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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Dermatitis During Spaceflight Associated With HSV-1 Reactivation- A Case Study

Human alpha herpesviruses herpes simplex virus (HSV-1 or -2) and varicella zoster virus (VZV) establish latency in various cranial nerve ganglia, and often reactivate in response to stress-associated immune system dysregulation. Reactivation of Epstein Barr Virus (EBV), VZV, HSV-1 and Cytomegalovirus (CMV) is typically asymptomatic during spaceflight, though live/infectious virus has been recovered and the shedding rate increases with mission duration. The risk of clinical disease, therefore, may increase for astronauts assigned to extended missions (>180 days). Here, we report for the first time, a case of HSV-1 skin rash (dermatitis) occurring during a long duration spaceflight. The astronaut reported persistent dermatitis during flight, which was treated onboard with oral antihistamines and topical/oral steroids. No HSV-1 DNA was detected in 6-month pre-mission saliva samples, but on flight day 82, a saliva and rash swab both yielded 4.8 copies/ng DNA and 5.3×104 copies/ng DNA, respectively. Post-mission saliva samples continued to have high infectious HSV-1 load (1.67×107 copies/ng DNA). HSV-1 from both rash and saliva samples had 99.4% genotype homology. Additional physiological monitoring, including stress biomarkers (cortisol, dehydroepiandrosterone (DHEA), and salivary amylase), immune markers (adaptive regulatory and inflammatory plasma cytokines) and biochemical profile markers including vitamin/mineral status and bone metabolism are also presented for this case. These data highlight an atypical presentation of HSV-1 during spaceflight and underscore the importance of viral screening during clinical evaluations of in-flight dermatitis, to determine viral etiology and guide treatment.

Herpes, Viral Reactivation, Spaceflight, Dermatiti↗
NASA NTRSDate not supplied

Characterizing Wildfires in Western US.: A Cloud-based Case Study for Interdisciplinary Research using NASA Resources

This presentation will demonstrate a case study of interdisciplinary research done in the Amazon Web Services (AWS) cloud platform, in addition to in the local machine. We conduct data analysis next to data by leveraging various cloud-based data in NASA Earthdata Cloud, which are distributed by different missions/NASA Distributed Active Archive Centers (DAACs), and cloud computing resources at NASA. For instance, we directly access multiple datasets stored in the AWS Simple Storage Service (S3) buckets using a Python Jupyter notebook through a JupyterHub interface hosted in AWS (without having to download data), and conduct data analysis next to data in the cloud. We will also show how to share the research results following Open Source policy. This case study characterizes the change in wildfire events in the western United States during the past 20 years. In particular, we focus on the wildfires in California in 2021, one of the most severe wildfire years occurring in the most recent 20 years in California. We will analyze the possible causes of wildfires, such as drought conditions and climate variability, and examine the impacts of wildfires on air quality and atmospheric composition, and on land cover. We will examine the data distributed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), including aerosols and meteorological data from the NASA Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), precipitation from the Global Precipitation Measurement (GPM) and Global Precipitation Climate Project (GPCP), and aerosol index from Ozone Monitoring Instrument (OMI). We also utilize the data distributed by the Physical Oceanography (PO) DAAC, such as Sea Surface Temperature (SST) data from the Group for High Resolution Sea Surface Temperature (GHRSST), and the data distributed by Land Processes (LP) DAAC, such as Normalized Difference Vegetation Index (NDVI).

Xiaohua Pan↗
NASA NTRS2023

A Blockchain Case Study for Urban Air Mobility Operational Intent

To realize the potential of Urban Air Mobility (UAM), an assurance of cybersecurity is critical for public acceptance. UAM is a concept that proposes to develop short-range, point-to-point transportation systems in metropolitan areas using vertical takeoff and landing (VTOL) aircraft to overcome increasing surface congestion. The growth in the development of UAM systems, and the associated data exchange and service interactions will be at risk due to numerous types of cybersecurity attacks. The intent of this work is to leverage a permissioned blockchain to simulate secure data exchange and storage for the UAM operational intent use case. In this case study, two vehicle operators are operating in the same airspace. Their intent is to fly vehicles that land at a shared vertiport, securely.

Urban Air Mobility↗
NASA NTRSDate not supplied

Summary of the 6th AIAA Propulsion Aerodynamics Workshop Nozzle Test Case: Heated Supersonic Axisymmetric Jets

This paper summarizes findings from the sixth AIAA Propulsion Aerodynamics Workshop (PAW) nozzle test case. The focus of the workshop participants was turbulent supersonic round jets with variation in jet Mach number and jet heating. Three nozzles were utilized with on-design jet Mach numbers of 1.36, 1.63, and 2.00. A heated jet for each of these three nozzles at on-design conditions, a temperature matched on-design condition at Mach 1.63, and an off-design heated condition for the Mach 1.63 nozzle were the five cases examined. Workshop participants utilized Reynolds-averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) based techniques. Computational fluid dynamics (CFD) solutions were compared with non-intrusive measurements of velocities and temperatures, including both mean values and turbulence statistics. In general, the RANS approaches were unable to capture the trend of reduced mixing as the jet Mach number increased. Incorporation of compressibility corrections improved the agreement with experimental measurements in terms of trends with varying jet Mach number, but also increased the jet potential core lengths to be in worse agreement with data. RANS methods were able to reasonably capture trends of jet heating. The LES-based approaches as a whole were able to capture the effects of compressibility more accurately. Effects of jet heating were captured well by LES. None of the LES approaches introduced disturbances from the wall boundary layers of the nozzle into the jet mixing layer, which would affect the jet flow physics modeling in the initial part of the jet shear layer, but would be very computationally demanding.

supersonic jet↗
NASA NTRS2024

Expansion of Check-Cases for 6DOF Simulation

This effort expands upon a previous NASA activity that developed flight simulation benchmark check-cases to include new check-cases for the Cislunar domain, comparing multiple NASA simulation tools. The results of this effort describe the benefits of standardizing inputs, simulation comparisons and describe an interactive website that enables comparison of externally provided simulation data. Participating simulations improved their software and identified implementation errors. This activity elevated simulation credibility and provided a measure of validation for the simulations actively in use for NASA’s Human Landing Systems (HLS).

Modeling↗
NASA NTRSDate not supplied

WMLES for the Fifth High-Lift PredictionWorkshop Cases Using FUN3D

This paper presents solution assessments and grid convergence studies for the test cases outlined in the Fifth High-Lift Prediction Workshop (HLPW-5), focusing on the high-lift Common Research Models (CRM-HL). The study utilizes a wall-modeled large-eddy simulation (WMLES) methodology developed in the unstructured-grid, node-centered flow solver FUN3D. The second-order accurate simulations conducted in this study utilize a finite-volume spatial discretization and an implicit temporal scheme. Large-scale turbulent features are resolved away from the wall, with small-scale effects captured by the Vreman subgrid-scale model. An equilibrium wall function uses the first grid point off the wall serving as the critical interface between the wall model and the large-eddy simulation region, thus requiring careful placement in grid design. WMLES solutions are assessed for HLPW-5 cases, including a clean wing-body configuration and geometry-buildup configurations corresponding to the 5.1\% ONERA CRM-HL model. Grid-convergence studies are systematically conducted using uniformly refined grids. Moreover, simulation results and grid sensitivity are presented for the NASA 5.2\% CRM-HL configuration at both moderate and flight-scale Reynolds numbers. Overall, WMLES results are satisfactory and agree well with available experimental data, especially on sufficiently fine grids.

high-lift aerodynamics↗
NASA NTRS2025

An Observation-Driven Framework for Modeling Post-Fire Hydrologic Response: Evaluation for Two Central California Case Studies

In a warming climate, wildfires are becoming increasingly common, especially in semi-arid environments. Wildfires can disrupt forest ecosystems and induce changes to the land surface. Collectively, these impacts can alter the hydrologic response of a catchment following a fire, resulting in increased potential for surface runoff, reduced evapotranspiration, and, ultimately, a higher risk for flash flooding and mass wasting. The timescale of post-fire recovery of hydrological processes to return to pre-fire conditions is not well established due to the lack of ground measurements. Accurate characterization of the impacts of fire on hydrologic response is also challenging to simulate, given the complex interplay of various processes. Here, we present a generalized framework to quantify the impacts of wildfire on runoff generation. We consider the disturbances in the vegetation and soil as the two main factors contributing to post-fire floods. Using an ensemble modeling structure to account for parameter uncertainty, remotely sensed leaf area index (LAI) is assimilated into a land surface model (LSM) to simulate vegetation disturbance, and the maximum land surface saturation LSM parameter is decreased to parameterize the soil disturbance following observed fires. We consider the impacts of fire-induced changes to LAI and soil saturation on hydrologic states like runoff and evapotranspiration for two case studies. These case studies demonstrate the general applicability of hydrophobicity formulation to serve as a guideline for exploring the range of hydrologic responses post-fire.

Fire Hydrology↗
NASA NTRSDate not supplied

Subscale Hardware-In-The-Loop Results for Hybrid Electric Turbofan Controls Use Cases

NASA is investigating hybrid electric turbine engine systems for commercial transport aircraft due to the potentially significant improvements hybrid electric technology offers in performance, fuel consumption, and operational and design flexibility. Recently, the technology has been tested at full scale in partnership with industry and advanced to Technology Readiness Level 4. This presentation will focus on a recent subscale hardware-in-the-loop test of an open source turbofan engine model developed by NASA. The Advanced Geared Turbofan 30,000 lbf – electrified (AGTF30-e) engine is used as a reference model to demonstrate control system design and use cases for an example mild hybrid electric system with no large-scale energy storage. This model is run in real-time in NASA’s Hybrid Propulsion Emulation Rig (HyPER) and is used to drive an emulation of the turbomachinery system using subscale electric machines. This dynamic scaled shaft emulation interacts with a subscale (<100 kW) hybrid system consisting of electric machines, motor controllers, and a programmable electronic load. Specific use cases demonstrated include the use of Turbine Electrified Energy Management to improve operation during transients, megawatt-scale power extraction from the AGTF30-e, and power transfer between engine spools. Results related to the effectiveness of hybrid systems are qualitatively compared to results from industry testing.

Hybrid↗
NASA NTRSDate not supplied

Overarching Properties as Means of Compliance: An Industrial Case Study

The Overarching Properties (OPs) have been created by an inter-national working group and are being evaluated by the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), industry, and other certifying agencies in an effort to streamline certification processes. Their intent is to facilitate the use of alternative approaches and to al-low flexibility to combine the system, software, and complex hardware certification. The hope is that the FAA may eventually establish an Advisory Circular that offers the OPs as a Means of Compliance (MoC) for software approval (and eventually systems and hardware) by showing the product possesses the three OPs: Intent (specification of the intended behavior), Correctness (implementation of the intended behavior) and Innocuity (safety of unintended behavior). In the certification community, there is still a concern about the practicability of using such high level properties in certification. This paper aims to address that concern by showing possession of the OPs in an industrial case study using assurance arguments. The two main contributions of this paper are: a certification process based on OPs as Means of Compliance, and a certification argument for an on-board physical model of an UAV, as industrial example. We pro-pose a hybrid approach for the certification process that combines OPs with existing certification standards. Thus, OPs can be used for parts of a system that uses technologies that are not supported by current standards or for which existing standards require additional effort without commensurate additional safety assurance.

certification↗
NASA NTRS2004

Postflight balance control recovery in an elderly astronaut: a case report

OBJECTIVE: To examine the sensorimotor adaptive response of a 77-year-old man exposed to the gravito-inertial challenges of orbital space flight. STUDY DESIGN: Prospective case study with retrospective comparisons. SETTING: NASA Neurosciences Laboratory (Johnson Space Center) and Baseline Data Collection Facility (Kennedy Space Center). PRIMARY PARTICIPANT: One 77-year-old male shuttle astronaut. INTERVENTION: Insertion into low Earth orbit was used to remove gravitational stimuli and thereby trigger sensorimotor adaptation to the microgravity environment. Graviceptor stimulation was reintroduced at landing, and sensorimotor readaptation to the terrestrial environment was tracked to completion. MAIN OUTCOME MEASURES: Computerized dynamic posturography tests were administered before and after orbital flight to determine the magnitude and time course of recovery. RESULTS: The elderly astronaut exhibited balance control performance decrements on landing day; however, there were no significant differences between his performance and that of younger astronauts tested on the same shuttle mission or on previous shuttle missions of similar duration. CONCLUSIONS: These results demonstrate that the physiological changes attributed to aging do not necessarily impair adaptive sensorimotor control processes.

Case Reports↗
NASA NTRS2006

CCSDS SLE Service Management: Real-World Use Cases

The purpose of this paper is to illustrate how the standard SLE-SM services can be applied to the operations of current TT&C providers. It begins with a brief overview of the scope and operating environment of the SLE-SM services, then describes several use cases in which SLE-SM services can be applied to existing operational situations. The paper also addresses how SLE-SM services can be adopted in an evolutionary fashion. The paper concludes with a brief identification of additions to SLE-SM that are under consideration to make SLE-SM applicable to an even broader range of network operations concepts, policies, and procedures.

Consultative Committee for Space Data Systems (CCS↗
NASA NTRS2003

The Power of a Question: A Case Study of Two Organizational Knowledge Capture Systems

This document represents a presentation regarding organizational knowledge capture systems which was delivered at the HICSS-36 conference held from January 6-9, 2003. An exploratory case study of two knowledge resources is offered. Then, two organizational knowledge capture systems are briefly described: knowledge transfer from practitioner and the use of questions to represent knowledge. Finally, the creation of a database of peer review questions is suggested as a method of promoting organizational discussions and knowledge representation and exchange.

case study↗
NASA NTRS2015

Dynamic Safety Cases for Through-Life Safety Assurance

We describe dynamic safety cases, a novel operationalization of the concept of through-life safety assurance, whose goal is to enable proactive safety management. Using an example from the aviation systems domain, we motivate our approach, its underlying principles, and a lifecycle. We then identify the key elements required to move towards a formalization of the associated framework.

Dynamic Safety Case↗
NASA NTRSDate not supplied

UTM Concepts and Use Cases

The presentation provides an overview of the UTM Research Transition Team (RTT) and the role of the Concepts and Use Cases Working Group (CWG) as part of the joint NASA-FAA effort. The deliverables, role in tests/demonstrations, future work, and summary impact of the CWG are the main areas covered.

UTM↗
NASA NTRSDate not supplied

FUN3D Mesh Adaptation Simulations of 4th AIAA High-Lift Prediction Workshop Case 1a

Special sessions of the High Lift Prediction/Geometry & Mesh Generation Workshop. Will be written and presented at AIAA Aviation 2022. Describes in detail FUN3D Mesh adaptation simulation results for the 4th AIAA High-Lift Prediction Workshop. RANS (Stabilized Finite Element SA-neg) results for Case 1a are presented.

4th High-Lift Prediction Workshop Case 1a↗