Profiling lunar dust dissolution in aqueous environments: The design concept

There has been an exponential increase in planned lunar missions with the advent of commercial missions and future manned missions. Understanding the lunar environment is crucial to providing information for future missions that will land on the moon and other celestial bodies. The necessity to navigate freely, without loss of sensing capability is paramount to many of these explorations. Some of the vehicles that will pioneer these missions will encounter various natural hazards and awareness challenges–such as lunar dust and regolith. Due to their electrical and mechanical properties, the constituent particles will tend to adhere to the surface of the exploratory craft and the on-board equipment. This behavior poses a significant threat as the charged dust can cause vital electronics to short or render experimental instruments unusable due to accumulation and electrical discharges, as experienced by the Apollo crews on each visit to the Moon. This paper will focus on the design and experimentation of an autonomous control system that will detect regolith using the deep learning computer vision architecture MobileNetV2, and remove it using an electrodynamic dust shield covering a camera lens. This entire system provides an active method to detect optical obstructions, assess, and then remove them in order to regain navigation and/or scientific capabilities.

The establishment of a permanent lunar base is the goal of several space missions, such as NASA’s Artemis program. The feasibility of a lunar base is highly dependent on the supply of clean water, which can be recycled within the life support system or extracted in-situ on the Moon. Contamination of the water by lunar dust is an unavoidable problem due to the fact that lunar dust covers the entire surface and has adhesive properties as well as a very fine particle size. It is therefore important to study and characterise water contaminated by lunar dust in order to develop a safe water supply system. We combined existing studies on the dissolution behaviour of lunar regolith in aqueous solutions and performed dissolution experiments ourselves. We conducted dissolution experiments using the Lunar Highland Dust simulant from Exolith Lab (Orlando, United States), which resembles the Apollo 16 regolith and thus the terrain of the suspected Artemis landing sites. Our dissolution experiments investigate the effects of the dust to solution ratio, the aqueous solution used (ultrapure water and 5.5 buffer), the short exposure time (2 min up to 72 h), the dissolved oxygen in the solutions and the particle size of the simulant. As a result, this study provides a characterisation of lunar dust contaminated water and compares the results with the World Health Organization (WHO) and NASA requirements for drinking water. For all test batches, the lunar dust contaminated water exceeds the requirements for pH, turbidity and Al concentration.

The influence of surface roughness on volatile transport on the Moon

Abstract— Any permanent presence on the Moon will require use of materials from the lunar regolith, the surface soil layer on the Moon. Thus, knowledge of the thickness of the lunar regolith is essential. It has been proposed that crater counts obtained from high Sun angle photography give larger estimates of impact crater equilibrium diameters than for low Sun angle photography, and thus deeper estimates of lunar surface regolith than were previously made using crater morphology, size of blocky rimmed craters, and equilibrium diameters determined on low Sun angle images. The purpose of this comment is to evaluate this result as a means of resolving this important question before planning for future lunar missions is undertaken

CELSS transportation analysis

Protecting Lunar Colonies From Space Radiation

Indirect solar receiver development for the thermal extraction of H2O(v) from lunar regolith: Heat and mass transfer modeling

As future manned and robotic space explorations missions involve more complex systems, it is essential to verify, validate, and optimize such systems through simulation and emulation in a low cost testbed environment. The goal of such a testbed is to perform detailed testing of advanced space and ground communications networks, technologies, and client applications that are essential for future space exploration missions. We describe the development of new technologies enhancing our Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) that enable its integration in a distributed space communications testbed. MACHETE combines orbital modeling, link analysis, and protocol and service modeling to quantify system performance based on comprehensive considerations of different aspects of space missions. It can simulate entire networks and can interface with external (testbed) systems. The key technology developments enabling the integration of MACHETE into a distributed testbed are the Monitor and Control module and the QualNet IP Network Emulator module. Specifically, the Monitor and Control module establishes a standard interface mechanism to centralize the management of each testbed component. The QualNet IP Network Emulator module allows externally generated network traffic to be passed through MACHETE to experience simulated network behaviors such as propagation delay, data loss, orbital effects and other communications characteristics, including entire network behaviors. We report a successful integration of MACHETE with a space communication testbed modeling a lunar exploration scenario. This document is the viewgraph slides of the presentation.

Dust contamination is a serious problem for equipment and vehicles for space mission applications. Lunar "weathering" has left the lunar soil with a relatively fine texture, a small count median diameter and an unusually large geometrical standard deviation compared to terrestrial dust particle size distributions. Accumulated lunar dust regolith is estimated to reduce solar power system efficiencies by as much as 50 percent. Lunar dust is electrostatically charged, difficult to remove, and appears to get everywhere. Astronaut exposure to lunar dust and its risks to health and operations are also an important design consideration for long-duration lunar missions. We are attempting to design an integrated approach to solving the dust problems associated with its many elements (life support systems, EVA, docking and berthing, surface mobility, in situ resource utilization, and power system components), as opposed to leaving it to each individual element developer. Other potential applications include mitigation of unintentional capture of extraterrestrial bacteria or spores on the surfaces of the equipment. This presentation will present an overview of the lunar regolith particle size and shape distribution properties, hydrophilic and hydrophobic coating self-cleaning approaches and a new approach which incorporates various catalytic mechanisms (stoichiometric, photocatalytic and electrocatalytic) for decontamination.

Bioregenerative life support systems (BLSS) designed to produce food crops in future crewed missions to the Moon or Mars consider in-situ resource utilisation (ISRU). Lunar regolith is, therefore, in focus for future technologies of farming on lunar bases. We tested germination and early growth of broccoli plants ( Brassica oleracea var. botrytis italica ) in Murashige-Skoog liquid medium with addition of leachate from a lunar regolith simulant. As the additions to growth, differently diluted water and acidic leachates were used. Physiological status of the germinating plants was evaluated by chlorophyll fluorescence parameters related to plant vitality (relative fluorescence decline – Rfd) and photosynthetic performance of photosystem II (1) potential (F V /F M ) and (2) effective quantum yield of PSII (Φ PSII ), photochemical quenching referring to number of open PSII reaction centres. Both water and acidic leachates inhibited plant growth, however, the extent of growth limitation was dilution-dependent. Full inhibition of germination was apparent when undiluted acidic leachate was added. However, 50% dilution (and higher) resulted in seed germination and the early growth. No negative effects of the water dilutions on F V /F M as well as Φ PSII , were apparent in 15 days old plants, their cotyledonary and the first primary leaves, in particular. Similarly, qP and Rfd showed no sign of either water or acidic leachate addition effect. Although photosystem II-related parameters exhibited no negative effect of the leachates addition, a growth of plants was found dilution-dependent: higher degree of dilution resulted in a more pronounced reduction in plant projection area. In spite of the growth rate reduction (compared to untreated control), properly diluted water and acidic leachates from lunar regolith and/or its simulants might be used in follow up studies focused on plant species prospective for future cultivation in Moon-based stations with temporary or permanent crew.

In this study, we present a new quantification method for surface concentrations of lunar dust and lunar simulant. This technique demonstrates the use of portable X-ray fluorescence spectroscopy (pXRF) to quantify surface lunar dust loading on surfaces using an adaption of existing pXRF techniques and is the first demonstration of a high accuracy and precision tool designed to quantify lunar dust loading in-situ on large surfaces within seconds. This study shows the background in current methodologies for quantification of lunar dust in tests as well as current and potential future techniques for lunar surface missions, as well as current applications of commercial off-the-shelf (COTS) pXRF technology. The methodology for adapting current pXRF techniques is presented, followed by a demonstration of this new method on a variety of materials and test campaigns related to spaceflight or lunar surface missions. This technique shows high fidelity for immediate utilization as well as a demonstration of high potential for future surface missions. Potential current uses can include development and qualification testing, as well as requirement verification and validation. Included future work outlines calibration adjustments to make this technique more adaptable and hardware developments for eventually using this tool during lunar missions.

Initial studies of neutron spectrometer data returned by Lunar Prospector concentrated on the discovery of enhanced hydrogen abundances near both lunar poles. However, the nonpolar data exhibit intriguing patterns that appear spatially correlated with surface features such as young impact craters (e.g., Tycho). Such immature crater materials may have low hydrogen contents because of their relative lack of exposure to solar wind‐implanted volatiles. We tested this hypothesis by comparing epithermal* neutron counts (i.e., epithermal −0.057 × thermal neutrons) for Copernican‐age craters classified as relatively young, intermediate, and old (as determined by previous studies of Clementine optical maturity variations). The epithermal* counts of the crater and continuous ejecta regions suggest that the youngest impact materials are relatively devoid of hydrogen in the upper 1 m of regolith. We also show that the mean hydrogen contents measured in Apollo and Luna landing site samples are only moderately well correlated to the epithermal* neutron counts at the landing sites, likely owing to the effects of rare earth elements. These results suggest that further work is required to define better how hydrogen distribution can be revealed by epithermal neutrons in order to understand more fully the nature and sources (e.g., solar wind, meteorite impacts) of volatiles in the lunar regolith.

Integrated system health management (ISHM) technologies have been developed to address safety, replace time-based maintenance with condition-based maintenance, and to reduce life cycle costs. Traditional space system designs have focused on safety to minimize the risk to crew and to protect the public, astronauts and pilots, the NASA workforce, and high-value equipment and property. Systems have relied on high reliability components to provide the necessary safety margins and avoid operational mission failures. The current vision for future manned and unmanned space missions to the International Space Station, the Moon, Mars, and beyond, will require longer duration missions and will rely on complex assemblages of components. Increased mission duration and complexity increase the probability of operational mission failures that must be mitigated without jeopardizing safety or the objectives of the current or future missions that might reuse critical mission components. ISHM technology will be essential for providing near-real-time assessments of system capability, safety margins, and maintenance and sustainment requirements. The Applied Research Lab has conducted a series of workshops for NASA which focused on defining requirements for integrated system health monitoring and for the integration of health monitoring and control to provide intelligent self situational awareness (ISSA). The results of these workshops indicate that the benefits of ISHM and greater integration between ISHM and control include increased safety and mission assurance, the ability to rapidly respond to system failures, and decreased operator workload. Emerging open system standards such as OSA-EAI provide a framework for integrating system health monitoring with control functionality in spacecraft avionics systems. The purpose of this paper is to describe areas where system health monitoring can impact safety, reliability and sustainment in space applications and present the results of workshops conducted for NASA to identify requirements for the integration of health monitoring and control in future space systems

<div class="htmlview paragraph">NASA's Constellation Program, which includes the mission objectives of establishing a permanently-manned lunar Outpost, and the exploration of Mars, poses new and unique challenges for human life support systems that will require solutions beyond the Shuttle and International Space Station state of the art systems. In particular, the requirement to support crews for extended durations at the lunar outpost with limited resource resupply capability will require closed-loop regenerative life support systems with minimal expendables. Planetary environmental conditions such as lunar dust and extreme temperatures, as well as the capability to support frequent and extended-duration Extra-vehicular Activity's (EVA's) will be particularly challenging. This paper will discuss the NASA Constellation Program missions, phases, and major elements, and will discuss the state of the art technologies used in prior programs such as Apollo, Skylab, Space Shuttle, and International Space Station as a point of reference. New Constellation requirements driving technologies over prior programs and architectures will be discussed, including (but not limited to) lunar “anywhere access”, the construction of a permanently-crewed lunar outpost, growth in lunar crew size over Apollo, EVA requirements, challenges of lunar dust, and significant vehicle weight challenges. Although the Constellation requirements for the lunar mission phase and beyond are still under development by NASA, they will push the technology beyond the current state of the art. These life support technology development needs resulting from new mission requirements and architecture constraints will be addressed and prioritized.</div>

It is proposed that a fast-fission, heatpipe-cooled, lunar-surface power reactor system be divided into subcritical units that could be launched safely without the incorporation of additional spectral shift absorbers or other complex means of control. The reactor subunits are to be emplaced directly into the lunar regolith, utilizing the regolith not just for shielding but also as the reflector material to increase the neutron economy of the system. While a single subunit cannot achieve criticality by itself, coordinated placement of additional subunits will provide a critical reactor system for lunar surface power generation. A lunar regolith clustered-reactor system promotes reliability, safety, and ease of manufacture and testing at the cost of a slight increase in launch mass per rated power level and an overall reduction in neutron economy when compared to a single-reactor system. Additional subunits may be launched with future missions to increase the cluster size and power according to desired lunar-base power demand and lifetime. The results address the potential uncertainties associated with the lunar regolith material and emplacement of the subunit systems. Physical distance between subunits within the clustered emplacement exhibits the most significant feedback regarding changes in overall system reactivity. Narrow, deep holes will be the most effective in reducing axial neutron leakage from the core. The variation in iron concentration in the lunar regolith can directly influence the overall system reactivity, although its effects are less than the more dominant factors of subunit emplacement.