Satellite monitoring of volcanic activity typically includes four primary observations: (1) deformation and surface change, (2) gas emissions, (3) thermal anomalies, and (4) ash plumes. These phenomena are imaged by remote sensing data that span the electromagnetic spectrum, from microwave to ultraviolet energy and including visible and infrared wavelengths. The primary uses of satellite data in volcanology are forecasting, detecting, and tracking eruptive activity. Eruptions are often preceded by a number of indicators that are detectable from space, including surface deformation, subtle increases in surface temperature, and elevated gas emissions. The first indications of eruption, especially at remote volcanoes, are often identified in satellite data by strong thermal anomalies and/or the presence of ash and gas in the atmosphere, the recognition of which can be automated for rapid eruption detection. Once an eruption is in progress, space-based imagery of all types can track activity over time, providing information on the emplacement of volcanic deposits, the presence and character of ash plumes, and potential changes in the character of the eruption, all of which aid hazards assessment. Activity at Agung volcano, Indonesia, during 2017–2019, offers an excellent example of the importance of remote sensing datasets for forecasting, detecting, and tracking eruptions. Challenges to exploiting current and future satellite data include ensuring regular acquisitions over active volcanoes and developing tools for automated analysis of the massive volume of imagery for volcano-related signals.

Forecasting, Detecting, and Tracking Volcanic Eruptions from Space

The last decade has seen a dramatic increase in small satellite missions for commercial, public, and government intelligence applications Given the rapid commercialization of constellation-driven services in Earth Observation, situational domain awareness, communications including machine-to-machine interface, exploration etc, small satellites represent an enabling technology for a large growth market generating truly Big Data Examples of modern sensors that can generate very large amounts of data are optical sensing, hyperspectral, Synthetic Aperture Radar (SAR), and Infrared imaging Traditional handling and downloading of Big Data from space requires a large onboard mass storage and high bandwidth downlink with a trend towards optical links Many missions and applications can benefit significantly from onboard cloud computing similarly to Earth-based cloud services Hence, enabling space systems to provide near real-time data and enable low latency distribution of critical and time sensitive information to users In addition, the downlink capability can be more effectively utilized by applying more onboard processing to reduce the data and create high value information products This paper discusses current implementations and roadmap for leveraging high performance computing tools and methods on small satellites with radiation tolerant hardware This includes runtime analysis with benchmarks of convolutional neural networks and matrix multiplications using industry standard tools (eg, TensorFlow and PlaidML) In addition, a ½ CubeSat volume unit (05U) (10 × 10 × 5 cm3) cloud computing solution, called SpaceCloud™ iX5100 based on AMD 28 nm APU technology is presented as an example of heterogeneous computer solution An evaluation of the AMD 14 nm Ryzen APU is presented as a candidate for future advanced onboard processing for space vehicles

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Enabling radiation tolerant heterogeneous GPU-based onboard data processing in space

We present a new formalism to describe the outgassing of hydrogen initially implanted by the solar wind protons into exposed soils on airless bodies. The formalism applies a statistical mechanics approach similar to that applied recently to molecular adsorption onto activated surfaces. The key element enabling this formalism is the recognition that the inter-atomic potential between the implanted H and regolith-residing oxides is not of singular value, but possess a distribution of trapped energy values at a given temperature, F(U, T). All subsequent derivations of the outward diffusion and H retention rely on the specific properties of this distribution. We find that solar wind hydrogen can be retained if there are sites in the implantation layer with activation energy values exceeding 0.5 eV. We especially examine the dependence of H retention applying characteristic energy values found previously for irradiated silica and mature lunar samples. We also apply the formalism to two cases that differ from the typical solar wind implantation at the Moon. First, we test for a case of implantation in magnetic anomaly regions where significantly lower energy ions of solar wind origin are expected to be incident with the surface. In magnetic anomalies, H retention is found to be reduced due to the reduced ion flux and shallower depth of implantation. Second, we also apply the model to Phobos where the surface temperature range is not as extreme as the Moon. We find the H atom retention in this second case is higher than the lunar case due to the reduced thermal extremes (that reduces outgassing).

The Statistical Mechanics of Solar Wind Hydroxylation at the Moon

Imaging Infrared Spectrometer (IIRS) on-board Chandrayaan-2 is designed to measure lunar reflected and emitted solar radiation in 0.8–5.0 μmm spectral range. Its high spatial resolution (~80 m) and extended spectral range is most suitable to completely characterize lunar hydration (2.8–3.5 μmm region) attributed to the presence of OH and/or H 2 O. Here we present initial results from IIRS reflectance data analysed to unambiguously detect and quantify lunar 3 μmm absorption feature. After pre-processing and data-reduction, a physics based thermal correction analysis of IIRS reflectance spectra has been done using co-located temperature measurements. Hydration absorption was observed at all latitudes and surface types with varying degrees for all pixels in the study area and its absorption depth shows distinct variability associated with mineralogy, surface temperature and latitude.

Unambiguous detection of OH and H 2 O on the Moon from Chandrayaan-2 Imaging Infrared Spectrometer reflectance data using 3 μm hydration feature

Water ice, abundant in the outer solar system, is volatile in the inner solar system. On the largest airless bodies of the inner solar system (Mercury, the Moon, Ceres), water can be an exospheric species but also occurs in its condensed form. Mercury hosts water ice deposits in permanently shadowed regions near its poles that act as cold traps. Water ice is also present on the Moon, where these polar deposits are of great interest in the context of future lunar exploration. The lunar surface releases either OH or H2O during meteoroid showers, and both of these species are generated by reaction of implanted solar wind protons with metal oxides in the regolith. A consequence of the ongoing interaction between the solar wind and the surface is a surficial hydroxyl population that has been observed on the Moon. Dwarf planet Ceres has enough gravity to have a gravitationally-bound water exosphere, and also has permanently shadowed regions near its poles, with bright ice deposits found in the most long-lived of its cold traps. Tantalizing evidence for cold trapped water ice and exospheres of molecular water has emerged, but even basic questions remain open. The relative and absolute magnitudes of sources of water on Mercury and the Moon remain largely unknown. Exospheres can transport water to cold traps, but the efficiency of this process remains uncertain. Here, the status of observations, theory, and laboratory measurements is reviewed.

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Water Group Exospheres and Surface Interactions on the Moon, Mercury, and Ceres

Christiansen Feature Map From the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment: Improved Corrections and Derived Mineralogy

Prior to 2009, the Moon was believed to be anhydrous. However, observations by three spacecraft revealed a hydrated surface by reporting a 3 µm absorption band attributed to hydroxyl and poss...

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JE006484

Telescopic Observations of Lunar Hydration: Variations and Abundance

The HyTI (Hyperspectral Thermal Imager) mission, funded by NASA’s Earth Science Technology Office InVEST (In-Space Validation of Earth Science Technologies) program, will demonstrate how high spectral and spatial long-wave infrared image data can be acquired from a 6U CubeSat platform. The mission will use a spatially modulated interferometric imaging technique to produce spectro-radiometrically calibrated image cubes, with 25 channels between 8-10.7 μm, at a ground sample distance of ~70 m. The HyTI performance model indicates narrow band NEΔTs of <0.3 K. The small form factor of HyTI is made possible via the use of a no-moving-parts Fabry-Perot interferometer, and JPL’s cryogenically-cooled BIRD FPA technology. Launch is scheduled for no earlier than October 2020. The value of HyTI to Earth scientists will be demonstrated via on-board processing of the raw instrument data to generate L1 and L2 products, with a focus on rapid delivery of precision agriculture metrics.

/pdf/hyti-thermal-hyperspectral-imaging-from-a-cubesat-platform-44vwktfzul.pdf

HyTI: Thermal Hyperspectral Imaging from A Cubesat Platform

https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.13715

A. Flom

Papers

Christiansen Feature Map From the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment: Improved Corrections and Derived Mineralogy

Telescopic Observations of Lunar Hydration: Variations and Abundance

HyTI: Thermal Hyperspectral Imaging from A Cubesat Platform

Multispectral imaging and hyperspectral scanning of the first dissection of core 73002: Preliminary results

Low mass LWIR hyperspectral imagers using microbolometers and Fabry-Perot interferometers