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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Carbon Dioxide Dispersion in the Combustion Integrated Rack Simulated Numerically

When discharged into an International Space Station (ISS) payload rack, a carbon dioxide (CO2) portable fire extinguisher (PFE) must extinguish a fire by decreasing the oxygen in the rack by 50 percent within 60 sec. The length of time needed for this oxygen reduction throughout the rack and the length of time that the CO2 concentration remains high enough to prevent the fire from reigniting is important when determining the effectiveness of the response and postfire procedures. Furthermore, in the absence of gravity, the local flow velocity can make the difference between a fire that spreads rapidly and one that self-extinguishes after ignition. A numerical simulation of the discharge of CO2 from PFE into the Combustion Integrated Rack (CIR) in microgravity was performed to obtain the local velocity and CO2 concentration. The complicated flow field around the PFE nozzle exits was modeled by sources of equivalent mass and momentum flux at a location downstream of the nozzle. The time for the concentration of CO2 to reach a level that would extinguish a fire anywhere in the rack was determined using the Fire Dynamics Simulator (FDS), a computational fluid dynamics code developed by the National Institute of Standards and Technology specifically to evaluate the development of a fire and smoke transport. The simulation shows that CO2, as well as any smoke and combustion gases produced by a fire, would be discharged into the ISS cabin through the resource utility panel at the bottom of the rack. These simulations will be validated by comparing the results with velocity and CO2 concentration measurements obtained during the fire suppression system verification tests conducted on the CIR in March 2003. Once these numerical simulations are validated, portions of the ISS labs and living areas will be modeled to determine the local flow conditions before, during, and after a fire event. These simulations can yield specific information about how long it takes for smoke and combustion gases produced by a fire to reach a detector location, how large the fire would be when the detector alarms, and the behavior of the fire until it has been extinguished. This new capability could then be used to optimize the location of fire detectors and fire-suppression ports as well as to evaluate the effectiveness of fire suppressants and response strategies. Numerical data collected from these simulations could also be used to develop a virtual reality fire event for crew training and fire safety awareness. This work is funded by NASA's Bioastronautics Initiative, which has the objective of ensuring and enhancing the health, safety, and performance of humans in space. As part of this initiative, the Microgravity Combustion Science Branch at the NASA Glenn Research Center is conducting spacecraft fire safety research to significantly improve fire safety on inhabited spacecraft.

Wu, Ming-Shin↗
NASA NTRS2007

Stroboscopic Vision as a Treatment for Retinal Slip Induced Motion Sickness

Motion sickness in the general population is a significant problem driven by the increasingly more sophisticated modes of transportation, visual displays, and virtual reality environments. It is important to investigate non-pharmacological alternatives for the prevention of motion sickness for individuals who cannot tolerate the available anti-motion sickness drugs, or who are precluded from medication because of different operational environments. Based on the initial work of Melvill Jones, in which post hoc results indicated that motion sickness symptoms were prevented during visual reversal testing when stroboscopic vision was used to prevent retinal slip, we have evaluated stroboscopic vision as a method of preventing motion sickness in a number of different environments. Specifically, we have undertaken a five part study that was designed to investigate the effect of stroboscopic vision (either with a strobe light or LCD shutter glasses) on motion sickness while: (1) using visual field reversal, (2) reading while riding in a car (with or without external vision present), (3) making large pitch head movements during parabolic flight, (4) during exposure to rough seas in a small boat, and (5) seated and reading in the cabin area of a UH60 Black Hawk Helicopter during 20 min of provocative flight patterns.

Reschke, M. F.↗
NASA NTRS2007

V-Man Generation for 3-D Real Time Animation

The V-Man project has developed an intuitive authoring and intelligent system to create, animate, control and interact in real-time with a new generation of 3D virtual characters: The V-Men. It combines several innovative algorithms coming from Virtual Reality, Physical Simulation, Computer Vision, Robotics and Artificial Intelligence. Given a high-level task like "walk to that spot" or "get that object", a V-Man generates the complete animation required to accomplish the task. V-Men synthesise motion at runtime according to their environment, their task and their physical parameters, drawing upon its unique set of skills manufactured during the character creation. The key to the system is the automated creation of realistic V-Men, not requiring the expertise of an animator. It is based on real human data captured by 3D static and dynamic body scanners, which is then processed to generate firstly animatable body meshes, secondly 3D garments and finally skinned body meshes.

Nebel, Jean-Christophe↗
NASA NTRS2008

Presence Personalization and Persistence: A New Approach to Building Archives to Support Collaborative Research

We discuss approaches to building archives that support the way most science is done. Today research is done in formal teams and informal groups. However our on-line services are designed to work with a single user. We have begun prototyping a new approach to building archives in which support for collaborative research is built in from the start. We organize the discussion along three elements that we believe to be necessary for effective support: We must enable user presence in the archive environment; users must be able to interact. Users must be able to personalize the environment, adding data and capabilities useful to themselves and their team. These changes must be persistent: subsequent sessions must be able to build upon previous sessions. In building the archive we see the large multi-player interactive games as a paradigm of how this approach can work. These three 'P's are essential in gaming as well and we shall use insights from the gaming world and virtual reality systems like Second Life in our prototype.

McGlynn, Thomas A.↗
NASA NTRS2008

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G.↗
NASA NTRS2009

NASA Tech Briefs, February 2009

Tech Briefs are short announcements of innovations originating from research and development activities of the National Aeronautics and Space Administration. They emphasize information considered likely to be transferable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. Topics covered include: Measuring Low Concentrations of Liquid Water in Soil; The Mars Science Laboratory Touchdown Test Facility; Non-Contact Measurement of Density and Thickness Variation in Dielectric Materials; Compact Microwave Fourier Spectrum Analyzer; InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz; Combinatorial Generation of Test Suites; In-Phase Power-Combined Frequency Tripler at 300 GHz; Electronic System for Preventing Airport Runway Incursions; Smaller but Fully Functional Backshell for Cable Connector; Glove-Box or Desktop Virtual-Reality System; Composite Layer Manufacturing with Fewer Interruptions; Improved Photoresist Coating for Making CNT Field Emitters; A Simplified Diagnostic Method for Elastomer Bond Durability; Complex Multifunctional Polymer/Carbon-Nanotube Composites; Very High Output Thermoelectric Devices Based on ITO Nanocomposites; Reducing Unsteady Loads on a Piggyback Miniature Submarine; Ultrasonic/Sonic Anchor; Grooved Fuel Rings for Nuclear Thermal Rocket Engines; Pulsed Operation of an Ion Accelerator; Autonomous Instrument Placement for Mars Exploration Rovers; Mission and Assets Database; TCP/IP Interface for the Satellite Orbit Analysis Program (SOAP); Trajectory Calculator for Finite-Radius Cutter on a Lathe; Integrated System Health Management Development Toolkit.

Source record↗
NASA NTRS2008

Inertial Orientation Trackers with Drift Compensation

A class of inertial-sensor systems with drift compensation has been invented for use in measuring the orientations of human heads (and perhaps other, similarly sized objects). These systems can be designed to overcome some of the limitations of prior orientation-measuring systems that are based, variously, on magnetic, optical, mechanical-linkage, and acoustical principles. The orientation signals generated by the systems of this invention could be used for diverse purposes, including controlling head-orientation-dependent virtual reality visual displays or enabling persons whose limbs are paralyzed to control machinery by means of head motions. The inventive concept admits to variations too numerous to describe here, making it necessary to limit this description to a typical system, the selected aspects of which are illustrated in the figure. A set of sensors is mounted on a bracket on a band or a cap that gently but firmly grips the wearer s head to be tracked. Among the sensors are three drift-sensitive rotationrate sensors (e.g., integrated-circuit angular- rate-measuring gyroscopes), which put out DC voltages nominally proportional to the rates of rotation about their sensory axes. These sensors are mounted in mutually orthogonal orientations for measuring rates of rotation about the roll, pitch, and yaw axes of the wearer s head. The outputs of these rate sensors are conditioned and digitized, and the resulting data are fed to an integrator module implemented in software in a digital computer. In the integrator module, the angular-rate signals are jointly integrated by any of several established methods to obtain a set of angles that represent approximately the orientation of the head in an external, inertial coordinate system. Because some drift is always present as a component of an angular position computed by integrating the outputs of angular-rate sensors, the orientation signal is processed further in a drift-compensator software module.

Foxlin, Eric M.↗
NASA NTRS2009

Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects

Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs reviewed. DISCUSSION. A true ground-based flight analog for sensorimotor function is not feasible. A combination of flight analogs; however, can be used to selectively mimic different aspects of the spaceflight-induced sensorimotor performance decrements.

Taylor, Laura C.↗
NASA NTRS2010

Tactile Cueing as a Gravitational Substitute for Spatial Navigation During Parabolic Flight

INTRODUCTION: Spatial navigation requires an accurate awareness of orientation in your environment. The purpose of this experiment was to examine how spatial awareness was impaired with changing gravitational cues during parabolic flight, and the extent to which vibrotactile feedback of orientation could be used to help improve performance. METHODS: Six subjects were restrained in a chair tilted relative to the plane floor, and placed at random positions during the start of the microgravity phase. Subjects reported their orientation using verbal reports, and used a hand-held controller to point to a desired target location presented using a virtual reality video mask. This task was repeated with and without constant tactile cueing of "down" direction using a belt of 8 tactors placed around the mid-torso. Control measures were obtained during ground testing using both upright and tilted conditions. RESULTS: Perceptual estimates of orientation and pointing accuracy were impaired during microgravity or during rotation about an upright axis in 1g. The amount of error was proportional to the amount of chair displacement. Perceptual errors were reduced during movement about a tilted axis on earth. CONCLUSIONS: Reduced perceptual errors during tilts in 1g indicate the importance of otolith and somatosensory cues for maintaining spatial awareness. Tactile cueing may improve navigation in operational environments or clinical populations, providing a non-visual non-auditory feedback of orientation or desired direction heading.

Montgomery, K. L.↗
NASA NTRS2010

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G.↗
NASA NTRS2011

Designing a Distributed Space Systems Simulation in Accordance with the Simulation Interoperability Standards Organization (SISO)

Simulations are essential for engineering design. These virtual realities provide characteristic data to scientists and engineers in order to understand the details and complications of the desired mission. A standard development simulation package known as Trick is used in developing a source code to model a component (federate in HLA terms). The runtime executive is integrated into an HLA based distributed simulation. TrickHLA is used to extend a Trick simulation for a federation execution, develop a source code for communication between federates, as well as foster data input and output. The project incorporates international cooperation along with team collaboration. Interactions among federates occur throughout the simulation, thereby relying on simulation interoperability. Communication through the semester went on between participants to figure out how to create this data exchange. The NASA intern team is designing a Lunar Rover federate and a Lunar Shuttle federate. The Lunar Rover federate supports transportation across the lunar surface and is essential for fostering interactions with other federates on the lunar surface (Lunar Shuttle, Lunar Base Supply Depot and Mobile ISRU Plant) as well as transporting materials to the desired locations. The Lunar Shuttle federate transports materials to and from lunar orbit. Materials that it takes to the supply depot include fuel and cargo necessary to continue moon-base operations. This project analyzes modeling and simulation technologies as well as simulation interoperability. Each team from participating universities will work on and engineer their own federate(s) to participate in the SISO Spring 2011 Workshop SIW Smackdown in Boston, Massachusetts. This paper will focus on the Lunar Rover federate.

Cowen, Benjamin↗
NASA NTRS2005

Three-Dimensional Audio Client Library

The Three-Dimensional Audio Client Library (3DAudio library) is a group of software routines written to facilitate development of both stand-alone (audio only) and immersive virtual-reality application programs that utilize three-dimensional audio displays. The library is intended to enable the development of three-dimensional audio client application programs by use of a code base common to multiple audio server computers. The 3DAudio library calls vendor-specific audio client libraries and currently supports the AuSIM Gold-Server and Lake Huron audio servers. 3DAudio library routines contain common functions for (1) initiation and termination of a client/audio server session, (2) configuration-file input, (3) positioning functions, (4) coordinate transformations, (5) audio transport functions, (6) rendering functions, (7) debugging functions, and (8) event-list-sequencing functions. The 3DAudio software is written in the C++ programming language and currently operates under the Linux, IRIX, and Windows operating systems.

Rizzi, Stephen A.↗
NASA NTRS2004

Sensory-Feedback Exoskeletal Arm Controller

An electromechanical exoskeletal arm apparatus has been designed for use in controlling a remote robotic manipulator arm. The apparatus, called a force-feedback exoskeleton arm master (F-EAM) is comfortable to wear and easy to don and doff. It provides control signals from the wearer s arm to a robot arm or a computer simulator (e.g., a virtual-reality system); it also provides force and torque feedback from sensors on the robot arm or from the computer simulator to the wearer s arm. The F-EAM enables the wearer to make the robot arm gently touch objects and finely manipulate them without exerting excessive forces. The F-EAM features a lightweight design in which the motors and gear heads that generate force and torque feedback are made smaller than they ordinarily would be: this is achieved by driving the motors to power levels greater than would ordinarily be used in order to obtain higher torques, and by providing active liquid cooling of the motors to prevent overheating at the high drive levels. The F-EAM (see figure) includes an assembly that resembles a backpack and is worn like a backpack, plus an exoskeletal arm mechanism. The FEAM has five degrees of freedom (DOFs) that correspond to those of the human arm: 1. The first DOF is that of the side-to-side rotation of the upper arm about the shoulder (rotation about axis 1). The reflected torque for this DOF is provided by motor 1 via drum 1 and a planar four-bar linkage. 2. The second DOF is that of the up-and-down rotation of the arm about the shoulder. The reflected torque for this DOF is provided by motor 2 via drum 2. 3. The third DOF is that of twisting of the upper arm about its longitudinal axis. This DOF is implemented in a cable remote-center mechanism (CRCM). The reflected torque for this DOF is provided by motor 3, which drives the upper-arm cuff and the mechanism below it. A bladder inflatable by gas or liquid is placed between the cuff and the wearer s upper arm to compensate for misalignment between the exoskeletal mechanism and the shoulder. 4. The fourth DOF is that of flexion and extension of the elbow. The reflected torque for this DOF is provided by motor 4 and drum 4, which are mounted on a bracket that can slide longitudinally by a pin-and-slot engagement with the upper-arm cuff to compensate for slight variations in the position of the kinematic center of the elbow. Attached to drum 4 is an adapter plate to which is attached a CRCM for the lower arm. 5. The lower-arm CRCM implements the fifth DOF, which is the twist of the forearm about its longitudinal axis. Motor 5 provides the reflected torque for this DOF by driving the lower-arm cuff. A rod transmits twist and torsion between the lower-arm cuff and the hand cuff. With this system, the motion of the wearer s joints and the reflected torques applied to these joints can be measured and controlled in a relatively simple manner. This is because the anthropomorphic design of the mechanism imitates the kinematics of the human arm, eliminating the need for kinematic conversion of joint-torque and joint-angle data.

An, Bin↗
NASA NTRS2011

Technology Development to Support Human Health and Performance in Exploration Beyond Low Earth Orbit

In the course of defining the level of risks and mitigating the risks for exploration missions beyond low Earth orbit, NASA s Human Research Program (HRP) has identified the need for technology development in several areas. Long duration missions increase the risk of serious medical conditions due to limited options for return to Earth; no resupply; highly limited mass, power, volume; and communication delays. New space flight compatible medical capabilities required include: diagnostic imaging, oxygen concentrator, ventilator, laboratory analysis (saliva, blood, urine), kidney stone diagnosis & treatment, IV solution preparation and delivery. Maintenance of behavioral health in such an isolated, confined and extreme environment requires new sensory stimulation (e.g., virtual reality) technology. Unobtrusive monitoring of behavioral health and treatment methods are also required. Prolonged exposure to weightlessness deconditions bone, muscle, and the cardiovascular system. Novel exercise equipment or artificial gravity are necessary to prevent deconditioning. Monitoring of the degree of deconditioning is required to ensure that countermeasures are effective. New technologies are required in all the habitable volumes (e.g., suit, capsule, habitat, exploration vehicle, lander) to provide an adequate food system, and to meet human environmental standards for air, water, and surface contamination. Communication delays require the crew to be more autonomous. Onboard decision support tools that assist crew with real-time detection and diagnosis of vehicle and habitat operational anomalies will enable greater autonomy. Multi-use shield systems are required to provide shielding from solar particle events. The HRP is pursuing the development of these technologies in laboratories, flight analog environments and the ISS so that the human health and performance risks will be acceptable with the available resources.

Kundrot, C.E.↗
NASA NTRS2011

Spacecraft Guidance, Navigation, and Control Visualization Tool

G-View is a 3D visualization tool for supporting spacecraft guidance, navigation, and control (GN&C) simulations relevant to small-body exploration and sampling (see figure). The tool is developed in MATLAB using Virtual Reality Toolbox and provides users with the ability to visualize the behavior of their simulations, regardless of which programming language (or machine) is used to generate simulation results. The only requirement is that multi-body simulation data is generated and placed in the proper format before applying G-View.

Mandic, Milan↗
NASA NTRS2004

Latency Requirements for Head-Worn Display S/EVS Applications

NASA s Aviation Safety Program, Synthetic Vision Systems Project is conducting research in advanced flight deck concepts, such as Synthetic/Enhanced Vision Systems (S/EVS), for commercial and business aircraft. An emerging thrust in this activity is the development of spatially-integrated, large field-of-regard information display systems. Head-worn or helmet-mounted display systems are being proposed as one method in which to meet this objective. System delays or latencies inherent to spatially-integrated, head-worn displays critically influence the display utility, usability, and acceptability. Research results from three different, yet similar technical areas flight control, flight simulation, and virtual reality are collectively assembled in this paper to create a global perspective of delay or latency effects in head-worn or helmet-mounted display systems. Consistent definitions and measurement techniques are proposed herein for universal application and latency requirements for Head-Worn Display S/EVS applications are drafted. Future research areas are defined.

Bailey, Randall E.↗