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All sources NASA NTRS DOE OSTI

DOE OSTI2025

Tracking seasonal variability in plant traits from spaceborne PRISMA and NEON AOP across forest types and ecoregions

Plant traits serve as critical indicators of how plants adapt to environmental changes and influence ecosystem functions. While airborne hyperspectral remote sensing effectively maps plant traits through detailed reflectance properties, it is limited by cost and scale, making large-scale and temporal studies challenging. The recently launched spaceborne hyperspectral imager, PRecursore IperSpettrale della Missione Applicativa (PRISMA), offers frequent, large scale and high-fidelity observations on a spatial resolution of 30 m and a revisit time of around 29 days, making it suitable for large-scale seasonal trait mapping. However, their potential remains largely unexplored. This study developed a multi-stage framework by leveraging the PRISMA spaceborne hyperspectral data and National Ecological Observatory Network (NEON) Airborne Observation Platform (AOP) hyperspectral data to investigate the seasonal dynamics of four key plant traits — chlorophyll content, carotenoid content, equivalent water thickness, and nitrogen content — across eleven NEON sites representing diverse forest types and ecoregions in the contiguous U.S. Our results demonstrated that PRISMA hyperspectral data can reliably track seasonal variability in plant traits, achieving overall R 2 values ranging from 0.78 to 0.88 and normalized root mean square error (NRMSE) values ranging from 5.4% to 8.4% for the four traits. Seasonal patterns revealed bell-shaped trajectories for chlorophyll and carotenoids, while equivalent water thickness decreased steadily across most sites, driven by structural changes during leaf maturation and senescence. Nitrogen content exhibited less pronounced seasonal variation but followed expected nutrient resorption patterns. Analysis of environmental drivers showed that seasonal variability is primarily controlled by solar radiation and day length in northern sites, vapor pressure in semi-arid regions, and temperature in mid-southeastern sites. Spatial variability, meanwhile, was primarily driven by soil properties, particularly during the peak growing season. However, the influence of soil variables slightly declines toward the end of the season at several sites, as climatic factors become more prominent. This study highlights the capability of PRISMA, and potentially other similar spaceborne hyperspectral data for large-scale, time-series plant trait mapping and provides valuable insights into the interactions between plant traits and environmental factors. In conclusion, these findings contribute to advancing our understanding of plant functional ecology and improving predictions of ecosystem responses to environmental changes.

Environmental drivers↗

NASA NTRS1996

Re-Engineering JPL's Mission Planning Ground System Architecture for Cost Efficient Operations in the 21st Century

Work carried out to re-engineer the mission analysis segment of JPL's mission planning ground system architecture is reported on. The aim is to transform the existing software tools, originally developed for specific missions on different support environments, into an integrated, general purpose, multi-mission tool set. The issues considered are: the development of a partnership between software developers and users; the definition of key mission analysis functions; the development of a consensus based architecture; the move towards evolutionary change instead of revolutionary replacement; software reusability, and the minimization of future maintenance costs. The current status and aims of new developments are discussed and specific examples of cost savings and improved productivity are presented.

Fordyce, Jess↗

NASA NTRS1983

Environmental Control and Life Support for an evolutionary Space Station

The requirements for the Space Station are being defined. The Environmental Control/Life Support System (ECLSS) is one of its 13 systems. The ECLSS is further divided into five functional categories. Major ones are the Air Revitalization and Water Reclamation Systems. The paper presents ECLSS performance requirements, average design loads and fluids interfaces. The major cost savings of regenerable ECLSS techniques versus the open loop approach are quantified. Issues impacting ECLSS design are cited. Priority regenerable ECLSS developments are reviewed including the Electrochemical CO2 Concentrator, Static Feed Electrolyzer and Automated Control/Monitor Instrumentation. Baseline and alternative approaches are cited. The ECLSS planning issues are reviewed including functional boundaries, planning schedule, technology maturity definition and technology gaps. The paper concludes with a review of water electrolysis as a Space Station utility impacting ECLSS design.

Quattrone, P. D.↗

NASA NTRS1977

Analysis of economics of a TV broadcasting satellite for additional nationwide TV programs

The influence of a TV broadcasting satellite, transmitting four additional TV networks was analyzed. It is assumed that the cost of the satellite systems will be financed by the cable TV system operators. The additional TV programs increase income by attracting additional subscribers. Two economic models were established: (1) each local network is regarded as an independent economic unit with individual fees (cost price model) and (2) all networks are part of one public cable TV company with uniform fees (uniform price model). Assumptions are made for penetration as a function of subscription rates. Main results of the study are: the installation of a TV broadcasting satellite improves the economics of CTV-networks in both models; the overall coverage achievable by the uniform price model is significantly higher than that achievable by the cost price model.

Becker, D.↗

DOE OSTI2021

Velocity-Space Hybridization of Direct Simulation Monte Carlo and a Quasi-Particle Boltzmann Solver

This paper presents a new method for modeling rarefied gas flows based on hybridization of direct simulation Monte Carlo (DSMC) and discrete velocity method (DVM)-based quasi-particle representations of the velocity distribution function. It is aimed at improving the resolution of the tails of the distribution function (compared with DSMC) and computational efficiency (compared with DVM). Details of the method, such as the collision algorithm and the particle merging scheme, are discussed. The hybrid approach is applied to the study of noise in a Maxwellian distribution, computation of electron-impact ionization rate coefficient, as well as numerical simulation of a supersonic Couette flow. The hybrid-based solver is compared with pure DSMC and DVM approaches in terms of accuracy, computational speed, and memory use. It is shown that such a hybrid approach can provide a lower computational cost than a pure DVM approach, while being able to retain accuracy in modeling high-velocity tails of the distribution function. For problems where trace species have a significant impact on the flow physics, the proposed method is shown to be capable of providing better computational efficiency and accuracy compared with standard fixed-weight DSMC.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS2010

Propulsion System Choices and Their Implications

In defining a space vehicle architecture, the propulsion system and related subsystem choices will have a major influence on achieving the goals and objectives desired. There are many alternatives and the choices made must produce a system that meets the performance requirements, but at the same time also provide the greatest opportunity of reaching all of the required objectives. Recognizing the above, the SPST Functional Requirements subteam has drawn on the knowledge, expertise, and experience of its members, to develop insight that wiIJ effectively aid the architectural concept developer in making the appropriate choices consistent with the architecture goals. This data not only identifies many selected choices, but also, more importantly, presents the collective assessment of this subteam on the "pros" and the "cons" of these choices. The propulsion system choices with their pros and cons are presented in five major groups. A. System Integration Approach. Focused on the requirement for safety, reliability, dependability, maintainability, and low cost. B. Non-Chemical Propulsion. Focused on choice of propulsion type. C. Chemical Propulsion. Focused on propellant choice implications. D. Functional Integration. Focused on the degree of integration of the many propulsive and closely associated functions, and on the choice of the engine combustion power cycle. E. Thermal Management. Focused on propellant tank insulation and integration. Each of these groups is further broken down into subgroups, and at that level the consensus pros and cons are presented. The intended use of this paper is to provide a resource of focused material for architectural concept developers to use in designing new advanced systems including college design classes. It is also a possible source of input material for developing a model for designing and analyzing advanced concepts to help identify focused technology needs and their priorities.

Joyner, Claude R., II↗

DOE OSTI2020

Highly efficient separation membrane based on cellulose acetate/chitosan fibrous composite substrate with activated carbon functional adsorption layer

Abstract BACKGROUND For improving the permeability and selectivity of adsorption separation membranes, membrane materials, structural morphology and separation technology must continue to be investigated. Development of a membrane that is environmentally friendly, cost‐effective and with high filter precision is an important direction in current research. RESULTS The air pressure spraying method was used to prepare an activated carbon (AC)–cellulose acetate/chitosan (CA/CS) composite membrane. The CA/CS fiber composite membrane was prepared as substrate layer, and AC was loaded on the surface of the CA/CS composite membrane as a functional adsorption layer. When the spraying pressure was 0.01 MPa and the mass ratio of AC/CS was 2:1, a composite membrane with even and compact morphology could be obtained. Both the compact AC functional layer and complete CA/CS substrate layer endowed the AC–CA/CS composite membrane with an excellent water filtration property. At low feeding pressure, the permeate flux and rejection rate of bisphenol A (BPA) could reach 9.27 × 10 3 L m −2 h −1 and 98.31%, respectively. Meanwhile, the adsorption capacities of the membrane were investigated. It tended to equilibrate quickly in 2 min for dyes and BPA. The equilibrium adsorption capacities of the membrane for acid blue, acid yellow and BPA were 175.80, 164.0815 and 79.58 mg g −1 , respectively. The adsorption process conformed to pseudo‐second‐order kinetics and the Langmuir monolayer adsorption model. CONCLUSIONS This work could provide a practical and effective feasibility for membrane separation technology. © 2020 Society of Chemical Industry (SCI)

Zhao, Xiaoyan↗

DOE OSTI2020

Cybersecurity of Networked Microgrids: Challenges Potential Solutions and Future Directions

Networked microgrids are clusters of geographically-close, islanded microgrids that can function as a single, aggregate island. This flexibility enables customer-level resilience and reliability improvements during extreme event outages and also reduces utility costs during normal grid operations. To achieve this cohesive operation, microgrid controllers and external connections (including advanced communication protocols, protocol translators, and/or internet connection) are needed. However, these advancements also increase the vulnerability landscape of networked microgrids, and significant consequences could arise during networked operation, increasing cascading impact. To address these issues, this report seeks to understand the unique components, functions, and communications within networked microgrids and what cybersecurity solutions can be implemented and what solutions need to be developed. A literature review of microgrid cybersecurity research is provided and a gap analysis of what is additionally needed for securing networked microgrids is performed. Relevant cyber hygiene and best practices to implement are provided, as well as ideas on how cybersecurity can be integrated into networked microgrid design. Lastly, future directions of networked microgrid cybersecurity R&D are provided to inform next steps.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2022

DeePKS + ABACUS as a Bridge between Expensive Quantum Mechanical Models and Machine Learning Potentials

Recently, the development of machine learning (ML) potentials has made it possible to perform large-scale and long-time molecular simulations with the accuracy of quantum mechanical (QM) models. However, for different levels of QM methods, such as density functional theory (DFT) at the meta-GGA level and/or with exact exchange, quantum Monte Carlo, etc., generating a sufficient amount of data for training an ML potential has remained computationally challenging due to their high cost. In this work, we demonstrate that this issue can be largely alleviated with Deep Kohn–Sham (DeePKS), an ML-based DFT model. DeePKS employs a computationally efficient neural network-based functional model to construct a correction term added upon a cheap DFT model. Upon training, DeePKS offers closely matched energies and forces compared with high-level QM method, but the number of training data required is orders of magnitude less than that required for training a reliable ML potential. As such, DeePKS can serve as a bridge between expensive QM models and ML potentials: one can generate a decent amount of high-accuracy QM data to train a DeePKS model and then use the DeePKS model to label a much larger amount of configurations to train an ML potential. Further, this scheme for periodic systems is implemented in a DFT package ABACUS, which is open source and ready for use in various applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2022

NSRD-20, Functional Testing of Novel MTC HEPA Filtration Media

To improve the safety of Department of Energy (DOE) nuclear facilities, this project aimed to develop ceramic high efficiency particulate air (HEPA) filters that also create a low pressure-drop (dP) in use. The filters under consideration use mini-tubular ceramic (MTC) HEPA filtration media made with different architectures. Once successful, this project will reduce life-cycle costs, including safety basis, operational, and waste-disposal costs. The technology’s mini-tubular geometry is known to reduce dP when compared to flow through membranes of equivalent mass and surface area. Low dP facilitates retrofitting advanced filters into existing DOE facilities to make them safer while simultaneously reducing operational costs. Operations of ventilation systems are a key cost driver for DOE nuclear facilities; reducing dP can significantly reduce DOE’s operational costs. However, the filtration efficiency (FE) of this type of filtration media depends on the architecture of the filter media in an unknown way and requires testing. Functional testing of filtration media with different architectures will establish the performance of the filtration media and will enable development of guidance on design requirements to optimize filter performance.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Employing a Hardware-in-the-Loop Approach to Realize a Fully Homomorphic Controller for a Small Modular Advanced High Temperature Reactor

This paper addresses the cybersecurity challenges of advanced nuclear reactors by integrating fully homomorphic encryption (FHE) into their control systems, enabling encrypted processing of control signals without compromising functionality. Advanced nuclear reactors, including Small Modular Reactors (SMRs) and microreactors, aim to achieve autonomous and remote operations, reducing costs and enhancing competitiveness. However, these advancements expand the attack surface for cyberattacks, particularly in autonomous and remote operation scenarios. Cyberattacks can exploit vulnerabilities to manipulate physical processes, causing shutdowns, asset damage, or public harm. Such attacks begin with passive reconnaissance, where adversaries intercept communications or observe behaviors to gather information, which is then leveraged to execute cyber-physical attacks by injecting malicious commands. Nuclear power must adopt cybersecurity protection measures to secure the integrity and availability of their digital control systems. This paper demonstrates the application of FHE to secure operations by enabling encrypted processing of sensitive signals and parameters -- ensuring privacy without exposing data. FHE supports secure mathematical operations on encrypted data without requiring decryption. Using a hardware-in-the-loop (HIL) approach, this paper implements an FHE-integrated controller on a BeagleBone Black (BBB) controlling a simulation of the Small Modular Advanced High Temperature Reactor (SmAHTR). By doing so, the encrypted controller protects the integrity of critical set points and control signals during transmission and processing. Thus, FHE-integrated controllers enhance secure operations of advanced nuclear reactors while maintaining functionality.

control systems↗

DOE OSTI2024

High-throughput genetics enables identification of nutrient utilization and accessory energy metabolism genes in a model methanogen

Archaea are widespread in the environment and play fundamental roles in diverse ecosystems; however, characterization of their unique biology requires advanced tools. This is particularly challenging when characterizing gene function. Here, we generate randomly barcoded transposon libraries in the model methanogenic archaeon Methanococcus maripaludis and use high-throughput growth methods to conduct fitness assays (RB-TnSeq) across over 100 unique growth conditions. Using our approach, we identified new genes involved in nutrient utilization and response to oxidative stress. We identified novel genes for the usage of diverse nitrogen sources in M. maripaludis including a putative regulator of alanine deamination and molybdate transporters important for nitrogen fixation. Furthermore, leveraging the fitness data, we inferred that M. maripaludis can utilize additional nitrogen sources including $\tiny{L}$-glutamine, $\tiny{D}$-glucuronamide, and adenosine. Under autotrophic growth conditions, we identified a gene encoding a domain of unknown function (DUF166) that is important for fitness and hypothesize that it has an accessory role in carbon dioxide assimilation. Finally, comparing fitness costs of oxygen versus sulfite stress, we identified a previously uncharacterized class of dissimilatory sulfite reductase-like proteins (Dsr-LP; group IIId) that is important during growth in the presence of sulfite. When overexpressed, Dsr-LP conferred sulfite resistance and enabled use of sulfite as the sole sulfur source. The high-throughput approach employed here allowed for generation of a large-scale data set that can be used as a resource to further understand gene function and metabolism in the archaeal domain.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2022

Solid Oxide Cell Manufacturing Cost Tool

NETL has developed a detailed solid oxide cell (SOC) cost modeling tool. The tool provides a fully customizable spreadsheet that aids in cost estimation of large volume manufacturing of SOC (both fuel cell and electrolysis cell). The tool can be used to assist commercial developers and other end users to evaluate the costs of producing cells and stack components as SOC systems increase in scale. The manufacturing materials, labor, component costs, and specific equipment can be tailored to accurately reflect the desired manufacturing process. The tool is paired with a detailed user manual to assist in the understanding of the full functionality. This document is the spreadsheet tool. To access the associated user guide, please visit: <a href="https://netl.doe.gov/energy-analysis/details?id=f5823130-0d20-4a04-9c53-341682e58ac1" rel="noopener noreferrer">Energy Analysis | netl.doe.gov</a>

cost modeling↗

DOE OSTI2020

Cooperative Research and Development Agreement between National Energy Technology Laboratory and Birla Carbon U.S.A., Inc. [Abstract]

NETL researchers will be collaborating with Birla Carbon, U.S.A., Inc. (Birla Carbon) to leverage NETL's patented catalyst work on methane decomposition to commercialize an efficient and a cost-effective process for production of hydrogen and valuable carbon from natural gas. This catalytic methane decomposition is a promising technology, however, finding an appropriate catalyst to perform all the functions has been a challenge. NETL has developed a suitable catalyst for the process which has shown promising results. The heat required for this endothermic catalytic decomposition process is provided by combustion of a portion of the hydrogen. This process is cost effective, energy efficient, and environmentally friendly with minimal CO 2 mitigation costs. The objectives of the project include evaluation of the effect of feed gas composition on the performance, reduction of the catalyst production cost, and conduction of an in-depth large-scale cost analysis for a process suitable for applications at Birla Carbon.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

A light weight regularization for wave function parameter gradients in quantum Monte Carlo

The parameter derivative of the expectation value of the energy, ∂E/∂p, is a key ingredient in variational Monte Carlo (VMC) wave function optimization methods. In some cases, a naïve estimate of this derivative suffers from an infinite variance, which inhibits the efficiency of optimization methods that rely on a stable estimate of the derivative. In this work, we derive a simple regularization of the naïve estimator, which is trivial to implement in existing VMC codes, has finite variance, and a negligible bias, which can be extrapolated to zero bias with no extra cost. We use this estimator to construct an unbiased, finite variance estimation of ∂E/∂p for a multi-Slater–Jastrow trial wave function on the LiH molecule and in the optimization of a multi-Slater–Jastrow trial wave function on the CuO molecule. This regularized estimator is a simple and efficient estimator of ∂E/∂p for VMC optimization techniques.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Bayesian force fields from active learning for simulation of inter-dimensional transformation of stanene

Abstract We present a way to dramatically accelerate Gaussian process models for interatomic force fields based on many-body kernels by mapping both forces and uncertainties onto functions of low-dimensional features. This allows for automated active learning of models combining near-quantum accuracy, built-in uncertainty, and constant cost of evaluation that is comparable to classical analytical models, capable of simulating millions of atoms. Using this approach, we perform large-scale molecular dynamics simulations of the stability of the stanene monolayer. We discover an unusual phase transformation mechanism of 2D stanene, where ripples lead to nucleation of bilayer defects, densification into a disordered multilayer structure, followed by formation of bulk liquid at high temperature or nucleation and growth of the 3D bcc crystal at low temperature. The presented method opens possibilities for rapid development of fast accurate uncertainty-aware models for simulating long-time large-scale dynamics of complex materials.

Chemistry↗

DOE OSTI2025

Defect formation and microstructure tuning via proton irradiation to control electrochemical and phase reversibility in layered battery materials

The reversibility of phase transformation influences the functionality of electrode materials in batteries. In many battery materials, nanosized grains favor phase reversibility but at the cost of cyclability due to aggravated side reactions with the electrolyte. Here, in this study, we present a novel approach to enhance the phase transformation reversibility of layered oxide cathodes, exemplified by Na 2/3 Fe 1/2 Mn 1/2 O 2 through proton irradiation. In addition to forming defects, proton irradiation at sufficiently high doses can subdivide single grains into multiple nanodomains without physically rupturing them. Hence, the single grains of the material assume a pseudo-secondary particle nature without reducing the overall grain size. Preserving the grain size is advantageous, as it reduces side reactions, which is not possible with conventional grain size reduction methods. While chemical transformations and defect formation induced through proton irradiation can influence the stability of battery materials, it is expected that structural reorganization due to cycling-induced phase transformation will be contained within these nanodomains. Such confinement of phase transformation is potentially responsible for enhancing the reversibility of layered oxide materials in our study. Thus, our study suggests that grain subdivision could become an effective microstructure tuning strategy for managing electrochemical cycling-induced phase changes in battery electrodes.

25 ENERGY STORAGE↗

NASA NTRS2012

The Economics of NASA Mission Cost Reserves

Increases in NASA mission costs are well-noted but not well-understood, and there is little evidence that they are decreasing in frequency or amount over time. The need to control spending has led to analysis of the causes and magnitude of historical mission overruns, and many program control efforts are being implemented to attempt to prevent or mitigate the problem (NPR 7120). However, cost overruns have not abated, and while some direct causes of increased spending may be obvious (requirements creep, launch delays, directed changes, etc.), the underlying impetus to spend past the original budget may be more subtle. Gaining better insight into the causes of cost overruns will help NASA and its contracting organizations to avoid .them. This paper hypothesizes that one cause of NASA mission cost overruns is that the availability of reserves gives project team members an incentive to make decisions and behave in ways that increase costs. We theorize that the presence of reserves is a contributing factor to cost overruns because it causes organizations to use their funds less efficiently or to control spending less effectively. We draw a comparison to the insurance industry concept of moral hazard, the phenomenon that the presence of insurance causes insureds to have more frequent and higher insurance losses, and we attempt to apply actuarial techniques to quantifY the increase in the expected cost of a mission due to the availability of reserves. We create a theoretical model of reserve spending motivation by defining a variable ReserveSpending as a function of total reserves. This function has a positive slope; for every dollar of reserves available, there is a positive probability of spending it. Finally, the function should be concave down; the probability of spending each incremental dollar of reserves decreases progressively. We test the model against available NASA CADRe data by examining missions with reserve dollars initially available and testing whether they are more likely to spend those dollars, and whether larger levels of reserves lead to higher cost overruns. Finally, we address the question of how to prevent reserves from increasing mission spending without increasing cost risk to projects budgeted without any reserves. Is there a "sweet spot"? How can we derive the maximum benefit associated with risk reduction from reserves while minimizing the effects of reserve spending motivation?

Whitley, Sally↗