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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Sensor tip for a robotic gripper and method of manufacture

A sensor tip (10) for use in a robotic hand has a three-dimensional compliant elastomeric body (12) with an outer boundary (22) having a circular base (24) and a convex surface (26) extending therefrom. Four strain transducers (14, 16, 18, and 20) produce electrical signals indicative of the strain at various positions near the boundary of the elastomeric body (12) resulting from forces exerted upon the sensor tip (10) by an object which the robotic hand is manipulating. The transducers (14, 16, 18, and 20) are positioned about the convex surface (26) so as to produce signals that may be decoupled to determine the normal and tangential forces and the applied torque. A buffer amplifier circuit (34), one for each of the transducers (14, 16, 18, and 20), receives the signals and provides quasi-steady state force information. The circuit (34) connects the respective transducer (40) in a feedback loop around an amplifier (36) and has desirable attributes for static charge buffering. The sensor tip (10) is calibrated to determine proportionality constants for the decoupling algorithm for use of a force delivering system (60), which uses voice coils (74) to apply a force that is linearly related to the current introduced to each of the coils (74). A method of manufacture of the sensor tip (10) results in improved bonding between the transducers (14, 16, 18, and 20) and the elastomeric body (12) for better performance and longer life of the sensor tip (10).

Lorenz, Robert D.↗
NASA NTRS1990

Portable hand hold device

A hand hold device (A) includes a housing (10) having a hand hold (14) and clamping brackets (32,34) for grasping and handling an object. A drive includes drive lever (23), spur gear (22), and rack gears (24,26) carried on rods (24a, 26a) for moving the clamping brackets. A lock includes ratchet gear (40) and pawl (42) biased between lock and unlock positions by a cantilever spring (46,48) and moved by handle (54). Compliant grip pads (32b, 34b) provide compliance to lock, unlock, and hold an object between the clamp brackets.

Redmon, Jr., John W.↗
NASA NTRS2008

Using Life-Cycle Human Factors Engineering to Avoid $2.4 Million in Costs: Lessons Learned from NASA's Requirements Verification Process for Space Payloads

The Human Factors Implementation Team (HFIT) process has been used to verify human factors requirements for NASA International Space Station (ISS) payloads since 2003, resulting in $2.4 million in avoided costs. This cost benefit has been realized by greatly reducing the need to process time-consuming formal waivers (exceptions) for individual requirements violations. The HFIT team, which includes astronauts and their technical staff, acts as the single source for human factors requirements integration of payloads. HFIT has the authority to provide inputs during early design phases, thus eliminating many potential requirements violations in a cost-effective manner. In those instances where it is not economically or technically feasible to meet the precise metric of a given requirement, HFIT can work with the payload engineers to develop common sense solutions and formally document that the resulting payload design does not materially affect the astronaut s ability to operate and interact with the payload. The HFIT process is fully ISO 9000 compliant and works concurrently with NASA s formal systems engineering work flow. Due to its success with payloads, the HFIT process is being adapted and extended to ISS systems hardware. Key aspects of this process are also being considered for NASA's Space Shuttle replacement, the Crew Exploration Vehicle.

Carr, Daniel↗
NASA NTRS2008

A Review of Engine Seal Performance and Requirements for Current and Future Army Engine Platforms

Sand ingestion continues to impact combat ground and air vehicles in military operations in the Middle East. The T-700 engine used in Apache and Blackhawk helicopters has been subjected to increased overhauls due to sand and dust ingestion during desert operations. Engine component wear includes compressor and turbine blades/vanes resulting in decreased engine power and efficiency. Engine labyrinth seals have also been subjected to sand and dust erosion resulting in tooth tip wear, increased clearances, and loss in efficiency. For the current investigation, a brief overview is given of the history of the T-700 engine development with respect to sand and dust ingestion requirements. The operational condition of labyrinth seals taken out of service from 4 different locations of the T-700 engine during engine overhauls are examined. Collaborative efforts between the Army and NASA to improve turbine engine seal leakage and life capability are currently focused on noncontacting, low leakage, compliant designs. These new concepts should be evaluated for their tolerance to sand laden air. Future R&D efforts to improve seal erosion resistance and operation in desert environments are recommended

Delgado, Irebert R.↗
NASA NTRS2008

Gas Foil Bearing Misalignment and Unbalance Effects

The effects of misalignment and unbalance on gas foil bearings are presented. The future of U.S. space exploration includes plans to conduct science missions aboard space vehicles, return humans to the Moon, and place humans on Mars. All of these endeavors are of long duration, and require high amounts of electrical power for propulsion, life support, mission operations, etc. One potential source of electrical power of sufficient magnitude and duration is a nuclear-fission-based system. The system architecture would consist of a nuclear reactor heat source with the resulting thermal energy converted to electrical energy through a dynamic power conversion and heat rejection system. Various types of power conversion systems can be utilized, but the Closed Brayton Cycle (CBC) turboalternator is one of the leading candidates. In the CBC, an inert gas heated by the reactor drives a turboalternator, rejects excess heat to space through a heat exchanger, and returns to the reactor in a closed loop configuration. The use of the CBC for space power and propulsion is described in more detail in the literature (Mason, 2003). In the CBC system just described, the process fluid is a high pressure inert gas such as argon, krypton, or a helium-xenon mixture. Due to the closed loop nature of the system and the associated potential for damage to components in the system, contamination of the working fluid is intolerable. Since a potential source of contamination is the lubricant used in conventional turbomachinery bearings, Gas Foil Bearings (GFB) have high potential for the rotor support system. GFBs are compliant, hydrodynamic journal and thrust bearings that use a gas, such as the CBC working fluid, as their lubricant. Thus, GFBs eliminate the possibility of contamination due to lubricant leaks into the closed loop system. Gas foil bearings are currently used in many commercial applications, both terrestrial and aerospace. Aircraft Air Cycle Machines (ACMs) and ground-based microturbines have demonstrated histories of successful long-term operation using GFBs (Heshmat et al., 2000). Small aircraft propulsion engines, helicopter gas turbines, and high-speed electric motors are potential future applications.

Howard, Samuel A.↗
NASA NTRS2008

Status of the AIAA Modeling and Simulation Format Standard

The current draft AIAA Standard for flight simulation models represents an on-going effort to improve the productivity of practitioners of the art of digital flight simulation (one of the original digital computer applications). This initial release provides the capability for the efficient representation and exchange of an aerodynamic model in full fidelity; the DAVE-ML format can be easily imported (with development of site-specific import tools) in an unambiguous way with automatic verification. An attractive feature of the standard is the ability to coexist with existing legacy software or tools. The draft Standard is currently limited in scope to static elements of dynamic flight simulations; however, these static elements represent the bulk of typical flight simulation mathematical models. It is already seeing application within U.S. and Australian government agencies in an effort to improve productivity and reduce model rehosting overhead. An existing tool allows import of DAVE-ML models into a popular simulation modeling and analysis tool, and other community-contributed tools and libraries can simplify the use of DAVE-ML compliant models at compile- or run-time of high-fidelity flight simulation.

Jackson, E. Bruce↗
NASA NTRS2008

Open Architecture Standard for NASA's Software-Defined Space Telecommunications Radio Systems

NASA is developing an architecture standard for software-defined radios used in space- and ground-based platforms to enable commonality among radio developments to enhance capability and services while reducing mission and programmatic risk. Transceivers (or transponders) with functionality primarily defined in software (e.g., firmware) have the ability to change their functional behavior through software alone. This radio architecture standard offers value by employing common waveform software interfaces, method of instantiation, operation, and testing among different compliant hardware and software products. These common interfaces within the architecture abstract application software from the underlying hardware to enable technology insertion independently at either the software or hardware layer. This paper presents the initial Space Telecommunications Radio System (STRS) Architecture for NASA missions to provide the desired software abstraction and flexibility while minimizing the resources necessary to support the architecture.

Reinhart, Richard C.↗
NASA NTRS2006

A Theoretical Investigation of Composite Overwrapped Pressure Vessel (COPV) Mechanics Applied to NASA Full Scale Tests

A theoretical investigation of the factors controlling the stress rupture life of the National Aeronautics and Space Agency's (NASA) composite overwrapped pressure vessels (COPVs) continues. Kevlar(TradeMark) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar(TradeMark) filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However, due to the presence of a load sharing liner, the manufacturing induced residual stresses and the complex mechanical response, the state of actual fiber stress in flight hardware and test articles is not clearly known. This paper is a companion to the experimental investigation reported in [1] and develops a theoretical framework necessary to design full-scale pathfinder experiments and accurately interpret the experimentally observed deformation and failure mechanisms leading up to static burst in COPVs. The fundamental mechanical response of COPVs is described using linear elasticity and thin shell theory and discussed in comparison to existing experimental observations. These comparisons reveal discrepancies between physical data and the current analytical results and suggest that the vessel's residual stress state and the spatial stress distribution as a function of pressure may be completely different from predictions based upon existing linear elastic analyses. The 3D elasticity of transversely isotropic spherical shells demonstrates that an overly compliant transverse stiffness relative to membrane stiffness can account for some of this by shifting a thin shell problem well into the realm of thick shell response. The use of calibration procedures are demonstrated as calibrated thin shell model results and finite element results are shown to be in good agreement with the experimental results. The successes reported here have lead to continuing work with full scale testing of larger NASA COPV hardware.

Greene, N.↗
NASA NTRS2007

Scientific Uses and Directions of SPDF Data Services

From a science user's perspective, the multi-mission data and orbit services of NASA's Space Physics Data Facility (SPDF) project perform as a working and highly functional heliophysics virtual observatory. CDAWeb enables plots, listings and file downloads for current data across the boundaries of missions and instrument types (and now including data from THEMIS and STEREO), VSPO access to a wide range of distributed data sources. SSCWeb, Helioweb and our 3D Animated Orbit Viewer (TIPSOD) provide position data and query logic for most missions currently-important to heliophysics science. OMNIWeb with its new extension to 1- and 5- minute resolution provides interplanetary parameters at the Earth's bow shock as a unique value-added data product. To enable easier integrated use of our capabilities by developers and by the emerging heliophysics VxOs, our data and services are available through webservices-based APls as well as through our direct user interfaces. SPDF has also now developed draft descriptions of its holdings in SPASE-compliant XML In addition to showcasing recent enhancements to SPDF capabilities, we will use these systems and our experience in developing them: to demonstrate a few typical science use cases; to discuss key scope and design issues among users, service providers and end data providers; and to identify key areas where existing capabilities and effective interface design are still inadequate to meet community needs.

Fung, Shing↗
NASA NTRS2008

Pharmacy in a New Frontier - The First Five Years at the Johnson Space Center Pharmacy

A poster entitled "Space Medicine - A New Role for Clinical Pharmacists" was presented in December 2001 highlighting an up-and-coming role for pharmacists at the Johnson Space Center (JSC) in Houston, Texas. Since that time, the operational need for the pharmacy profession has expanded with the administration s decision to open a pharmacy on site at JSC to complement the care provided by the Flight Medicine and Occupational Medicine Clinics. The JSC Pharmacy is a hybrid of traditional retail and hospital pharmacy and is compliant with the ambulatory care standards set forth by the Joint Commission. The primary charge for the pharmacy is to provide medication management for JSC. In addition to providing ambulatory care for both clinics, the pharmacists also practice space medicine. A pharmacist had been involved in the packing of both the Space Shuttle and International Space Station Medical Kits before the JSC Pharmacy was established; however, the role of the pharmacist in packing medical kits has grown. The pharmacists are now full members of the operations team providing consultation for new drug delivery systems, regulations, and patient safety issues. As the space crews become more international, so does the drug information provided by the pharmacists. This presentation will review the journey of the JSC Pharmacy as it celebrated its five year anniversary in April of 2008. The implementation of the pharmacy, challenges to the incorporation of the pharmacy into an existing health-care system, and the current responsibilities of a pharmacist at the Johnson Space Center will be discussed.

Bayuse, Tina↗
NASA NTRS2009

OTF CCSDS Mission Operations Prototype Parameter Service. Phase I: Exit Presentation

This slide presentation reviews the prototype of phase 1 of the parameter service design of the CCSDS mission operations. The project goals are to: (1) Demonstrate the use of Mission Operations standards to implement the Parameter Service (2) Demonstrate interoperability between Houston MCC and a CCSDS Mission Operations compliant mission operations center (3) Utilize Mission Operations Common Architecture. THe parameter service design, interfaces, and structures are described.

Reynolds, Walter F.↗
NASA NTRS2008

Ring Bus Architecture for a Solid-State Recorder

A document concisely describes a ring bus architecture for a proposed solid-state recorder (SSR) that would serve as buffer of data to be transmitted from a spacecraft to Earth. This architecture would afford fault tolerance needed for reliable operation in an anticipated high-radiation environment in which traditional SSRs cannot operate reliably. Features of the architecture include one or more controller boards and multiple memory boards interconnected in a ringlike topology. The interconnections would be high-speed serial links complying with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus). Accordingly, each controller and memory board would be equipped with an IEEE-1393-compliant ring-bus-interface unit. The ringlike topology and the multiplicity of memory boards (and, optionally, of controller boards) would afford the redundancy needed for fault tolerance. Each board would be a fault-containment region. The IEEE 1393 links could be routed so that the SSR would continue to function even in the event of multiple failures. This architecture would also support scalability over a wide range. In a fully redundant configuration, it could accommodate between 1 and 125 memory boards.

Walker, W. John↗
NASA NTRS2008

All-Organic Actuator Fabricated with Single Wall Carbon Nanotube Electrodes

Compliant electrodes to replace conventional metal electrodes have been required for many actuators to relieve the constraint on the electroactive layer. Many conducting polymers have been proposed for the alternative electrodes, but they still have a problem of poor thermal stability. This article reports a novel all-organic actuator with single wall carbon nanotube (SWCNT) films as the alternative electrode. The SWCNT film was obtained by filtering a SWCNT solution through an anodized alumina membrane. The conductivity of the SWCNT film was about 280 S/cm. The performance of the SWCNT film electrode was characterized by measuring the dielectric properties of NASA Langley Research Center - Electroactive Polymer (LaRC-EAP) sandwiched by the SWCNT electrodes over a broad range of temperature (from 25 C to 280 C) and frequency (from 1 KHz to 1 MHz). The all-organic actuator with the SWCNT electrodes showed a larger electric field-induced strain than that with metal electrodes, under identical measurement conditions.

Lowther, Sharon E.↗
NASA NTRS2009

A Theoretical Investigation of Composite Overwrapped Pressure Vessel (COPV) Mechanics Applied to NASA Full Scale Tests

A theoretical investigation of the factors controlling the stress rupture life of the National Aeronautics and Space Administration's (NASA) composite overwrapped pressure vessels (COPVs) continues. Kevlar (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of a load sharing liner, the manufacturing induced residual stresses and the complex mechanical response, the state of actual fiber stress in flight hardware and test articles is not clearly known. This paper is a companion to a previously reported experimental investigation and develops a theoretical framework necessary to design full-scale pathfinder experiments and accurately interpret the experimentally observed deformation and failure mechanisms leading up to static burst in COPVs. The fundamental mechanical response of COPVs is described using linear elasticity and thin shell theory and discussed in comparison to existing experimental observations. These comparisons reveal discrepancies between physical data and the current analytical results and suggest that the vessel s residual stress state and the spatial stress distribution as a function of pressure may be completely different from predictions based upon existing linear elastic analyses. The 3D elasticity of transversely isotropic spherical shells demonstrates that an overly compliant transverse stiffness relative to membrane stiffness can account for some of this by shifting a thin shell problem well into the realm of thick shell response. The use of calibration procedures are demonstrated as calibrated thin shell model results and finite element results are shown to be in good agreement with the experimental results. The successes reported here have lead to continuing work with full scale testing of larger NASA COPV hardware.

Thesken, John C.↗
NASA NTRS2007

State-Chart Autocoder

A computer program translates Unified Modeling Language (UML) representations of state charts into source code in the C, C++, and Python computing languages. ( State charts signifies graphical descriptions of states and state transitions of a spacecraft or other complex system.) The UML representations constituting the input to this program are generated by using a UML-compliant graphical design program to draw the state charts. The generated source code is consistent with the "quantum programming" approach, which is so named because it involves discrete states and state transitions that have features in common with states and state transitions in quantum mechanics. Quantum programming enables efficient implementation of state charts, suitable for real-time embedded flight software. In addition to source code, the autocoder program generates a graphical-user-interface (GUI) program that, in turn, generates a display of state transitions in response to events triggered by the user. The GUI program is wrapped around, and can be used to exercise the state-chart behavior of, the generated source code. Once the expected state-chart behavior is confirmed, the generated source code can be augmented with a software interface to the rest of the software with which the source code is required to interact.

Clark, Kenneth↗
NASA NTRS2009

An Overview of Non-Metallic Brush Seal Technology

Non-metallic brush seals are ultra-low flow sealing elements ideal for low pressure differentials (<30 psid) and low temperature (typically <300 degF) applications. The compliant bristle pack of a non-metallic brush seal is advantageous in terms of sealing capability during transients. However, if not designed properly, the bristle pack compliance can be detrimental to the performance of the seal. GE GLobal Research has investigated the stiffness and heat generation properties of non-metallic brush seals made from Kevlar and Carbon Fiber. The presentation will review the progress made on the design points of the seals, as well as highlight some current commercial applications of the technology.

Ruggiero, Eric J.↗
NASA NTRS2007

Web-Based Real-Time Emergency Monitoring

The Web-based Real-Time Asset Monitoring (RAM) module for emergency operations and facility management enables emergency personnel in federal agencies and local and state governments to monitor and analyze data in the event of a natural disaster or other crisis that threatens a large number of people and property. The software can manage many disparate sources of data within a facility, city, or county. It was developed on industry-standard Geo- Spatial software and is compliant with open GIS standards. RAM View can function as a standalone system, or as an integrated plugin module to Emergency Operations Center (EOC) software suites such as REACT (Real-time Emergency Action Coordination Tool), thus ensuring the widest possible distribution among potential users. RAM has the ability to monitor various data sources, including streaming data. Many disparate systems are included in the initial suite of supported hardware systems, such as mobile GPS units, ambient measurements of temperature, moisture and chemical agents, flow meters, air quality, asset location, and meteorological conditions. RAM View displays real-time data streams such as gauge heights from the U.S. Geological Survey gauging stations, flood crests from the National Weather Service, and meteorological data from numerous sources. Data points are clearly visible on the map interface, and attributes as specified in the user requirements can be viewed and queried.

Harvey, Craig A.↗
NASA NTRS2010

Evaluation of Gear Condition Indicator Performance on Rotorcraft Fleet

The U.S. Army is currently expanding its fleet of Health Usage Monitoring Systems (HUMS) equipped aircraft at significant rates, to now include over 1,000 rotorcraft. Two different on-board HUMS, the Honeywell Modern Signal Processing Unit (MSPU) and the Goodrich Integrated Vehicle Health Management System (IVHMS), are collecting vibration health data on aircraft that include the Apache, Blackhawk, Chinook, and Kiowa Warrior. The objective of this paper is to recommend the most effective gear condition indicators for fleet use based on both a theoretical foundation and field data. Gear diagnostics with better performance will be recommended based on both a theoretical foundation and results of in-fleet use. In order to evaluate the gear condition indicator performance on rotorcraft fleets, results of more than five years of health monitoring for gear faults in the entire HUMS equipped Army helicopter fleet will be presented. More than ten examples of gear faults indicated by the gear CI have been compiled and each reviewed for accuracy. False alarms indications will also be discussed. Performance data from test rigs and seeded fault tests will also be presented. The results of the fleet analysis will be discussed, and a performance metric assigned to each of the competing algorithms. Gear fault diagnostic algorithms that are compliant with ADS-79A will be recommended for future use and development. The performance of gear algorithms used in the commercial units and the effectiveness of the gear CI as a fault identifier will be assessed using the criteria outlined in the standards in ADS-79A-HDBK, an Army handbook that outlines the conversion from Reliability Centered Maintenance to the On-Condition status of Condition Based Maintenance.

Antolick, Lance J.↗