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  • Publication Date: 2017-03-06
    Description: Abstract
    Description: This dataset contains supplementary data concerning the SELASOMA project (GIPP-Project: Madagaskar; ID: 201204; FDSN-network code: ZE): (1) For stations with Cube data loggers, the raw data files are included. (2) For stations with EDL data loggers the log and auxiliary files are included. The main purpose of this dataset is to archive raw information on the timing quality, and to allow future use of alternative Cube-to-miniseed converters. Do not use this dataset if you are interested in continuous or event-based waveform data. Instead, refer to related dataset containing continuous waveforms . The dataset contains 1) log files for the stations with EDL data loggers (organized in sub-directories according to time range and station code); 2) separated MSEED-formatted data affected by some problems (organized in sub-directories according to time range and station code) and 3) raw CUBE-formatted data (organized in sub-directories according to time range and station name).
    Keywords: Seismology
    Language: English
    Type: Dataset , Dataset
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  • Publication Date: 2017-06-02
    Description: The diversity of fusaria in symptomatic Citrus trees in Greece, Italy and Spain was evaluated using morphological and molecular multi-locus analyses based on fragments of the calmodulin (CAM), intergenic spacer region of the rDNA (IGS), internal transcribed spacer region of the rDNA (ITS), large subunit of the rDNA (LSU), RNA polymerase largest subunit (RPB1), RNA polymerase second largest subunit (RPB2), translation elongation factor 1-alpha (EF-1α) and beta-tubulin (TUB) genes. A total of 11 species (six Fusarium spp., and five Neocosmospora spp.) were isolated from dry root rot, crown, trunk or twig canker or twig dieback of citrus trees. The most commonly isolated species were Fusarium sarcochroum, F. oxysporum and Neocosmospora solani. Three new Fusarium species are described, i.e., F. citricola and F. salinense belonging to the newly described F. citricola species complex; and F. siculi belonging to the F. fujikuroi species complex. Results of pathogenicity tests showed this new complex to include prominent canker causing agents affecting several Citrus spp. In addition, two new species are described in Neocosmospora, named N. croci and N. macrospora, the latter species being clearly differentiated from most members of this genus by producing large, up to nine-septate sporodochial conidia.
    Keywords: Citrus canker ; citrus dieback ; morphology ; multigene phylogeny ; systematics
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2017-06-15
    Description: Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.
    Keywords: Spacecraft Design, Testing and Performance
    Type: JSC-CN-39663-2 , AIAA Guidance, Navigation, and Control Conference (GN&C); 8-12 Jan. 2018; Kissimmee, FL; United States
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  • Publication Date: 2017-06-20
    Description: Optical navigation of human spacecraft was proposed on Gemini and implemented successfully on Apollo as a means of autonomously operating the vehicle in the event of lost communication with controllers on Earth. It shares a history with the "method of lunar distances" that was used in the 18th century and gained some notoriety after its use by Captain James Cook during his 1768 Pacific voyage of the HMS Endeavor. The Orion emergency return system utilizing optical navigation has matured in design over the last several years, and is currently undergoing the final implementation and test phase in preparation for Exploration Mission 1 (EM-1) in 2019. The software development is being worked as a Government Furnished Equipment (GFE) project delivered as an application within the Core Flight Software of the Orion camera controller module. The mathematical formulation behind the initial ellipse fit in the image processing is detailed in Christian. The non-linear least squares refinement then follows the technique of Mortari as an estimation process of the planetary limb using the sigmoid function. The Orion optical navigation system uses a body fixed camera, a decision that was driven by mass and mechanism constraints. The general concept of operations involves a 2-hour pass once every 24 hours, with passes specifically placed before all maneuvers to supply accurate navigation information to guidance and targeting. The pass lengths are limited by thermal constraints on the vehicle since the OpNav attitude generally deviates from the thermally stable tail-to-sun attitude maintained during the rest of the orbit coast phase. Calibration is scheduled prior to every pass due to the unknown nature of thermal effects on the lens distortion and the mounting platform deformations between the camera and star trackers. The calibration technique is described in detail by Christian, et al. and simultaneously estimates the Brown-Conrady coefficients and the Star Tracker/Camera interlock angles. Accurate attitude information is provided by the star trackers during each pass. Figure 1 shows the various phases of lunar return navigation when the vehicle is in autonomous operation with lost ground communication. The midcourse maneuvers are placed to control the entry interface conditions to the desired corridor for safe landing. The general form of optical navigation on Orion is where still images of the Moon or Earth are processed to find the apparent angular diameter and centroid in the camera focal plane. This raw data is transformed into range and bearing angle measurements using planetary data and precise star tracker inertial attitude. The measurements are then sent to the main flight computer's Kalman filter to update the onboard state vector. The images are, of course, collected over an arc to converge the state and estimate velocity. The same basic technique was used by Apollo to satisfy loss-of-comm, but Apollo used manual crew sightings with a vehicle-integral sextant instead of autonomously processing optical imagery. The software development is past its Critical Design Review, and is progressing through test and certification for human rating. In support of this, a hardware-in-the-loop test rig was developed in the Johnson Space Center Electro-Optics Lab to exercise the OpNav system prior to integrated testing on the Orion vehicle. Figure 2 shows the rig, which the test team has dubbed OCILOT (Orion Camera In the Loop Optical Testbed). Analysis performed to date shows a delivery that satisfies an allowable entry corridor as shown in Figure 3.
    Keywords: Space Communications, Spacecraft Communications, Command and Tracking
    Type: JSC-CN-39678 , AIAA/AAS Space Flight Mechanics Meeting 2018; 8-12 Jan. 2018; Kissimmee, FL; United States
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  • Publication Date: 2017-06-28
    Description: When we send humans to search for life on other planets, we'll need to know what we brought with us versus what may already be there. To ensure our crewed systems meet planetary protection requirements-and to protect our science from human contamination-we'll need to assess whether microorganisms may be leaking or venting from our spacecraft. Microbial sample collection outside of a pressurized spacecraft is complicated by temperature extremes, low pressures that preclude the use of laboratory standard (wetted) swabs, and operation either in bulky spacesuits or with robotic assistance. Engineers at the National Aeronautics and Space Administration (NASA) recently developed a swab kit for use in collecting microbial samples from the external surfaces of crewed spacecraft, including spacesuits. The Extravehicular Activity (EVA) Swab Kit consists of a single swab tool handle and an eight-canister sample caddy. The design team minimized development cost by re-purposing a heritage Space Shuttle tile repair handle that was designed to quickly snap into different tool attachments by engaging a mating device in each attachment. This allowed the tool handle to snap onto a fresh swab attachment much like popular shaving razor handles can snap onto a disposable blade cartridge. To disengage the handle from a swab, the user performs two independent functions, which can be done with a single hand. This dual operation mitigates the risk that a swab will be inadvertently released and lost in microgravity. Each swab attachment is fitted with commercially available foam swab tips, vendor-certified to be sterile for Deoxyribonucleic Acid (DNA). A microbial filter installed in the bottom of each sample container allows the container to outgas and repressurize without introducing microbial contaminants to internal void spaces. Extensive ground testing, post-test handling, and sample analysis confirmed the design is able to maintain sterile conditions as the canister moves between various pressure environments. To further minimize cost, the design team acquired extensive ground test experience in a relevant flight environment by piggy-backing onto suited crew training runs. These training runs allowed the project to validate tool interfaces with pressurized EVA gloves and collect user feedback on the tool design and function, as well as characterize baseline microbial data for different types of spacesuits. In general, test subjects found the EVA Swab Kit relatively straightforward to operate, but identified a number of design improvements that will be incorporated into the final design. Although originally intended to help characterize human forward contaminants, this tool has other potential applications, such as for collecting and preserving space-exposed materials to support astrobiology experiments.
    Keywords: Man/System Technology and Life Support ; Lunar and Planetary Science and Exploration
    Type: JSC-CN-39729 , IEEE Aerospace Conference; 3-10 Mar. 2018; Big Sky, MT; United States
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  • Publication Date: 2017-06-28
    Description: Early crewed Mars mission concepts developed by the National Aeronautics and Space Administration (NASA) assumed a single, large habitat would house six crew members for a 500-day Mars surface stay. At the end of the first mission, all surface equipment, including the habitat, -would be abandoned and the process would be repeated at a different Martian landing site. This work was documented in a series of NASA publications culminating with the Mars Design Reference Mission 5.0 (NASA-SP-2009-566). The Evolvable Mars Campaign (EMC) explored whether re-using surface equipment at a single landing site could be more affordable than the Apollo-style explore-abandon-repeat mission cadence. Initial EMC assumptions preserved the single, monolithic habitat, the only difference being a new requirement to reuse the surface habitat for multiple expedition crews. A trade study comparing a single large habitat versus smaller, modular habitats leaned towards the monolithic approach as more mass-efficient. More recent work has focused on the operational aspects of building up Mars surface infrastructure over multiple missions, and has identified compelling advantages of the modular approach that should be considered before making a final decision. This paper explores Mars surface mission operational concepts and integrated system analysis, and presents an argument for the modular habitat approach.
    Keywords: Man/System Technology and Life Support ; Lunar and Planetary Science and Exploration
    Type: JSC-CN-39761 , IEEE Aerospace Conference; 3-10 Mar. 2018; Big Sky, MT; United States
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  • Publication Date: 2017-07-12
    Description: The NASA Next Space Technologies for Exploration Partnerships (NextSTEP) program is a public-private partnership model that seeks commercial development of deep space exploration capabilities to support extensive human spaceflight missions around and beyond cislunar space. NASA first issued the Phase 1 NextSTEP Broad Agency Announcement to U.S. industries in 2014, which called for innovative cislunar habitation concepts that leveraged commercialization plans for low Earth orbit. These habitats will be part of the Deep Space Gateway (DSG), the cislunar space station planned by NASA for construction in the 2020s. In 2016, Phase 2 of the NextSTEP program selected five commercial partners to develop ground prototypes. A team of NASA research engineers and subject matter experts have been tasked with developing the ground test protocol that will serve as the primary means by which these Phase 2 prototype habitats will be evaluated. Since 2008, this core test team has successfully conducted multiple spaceflight analog mission evaluations utilizing a consistent set of operational products, tools, methods, and metrics to enable the iterative development, testing, analysis, and validation of evolving exploration architectures, operations concepts, and vehicle designs. The purpose of implementing a similar evaluation process for the NextSTEP Phase 2 Habitation Concepts is to consistently evaluate the different commercial partner ground prototypes to provide data-driven, actionable recommendations for Phase 3.
    Keywords: Ground Support Systems and Facilities (Space) ; Spacecraft Design, Testing and Performance
    Type: JSC-CN-39874 , IEEE Aerospace Conference 2018; 3-10 Mar. 2018; Big Sky, MT; United States
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  • Publication Date: 2017-07-12
    Description: The Biologic Analog Science Associated with Lava Terrains (BASALT) project is a four-year program dedicated to iteratively designing, implementing, and evaluating concepts of operations (ConOps) and supporting capabilities to enable and enhance scientific exploration for future human Mars missions. The BASALT project has incorporated three field deployments during which real (non-simulated) biological and geochemical field science have been conducted at two high-fidelity Mars analog locations under simulated Mars mission conditions, including communication delays and data transmission limitations. BASALT's primary Science objective has been to extract basaltic samples for the purpose of investigating how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically altered basalt environments. Field sites include the active East Rift Zone on the Big Island of Hawai'i, reminiscent of early Mars when basaltic volcanism and interaction with water were widespread, and the dormant eastern Snake River Plain in Idaho, similar to present-day Mars where basaltic volcanism is rare and most evidence for volcano-driven hydrothermal activity is relict. BASALT's primary Science Operations objective has been to investigate exploration ConOps and capabilities that facilitate scientific return during human-robotic exploration under Mars mission constraints. Each field deployment has consisted of ten extravehicular activities (EVAs) on the volcanic flows in which crews of two extravehicular and two intravehicular crewmembers conducted the field science while communicating across time delay and under bandwidth constraints with an Earth-based Mission Support Center (MSC) comprised of expert scientists and operators. Communication latencies of 5 and 15 min one-way light time and low (0.512 Mb/s uplink, 1.54 Mb/s downlink) and high (5.0 Mb/s uplink, 10.0 Mb/s downlink) bandwidth conditions were evaluated. EVA crewmembers communicated with the MSC via voice and text messaging. They also provided scientific instrument data, still imagery, video streams from chest-mounted cameras, GPS location tracking information. The MSC monitored and reviewed incoming data from the field across delay and provided recommendations for pre-sampling and sampling tasks based on their collective expertise. The scientists used dynamic priority ranking lists, referred to as dynamic leaderboards, to track and rank candidate samples relative to one another and against the science objectives for the current EVA and the overall mission. Updates to the dynamic leaderboards throughout the EVA were relayed regularly to the IV crewmembers. The use of these leaderboards enabled the crew to track the dynamic nature of the MSC recommendations and helped minimize crew idle time (defined as time spent waiting for input from Earth during which no other productive tasks are being performed). EVA timelines were strategically designed to enable continuous (delayed) feedback from an Earth-based Science Team while simultaneously minimizing crew idle time. Such timelines are operationally advantageous, reducing transport costs by eliminating the need for crews to return to the same locations on multiple EVAs while still providing opportunities for recommendations from science experts on Earth, and scientifically advantageous by minimizing the potential for cross-contamination across sites. This paper will highlight the space-to-ground interaction results from the three BASALT field deployments, including planned versus actual EVA timeline data, ground assimilation times (defined as the amount of time available to the MSC to provide input to the crew), and idle time. Furthermore, we describe how these results vary under the different communication latency and bandwidth conditions. Together, these data will provide a basis for guiding and prioritizing capability development for future human exploration missions.
    Keywords: Space Sciences (General)
    Type: JSC-CN-39879 , IEEE Aerospace Conference 2018; 3-10 Mar. 2018; Big Sky, MT ; United States
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  • Publication Date: 2017-07-22
    Description: A key decision facing Mars mission designers is how to power a crewed surface field station. Unlike the solar-powered Mars Exploration Rovers (MER) that could retreat to a very low power state during a Martian dust storm, human Mars surface missions are estimated to need at least 15 kilowatts of electrical (kWe) power simply to maintain critical life support and spacecraft functions. 'Hotel' loads alone for a pressurized crew rover approach two kWe; driving requires another five kWe-well beyond what the Curiosity rovers Radioisotope Power System (RPS) was designed to deliver. Full operation of a four-crew Mars field station is estimated at about 40 kWe. Clearly, a crewed Mars field station will require a substantial and reliable power source, beyond the scale of robotic mission experience. This paper explores the applications for both fission and RPS nuclear options for Mars.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-39818 , IEEE Aerospace Conference; 3-10 Mar. 2018; Big Sky, MT; United States
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  • Description / Table of Contents: Introduction -- The rise of regulatory governance -- Theories of regulation -- Regulatory space and regulatory regimes -- Policy processes and the regulatory policy cycle -- Bad, better and legitimate regulation -- Define: agenda-setting, issue diagnosis and objective setting -- Design: regime variables; option generation -- Decide: regime assessment and selection -- Implement: regime deployment, application and execution -- Evaluate: assessment of regulatory policy and regime -- The future of regulatory governance -- Conclusion
    Pages: xi, 288 Seiten , Illustrationen
    ISBN: 9781138935587 , 9781315677286 (electronic)
    Series Statement: Routledge critical studies in public management v.?
    Language: English
    Branch Library: IASS Library
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  • facet.materialart.
    Persoonia - Molecular Phylogeny and Evolution of Fungi (1878-9080) vol.38 (2017) p.20
    Publication Date: 2016-08-25
    Description: Anthracnose caused by Colletotrichum species is a serious disease of more than 30 plant genera. Several Colletotrichum species have been reported to infect chili in different countries. Although China is the largest chiliproducing country, little is known about the species that have been infecting chili locally. Therefore, we collected samples of diseased chili from 29 provinces of China, from which 1285 strains were isolated. The morphological characters of all strains were observed and compared, and multi-locus phylogenetic analyses (ITS, ACT, CAL, CHS-1, GAPDH, TUB2, and HIS3) were performed on selected representative strains. Fifteen Colletotrichum species were identified, with C. fioriniae, C. fructicola, C. gloeosporioides, C. scovillei, and C. truncatum being prevalent. Three new species, C. conoides, C. grossum, and C. liaoningense, were recognised and described in this paper. Colletotrichum aenigma, C. cliviae, C. endophytica, C. hymenocallidis, C. incanum, C. karstii, and C. viniferum were reported for the first time from chili. Pathogenicity of all species isolated from chili was confirmed, except for C. endophytica. The current study improves the understanding of species causing anthracnose on chili and provides useful information for the effective control of the disease in China.
    Keywords: DNA phylogeny ; multi-gene analysis ; plant pathogen ; systematics
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-08-25
    Description: Phialophora as defined by its type species P. verrucosa is a genus of Chaetothyriales, and a member of the group known as ‘black yeasts and relatives’. Phialophora verrucosa has been reported from mutilating human infections such as chromoblastomycosis, disseminated phaeohyphomycosis and mycetoma, while morphologically similar fungi are rather commonly isolated from the environment. Phenotypes are insufficient for correct species identification, and molecular data have revealed significant genetic variation within the complex of species currently identified as P. verrucosa or P. americana. Multilocus analysis of 118 strains revealed the existence of five reproductively isolated species apparently having different infectious potentials. Strains of the sexual morph Capronia semiimmersa cluster within P. americana. The newly defined taxa differ markedly in their predilection for the human host.
    Keywords: Chaetothyriales ; chromoblastomycosis ; phaeohyphomycosis ; Phialophora ; phylogeny ; taxonomy
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-07-15
    Description: NASA Extreme Environment Mission Operations (NEEMO) is an underwater spaceflight analog that allows a true mission-like operational environment and uses buoyancy effects and added weight to simulate different gravity levels. A mission was undertaken in 2016, NEEMO 21. The mission was performed at the Aquarius undersea research habitat. During the mission, the effects of varying operations concepts on representative communication latencies associated with Mars missions were studied. Six subjects were weighed out to simulate near-zero or partial gravity and evaluated different operations concepts for integration and management of a simulated Earth-based science team (ST) to provide input and direction during exploration activities. Exploration traverses were planned in advance based on precursor data collected. Subjects completed science-related tasks including pre-sampling surveys and marine science-based sampling as a portion of their tasks on saturation dives up to 4 hours in duration that were to simulate extravehicular activity (EVA) on Mars. A one-way communication latency of 15 minutes between space and mission control was simulated throughout the missions. Objective data included task completion times, total EVA times, crew idle time, translation time, SBT assimilation time (defined as time available for ST to discuss data/imagery after it has been collected, in addition to the time taken to watch imagery and listen to audio streaming over latency). Subjective data included acceptability, simulation quality, capability assessment ratings, and comments. Results were collected and will be presented on the acceptability of the operations concepts studied and which capabilities are the most enabling/enhancing in the operations concept. Discussion is presented on the importance of designing EVA timelines to account for the length of the task, level of interaction with the ground that is required/desired, and communication latency.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-36634 , IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT ; United States
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  • Publication Date: 2016-07-13
    Description: Providing adequate washout of carbon dioxide (CO2) from within a space suit helmet is essential to maintaining a safe operating environment for astronauts using space suits. A valid and reliable method for quantification of inspired CO2 inside space suits is required to ensure the health and performance of suited crewmembers. With this objective, several different methods for measuring the concentration of CO2 in a space suit helmet were evaluated. A nasal cannula was compared with respirator style masks worn by suited test subjects, with air drawn into gas analyzers to measure the concentration of CO2 in the immediate vicinity of the mouth and nose. The respirator style masks, some being commercially available products and some novel designs, did not provide repeatable results based on initial pilot testing in three subjects. Based on the analysis of those studies, the decision was made to down-select to a commercially available nasal cannula as the primary sampling device to be used in follow-on testing in the MKIII (n = 8) and Z2 (n = 6) prototype space suits, with five subjects performing tests in both suits allowing for repeated measures comparisons. Subjects were tasked with achieving target metabolic rates of 293, 586, and 879 Watts (1000, 2000, and 3000 BTU/h) and at air supply flow rates of 3.4, 6.8, and 10.2 Am(sup 3)/hr. (2, 4, and 6 ACFM). Each test condition was performed twice; once with subjects instructed to breathe however they felt comfortable, and once with subjects instructed to breathe only through their nose. Inspired CO2 values were determined by the lowest points, or troughs, within each breath of the respiratory trace. This method provides multiple inspired CO2 samples at known metabolic rates for each test condition and provides a larger data set for analysis than possible through gross averaging of the minimum inspired CO2. Results indicate that reliable measures are achievable under both breathing conditions but that restricting subjects to breathing only through their nose provides for less variable CO2 measurements breath to breath, within +/- 66.7 Pa CO2 (+/- 0.5 mmHg) at a 95% confidence level than when breathing unrestricted, which resulted in +/- 173.3 Pa CO2 (+/- 1.3 mmHg) variability with 95% confidence. However, during normal operation of a space suit it is not realistic to enforce or monitor the breathing style of the crewmember and, although restricted breathing is reliable, it is not known whether measurement of inspired CO2 during nose-only breathing is valid for evaluation of a space suit washout. To verify that one or both of the breathing style nasal cannula sampling methods provide a valid inspired CO2 measurement, testing is planned in an environmental chamber during which the ambient CO2 concentration will be controlled. A nasal cannula will be worn by unsuited subjects and measurements will be taken under both restricted and unrestricted breathing conditions across a range of metabolic rates during which nasal cannula CO2 concentration measures will be compared against the ambient value.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-36598 , IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-07-13
    Description: Human exploration of Mars will involve both crewed and robotic systems. Many mission concepts involve the deployment and assembly of mission support assets prior to crew arrival on the surface. Some of these deployment and assembly activities will be performed autonomously while others will be performed using teleoperations. However, significant communications latencies between the Earth and Mars make teleoperations challenging. Alternatively, low latency teleoperations are possible from locations in Mars orbit like Mars' moons Phobos and Deimos. To explore these latency opportunities, NASA is conducting a series of studies to investigate the effects of latency on telerobotic deployment and assembly activities. These studies are being conducted in laboratory environments at NASA's Johnson Space Center (JSC), the Human Exploration Research Analog (HERA) at JSC and the NASA Extreme Environment Mission Operations (NEEMO) underwater habitat off the coast of Florida. The studies involve two human-in-the-loop interactive simulations developed by the NASA Exploration Systems Simulations (NExSyS) team at JSC. The first simulation investigates manipulation related activities while the second simulation investigates mobility related activities. The first simulation provides a simple real-time operator interface with displays and controls for a simulated 6 degree of freedom end effector. The initial version of the simulation uses a simple control mode to decouple the robotic kinematic constraints and a communications delay to model latency effects. This provides the basis for early testing with more detailed manipulation simulations planned for the future. Subjects are tested using five operating latencies that represent teleoperation conditions from local surface operations to orbital operations at Phobos, Deimos and ultimately high Martian orbit. Subject performance is measured and correlated with three distance-to-target zones of interest. Each zone represents a target distance ranging from beyond 10m in Zone 1, through 1 cm to contact in Zone 5 with a step size factor of 10. Collected data consists of both objective simulation data (time, distance, hand controller inputs, velocity) and subjective questionnaire data. The second simulation provides a simple real-time operator interface with displays and control of a simulated surface rover. The rover traverses a synthetic Mars-like terrain and must be maneuvered to avoid obstacles while progressing to its destination. Like the manipulator simulation, subjects are tested using five operating latencies that represent teleoperation conditions from local surface operations to orbital operations at Phobos, Deimos and ultimately high Martian orbit. The rover is also operated at three different traverse speeds to assess the correlation between latency and speed. Collected data consisted of both objective simulation data (time, distance, hand controller inputs, braking) and subjective questionnaire data. These studies are exploring relationships between task complexity, operating speeds, operator efficiencies, and communications latencies for low latency teleoperations in support of human planetary exploration. This paper presents early results from these studies along with the current observations and conclusions. These and planned future studies will help to inform NASA on the potential for low latency teleoperations to support human exploration of Mars and inform the design of robotic systems and exploration missions.
    Keywords: Ground Support Systems and Facilities (Space) ; Lunar and Planetary Science and Exploration
    Type: JSC-CN-36630 , IEEE Aerospace Conference 2017; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-04-19
    Description: NASA uses two HRA assessment methodologies. The first is a simplified method which is based on how much time is available to complete the action, with consideration included for environmental and personal factors that could influence the human's reliability. This method is expected to provide a conservative value or placeholder as a preliminary estimate. This preliminary estimate is used to determine which placeholder needs a more detailed assessment. The second methodology is used to develop a more detailed human reliability assessment on the performance of critical human actions. This assessment needs to consider more than the time available, this would include factors such as: the importance of the action, the context, environmental factors, potential human stresses, previous experience, training, physical design interfaces, available procedures/checklists and internal human stresses. The more detailed assessment is still expected to be more realistic than that based primarily on time available. When performing an HRA on a system or process that has an operational history, we have information specific to the task based on this history and experience. In the case of a PRA model that is based on a new design and has no operational history, providing a "reasonable" assessment of potential crew actions becomes more problematic. In order to determine what is expected of future operational parameters, the experience from individuals who had relevant experience and were familiar with the system and process previously implemented by NASA was used to provide the "best" available data. Personnel from Flight Operations, Flight Directors, Launch Test Directors, Control Room Console Operators and Astronauts were all interviewed to provide a comprehensive picture of previous NASA operations. Verification of the assumptions and expectations expressed in the assessments will be needed when the procedures, flight rules and operational requirements are developed and then finalized.
    Keywords: Quality Assurance and Reliability
    Type: JSC-CN-36101 , Annual Reliability and Maintainability Symposium; 23-26 Jan. 2017; Orlando, FL; United States
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  • Publication Date: 2016-07-26
    Description: Unstructured grid solvers have well-known issues predicting surface heat fluxes when strong shocks are present. Various efforts have been made to address the underlying numerical issues that cause the erroneous predictions. The present work addresses some of the shortcomings of unstructured grid solvers, not by addressing the numerics, but by applying structured grid best practices to unstructured grids. A methodology for robust shock detection and shock fitting is outlined and applied to production relevant cases. Results achieved by using the Loci-CHEM Computational Fluid Dynamics solver are provided.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JSC-CN-36483 , AIAA SciTech 2017; 9-13 Jan. 2017; Grapevine, TX; United States
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  • Publication Date: 2016-07-01
    Description: NASA's human space program has developed considerable experience with near Earth space operations. Although NASA has experience with deep space robotic missions, NASA has little substantive experience with human deep space operations. Even in the Apollo program, the missions lasted only a few weeks and the communication latencies were on the order of seconds. Human missions beyond the relatively close confines of the Earth-Moon system will involve missions with durations measured in months and communications latencies measured in minutes. To minimize crew risk and to maximize mission success, NASA needs to develop a better understanding of the implications of these types of mission durations and communication latencies on vehicle design, mission design and flight controller interaction with the crew. To begin to address these needs, NASA performed a study using a physics-based subsystem simulation to investigate the interactions between spacecraft crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation, built with a subsystem modeling tool developed at NASA's Johnson Space Center, models the life support system of a Mars transit vehicle. The simulation contains models of the cabin atmosphere and pressure control system, electrical power system, drinking and waste water systems, internal and external thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the vehicle subsystems; 2) a mission control center interface with data transport delays up to 15 minutes each way; 3) a real-time simulation test conductor interface that can be use to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission between July 18th and Aug 3rd of year 2016. The NEEMO mission provides ideal conditions for this study with crew in the loop, an active control center, and real-time flow of high latency communications and data. NEEMO crew and ground support will work through procedures including activation of the transit vehicle power system, opening the hatch between the transit vehicle and a Mars ascent vehicle, transferring simulated crewmembers between vehicles, overcoming subsystem malfunctions, sending simulated crewmember on extra-vehicular activities, and other housekeeping activities. This study is enhancing the understanding of high latency operations and the advantages and disadvantages of different communication methods. It is also providing results that will help improve the design of simulation interfaces and inform the design of Mars transit vehicles.
    Keywords: Ground Support Systems and Facilities (Space) ; Space Communications, Spacecraft Communications, Command and Tracking
    Type: JSC-CN-36600 , IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-07-01
    Description: An over-arching goal of the multi-year Biologic Analog Science Associated with Lava Terrains (BASALT) project is to iteratively develop, implement, and evaluate concepts of operations (ConOps) and supporting capabilities intended to enable and enhance human exploration of Mars. Geological and biological scientific fieldwork is being conducted during four total deployments at two high-fidelity Mars analogs, all within simulated Mars mission conditions that are based on current architectural assumptions for Mars exploration missions. Specific capabilities being evaluated include the use of mobile science platforms, extravehicular informatics, communication and navigation packages, advanced science mission planning tools, and scientifically-relevant instrument packages to achieve the project goals. This paper describes the planning, execution, and results of the first field deployment, referred to as BASALT 1, which consisted of a series of 12 simulated extravehicular activities (EVAs) on the lava terrains of Craters of the Moon, Idaho. Scientific objectives of the EVAs related to determination of how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically-altered basalt environments. The concept of operations (ConOps) and capabilities deployed and tested during BASALT 1 were based on extensive data from previous NASA trade studies and analog testing, and the primary research question was whether those ConOps and capabilities would work acceptably when performing real (non-simulated) biological and geological scientific exploration under four different communication scenarios. Specifically, communication latencies of 5 and 15 minutes one-way light time (OWLT) were tested; these delays fall within the range of 4 to 22 minute OWLT delays that would be experienced during a Mars mission. Science operations were also conducted under low bandwidth conditions (0.512 Mb/s uplink, 1.54 Mb/s downlink), representing a conservative and affordable flight data rate, and a higher bandwidth case (5.0 Mb/s uplink, 10.0 Mb/s downlink), representing an upgraded human mission capability that would require additional infrastructure and technology development. In all conditions, two EVA crewmembers communicated with two intravehicular (IV) crewmembers with high bandwidth and near-zero communication latency, simulating communication among crewmembers on Mars. EVA crewmembers wore simulated EVA informatics backpacks including communication systems, position tracking, hand-held field spectrometers, cameras, and sample collection tools. Bidirectional communication between crewmembers ("Mars") and a Mission Support Center ("Earth"), staffed by a team of science and operations experts, was subject to the aforementioned latency and bandwidth constraints. This paper presents the synthesized results of the BASALT 1 deployment with respect to ConOps and capabilities assessment. Evaluation of the ConOps and capabilities was accomplished through a combination of network analytical data, completion of scientific objectives, ethnographic observations, planned versus actual timeline data, and collection of subjective ratings and comments using the same methodology employed during multiple previous NASA analog tests. In addition to assessing the acceptability of the ConOps and capabilities from scientific and operational perspectives, the extent to which specific capabilities enabled or enhanced the science operations was also evaluated. These data will provide a basis for prioritization of capability development for future BASALT deployments and, ultimately, future human exploration missions.
    Keywords: Man/System Technology and Life Support ; Space Transportation and Safety
    Type: JSC-CN-36610 , IEEE Aerospace Conference 2017; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-06-15
    Description: In the proposed paper, the optimal design of reference strain structures (RSS) will be performed targeting for the accurate observation of the dynamic bending and torsion deformation of a flexible rocket. It will provide the detailed description of the finite-element (FE) model of a notional flexible rocket created in MSC.Patran. The RSS will be attached longitudinally along the side of the rocket and to track the deformation of the thin-walled structure under external loads. An integrated surrogate-based multi-objective optimization approach will be developed to find the optimal design of the RSS using the FE model. The Kriging method will be used to construct the surrogate model. For the data sampling and the performance evaluation, static/transient analyses will be performed with MSC.Natran/Patran. The multi-objective optimization will be solved with NSGA-II to minimize the difference between the strains of the launch vehicle and RSS. Finally, the performance of the optimal RSS will be evaluated by checking its strain-tracking capability in different numerical simulations of the flexible rocket.
    Keywords: Structural Mechanics ; Launch Vehicles and Launch Operations
    Type: KSC-E-DAA-TN32305 , AIAA SciTech Conference; 9-13 Jan. 2017; Grapevine, TX; United States
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  • Publication Date: 2016-06-09
    Description: Flying a mission in space requires a massive commitment of resources, and without the talent and commitment of the people involved in this effort we would never leave the atmosphere of Earth. When we use the phrase "humans in the loop", it could apply to almost any endeavor since everything starts with humans developing a concept, completing the design process, building or implementing a product and using the product to achieve a goal or purpose. Narrowing the focus to spaceflights, there are a variety of individuals involved throughout the preparations for flight and the flight itself. All of the humans involved add value and support for program success. The purpose of this paper focuses on how a Probabilistic Risk Assessment (PRA) accounts for the human in the loop for potential missions using a technique called Human Reliability Analysis (HRA). Human actions can increase or decrease the overall risk via initiating events or mitigating them, thus removing the human from the loop doesn't always lower the risk.
    Keywords: Quality Assurance and Reliability
    Type: JSC-CN-36503 , AIAA Science & Technology Forum & Exposition (SciTech 2017); 9-13 Jan. 2017; Grapevine, TX; United States
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  • Publication Date: 2016-08-18
    Description: One of the biggest challenges facing NASA's deep space exploration goals is structural mass. A long duration transit vehicle on a journey to Mars, for example, requires a large internal volume for cargo, supplies and crew support. As with all space structures, a large pressure vessel is not enough. The vehicle also requires thermal, micro-meteoroid, and radiation protection, a navigation and control system, a propulsion system, and a power system, etc. As vehicles get larger, their associated systems also get larger and more complex. These vehicles require larger lift capacities and force the mission to become extremely costly. In order to build large volume habitable vehicles, with only minimal increases in launch volume and mass, NASA is developing lightweight structures. Lightweight structures are made from non-metallic materials including graphite composites and high strength fabrics and could provide similar or better structural capability than metals, but with significant launch volume and mass savings. Fabric structures specifically, have been worked by NASA off and on since its inception, but most notably in the 1990's with the TransHAB program. These TransHAB developed structures use a layered material approach to form a pressure vessel with integrated thermal and micro-meteoroid and orbital debris (MMOD) protection. The flexible fabrics allow the vessel to be packed in a small volume during launch and expand into a much larger volume once in orbit. NASA and Bigelow Aerospace recently installed the first human-rated inflatable module on the International Space Station (ISS), known as the Bigelow Expandable Activity Module (BEAM) in May of 2016. The module provides a similar internal volume to that of an Orbital ATK Cygnus cargo vehicle, but with a 77% launch volume savings. As lightweight structures are developed, testing methods are vital to understanding their behavior and validating analytical models. Common techniques can be applied to fabric materials, such as tensile testing, fatigue testing, and shear testing, but common measurement techniques cannot be used on fabric. Measuring strain in a material and during a test is a critical parameter for an engineer to monitor the structure during the test and correlate to an analytical model. The ability to measure strain in fabric structures is a challenge for NASA. Foil strain gauges, for example, are commonplace on metallic structures testing, but are extremely difficult to interface with a fabric substrate. New strain measuring techniques need to be developed for use with fabric structures. This paper investigates options for measuring strain in fabric structures for both ground testing and in-space structural health monitoring. It evaluates current commercially available options and outlines development work underway to build custom measurement solutions for NASA's fabric structures.
    Keywords: Instrumentation and Photography
    Type: JSC-CN-36506 , AIAA SciTech; 9-13 Jan. 2017; Grapevine, TX; United States
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  • Publication Date: 2016-09-16
    Description: Infrageneric relations of the genetically diverse milkcap genus Lactifluus (Russulales, Basidiomycota) are poorly known. Currently used classification systems still largely reflect the traditional, mainly morphological, characters used for infrageneric delimitations of milkcaps. Increased sampling, combined with small-scale molecular studies, show that this genus is underexplored and in need of revision. For this study, we assembled an extensive dataset of the genus Lactifluus, comprising 80 % of all known species and 30 % of the type collections. To unravel the infrageneric relationships within this genus, we combined a multi-gene molecular phylogeny, based on nuclear ITS, LSU, RPB2 and RPB1, with a morphological study, focussing on five important characteristics (fruit body type, presence of a secondary velum, colour reaction of the latex/context, pileipellis type and presence of true cystidia). Lactifluus comprises four supported subgenera, each containing several supported clades. With extensive sampling, ten new clades and at least 17 new species were discovered, which highlight the high diversity in this genus. The traditional infrageneric classification is only partly maintained and nomenclatural changes are proposed. Our morphological study shows that the five featured characteristics are important at different evolutionary levels, but further characteristics need to be studied to find morphological support for each clade. This study paves the way for a more detailed investigation of biogeographical history and character evolution within Lactifluus.
    Keywords: milkcaps ; molecular evolution ; morphology ; taxonomy
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-09-16
    Description: Based on molecular and morphological data we investigated the taxonomy and phylogeny of the ectomycorrhizal genus Tricholoma in northern Europe. Our phylogenetic tree confirmed the presence of at least 72 well circumscribed species within the region. Of these, three species, viz. T. boreosulphurescens, T. bryogenum and T. ilkkae are described as new to science, based on morphological, distributional, ecological and molecular data. Several other terminal branches represent putative cryptic taxa nested within classical species or species groups. Molecular type studies and/or designation of sequenced neotypes are needed in these groups, before the taxonomy can be settled. In general our phylogenetic analysis supported previous suprageneric classification systems, but with some substantial changes. Most notably, T. virgatum and allies were found to belong to sect. Tricholoma rather than sect. Atrosquamosa, while T. focale was found to be clearly nested in sect. Genuina rather than in sect. Caligata. In total, ten sections are accepted, with five species remaining unassigned. The combination of morphological and molecular data showed pileus colour, pileipellis structure, presence of clamp connections and spore size to be rather conservative characters within accepted sections, while the presence of a distinct ring, and especially host selection were highly variable within these.
    Keywords: Agarics ; biogeography ; cryptic species ; ectomycorrhizal fungi ; host selection ; morphological traits ; phylogeny ; Tricholomataceae
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-09-17
    Description: The astronaut community is unique, and may be disproportionately exposed to occupational hazards not commonly seen in other communities. The extent to which the demands of the astronaut occupation and exposure to spaceflight-related hazards affect the health of the astronaut population over the life course is not completely known. A better understanding of the individual, population, and mission impacts of astronaut occupational exposures is critical to providing clinical care, targeting occupational surveillance efforts, and planning for future space exploration. The ability to characterize the risk of latent health conditions is a significant component of this understanding. Provision of health screening services to active and former astronauts ensures individual, mission, and community health and safety. Currently, the NASA-Johnson Space Center (JSC) Flight Medicine Clinic (FMC) provides extensive medical monitoring to active astronauts throughout their careers. Upon retirement, astronauts may voluntarily return to the JSC FMC for an annual preventive exam. However, current retiree monitoring includes only selected screening tests, representing an opportunity for augmentation. The potential long-term health effects of spaceflight demand an expanded framework of testing for former astronauts. The need is two-fold: screening tests widely recommended for other aging populations are necessary to rule out conditions resulting from the natural aging process (e.g., colonoscopy, mammography); and expanded monitoring will increase NASA's ability to better characterize conditions resulting from astronaut occupational exposures. To meet this need, NASA has begun an extensive exploration of the overall approach, cost, and policy implications of e an Astronaut Occupational Health program to include expanded medical monitoring of former NASA astronauts. Increasing the breadth of monitoring services will ultimately enrich the existing evidence base of occupational health risks to astronauts. Such an expansion would therefore improve the understanding of the health of the astronaut population as a whole, and the ability to identify, mitigate, and manage such risks in preparation for deep space exploration missions.
    Keywords: Aerospace Medicine ; Life Sciences (General)
    Type: JSC-CN-37271 , International Conference on Occupational Health and Safety (ICOHS 2017); 9-10 Mar. 2017; Miami, FL; United States
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  • Publication Date: 2016-09-23
    Description: This paper presents the design and development of a friction-based coupling device for a fiber-optic monitoring system that can be deployed on existing subsea structures. This paper provides a summary of the design concept, prototype development, prototype performance testing, and design refinements of the device. The results of the laboratory testing of the first prototype performed at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) are included in this paper. Limitations of the initial design were identified and future design improvements were proposed. These new features will enhance the coupling of the device and improve the monitoring system measurement capabilities. A major challenge of a post-installed instrumentation monitoring system is to ensure adequate coupling between the instruments and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome coupling limitations caused by marine growth and soil contamination on subsea structures, flowlines or risers. The work described in this paper investigates the design of a friction-based coupling device (friction clamp), which is applicable for pipelines and structures that are suspended in the water column and those that are resting on the seabed. The monitoring elements consist of fiber-optic sensors that are bonded to a metal clamshell with a high-friction coating. The friction clamp has a single hinge design to facilitate the operation of the clamp and dual rows of opposing fasteners to distribute the clamping force on the structure. The friction clamp can be installed by divers in shallow depths or by remotely operated vehicles in deep-water applications. NASA-JSC was involved in the selection and testing of the friction coating, and in the design and testing of the prototype clamp device. Four-inch diameter and eight-inch diameter sub-scale friction clamp prototypes were built and tested to evaluate the strain measuring capabilities of the design under different loading scenarios. The testing revealed some limitations of the initial design concept, and subsequent refinements were explored to improve the measurement performance of the system. This study was part of a collaboration between NASA-JSC and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries.
    Keywords: Mechanical Engineering
    Type: JSC-CN-37503 , International Conference on Ocean Offshore & Artic Engineering (OMAE); 25-30 Jun. 2017; Trondheim; Norway
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  • Publication Date: 2016-09-28
    Description: INTRODUCTION: The increase in the alveolar-arterial oxygen (O2) partial pressure gradient during increasing hypoxia may further increase in microgravity (microG). METHODS: Four male astronauts on STS-69 (1995) and 4 on STS-72 (1996) submitted to an acute sequential hypoxic challenge by breathing for 4 minutes at 18.0%, 14.9%, 13.5%, 12.9%, and 12.2% O2 - balance nitrogen at sea level. The 18.0% O2 mixture was equivalent to an inspired O2 partial pressure (PIO2) of 127 mm Hg when exposed to 527 mm Hg while breathing 26.5% O2 for several days in G. A Novametrix CO2SMO Model 7100 recorded heart rate (HR, beats min-1) and hemoglobin (Hb) O2 saturation through finger pulse oximetry (SpO2, %), end-tidal carbon dioxide partial pressure (PETCO2, mm Hg), and respiration rate (RR, breaths/min) through an infrared capnograph positioned in a mouthpiece. Measurements were also taken the day of return to Earth (R+0) and at R+2. Linear mixed effects models assessed changes in SpO2 after exposure to microG. Interactions between measurement condition and available physiologic measurements were also explored. RESULTS: Astronaut SpO2 levels at baseline, R+0, and R+2 were not significantly different from in flight, about 97% given a PIO2 of 127 mm Hg. There was no difference in astronaut SpO2 levels between baseline and R+0 or R+2 over the hypoxic challenge. Additionally, no significant interactions were identified. CONCLUSIONS: While microG did not affect astronaut Hb O2 saturation in this study, large within- and between-subject variability in SpO2 at increasingly hypoxic doses require a deeper understanding of subject-specific factors that influence O2 transfer onto Hb.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37563 , AsMA Annual Scientific Meeting ; 29 Apr. - 4 May 2017; Denver, CO; United States
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  • facet.materialart.
    Communications in Nonlinear Science and Numerical Simulation
    Publication Date: 2016-10-06
    Description: We study synchronization properties of three nonlinearly coupled chaotic maps. Coupling is introduced in such a way, that it cannot be reduced to pairwise terms, but includes combined action of all interacting units. For two models of nonlinear coupling we characterize the transition to complete synchrony, as well as partially synchronized states. Relation to hypernetworks of chaotic units is also discussed.
    Language: English
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
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  • Publication Date: 2016-10-05
    Description: Management guidelines were created to screen and manage asymptomatic renal stones in U.S. astronauts. The true risk for renal stone formation in astronauts due to the space flight environment is unknown. Proper management of this condition is crucial to mitigate health and mission risks. The NASA Flight Medicine Clinic electronic medical record and the Lifetime Surveillance of Astronaut Health databases were reviewed. An extensive review of the literature and current aeromedical standards for the monitoring and management of renal stones was also done. This work was used to develop a screening and management protocol for renal stones in astronauts that is relevant to the spaceflight operational environment. In the proposed guidelines all astronauts receive a yearly screening and post-flight renal ultrasound using a novel ultrasound protocol. The ultrasound protocol uses a combination of factors, including: size, position, shadow, twinkle and dispersion properties to confirm the presence of a renal calcification. For mission-assigned astronauts, any positive ultrasound study is followed by a low-dose renal computed tomography scan and urologic consult. Other specific guidelines were also created. A small asymptomatic renal stone within the renal collecting system may become symptomatic at any time, and therefore affect launch and flight schedules, or cause incapacitation during a mission. Astronauts in need of definitive care can be evacuated from the International Space Station, but for deep space missions evacuation is impossible. The new screening and management algorithm has been implemented and the initial round of screening ultrasounds is under way. Data from these exams will better define the incidence of renal stones in U.S. astronauts, and will be used to inform risk mitigation for both short and long duration spaceflights.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37560 , Aerospace Medical Association Scientific Meeting (AsMA); 29 Apr. - 4 May 2017; Denver, CO; United States
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  • Publication Date: 2016-10-05
    Description: No abstract available
    Keywords: Quality Assurance and Reliability
    Type: JSC-CN-37493-2 , RAMS 2014: The Annual Reliability and Maintainability Symposium ; 23-27 Jan 2017; Orlando, FL; United States
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  • Publication Date: 2016-10-05
    Description: NASA (National Aeronautics and Space Administration) Johnson Space Center (JSC) Safety and Mission Assurance (S&MA) uses two human reliability analysis (HRA) methodologies. The first is a simplified method which is based on how much time is available to complete the action, with consideration included for environmental and personal factors that could influence the human's reliability. This method is expected to provide a conservative value or placeholder as a preliminary estimate. This preliminary estimate or screening value is used to determine which placeholder needs a more detailed assessment. The second methodology is used to develop a more detailed human reliability assessment on the performance of critical human actions. This assessment needs to consider more than the time available, this would include factors such as: the importance of the action, the context, environmental factors, potential human stresses, previous experience, training, physical design interfaces, available procedures/checklists and internal human stresses. The more detailed assessment is expected to be more realistic than that based primarily on time available. When performing an HRA on a system or process that has an operational history, we have information specific to the task based on this history and experience. In the case of a Probabilistic Risk Assessment (PRA) that is based on a new design and has no operational history, providing a "reasonable" assessment of potential crew actions becomes more challenging. To determine what is expected of future operational parameters, the experience from individuals who had relevant experience and were familiar with the system and process previously implemented by NASA was used to provide the "best" available data. Personnel from Flight Operations, Flight Directors, Launch Test Directors, Control Room Console Operators, and Astronauts were all interviewed to provide a comprehensive picture of previous NASA operations. Verification of the assumptions and expectations expressed in the assessments will be needed when the procedures, flight rules, and operational requirements are developed and then finalized.
    Keywords: Quality Assurance and Reliability
    Type: JSC-CN-37493-1 , RAMS 2017: The Annual Reliability and Maintainability Symposium; 23-26 Jan. 2017; Orlando, FL; United States
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  • facet.materialart.
    Persoonia - Molecular Phylogeny and Evolution of Fungi (1878-9080) vol.38 (2017) p.81
    Publication Date: 2016-10-07
    Description: Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains studied revealed that they cluster in two main lineages. The first was associated with the genus Xenopenidiella whereas the other represented two ant-isolated lineages sister to the taxa Penidiella aggregata and P. drakensbergensis, which are allocated to the new genus Penidiellomyces. The genus Penidiella is limited to the lineage containing P. columbiana, which is not congeneric with Penidiellomyces or Penidiellopsis, nor with Simplicidiella, a novel genus introduced here to accommodate a strain isolated from ants. For species level analysis, the final 26 aligned sequences of the ITS (498 characters), cmdA (389 characters), tef1 (342 characters) and tub2 (446 characters) gene regions lead to the introduction of six new species in Xenopenidiella, and one in respectively Penidiellopsis and Simplicidiella. The species described in this study were distinguished by the combination of morphological and phylogenetic data. Novelties on the integument of leaf-cutting ants from Brazil include: Penidiellopsis ramosus, Xenopenidiella clavata, X. formica, X. inflata, X. laevigata, X. nigrescens, X. tarda spp. nov., and Simplicidiella nigra gen. & sp. nov. Beta-tubulin is recommended as primary barcode for the distinction of species in Penidiellopsis, whereas ITS was sufficient to distinguish species of Xenopenidiella.
    Keywords: Attini tribe ; leaf-cutting ants ; multi-gene analyses ; systematics ; Xenopenidiella
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-10-11
    Description: Erosion can be observed in many arable soil landscapes such as those of the hummocky ground moraine. The topsoil removal by water erosion in combination with tillage operations (e.g., ploughing) is leading to truncated soil profiles along slopes with reduced solum thickness and modified properties of soil horizons. The objectives were to identify and quantify effects of erosion-induced soil modifications on the water balance and the leaching of dissolved organic and inorganic carbon (DOC, DIC), considering complex soil-crop interactions. The idea was to compare lysimeter-based water and solute balances of eroded Luvisols that differed in solum depth. The six high precision weighing lysimeters (1.0 m2 surface, 1.5 m high; UMS Science-Lysimeter) had a resolution of 10 g (=0.01 mm). The cylindrical steel rings of the lysimeters were filled with undisturbed soil monoliths from two fields. Lysimeter soils were cultivated with maize, winter rye, Sudangrass, triticale, alfalfa, and Persian clover during the observation period April 2011 to March 2014. Cumulative drainage of the six lysimeter soils ranged from 57 for the least to 104 mm y−1 for the most eroded Luvisols; the differences of about 83% indicated that the erosional profile modifications in combination with differences in crop development affected the water balance components. Soil-crop interactions depending on properties of differently-truncated soil profiles caused varying amounts of precipitation and evapotranspiration for the 3-years. Since lysimeter effluent concentrations of DOC (5 ± 0.5 mg L−1) and DIC (62 ± 5 mg L−1) were relatively constant in time, the DOC and DIC leaching was mainly controlled by the water fluxes. Thus, the leaching rates ranged from 0.3 (Luvisol) to 0.5 g m−2 yr−1 (eroded Luvisol) for DOC and 3.3 (Luvisol) to 7.1 g m−2 yr−1 (eroded Luvisol) for DIC. Because of the complex soil crop interactions, a clear relation between erosion-induced soil profile modification and the water balance and DOC and DIC leaching could not be identified. Nevertheless, when transferring lysimeter results to the arable soil landscape the erosion-induced modifications even within the same pedogenetic soil type should be considered.
    Language: English
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
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  • Publication Date: 2016-10-15
    Description: While Ocular Coherence Tomography (OCT) is not a first-line modality to evaluate anterior eye structures terrestrially, it is a resource already available on the International Space Station (ISS) that can be used in medical contingencies that involve the anterior eye. With remote guidance and subject matter expert (SME) support from the ground, a minimally trained crewmember can now use OCT to evaluate anterior eye pathologies on orbit. OCT utilizes low-coherence interferometry to produce detailed cross-sectional and 3D images of the eye in real time. Terrestrially, it has been used to evaluate macular pathologies and glaucoma. Since 2013, OCT has been used onboard the ISS as one part of a suite of hardware to evaluate the Visual Impairment/Intracranial Pressure risk faced by astronauts, specifically assessing changes in the retina and choroid during space flight. The Anterior Segment Module (ASM), an add-on lens, was also flown for research studies, providing an opportunity to evaluate the anterior eye in real time if clinically indicated. Anterior eye pathologies that could be evaluated using OCT were identified. These included corneal abrasions and ulcers, scleritis, and acute angle closure glaucoma. A remote guider script was written to provide ground specialists with step-by-step instructions to guide ISS crewmembers, who do not get trained on the ASM, to evaluate the anterior eye. The instructions were tested on novice subjects and/or operators, whose feedback was incorporated iteratively. The final remote guider script was reviewed by SME optometrists and NASA flight surgeons. The novel application of OCT technology to space flight allows for the acquisition of objective data to diagnose anterior eye pathologies when other modalities are not available. This demonstrates the versatility of OCT and highlights the advantages of using existing hardware and remote guidance skills to expand clinical capabilities in space flight.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37608 , Aerospace Medical Association Scientific Meeting (AsMA); 29 Apr. - 4 May 2017; Denver, CO; United States
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  • Publication Date: 2016-10-15
    Description: Exploration Mission 1 (EM-1) will be the first mission to send an uncrewed Orion vehicle to cislunar space in 2018, targeted to a Distant Retrograde Orbit (DRO). Analysis of EM-1 DRO mission opportunities in 2018 help characterize mission parameters that are of interest to other subsystems (e.g., power, thermal, communications, flight operations, etc). Subsystems request mission design trades which include: landing lighting, addition of an Orion main engine checkout burn, and use of auxiliary thruster only cases. This paper examines the evolving trade studies that incorporate subsystem feedback and demonstrate the feasibility of these constrained mission trajectory designs and contingencies.
    Keywords: Astrodynamics
    Type: JSC-CN-37610 , AAS/AIAA Space Flight Mechanics Meeting; 5-9 Feb. 2017; San Antonio, TX; United States
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  • Publication Date: 2016-10-24
    Description: During a survey of Phytophthora diversity in natural ecosystems in Taiwan six new species were detected. Multigene phylogeny based on the nuclear ITS, ß-tubulin and HSP90 and the mitochondrial cox1 and NADH1 gene sequences demonstrated that they belong to ITS Clade 7a with P. europaea, P. uniformis, P. rubi and P. cambivora being their closest relatives. All six new species differed from each other and from related species by a unique combination of morphological characters, the breeding system, cardinal temperatures and growth rates. Four homothallic species, P. attenuata, P. flexuosa, P. formosa and P. intricata, were isolated from rhizosphere soil of healthy forests of Fagus hayatae, Quercus glandulifera, Q. tarokoensis, Castanopsis carlesii, Chamaecyparis formosensis and Araucaria cunninghamii. Two heterothallic species, P. xheterohybrida and P. xincrassata, were exclusively detected in three forest streams. All P. xincrassata isolates belonged to the A2 mating type while isolates of P. xheterohybrida represented both mating types with oospore abortion rates according to Mendelian ratios (4–33 %). Multiple heterozygous positions in their ITS, ß-tubulin and HSP90 gene sequences indicate that P. xheterohybrida, P. xincrassata and P. cambivora are interspecific hybrids. Consequently, P. cambivora is redescribed as P. xcambivora without nomenclatural act. Pathogenicity trials on seedlings of Castanea sativa, Fagus sylvatica and Q. suber indicate that all six new species might pose a potential threat to European forests.
    Keywords: biosecurity ; breeding systems ; evolution ; flow cytometry ; phylogeny ; Phytophthora cambivora ; radiation
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • Publication Date: 2016-10-25
    Description: To provide multi-centennial, annually-resolved records of climate for arid and semi-arid areas of Australia it is necessary to investigate the potential climate signals in tree species in this large region. Using a stable isotope and x-ray fluorescence approach to dendrochronology in Acacia cambagei, this study demonstrates short (10 years) proxies of temperature and precipitation are possible. Because rings in A. cambagei are difficult to see, precluding traditional dendrochronology, we used elemental abundances of Ca and Sr as an annual chronometer back to 1962. Radiocarbon analysis confirmed that our dating of wood from two trees. We compared δ13C and δ18O from the α-cellulose of the dated wood over the most recent 10 years (n = 10) to local climate records demonstrating significant relationships between δ18O and precipitation (r = −0.85, p < 0.002); mean monthly maximum temperature (r = 0.69, p < 0.03); and drought indexes (CRU scPDSI 0.5°, r = −0.89, p < 0.001) for February and March. Acacia cambagei may be useful in developing regional networks of climate proxies for drought. Using modern trees, in combination with architectural timbers, it may be possible to construct a multi-century, annually-resolved proxy-record of rainfall and temperature for semi-arid north-eastern Australia.
    Type: http://purl.org/escidoc/metadata/ves/publication-types/article
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  • Publication Date: 2016-10-31
    Description: Numerical ice sheet models constrained by theory and refined by comparisons with observational data are a central component of work to address the interactions between the cryosphere and changing climate, at a wide range of scales. Although there continue to be significant advances in modelling, major challenges still exist, in particular in terms of downscaling global climate model output to estimate regional and local climate patterns that are critical controls for the dynamics of glaciers and ice sheets. Ice sheet models are tested and refined by comparing model predictions of past ice geometries with field-based reconstructions from geological, geomorphological, and ice core data. However, on the East Antarctic Ice sheet, there is a critical gap in the empirical data required to reconstruct changes in ice sheet geometry in the Dronning Maud Land (DML) region. In addition, there is poor control on the regional climate history of the ice sheet margin, because ice core locations, where detailed reconstructions of climate history exist, are located on high inland domes. This leaves numerical models of regional glaciation history in this near-coastal area largely unconstrained. MAGIC-DML is an ongoing Swedish-US-Norwegian-German-UK collaboration with a focus on improving ice sheet models by combining advances in modeling with filling critical data gaps that exist in our knowledge of the timing and pattern of ice surface changes on the western Dronning Maud Land margin. A combination of geomorphological mapping using remote sensing data, field investigations, cosmogenic nuclide surface exposure dating, and numerical ice-sheet modelling are being used in an iterative manner to produce a comprehensive reconstruction of the glacial history of western Dronning Maud Land. We present an overview of the project, as well as results of the initial mapping and modelling that has been used to identify high potential sites for field sampling in 2016/17 and 2017/18.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • Publication Date: 2016-11-01
    Description: In the last few years, radio technologies for unmanned aircraft vehicle (UAV) have advanced very rapidly. The increasing need to fly unmanned aircraft systems (UAS) in the national airspace system (NAS) to perform missions of vital importance to national security, defense, and science has pushed ahead the design and implementation of new radio platforms. However, a lot still has to be done to improve those radios in terms of performance and capabilities. In addition, an important aspect to account for is hardware cost and the feasibility to implement these radios using commercial off-the-shelf (COTS) components. UAV radios come with numerous technical challenges and their development involves contributions at different levels of the design. Cognitive algorithms need to be developed in order to perform agile communications using appropriate frequency allocation while maintaining safe and efficient operations in the NAS and, digital reconfigurable architectures have to be designed in order to ensure a prompt response to environmental changes. Command and control (C2) communications have to be preserved during "standard" operations while crew operations have to be minimized. It is clear that UAV radios have to be software-defined systems, where size, weight and power consumption (SWaP) are critical parameters. This paper provides preliminary results of the efforts performed to design a fully digital radio architecture as part of a NASA Phase I STTR. In this paper, we will explain the basic idea and technical principles behind our dynamic/adaptive frequency hopping radio for UAVs. We will present our Simulink model of the dynamic FH radio transmitter design for UAV communications and show simulation results and FPGA system analysis.
    Keywords: Air Transportation and Safety ; Space Sciences (General) ; Communications and Radar
    Type: GRC-E-DAA-TN30791 , Integrated Communication Navigation Systems (ICNS 2016); 19-21 Apr. 2017; Herndon, VA; United States
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  • Publication Date: 2016-11-01
    Description: The surface of Mars once had abundant water flowing on its surface, but now there is a general perception that this surface is completely dry. Several lines of research have shown that there are sources of potentially large quantities of water at many locations on the surface, including regions considered as candidates for future human missions. Traditionally, system designs for these human missions are constrained to tightly recycle water and oxygen, and current resource utilization strategies involve ascent vehicle oxidizer production only. But the assumption of relatively abundant extant water may change this. Several scenarios were constructed to evaluate water requirements for human Mars expeditions to assess the impact to system design if locally produced water is available. Specifically, we have assessed water resources needed for 1) ascent vehicle oxidizer and fuel production, 2) open-loop water and oxygen life support requirements along with more robust usage scenarios, and 3) crew radiation protection augmentation. In this assessment, production techniques and the associated chemistry to transform Martian water and atmosphere into these useful commodities are identified, but production mass and power requirements are left to future analyses. The figure below illustrates the type of water need assessment performed and that will be discussed. There have been several sources of feedstock material discussed in recent literature that could be used to produce these quantities of water. This paper will focus on Mars surface features that resemble glacier-like forms on Earth. Several lines of evidence indicate that some of these features are in fact buried ice, likely remnants from an earlier ice age on Mars. This paper examines techniques and hardware systems used in the polar regions of Earth to access this buried ice and withdraw water from it. These techniques and systems will be described to illustrate options available. A technique known as a Rodriguez Well is assessed as a likely method for extracting water from these bodies of ice. The figure below is a sample of results from this assessment that will be discussed.
    Keywords: Lunar and Planetary Science and Exploration
    Type: JSC-CN-36635-1 , IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-11-03
    Description: NASA, in planning for long-duration missions, has an imperative to provide a food system with the necessary nutrition, acceptability, and safety to ensure sustainment of crew health and performance. The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore the team is challenged to reduce the mass of the food system by 10% while maintaining product safety, nutrition, and acceptability. Commercially available products do not meet the nutritional requirements for a full meal replacement in the spaceflight food system, and it is currently unknown if daily meal replacements will impact crew food intake and psychosocial health over time. The purpose of this study was to develop a variety of nutritionally balanced breakfast replacement bars that meet spaceflight nutritional, microbiological, sensorial, and shelf-life requirements, while enabling a 10% savings in food mass. To date, six nutrient-dense meal replacement bars (approximately 700 calories per bar) have been developed, using traditional methods of compression as well as novel ultrasonic compression technologies developed by Creative Resonance Inc. (Phoenix, AZ). The four highest rated bars were evaluated in the Human Exploration Research Analog (HERA) to assess the frequency with which actual meal replacement options may be implemented. Specifically, overall impact of bars on mood, satiety, digestive discomfort, and satisfaction with food. These factors are currently being analyzed to inform successful implementation strategies where crew maintain adequate food intake. In addition, these bars are currently undergoing shelf-life testing to determine long-term sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. water activity and texture), and microbiological compliance over two years of storage at room temperature and potential temperature abuse conditions to predict long-term acceptability. It is expected that this work will enable a successful meal replacement strategy to be implemented that will maintain crew food consumption and health, while informing exploration missions with appropriate mass savings expectations.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-37796 , 2017 Human Research Program Investigators' Workshop (HRP IWS 2017); 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-02
    Description: Congestion is commonly reported during spaceflight, and most crewmembers have reported using medications for congestion during International Space Station (ISS) missions. Although congestion has been attributed to fluid shifts during spaceflight, fluid status reaches equilibrium during the first week after launch while congestion continues to be reported throughout long duration missions. Congestion complaints have anecdotally been reported in relation to ISS CO2 levels; this evaluation was undertaken to determine whether or not an association exists. METHODS: Reported headaches, congestion symptoms, and CO2 levels were obtained for ISS expeditions 2-31, and time-weighted means and single-point maxima were determined for 24-hour (24hr) and 7-day (7d) periods prior to each weekly private medical conference. Multiple imputation addressed missing data, and logistic regression modeled the relationship between probability of reported event of congestion or headache and CO2 levels, adjusted for possible confounding covariates. The first seven days of spaceflight were not included to control for fluid shifts. Data were evaluated to determine the concentration of CO2 required to maintain the risk of congestion below 1% to allow for direct comparison with a previously published evaluation of CO2 concentrations and headache. RESULTS: This study confirmed a previously identified significant association between CO2 and headache and also found a significant association between CO2 and congestion. For each 1-mm Hg increase in CO2, the odds of a crew member reporting congestion doubled. The average 7-day CO2 would need to be maintained below 1.5 mmHg to keep the risk of congestion below 1%. The predicted probability curves of ISS headache and congestion curves appear parallel when plotted against ppCO2 levels with congestion occurring at approximately 1mmHg lower than a headache would be reported. DISCUSSION: While the cause of congestion is multifactorial, this study showed congestion is associated with CO2 levels on ISS. Data from additional expeditions could be incorporated to further assess this finding. CO2 levels are also associated with reports of headaches on ISS. While it may be expected for astronauts with congestion to also complain of headaches, these two symptoms are commonly mutually exclusive. Furthermore, it is unknown if a temporal CO2 relationship exists between congestion and headache on ISS. CO2 levels were time-weighted for 24hr and 7d, and thus the time course of congestion leading to headache was not assessed; however, congestion could be an early CO2-related symptom when compared to headache. Future studies evaluating the association of CO2-related congestion leading to headache would be difficult due to the relatively stable daily CO2 levels on ISS currently, but a systematic study could be implemented on-orbit if desired.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37736 , Aerospace Medical Association Meeting; 29 Apr. - 4 May 2017; Denver, CO; United States
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  • Publication Date: 2016-11-03
    Description: This panel presents recent updates to and a comprehensive overview of the operational medical support provided to ISS crewmembers in Star City, Russia and Kazakhstan as part of UTMB/KBRwyle's Human Health & Performance contract. With the current Soyuz training flow, physician support is required for nominal training evolutions involving pressure changes or other potential physical risks detailed in this presentation. In addition, full-time physician presence in Star City helps to address the disparity in access to health care in these relatively remote practice areas, while also developing and maintaining relationships with host nation resources. A unique part of standard training in Russia also involves survival training in both winter and water environments; logistic details and medical impacts of each of these training scenarios will be discussed. Following support of a successful training flow, UTMB/KBRwyle's Star City Medical Support Group (SCMSG) is also responsible for configuring medical packs in support of Soyuz launches and landings; we will present the rationale for current pack contents within the context of specific operational needs. With respect to contingency events, the group will describe their preparedness to respond appropriately by activating both local and global resources as necessary, detailing a specialized subset of the group who continually work and update these assets, given changes in international infrastructure and other impacts.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37623 , AsMA Annual Scientific Meeting; 29 Apr. - 4 May 2017 ; Denvor, CO; United States
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  • Publication Date: 2016-11-03
    Description: As spaceflight durations have increased over the last four decades, the effects of microgravity on the human body have become far better understood, as have the exercise countermeasures. Through use of a combination of aerobic and resistive exercise devices, today's astronauts and cosmonauts are able to partially counter the losses in muscle strength, aerobic fitness, and bone strength that otherwise might occur during their missions on the International Space Station (ISS). Since 2000, the ISS has employed a variety of exercise equipment used as countermeasures to these risks. Providing reliable and available exercise systems has presented significant challenges due to the unique environment. In solving these, lessons have been learned that can inform development of future systems.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37633 , JETS-JE11-15-SAIP-DOC-0084 , 2017 IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-11-02
    Description: NASA has established the goal of traveling beyond low-Earth orbit and extending manned exploration to Mars. The length of proposed Mars missions and the lack of resupply missions increases the importance of nutritional content in the food system, which will need a five-year shelf life. The purpose of this research is to assess the stability of vitamin supplementation in traditionally processed spaceflight foods. It is expected that commercially available fortification nutrients will remain stable through a long duration exploration mission at sufficient levels if compatible formulation, processing, and storage temperatures are achieved. Five vitamins (vitamin E, vitamin K, pantothenic acid, folic acid, and thiamin) were blended into a vitamin premix (DSM, Freeport, TX) such that the vitamin concentration per serving equaled 25% of the recommended daily intake after two years of ambient storage. Four freeze-dried foods (Scrambled Eggs, Italian Vegetables, Potatoes Au Gratin, Noodles and Chicken) and four thermo-stabilized foods (Curry Sauce with Vegetables, Chicken Noodle Soup, Grilled Pork Chop, Rice with Butter) were produced, with and without the vitamin premix, to assess the impact of the added fortification on color and taste and to determine the stability of supplemental vitamins in spaceflight foods. The addition of fortification to spaceflight foods did not greatly alter the organoleptic properties of most products. In most cases, overall acceptability scores remained above 6.0 (minimum acceptable score) following six months and one year of low-temperature storage. Likewise, the color of fortified products appears to be preserved over one year of storage. The only exceptions were Grilled pork Chop and Chicken Noodle Soup whose individual components appeareddegrade rapidly over one year of storage. Finally, most vitamins appeared to be stable during long-term storage. The only exception was thiamin, which degraded rapidly during the first year of storage at 35C. It was previously believed that the imprecise method of fortification would prove problematic for nutrient quantification; however, this was only an issue in stored samples of Grilled Pork Chop, Italian Vegetables and Curry Sauce with Vegetables. Year two data may further reveal the extent to which this is a problem, as well as identify overall quality changes over time.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-37794 , NASA HRP Investigators' Workshop; 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-05
    Description: NASA has demonstrated an interest in improving astronaut health and performance through the installment of a new lighting countermeasure on the International Space Station. The Solid State Lighting Assembly (SSLA) system is designed to positively influence astronaut health by providing a daily change to light spectrum to improve circadian entrainment. Unfortunately, existing NASA standards and requirements define ambient light level requirements for crew sleep and other tasks, yet the number of light-emitting diode (LED) indicators and displays within a habitable volume is currently uncontrolled. Because each of these light sources has its own unique spectral properties, the additive lighting environment ends up becoming something different from what was planned or researched. Restricting the use of displays and indicators is not a solution because these systems provide beneficial feedback to the crew. The research team for this grant used computer-based computational modeling and real-world lighting mockups to document the impact that light sources other than the ambient lighting system contribute to the ambient spectral lighting environment. In particular, the team was focused on understanding the impacts of long-term tasks located in front of avionics or computer displays. The team also wanted to understand options for mitigating the changes to the ambient light spectrum in the interest of maintaining the performance of a lighting countermeasure. The project utilized a variety of physical and computer-based simulations to determine direct relationships between system implementation and light spectrum. Using real-world data, computer models were built in the commercially available optics analysis software Zemax Optics Studio(c). The team also built a mockup test facility that had the same volume and configuration as one of the Zemax models. The team collected over 1200 spectral irradiance measurements, each representing a different configuration of the mockup. Analysis of the data showed a measurable impact on ambient light spectrum. This data showed that obvious design techniques exist that can be used to bind the ambient light spectrum closer to the planned spectral operating environment for the observer's eye point. The following observations should be considered when designing an operational environment that is dominated by computer displays. When more light is directed into the field of view of the observer, the greater the impact it will make on various human factors issues that depend on spectral shape and intensity. Because viewing angle has a large part to play in the amount of light flux on the crewmember's retina, beam shape, combined with light source location is an important factor for determining percent probable incident flux on the observer from any combination of light sources. Computer graphics design and display lumen output are major factors influencing the amount of spectrally intense light projected into the environment and in the viewer's direction. Use of adjustable white point display software was useful only if the predominant background color was white and if it matched the ambient light system's color. Display graphics that used a predominantly black background had the least influence on unplanned spectral energy projected into the environment. Percent reflectance makes a difference in total energy reflected back into an environment, and within certain architectural geometries, reflectance can be used to control the amount of a light spectrum that is allowed to perpetuate in the environment. Data showed that room volume and distance from significant light sources influence the total spectrum in a room. Smaller environments had a homogenizing effect on total light spectrum, whereas light from multiple sources in larger environments was less mixed. The findings indicated above should be considered when making recommendations for practice or standards for architectural systems. The ambient lighting system, surface reflectance, and display and indicator implementation all factor into the users' spectral environment. A variety of low-cost solutions exist to mitigate the impact of light from non-architectural lighting systems, and much potential for system automation and integration of display systems with the ambient environment. This team believes that proper planning can be used to avoid integration problems and also believes that human-in-the-loop evaluations, real-world test and measurement, and computer modeling can be used to determine how changes to a process, display graphics, and architecture will help maintain the planned spectral operating lighting environment.
    Keywords: Spacecraft Design, Testing and Performance ; Man/System Technology and Life Support
    Type: JSC-CN-37891 , Human Research Program Investigators' Workshop (HRP IWS 2017); 23-26 Jan. 2017; Glaveston, TX; United States
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  • Publication Date: 2016-11-04
    Description: Enhanced screening for the Visual Impairment/Intracranial Pressure (VIIP) syndrome has been implemented to better characterize the ocular and vision changes observed in some long-duration crewmembers. This includes implementation of in-flight ultrasound in 2010 and optical coherence tomography (OCT) in 2013. Potential risk factors for VIIP include cardiovascular health, diet, anatomical and genetic factors, and environmental conditions. Carbon dioxide (CO2), a potent vasodilator, is chronically elevated on the International Space Station (ISS) relative to ambient levels on Earth, and is a plausible risk factor for VIIP. In an effort to understand the possible associations between CO2 and VIIP, this study explores the relationship of ambient CO2 levels on ISS compared to inflight ultrasound and OCT measures of the eye obtained from ISS crewmembers. CO2 measurements were aggregated from Operational Data Reduction Complex and Node 3 major constituent analyzers (MCAs) on ISS or from sensors located in the European Columbus module, as available. CO2 levels in the periods between each ultrasound and OCT session are summarized using timeseries metrics, including time-weighted means and variances. Partial least squares regression analyses are used to quantify the complex relationship between specific ultrasound and OCT measures and the CO2 metrics simulataneously. These analyses will enhance our understanding of the possible associations between CO2 levels and structural changes to the eye which will in turn inform future analysis of inflight VIIP data.
    Keywords: Life Sciences (General) ; Aerospace Medicine
    Type: JSC-CN-37739 , Human Research Program Investigators' Workshop (2017 HRP IWS); 23-27 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-05
    Description: For the past four years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Most importantly, the AQM operates at atmospheric pressure and uses air as the GC carrier gas, which translates into a small reliable instrument. Onboard ISS there are two AQMs, with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard ISS for each crew increment. The U.S. Navy is looking to update its submarine air monitoring suite of instruments, and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which was successfully flown on ISS as a technology demonstration to measure major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial results. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only one AQM will be deployed during the sea trial, but it is sufficient to detect the compounds of interest to the Navy for the purposes of this trial. A significant benefit of the AQM is that runs can be scripted for pre-determined intervals and no crew intervention is required. The data from the sea trial will be compared to archival samples collected prior to and during the trial period. This paper will give a brief overview of the AQM technology and protocols for the submarine trial. After a quick review of the AQM preparation, the main focus of the paper will be on the results of the submarine trial. Of particular interest will be the comparison of the contaminants found in the ISS and submarine atmospheres, as both represent closed environments. In U.K. submarine trials in the early 2000s, the submarine and ISS atmospheres were found to be remarkably similar.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-37932 , International Conference on Environmental Systems (ICES); 16-20 Jul. 2017; Charleston, SC; United States
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  • Publication Date: 2016-11-05
    Description: Future exploration missions will be the first time humanity travels beyond Low Earth Orbit (LEO) since the Apollo program, taking us to cis-lunar space, interplanetary space, and Mars. These long-duration missions will cover vast distances, severely constraining opportunities for emergency evacuation to Earth and cargo resupply opportunities. Communication delays and blackouts between the crew and Mission Control will eliminate reliable, real-time telemedicine consultations. As a result, compared to current LEO operations onboard the International Space Station, exploration mission medical care requires an integrated medical system that provides additional in-situ capabilities and a significant increase in crew autonomy. The Medical System Concept of Operations for Mars Exploration Missions illustrates how a future NASA Mars program could ensure appropriate medical care for the crew of this highly autonomous mission. This Concept of Operations document, when complete, will document all mission phases through a series of mission use case scenarios that illustrate required medical capabilities, enabling the NASA Human Research Program (HRP) Exploration Medical Capability (ExMC) Element to plan, design, and prototype an integrated medical system to support human exploration to Mars.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37894 , Human Research Program Investigators' Workshop (HRP IWS 2017 ); 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-05
    Description: Back by popular demand, the JSC Biostatistics Laboratory and LSAH statisticians are offering an opportunity to discuss your statistical challenges and needs. Take the opportunity to meet the individuals offering expert statistical support to the JSC community. Join us for an informal conversation about any questions you may have encountered with issues of experimental design, analysis, or data visualization. Get answers to common questions about sample size, repeated measures, statistical assumptions, missing data, multiple testing, time-to-event data, and when to trust the results of your analyses.
    Keywords: Statistics and Probability
    Type: JSC-CN-37884 , 2017 Human Research Program Investigators' Workshop (HRP IWS) ; 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-05
    Description: INTRODUCTION: Long-duration missions beyond low Earth orbit introduce new constraints to the space medical system. Beyond the traditional limitations in mass, power, and volume, consideration must be given to other factors such as the inability to evacuate to Earth, communication delays, and limitations in clinical skillsets. As NASA develops the medical system for an exploration mission, it must have an ability to evaluate the trade space of what resources will be most important. The Medical Optimization Network for Space Telemedicine Resources (MONSTR) was developed over the past year for this reason, and is now a system for managing data pertaining to medical resources and their relative importance when addressing medical conditions. METHODS: The MONSTR web application with a Microsoft SQL database backend was developed and made accessible to Tableau v9.3 for analysis and visualization. The database was initially populated with a list of medical conditions of concern for an exploration mission taken from the Integrated Medical Model (IMM), a probabilistic model designed to quantify in-flight medical risk. A team of physicians working within the Exploration Medical Capability Element of NASA's Human Research Program compiled a list diagnostic and treatment medical resources required to address best- and worst-case scenarios of each medical condition using a terrestrial standard of care and entered this data into the system. This list included both tangible resources (e.g. medical equipment, medications) and intangible resources (e.g. clinical skills required to perform a procedure). The physician team then assigned criticality values to each instance of a resource, representing the importance of that resource to diagnosing or treating its associated condition(s). Medical condition probabilities of occurrence during a Mars mission were pulled from the IMM and imported into the MONSTR database for use within a resource criticality-weighting algorithm. DISCUSSION: The MONSTR tool is a novel approach to assess the relative value of individual resources needed for the diagnosis and treatment of medical conditions. Future work will add resources for prevention and long term care of these conditions. Once data collection is complete, MONSTR will provide the operational and research communities at NASA with information to support informed decisions regarding areas of research investment, future crew training, and medical supplies manifested as part of any exploration medical system.
    Keywords: Aerospace Medicine ; Computer Programming and Software
    Type: JSC-CN-37819 , NASA Human Research Program Investigators' Workshop (HRP IWS 2017); 23-26 Jan. 2016; Galveston, TX; United States
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  • Publication Date: 2016-11-05
    Description: Cross-system studies on the response of different ecosystems to global change will support our understanding of ecological changes. Synoptic views on the planet's two main realms, the marine and terrestrial, however, are rare, owing to the development of rather disparate research communities.We combined questionnaires and a literature review to investigate howthe importance of anthropogenic drivers of biodiversity change differs amongmarine and terrestrial systems and whether differences perceived by marine vs. terrestrial researchers are reflected by the scientific literature. This included asking marine and terrestrial researchers to rate the relevance of different drivers of global change for either marine or terrestrial biodiversity. Land use and the associated loss of natural habitatswere rated as most important in the terrestrial realm,while the exploitation of the sea by fishing was rated as most important in the marine realm. The relevance of chemicals, climate change and the increasing atmospheric concentration of CO2 were rated differently for marine and terrestrial biodiversity respectively. Yet, our literature review provided less evidence for such differences leading to the conclusion that while the history of the use of land and sea differs, impacts of global change are likely to become increasingly similar.
    Repository Name: EPIC Alfred Wegener Institut
    Language: en
    Type: Article , NonPeerReviewed
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  • Publication Date: 2016-11-08
    Description: Human missions to Mars may require radical changes in the approach to extra-vehicular (EVA) suit design. A major challenge is the balance of building a suit robust enough to complete multiple EVAs under intense ultraviolet (UV) light exposure without losing mechanical strength or compromising the suit's mobility. To study how the materials degrade on Mars in-situ, the Jet Propulsion Laboratory (JPL) invited the Advanced Space Suit team at NASA's Johnson Space Center (JSC) to place space suit materials on the Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals (SHERLOC) instrument's calibration target of the Mars 2020 rover. In order to select materials for the rover and understand the effects from Mars equivalent UV exposure, JSC conducted ground testing on both current and new space suit materials when exposed to 2500 hours of Mars mission equivalent UV. To complete this testing, JSC partnered with NASA's Marshall Space Flight Center to utilize their UV vacuum chambers. Materials tested were Orthofabric, polycarbonate, Teflon, Dacron, Vectran, spectra, bladder, nGimat coated Teflon, and nGimat coated Orthofabric. All samples were measured for mass, tensile strength, and chemical composition before and after radiation. Mass loss was insignificant (less than 0.5%) among the materials. Most materials loss tensile strength after radiation and became more brittle with a loss of elongation. Changes in chemical composition were seen in all radiated materials through Spectral Analysis. Results from this testing helped select the materials that will fly on the Mars 2020 rover. In addition, JSC can use this data to create a correlation to the chemical changes after radiation-which is what the rover will send back while on Mars-to the mechanical changes, such as tensile strength.
    Keywords: Man/System Technology and Life Support
    Type: JSC-CN-37805 , International Conference on Environmental Systems (ICES 2017); 16-20 Jul. 2017; Charleston, SC; United States
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  • facet.materialart.
    Springer
    , ed. by Brasseur, G. P., Jacob, D. and Schuck-Zöller, S. Springer, Berlin, Germany, 348 pp. ISBN 978-3-662-50397-3
    Publication Date: 2016-11-11
    Description: Erstmals trägt dieses nationale Assessment den Forschungsstand zum Klimawandel umfassend für alle Themenbereiche und gesellschaftlichen Sektoren zusammen. Womit müssen wir in Deutschland rechnen, welche Auswirkungen werden die Klimaveränderungen auf Wirtschaft und Gesellschaft haben, und wie können wir uns wappnen? 126 Autoren aus ganz Deutschland äußern sich zu Themen wie bereits beobachtete und zukünftige Veränderungen, Wetterkatastrophen und deren Folgen, den Projektionen für die Zukunft, den Risiken sowie möglichen Anpassungsstrategien. Die Autoren stellen in verständlicher Sprache den aktuellen Forschungsstand dar und veranschaulichen die wichtigsten Gedanken in Grafiken und Tabellen. Alle Texte wurden mehrfach wissenschaftlich begutachtet. Klimawandel in Deutschland ist die erste Gesamtschau zu dem Themenkomplex, benennt offene Fragestellungen und liefert eine Grundlage für Entscheidungen im Zusammenhang mit dem Klimawandel. Deutschland reiht sich damit ein in die Liste von Ländern wie die Vereinigten Staaten, Österreich und Großbritannien, in denen derartige Berichte bereits vorliegen. Die Herausgeber: Prof. Dr. Guy Brasseur und Prof. Dr. Daniela Jacob, ehemaliger Direktor und gegenwärtige Direktorin des Climate Center Germany/Helmholtz-Zentrum Geesthacht, und Susanne Schuck-Zöller, die auch die Projektleitung übernommen hat, werden bei diesem Buch unterstützt von einem Editorial Board, dem elf herausragende Wissenschaftler aus den wichtigsten Klimaforschungseinrichtungen in Deutschland angehören
    Repository Name: Oceanrep Geomar
    Type: Book , NonPeerReviewed
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  • Publication Date: 2016-11-11
    Description: This study was the first in a series of planned tests to use physics-based subsystem simulations to investigate the interactions between a spacecraft's crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation models the life support system of a deep space habitat. It contains models of an environmental control and life support system, an electrical power system, an active thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the subsystems; 2) a mission control center interface with data transport delays up to 15 minute each way; and 3) a real-time simulation test conductor interface used to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission. The NEEMO crew and ground support team performed a number of relevant deep space mission scenarios that included both nominal activities and activities with system malfunctions. While this initial test sequence was focused on test infrastructure and procedures development, the data collected in the study already indicate that long communication delays have notable impacts on the operation of deep space systems. For future human missions beyond cis-lunar, NASA will need to design systems and support tools to meet these challenges. These will be used to train the crew to handle critical malfunctions on their own, to predict malfunctions and assist with vehicle operations. Subsequent more detailed and involved studies will be conducted to continue advancing NASA's understanding of space systems operations across long communications delays.
    Keywords: Ground Support Systems and Facilities (Space) ; Space Communications, Spacecraft Communications, Command and Tracking
    Type: JSC-CN-37700 , 2017 IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-11-15
    Description: In this study, we report an extensive paleomagnetic study (76 sites) carried out in the Alborz Mts. (northern Iran), with the aim of reconstructing the rotation history and the origin of curvature of this orogenic chain. The analyzed deposits are the sedimentary successions of the Upper Red Formation (Miocene), Lower Red Formation (Oligocene) and Eocene clastic units. Paleomagnetic results indicate that the Alborz Mts. can be considered a secondary arc that originated as a linearmountain belt that progressively acquired its present day curvature through opposite vertical axis rotations along its strike. The curvature of the arc was entirely acquired after the middlelate Miocene,which is the age of the youngest investigated sediments (Upper Red Formation). Overall, our paleomagnetic data indicate that the Alborz Mts. can be considered an orocline. Our results define, for the first time, the rotational history of the entire Alborz curved mountain belt, and enable us to reconstruct the paleogeographic and tectonic evolution of northern Iran in the framework of Arabia-Eurasia continental deformation. The kinematics inferred by the pattern of paleomagnetic rotations is at odds with the present day kinematics of northern Iran, characterized by the westward extrusion of the South Caspian block, and by a left lateral shear between Central Iran and the central and western sectors of the Alborz Mts. By integrating paleomagnetic datawith stratigraphic, thermochronological, structural and GPS information,we propose that the initiation of South Caspian subduction and the activation of westward extrusion of South Caspian block occurred diachronously and that the initiation of the present-day kinematics of northern Iran was quite recent (Lower Pleistocene, b2 Ma).
    Keywords: Paleomagnetism Alborz Iran orocline ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Language: English
    Type: article
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  • Publication Date: 2016-11-18
    Description: This paper presents the results of a NASA initiated Agency-wide assessment to better characterize the risks and potential mitigation approaches associated with landing human class Entry, Descent, and Landing (EDL) systems on Mars. Due to the criticality and long-lead nature of advancing EDL techniques, it is necessary to determine an appropriate strategy to improve the capability to land large payloads. A key focus of this study was to understand the key EDL risks and with a focus on determining what "must" be tested at Mars. This process identified the various risks and potential risk mitigation strategies along with the key near term technology development efforts required and in what environment those technology demonstrations were best suited. The study identified key risks along with advantages to each entry technology. In addition, it was identified that provided the EDL concept of operations (con ops) minimized large scale transition events, there was no technology requirement for a Mars pre-cursor demonstration. Instead, NASA should take a direct path to a human-scale lander.
    Keywords: Spacecraft Design, Testing and Performance
    Type: JSC-CN-37782 , IEEE Aerospace Conference; 4-11 Mar. 2017; Big Sky, MT; United States
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  • Publication Date: 2016-11-23
    Type: inbook
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  • Publication Date: 2016-11-23
    Type: inbook
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  • facet.materialart.
    Springer Spektrum
    Klimawandel in Deutschland
    Publication Date: 2016-11-23
    Type: inbook
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  • facet.materialart.
    Springer Spektrum
    Klimawandel in Deutschland
    Publication Date: 2016-11-23
    Type: inbook
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  • facet.materialart.
    Springer Spektrum
    Klimawandel in Deutschland
    Publication Date: 2016-11-23
    Type: inbook
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  • Publication Date: 2016-11-23
    Type: inbook
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  • Publication Date: 2016-11-23
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  • Publication Date: 2016-11-23
    Description: Astronauts experience sensorimotor disturbances during their initial exposure to microgravity and during the re-adaptation phase following a return to an Earth-gravitational environment. These alterations may disrupt crewmembers' ability to perform mission critical functional tasks requiring ambulation, manual control and gaze stability. Interestingly, astronauts who return from spaceflight show substantial differences in their abilities to readapt to a gravitational environment. The ability to predict the manner and degree to which individual astronauts are affected will improve the effectiveness of countermeasure training programs designed to enhance sensorimotor adaptability. For such an approach to succeed, we must develop predictive measures of sensorimotor adaptability that will allow us to foresee, before actual spaceflight, which crewmembers are likely to experience greater challenges to their adaptive capacities. The goals of this project are to identify and characterize this set of predictive measures. Our approach includes: 1) behavioral tests to assess sensory bias and adaptability quantified using both strategic and plastic-adaptive responses; 2) imaging to determine individual brain morphological and functional features, using structural magnetic resonance imaging (MRI), diffusion tensor imaging, resting state functional connectivity MRI, and sensorimotor adaptation task-related functional brain activation; and 3) assessment of genetic polymorphisms in the catechol-O-methyl transferase, dopamine receptor D2, and brain-derived neurotrophic factor genes and genetic polymorphisms of alpha2-adrenergic receptors that play a role in the neural pathways underlying sensorimotor adaptation. We anticipate that these predictive measures will be significantly correlated with individual differences in sensorimotor adaptability after long-duration spaceflight and exposure to an analog bed rest environment. We will be conducting a retrospective study, leveraging data already collected from relevant ongoing or completed bed rest and spaceflight studies. This data will be combined with predictor metrics that will be collected prospectively (as described for behavioral, brain imaging and genomic measures) from these returning subjects to build models for predicting post spaceflight and bed rest adaptive capability. In this presentation we will discuss the optimized set of tests for predictive metrics to be used for evaluating post mission adaptive capability as manifested in their outcome measures. Comparisons of model performance will allow us to better design and implement sensorimotor adaptability training countermeasures against decrements in post-mission adaptive capability that are customized for each crewmember's sensory biases, adaptive ability, brain structure, brain function, and genetic predispositions. The ability to customize adaptability training will allow more efficient use of crew time during training and will optimize training prescriptions for astronauts to mitigate the deleterious effects of spaceflight.
    Keywords: Behavioral Sciences ; Aerospace Medicine
    Type: JSC-CN-38005 , Human Research Program Investigators' Workshop ; 23-27 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-23
    Description: Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid pulsatility); (5) ocular measures (optical coherence tomography; intraocular pressure; 2-dimensional ultrasound including optic nerve sheath diameter, globe flattening, and retina-choroid thickness; Doppler ultrasound of ophthalmic and retinal arteries and veins); (6) cardiac variables by ultrasound (inferior vena cava, tricuspid flow and tissue Doppler, pulmonic valve, stroke volume, right heart dimensions and function, four-chamber views); and (7) ICP measures (tympanic membrane displacement, otoacoustic emissions). Pre- and post-flight, acute head-down tilt will induce cephalad fluid shifts, whereas lower body negative pressure will oppose these shifts. Controlled Mueller maneuvers will manipulate cardiovascular variables. Through interventions applied before, during, and after flight, we intend to fully evaluate the relationship between fluid shifts and the VIIP syndrome. Discussion. Ten subjects have consented to participate in this experiment, including the recent One-Year Mission crewmembers, who have recently completed R plus180 testing; all other subjects have completed pre-flight testing. Preliminary results from the One-Year Mission crewmembers will be presented, including measures of ocular structure and function, vascular dimensions, fluid distribution, and non-invasive estimates of intracranial pressure.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37997 , 2017 NASA Human Research Program Investigators' Workshop (HRP IWS 2017); 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-23
    Description: Long-term exposure to microgravity causes sensorimotor adaptations that result in functional deficits upon returning to a gravitational environment. At landing, the vestibular system and the central nervous system, responsible for coordinating head and eye movements via the vestibulo-occular reflex (VOR), are adapted to microgravity and must re-adapt to the Earth's gravitational environment. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with astronauts reporting oscillopsia and blurred vision. These effects are caused by retinal slip, or the inability to keep an image focused on their retina, which is thought to drive motion sickness symptoms experienced upon landing. Retinal slip can be estimated by dynamic visual acuity (DVA); visual acuity while in motion. Peters et al. (2011) find that DVA is worsened in astronauts by an average of 0.75 eye-chart lines one day after landing. Previously, the use of stroboscopic goggles has shown to be effective in minimizing motion sickness symptoms due to retinal slip (Reschke et al. 2007). In this study, we simulated the decrement in DVA caused by sensorimotor re-adaptation by using minifying lenses and then testing the efficacy of stroboscopic goggles in preventing retinal slip and improving DVA. Dynamic visual acuity is assessed using an oscillating chair developed in the Neuroscience Laboratory at JSC. This chair is motor-driven and oscillates vertically at 2 Hz with a vertical displacement of +/- 2 cm to simulate the vertical translations that occur while walking. As the subject is being oscillated, they are asked to discern the direction of Landolt-C optotypes of varying sizes and record their direction using a gamepad. The visual acuity thresholds are determined using an algorithm that alters the size of the optotype based on the previous responses of the subject using a forced-choice best parameter estimation that is able to rapidly converge on the threshold value. Visual acuity thresholds were determined both for static (seated) and dynamic (oscillating) conditions. Dynamic visual acuity is defined as the difference between the dynamic and static conditions. We found that healthy subjects (n=20) have a significantly impaired DVA while wearing the minifying lenses, demonstrating that the VOR is in an adaptive state and retinal slip is occurring. When subjects' acuity was tested wearing the stroboscopic goggles with the minifying lenses, there was no significant difference in their DVA compared to their baseline DVA. This suggests that stroboscopic goggles are preventing retinal slip and would function as an efficient countermeasure for VOR adaptations and thus help mitigate landing sickness symptoms experienced by long-duration crewmembers. These goggles might also be used to counter blurred vision (caused by retinal slip) experienced by crewmembers during launch where the vehicle vibrations are greatest. The stroboscopic effect could be built into a section of their head mounted displays on the visor of their helmets to be used in these high vibration situation if a mission critical task is necessary.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37995 , Human Research Program Investigators' Workshop; 23-26 Jan. 2017; Galveston, TX; United States
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  • Publication Date: 2016-11-23
    Description: Background: Carotid Intima Media Thickness (CIMT) has been demonstrated to be predictive of future cardiovascular events. Within various populations, radiation exposure, stress, and physical confinement have all been linked to an increased CIMT. Recent research discovered CIMT was significantly increased in ten long duration astronauts from pre-flight to four days post flight. The relationship between spaceflight and CIMT is not understood and trends in CIMT within the larger astronaut population are unknown. Methods: In 2010, CIMT was offered as part of the astronaut annual exam at the JSC Flight Medicine Clinic using a standardized CIMT screening protocol and professional sonographers. Between 2010 and 2016, CIMT measurements were collected on 213 NASA astronauts and payload specialists. The values used in this retrospective chart review are the mean of the CIMT from the right and left. Spaceflight exposure was categorized based on the total number of days spent in space at the time of the ground-based ultrasound (0, 1-29, 30-100, 101-200, 200). Linear regression with generalized estimating equations were used to estimate the association between spaceflight exposures and CIMT. Results: 530 studies were completed among 213 astronauts with a mean of 2.5 studies (range 1-6) per astronaut over the six year period. As in other populations, CIMT was significantly associated with age; however, gender was not. While there was no significant direct correlation between total spaceflight exposure and CIMT found, astronauts with 30-100 spaceflight days and astronauts with greater than 100 spaceflight days had significantly increased CIMT over astronauts who had never flown (p=0.002 and p=<0.0001 respectively) after adjustment for age. Conclusion: Further work is needed to fully understand CIMT and its association to spaceflight. Current occupational surveillance activities are under way to study CIMT values in conjunction with other cardiovascular risk factors among astronauts as compared to the general population.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37929 , Annual Scientific Meeting of the Aerospace Medical Association; 29 Apr. - 4 May 2017; Denver, CO; United States
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  • Publication Date: 2016-11-23
    Description: Introduction. This joint European Space Agency/NASA pre- and post-flight study investigates the influence of exposure to microgravity on the subjective straight ahead (SSA) in crewmembers returning from long-duration expeditions to the International Space Station (ISS). The SSA is a measure of the internal representation of body orientation and to be influenced by stimulation of sensory systems involved in postural control. The use of a vibrotactile sensory aid to correct the representation of body tilted relative to gravity is also tested as a countermeasure. This study addresses the sensorimotor research gap to "determine the changes in sensorimotor function over the course of a mission and during recovery after landing." Research Plans. The ISS study will involve eight crewmembers who will participate in three pre-flight sessions (between 120 and 60 days before launch) and then three post-flight sessions on R plus 0/1 day, R plus 4 days, and R plus 8 days. Sixteen control subjects were also tested during three sessions to evaluate the effects of repeated testing and to establish normative values. The experimental protocol includes measurements of gaze and arm movements during the following tasks: (1) Near & Far Fixation: The subject is asked to look at actual targets in the true straight-ahead direction or to imagine these targets in the dark. Targets are located at near distance (arm's length) and far distance (beyond 2 meters). This task is successively performed with the subject's body aligned with the gravitational vertical, and with the subject's body tilted in pitch relative to the gravitational vertical using a tilt chair. Measures are then compared with and without a vibrotactile sensory aid that indicates how far one has tilted relative to the vertical; (2) Eye and Arm Movements: The subject is asked to look and point in the SSA direction in darkness and then make horizontal and vertical eye or arm movements, relative to Earth coordinates (allocentric) and to the subject's head/body reference (egocentric). This task is successively performed with the subject's body aligned with the gravitational vertical, and with subject's body tilted in roll using a tilt chair; (3) Linear Vestibulo-Ocular Reflex: The subject is asked to fixate actual visual targets at near and far distances in the true straight-ahead direction, and to evaluate the distance of these targets. The subject is asked to continue fixating the same imagined targets in darkness while he/she is passively accelerated up and down on a spring-loaded vertical linear accelerator. Results. In the control subject population, the perceived tilt angles, translations, and distances were remarkably close to the actual values. The pointing tasks indicated that the orientation of arm saccades was influenced by both the gravitational vertical and the body idiotropic vector. Repeating the testing did not reveal any significant changes. Preliminary results obtained in three crewmembers before and after flight will also be presented. Applications. A change in an individual's egocentric reference might have negative consequences on evaluating the direction of an approaching object or on the accuracy of reaching movements or locomotion. Consequently, investigating how microgravity affects the target location will have theoretical, operational, and even clinical implications for future space exploration missions. The use of vibrotactile feedback as a sensorimotor countermeasure is applicable to balance therapy applications for patients with vestibular loss and the elderly to mitigate risks due to loss of spatial orientation.
    Keywords: Aerospace Medicine
    Type: JSC-CN-37991 , 2017 NASA Human Research Program Investigators' Workshop (HRP IWS 2017); 23-26 Jan. 2017; Galveston, TX; United States
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