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NASA NTRS2019

Innovative Approaches to Using the International Space Station as a Mars Transit Analog

Human research on the International Space Station (ISS) crew has made significant advances in understanding of the effects of physiology on human health in space missions. However, ISS has not been as suitable for research on other hazards of human spaceflight such as isolation and communications delay. NASA recently completed a special assessment of whether modifications could be made to operations or facilities so that ISS could be used more effectively as an analog to simulate long-duration crew missions beyond low earth orbit. A cross-disciplinary team met to identify concept of operations, trade spaces, challenges, and opportunities to making ISS more operationally relevant as a Mars transit mission analog, and the results and implementation plans are summarized in this manuscript. In addition to the use case of 12-month missions (already in planning by the NASA ISS Program to bound expected Mars transit durations), three new use cases where ISS could provide valuable high-fidelity experience were identified. (1) Testing of operations procedures and medical care could be enhanced by demonstrating crew handling a simulated medical event in microgravity, autonomously, and with significant communications delay. (2) Isolation and confinement effects of deep space transit could be studied on ISS to validate current habitable volume requirements for Mars transit as well as provide context for evaluating the results of the extensive ground-based simulations in HERA and NEK. A trade study of possible operational and hardware changes that would make ISS applicable to these use cases was completed. (3) Surface operations after the physiological deconditioning of a long transit could be conducted to validate crew ability to perform critical ground tasks after 6-month Mars transit and aid in conceptual design of Mars surface element architectures. Each of the case studies includes a trade space between operational impacts on nominal ISS activities and degree of fidelity. A phased approach to implementation means that several "quick start" activities can be done in 2019-2020 at the same time as planning continues for more complex exploration analog options beginning as early as 2022. The team determined that many of these quick-start tasks could be done with available assets, entirely independent of other exploration system development timelines (such as Orion, Space Launch System). The consideration of the full suite of human spaceflight capabilities in the lunar vicinity can also be included as each step in human exploration serves as a simulation opportunity for some aspect of subsequent missions. Further discussions of options with the international community are critical for considering the benefits as well as impacts of simulation activities on ISS, as well as to better formulate future mission architectures.

Robinson, Julie A.↗
NASA NTRS2019

Introducing NASA Ames' New Infrared Optical Constant Facility. Determinations of Complex Refractive Indices for Titan Aerosol Analogs and Other Applications

A new optical constant facility has been developed at NASA Ames that will allow the determination of optical constants in the infrared of various materials, analogs of (exo)planetary hazes and cloud particles. Our facility is composed of a Fourier Transform Infrared (FTIR) spectrometer continuously covering the Near-IR to Far-IR range (from 0.74 to 200 μm), coupled to variable angle transmittance and reflectance accessories that allow the characterization of the scattering properties of non-homogeneous samples (laboratory (exo)planetary aerosol analogs, films, slabs of material, crystals, powders, etc.) over a wide incidence and emittance angle range (0-90 degrees). This new experimental setup allows the characterization of angular light distribution in both transmission and reflection measurements, and enables the determination of the complex indices of refraction, n and k, over the full NIR-FIR range via modeling of the laboratory measurements. The resulting refractive indices are critical input parameters in radiative transfer models, microphysical models, cloud models, protoplanetary disk simulations and other models used for the interpretation of observational data from past, current and future (exo)planetary NASA missions. Here we present a description of the facility along with the first determination of optical constants for Titan aerosol analogs produced in the Titan Haze Simulation (THS) experiment on COSmIC, a unique experimental setup developed at NASA Ames that allows the simulation of Titan’s complex atmospheric chemistry at Titan-like temperature (200 K). We also introduce a new study of the optical properties of ammonium-bearing phosphates, potential cloud particles forming in temperate exoplanets and brown dwarfs.

Sciamma-O'Brien, Ella M.↗
NASA NTRSDate not supplied

Low-Temperature Production of Cosmic Grains Analogs From Gas-Phase Molecular Precursors with the NASA Ames' COSmIC Facility

Complex carbon molecules and ions are ubiquitous in space and form the building blocks of carbonaceous cosmic dust grains, ultimately contributing to the formation of planets. Here, we report the first experimental investigations of the low temperature chemical pathways leading to the production of cosmic grain analogs from gas phase molecular precursors in order to better understand the evolution of cosmic carbon. The experiments were performed using the COsmic SImulation Chamber (COSmIC) to generate and characterize grains formed from gas phase precursors under controlled conditions representative of astrophysical environments [1]. Using COSmIC, it is possible to investigate the evolution of cosmic carbon from the formation of neutral and ionized gas phase hydrocarbons and PAHs [2], to carbon grains [3, 4]. This is achieved by using a discharge nozzle to (1) produce an adiabatic jet expansion and cool down Ar-hydrocarbon/PAH gas mixtures to astrophysically relevant temperature (150 K) before inducing chemistry by generating a plasma discharge in the stream of the expansion. This plasma-induced chemistry results in the formation of complex molecules and solid particles, analogs of cosmic grains. Solid grains are produced in-situ in the plasma expansion, carried by the accelerated gas in the expansion, and collected on substrates placed a few centimeters downstream of the electrodes. The results of a preliminary solid phase ex-situ analysis of cosmic grain analogs produced at low temperature in COSmIC from gas mixtures including molecular precursors of cosmic carbon grains, i.e., such as CH4 and C2H2 found in circumstellar ejecta of late C stars [3] as well as PAHs ubiquitously detected in IR emission bands seen in galactic and extragalactic environments [4] will be discussed. Scanning Electron Microscopy imaging was used to provide insight on the morphology and growth structure of the grains produced in COSmIC, and to investigate how the precursors used to produce the grains affect these parameters [3]. Laser desorption mass spectrometry was used to identify the molecules making up the main structures within the condensed grains [4]. NIR to FIR optical properties are characterized to provide critical information (functional groups, optical constants) to the scientific community, for use in radiative transfer models in particular, and to help decipher and enhance the return data from space observations.

F. Salama↗
NASA NTRSDate not supplied

Thermal and Evolved Gas Analysis of Mars Analog Paleosols

Decades of space exploration have shown that three to four billion-year old surface environments on Mars may have been habitable. Ancient surface environments which resemble paleosols (buried sedimentary deposits which formed from subaerial weathering) on Mars have recently been named a high-priority target for biosignature investigation and Mars Sample Return because paleosol mineralogy records valuable information about past climates, and because Archean (~2.6 Ga) paleosols from Earth preserve some of the oldest biosignatures of life on land. However, there has been little effort to characterize terrestrial paleosols with Mars-like mineralogy using instruments analogous to those on current and future missions to Mars, which is imperative for understanding if putative paleosols on Mars should be targeted for future exploration. The objectives of this study were to perform the first comprehensive analysis of Mars-analog paleosols with Mars flight-analog instrumentation and to determine if organic carbon in these paleosols is detectable in the presence of a perchlorate salt.

A. P. Broz↗
NASA NTRS2021

Novel Ways to use the International Spacer Station as an Exploration Analog: International Progress in Planning "ISS4Mars"

In October 2020, International Space Station (ISS) Partner Agencies held a set of international workshops to solicit and develop creative and forward-looking ideas for using the ISS as an analog for preparation for Mars missions during its 3rd decade of operations. The workshops brought together participants from nine international space agencies or organizations, with stakeholders consisting of research managers, discipline experts, technology developers, flight physicians, flight operators, and astronauts. Breakout meetings and brainstorming sessions were conducted focusing on the following topics: Critical hazards and countermeasures for the transit to Mars; gravity transitions and early surface operations; environmental control and life support systems; food systems; human microbiome, microbial monitoring, and planetary protection; medical operations for Mars missions; isolation and confinement; autonomous systems and crew-centered autonomy; and communications delay effects on operations. In many cases the scenarios and approaches identified were compelling but challenging to implement under the current utilization structure used to manage the ISS for experiments. Following the series of workshops, a team of utilization leaders across the ISS partnership worked to compile the workshop recommendations and extract a set of use-cases with their prerequisites and constraints. The work considered the following aspects: what can be effectively done on ISS; which new technologies, approaches and scenarios are feasible; what alternatives could be considered; and what steps should be taken to enable integrated testing and future use of ISS as an analog for Mars missions. The final report will be published so that the use cases can be considered in each agency’s strategic planning processes. This paper will cover the process of international assessment in detail and how this process has influenced and broadened the vision of ISS utilization beyond single experiments to integrated studies and testing for future Mars missions. This approach to international collaboration informs both the next decade of international exploration research on the ISS and advancement of its utilization as an analog for deep space missions. For many of the participating partners, it also helps to frame the strategy for human research in Artemis as we begin planning for human missions to the moon. We conclude with a summary of the progress on the actions in the report and the additional implementation discussions that have occurred across the partnership.

Julie A Robinson↗
NASA NTRSDate not supplied

Principles for Termination of Medical Care in Austere Analog Environments for Development of Spaceflight Protocols

INTRODUCTION: When compared to operations in low earth orbit, exploration class missions will have substantially limited resources and ground medical support while the risk of a significant medical event is projected to be higher. Termination of care (TOC) may need to be considered in certain instances. We aim to utilize data from earth-based analogs to identify common principles that can help develop future guidelines to this complex medical and ethical challenge. METHODS: A comprehensive literature review was conducted in medline, nasa.gov, Defense Technical Information Center(DTIC) and google scholar. Key search terms including “withdrawal of care, termination of care, termination of CPR, military medicine, wilderness medicine, futility, potentially inappropriate” and others were used to identify analog studies of relevance. These were qualitatively evaluated for recurring principles or themes that were reviewed and structured. RESULTS: Mission planning termination of care principles: definitions of clear medical goals, separate protocols for each relevant condition, protocols developed using best available evidence, crew involvement in development, protocols rehearsal pre-launch, and inclusion of palliative capabilities. In-mission termination of care principles: 1. Crew Medical Officer directed stabilization of the patient; 2. Consultation with mission control with standardized information exchange; 3. Multidisciplinary medical and ethical conference among the mission directors, flight surgeons and relevant specialist experts; 4. Multidisciplinary risk review examining both medical and mission risks for relevant options; 5. Provision of a transparent explanation of the process and decision to crew; 6. Allowing crew feedback and inquiry to review board; 7. Support of the crew in the enacted decision. DISCUSSION: By utilizing the best available evidence in conjunction with expert opinion we have identified common principles from earth-based analogs that could be used to help design future TOC protocols.

Samuel Stephenson↗
NASA NTRSDate not supplied

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗
NASA NTRSDate not supplied

The Project “Analogs for VENus’s GEologically Recent Surfaces” (AVENGERS): Unveiling Active Volcanism on Venus

The recently selected missions to Venus opened a new era for the exploration of the Earth’s hellish twin sister. One of the key questions that the selected missions to Venus will address is whether the planet is volcanically active. The identification of ongoing volcanic activity on Venus can indeed unveil important clues on the geologic evolution of the planet, also helping us to better understand how volcanic and atmospheric processes work on Earth, especially those related to the climate change produced by greenhouse gases. To fully contextualize the higher resolution datasets to be provided by the future missions to Venus, we need to be able to exploit the wealth of data to be produced in the best possible way. Different types of instruments will indeed perform unprecedent orbiting and in-situ investigations of the surface and subsurface of Venus. To this regard, the Project “Analogs for VENus’s GEologically Recent Surfaces” (AVENGERS) aims to build a comprehensive database of Terrestrial active volcanoes which may act as suitable analogs for identifying ongoing volcanic activity on Venus. To do this, the project AVENGERS will combine the implementation of terrestrial orbiter radar data analysis techniques (i.e., radar interferometry) with infrared and laboratory analyses of lava flow samples from Terrestrial active volcanoes. As a first suitable analog of the Project AVENGERS, we selected Mount Etna in Sicily for a direct comparison with potentially active volcanic structures of Venus, and with Idunn Mons, one of the most promising possibly active volcanoes of Venus. Given its composite nature, Mount Etna offers the opportunity to identify and study multiple types of eruptive products (both effusive and explosive) from the analysis of high-resolution radar images. The frequent eruptions characterizing this volcano will also allow to test techniques of radar interferometry. Moreover, its ease of access facilitates geologic field trips and in-situ investigations with related sample retrieving. Ongoing infrared laboratory analysis on several altered and unaltered samples retrieved by Mount Etna will help to distinguish spectral signatures of fresh vs weathered volcanic deposits.

P. D’Incecco↗
NASA NTRSDate not supplied

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗
NASA NTRS2023

Palmer Station, Antarctica: A Ground-Based Spaceflight Analog Suitable for Validation of Biomedical Countermeasures for Deep Space Missions

Astronauts are known to exhibit a variety of immunological alterations during spaceflight including changes in leukocyte distribution and plasma cytokine concentrations, a reduction in T-cell function, and subclinical reactivation of latent herpesviruses. These alterations are most likely due to mission-associated stressors including circadian misalignment, microgravity, isolation, altered nutrition, and increased exposure to cosmic radiation. Some of these stressors may also occur in terrestrial situations. This study sought to determine if crewmembers performing overwinter deployment at Palmer Station, Antarctica displayed similar immune alterations. The larger goal was to validate a ground analog suitable for the evaluation of countermeasures designed to protect astronauts during future deep space missions. For this pilot study, plasma, saliva, hair, and health surveys were collected from Palmer Station, Antarctica winterover participants at baseline, and at five overwinter timepoints. Twenty-six subjects consented to participate over the course of two seasons. Initial sample processing was performed at Palmer, and eventually stabilized samples were returned to the Johnson Space Center for analysis. A white blood cell differential was performed (real time) using a fingerstick blood sample to determine alterations in basic leukocyte subsets throughout the winterover. Plasma and saliva samples were analyzed for 30 and 13 cytokines, respectively. Saliva was analyzed for cortisol concentration and three latent herpesviruses (DNA by qPCR), EBV, HSV1, and VZV. Hair samples were analyzed for several hormones, as a measure of stress over prolonged periods of time. Voluntary surveys related to general health and adverse clinical events were distributed to participants. It is noteworthy that due to logistical constraints due to COVID-19, the baseline samples for each season were collected in Punta Arenas, Chile, after long international travel and during isolation. Therefore, the palmer pre mission samples may not reflect a true normal ‘baseline’. Minimal alterations were observed in leukocyte distribution during overwinter. The mean percentage of monocyte concentration elevated at one timepoint. Plasma G-CSF, IL1RA, MCP-1, MIP-1β, TNFα and VEGF were decreased during at least one overwinter timepoint, whereas RANTES was significantly increased. No statistically significant changes were observed in mean saliva cytokine concentrations. Salivary cortisol was substantially elevated throughout the entire winterover compared to baseline. Compared to shedding levels observed in healthy controls (23%), the percentage of participants who shed EBV was higher throughout all winterover timepoints (52-60%). Five subjects shed HSV1 during at least one timepoint throughout the season compared to no subjects shedding during pre-deployment. Finally, VZV reactivation, common in astronauts but exceptionally rare in ground-based stress analogs, was observed in one subject during pre-deployment and a different subject at WO2 and WO3. These pilot data, somewhat influenced by the COVID-19 situation, do suggest that participants at Palmer Station do undergo immunological alterations similar to, but likely in reduced magnitude, as those observed in astronauts. We suggest that overwinter at Palmer Station may be suitable test analog for spaceflight biomedical countermeasures designed to mitigate clinical risks for deep space missions.

Space↗
NASA NTRSDate not supplied

Active Volcanoes of Kamchatka as Suitable Terrestrial Analogs for Future Landing Missions and for Change Detection Analysis on Venus

The next decade will see the return to Venus due to a number of missions which have been recently selected and proposed for launch. The selected missions NASA DAVINCI and VERITAS, Roscosmos Venera-D, and ESA EnVision, along with the proposed missions ISRO Shukrayaan- 1, and CNSA VOICE, will open a new era for the exploration of the Earth’s hellish twin planet. These missions will shed new light on the science questions such as: (a) whether recent volcanic activity is locally constrained, or active volcanism occurs on a global scale; (b) the rate of the present-day volcanic activity; (c) the styles of volcanism on Venus, including possible occurrences of pyroclastic/explosive volcanism; and (d) how does the extreme environment on Venus effect volcanic activity. In preparation for these future missions to Venus, the Analogs for VENus’ GEologically Recent Surfaces (AVENGERS) initiative has the scope to select and analyze a number of active terrestrial volcanoes as suitable analogs for the identification and analysis of active volcanism on Venus. The Roscosmos Venera-D is the only mission, among the currently selected or planned mission, equipped with a lander to analyze the elemental and mineralogical composition of the surface. Therefore, it is crucial to find applicable volcanic areas on Earth to perform operational tests such as surface drilling and in-situ elemental composition analysis. To this regard, we propose the analysis of active volcanoes of the Kamchatka Peninsula, which is in a geodynamic setting (subduction) contrasting to that of the volcanic rises on Venus (hot spot). Thus, Kamchatka may represent a helpful geodynamic endmember to put the expected landing site of the Venera-D mission within the context of the entire variety of volcanic landforms and surface chemistry. The Kamchatka Peninsula is located on the eastern margin of the Eurasian plate, in proximity to the Kuril-Kamchatka subduction zone. The frequent eruptions characterizing the volcanoes of the Kamchatka Peninsula make them a suitable terrestrial analog for the possible detection of ongoing eruptions on Venus by future missions, which can be achieved by comparing a sequence of radar images of the same volcano and its surroundings taken at different times. Moreover, it is possible to collect samples of both unweathered and weathered volcanic deposits, to analyze their near infrared spectra in the laboratory for direct comparison with the spectra to be provided by the future missions to Venus. The chemical analyses of Venusian surface materials from the previous Soviet Venera and Vega missions are consistent with that of tholeiitic basalts. Since the volcanism of the Kamchatka Peninsula is characterized by both basaltic lava flows eruptions and pyroclastic activity, performing operational tests in the Kamchatka Peninsula also offers the unique opportunity to provide us the tools to potentially interpret the diverse output given by both effusive and explosive volcanic products.

Piero D'Incecco↗
NASA NTRSDate not supplied

Jet Noise Modeling Using an Acoustic Analogy: From Theoretical Formulation to Practical Noise Predictions

In this presentation an overview of the development of an acoustic analogy formulation, and its implementation into a reduced-order prediction method for turbulent jet mixing noise, will be given. The definition and rationale of an acoustic analogy approach to the prediction of flow-generated noise will be provided. A high-level description of the mathematical processes involved will be outlined in the context of a particular formulation developed at NASA Glenn Research Center. The modelling approximations needed to implement the general theoretical formulation into a practical noise prediction tool will be discussed. Sample results obtained using a noise prediction code based on the NASA Glenn formulation, and comparisons with experimental data, will be presented for a series of turbulent jet test cases. A view on the prospects for continued use of acoustic analogy-based methods for the prediction of flow-generated noise and the assessment of noise-reduction technologies will conclude the presentation.

Jet noise↗
DOE OSTI2025

Dual-ion ECRAM as a stable and accurate analog synapse

Electrochemical random-access memory (ECRAM) works by tuning the bulk electronic conductance of functional materials via reversible, electrochemical insertion of ions, resulting in stable analog resistive switching, attractive for analog in-memory and neuromorphic computing. However, achieving fast programming for training and long retention for inference has been elusive. Protonic ECRAM demonstrates fast programming but insufficient retention, while oxygen-based ECRAM with excellent retention requires elevated programming temperatures. Cu-based ECRAM offers a compromise, with an activation energy (E A ) of ≈0.76 eV between protons (E A ≈ 0.4 eV) and oxygen (E A > 1 eV), enabling extensive retention and room temperature programming. Combining Cu 2+ ions with protons to form a dual-ion ECRAM, we demonstrate two distinct switching behaviors: fast switching at ≤5 V, (E A ≈ 0.45 eV) via protons, and nonvolatile, room temperature switching at ≥8 V, with E A ≈ 0.76 eV via Cu 2+ ions. In conclusion, the Cu-based state exhibits a wide conductance range, with excellent retention, low noise, and linear current-voltage behavior, achieving digital-equivalent ImageNet inference accuracy.

analog in-memory computing↗
NASA NTRS2012

The International Space Station: Unique In-Space Testbed as Exploration Analog

Final assembly of the International Space Station (ISS) was completed in 2011. As articulated in the 2011 NASA Strategic Plan, the Agency's first goal is to extend and sustain human activities across the solar system. Thus, the emerging NASA vision is to launch a bold and ambitious new space initiative to enable human space exploration beyond low-Earth orbit to Lagrange points, the moon, near-Earth asteroids (NEAs), and Mars and its environs. To accomplish this vision, it is necessary to develop and validate innovative exploration technologies and operational concepts. With the extended life of the ISS to 2020 and possibly 2028, NASA has a mandate to maximize the potential of the Nation's newest National Laboratory. Exploration and ISS teams within NASA's Human Exploration and Operations Mission Directorate (HEOMD) have initiated a cooperative effort: the ISS Testbed for Analog Research (ISTAR), a high-fidelity operational analog that complements existing NASA terrestrial laboratory and field testing. To maximize use of the ISS platform to evaluate new exploration technologies, capabilities, and operational concepts to better comprehend and mitigate human spaceflight risks, ISTAR seeks out and encourages investigations dubbed "exploration detailed test objectives" (xDTOs). These xDTOs, building blocks of ISTAR missions, develop and optimize the operations concepts and the use of new technologies that should reduce risks and challenges facing astronauts on long exploration spaceflight voyages. In this paper, we describe (1) the rationale behind ISTAR, (2) a five-year strategic plan, (3) the approach for mission formulation, development, integration, and execution, (4) concepts for near-term missions that implement a phased approach for using ISS as an exploration testbed, and (5) the planned Mars mission simulation using the ISS. This paper will also document several challenges ISTAR must address to execute its missions.

Analog Mission↗
DOE OSTI2020

Expanded Analogs of Three-Dimensional Lead-Halide Hybrid Perovskites

Replacing the Pb-X octahedral building unit of A I PbX 3 perovskites (X=halide) with a pair of edge-sharing Pb-X octahedra affords the expanded perovskite analogs: A II Pb 2 X 6 . We report seven members of this new family of materials. In 3D hybrid perovskites, orbitals from the organic molecules do not participate in the band edges. In contrast, the more spacious inorganic sublattice of the expanded analogs accommodates larger pyrazinium-based cations with low-lying π* orbitals that form the conduction band, substantially decreasing the band gap of the expanded lattice. The molecular nature of the conduction band allows us to electronically dope the materials by reducing the organic molecules. By synthesizing derivatives with AII=pyridinium and ammonium, we can isolate the contributions of the pyrazinium-based orbitals in the band gap transition of A II Pb 2 X 6 . The organic-molecule-based conduction band and the inorganic-ion-based valence band provide an unusual electronic platform with localized states for electrons and more disperse bands for holes upon optical or thermal excitation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Investigation of Stress Field and Fracture Development During Shale Maturation Using Analog Rock Systems

The emergence of hydrocarbons within shale as a major recoverable resource has sparked interest in fluid transport through these tight mudstones. Recent studies suggest the importance to recovery of microfracture networks that connect localized zones with large organic content to the inorganic matrix. This paper presents a joint modeling and experimental study to examine the onset, formation, and evolution of microfracture networks as shale matures. Both the stress field and fractures are simulated and imaged. A novel laboratory-scale, phase-field fracture propagation model was developed to characterize the material failure mechanisms that play a significant role during the shale maturation process. The numerical model developed consists of coupled solid deformation, pore pressure, and fracture propagation mechanisms. Benchmark tests were conducted to validate model accuracy. Laboratory-grade gelatins with varying Young’s modulus were used as scaled-rock analogs in two dimensional Hele-Shaw cell apparatus. Yeast within the gelatin generates gas in a fashion analogous to hydrocarbon formation as shale matures. These setups allow study and visualization of host rock elastic-brittle fracture and fracture network propagation mechanisms. The experimental setup was fitted to utilize photoelasticity principles coupled with birefringence properties of gelatin to explore visually the stress field of the gelatin as the fracture network developed. Stress optics image analysis and Linear Elastic Fracture Mechanics (LEFM) principles for crack propagation were used to monitor fracture growth for each gelatin type. Observed and simulated responses suggest gas diffusion within and deformation of the gelatin matrix as predominant mechanisms for energy dissipation depending on gelatin strength. LEFM, an experimental estimation of principal stress development with fracture growth, at different stages was determined for each gelatin rheology. Here, the interplay of gas diffusion and material deformation determines the resulting frequency and pattern of fractures. Results correlate with Young’s modulus. Experimental and computed stress fields reveal that fractures resulting from internal gas generation are similar to, but not identical to, type 1 opening mode.

58 GEOSCIENCES↗
DOE OSTI2011

Energy Savings Assessment for Digital-to-Analog Converter Boxes

The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2013

Natural CO 2 accumulations in the western Williston Basin: A mineralogical analog for CO 2 injection at the Weyburn site

The Devonian carbonates of the Duperow Formation on the western flank of the Williston Basin in southwest Saskatchewan contain natural accumulations of CO 2 , and may have done so for as long as 50 million years. These carbonate sediments are characterized by a succession of carbonate cycles capped by anhydrite-rich evaporites that are thought to act as seals to fluid migration. The Weyburn CO 2 injection site lies 400 km to the east in a series of Mississippian carbonates that were deposited in a similar depositional environment. That long-term isolation of natural CO 2 can be accomplished within carbonate strata has motivated the investigation of the Duperow rocks as a potential natural analog for storage of anthropogenic CO 2 in carbonate lithologies. For the Duperow strata to represent a legitimate analog for Midale injection and storage, the similarity in lithofacies, whole rock compositions, mineral compositions and porosity with the Midale Beds must be established. Here we compare lithofacies, whole rock compositions, mineralogy and mineral compositions from both locales. The major mineral phases at both locales are calcite, dolomite and anhydrite. In addition, accessory pyrite, fluorite, quartz and celestine (strontium sulfate) are also observed. Dawsonite, a potential CO 2 -trapping mineral, is not observed within the CO 2 -bearing horizons of the Duperow Formation, however. The distribution of porosity in the Midale Vuggy units is similar to that of the Duperow Formation, but the Marly units of the Midale have significantly higher porosity. The Duperow Formation is topped by the Dinesmore evaporite that is rich in anhydrite, and often contains authigenic K-feldspar. The chemistry of dolomite and calcite from the two localities also overlaps. Silicate minerals are in low abundance (<3%) within the analyzed Duperow samples, with quartz and K-feldspar the only silicates observed petrographically or in X-ray diffraction patterns. The Midale Beds contain significantly higher silica/silicate concentrations (Durocher et al., 2003), but the paucity of mono- and divalent cations that can be derived from dissolution of these silicate minerals likely precludes significant carbonate mineral formation. Therefore physical and solution trapping are likely to be the primary CO 2 trapping mechanisms at both sites.

58 GEOSCIENCES↗