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At least 127 records · Page 7

Wissler Simulations of a Liquid Cooled and Ventilation Garment (LCVG) for Extravehicular Activity (EVA)

In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series off tubes through which cooling water is circulated. To better predict the effectiveness of the LCG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained. Currently, increasing the fabric s thermal conductivity along with also examining an increase in the cooling tube conductivity to more efficiently remove the excess heat generated during EVA is being simulated. Initial trials varied cooling water temperature, water flow rate, garment conductivity, tube conductivity, and total number of cooling tubes in the LCVG. Results indicate that the total number of cooling tubes could be reduced to 22 and still achieve the desired heat removal rate of 361 W. Further improvements are being made to the garment network used in the model to account for temperature gradients associated with the spacing of the cooling tubes over the surface of the garment

Kesterson, Matthew↗

The Importance of HRA in Human Space Flight: Understanding the Risks

Human performance is critical to crew safety during space missions. Humans interact with hardware and software during ground processing, normal flight, and in response to events. Human interactions with hardware and software can cause Loss of Crew and/or Vehicle (LOCV) through improper actions, or may prevent LOCV through recovery and control actions. Humans have the ability to deal with complex situations and system interactions beyond the capability of machines. Human Reliability Analysis (HRA) is a method used to qualitatively and quantitatively assess the occurrence of human failures that affect availability and reliability of complex systems. Modeling human actions with their corresponding failure probabilities in a Probabilistic Risk Assessment (PRA) provides a more complete picture of system risks and risk contributions. A high-quality HRA can provide valuable information on potential areas for improvement, including training, procedures, human interfaces design, and the need for automation. Modeling human error has always been a challenge in part because performance data is not always readily available. For spaceflight, the challenge is amplified not only because of the small number of participants and limited amount of performance data available, but also due to the lack of definition of the unique factors influencing human performance in space. These factors, called performance shaping factors in HRA terminology, are used in HRA techniques to modify basic human error probabilities in order to capture the context of an analyzed task. Many of the human error modeling techniques were developed within the context of nuclear power plants and therefore the methodologies do not address spaceflight factors such as the effects of microgravity and longer duration missions. This presentation will describe the types of human error risks which have shown up as risk drivers in the Shuttle PRA which may be applicable to commercial space flight. As with other large PRAs of complex machines, human error in the Shuttle PRA proved to be an important contributor (~12 percent) to LOCV. An existing HRA technique was adapted for use in the Shuttle PRA, but additional guidance and improvements are needed to make the HRA task in space-related PRAs easier and more accurate. Therefore, this presentation will also outline plans for expanding current HRA methodology to more explicitly cover spaceflight performance shaping factors.

Hamlin, Teri↗

Habitat Design Considerations for Implementing Solar Particle Event Radiation Protection

Radiation protection is an important habitat design consideration for human exploration missions beyond Low Earth Orbit. Fortunately, radiation shelter concepts can effectively reduce astronaut exposure for the relatively low proton energies of solar particle events, enabling moderate duration missions of several months before astronaut exposure (galactic cosmic ray and solar particle event) approaches radiation exposure limits. In order to minimize habitat mass for increasingly challenging missions, design of radiation shelters must minimize dedicated, single-purpose shielding mass by leveraging the design and placement of habitat subsystems, accommodations, and consumables. NASA's Advanced Exploration Systems RadWorks Storm Shelter Team has recently designed and performed radiation analysis on several low dedicated mass shelter concepts for a year-long mission. This paper describes habitat design considerations identified during the study's radiation analysis. These considerations include placement of the shelter within a habitat for improved protection, integration of human factors guidance for sizing shelters, identification of potential opportunities for habitat subsystems to compromise on individual subsystem performances for overall vehicle mass reductions, and pre-configuration of shelter components for reduced deployment times.

Simon, Mathew A.↗

NASA-ONERA Collaboration on Human Factors in Aviation Accidents and Incidents

This is the first annual report jointly prepared by NASA and ONERA on the work performed under the agreement to collaborate on a study of the human factors entailed in aviation accidents and incidents, particularly focused on the consequences of decreases in human performance associated with fatigue. The objective of this agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight-crew fatigue factors whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and ONERA are collaborating on the development and assessment of automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases; much larger than can be handled practically by human experts.

Srivastava, Ashok N.↗

First Annual Report: NASA-ONERA Collaboration on Human Factors in Aviation Accidents and Incidents

This is the first annual report jointly prepared by NASA and ONERA on the work performed under the agreement to collaborate on a study of the human factors entailed in aviation accidents and incidents particularly focused on consequences of decreases in human performance associated with fatigue. The objective of this Agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight-crew fatigue factors whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and ONERA are collaborating on the development and assessment of automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases much larger than can be handled practically by human experts. This report presents the approach that is currently expected to be used in processing and analyzing the data for identifying decrements in aircraft performance and examining their relationships to decrements in crewmember performance due to fatigue. The decisions on the approach were based on samples of both the numerical and textual data that will be collected during the four studies planned under the Human Factors Monitoring Program (HFMP). Results of preliminary analyses of these sample data are presented in this report.

Srivastava, Ashok↗

Overtraining and exercise motivation: A research prospectus

The problems of exercise overtraining has recently become one of great interest to professionals in the field of human performance assessment. Quite obviously, the ultimate goal of the training process is to improve physical performance. However, excessive training can result in the opposite effect, that is, a performance decline and an impairment in the functional work capacity of the body. Research indicates that both psychological as well as physiological disturbances are quite common in overtrained individuals. For example, psychological changes include increased levels of depression, fatigue, and a lack of motivation. Similarly, impairment of the physiological function of the cardiovascular, metabolic, and endocrine systems also have been found. Some similarities may be found in the psychological and physiological states of crew members exposed to extended space flight and overtrained individuals. Therefore, the possibility exists that the crew members subjected to extended missions in space may develop overstressed or overtrained or both states during their flights. If such states do develop within the crew members, mission performance may be impaired. With these points as a background, the intent is to address potential research directions that NASA may consider viable and of a mutual interest to the researcher. A clear framework by which to begin discussion of research topics is needed; therefore, working definitions of overtraining and exercise motivation are presented. Subsequently, a proposed conceptional model of how exercise overtraining and motivation interact is presented. In support of the proposed model is a brief literature review of relevant areas. Potential research projects are presented and discussed.

Hackney, Anthony C.↗

Attention in a multi-task environment

Two experiments used a low fidelity multi-task simulation to investigate the effects of cue specificity on task preparation and performance. Subjects performed a continuous compensatory tracking task and were periodically prompted to perform one of several concurrent secondary tasks. The results provide strong evidence that subjects enacted a strategy to actively divert resources towards secondary task preparation only when they had specific information about an upcoming task to be performed. However, this strategy was not as much affected by the type of task cued (Experiment 1) or its difficulty level (Experiment 2). Overall, subjects seemed aware of both the costs (degraded primary task tracking) and benefits (improved secondary task performance) of cue information. Implications of the present results for computational human performance/workload models are discussed.

Andre, Anthony D.↗

Improving the computer-human interface: The qualitative monitor display

A technique for displaying the information needed by DSN operators for monitoring station performance is described. Known as a 'qualitative monitor,' it presents continuous variables in quasi-analog form on a digital cathode ray tube (CRT) display. Color changes, field reverses and blinking symbols assist the operator in identifying variables that are within acceptable limits and in performing corrective action when needed.

Baugh, H. W.↗

A practical ultrasonic plethysmograph

An ultrasonic plethysmograph, which gives improved performance over the standard Whitney Strain Gauge, is described. This instrument monitors dimension changes in human limbs by measuring the transit times of acoustic pulses across two chords of the limb. In the case of a small uniform expansion, the percentage change in limb volume is shown to be proportional to twice the percentage change in either of the measured chords. Measurement of two chords allows correction for possible non-uniform expansion. In addition, measurement of two chords allows an estimate of the absolute cross-sectional area of the limb. The developed instrument incorporates a microprocessor, which performs necessary calculation and control functions. Use of the microprocessor allows the instrument to be self-calibrating. In addition, the device can be easily reprogrammed to incorporate improvements in operating features or computational schemes.

Wu, V. C.↗

The Effect of Shared Information on Pilot/Controller And Controller/Controller Interactions

In order to respond to the increasing demand on limited airspace system resources, a number of applications of information technology have been proposed, or are under investigation, to improve the efficiency, capacity and reliability of ATM (Asynchronous Transfer Mode) operations. Much of the attention in advanced ATM technology has focused on advanced automation systems or decision aiding systems to improve the performance of individual Pilots or Controllers. However, the most significant overall potential for information technology appears to he in increasing the shared information between human agents such as Pilots, Controllers or between interacting Controllers or traffic flow managers. Examples of proposed shared information systems in the US include; Controller Pilot Databank Communication (CPDLC), Traffic Management Advisor (TMA); Automatic Dependent Surveillance (ADS); Collaborative Decision Making (CDM) and NAS Level Common Information Exchange. Air Traffic Management is fundamentally a human centered process consisting of the negotiation, execution and monitoring of contracts between human agents for the allocation of limited airspace, runway and airport surface resources. The decision processes within ATM tend to be Semistructured. Many of the routine elements in ATM decision making on the part of the Controllers or Pilots are well Structured and can be represented by well defined rules or procedures. However in disrupted conditions, the ATM decision processes are often Unstructured and cannot be reduced to a set of discrete rules. As a consequence, the ability to automate ATM processes will be limited and ATM will continue to be a human centric process where the responsibility and the authority for the negotiation will continue to rest with human Controllers and Pilots. The use of information technology to support the human decision process will therefore be an important aspect of ATM modernization. The premise of many of the proposed shared information systems is that the performance of ATM operations will improve with an increase in Shared Situation Awareness between agents (Pilots, Controller, Dispatchers). This will allow better informed control decisions and an improved ability to negotiate between agents. A common information basis may reduce communication load and may increase the level of collaboration in the decision process. In general, information sharing is expected to have advantages for all agents within the system. However there are important questions which remain to be,addressed. For example: What shared information is most important for developing effective Shared Situation Awareness? Are there issues of information saturation? Does information parity create ambiguity in control authority? Will information sharing induce undesirable or unstable gaming behavior between agents? This paper will explore the effect of current and proposed information sharing between different ATM agents. The paper will primarily concentrate on bilateral tactical interactions between specific agents (Pilot/Controller; Controller/Controller; Pilot/Dispatcher; Controller/Dispatcher) however it will also briefly discuss multilateral interaction and more strategic interactions.

Hansman, R. John↗

Relationship between alertness, performance, and body temperature in humans

Body temperature has been reported to influence human performance. Performance is reported to be better when body temperature is high/near its circadian peak and worse when body temperature is low/near its circadian minimum. We assessed whether this relationship between performance and body temperature reflects the regulation of both the internal biological timekeeping system and/or the influence of body temperature on performance independent of circadian phase. Fourteen subjects participated in a forced desynchrony protocol allowing assessment of the relationship between body temperature and performance while controlling for circadian phase and hours awake. Most neurobehavioral measures varied as a function of internal biological time and duration of wakefulness. A number of performance measures were better when body temperature was elevated, including working memory, subjective alertness, visual attention, and the slowest 10% of reaction times. These findings demonstrate that an increased body temperature, associated with and independent of internal biological time, is correlated with improved performance and alertness. These results support the hypothesis that body temperature modulates neurobehavioral function in humans.

Non-NASA Center↗

Incongruity, incongruity resolution, and mental states: The measure and modification of situational awareness and control

The research reported here describes the process of induction of various mental states. Our goals were to measure and to manipulate both the behavioral and the neurological correlates of particular mental states that have previously been demonstrated to be either beneficial or deleterious to in-flight performance situations. The experimental paradigm involved developing a context of which the participants were aware, followed by the introduction of an incongruity into that context. The empirical questions involved how the incongruity was resolved and the consequent effects on mental state. The dependent variables were measures of both the short-term ERP changes and the longer-term brain mapping indications of predominant mental states. The mission of NASA Flight Management Division and Human/Automation Integration Branch centers on the understanding and improvement of interaction between a complex system and a human operator. Specifically, the goal is improved efficiency through better operative procedures and control strategies. More efficient performance in demanding flight environments depends on improved situational awareness and replanning for fault management.

Derks, Peter L.↗

The Deep Space Network information system in the year 2000

The Deep Space Network (DSN), the largest, most sensitive scientific communications and radio navigation network in the world, is considered. Focus is made on the telemetry processing, monitor and control, and ground data transport architectures of the DSN ground information system envisioned for the year 2000. The telemetry architecture will be unified from the front-end area to the end user. It will provide highly automated monitor and control of the DSN, automated configuration of support activities, and a vastly improved human interface. Automated decision support systems will be in place for DSN resource management, performance analysis, fault diagnosis, and contingency management.

Markley, R. W.↗

Human Factors Considerations for Area Navigation Departure and Arrival Procedures

Area navigation (RNAV) procedures are being implemented in the United States and around the world as part of a transition to a performance-based navigation system. These procedures are providing significant benefits and have also caused some human factors issues to emerge. Under sponsorship from the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA) has undertaken a project to document RNAV-related human factors issues and propose areas for further consideration. The component focusing on RNAV Departure and Arrival Procedures involved discussions with expert users, a literature review, and a focused review of the NASA Aviation Safety Reporting System (ASRS) database. Issues were found to include aspects of air traffic control and airline procedures, aircraft systems, and procedure design. Major findings suggest the need for specific instrument procedure design guidelines that consider the effects of human performance. Ongoing industry and government activities to address air-ground communication terminology, design improvements, and chart-database commonality are strongly encouraged. A review of factors contributing to RNAV in-service errors would likely lead to improved system design and operational performance.

Barhydt, Richard↗

Emergency Locator Transmitter Survivability and Reliability Study

A comprehensive study of Emergency Locator Transmitter (ELT) performance was conducted over a three year period concluding in 2016 in support of the Search and Rescue (SAR) Mission Office at National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC). The study began with a review of reported performance cited in a collection of works published as early as 1980 as well as analysis of a focused set of contemporary aviation crash reports. Based on initial research findings, a series of subscale and fullscale system tests were performed at NASA Langley Research Center (LaRC) with the goals of investigating ELT system failure modes and developing recommended improvements to the Radio Technical Commission for Aeronautics (RTCA) Minimum Operational Performance Specification (MOPS) that will result in improved system performance. Enhanced performance of ELT systems in aviation accidents will reduce unnecessary loss of human life and make SAR operations safer and less costly by reducing the amount of time required to locate accident sites.

Stimson, Chad M.↗

NASA SPLICE Project: Development and Testing of Precision Landing GN&C Technologies

NASA's technology advancement needs for entry, descent and landing call for high-precision, high-rate sensors that can improve navigation accuracy and vehicle control performance. Higher landing accuracy is required for any future human lander missions, and likely, for most robotic missions 1,2. Sensors and algorithms that significantly reduce navigation errors and can image the local terrain will enable landing at locations of high scientific interest that would otherwise pose significant risk to the vehicle. The Safe and Precise Landing-Integrated Capabilities Evolution project, or SPLICE, is developing precision landing and hazard avoidance (PL&HA) technologies for NASA and for potential commercial space flight missions. SPLICE technologies include sensors, algorithms, advanced space flight computing capabilities, and simulation tools used to integrate and study guidance, navigation, and control (GN&C) system performance. SPLICE efforts include hardware-in-the-loop (HWIL) simulation testing, ground testing, and flight testing, including reuse of hardware from the CoOperative Blending of Autonomous Landing Technologies (COBALT) suborbital flight-test payload3,4. Two of the precise navigation sensors that are being developed and matured within SPLICE are LiDARs. Since 2006, NASA Langley has been developing a Navigation Doppler LiDAR (NDL) for precise velocity measurements, and SPLICE is building an NDL engineering test unit (ETU) that will be brought up to TRL 6 following environmental and high-speed1,2 testing. NASA Goddard is developing a Hazard Detection LiDAR (HD LiDAR) engineering development unit (EDU) for SPLICE that has relevance to future human and robotic lander missions. The HD LiDAR will be flight test and matured to TRL 5.

Restrepo, Carolina I.↗

Advancing Robotic Control for Space Exploration Using Robonaut 2

Robonaut 2, or R2, arrived on the International Space Station (ISS) in February 2011 and is currently being tested in preparation for its role initially as an Intra-Vehicular Activity (IVA) tool and eventually as a robot that performs Extra-Vehicular Activities (EVA). Robonaut 2, is a state of the art dexterous anthropomorphic robotic torso designed for assisting astronauts. R2 features increased force sensing, greater range of motion, higher bandwidth, and improved dexterity over its predecessor. Robonaut 2 is unique in its ability to safely allow humans in its workspace and to perform significant tasks in a workspace designed for humans. The current operational paradigm involves either the crew or the ground control team running semi-autonomous scripts on the robot as both the astronaut and the ground team monitor R2 and the data it produces. While this is appropriate for the check-out phase of operations, the future plans for R2 will stress the current operational framework. The approach described here will outline a suite of operational modes that will be developed for Robonaut 2. These operational modes include teleoperation, shared control, directed autonomy, and supervised autonomy, and they cover a spectrum of human involvement in controlling R2.

Badger, Julia↗