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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Loss of 'complexity' and aging. Potential applications of fractals and chaos theory to senescence

The concept of "complexity," derived from the field of nonlinear dynamics, can be adapted to measure the output of physiologic processes that generate highly variable fluctuations resembling "chaos." We review data suggesting that physiologic aging is associated with a generalized loss of such complexity in the dynamics of healthy organ system function and hypothesize that such loss of complexity leads to an impaired ability to adapt to physiologic stress. This hypothesis is supported by observations showing an age-related loss of complex variability in multiple physiologic processes including cardiovascular control, pulsatile hormone release, and electroencephalographic potentials. If further research supports this hypothesis, measures of complexity based on chaos theory and the related geometric concept of fractals may provide new ways to monitor senescence and test the efficacy of specific interventions to modify the age-related decline in adaptive capacity.

Non-NASA Center↗
NASA NTRS2006

Optical Coatings and Surfaces in Space: MISSE

The space environment presents some unique problems for optics. Components must be designed to survive variations in temperature, exposure to ultraviolet, particle radiation, atomic oxygen and contamination from the immediate environment. To determine the importance of these phenomena, a series of passive exposure experiments have been conducted which included, among others, the Long Duration Exposure Facility (LDEF, 1985- 1990), the Passive Optical Sample Assembly (POSA, 1996- 1997) and most recently, the Materials on the International Space Station Experiment (MISSE, 2001 - 2005). The MISSE program benefited greatly from past experience so that at the conclusion of this 4 year mission, samples which remained intact were in remarkable condition. This study will review data from different aspects of this experiment with emphasis on optical properties and performance.

Stewart, Alan F.↗
NASA NTRS2012

Astronaut Biography Project for Countermeasures of Human Behavior and Performance Risks in Long Duration Space Flights

This final report will summarize research that relates to human behavioral health and performance of astronauts and flight controllers. Literature reviews, data archival analyses, and ground-based analog studies that center around the risk of human space flight are being used to help mitigate human behavior and performance risks from long duration space flights. A qualitative analysis of an astronaut autobiography was completed. An analysis was also conducted on exercise countermeasure publications to show the positive affects of exercise on the risks targeted in this study. The three main risks targeted in this study are risks of behavioral and psychiatric disorders, risks of performance errors due to poor team performance, cohesion, and composition, and risks of performance errors due to sleep deprivation, circadian rhythm. These three risks focus on psychological and physiological aspects of astronauts who venture out into space on long duration space missions. The purpose of this research is to target these risks in order to help quantify, identify, and mature countermeasures and technologies required in preventing or mitigating adverse outcomes from exposure to the spaceflight environment

Banks, Akeem↗
NASA NTRS2012

Automation and Process Improvement Enables a Small Team to Operate a Low Thrust Mission in Orbit Around the Asteroid Vesta

NASA's Dawn mission to the asteroid Vesta and dwarf planet Ceres launched September 27, 2007 and arrived at Vesta in July of 2011. This mission uses ion propulsion to achieve the necessary delta-V to reach and maneuver at Vesta and Ceres. This paper will show how the evolution of ground system automation and process improvement allowed a relatively small engineering team to transition from cruise operations to asteroid operations while maintaining robust processes. The cruise to Vesta phase lasted almost 4 years and consisted of activities that were built with software tools, but each tool was open loop and required engineers to review the output to ensure consistency. Additionally, this same time period was characterized by the evolution from manually retrieved and reviewed data products to automatically generated data products and data value checking. Furthermore, the team originally took about three to four weeks to design and build about four weeks of spacecraft activities, with spacecraft contacts only once a week. Operations around the asteroid Vesta increased the tempo dramatically by transitioning from one contact a week to three or four contacts a week, to fourteen contacts a week (every 12 hours). This was accompanied by a similar increase in activity complexity as well as very fast turn around activity design and build cycles. The design process became more automated and the tools became closed loop, allowing the team to build more activities without sacrificing rigor. Additionally, these activities were dependent on the results of flight system performance, so more automation was added to analyze the flight data and provide results in a timely fashion to feed the design cycle. All of this automation and process improvement enabled up the engineers to focus on other aspects of spacecraft operations, including spacecraft health monitoring and anomaly resolution.

ground system automation↗
NASA NTRS2012

Characterization of Tantalum Polymer Capacitors

Overview Reviewed data Caution must be taken when accelerating test conditions Data not useful to establish an acceleration model Introduction of new failure mechanism skewing results Evidence of Anti-Wear-Out De-doping of polymer Decreased capacitance Increased ESR Not dielectric breakdown Needs further investigation Further investigation into tantalum polymer capacitor technology Promising acceleration model for Manufacturer A Possibility for use in high-reliability space applications with suitable voltage derating.

Voltage Acceleration↗
NASA NTRS2012

NASA Electronic Parts and Packaging (NEPP) Program

Recent Findings from Audits, New Technology Data Reviews a) Disabled Chip Burn-ins A recent audit for a QML device discovered that the chip was disabled during the static burn-in, thus it was not drawing any current. Recommendation: For new SMDs add a statement within the burn-in paragraphs stating that the parts shall be kept in their enabled state during the burn-in. b) Class Q 160-hr/125oC Burn-in This is being interpreted as a static burn-in (even for CMOS technology). Recommendation: Provide clarification in MIL-STD-883, Test Method 5004. c) At Frequency (Dynamic) Burn-ins Test equipment limitation is being cited for not doing burn-ins at the application frequency. Recommendation: The burn-in task group to discuss and provide guidance. When the SMD says that the part can be used at 200 MHz, then doing burn-in at 6 MHz (cited as burn-in equipment limitation frequency) is not going to be meaningful! d) Two Static Burn-ins Some manufacturers are doing electrical testing between the two static burn-ins, whereas others do electricals after completing both static burn-ins. Recommendation: Provide clarification in MIL-STD-883, Test Method 5004. e) Thermal Imaging For a device with hot spots, the thermal resistance, junction-to-case, would be much higher than the guidelines given in MIL-STD-1835. One of the suppliers used thermal imaging to find hot spots on the die. Recommendation: Assign a task group to evaluate the effectiveness of thermal imaging at the product development stage.

Class Y↗
NASA NTRS2013

Carbon Dioxide: Surprising Effects on Decision Making and Neurocognitive Performance

The occupants of modern submarines and the International Space Station (ISS) have much in common as far as their air quality is concerned. Air is polluted by materials offgassing, use of utility compounds, leaks of systems chemicals, and anthropogenic sources. The primary anthropogenic compound of concern to submariners and astronauts has been carbon dioxide (CO2). NASA and the US Navy rely on the National Research Council Committee on Toxicology (NRC-COT) to help formulate exposure levels to CO2 that are thought to be safe for exposures of 3-6 months. NASA calls its limits Spacecraft Maximum Allowable Concentrations (SMACs). Years of experience aboard the ISS and a recent publication on deficits in decision making in ground-based subjects exposed briefly to 0.25% CO2 suggest that exposure levels that have been presumed acceptable to preserve health and performance need to be reevaluated. The current CO2 exposure limits for 3-6 months set by NASA and the UK Navy are 0.7%, and the limit for US submariners is 0.5%, although the NRC-COT recommended a 90-day level of 0.8% as safe a few years ago. NASA has set a 1000-day SMAC at 0.5% for exploration-class missions. Anecdotal experience with ISS operations approaching the current 180-day SMAC of 0.7% suggest that this limit is too high. Temporarily, NASA has limited exposures to 0.5% until further peer-reviewed data become available. In the meantime, a study published last year in the journal Environmental Health Perspectives (Satish U, et al. 2012) demonstrated that complexdecision- making performance is somewhat affected at 0.1% CO2 and becomes "dysfunctional" for at least half of the 9 indices of performance at concentrations approaching 0.25% CO2. The investigators used the Strategic Management Simulation (SMS) method of testing for decisionmaking ability, and the results were so surprising to the investigators that they declared that their findings need to be independently confirmed. NASA has responded to the findings on decision making by developing a study to either confirm or refute the published results. In addition, other neurocognitive tests that have been and will be used aboard the ISS will be part of the ground-based study. Further evaluations during the exposures will include ocular and cardiovascular effects of CO2 exposure. In addition, the 1- carbon genetics of the test subjects will be evaluated to determine if any individual subjects are unusually susceptible to CO2 exposure because of genetic factors. Our plan is to extend the published study from Satish by employing a wider series of CO2 exposures to include concentrations of 0.06, 0.12, 0.25, and 0.50%. We believe that our findings will be of keen interest to submariners and to those designing "tight" buildings.

James, John T.↗
NASA NTRS2014

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs)

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This report contains the outcome of the assessment and the findings, observations, and NESC recommendations to the Agency and individual NASA Centers.

Prosser, William H.↗
NASA NTRS2014

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs) : Appendices - Volume 2

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This document contains the appendices to the main report.

Prosser, William H.↗
NASA NTRS2014

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs)

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This report contains the outcome of the assessment and the findings, observations, and NESC recommendations to the Agency and individual NASA Centers.

Prosser, William H.↗
NASA NTRS2018

Investigation of Silver Biocide as a Disinfection Technology for Spacecraft-An Early Literature Review

An ideal spacecraft water disinfection system should prevent or control microbial growth, inhibit or prevent biofilm formation, and prevent microbial-induced corrosion. In addition, the selected biocide system should be chemically compatible with materials used in the water storage and distribution system, have minimal maintenance requirements, especially for long-duration missions, and should be safe for crew consumption at levels appropriate for biocidal control. Silver ion is a proven broad spectrum biocide. There has been an increased interest in the biocidal function of silver, both due to its potential to control biocide resistant species and due to advances in silver and nanosilver biocide technologies. NASA is considering silver as the future biocide for exploration over the iodine biocide system. In order to select and design a successful silver biocide delivery system to meet NASA's requirements, it is essential to understand the advantages and disadvantages of moving to a silver disinfection system. To enhance the knowledge base for the application of silver biocides in spacecraft water systems, this paper provides a first compilation of review data related to: (1) Silver as a biocide technology, (2) Options and concepts for silver biocide delivery, and (3) Silver biocide compatibility studies for spacecraft systems.

Li, Wenyan↗
NASA NTRSDate not supplied

Evaluating Novel Approaches for In Situ Analysis in the Search for Extraterrestrial Life

Universal approaches to detect extraterrestrial life are required to determine whether life exists outside of earth. A significant limitation of current detection strategies is the absence of a reliable, universal approach. They do not provide mechanisms to detect life that has evolved distinctly from life on Earth. We hypothesize that the most basic, essential features of life that can be detected are that they decrease their internal entropy at the expense of free energy obtained from their surroundings and that they produce heat associated with metabolic reactions. We propose that by using a thermodynamic analysis of the energy associated with these fundamental components of life, one can readily quantify the degree of free energy difference between life forms or their remnants and their abiotic surroundings. Analysis of the free energy entropy term (and thus structural complexity) and enthalpy term (as a manifestation of the energy release caused by metabolic reactions) may provide definitive detection of the presence of life. As a part of our analysis we review data available in the literature about the thermodynamics of microbial growth to assess the extent microbial metabolism and growth may contribute to negative entropy of maintenance (metabolism) and structural complexity. Additionally, we evaluate the different mechanisms by which structural complexity can be measured using calorimetry. An experimental framework is considered using concepts from previous work that could be used to further validate the calorimetric methods for life detection by potentially differentiating between life forms or their remnants from an abiotic surrounding. Results obtained demonstrate the applications of this approach and indicate that modification of a microcalorimetric technique has potential for incorporation into a space exploration platform as a life-detection payload.

Life Detection, Calorimetry↗
NASA NTRSDate not supplied

NASA Space Launch System Prepares for Key Hotfire Test Before Vehicle Integration

NASA this year is working toward the final major integrated hardware and avionics test for its Space Launch System (SLS), the agency’s new super heavy-lift vehicle to send large, strategic payloads to the Moon, Mars and beyond. As the backbone of the Artemis human lunar exploration program, Artemis I SLS operations will then shift to the launch site and integration for the inaugural mission. For this final major test of the first vehicle NASA has built exclusively for deep space exploration since the Saturn V, a NASA/Boeing/Aerojet Rocketdyne team will conduct the final core stage “green run” test at NASA's Stennis Space Center with a dramatic firing of all four core stage engines. This test will validate the operation of the stage structures, main propulsion system, engines, avionics, and software. Following data review, stage inspection, and refurbishment, the stage will be barged to NASA’s Kennedy Space Center to continue integration of the Artemis I launch vehicle. Already underway is assembly of the mission’s five-segment solid rocket boosters. The mission’s upper stage and spacecraft adapters also are staged at the launch site ready for integration. Even as the Artemis I SLS proceeds toward launch later this year, the Artemis II and Artemis III vehicles are coming together, with core stages, engines, boosters, upper stage, and payload accommodations in various stages of manufacturing and/or processing. Planning is also underway for additional core stages and a new, more powerful upper stage that will increase lunar payload mass. SLS is the anchor transportation leg of a plan for sustained human exploration of the Moon, including the first human landing later in the decade. This paper will discuss SLS progress to date and expected 2021 milestones.

Bruce R. Askins↗
NASA NTRSDate not supplied

Composite Materials Handbook 17 (CMH-17) Volume 5—Ceramic Matrix Composites

The intent of the Composite Materials Handbook‐17 (CMH‐17) Vol 5A—Ceramic Matrix Composites is that it will provide the information and guidance necessary to design, fabricate, and implement ceramic matrix composite components for commercial aircraft engines. The CMH-17 sponsor is the FAA (Federal Aviation Administration). This presentation describes the updating of the handbook, and covers the objectives and activities of the Working Groups that are preparing new content and revising existing text. The 5 Working Groups are: 1) Data Review, 2) Testing, 3) Materials & Processes, 4) Design and Analysis, and 5) Engine Applications. Goal: release Vol 5B in 2023.

Environmental barrier coating (EBC), Ceramic Matri↗
NASA NTRS2022

Robotics Verification and Validation Strategies for Perseverance Rover Sampling and Caching

The Mars 2020 Sampling and Caching Subsystem(SCS) is the most complex robotic system ever fielded on a MarsRover. It includes a 5 degree-of-freedom Robotic Arm, coringdrill, gas Dust Removal Tool, interfaces for two turret-mountedinstruments, and an Adaptive Caching Assembly (ACA). TheACA is itself a complex robotic system, containing hardware tosupport docking and bit exchange, a 3 degree-of-freedomSample Handling Assembly for manipulating sample tubes,storage for several drill bits and sample tubes, and mechanismsto support observing and sealing samples collected by the drill.To successfully verify and validate the SCS hardware andsoftware and its integration with the Mars 2020 flight systemseveral key strategies were employed.The SCS Verification and Validation (V&V) program utilizedmultiple test venues with tiered levels of fidelity. These includedsimulation and visualization software environments, low fidelitydevelopment testbeds, testbeds with high fidelity SCS hardwareand commercial off-the shelf avionics, integrated systemtestbeds with flight-like avionics, and environmental testbedscapable of simulating Martian surface temperature andpressure. Multiple units of each SCS hardware componentmoved fluidly between test venues to accomplish myriadstandalone and coordinated test objectives. Test preparationand executions were performed by a diverse team of engineerswith training and technical ownership tailored for individualexperience and role. Despite significant differences between testvenues, the SCS V&V team established efficient and consistentprocesses and tools for procedure development, test execution,and data review that enabled personnel, as well as technicalproducts such as sequences and parameter configurations, toflow between venues effectively. A series of benchmark testsprovided evidence of performance consistency as elements weretransferred between venues and as system capability evolved.This paper provides an overview of the SCS V&V program andexplores several overarching strategies that enabled successfuloperation in the face of unprecedented complexity. Keyoutcomes of the SCS validation effort are summarized, alongwith lessons learned and beneficial integrations of validationtool and process innovations into Mars surface operations.

Brooks, Sawyer↗
NASA NTRS1980

Review of Spectroscopic Data for Measurements of Stratospheric Species

Results and recommendations from a two day workshop are discussed. A review of the current status of experimental and theoretical spectroscopic data on molecules of stratospheric interest is given along with recommendations for additional research. Methods for disseminating new and existing data are also discussed.

Goldman, A.↗
NASA NTRS1981

Solar magnetic structure and the solar activity cycle review of observational data

Data on solar magnetism that may offer clues for understanding stellar magnetism in general were reviewed. Magnetic phenomena in the photosphere and low chromosphere, where the magnetic structure can be studied in detail, are discussed. Properties of the discrete magnetic elements and their extensions through the chromosphere and transition zone up to the corona are described. The structure and evolution of active regions and other structured aggregates of magnetic elements are considered.

Zwaan, C.↗