arXiv subjects

Natalie M. Curran

Publications and source records attributed to Natalie M. Curran.

4 recordsLinked to original sources

arXiv2026

Potential survivable niches for microbial life on the lunar south pole

Most lunar surface conditions are incredibly harsh for microbial survival. High ultraviolet radiation, temperatures, and energetic particle radiation limit survival over most unprotected lunar surfaces, particularly in equatorial regions where all previous crewed exploration occurred. However, whether these harsh conditions are widespread at lunar poles has not been examined considering topographical effects. Here, we show that recent microorganism survivability data and lunar surface remote sensing reveal likely survivable niches in lunar polar regions. Analysis of topography and latitude-driven surface conditions using remote sensing data and high-resolution illumination models indicates the lunar south pole possesses significant regions with persistent low temperatures and ultraviolet flux. Comparing these conditions to survivability data of specific microorganisms, we find significant lunar polar areas likely possess surface conditions amenable to microbial survival. Our findings suggest lunar polar regions may be less hostile to microbial survival than previously assumed. This does not encompass growth likelihood, but survival in a cryptobiotic state where growth would be possible if habitable conditions were present. Potential microbial survivability at lunar poles is particularly significant given many examined microbes will likely be transported to the Moon during crewed lunar south pole exploration planned in numerous near-term missions. Thoughtfully planning exploration and tracking its impact is key to limiting and understanding potential unintended life transfer to the Moon.

astro-ph.EP↗

arXiv2023

In-situ Optimized Substrate Witness Plates: Ground Truth for Key Processes on the Moon and Other Planets

Future exploration efforts of the Moon, Mars and other bodies are poised to focus heavily on persistent and sustainable survey and research efforts, especially given the recent interest in a long-term sustainable human presence at the Moon. Key to these efforts is understanding a number of important processes on the lunar surface for both scientific and operational purposes. We discuss the potential value of in-situ artificial substrate witness plates, powerful tools that can supplement familiar remote sensing and sample acquisition techniques and provide a sustainable way of monitoring processes in key locations on planetary surfaces while maintaining a low environmental footprint. These tools, which we call Biscuits, can use customized materials as wide ranging as zircon-based spray coatings to metals potentially usable for surface structures, to target specific processes/questions as part of a small, passive witness plate that can be flexibly placed with respect to location and total time duration. We examine and discuss unique case studies to show how processes such as water presence/transport, presence and contamination of biologically relevant molecules, solar activity related effects, and other processes can be measured using Biscuits. Biscuits can yield key location sensitive, time integrated measurements on these processes to inform scientific understanding of the Moon and enable operational goals in lunar exploration. While we specifically demonstrate this on a simulated traverse and for selected examples, we stress all groups interested in planetary surfaces should consider these adaptable, low footprint and highly informative tools for future exploration.

astro-ph.EP↗

arXiv2021

In Situ Geochronology for the Next Decade: Mission Designs for the Moon, Mars, and Vesta

Geochronology, or determination of absolute ages for geologic events, underpins many inquiries into the formation and evolution of planets and our Solar System. Absolute ages of ancient and recent magmatic products provide strong constraints on the dynamics of magma oceans and crustal formation, as well as the longevity and evolution of interior heat engines and distinct mantle/crustal source regions. Absolute dating also relates habitability markers to the timescale of evolution of life on Earth. However, the number of geochronologically-significant terrains across the inner Solar System far exceeds our ability to conduct sample return from all of them. In preparation for the upcoming Decadal Survey, our team formulated a set of medium-class (New Frontiers) mission concepts to three different locations (the Moon, Mars, and Vesta) where sites that record Solar System bombardment, magmatism, and/or habitability are uniquely preserved and accessible. We developed a notional payload to directly date planetary surfaces, consisting of two instruments capable of measuring radiometric ages in situ, an imaging spectrometer, optical cameras to provide site geologic context and sample characterization, a trace element analyzer to augment sample contextualization, and a sample acquisition and handling system. Landers carrying this payload to the Moon, Mars, and Vesta would likely fit into the New Frontiers cost cap in our study (~$1B). A mission of this type would provide crucial constraints on planetary history while also enabling a broad suite of investigations such as basic geologic characterization, geomorphologic analysis, ground truth for remote sensing analyses, analyses of major, minor, trace, and volatile elements, atmospheric and other long-lived monitoring, organic molecule analyses, and soil and geotechnical properties.

astro-ph.EP↗

arXiv2019

Was the Sun a Slow Rotator? -- Sodium and Potassium Constraints from the Lunar Regolith

While the Earth and Moon are generally similar in composition, a notable difference between the two is the apparent depletion in moderately volatile elements in lunar samples. This is often attributed to the formation process of the Moon and demonstrates the importance of these elements as evolutionary tracers. Here we show that paleo space weather may have driven the loss of a significant portion of moderate volatiles, such as sodium and potassium from the surface of the Moon. The remaining sodium and potassium in the regolith is dependent on the primordial rotation state of the Sun. Notably, given the joint constraints shown in the observed degree of depletion of sodium and potassium in lunar samples and the evolution of activity of solar analogues over time, the Sun is highly likely to have been a slow rotator. Since the young Sun's activity was important in affecting the evolution of planetary surfaces, atmospheres, and habitability in the early Solar System, this is an important constraint on the solar activity environment at that time. Finally, since solar activity was strongest in the first billion years of the Solar System, when the Moon was most heavily bombarded by impactors, evolution of the Sun's activity may also be recorded in lunar crust and would be an important well-preserved and relatively accessible record of past Solar System processes.

astro-ph.EP↗