scholarly journals Photometric properties of lunar regolith revealed by the Yutu-2 rover

2020 ◽  
Vol 638 ◽  
pp. A35 ◽  
Author(s):  
Honglei Lin ◽  
Yazhou Yang ◽  
Yangting Lin ◽  
Yang Liu ◽  
Yong Wei ◽  
...  
Keyword(s):  
Near Infrared ◽  
Surface Composition ◽  
Lunar Regolith ◽  
Remote Sensing Data ◽  
Landing Site ◽  
Ground Truth ◽  
Wavelength Dependence ◽  
Forward Scattering ◽  
Small Scale ◽  
The Moon

Context. The surface composition of the Moon has mainly determined based on the visible and near-infrared spectra achieved from orbits and/or landing sites, and the spectroscopic analysis is based on photometric properties of the topmost lunar regolith. However, the lack of a ground truth for the photometric parameters of the undisturbed lunar surface has limited accurate applications of spectral observations. Aims. Here we report the photometric properties of the small-scale (i.e., centimeter level) undisturbed lunar regolith around the Chang’E-4 landing site, determined from a series of photometric experiments conducted by the rover Yutu-2. Methods. The simplified Hapke model was used to derive the photometric properties. The micro-topographic effect on the spectral measurements was corrected for the first time in the in situ photometric investigations on the Moon, which improves the accuracy of the derived photometric parameters. Results. The single-scattering albedo w and two parameters (b, c) of the Henyey-Greenstein phase function were derived, and they show a wavelength dependence. The regolith at the Chang’E-4 landing site exhibits strong forward scattering according to the retrieved c values, and the higher asymmetry parameter indicates that the regolith here is more strongly forward scattering than the Apollo lunar soil samples. The derived photometric parameters can serve as ground truth and can be used in the radiative transfer modeling analysis of the orbital remote-sensing data.

scholarly journals Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

2020 ◽  
Vol 13 (1) ◽  
pp. 48
Author(s):  
Hanjie Song ◽  
Chao Li ◽  
Jinhai Zhang ◽  
Xing Wu ◽  
Yang Liu ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Lunar Regolith ◽  
Landing Site ◽  
Rock Properties ◽  
The Moon ◽  
Local Correlation ◽  
Near Surface ◽  
Property Analysis ◽  
Stratigraphic Division ◽  
Formation And Evolution

The Lunar Penetrating Radar (LPR) onboard the Yutu-2 rover from China’s Chang’E-4 (CE-4) mission is used to probe the subsurface structure and the near-surface stratigraphic structure of the lunar regolith on the farside of the Moon. Structural analysis of regolith could provide abundant information on the formation and evolution of the Moon, in which the rock location and property analysis are the key procedures during the interpretation of LPR data. The subsurface velocity of electromagnetic waves is a vital parameter for stratigraphic division, rock location estimates, and calculating the rock properties in the interpretation of LPR data. In this paper, we propose a procedure that combines the regolith rock extraction technique based on local correlation between the two sets of LPR high-frequency channel data and the common offset semblance analysis to determine the velocity from LPR diffraction hyperbola. We consider the heterogeneity of the regolith and derive the relative permittivity distribution based on the rock extraction and semblance analysis. The numerical simulation results show that the procedure is able to obtain the high-precision position and properties of the rock. Furthermore, we apply this procedure to CE-4 LPR data and obtain preferable estimations of the rock locations and the properties of the lunar subsurface regolith.

Spectral mineralogy of terrestrial planets: scanning their surfaces remotely

1989 ◽  
Vol 53 (370) ◽  
pp. 135-151 ◽  
Author(s):  
Roger G. Burns
Keyword(s):  
Near Infrared ◽  
Surface Composition ◽  
Reflectance Spectra ◽  
Terrestrial Planets ◽  
The Moon ◽  
Spectral Measurements ◽  
Absorption Bands ◽  
Bearing Materials ◽  
Solar System Bodies ◽  
Surface Mineralogy

AbstractSpectral measurements of sunlight reflected from planetary surfaces, when correlated with experimental visible-near-infrared spectra of rock-forming minerals, are being used to detect transition metal cations, to identify constituent minerals, and to determine modal mineralogies of regoliths on terrestrial planets. Such remote-sensed reflectance spectra measured through earth-based telescopes may have absorption bands in the one micron and two micron wavelength regions which originate from crystal field transitions within Fe2+ ions. Pyroxenes with Fe2+ in M2 positions dominate the spectra, and the resulting 1 μm versus 2 µm spectral determinative curve is used to identify compositions and structure-types of pyroxenes on surfaces of the Moon, Mercury, and asteroids, after correcting for experimentally-determined temperature-shifts of peak positions. Olivines and Fe2+-bearing plagioclase feldspars also give diagnostic peaks in the 1 µm region, while tetrahedral Fe2+ in glasses absorb in the 2 µm region as well. Opaque ilmenite, spinel and metallic iron phases mask all of these Fe2+ spectral features. Laboratory studies of mixed-mineral assemblages enable coexisting Fe2+ phases to be identified in remote-sensed reflectance spectra of regoliths. Thus, noritic rocks in the lunar highlands, troctolites in central peaks of impact craters such as Copernicus, and high-Ti and low-Ti mare basalts have been mapped on the Moon's surface by telescopic reflectance spectroscopy. The Venusian atmosphere prevents remote-sensed spectral measurements of its surface mineralogy, while atmospheric CO2 and ferric-bearing materials in the regolith on Mars interfere with pyroxene characterization in bright- and dark-region spectra. Reflectance spectral measurements of several meteorite types, including specimens from Antarctica, are consistent with a lunar highland origin for achondrite ALHA 81005 and a martian origin for shergottite EETA 79001, although source regions may not be outermost surfaces of the Moon and Mars. Correlations with asteroid reflectance spectra suggest that Vesta is the source of basaltic achondrites, while wide ranges of olivine/pyroxene ratios are inconsistent with an ordinary-chondrite surface composition of many asteroids. Visible-near-infrared spectrometers are destined for instrument payloads in future spacecraft missions to neighbouring solar system bodies.

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars.

2021 ◽  
Author(s):  
Benjamin Bultel ◽  
Agata Krzesinska ◽  
Damien Loizeau ◽  
François Poulet ◽  
Håkon O. Astrheim ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Remote Sensing Data ◽  
Ground Truth ◽  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Mineral Assemblages ◽  
Alteration Minerals

<p>Serpentinization and carbonation have affected ultramafic rocks on Noachian Mars in several places. Among the most prominent systems revealing mineral assemblages characteristic of serpentinization/carbonation is the Nili Fossae region [1]. Jezero crater – the target of the Mars 2020 rover –hosted a paleolake which constitutes a sink for sediments from Nili Fossae [1]. Thanks to the near infrared spectrometer onboard Mars2020 [2], the mission has the potential to offer ground truth measurement for other putative serpentinization/carbonation system documented on Mars. Several important aspects that may be addressed are: Do carbonates result from primary alteration of olivine-rich lithologies or are they derived by reprocessing of previous alteration minerals [3]? What is the composition? and nature of the protolith, which appear to be constituted of considerable amounts of olivine [4]? To reveal critical information regarding the conditions of serpentinization/carbonation, accessory minerals need detailed studies [1; 5]. In case of Jezero Crater, and serpentinization on Mars in general, the main alteration minerals are identified, but little is known about the accessory minerals.</p><p>The Nili Fossae-Jezero system has potential analogues in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Norway (PTAL collection, https://www.ptal.eu). Here, distinct mineral assemblages record different stages of hydration and carbonation of ultramafic rocks [6].</p><p>We perform petrological and mineralogical analyses on thin sections to characterize the major and trace minerals and combine with Near Infrared (NIR) spectroscopy measurements. We study the significance of the mineralogical assemblages including solid solution composition and nature of accessory minerals. Effect of the presence of accessory minerals on the NIR signal is investigated and their potential incidence on the amount of H<sub>2</sub>/CH<sub>4</sub> production in mafic or ultramafic system is discussed [5; 8]. This could improve our understanding of serpentinization and carbonation processes on Mars, which can guide future in-situ operations and also help for a better interpretation of the remote sensing data acquired on other possible serpentinization/carbonation systems.</p><p><strong> </strong>References:</p><p>1. Brown, A. J., et al. EPSL297.1-2 (2010): 174-182.</p><p><span>2. Wiens, R.C., et al.  Space Sci Rev217</span><strong>, </strong><span>4 (2021).</span></p><p>3. Horgan, B., et al. Second International Mars Sample Return. Vol. 2071. 2018.</p><p>4. Ody, A., et al. JGR: Planets118.2 (2013): 234-262.</p><p>5. Klein, F., et al. Lithos178 (2013): 55-69.</p><p>6. Bjerga, A., et al. Lithos227 (2015): 21-36.</p><p>7. Bultel, B. (Doctoral dissertation, Lyon). (2016).</p>

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars

2020 ◽  
Author(s):  
Benjamin Bultel ◽  
Agata M. Krzesińska ◽  
Damien Loizeau ◽  
Cateline Lantz ◽  
François Poulet ◽  
...  
Keyword(s):  
Near Infrared ◽  
Remote Sensing Data ◽  
Landing Site ◽  
Ophiolite Complex ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Crucial Information ◽  
Alteration Minerals ◽  
System 1 ◽  
Mineralogical Assemblage

<p>Jezero Crater is the landing site of the Mars2020 NASA rover. The crater in its early history hosted a paleolake with at least two deltas remaining. The Jezero lake belongs to a larger system - the Nili Fossae region – which exposes a mineralogical assemblage interpreted as a serpentinization/carbonation system [1].  While the main alteration minerals in Jezero are identified, little is known about the accessory minerals. The latter could reveal critical information about the conditions of serpentinization/carbonation [2; 3]. Moreover, several aspects are yet to be solved: Are the carbonates resulting of primary alteration or reworked origin [4]? Is the mineralogical assemblage modified after deposition in the lake (weathering)? What is the nature of the protolith that could contains up to 30% of olivine [5]?</p><p>The Nili Fossae-Jezero system has its potential analogue in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Leka Island, Norway, (PTAL collection, https://www.ptal.eu), which records complex weathering of serpentinite formed from mafic to ultramafic rock [6].</p><p>We perform petrological and mineralogical analyses on thin sections to characterize the weathering products in Leka samples, and combine with Near Infrared Spectroscopy measurements. We study the significance of the mineralogical assemblages including solid solution composition and nature of accessory minerals. The consequence for habitability potential might be important. Indeed, the amount of H<sub>2</sub>/CH<sub>4</sub> production in mafic or ultramafic system vary significantly [2; 7]. This could represent crucial information that could guide future in-situ operations but could also help for a better interpretation of the remote sensing data.</p><p><strong> </strong></p><p>References:</p><ol><li>Brown, A. J., et al. EPSL297.1-2 (2010): 174-182.</li> <li>Klein, F., et al. Lithos178 (2013): 55-69.</li> <li>Gysi, A. P., & A. Stefánsson. GCA75.17 (2011): 4728-4751.</li> <li>Horgan, B., et al. Second International Mars Sample Return. Vol. 2071. 2018.</li> <li>Ody, A., et al. JGR: Planets118.2 (2013): 234-262.</li> <li>Bjerga, A., et al. Lithos227 (2015): 21-36.</li> <li>Bultel, B. (Doctoral dissertation, Lyon). (2016).</li> </ol>

scholarly journals Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool

2019 ◽  
Vol 7 (5) ◽  
pp. 913-920 ◽  
Author(s):  
Honglei Lin ◽  
Zhiping He ◽  
Wei Yang ◽  
Yangting Lin ◽  
Rui Xu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Lunar Regolith ◽  
Thermal Conditions ◽  
Landing Site ◽  
Lunar Crust ◽  
Imaging Spectrometer ◽  
Melt Pool ◽  
Moon Mineralogy Mapper ◽  
The Impact

Abstract Chang’E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith's composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730–43].

A discussion on infared astronomy - Mid-infrared spectroscopic observations of the Moon

1969 ◽  
Vol 264 (1150) ◽  
pp. 109-139 ◽  
Keyword(s):  
Remote Sensing ◽  
Lunar Surface ◽  
Wavelength Region ◽  
Landing Site ◽  
Ground Truth ◽  
Molecular Vibration ◽  
The Moon ◽  
Mid Infrared ◽  
Surface Materials ◽  
Remote Sensing Techniques

Now that space probes have actually landed on the Moon, and man is soon to follow, one might suppose that the need for the development of lunar remote sensing techniques is past. Exactly the opposite is true. It must be remembered that no nation is financially able to support exploration of more than a very small percentage of the total surface area of the moon. Small areas immediately adjacent to a landing site will, of course, be explored in detail. Hopefully, there will be a few traverses made to discover the degree of lateral inhomogeneity of the surface materials. Realistically, however, we must plan on extending this ‘ground truth’ information to cover the entire lunar surface by remote means. In fact, remote sensing techniques will be employed prior to much of the detailed lunar surface exploration in order to define areas of maximum interest. The mid-infrared region of the spectrum is a wavelength region which possesses a high potential usefulness for remote sensing, because the molecular vibration spectra in this region are directly interpretable in terms of molecular composition. It is the purpose of this paper to examine this potential, review the theoretical justification for use of this wavelength region, describe laboratory studies of possible lunar surface materials, and present the data so far obtained from the moon itself.

scholarly journals Uncertainty Introduced by Darkening Agents in the Lunar Regolith: An Unmixing Perspective

2021 ◽  
Vol 13 (22) ◽  
pp. 4702
Author(s):  
Marcel Hess ◽  
Thorsten Wilhelm ◽  
Christian Wöhler ◽  
Kay Wohlfarth
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Lunar Regolith ◽  
Spectral Unmixing ◽  
Probabilistic Methods ◽  
Space Weathering ◽  
The Moon ◽  
Absorption Bands ◽  
Diagnostic Features ◽  
Infrared Wavelength

On the Moon, in the near infrared wavelength range, spectral diagnostic features such as the 1-μm and 2-μm absorption bands can be used to estimate abundances of the constituent minerals. However, there are several factors that can darken the overall spectrum and dampen the absorption bands. Namely, (1) space weathering, (2) grain size, (3) porosity, and (4) mineral darkening agents such as ilmenite have similar effects on the measured spectrum. This makes spectral unmixing on the Moon a particularly challenging task. Here, we try to model the influence of space weathering and mineral darkening agents and infer the uncertainties introduced by these factors using a Markov Chain Monte Carlo method. Laboratory and synthetic mixtures can successfully be characterized by this approach. We find that the abundance of ilmenite, plagioclase, clino-pyroxenes and olivine cannot be inferred accurately without additional knowledge for very mature spectra. The Bayesian approach to spectral unmixing enables us to include prior knowledge in the problem without imposing hard constraints. Other data sources, such as gamma-ray spectroscopy, can contribute valuable information about the elemental abundances. We here find that setting a prior on TiO2 and Al2O3 can mitigate many of the uncertainties, but large uncertainties still remain for dark mature lunar spectra. This illustrates that spectral unmixing on the Moon is an ill posed problem and that probabilistic methods are important tools that provide information about the uncertainties, that, in turn, help to interpret the results and their reliability.

Small-scale vegetation mapping of large territories: perspectives of using modern remote sensing and GIS technologies, the Indian experiences

1996 ◽  
pp. 51-54 ◽  
Author(s):  
N. V. M. Unni
Keyword(s):  
Remote Sensing ◽  
Satellite Remote Sensing ◽  
Forest Cover ◽  
Human Life ◽  
Remote Sensing Data ◽  
Modern World ◽  
Small Scale ◽  
Vegetation Map ◽  
Gis Technologies ◽  
Forest Cover Mapping

The recognition of versatile importance of vegetation for the human life resulted in the emergence of vegetation science and many its applications in the modern world. Hence a vegetation map should be versatile enough to provide the basis for these applications. Thus, a vegetation map should contain not only information on vegetation types and their derivatives but also the geospheric and climatic background. While the geospheric information could be obtained, mapped and generalized directly using satellite remote sensing, a computerized Geographic Information System can integrate it with meaningful vegetation information classes for large areas. Such aft approach was developed with respect to mapping forest vegetation in India at. 1 : 100 000 (1983) and is in progress now (forest cover mapping at 1 : 250 000). Several review works reporting the experimental and operational use of satellite remote sensing data in India were published in the last years (Unni, 1991, 1992, 1994).

scholarly journals Understanding Vine Hyperspectral Signature through Different Irrigation Plans: A First Step to Monitor Vineyard Water Status

2021 ◽  
Vol 13 (3) ◽  
pp. 536
Author(s):  
Eve Laroche-Pinel ◽  
Mohanad Albughdadi ◽  
Sylvie Duthoit ◽  
Véronique Chéret ◽  
Jacques Rousseau ◽  
...  
Keyword(s):  
Near Infrared ◽  
Water Status ◽  
Vegetation Indices ◽  
Remote Sensing Data ◽  
Short Wave ◽  
Spatial And Temporal Scales ◽  
Spectral Bands ◽  
Main Challenge ◽  
Spectral Scale ◽  
Grape Varieties

The main challenge encountered by Mediterranean winegrowers is water management. Indeed, with climate change, drought events are becoming more intense each year, dragging the yield down. Moreover, the quality of the vineyards is affected and the level of alcohol increases. Remote sensing data are a potential solution to measure water status in vineyards. However, important questions are still open such as which spectral, spatial, and temporal scales are adapted to achieve the latter. This study aims at using hyperspectral measurements to investigate the spectral scale adapted to measure their water status. The final objective is to find out whether it would be possible to monitor the vine water status with the spectral bands available in multispectral satellites such as Sentinel-2. Four Mediterranean vine plots with three grape varieties and different water status management systems are considered for the analysis. Results show the main significant domains related to vine water status (Short Wave Infrared, Near Infrared, and Red-Edge) and the best vegetation indices that combine these domains. These results give some promising perspectives to monitor vine water status.

scholarly journals Fully-automated root image analysis (faRIA)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Narendra Narisetti ◽  
Michael Henke ◽  
Christiane Seiler ◽  
Astrid Junker ◽  
Jörn Ostermann ◽  
...  
Keyword(s):  
Near Infrared ◽  
Climatic Factors ◽  
Plant Root ◽  
Ground Truth ◽  
Parameter Tuning ◽  
Dice Coefficient ◽  
Powerful Analytical Tool ◽  
Manual Interaction ◽  
And Function ◽  
Noisy Background

AbstractHigh-throughput root phenotyping in the soil became an indispensable quantitative tool for the assessment of effects of climatic factors and molecular perturbation on plant root morphology, development and function. To efficiently analyse a large amount of structurally complex soil-root images advanced methods for automated image segmentation are required. Due to often unavoidable overlap between the intensity of fore- and background regions simple thresholding methods are, generally, not suitable for the segmentation of root regions. Higher-level cognitive models such as convolutional neural networks (CNN) provide capabilities for segmenting roots from heterogeneous and noisy background structures, however, they require a representative set of manually segmented (ground truth) images. Here, we present a GUI-based tool for fully automated quantitative analysis of root images using a pre-trained CNN model, which relies on an extension of the U-Net architecture. The developed CNN framework was designed to efficiently segment root structures of different size, shape and optical contrast using low budget hardware systems. The CNN model was trained on a set of 6465 masks derived from 182 manually segmented near-infrared (NIR) maize root images. Our experimental results show that the proposed approach achieves a Dice coefficient of 0.87 and outperforms existing tools (e.g., SegRoot) with Dice coefficient of 0.67 by application not only to NIR but also to other imaging modalities and plant species such as barley and arabidopsis soil-root images from LED-rhizotron and UV imaging systems, respectively. In summary, the developed software framework enables users to efficiently analyse soil-root images in an automated manner (i.e. without manual interaction with data and/or parameter tuning) providing quantitative plant scientists with a powerful analytical tool.

Sign in / Sign up

Export Citation Format

Share Document