Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 – 23 September 2022
Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 September – 23 September 2022
TP3
Forward to the Moon: The Science of Exploration

TP3

Human and robotic lunar exploration is opening new vistas and scientific understanding as humanity reaches toward the Moon again. In partnership with institutions around the globe, the Solar System Exploration Research Virtual Institute (SSERVI) focuses on these scientific aspects of exploration as they relate to the Moon and other airless bodies. This session will feature interdisciplinary, exploration-related science centered around the Moon as a human and robotic destination. Scientific plans and results within this session represent the broad spectrum of lunar science representing investigations of the Moon and its environment as a planetary body as well as science research uniquely enabled by being done from the Moon. Graduate students and early career researchers are particularly encouraged to submit for oral presentations.

Co-organized by MITM
Convener: Gregory Schmidt | Co-conveners: Mahesh Anand, Kristina Gibbs, Brian Day
Orals
| Wed, 21 Sep, 12:00–13:30 (CEST), 15:30–18:30 (CEST)|Room Manuel de Falla
Posters
| Attendance Mon, 19 Sep, 18:45–20:15 (CEST) | Display Mon, 19 Sep, 08:30–Wed, 21 Sep, 11:00|Poster area Level 1

Session assets

Discussion on Slack

Orals: Wed, 21 Sep | Room Manuel de Falla

Chairpersons: Kristina Gibbs, Gregory Schmidt, Brian Day
12:00–12:10
|
EPSC2022-97
|
ECP
Shreekumari Patel, Animireddi V Satyakumar, and Mohamed Ramy El-maarry

Introduction: Floor-Fractured Craters (FFCs) are unique lunar landforms that have witnessed and recorded tectonic and volcanic activity in the form of distinct structural features [1]. FFCs are common around the edges of mare basins, and their ages span the lunar history [2,3]. They offer insights into the region’s magmatic, thermal and morphological evolution and are candidates for further investigation to comprehend the Moon’s crustal evolution. Therefore, the detailed analysis of FFCs would give new insights into a better understanding of the volcanic activity on the Moon. In connection with this, we selected a Posidonius crater on the nearside of the Moon to perform detailed geological and geophysical analysis to understand the volcanic history.

The Posidonius crater is ~95 km in diameter and is categorised as a Class-III Floor-Fractured crater located on the northeastern rim of the Serenitatis basin [4], with a center latitude and longitude of  31.88°N and 29.99°E as shown in Figure 1. The wide annular depression called moat is noted on the western side of the crater nearest to the exterior Mare Serenitatis plain. The mare infill is divided into two basaltic units by ~180 km long, curvy lava channel known as Rimae Posidonius. The existence of large and small-scale graben and sinuous rille and basaltic infill indicate that tectonic, as well as volcanic processes, deformed the Posidonius crater.

Data and Methodology: The gravity data from Gravity Recovery and Interior Laboratory (GRAIL) of degree and order 660 was used to map the gravity anomalies. The global lunar crustal thickness model-1 was used to see the crustal thickness variations. The composition of the crater and eastern part of Mare Serenitatis was derived using Moon Mineralogy Mapper (M3) onboard the Chandrayaan-1 mission [5]. Band parameters were calculated for mapping first-order mineralogical variation [6]. LRO (Lunar Reconnaissance Orbiter) Mini-RF S-band data was processed to derive CPR and daughter products [7] for the physical characterisation of the study region [8]. LRO NAC (Narrow-Angle Camera) of spatial resolution ~0.5-2 meters/pixel [9] was used to identify and map the structural features.

 

Results and Discussion:

The gravity anomalies ranged from -413 to 558 mGal (Figure 2A), with high values observed at the outer rim of the Serenitatis basin and low values found at the east, south-east of the Posidonius crater. These anomalies show the decreasing trend towards the northern part of Posidonius crater, indicating that the possible source of volcanic history is the Serenitatis basin. The crustal thickness (Figure 2B) shows low at Serenitatis and Posidonius crater, which suggests the volcanic source is shallow level. Minerals were identified using VNIR spectral characteristics. The crater exhibits exposures of mafic minerals detected from Rimae Posidonius, Floor-Fractures, central peak ring, and mare unit (Figure 3A). Pyroxene spectral shows absorption near 1000 nm and 2000 nm due to Fe2+ and Ca2+ contribution [10]. M3 data suggests that the mare unit is dominated by the subcalcic ferroaugite to Ferroaugite rich rocks such as basalt (Figure 3B and 3C). Spectra of bedrock exposures from rimae and ridge show the presence of magnesium-pigeonite, which suggests the rapid cooling of magma at high temperature. Hence, the enigmatic rimae Posidonius represent the shallow lava flow resulting from a turbulent flow of low-viscosity, high-temperature, rapid cooling lava that erodes the pre-existing mare deposits in Posidonius crater.

Mini-RF Circular Ratio Polarisation (CPR) and m-chi decomposition map of crater display the radar-bright characteristics of tectonic features and small-sized fresh craters. The Posidonius crater exhibits low-CPR values suggesting the maturity scale of the crater. Still, the central peak ring, rimae Posidonius, floor fracture, and small-sized fresh crater show high CPR values due to boulder fields in the vicinity. High-CPR value region represents the mixed scattering of double bounce and volumetric scattering (yellowish hue) as they expose fresh and/or dihedral geometrical surface concentrated at the base or in the vicinity of peak ring, linear/sinuous features, and secondary craters (Figure 4).

Conclusions:

The geological (M3, Mini-RF, and NAC analysis) and geophysical (gravity, crustal thickness) observations in this area revealed extensive eruptions during formation and after formation. It is also observed that the lithospheric loading of the Serenitatis basin influences the origin and modifications of this crater. The detailed analysis and mapping of this region are under process.

 

Acknowledgements

SP and MRELM acknowledge support for this work through an internal grant (8474000336-KU-SPSC). AVSK is thankful to the director, CSIR-NGRI, Hyderabad, for all the support.

References:

[1] Chauhan, M. et al. (2021) Lunar and Planetary Science Conference (LPSC) 2548, 1843.

[2] Jozwiak, L. M. et al. (2012) JGR:Planets 117(E11).

[3] Jozwiak, L. M. et al. (2015) Icarus 248, 424-227.

[4] Salem, I. B. et al. (2022) Remote Sensing 14(4), 814.

[5] Pieters, C. M. et al. (2009) Current Science, 500-505.

[6] Purohit, A. N. et al. (2021) Journal of Earth System Science 130(1), 1-23.

[7] Raney, R. K. et al. (2012) JGR: Planets 117(E00H21), 1-8.

[8] Patel, S. M. and Solanki, P. M. (2018) Proceedings ACRS, TS70.

[9] Robinson, M. S. et al. (2010) Space Science reviews 150, 81-124.

[10] Klima, R. L. et al. (2011) Meteorite and Planetary Science 46, 379-395.

How to cite: Patel, S., Satyakumar, A. V., and El-maarry, M. R.: Extensive volcanic activity within the Posidonius crater, nearside of the Moon, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-97, https://doi.org/10.5194/epsc2022-97, 2022.

12:10–12:20
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EPSC2022-280
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ECP
Hannes Bernhardt, Jaclyn D. Clark, and Mark. S. Robinson

Introduction: The Aristarchus Plateau is a unique region on the Moon, hosting its highest concentration of rilles including the widest and deepest rille [1], its most extensive dark mantle deposits [2], as well as rare exposures of both, very olivine-rich and very silicate-rich materials [3–6]. As such, the plateau has been considered as one of the most promising exploration sites apart from the lunar poles for decades [7–10]. To facilitate future in-situ operations and devise traverse plans on the plateau, we are mapping a 285 km2 area centered at 50.53°E 24.51°N, which includes crater Herodotus G, ~27 km northwest of the rim of crater Herodotus (Fig. 1, black outline). For context, and as there exists no dedicated, peer-reviewed map of the Aristarchus Plateau, we are producing a regional map (~103 km2) centered at 50.75°E 26.11°N, encompassing the entire plateau and the Montes Agricola. Here we present a progress report on this regional map (Fig. 1).

Data: A 7 m/pixel mosaic of SELENE (“Kaguya”) Terrain Camera (TC) morning images, i.e., with homogeneous illumination from the east [11] serves as our map base. We also utilize several other datasets (for explanation of abbreviations see references): LOLA-Kaguya (merged topography and derivatives [12]); LROC-WAC (high and low incidence [13]), Clementine (NIR and UV-VIS mosaics [14]); Diviner (rock abundance, CF position, and temperature [15]); Arecibo-Green Bank radar (S-band circular polarization, [16]). Pre-Kaguya/LRO maps including the Aristarchus plateau are also consulted for reference and regional context [17–19].

For our local mapping (Fig. 1, black rectangle), we will also consult three LROC-NAC mosaics (two opposing high incidence and one low incidence [13]) as well as NAC-derived stereo topography [20,21].

Methodology: Regional mapping is carried out at a scale of 1:80,000. Initial identification and digitization of linework and units is conducted on our basemap (Kaguya TC) in conjunction with merged LOLA-Kaguya data (topography, hillshade, and slopemap). Further unit characterization and delimitation is based on all datasets listed in the Data section.

Our regional mapping approach is similar to the composite map by [18]. However, we will map mineralogic units that lack corresponding morphologic or albedo signatures (e.g., olivine-rich areas on the southeastern rim of Aristarchus [3,4] or silicic areas in several specific locations [5,6]) as overlay textures instead of assigning separate units. For our local map we plan a mapping scale of 1:15,000 using LROC-NAC mosaics at different incidence angles as basemaps.

Initial results: We identified 45 potential volcanic collapse structures (irregular pits; IRPs; Fig. 1, red units) ranging in areal extent from ~0.3 km2 to ~110 km2 with a mean at ~7 km2. Most of these structures have not been reported in previous investigations and all but six IRPs are located on the Aristarchus plateau. IRPs were defined as depressions fulfilling at least three of the following criteria: 1) Irregular shape; 2) Anomalous depth-diameter-ratio; 3) Not surrounded by spectral signatures consistent with impact ejecta; 4) Connected to or closely associated with a rille or with a partially breached rim.

In our map, the term “rille” is defined as linear depression indicating a formation by volcanic drainage, i.e., it has to fulfill two of the following criteria: 1) Sinuous trace; 2) Following the topographic gradient; 3) Connected to or closely associated with an IRP. We mapped a total of 100 rilles with total, maximum, and minimum lengths of 1724 km, 110 km, and 0.5 km, respectively. Additionally, we identified 78 highly degraded rilles and segments, for a total rille length of ~2033 km. This includes at least 37 rilles and rille segments that have not been identified in previous investigations [1,18]. We also detected two ~3.7 km long and up to ~24 m high, sinuous ridge segments approaching Rima Krieger. Two more ~2.5 km and ~5 km long sinuous ridges are located north of the Montes Agricola. If these represent inverted rilles, they would triple the number of such features identified on the Moon [1].

Figure 1: Current state of our regional geomorphologic map of the Aristarchus Plateau (mapping scale 1:80,000); background is the merged LOLA-Kaguya Lunar Digital Elevation Model (LDEM). While preliminary linework is complete, mapping of units has just commenced. The black rectangle south of the image center outlines the area of our local mapping (scale 1:15,000) for potential landing site assessment.

References: [1] D.M. Hurwitz et al., PSS 79–80 (2013) 1–38. [2] L.R. Gaddis et al., Icarus 161 (2003) 262–280. [3] S. Le Mouélic et al., GRL 26 (1999) 1195–1198. [4] J.A. Arnold et al., JGR-P 121 (2016) 1342–1361. [5] P.G. Lucey et al., JGR 91 (1986) 344–354. [6] J.F. Mustard et al., JGR 116 (2011) E00G12. [7] R. O’Connell, A. Cook, NASA Authorization for Fiscal Year 1970, 1969. [8] C.R. Coombs et al., in: Sp. 98, Reston, VA, 1998, pp. 608–615. [9] E. Jawin et al. (2021) Bull. Am. Astron. Soc., 53, . [10] T.D. Glotch et al., Planet. Sci. J. 2 (2021) 136. [11] J. Haruyama et al., Earth, Planets Sp. 60 (2008) 243–255. [12] M.K. Barker et al., Icarus 273 (2016) 346–355. [13] M.S. Robinson et al., SSR 150 (2010) 81–124. [14] A.S. McEwen, M.S. Robinson, Adv. Sp. Res. 19 (1997) 1523–1533. [15] J.L. Bandfield et al., JGR 116 (2011) E00H02. [16] B.A. Campbell et al., Icarus 208 (2010) 565–573. [17] H.J. Moore, USGS I-Map 465, 1965. [18] T.A. Lough et al. (2011) LPS XLII, abstract #2013. [19] H.J. Moore, USGS I-Map 527, 1967. [20] Z.M. Moratto et al. (2014) LPS XLV, abstract #2892. [21] M.R. Henriksen et al. (2015) Second Planet. Data Work., pp. 2–3.

How to cite: Bernhardt, H., Clark, J. D., and Robinson, M. S.: Regional and Local Geomorphologic Mapping of the Aristarchus Plateau, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-280, https://doi.org/10.5194/epsc2022-280, 2022.

12:20–12:30
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EPSC2022-272
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ECP
Lunar Silicic Magma Genesis: Insights from Rhyolite-MELTS Modeling
(withdrawn)
Srinidhi Ravi, Christy Till, and Mark Robinson
12:30–12:40
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EPSC2022-295
Daniel Moriarty and Noah Petro

Within the next decade, humans are slated to return to the Moon via NASA’s Artemis Program.  A driving goal of this program is to establish a sustained presence at one or more sites near the lunar south pole.  Artemis astronauts are expected to participate in a diverse suite of scientific investigations, many of which leverage the extreme illumination and thermal environment at the lunar poles [1].

The lunar south pole is also relevant to geological investigations providing new insight into fundamental planetary processes.  Specifically, Goal 1b of the Artemis III Science Definition Team Report [1] is to probe planetary differentiation and evolution processes including formation of a magma ocean, crust, mantle, and core.

The Artemis program will address this goal in several ways.  The lunar south pole is set within highlands crustal terrane far-removed from previous lunar sample return missions (e.g., the Apollo and Luna programs).  Sampling local crustal material will provide important insight into ancient crust-building processes (i.e., differentiation of the lunar magma ocean). 

Ejecta from nearby impact basins will provide further insight into a wider range of planetary processes.  Specifically, the lunar south pole is in the vicinity of the ~2000 km South Pole – Aitken Basin (SPA), the oldest and largest impact structure preserved on the Moon. Due to its size, age, and unique geophysical properties, SPA impact melt and ejecta samples are critical to unraveling lunar differentiation, the interior structure of the lower crust and upper mantle, and lunar chronology. Unusual volcanic resurfacing across SPA reveal complexities in the Moon’s thermal evolution [2]–[4]

SPA ejecta is associated with pronounced geochemical and mineralogical signatures, including Th, Fe, Ti, KREEP, and high-Ca pyroxene elevated relative to the surrounding highlands [5].  These compositional properties are consistent with exposure of late-stage lunar magma ocean cumulates[6]. 

These ancient mantle materials excavated by SPA are concentrated in the NW quadrant of the basin, presumably downrange from the impact[5], [7].  However, the relevant compositional signatures are also observed across the southern region of the basin, encompassing the lunar south pole (Figures 1+2).  Using these compositional properties as a guide, Artemis astronauts will be able to identify and return candidate lunar mantle materials for detailed analyses in terrestrial laboratories.

Figure 1:  The expected distribution of mantle materials ejected by SPA and modified by subsequent impact events (right) closely matches the distribution of thorium, a possible marker of late-stage lunar magma ocean cumulates (left) [5].  Small elevations in thorium persist across the south polar region.

Figure 2:  1 micron Integrated Band Depth maps constructed from Moon Mineralogy Mapper data reveal an elevated pyroxene abundance across the south polar region associated with SPA [8]. 

While fragments of SPA material are likely to be sampled at the Artemis site(s), the most recent planetary science decadal survey [9] strongly recommends a more direct approach to maximize the sample return of the Artemis program.  Endurance-A [10], a mission concept study performed at the Jet Propulsion Laboratory and released with the Decadal survey, is a long-range robotic rover that would collect samples from multiple points of interest along a traverse beginning in central SPA and ending at a rendezvous with Artemis astronauts (Figure 3). As currently planned, the rover would collect and deliver up to ~100 kg of samples from ~12 sites, providing a diverse overview of the basin addressing numerous high-priority lunar science questions relevant to solar system chronology and lunar evolution.  The rover is outfitted with a suite of instruments providing sampling context and in situ science measurements.

Figure 3:  An example traverse for Endurance-A (purple) beginning in at Mons Marguerite (an unusual volcanic construct) and sampling SPA impact melt (SW Bhabha, Bose), mare basalts (Haret C mare), high-Th mantle ejecta (Abbe M), subsequent impact melt (Poincare, Schrodinger peak ring, Lyman), and pyroclastic materials (Schrodinger pyroclastics) en route to the Artemis base camp [10]. 

[1]         Weber et al., in Lunar and Planetary Science Conference, 2021, no. 2548.

[2]         James and Kiefer, in AGU Fall Meeting Abstracts, 2017, vol. 2017.

[3]         Moriarty and Pieters, (2015), Geophys. Res. Lett., vol. 42, no. 19,

[4]         Moriarty and Pieters, (2018), J. Geophys. Res. Planets, vol. 123, no. 3,

[5]         Moriarty et al., (2021), J. Geophys. Res. Planets, vol. 126, no. 1,

[6]         Moriarty et al., (2021), Nat. Commun., vol. 12, no. 1,

[7]         Melosh et al., (2017), Geology, vol. 45, no. 12,

[8]         Moriarty and Petro, in Lunar and Planetary Science Conference, Mar. 2020.

[9]         National Academies of Sciences et al., (2022).

[10] Keane et al., (2022).

 

How to cite: Moriarty, D. and Petro, N.: Insights into Lunar Differentiation, Evolution, and Chronology from the Artemis Program, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-295, https://doi.org/10.5194/epsc2022-295, 2022.

12:40–12:50
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EPSC2022-646
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ECP
Irene Bernt, Ana-Catalina Plesa, Sabrina Schwinger, Max Collinet, and Doris Breuer

Introduction

The early Moon was covered by a global lunar magma ocean (LMO) whose solidification set the initial stage for the subsequent thermochemical evolution. Equilibrium solidification leads to a homogeneous initial mantle composition, while fractional solidification leads to a layered heterogeneous mantle composition. This difference is crucial for the subsequent thermochemical evolution of the lunar mantle and the amount of secondary crust produced. Estimates of the thickness of the secondary crust, which consists of Mg-suite rocks and basaltic lava flows, and the composition of these rocks from surface measurements and Apollo samples can be combined with models of the interior dynamics to gain insight into the evolution of the lunar mantle. 

In our study we model the solid state convection in the lunar mantle and focus on the mixing and partial melt production during convection. We consider both a homogeneous initial mantle composition, as it was used in previous studies (e.g., Ziethe et al., 2009), and a heterogeneous mantle composition that formed by fractional crystallization of the LMO.

We compute the amount of partial melt and compare our results to estimates of the Moon’s secondary crust. This allows us to constrain parameters such as the initial temperature for the homogeneous case and the temperature dependence of the viscosity for the heterogeneous case. Our models can provide critical information about the location and timing of partial melt, and for the more realistic heterogeneous case, also about the components that undergo melting.

Petrological modeling

For the initial mantle composition in the homogeneous lunar mantle case we chose KLB-1 peridotite (Zhang and Herzberg, 1994). The solidus, liquidus and density change due to mantle depletion were calculated with alphaMELTS. The initial temperature profiles vary from a cold to an intermediate temperature following Laneuville et al. (2013) (Figure 1b). 

For the heterogeneous lunar mantle case we follow the approach described by Schwinger and Breuer (2021) to compute the fractional solidification of the LMO using the bulk lunar mantle composition of O‘Neil (1991). The resulting compositional structure of the mantle consists of 5 layers, for which the predominant minerals are shown in Figure 1c. For each of these layers we calculate an average density, solidus and liquidus profiles, and their changes due to mantle depletion. The initial temperature profile follows the crystallization temperatures of the cumulates (Figure 1d). 

Geodynamical modeling

We use the mantle convection code GAIA (Hüttig et al., 2013) to model the thermochemical evolution of the lunar mantle for both the homogeneous and heterogeneous case. We solve the conservation equations of mass, linear momentum, thermal energy, and composition using the extended Boussinesq Approximation in a 2D quarter cylinder geometry. The temperature- and depth-dependent viscosity follows an Arrhenius law, and we track material properties (e.g., melting temperature, density, degree of depletion, amount of heat producing elements) employing a particle-in-cell method (Plesa et al., 2013).

All simulations consider core cooling and radioactive decay. Additionally, we account for latent heat consumption during mantle melting and the increase of solidus and density changes due to mantle depletion (Breuer et al., 2018). Our models track the timing and depth of the melting events and the components that melt.

Produced melt forms the secondary crust and successful models must fit the secondary crust thickness with values between 2 to 10 km. This range accounts for basaltic lava flows that comprise less than 1% of today's crust (Head, 1976) and the Mg-suite rocks that may comprise 6% to 30% (Tompkins and Pieters, 1998, Wieczorek and Zuber, 2001). Though, recent findings show that at least some rocks of the Mg-suite are impact melts (White et al., 2020).

Results

For the homogeneous case, our models show that a relatively cold initial potential mantle temperature of 1501 - 1547 K is required to match the secondary crust estimates of 2 to 10 km. The cold temperatures correspond to abnormally small initial magma ocean depths of only 106 - 145 km and are not able to produce early mantle melting as required to explain the oldest ages of basalts (Figure 2a).

For the heterogeneous case the initial temperature profile is determined by the crystallization temperatures and is thus a fixed parameter. In this case, the IBC cumulates with their high density and low solidus temperature can significantly affect convection and subsequent partial melting. We consider a reference viscosity of 1e21 Pa s. For models with a strong temperature-dependence of the viscosity (i.e., activation energy of 300 kJ/mol) the IBC remains trapped beneath the crust, and only 1.3 km of secondary crust are produced. In contrast, if we consider a lower temperature-dependence of the viscosity (i.e., activation energy of 83 kJ/mol), then up to 61% of IBC sinks into the mantle, producing  an average secondary crust thickness of up to 2.9 km (Figure 2b).

Conclusion and Outlook 

Our coupled petrological-geodynamical models indicate that a heterogeneous mantle composition yields more comparable results to estimates of the secondary crustal thickness than a homogeneous mantle. In the heterogeneous case, at least part of the IBC layer needs to be recycled into the mantle to match the estimates, indicating a low activation energy e of the viscosity, a low reference viscosity or additional mechanisms to destabilize the IBC layer. In the homogeneous case, our models show that only cold initial temperatures can produce a secondary crust thickness comparable to the estimates - but these are not consistent with the timing of secondary crust formation.

In future work, we will investigate the composition of the partial melt over time using the thermodynamic software Perple_X and compare our results to the composition of mare basalts. In addition, we plan to test the consequences of a heterogeneous shallow magma ocean on the thermochemical evolution and mantle melt production. 

Future missions that could return additional information about the thickness and composition of the secondary crust would greatly help to improve our numerical models and constrain the thermochemical history of the Moon.

Acknowledgements

I.B. and S.S. were supported by DFG SFB-TRR170, (subprojects C4 and A5).

How to cite: Bernt, I., Plesa, A.-C., Schwinger, S., Collinet, M., and Breuer, D.: Homogeneous versus heterogeneous lunar mantle: Constraints from secondary crust production, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-646, https://doi.org/10.5194/epsc2022-646, 2022.

12:50–13:00
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EPSC2022-346
Akos Kereszturi, Sarah Boazman, David Heather, Richard Tomka, and Tristam Warren

The evaluation of candidate landing sites for a solar powered ice drilling mission for the Moon was done at the southern polar region. Selection criteria were low slope angle surface, occasionally solar illuminated location with direct Earth radio access, together with <125 K temperature at 1 m depth. The survey showed thee-four areas where all of these needs were satisfied at sites close to each other (see the Figuew 1 below). Considering these regions, the maximal diameter for safe and scientifically relevant landing ellipse sizes are around 0.5-1 km diameter, while containing <20% of unfavourable locations can be larger around 2-4 km. The best location is around -27.03 W -86.75 S, where solar illumination can have 30% of time at least and WEH values are elevated. 

 

Figure 1. Insets of magnified versions of the four candidate areas.

How to cite: Kereszturi, A., Boazman, S., Heather, D., Tomka, R., and Warren, T.: Four candidate landing sites at the southern lunar polar region to drill water ice using solar powered missions, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-346, https://doi.org/10.5194/epsc2022-346, 2022.

13:00–13:10
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EPSC2022-530
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ECP
|
MI
Sarah Boazman, Akos Kereszturi, David Heather, Elliot Sefton-Nash, Csilla Orgel, Richard Tomka, Berengere Houdou, and Xavier Lefort

The south polar region is an area of renewed interest of lunar exploration because of the presence of volatiles including water ice at the surface or just beneath the surface (e.g., Deutsch et al., 2020, Hayne et al.,2015, Kring et al., 2020, Lemelin et al., 2021, Lemelin 2020, Li et al., 2018). PROSPECT is an instrument selected for flight on the 10th NASA Commercial Lunar Payload Services (CLPS) mission and aims to sample the lunar surface up to 1 m depth. Samples will be analysed for volatiles, and the gases given off when the samples are heated will be analysed by an onboard laboratory containing two spectrometers. PROSPECT will develop our understanding of the abundance and origin of volatiles in the south polar region and will also perform In-Situ Resource Utilisation experiments, extracting oxygen from lunar minerals (Heather et al., 2022). NASA CLPS-10 will be a static lander, so for PROSPECT to be able to sample the most volatile rich lunar soils, it is essential to select the correct landing site, with conditions most suited to the presence of volatiles while meeting all necessary engineering constraints.

Methods and Datasets:

We have used a combination of datasets with GIS remote sensing methods to investigate the south polar region (75°-90° S), including Lunar Reconnaissance Orbiter (LRO) images; NAC (Narrow Angle Camera) and WAC (Wide angle camera) (Robinson et al., 2010). We have analysed the elevation of the region using the LOLA 30 m/pixel dataset. Slope maps were created and classified into less than 10° and less than 5° to analyse the areas that are the most accessible. The surface temperatures of the region have also been analysed using both seasonal data from Diviner and data from the Oxford Thermal Model (King et al., 2020, Kereszturi et al., 2022). M3 ice exposures of the region have been identified and compared with surface temperatures and the slopes within the region (Li et al., 2018). The Mazarico et al., 2011 illumination model was also used alongside a toolkit from iSPACE (Luxembourg) to investigate the Earth visibility, horizon, and surface illumination (ispace (ispace-inc.com).  Additionally hazards to landing such as craters and boulders have been identified within the region.

Results:

The south polar region shows large variations in elevation and slopes present due to the highly cratered surface and additionally the topography shows elevated areas and large ridges. However, there are large areas that have slopes less than 10°, which would be suitable for landing a mission that carries PROSPECT or for a future EVA (Figure1).

Temperature analysis from seasonal Diviner data shows that there are areas within the region that reach temperatures less than 100 K during the summer and winter and would allow for water ice to be stable if present. There are large areas that have temperatures less than 100 K that also have slopes less than 10° and therefore would be potentially a safe area to land and sample. The M3 ice exposures support the seasonal Diviner temperature data findings and there are areas where the slopes are less than 5° that correlate with the surface temperatures less than 100 K and with ice exposures shown by M3. (Figures 1c and d).

Future work:

This initial investigation into volatiles within the south polar region has highlighted some areas where there is evidence to suggest water ice may be present in areas where there are slopes less than 10°. These areas will be further investigated to study their accessibility, illumination conditions and Earth visibility. Additionally, other datasets such as KAGUYA will be used to understand the mineralogy of these regions of interest. These regions of interest will be analysed further by mapping potential hazards such as craters, boulders, and rock falls to assess the accessibility of these areas, for PROSPECT and for future missions.

 

Acknowledgement: This work was supported by the H82 POLICETECH project.

 

References:

Deutsch, A., et al., (2020) Icarus, 336.

Hayne, P., et al., (2015) Icarus, 255, 58-69

Heather, D.J. et al., (2022) EPSC, This meeting

Kring, D., et al., (2020) LPSC, 51st

Kereszturi, A., et al., (2022) EPSC, This meeting

Lemelin, M., et al., (2021) Planetary Science Journal, 2(3).

Lemelin, M., et al., (2020) LPSC 51st

Li, S., et al., (2018) Earth, atmospheric and planetary sciences, 115(36)

Mazarico,E., et al., (2011) Icarus,1066-1081,211(2)

Robinson, M., et al., (2010) Space Science Reviews, 81-124,150(1-4)