. The study investigates the wear and friction behavior of PTFE-based dynamic rotary seals, targeting their usage in space applications. Pin-on-disc dry sliding wear tests were performed with 0.5 MPa contact pressure and 0.2 m/s sliding velocity combining different lip seal (PTFE, PTFE+GF+MoS2), packing (PTFE, PTFE+Aramid fiber+solid lubricant) and shaft materials (34CrNiMo6, PEEK) involving third-body lunar (LHS-1) and Martian regolith (MGS-1) simulants. To understand the different influences of extraterrestrial regolith simulants compared to commonly encountered abrasives on Earth, quartz sand was selected as a reference. Quartz soil resulted in lower wear rates but a similar coefficient of friction to other regoliths. In the case of lip seals, testing with LHS-1 on PEEK and testing with MGS-1 on steel resulted in the most severe wear. Post-mortem surface analysis revealed the effect of external abrasive particles on the wear process and the transfer layer formation. The surface analysis confirmed that both lunar and Martian regolith simulants resulted in significant embedded particles. Based on the wear performance results, the lip seals performed better, but installation with an external packing could further aid the tribosystem.

The search for life elsewhere in the Universe goes together with the search for liquid water. Life as we know it requires water; however, it is possible for microbial life to exist under hyperarid conditions with a minimal amount of water. We report on the ability of two typical terrestrial bacteria (Escherichia coli B and Eucapsis sp) and two extremophiles (Gloeocapsa-20201027-1 sp and Planococcus halocryophilus) to grow and survive in three martian soil (regolith) simulants (Mohave Mars Simulant-1 [MMS-1] F, Mars Global Simulant-1 [MGS-1], and JSC Mars-1A [JSC]). Survival and growth were assessed over a 21-day period under terrestrial conditions and with water:soil (vol:wt) ratios that varied from 0.25:1 to 5:1. We found that Eucapsis and Gloeocapsa sp grew best in the simulants MMS and JSC, respectively, while P. halocryophilus growth rates were better in the JSC simulant. As expected, E. coli did not show significant growth. Our results indicate that these martian simulants and thus martian regolith, with minimal or no added nutrients or water, can support the growth of extremophiles such as P. halocryphilus and Gloeocapsa. Similar extremophiles on early Mars may have survived to the present in near-surface ecological niches analogous to those where these organisms exist on Earth.

Introduction A key element for sustainable off-world habitation is the ability to grow food through in-situ resource utilization (ISRU). Growth substrates are required to overcome the challenges of ISRU in the space environment, including the use of regolith. Biofertilizers such as algae are a promising avenue for supporting plant growth with ISRU; algae can potentially mitigate the lack of nutrients, alkalinity, heavy-metal contamination, poor water-carrying capacity, and presence of perchlorates in regolith as well as increase plant growth at elevated levels of atmospheric CO 2 . The blue-green cyanobacterium Arthrospira platensis is an ionizing radiation resistant strain with high temperature tolerance and nutritional properties. It has been used successfully as a bio-fertilizer in heavy metal contaminated, highly alkaline terrestrial soils Methods Our research is a large-scale investigation of the efficacy of spirulina to enhance the growth of Raphanus sativus (Organic Daikon radish) microgreens using lunar and Martian regolith simulants. We present a study of growth for a wide range of regolith simulant-soil mixtures as a function of fertilizer concentration and the level of environmental CO 2 . Results Spirulina boosts growth for radish microgreens significantly; Martian regolith simulant with 0.6% spirulina under elevated CO 2 yielded the best results. Water-only groups declined after the initial growth phase; spirulina fertilized groups maintained steady growth rates over the full growing period. Regolith simulant type influenced biomass more than height, with the best growth found in Martian rather than lunar regolith simulant. No difference was found between the different regolith simulant-to-soil mixtures. Discussion This research advances the application of ISRU to enhance self-sufficient, sustainable space exploration and resource use. In this research, spirulina fertilization compensated for the non-nutritive properties of regolith, supporting plant growth without the addition of terrestrial soils. This work suggests that spirulina can serve as an effective biofertilizer in soil farming practices using ISRU as a potential means of supporting off-world habitation.

Ecotoxicological tests assessment of soils polluted by chromium (VI) or pentachlorophenol.

Mechanical behavior of the metal parts welded with extraterrestrial regolith simulant by the solar concentrator in ISRU & ISRF application

The analysis of the organic compounds present in the martian regolith is essential for understanding the history and habitability of Mars, as well as studying the signs of possible extant or extinct life. To date, pyrolysis, the only technique that has been used to extract organic compounds from the martian regolith, has not enabled the detection of unaltered native martian organics. The elevated temperatures required for pyrolysis extraction can cause native martian organics to react with perchlorate salts in the regolith and possibly result in the chlorohydrocarbons that have been detected by in situ instruments. Supercritical carbon dioxide (SCCO2) extraction is an alternative to pyrolysis that may be capable of delivering unaltered native organic species to an in situ detector. In this study, we report the SCCO2 extraction of unaltered coronene, a representative polycyclic aromatic hydrocarbon (PAH), from martian regolith simulants, in the presence of 3 parts per thousand (ppth) sodium perchlorate. PAHs are a class of nonpolar molecules of astrobiological interest and are delivered to the martian surface by meteoritic infall. We also determined that the extraction efficiency of coronene was unaffected by the presence of perchlorate on the regolith simulant, and that no sodium perchlorate was extracted by SCCO2. This indicates that SCCO2 extraction can provide de-salted samples that could be directly delivered to a variety of in situ detectors. SCCO2 was also used to extract trace native fluorescent organic compounds from the martian regolith simulant JSC Mars-1, providing further evidence that SCCO2 extraction may provide an alternative to pyrolysis to enable the delivery of unaltered native organic compounds to an in situ detector on a future Mars rover. Biomarkers-Carbon dioxide-In situ measurement-Mars-Search for Mars' organics. Astrobiology 16, 703-714.