Advancing to Lunar Lava Tube Sensing : A New Radar Perspective of Philolaus Skylight Candidates (original) (raw)
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Detection of Intact Lava Tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder
Intact lunar lava tubes offer a pristine environment to conduct scientific examination of the Moon's composition and potentially serve as secure shelters for humans and instruments. We investigated the SELENE Lunar Radar Sounder (LRS) data at locations close to the Marius Hills Hole (MHH), a skylight potentially leading to an intact lava tube, and found a distinctive echo pattern exhibiting a precipitous decrease in echo power, subsequently followed by a large second echo peak that may be evidence for the existence of a lava tube. The search area was further expanded to 13.00–15.00°N, 301.85–304.01°E around the MHH, and similar LRS echo patterns were observed at several locations. Most of the locations are in regions of underground mass deficit suggested by GRAIL gravity data analysis. Some of the observed echo patterns are along rille A, where the MHH was discovered, or on the southwest underground extension of the rille.
2016
With the goal of expanding human presence beyond Earth, sub-surface empty lava tubes on other worlds form ideal candidates for creating a permanent habitation environment safe from cosmic radiation, micrometeorite impacts and temperature extremes. In a step towards Mars exploration, the Moon offers the most favorable pathway for lava tube exploration. In-depth analysis of GRAIL gravity data has revealed several candidate empty lava tubes within the lunar maria. The goal of this investigation is a proposed subsurface radar sounding mission to explore the regions of interest and potentially confirm the presence and size of buried empty lava tubes under the lunar surface.
Lunar Advanced Radar Orbiter for Subsurface Sounding (LAROSS): Lava Tube Exploration Mission
With the goal of expanding human presence beyond Earth, sub-surface empty lava tubes on other worlds form ideal candidates for creating a permanent habitation environment safe from cosmic radiation, microm-eteorite impacts and temperature extremes. In a step towards Mars exploration , the Moon offers the most favorable pathway for lava tube exploration. In-depth analysis of GRAIL gravity data has revealed several candidate empty lava tubes within the lunar maria. The goal of this investigation is a proposed subsurface radar sounding mission to explore the regions of interest and potentially confirm the presence and size of buried empty lava tubes under the lunar surface.
First look by the Yutu-2 rover at the deep subsurface structure at the lunar farside
Nature Communications
The unequal distribution of volcanic products between the Earth-facing lunar side and the farside is the result of a complex thermal history. To help unravel the dichotomy, for the first time a lunar landing mission (Chang’e-4, CE-4) has targeted the Moon’s farside landing on the floor of Von Kármán crater (VK) inside the South Pole-Aitken (SPA). We present the first deep subsurface stratigraphic structure based on data collected by the ground-penetrating radar (GPR) onboard the Yutu-2 rover during the initial nine months exploration phase. The radargram reveals several strata interfaces beneath the surveying path: buried ejecta is overlaid by at least four layers of distinct lava flows that probably occurred during the Imbrium Epoch, with thicknesses ranging from 12 m up to about 100 m, providing direct evidence of multiple lava-infilling events that occurred within the VK crater. The average loss tangent of mare basalts is estimated at 0.0040-0.0061.
Lunar and Martian Lava Tube Exploration as Part of an Overall Scientific Survey
2009
Andrew W. Daga, M.M. Battler, J.D. Burke, I.A. Crawford, R.J. Léveillé, S.B. Simon, L.T. Tan. 1 University of North Dakota and Andrew Daga & Associates, LLC, 111 Mountain Laurel Lane, Malvern, PA 19355, Centre for Planetary Science & Exploration, University of Western Ontario, 1151 Richmond Street, London, ON, Canada, N6A 3K7 mbattle@uwo.ca, The Planetary Society, 65 North Catalina, Avenue, Pasadena, CA 91106 jdburke@caltech.edu, Department of Earth and Planetary Sciences, Birkbeck College London, Malet Street, London, WC1E 7HX, i.crawford@ucl.ac.uk, Canadian Space Agency, 6767 route de l’Aéroport, Saint-Hubert, QC, Canada, J3Y 8Y9, richard.leveille@asccsa.gc.ca, Department of the Geophysical Sciences, The University of Chicago, sbs8@uchicago.edu, University College London Chadwick Building, Gower Street Lo don,WC1E 6BT, UK l.tan@ucl.ac.uk.
New insight into lunar impact melt mobility from the LRO camera
Geophysical Research Letters, 2010
1] The Lunar Reconnaissance Orbiter Camera (LROC) is systematically imaging impact melt deposits in and around lunar craters at meter and sub-meter scales. These images reveal that lunar impact melts, although morphologically similar to terrestrial lava flows of similar size, exhibit distinctive features (e.g., erosional channels). Although generated in a single rapid event, the post-impact mobility and morphology of lunar impact melts is surprisingly complex. We present evidence for multi-stage influx of impact melt into flow lobes and crater floor ponds. Our volume and cooling time estimates for the postemplacement melt movements noted in LROC images suggest that new flows can emerge from melt ponds an extended time period after the impact event. Citation: Bray, V. J., et al. , New insight into lunar impact melt mobility from the LRO camera, Geophys.
Geophysical evidence for melt in the deep lunar interior and implications for lunar evolution
Journal of Geophysical Research: Planets, 2014
Analysis of lunar laser ranging and seismic data has yielded evidence that has been interpreted to indicate a molten zone in the lowermost mantle overlying a fluid core. Such a zone provides strong constraints on models of lunar thermal evolution. Here we determine thermochemical and physical structure of the deep Moon by inverting lunar geophysical data (mean mass and moment of inertia, tidal Love number, and electromagnetic sounding data) in combination with phase-equilibrium computations. Specifically, we assess whether a molten layer is required by the geophysical data. The main conclusion drawn from this study is that a region with high dissipation located deep within the Moon is required to explain the geophysical data. This region is located within the mantle where the solidus is crossed at a depth of ∼1200 km (≥1600 • C). Inverted compositions for the partially molten layer (150-200 km thick) are enriched in FeO and TiO 2 relative to the surrounding mantle. The melt phase is neutrally buoyant at pressures of ∼4.5-4.6 GPa but contains less TiO 2 (<15 wt %) than the Ti-rich (∼16 wt %) melts that produced a set of high-density primitive lunar magmas (density of 3.4 g/cm 3 ). Melt densities computed here range from 3.25 to 3.45 g/cm 3 bracketing the density of lunar magmas with moderate-to-high TiO 2 contents. Our results are consistent with a model of lunar evolution in which the cumulate pile formed from crystallization of the magma ocean as it overturned, trapping heat-producing elements in the lower mantle.
Ballistically emplaced impact melt around the lunar crater Pierazzo 1 2
2018
13 Impact melt flows are observed to emerge from the continuous and discontinuous ejecta 14 blanket of the 9 km lunar crater Pierazzo, from the crater rim to more than 40 km away 15 from the center of the crater. Our mapping and modeling results suggest that melt can be 16 incorporated into ejecta and emplaced ballistically. It also confirms the idea that impact 17 melt can travel beyond the continuous ejecta blanket.. Our analysis is based on the 18 identification of established melt morphology for these in-ejecta flows, and their 19 occurrence on 6 to 18 slopes too shallow for dry granular flows beginning at rest. We 20 also compared the fractal dimension of the flow boundaries to established melt and granular 21 flows, providing more support for these flows being melt-rich instead of granular in origin. 22 Ejected melt flows are noted within just 1.5% of the mapping area, suggesting that 23 the surface expression of impact melt in the extended ejecta around craters of this size ...
Search for eternally sunlit areas at the lunar South Pole from recent data: new indications found
Recent lunar missions have revealed areas near the lunar South Pole that are lit for a very large fraction of time. These Peaks of Eternal Light (PEL) were found to be close to permanently shaded craters containing large quantities of water ice. The combination of these features makes the lunar South Pole a primary option for an early lunar base, a benign place, where the abundance of solar energy can convert the ice into valuable fuel for the trip back to Earth or further out into the solar system. However, one encounters practical problems when planning a mission to such an oasis in the cold: the PEL is still hypothetical, its location and size are not precisely known. As a consequence, the practical feasibility of a PEL pinpoint landing is not yet quantified. The objective of this paper is to pinpoint the Peak of Eternal Light (PEL) on the lunar South Pole and to understand its surroundings. Three techniques were developed by which conclusions can be drawn from relatively little photographic data: 1. The development of a Digital Elevation Map (DEM) from shadow simulation on wax clay, plus the S/W that can be used for assessment of lighting and communication conditions during orbital, landing and roving activities. 2. The use of Monthly Illumination Spectra (MIS) to identify and characterise the PEL and its surroundings. 3. Landing simulation for mission engineering purpose, based on shadow and reflection simulation on a fractal enhanced DEM model. The results of the work reported in this paper can be applied to future precursor missions to a human lunar outpost. It was performed in the framework of ESA’s LEDA and Euromoon 2000 studies. Processing of all relevant Clementine satellite images as well as a detailed radar picture from the Arecibo telescope resulted in the identification of two 'mountain tops' that most likely habitat a 'Peak of Eternal Light'. One 'mountain top' is located at the crossing of the western rim of crater Shackleton and a small 3 km diameter crater. The second 'mountain top' is located about 8 kilometres west of the rim of Shackleton. Consistency is shown with the expected characteristics of a PEL. Implications for engineering are discussed.