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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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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

SUbsonic Single Aft eNgine (SUSAN) Electrofan: An Advanced Hybrid Electric Concept for Future Single-Aisle Aircraft

Address the aviation industry’s goal of achieving net-zero carbon emissions by 2050. Design an aircraft concept that can significantly reduce fuel burn and emissions in large regional transport aircraft carrying up to 180 passengers. Retain speed, size, and range in current commercial aircraft and utilize existing airport infrastructure and airspace management systems. Reduce operating costs while improving safety and efficiency.

Electrified Aircraft Propulsion (EAP)↗
NASA NTRS2021

Reliability and Safety Assessment of Urban Air Mobility Concept Vehicles

The following work was commissioned by the National Aeronautics and Space Administration (NASA) to guide industry and future regulation related to urban air mobility (UAM). Prior studies compared the relative safety of NASA concept vehicles, Figure ES1, designed for UAM and provided recommendations for industry research, aircraft architectural improvements, and regulatory updates. After the prior study completed, the European Aviation Safety Agency (EASA) released regulatory guidance in the form of a special condition (SC), SC-VTOL-01, for multirotors with distributed propulsion and flight controls (DPFC). The objective of the current work was to develop DPFC architectures that will comply with SC-VTOL-01. Vehicle designs, DPFC architectures, and stability & control (S&C) models were developed to find limitations and trends to guide industry. To guide this task, NASA developed quad, hex, and an octorotor to better define vehicle attributes and trade space. Aircraft for study included electric, hybrid-electric, and turboshaft powerplants and collective and RPM control schemes. Assessments are in terms of the safety level achieved, and/or aircraft component/features needed to meet SC-VTOL-01. The most challenging criteria being the catastrophic failure rate, ≤10-9 catastrophic failures per flight hour, and that no single failures may result in a catastrophic event. A disciplined process was followed, similar to that in Aerospace Recommended Practice (ARP) 4761. A preliminary system safety assessment (PSSA) leveraged prior work as a basis of creating failure rate budgets for system design teams. System designs were updated and iterated upon, working with reliability and safety subject matter experts to develop SC-VTOL-01 compliant designs. Design changes were reflected in updated PSSAs for initial verification of compliance. The DPFC architecture was broken into four system design teams, the (1) flight control system (FCS), (2) drive and power system, (3) thermal management system (TMS), and (4) electrical power and distribution system. The FCS including elements necessary to control the aircraft, drive and power including elements necessary to generate and transmit shaft power, the TMS including elements necessary to maintain temperature limits in all operating environments, and electrical pow-er and distribution including equipment necessary to store and transmit electrical energy. Results found that all aircraft evaluated may have paths to comply with SC-VTOL-01, Figure ES2. However, S&C models showed large power transients that must be addressed and PSSA results show that future work is needed in single load path structures, high voltage power storage and distribution, and in motor/rotor overspeed protection.

Boeing↗
NASA NTRS2024

SUbsonic Single Aft eNgine (SUSAN) Power/Propulsion System Control Architecture Updates

The development of hybrid-electric propulsion technology for commercial transport aircraft presents opportunities for new designs that can reduce fuel consumption and greenhouse gas emissions and improve safety and reliability compared to modern aircraft. The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a conceptual design for a transport aircraft with a series/parallel partial hybrid-electric propulsion system being developed by NASA as a reference design for a regional transport aircraft with a high degree of electrification. The SUSAN concept incorporates multiple tightly coupled power, propulsion, and flight control systems that introduce new challenges to the control design process, requiring a hierarchical and more coordinated control approach. This report summarizes updates to the SUSAN power/propulsion system (PPS) model and control architecture made in preparation for planned flight simulator and hardware-in-the-loop testing at the NASA Glenn Research Center. These updates include a new electrical power system model developed using the NASA-developed Electrical Modeling and Thermal Analysis Toolbox (EMTAT) and a new PPS control architecture that improves the operational flexibility and responsiveness of the propulsion system. The performance of the updated controller is demonstrated and discussed.

SUSAN↗
NASA NTRS2023

Assessment of Electrical, Electronic, and Electromechanical (EEE) Parts Copper Wire Bonds for Space Programs

The NASA Electronic Parts and Packaging Program co-manager, requested the NASA Engineering and Safety Center (NESC) to compile a body of publicly available knowledge on copper (Cu) wire bonds and perform reliability testing and analysis on these bonds, including environment tests, sample destructive physical analysis, and bond pull/shear tests during environment test intervals. The goal was to understand the risks of using Cu wire bonds for space applications and develop guidelines on Cu bond pull/shear limits for NASA applications. This document contains the results of the NESC assessment.

Electrical, Electronic, and Electromechanical↗
NASA NTRSDate not supplied

Application of System-Theoretic Process Analysis (STPA) to a NASA Concept Electric Aircraft Battery System

System-Theoretic Process Analysis (STPA) is a systems-based hazard analysis method that identifies unsafe interactions and control deficiencies in complex systems but has been rarely used for NASA programs in favor of more well-established hazard analyses. To evaluate its applicability, a NASA Safety and Mission Assurance (SMA) team applied the STPA method to an early-stage hybrid electrified aircraft concept, focusing on the energy storage system and electric powertrain. Objectives include assessing STPA’s value relative to traditional methods and its suitability for early design phases. Activities include team training, system review, detailed STPA execution, and comparison with traditional analyses. Findings show STPA provides a structured, comprehensive hazard evaluation and can identify additional risks by expanding analysis boundaries. However, traditional methods can yield similar results when applied rigorously, though they typically require more mature designs. Overall, STPA is a valuable addition, particularly for early development, informing safety requirements and supporting preliminary hazard analyses. Further pilot applications are recommended.

Electric Aviation↗
NASA NTRS1977

A study of selected environmental quality remote sensors for free flyer missions launched from the space shuttle

The sensors were examined for adaptability to shuttle by reviewing pertinent information regarding sensor characteristics as they related to the shuttle and Multimission Modular Spacecraft environments. This included physical and electrical characteristics, data output and command requirements, attitude and orientation requirements, thermal and safety requirements, and adaptability and modification for space. The sensor requirements and characteristics were compared with the corresponding shuttle and Multimission Modular Spacecraft characteristics and capabilities. On this basis the adaptability and necessary modifications for each sensor were determined. A number of the sensors were examined in more detail and estimated cost for the modifications was provided.

Goldstein, H. W.↗
NASA NTRS1991

Failure analysis of the lithium battery: A study of the header deposit on the cell top and diffusion within the electrode glass seal using nuclear microanalysis and FFTIR spectroscopy

The Solid Rocket Booster Range Safety System (SRBRSS) uses a lithium/poly-carbon monofluoride primary battery as a source of electrical power. After cell fabrication and activation, some battery cells have shown self discharge. One possible source of this cell discharge has been suggested to be the formation and growth of a conducting crystallized chemical compound across the glass bead insulator, electrically shorting the glass bead to the casing. This laboratory has begun an analysis of this compound, the glass seal holding the cathode into place, and the cell electrolyte, using Fast Fourier Transform Infrared (FFTIR) Analysis, Rutherford Backscattering Spectroscopy (RBS), and Nuclear Reaction Microanalysis. Preliminary measurements have confirmed the existence of lithium, nitrogen, fluorine, and oxygen on a reddish-brown deposit covering parts of the glass seal holding the positive electrode in place. Cells using Li metal electrodes, have many advantages over conventional primary batteries. One principal disadvantage of using Li batteries on a commercial basis would be the environmental impact of the fluorocarbon material. Another would be the relatively high expense of (CF)n.

Hassan, Razi A.↗
NASA NTRS1997

Speed Sensorless Induction Motor Drives for Electrical Actuators: Schemes, Trends and Tradeoffs

For a decade, induction motor drive-based electrical actuators have been under investigation as potential replacement for the conventional hydraulic and pneumatic actuators in aircraft. Advantages of electric actuator include lower weight and size, reduced maintenance and operating costs, improved safety due to the elimination of hazardous fluids and high pressure hydraulic and pneumatic actuators, and increased efficiency. Recently, the emphasis of research on induction motor drives has been on sensorless vector control which eliminates flux and speed sensors mounted on the motor. Also, the development of effective speed and flux estimators has allowed good rotor flux-oriented (RFO) performance at all speeds except those close to zero. Sensorless control has improved the motor performance, compared to the Volts/Hertz (or constant flux) controls. This report evaluates documented schemes for speed sensorless drives, and discusses the trends and tradeoffs involved in selecting a particular scheme. These schemes combine the attributes of the direct and indirect field-oriented control (FOC) or use model adaptive reference systems (MRAS) with a speed-dependent current model for flux estimation which tracks the voltage model-based flux estimator. Many factors are important in comparing the effectiveness of a speed sensorless scheme. Among them are the wide speed range capability, motor parameter insensitivity and noise reduction. Although a number of schemes have been proposed for solving the speed estimation, zero-speed FOC with robustness against parameter variations still remains an area of research for speed sensorless control.

Elbuluk, Malik E.↗
NASA NTRS2005

Pre-Launch GOES-R Risk Reduction Activities for the Geostationary Lightning Mapper

The GOES-R Geostationary Lightning Mapper (GLM) is a new instrument planned for GOES-R that will greatly improve storm hazard nowcasting and increase warning lead time day and night. Daytime detection of lightning is a particularly significant technological advance given the fact that the solar illuminated cloud-top signal can exceed the intensity of the lightning signal by a factor of one hundred. Our approach is detailed across three broad themes which include: Data Processing Algorithm Readiness, Forecast Applications, and Radiance Data Mining. These themes address how the data will be processed and distributed, and the algorithms and models for developing, producing, and using the data products. These pre-launch risk reduction activities will accelerate the operational and research use of the GLM data once GOES-R begins on-orbit operations. The GLM will provide unprecedented capabilities for tracking thunderstorms and earlier warning of impending severe and hazardous weather threats. By providing direct information on lightning initiation, propagation, extent, and rate, the GLM will also capture the updraft dynamics and life cycle of convective storms, as well as internal ice precipitation processes. The GLM provides information directly from the heart of the thunderstorm as opposed to cloud-top only. Nowcasting applications enabled by the GLM data will expedite the warning and response time of emergency management systems, improve the dispatch of electric power utility repair crews, and improve airline routing around thunderstorms thereby improving safety and efficiency, saving fuel and reducing delays. The use of GLM data will assist the Bureau of Land Management (BLM) and the Forest Service in quickly detecting lightning ground strikes that have a high probability of causing fires. Finally, GLM data will help assess the role of thunderstorms and deep convection in global climate, and will improve regional air quality and global chemistry/climate modeling. The GLM has a robust design that benefits and improves upon its strong heritage of NASA-developed LEO predecessors, the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS). GLM will have a substantially larger number of pixels within the focal plane, two lens systems, and multiple Real-Time Event Processors REPS for on-board event detection and data compression to provide continuous observations of the Americas and adjacent oceans.

Goodman, S. J.↗
NASA NTRS2019

LiON: Lithium Oxygen Batteries for NASA Electric Aircraft

Li-Air batteries are a unique fit for electric aircraft due to their high theoretical energy densities and their potential to leverage on-board oxygen systems. Electrolytes are the limiting factor for advancing this technology. We will investigate novel "electrolyte engineering" concepts to enable Li-Air batteries with high practical energy densities, rechargeability and safety. New stable electrolytes will be designed and fabricated for Li-Air batteries and tested in an electric flight. An unprecedented "Dream Team" of experts from NASA, DOE, academia and industry will tackle this problem.

Lawson, John↗
NASA NTRSDate not supplied

A Comparison of Model Predictive Control Architectures for Application to Electrified Aircraft Propulsion Systems

As electrified aircraft propulsion (EAP) systems continue to mature, more sophisticated hardware and software are being developed to balance operations among electric machines and gas-turbine engines. In hybrid-electric propulsion systems, the increased complexity resulting from integrating turbine-engine shafts with electric machines necessitates control methodologies to account for various physical domains. Ideal controllers for hybrid-electric engines manage systems, subsystems, and their interactions in a coordinated fashion, able to account for safety and performance goals while being computationally efficient. In a previous work, linear model predictive control (MPC) schemes were implemented in centralized and distributed frameworks on a nonlinear turbofan engine model as a proof of concept. However, these schemes were not evaluated for computational complexity, prompting further study. The research presented here develops hierarchical MPC schemes to reduce the computational burden of the previous MPC schemes. A two-tier framework is implemented, where a slower sampling MPC controls electric machines and determines fan-speed tracking goals for a faster sampling controller, which is either a MPC or a proportional-integral (PI) controller. The proposed designs are compared to the centralized MPC investigated previously, and performance is measured via fan speed tracking error, energy storage state-of-charge, and computation time. Results reveal that the hierarchical MPC scheme employing a lower-level PI controller improves computation time while maintaining comparable tracking and state-of-charge regulation to the centralized scheme.

model predictive control↗
NASA NTRSDate not supplied

A Comparison of Model Predictive Control Architectures for Application to Electrified Aircraft Propulsion Systems

As electrified aircraft propulsion (EAP) systems continue to mature, more sophisticated hardware and software are being developed to balance operations among electric machines and gas-turbine engines. In hybrid-electric propulsion systems, the increased complexity resulting from integrating turbine-engine shafts with electric machines necessitates control methodologies to account for various physical domains. Ideal controllers for hybrid-electric engines manage systems, subsystems, and their interactions in a coordinated fashion, able to account for safety and performance goals while being computationally efficient. In a previous work, linear model predictive control (MPC) schemes were implemented in centralized and distributed frameworks on a nonlinear turbofan engine model as a proof of concept. However, these schemes were not evaluated for computational complexity, prompting further study. The research presented here develops hierarchical MPC schemes to reduce the computational burden of the previous MPC schemes. A two-tier framework is implemented, where a slower sampling MPC controls electric machines and determines fan-speed tracking goals for a faster sampling controller, which is either a MPC or a proportional-integral (PI) controller. The proposed designs are compared to the centralized MPC investigated previously, and performance is measured via fan speed tracking error, energy storage state-of-charge, and computation time. Results reveal that the hierarchical MPC scheme employing a lower-level PI controller improves computation time while maintaining comparable tracking and state-of-charge regulation to the centralized scheme.

model predictive control↗
NASA NTRS2021

Advanced Air Mobility and Safety Management Systems

Our current air transportation system has underserved markets, including local, regional, intraregional, and urban transportation of both people and cargo. Recent advances in aviation technology such as small highly-automated vehicles, electric aircraft, and automated air traffic are enabling business opportunities in these markets. Advanced Air Mobility, or AAM, refers to a community effort to overcome the gaps in operational rules, safety analysis, and overall acceptance, so that these new operations will be possible. For full details, please see: https://www.nasa.gov/aam As we think about how we can safely introduce these new operations, fundamental questions about how the structure of Safety Management Systems can be applied to AAM, and how that structure can be used to help us overcome the necessary technical and societal obstacles arise. Two of these questions are: • How do we tailor the requirements and desired level of monitoring and assessment to achieve safety given the breadth of possible operations and the associated risk of those operations? • How do we aid innovation by rapidly evaluating the safety of novel operations without losing associated rigor? We assume that a Safety Management System that enables these future systems will incorporate knowledge of the acceptable level of risk, and will utilize data science to automate the core monitor, assess and mitigate functions that will allow us to respond to risks and hazards in time to prevent safety incidents. In 2018, the National Academies proposed an In-Time Aviation Safety Management System (IASMS) that would advance these goals. (https://www.nap.edu/catalog/24962/in-time-aviation-safety-management-challenges-and-research-for-an) The National Academies made a clear distinction between in-time systems, in which hazards could be identified and risks mitigated in time to prevent incidents, and real-time systems, since many hazards and risks do not need real-time data and analysis to detect and mitigate.

In-Time Aviation Safety Management System↗
NASA NTRS2020

Recommendations on Use of Commercial-Off-The-Shelf (COTS) Electrical, Electronic, and Electromechanical (EEE) Parts for NASA Missions

The NASA Electronic Parts & Packaging Program Manager, requested a NASA Engineering and Safety Center independent assessment to summarize Commercial Crew Program and NASA Centers’ current and best practices, and lessons learned, on use of commercial-off-the-shelf (COTS) for all mission risk classifications, and provide recommendations that could lead to future NASA Electronic Parts and Packaging Program and/or Agency guidance on COTS parts. This document contains the outcome of the assessment.

Commercial-Off-The-Shelf↗
NASA NTRS2024

SUbsonic Single Aft eNgine (SUSAN) Power/Propulsion System Control Architecture Updates

The development of hybrid-electric propulsion technology for transport aircraft presents opportunities for new designs that can reduce fuel consumption and greenhouse gas emissions from commercial aviation and improve on safety and reliability when compared to modern aircraft. The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a conceptual design for a transport aircraft with a series/parallel partial hybrid-electric propulsion system that is being developed by NASA as a reference design for a regional transport aircraft with a high degree of electrification. The SUSAN concept incorporates multiple tightly coupled power, propulsion, and flight control systems that introduce new challenges to the control design process, requiring a hierarchical and more coordinated control architecture. This paper summarizes updates to the SUSAN Power/Propulsion System (PPS) model and control architecture made in preparation for planned flight simulator and hardware-in-the-loop testing at NASA Glenn Research Center (GRC). These updates include a new electrical power system (EPS) model based on the NASA-developed Electrical Modeling and Thermal Analysis Toolbox (EMTAT), and a new PPS control architecture that improves the operational flexibility and responsiveness of the propulsion system. The performance of the upgraded control system is also demonstrated and discussed.

SUSAN↗
NASA NTRS2024

SUbsonic Single Aft eNgine (SUSAN) Power/Propulsion System Control Architecture Updates

The development of hybrid-electric propulsion technology for transport aircraft presents opportunities for new designs that can reduce fuel consumption and greenhouse gas emissions from commercial aviation and improve on safety and reliability when compared to modern aircraft. The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a conceptual design for a transport aircraft with a series/parallel partial hybrid-electric propulsion system that is being developed by NASA as a reference design for a regional transport aircraft with a high degree of electrification. The SUSAN concept incorporates multiple tightly coupled power, propulsion, and flight control systems that introduce new challenges to the control design process, requiring a hierarchical and more coordinated control architecture. This paper summarizes updates to the SUSAN Power/Propulsion System (PPS) model and control architecture made in preparation for planned flight simulator and hardware-in-the-loop testing at NASA Glenn Research Center (GRC). These updates include a new electrical power system (EPS) model based on the NASA-developed Electrical Modeling and Thermal Analysis Toolbox (EMTAT), and a new PPS control architecture that improves the operational flexibility and responsiveness of the propulsion system. The performance of the upgraded control system is also demonstrated and discussed.

SUSAN↗
NASA NTRS1977

SCAR arrow-wing active flutter suppression system

The potential performance and direct operating cost benefits of an active flutter suppression system (FSS) for the NASA arrow-wing supersonic cruise configuration were determined. A FSS designed to increase the flutter speed of the baseline airplane 20 percent. A comparison was made of the performance and direct operating cost between the FSS equipped aircraft and a previously defined configuration with structural modifications to provide the same flutter speed. Control system synthesis and evaluation indicated that a FSS could provide the increase in flutter speed without degrading airplane reliability, safety, handling qualities, or ride quality, and without increasing repeated loads or hydraulic and electrical power capacity requirements.

Gordon, C. K.↗