Search NASA⌕ Search

SEARCH · Search NASA

Results for “vehicle efficiencies”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Failure Analysis at the Kennedy Space Center

History has shown that failures occur in every engineering endeavor, and what we learn from those failures contributes to the knowledge base to safely complete future missions. The necessity of failure analysis is at its apex at the end of one aged program and at the beginning of a new and untested program. The information that we gain through failure analysis corrects the deficiencies in the current vehicle to make the next generation of vehicles more efficient and safe. The Failure Analysis and Materials Evaluation Branch in the Materials Science Division at the Kennedy Space Center performs metallurgical, mechanical, electrical, and non-metallic materials failure analyses and accident investigations on both flight hardware and ground support equipment for the Space Shuttle, International Space Station, Constellation, and Launch Services Programs. This paper will explore a variety of failure case studies at the Kennedy Space Center and the lessons learned that can be applied in future programs.

Salazar, Victoria L.↗
NASA NTRS2010

Failure Analysis at the Kennedy Space Center

History has shown that failures occur in every engineering endeavor, and what we learn from those failures contributes to the knowledge base to safely complete future missions. The necessity of failure analysis is at its apex at the end of one aged program (i.e. Shuttle) and at the beginning of a new and untested program (i.e. Constellation). The information that we gain through failure analysis corrects the deficiencies in the current vehicle to make the next generation of vehicles more efficient and safe. The Failure Analysis and Materials Evaluation section in the Materials Science Division at the Kennedy Space Center performs metallurgical, mechanical, electrical, and non-metallic failure analysis and accident investigations on both flight hardware and ground support equipment (GSE) for the Shuttle, International Space Station, Constellation, and Launch Services Programs. This presentation will explore a variety of failure case studies at KSC and the lessons learned that can be applied in future programs.

Salazar, Victoria L.↗
NASA NTRS2015

Exploring Propulsion System Requirements for More and All-Electric Helicopters

Helicopters offer unique capabilities that are important for certain missions. More and all-electric propulsion systems for helicopters offer the potential for improved efficiency, reliability, vehicle and mission capabilities as well as reduced harmful emissions. To achieve these propulsion system-based benefits, the relevant requirements must be understood and developed for the various component, sub-component and ancillary systems of the overall propulsion system. Three representative helicopters were used to explore propulsion and overall vehicle and mission requirements. These vehicles varied from light utility (one to three occupants) to highly capable (three crew members plus ten passengers and cargo). Assuming 15 and 30 year technology availability, analytical models for electric system components were developed to understand component and ancillary requirements. Overall propulsion system characteristics were developed and used for vehicle sizing and mission analyses to understand the tradeoffs of component performance and weight, with increase in vehicle size and mission capability. Study results indicate that only the light utility vehicle retained significant payload for an arbitrary 100 nautical mile range assuming 15 year technology. Thirty year technology assumptions for battery energy storage are sufficient to enable some range and payload capabilities, but further improvements in energy density are required to maintain or exceed payload and range capabilities versus present systems. Hydrocarbon-fueled range extenders can be prudently used to recover range and payload deficiencies resulting from battery energy density limitations. Thermal loads for electric systems are low heat quality, but seem manageable. To realize the benefits from more and all-electric systems, technology goals must be achieved, as well as vehicles, missions and systems identified that are best suited to take advantage of their unique characteristics.

mission analysis↗
NASA NTRS2015

Exploring Propulsion System Requirements for More and All-Electric Helicopters

Helicopters offer unique capabilities that are important for certain missions. More and all-electric propulsion systems for helicopters offer the potential for improved efficiency, reliability, vehicle and mission capabilities as well as reduced harmful emissions. To achieve these propulsion system-based benefits, the relevant requirements must be understood and developed for the various component, sub-component and ancillary systems of the overall propulsion system. Three representative helicopters were used to explore propulsion and overall vehicle and mission requirements. These vehicles varied from light utility (one to three occupants) to highly capable (three crew members plus ten passengers and cargo). Assuming 15 and 30 year technology availability, analytical models for electric system components were developed to understand component and ancillary requirements. Overall propulsion system characteristics were developed and used for vehicle sizing and mission analyses to understand the tradeoffs of component performance and weight, with increase in vehicle size and mission capability. Study results indicate that only the light utility vehicle retained significant payload for an arbitrary 100 nautical mile range assuming 15 year technology. Thirty year technology assumptions for battery energy storage are sufficient to enable some range and payload capabilities, but further improvements in energy density are required to maintain or exceed payload and range capabilities versus present systems. Hydrocarbon-fueled range extenders can be prudently used to recover range and payload deficiencies resulting from battery energy density limitations. Thermal loads for electric systems are low heat quality, but seem manageable. To realize the benefits from more and all-electric systems, technology goals must be achieved, as well as identify vehicles, missions and systems that are best suited to take advantage of their unique characteristics.

gearbox↗
NASA NTRS2016

Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft

The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid-electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid-electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of AC and DC for power transmission. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power generation, transmission, and distribution systems, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of dual-fed induction machines, which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the project along with the system architecture, development status and preliminary results.

Propulsion↗
NASA NTRS2017

Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft

The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as strategic thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of alternating current (AC) and direct current (DC) for power generation, transmission, and distribution. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power system, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of doubly-fed induction machines (DFIMs), which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the activity along with the system architecture, development status, and preliminary results.

Sadey, David J.↗
NASA NTRS2018

Propulsion Control Technology Development Needs to Address NASA Aeronautics Research Mission Goals for Thrusts 3a and 4

The Commercial Aero-Propulsion Control Working Group (CAPCWG), consisting of propulsion control technology leads from The Boeing Company, GE Aviation, Honeywell, Pratt & Whitney, Rolls-Royce, and NASA (National Aeronautics and Space Administration) Glenn Research Center, has been working together over the past year to identify propulsion control technology areas of common interest that we believe are critical to achieving the challenging NASA Aeronautics Research goals for Thrust 3a: Ultra-Efficient Commercial Vehicles - Subsonic Transports, and Thrust 4: Transition to Alternative Propulsion and Energy. This paper describes the various propulsion control technology development areas identified by CAPCWG as most critical for NASA to invest in. For Thrust 3a these are: i) Integrated On-Board Model Based Engine Control and Health Management; ii) Flexible and Modular Networked Control Hardware and Software Architecture; iii) Intelligent Air/Fuel Control for Low Emissions Combustion; and iv) Active Clearance Control. For Thrust 4a, the focus is on Hybrid Electric Propulsion (HEP) for single aisle commercial aircraft. The specific technology development areas include: i) Integrated Power and Propulsion System Dynamic Modeling for Control; ii) Control Architectures for HEP; iii) HEP Control Verification and Validation; and iv) Engine/Airplane Control Integration. For each of the technology areas, the discussion includes: problem to be solved and how it relates to NASA goals, and the challenges to be addressed in reducing risk.

Propulsion Control↗
NASA NTRS2017

Design of Multifunctional Hierarchical Space Structures

We describe a system for the design of space structures with tunable structural properties based on the discrete assembly of modular lattice elements. These lattice elements can be constructed into larger beam-like elements, which can then be assembled into large scale truss structures. These discrete lattice elements are reversibly assembled with mechanical fasteners, which allows them to be arbitrarily reconfigured into various application-specific designs. In order to assess the validity of this approach, we design two space structures with similar geometry but widely different structural requirements: an aerobrake, driven by strength requirements, and a precision segmented reflector, driven by stiffness and accuracy requirements. We will show agreement between simplified numerical models based on hierarchical assembly and analytical solutions. We will also present an assessment of the error budget resulting from the assembly of discrete structures. Lastly, we will address launch vehicle packing efficiency issues for transporting these structures to lower earth orbit.

Aeronautics↗
NASA NTRS2020

End-to-End Assessment of Artemis-1 Development Flight Instrumentation

As the space industry continues to strive for more efficient launch vehicles they must rely on increasingly accurate predictive models. Verification of models typically requires physical testing. Flight data measurements offer the most real and therefore the most accurate data for model correlation. As NASA prepares for the inaugural launch of their new Space Launch System (SLS), Artemis-1, they must rely heavily on predictive system models to ensure flight safety. Artemis-1 will be an unmanned scientific mission with the intent of blazing a trail for future manned missions. NASA has implemented a system of Development Flight Instrumentation (DFI) in the hopes of recovering useful flight data during liftoff and ascent to aid in correlating their predictive models to ensure human safety in future missions. An end-to-end assessment of the DFI system was performed to verify data acquired during Artemis-1 would be adequate for the targeted flight test objectives (FTOs). This was accomplished using a computational simulation of all sensors and Data Acquisition (DAQ) parameters to investigate any potential problem areas in the current architecture. Input nominal signals were approximated and injected into the system model. Synthesized acquired signals were recovered to verify FTO success.

Flight measurement↗
NASA NTRSDate not supplied

Assessment of Artemis-1 Pogo Flight Instrumentation System

As the space industry continues to strive for more efficient launch vehicles, it must relyon increasingly accurate predictive models. Verification of models typically requires physical testing. Flight data measurements offer the most real and therefore the most accurate data for model correlation. As NASA prepares for the inaugural launch of Space Launch System(SLS), Artemis-1, they must rely heavily on predictive system models to ensure flight safety.NASA has implemented a Development Flight Instrumentation (DFI) system in hopes of recovering useful flight data to aid in model correlation. Historically, some of the most important flight measurements are those that monitor the potentially destructive dynamic interaction of the structural and propellant modes – a phenomenon known as pogo. Pogo is a dynamic instability that can occur on a launch vehicle during any phase of ascent. During this investigation an end-to-end assessment of the Artemis-I Pogo-related DFI was performed to identify any obstacles inherent in the current instrumentation system which may prevent successful measurement of the data necessary to validate the current predictive fluid-structural models. Input drive signals were approximated and applied to a state-space system model to derive predicted pressure and acceleration responses. These predicted responses were then fed through a simulation of the data acquisition process in order to recover predicted measurements. Finally, a mock Flight Data Analysis (FDA) was performed to assess the ability of these measurements to meet the Flight Test Objectives(FTO).

Adam Johnson↗
NASA NTRSDate not supplied

Assessment of Artemis-1 Pogo Flight Instrumentation System

As the space industry continues to strive for more efficient launch vehicles, it must rely on increasingly accurate predictive models. Verification of models typically requires physical testing. Flight data measurements offer the most real and therefore the most accurate data for model correlation. As NASA prepares for the inaugural launch of Space Launch System (SLS), Artemis-1, they must rely heavily on predictive system models to ensure flight safety. NASA has implemented a Development Flight Instrumentation (DFI) system in hopes of recovering useful flight data to aid in model correlation. Historically, some of the most important flight measurements are those that monitor the potentially destructive dynamic interaction of the structural and propellant modes – a phenomenon known as pogo. Pogo is a dynamic instability that can occur on a launch vehicle during any phase of ascent. During this investigation an end-to-end assessment of the Artemis-I Pogo-related DFI was performed to identify any obstacles inherent in the current instrumentation system which may prevent successful measurement of the data necessary to validate the current predictive models of the Main Propulsion System (MPS). Input drive signals were approximated and applied to a system-level SLS state-space model to derive predicted pressure and acceleration responses. These predicted responses were then fed through a simulation of the data acquisition process in order to recover predicted measurements. Finally, a mock Flight Data Analysis (FDA) was performed to assess the ability of these measurements to meet the Flight Test Objectives (FTO).

Adam Johnson↗
NASA NTRSDate not supplied

Historical Domestic Flights from 2016-2020 with Estimations of Greenhouse Gas Emissions by Aircraft Type

Data and analyses are presented on the utilization of aircraft fuel in the U.S. and the greenhouse gas emissions that they create. Aggregated commercial passenger and freight aviation flight data from 2016-2020 is captured from the Bureau of Transportation Statistics website is used to augment flight data from the Sherlock data warehouse at NASA Ames is used to determine the miles flown by major aircraft models. The corresponding fuel burn is estimated using the International Civilian Aviation Organization fuel burn tables and carbon dioxide emissions are calculated using a fuel-burn multiplicative factor. One key conclusion of this analysis is that long haul flights (i.e. >2485 statute miles) create a disproportionately large amount of carbon dioxide emissions in the U.S while short flights (i.e. < 311 statute miles) contribute less than five percent of the U.S. aviation-related carbon dioxide emission. Although these short-haul flights may not have a large impact on overall carbon dioxide emissions, they will be a critical entry point for the adoption of future, larger fuel-efficient novel vehicles and the impact to future airport and infrastructure requirements. The final paper will present some estimates of the impact of advanced technologies on fuel burn and CO₂ emissions in various scenarios.

Susie Go↗
NASA NTRS2017

Computationally Efficient Motion Planning Algorithms for Agile Autonomous Vehicles in Cluttered Environments

Fast, real-time motion planning of an agile, autonomous vehicle in a cluttered environment, with many geometrically-fixed obstacles, is a very complex problem, especially because of the vehicle dynamics constraints and resource constrained computational capabilities onboard the vehicle. In this paper, we present computationally-efficient versions of our novel motion planning algorithm called the Spherical Expansion and Sequential Convex Programming (SE–SCP) algorithm. The SE–SCP algorithm first uses a spherical-expansion-based randomized sampling algorithm to explore the workspace. Oncea path is found from the start position to the goal position, the algorithm computes a locally optimal trajectory, within its homotopy class for a desired cost function, by solving a sequence of convex optimization problems. Thus, the SE–SCP algorithm is anytime locally optimal and the trajectory is globally optimal if the number of samples tends to infinity. In this paper, we further enhance the computational efficiency of the SE–SCP algorithm using uni-directional and bi-directional rewiring techniques. We also present a detailed proof of the local optimality characteristics of the new SE–SCP algorithms for aspecial case of vehicle dynamics. Simulation examples involving quadrotor and spacecraft help demonstrate the effectiveness of our new algorithms.

Bandyopadhyay, Saptarshi↗
NASA NTRS1984

Human response to vibroacoustic environments of space vehicles

To insure efficient utilization of the system, space station design and operations will require special habitability considerations for the occupants and crew because of the relatively long duration missions. Of particular concern is the environment in which the personnel will live and work, and how it affects both the performance and comfort of the occupants. Current criteria do not consider possible effects of reduced gravity, long duration, and confinement. Preliminary to developing space station vibroacoustic habitability criteria, the adequacy of criteria for other space vehicles has been reviewed. In this paper, responses to the noise and vibration environments of both Skylab and Shuttle are discussed. Some astronauts have reported sleep interference, communication interference, distraction, and general annoyance as noise related complaints. In addition, information from the Russian Salyut missions, as well as similar based situtations (e.g., submarines), is reviewed.

Willshire, K. F.↗
NASA NTRS1983

NASA/GE Energy Efficient Engine low pressure turbine scaled test vehicle performance report

The low pressure turbine for the NASA/General Electric Energy Efficient Engine is a highly loaded five-stage design featuring high outer wall slope, controlled vortex aerodynamics, low stage flow coefficient, and reduced clearances. An assessment of the performance of the LPT has been made based on a series of scaled air-turbine tests divided into two phases: Block 1 and Block 2. The transition duct and the first two stages of the turbine were evaluated during the Block 1 phase from March through August 1979. The full five-stage scale model, representing the final integrated core/low spool (ICLS) design and incorporating redesigns of stages 1 and 2 based on Block 1 data analysis, was tested as Block 2 in June through September 1981. Results from the scaled air-turbine tests, reviewed herein, indicate that the five-stage turbine designed for the ICLS application will attain an efficiency level of 91.5 percent at the Mach 0.8/10.67-km (35,000-ft), max-climb design point. This is relative to program goals of 91.1 percent for the ICLS and 91.7 percent for the flight propulsion system (FPS).

Bridgeman, M. J.↗
NASA NTRS1993

Lunar transportation system

The University Space Research Association (USRA) requested the University of Minnesota Spacecraft Design Team to design a lunar transportation infrastructure. This task was a year long design effort culminating in a complete conceptual design and presentation at Johnson Space Center. The mission objective of the design group was to design a system of vehicles to bring a habitation module, cargo, and crew to the lunar surface from LEO and return either or both crew and cargo safely to LEO while emphasizing component commonality, reusability, and cost effectiveness. During the course of the design, the lunar transportation system (LTS) has taken on many forms. The final design of the system is composed of two vehicles, a lunar transfer vehicle (LTV) and a lunar excursion vehicle (LEV). The LTV serves as an efficient orbital transfer vehicle between the earth and the moon while the LEV carries crew and cargo to the lunar surface. Presented in the report are the mission analysis, systems layout, orbital mechanics, propulsion systems, structural and thermal analysis, and crew systems, avionics, and power systems for this lunar transportation concept.

Source record↗
DOE OSTI2024

Potential Adoption and Benefits of Co-Optimized Multimode Engines and Fuels for U.S. Light-Duty Vehicles

Exploring a diverse portfolio of technologies for decarbonization is crucial to understanding the potential impacts of different technological solutions and their associated environmental implications. Using high-octane, high-sensitivity biofuel blends in co-optimized multimode engines can increase engine efficiency and reduce vehicle emissions. Here, the multimode engine research focuses on the benefits of light-duty vehicle engines, which can operate in multiple modes depending on the vehicle's load. Low-temperature combustion can improve efficiency and reduce emissions (such as those from oxides of nitrogen and particulate matter) during low-load operation, while spark ignition performance is maintained in high-load operation. These advanced engines can be optimized to run on blends of biobased fuels. This analysis models scenarios for potential market adoption of co-optimized multimode vehicles fueled by three different bioblendstocks: ethanol, isopropanol, and isobutanol. An integrated modeling approach is used to forecast the energy and environmental impacts of the deployment of co-optimized multimode vehicles and fuels in the light-duty sector over the 2020-to-2050 time horizon. The multidisciplinary approach combines vehicle sales modeling, system dynamics modeling of the biorefining industry, and life cycle assessment to estimate the emissions and energy benefits. The models consider market forces such as consumer preferences for vehicle attributes, biofuel supply and demand dynamics subject to biorefinery capacity build-out and bioresource constraints, and forecasted changes to the U.S. bulk energy system over time. Market adoption of co-optimized vehicles is evaluated across a wide parameter space for incremental vehicle cost and engine efficiency improvement. This analysis reveals that the deployment of co-optimized multimode fuels and vehicles results in up to a 5% reduction in annual sector-wide life cycle greenhouse gas (GHG) emissions by 2050, relative to a business-as-usual scenario, but is also indicates environmental trade-offs, such as higher life cycle water-use. Emission benefits could potentially increase beyond 2050, as the new technologies penetrate the market and gain a foothold. Results also show that, under certain circumstances, vehicles with engines co-optimized for use with high-octane, high-sensitivity biofuel blends can be cost-competitive with conventional gasoline, while reducing GHG emissions. Our modeling results indicate that co-optimized multimode fuels and engines can be strategically leveraged in tandem with electrification to decarbonize the light-duty sector. Co-optimized vehicles could play a role in the early years of the time horizon, while electric vehicles (EVs) could become more competitive in the later years, highlighting the complementary benefits of these technologies for GHG reductions.

Oke, Doris↗
NASA NTRS2011

Hybrid Power Management-Based Vehicle Architecture

Hybrid Power Management (HPM) is the integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications (s ee figure). The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The basic vehicle architecture consists of a primary power source, and possibly other power sources, that provides all power to a common energy storage system that is used to power the drive motors and vehicle accessory systems. This architecture also provides power as an emergency power system. Each component is independent, permitting it to be optimized for its intended purpose. The key element of HPM is the energy storage system. All generated power is sent to the energy storage system, and all loads derive their power from that system. This can significantly reduce the power requirement of the primary power source, while increasing the vehicle reliability. Ultracapacitors are ideal for an HPM-based energy storage system due to their exceptionally long cycle life, high reliability, high efficiency, high power density, and excellent low-temperature performance. Multiple power sources and multiple loads are easily incorporated into an HPM-based vehicle. A gas turbine is a good primary power source because of its high efficiency, high power density, long life, high reliability, and ability to operate on a wide range of fuels. An HPM controller maintains optimal control over each vehicle component. This flexible operating system can be applied to all vehicles to considerably improve vehicle efficiency, reliability, safety, security, and performance. The HPM-based vehicle architecture has many advantages over conventional vehicle architectures. Ultracapacitors have a much longer cycle life than batteries, which greatly improves system reliability, reduces life-of-system costs, and reduces environmental impact as ultracapacitors will probably never need to be replaced and disposed of. The environmentally safe ultracapacitor components reduce disposal concerns, and their recyclable nature reduces the environmental impact. High ultracapacitor power density provides high power during surges, and the ability to absorb high power during recharging. Ultracapacitors are extremely efficient in capturing recharging energy, are rugged, reliable, maintenance-free, have excellent lowtemperature characteristic, provide consistent performance over time, and promote safety as they can be left indefinitely in a safe, discharged state whereas batteries cannot.

Eichenberg, Dennis J.↗