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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 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

TPSAS-NF1676L-21094-DND

Advanced knowledge in atmospheric CO 2 distributions is critical in predicting the Earth's future climate. Large uncertainties in the prediction persist due to limited observations. This study focuses on the development and demonstration of the Intensity-Modulated Continuous-Wave (IM-CW) lidar for atmospheric CO 2 measurements. Simulations show that IM-CW lidar systems operating at 1.57 um will provide precise atmospheric column CO 2 measurements from space. Airborne systems have demonstrated the feasibility of the technology and instrumentation for space active atmospheric CO 2 missions. In this presentation, the atmospheric CO 2 column measurements from airborne flight campaigns and lidar system simulations for space missions will be discussed. Data analysis shows that airborne lidar CO 2 column measurements over desert and vegetated surfaces agree well with in-situ measurements. A measurement precision of 0.08% or ~0.3 ppmv for a 10-s average over these surfaces has also been achieved. Generally, airborne flight campaigns have demonstrated that the column CO 2 measurements of the current IM-CW lidar systems meet the accuracy and precision requirements of atmospheric CO 2 measurements. Furthermore, analyses of space CO 2 measurements shows that the current IM-CW lidar technology and approach will enable space missions to achieve their science goals.

Bing Lin↗
NASA NTRS1967

Star/horizon simulator used to test space guidance system

Star/horizon simulator is used for alignment and optical plus photoelectric tests of the sextant for the Apollo guidance and navigation system optical unit assembly. The unit is basically a refractive collimator with a two inch objective lens system and a twenty-four inch focal length.

Schmidt, W. C.↗
DOE OSTI2020

PRIME: a real-time cyber-physical systems testbed: from wide-area monitoring, protection, and control prototyping to operator training and beyond

As the power grid continues to evolve with advanced wide-area monitoring, protection, and control (WAMPAC) algorithms, there is an increasing need for realistic testbed environments with industry-grade software and hardware-in-the-loop (HIL) to perform verification and validation studies. Such testbed environments serve as ideal platforms to perform WAMPAC prototyping, operator training, and also to study the impacts of different types of cyberattack scenarios on the operation of the grid. In this paper, we introduce PRIME (PNNL cybeR physIcal systeMs tEstbed): the testbed that integrates real-time transmission system simulator with commercial industry grade energy management system (EMS) software and remote hardware-in-the-loop (RHIL). PRIME is an end-to-end, modular testbed that allows high-fidelity RHIL experimentation of a power system. We present two detailed case studies (fault location and clearing in transmission system, and operator training) to showcase the capabilities of our PRIME testbed. Finally, we briefly discuss some of the potential limitations of our testbed in terms of scalability and flexibility to setup larger test systems and identify directions for future work to address those limitations.

42 ENGINEERING↗
DOE OSTI2025

Spatial Impacts of Electric Vehicle Charging on Power Grid Stability: A Downtown Atlanta Case Study

The rapid increase in electric vehicle (EV) charging demand poses a potential risk to power grid stability, particularly as the spatial distribution of this demand remains underexplored. Existing research often focuses on technical optimization models while overlooking the geographic and human dynamics that affect energy consumption. This study addresses this gap by incorporating mobility data to estimate both building energy use and EV charging demand while also considering geographic factors for a better understanding of grid load. Using agent-based simulations and the Open-Source Distribution System Simulator, the study evaluates the effect of various EV penetration scenarios on grid voltage and unbalance. The results show that, although voltage remains within acceptable limits at lower EV penetration rates, significant voltage drop and unbalance occur as EV penetration exceeds 40%, particularly in residential areas with high charging demand. This study offers a framework for integrating spatial analysis and mobility data in power network simulations, providing insights for future EV infrastructure planning.

Pan, Melrose [ORNL] (ORCID:000000031627448X)↗
NASA NTRS1972

Shuttle sortie simulation using a Lear jet aircraft: Mission no. 1 (assess program)

The shuttle sortie simulation mission of the Airborne Science/Shuttle Experiments System Simulation Program which was conducted using the CV-990 aircraft is reported. The seven flight, five day mission obtained data on experiment preparation, type of experiment components, operation and maintenance, data acquisition, crew functions, timelines and interfaces, use of support equipment and spare parts, power consumption, work cycles, influence of constraints, and schedule impacts. This report describes the experiment, the facilities, the operation, and the results analyzed from the standpoint of their possible use in aiding the planning for experiments in the Shuttle Sortie Laboratory.

Mulholland, D. R.↗
NASA NTRS1987

System architecture for telerobotic servicing and assembly tasks

The architecture of an integrated telerobotics laboratory which is being used for research on the mechanisms, controls, sensing, and operator interface required to accomplish space telerobotic tasks is described. The laboratory hardware is considered, including manipulator and controller, end effector, and vision. The virtual architecture, a common reference model for most of the laboratory applications, is discussed. Teleoperator and robotics system simulations which have been performed using the system are discussed.

Harrison, F. Wallace, Jr.↗
NASA NTRS1990

Gamma Ray Observatory (GRO) dynamics simulator requirements and mathematical specifications, revision 1

The requirements and mathematical specifications for the Gamma Ray Observatory (GRO) Dynamics Simulator are presented. The complete simulator system, which consists of the profie subsystem, simulation control and input/output subsystem, truth model subsystem, onboard computer model subsystem, and postprocessor, is described. The simulator will be used to evaluate and test the attitude determination and control models to be used on board GRO under conditions that simulate the expected in-flight environment.

Harman, R.↗
NASA NTRS1991

Berthing simulator for space station and orbiter

The development of a real-time man-in-the-loop berthing simulator is in progress at NASA Lyndon B. Johnson Space Center (JSC) to conduct a parametric study and to measure forces during contact conditions of the actual docking mechanisms for the Space Station Freedom and the orbiter. In berthing, the docking ports of the Space Station and the orbiter are brought together using the orbiter robotic arm to control the relative motion of the vehicles. The berthing simulator consists of a dynamics docking test system (DDTS), computer system, simulator software, and workstations. In the DDTS, the Space Station, and the orbiter docking mechanisms are mounted on a six-degree-of-freedom (6 DOF) table and a fixed platform above the table. Six load cells are used on the fixed platform to measure forces during contact conditions of the docking mechanisms. Two Encore Concept 32/9780 computers are used to simulate the orbiter robotic arm and to operate the berthing simulator. A systematic procedure for a real-time dynamic initialization is being developed to synchronize the Space Station docking port trajectory with the 6 DOF table movement. The berthing test can be conducted manually or automatically and can be extended for any two orbiting vehicles using a simulated robotic arm. The real-time operation of the berthing simulator is briefly described.

Veerasamy, Sam↗
NASA NTRS1994

The analysis of a generic air-to-air missile simulation model

A generic missile model was developed to evaluate the benefits of using a dynamic missile fly-out simulation system versus a static missile launch envelope system for air-to-air combat simulation. This paper examines the performance of a launch envelope model and a missile fly-out model. The launch envelope model bases its probability of killing the target aircraft on the target aircraft's position at the launch time of the weapon. The benefits gained from a launch envelope model are the simplicity of implementation and the minimal computational overhead required. A missile fly-out model takes into account the physical characteristics of the missile as it simulates the guidance, propulsion, and movement of the missile. The missile's probability of kill is based on the missile miss distance (or the minimum distance between the missile and the target aircraft). The problems associated with this method of modeling are a larger computational overhead, the additional complexity required to determine the missile miss distance, and the additional complexity of determining the reason(s) the missile missed the target. This paper evaluates the two methods and compares the results of running each method on a comprehensive set of test conditions.

Kaplan, Joseph A.↗
NASA NTRS2003

The Development of Design Tools for Fault Tolerant Quantum Dot Cellular Automata Based Logic

We are developing software to explore the fault tolerance of quantum dot cellular automata gate architectures in the presence of manufacturing variations and device defects. The Topology Optimization Methodology using Applied Statistics (TOMAS) framework extends the capabilities of the A Quantum Interconnected Network Array Simulator (AQUINAS) by adding front-end and back-end software and creating an environment that integrates all of these components. The front-end tools establish all simulation parameters, configure the simulation system, automate the Monte Carlo generation of simulation files, and execute the simulation of these files. The back-end tools perform automated data parsing, statistical analysis and report generation.

Armstrong, Curtis D.↗
NASA NTRS2012

Impact of Non-Uniform Beam Filling on Spaceborne Cloud and Precipitation Radar Retrieval Algorithms

In this presentation we will discuss the performance of classification and retrieval algorithms for spaceborne cloud and precipitation radars such as the Global Precipitation Measurement mission Dual-frequency Precipitation Radar (GPM/DPR), and notional radar for the Aerosol/Clouds/Ecosystem (ACE) mission and related concepts. Spaceborne radar measurements are simulated either from Airborne Precipitation Radar 2nd Generation observations, or from atmospheric model outputs via instrument simulators contained in the NASA Earth Observing Systems Simulators Suite (NEOS(sup 3)). Both methods account for the three dimensional nature of the scattering field at resolutions smaller than that of the spaceborne radar under consideration. We will focus on the impact of non-homogeneities of the field of hydrometeors within the beam. We will discuss also the performance of methods to identify and mitigate such conditions, and the resulting improvements in retrieval accuracy. The classification and retrieval algorithms analyzed in this study are those derived from APR-2's Suite of Processing and Retrieval Algorithms (ASPRA); here generalized to operate on an arbitrary set of radar configuration parameters to study the expected performance of spaceborne cloud and precipitation radars. The presentation will highlight which findings extend to other algorithm families and which ones do not.

Aerosol/Clouds/Ecosystem (ACE)↗
NASA NTRS1990

Performance measurements for a laboratory-simulated 30/20 GHz communication satellite transponder

NASA has developed a digital satellite communications system simulator and test bed facility, known as the Systems Integration, Test and Evaluation (SITE) Project. The purpose of the facility is to evaluate satellite system components, develop and verify system concepts, and perform satellite system experiments. A recently completed set of experiments measured the performance of the 30/20 GHz satellite transponder portion of the system in terms of RF parameters and high rate digital data transmission. The results of these tests indicate the quality of data transmission which can be obtained under various transponder conditions, as well as the relative effects of degraded RF performance on the bit-error rate (BER) of transmitted data.

Kerczewski, Robert J.↗
NASA NTRS1981

The role of the research simulator in the systems development of rotorcraft

The potential application of the research simulator to future rotorcraft systems design, development, product improvement evaluations, and safety analysis is examined. Current simulation capabilities for fixed-wing aircraft are reviewed and the requirements of a rotorcraft simulator are defined. The visual system components, vertical motion simulator, cab, and computation system for a research simulator under development are described.

Statler, I. C.↗
NASA NTRS1987

FLUINT - General fluid system analysis with SINDA '85

This paper introduces FLUINT (FLUid INTegrator), a general fluid system simulation program that works in conjunction with SINDA '85 (Systems Improved Numerical Differencing Analyzer, 1985 version). FLUINT solves arbitrary networks representing internal fluid systems while SINDA '85 simultaneously solves traditional thermal networks. This transportable program is intended to provide spacecraft thermal management engineers with the analytic tools needed to simulate single- and two-phase coolant loops. The fundamental concepts for fluid system modeling are described, and methods of modeling complex, hardware-specific components are outlined. Underlying correlations and solution methods are briefly discussed. Example analyses and comparisons to test data are provided.

Cullimore, B. A.↗
NASA NTRS1990

Expert system for scheduling simulation lab sessions

Implementation and results of an expert system used for scheduling session requests for the Systems Engineering Simulator (SES) laboratory at the NASA Johnson Space Center (JSC) are discussed. Weekly session requests are received from astronaut crew trainers, procedures developers, engineering assessment personnel, software developers, and various others who wish to access the computers, scene generators, and other simulation equipment available to them in the SES lab. The expert system under discussion is comprised of a data acquisition portion - two Pascal programs run on a personal computer - and a CLIPS program installed on a minicomputer. A brief introduction to the SES lab and its scheduling background is given. A general overview of the system is provided, followed by a detailed description of the constraint-reduction process and of the scheduler itself. Results from a ten-week trial period using this approach are discussed. Finally, a summary of the expert system's strengths and shortcomings are provided.

Lund, Chet↗
NASA NTRS1990

Performance measurements for a laboratory-simulated 30/20 GHz communication satellite transponder

NASA has developed a digital satellite communications system simulator and test bed facility, known as the SITE (System Integratrion, Test and Evaluation) Project. The purpose of the facility is to evaluate satellite system components, develop and verify system concepts, and perform satellite system experiments. A recently completed set of experiments measured the performance of the 30/20 GHz satellite transponder portion of the system in terms of RF parameters and high rate digital data transmission. The results of these tests indicate the quality of data transmission which can be obtained under various transponder operating conditions, as well as the relative effects of degraded RF performance on the bit-error rate (BER) of transmitted data.

Kerczewski, Robert J.↗