Lunar Prospecting Using Thermal Wadis and Compact Rovers

Recent missions have confirmed the existence of water and other volatiles on the Moon, both in permanently-shadowed craters and elsewhere. Non-volatile lunar resources may represent significant additional value as infrastructure or manufacturing feedstock. Characterization of lunar resources in terms of abundance concentrations, distribution, and recoverability is limited to in-situ Apollo samples and the expanding remote-sensing database. This paper introduces an approach to lunar resource prospecting supported by a simple lunar surface infrastructure based on the Thermal Wadi concept of thermal energy storage and using compact rovers equipped with appropriate prospecting sensors and demonstration resource extraction capabilities. Thermal Wadis are engineered sources of heat and power based on the storage and retrieval of solar-thermal energy in modified lunar regolith. Because Thermal Wadis keep compact prospecting rovers warm during periods of lunar darkness, the rovers are able to survive months to years on the lunar surface rather than just weeks without being required to carry the burdensome capability to do so. The resulting lower-cost, long-lived rovers represent a potential paradigm breakthrough in extra-terrestrial prospecting productivity and will enable the production of detailed resource maps. Integrating resource processing and other technology demonstrations that are based on the content of the resource maps will inform engineering economic studies that can define the true resource potential of the Moon. Once this resource potential is understood quantitatively, humans might return to the Moon with an economically sound objective including where to go, what to do upon arrival, and what to bring along

Considering Homophily’s Role in the Development of Successful Extension Programs in International Settings: Volunteer Effectiveness and Farmer Perceptions in Guatemala and Dominican Republic

Research on the educator-learner homophily effect in influencing educator credibility, learner attitudes, knowledge retention, and behavior change remains limited and inconclusive. This study investigated how educator-learner homophily influences small-scale farmers’ willingness to adopt agricultural technologies. Using a multi-case study approach, focus groups and key informant interviews were conducted with 60 small-scale farmers in Guatemala and the Dominican Republic who received agricultural training from U.S. volunteers. Farmers’ perceptions of learning and educator credibility were analyzed. Guided by the Moscarelli Model (2023), which theorizes that perceived educator credibility comprises subject matter expertise and trustworthiness—moderated by educator-learner homophily—findings revealed an unexpected dynamic. Farmers rated U.S. volunteers as more credible and reliable than local extension agents, despite lower sociodemographic homophily between the farmers and U.S. volunteers. These findings challenge traditional assumptions about the role of homophily in international extension systems. By illuminating how educator-learner homophily influences knowledge transfer and behavior change, this study offers insights for designing more effective extension programs. Volunteer program funders, administrators, and educators can leverage these insights to enhance program outcomes. This research advances the understanding of homophily’s role in educator credibility and learner outcomes, calling for a reevaluation of its traditional conceptualization in international education contexts. It supports the conceptualization that homophily may shape the effectiveness of knowledge transfer and behavior change, particularly within programs relying on international volunteers

Thermal Wadis in Support of Lunar Exploration: Concept Development and Utilization

Thermal wadis, engineered sources of heat, can be used to extend the life of lunar rovers by keeping them warm during the extreme cold of the lunar night. Thermal wadis can be manufactured by sintering or melting lunar regolith into a solid mass with more than two orders of magnitude higher thermal diffusivities compared to native regolith dust. Small simulant samples were sintered and melted in the electrical furnaces at different temperatures, different heating and cooling rates, various soaking times, under air, or in an argon atmosphere. The samples were analyzed with scanning electron microscopy and energy dispersive spectroscopy, X-ray diffraction, a laser-flash thermal diffusivity system, and the millimeter-wave system. The melting temperature of JSC-1AF simulant was ~50°C lower in an Ar atmosphere compared to an air atmosphere. The flow of Ar during sintering and melting resulted in a small mass loss of 0.04 to 0.1 wt% because of the volatization of alkali compounds. In contrast, the samples that were heat-treated under an air atmosphere gained from 0.012 to 0.31 wt% of the total weight. A significantly higher number of cavities were formed inside the samples melted under an argon atmosphere, possibly because of the evolution of oxygen bubbles from iron redox reactions. The calculated emissivity of JSCf-1AF simulant did not change much with temperature, varying between 0.8 and 0.95 at temperatures from 100 to 1200°C. The thermal diffusivities of raw regolith that was compressed under a pressure of 9 metric tons ranged from 0.0013 to 00011 in the 27 to 390°C temperature range. The thermal diffusivities of sintered and melted JSC-1AF simulant varied from 0.0028 to 0.0072 cm2/s with the maximum thermal diffusivities observed in the samples that were heated up 5°C/min from RT to 1150°C under Ar or air. These thermal diffusivities are high enough for the rovers to survive the extreme cold of the Moon at the rim of the Shackleton Crater and allow them to operate for months (or years) as opposed to weeks on the lunar surface. Future investigations will be focused on a system that can efficiently construct a thermal wadi from the lunar mare regolith. Solar heating, microwave heating, or electrical resistance melting are considered