SEARCH · Engineering Papers

Results for “support effects”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49

All sources NASA NTRS DOE OSTI

NASA NTRS1974

Study of roles of remote manipulator systems and EVA for shuttle mission support, volume 1

Alternate extravehicular activity (EVA) and remote manipulator system (RMS) configurations were examined for their relative effectiveness in performing an array of representative shuttle and payload support tasks. Initially a comprehensive analysis was performed of payload and shuttle support missions required to be conducted exterior to a pressurized inclosure. A set of task selection criteria was established, and study tasks were identified. The EVA and RMS modes were evaluated according to their applicability for each task and task condition. The results are summarized in tabular form, showing the modes which are chosen as most effective or as feasible for each task/condition. Conclusions concerning the requirements and recommendations for each mode are presented.

Malone, T. B.↗

NASA NTRS1972

Subsonic and supersonic static aerodynamic characteristics of a family of bulbous base cones measured with a magnetic suspension and balance system

Results of subsonic and supersonic wind-tunnel tests with a magnetic balance and suspension system on a family of bulbous based cone configurations are presented. At subsonic speeds the base flow and separation characteristics of these configurations is shown to have a pronounced effect on the static data. Results obtained with the presence of a dummy sting are compared with support interference free data. Support interference is shown to have a substantial effect on the measured aerodynamic coefficient.

Vlajinac, M.↗

NASA NTRS2017

Autonomous, Context-Sensitive, Task Management Systems and Decision Support Tools I: Human-Autonomy Teaming Fundamentals and State of the Art

Recent advances in artificial intelligence, machine learning, data mining and extraction, and especially in sensor technology have resulted in the availability of a vast amount of digital data and information and the development of advanced automated reasoners. This creates the opportunity for the development of a robust dynamic task manager and decision support tool that is context sensitive and integrates information from a wide array of on-board and off aircraft sourcesa tool that monitors systems and the overall flight situation, anticipates information needs, prioritizes tasks appropriately, keeps pilots well informed, and is nimble and able to adapt to changing circumstances. This is the first of two companion reports exploring issues associated with autonomous, context-sensitive, task management and decision support tools. In the first report, we explore fundamental issues associated with the development of an integrated, dynamic, flight information and automation management system. We discuss human factors issues pertaining to information automation and review the current state of the art of pilot information management and decision support tools. We also explore how effective human-human team behavior and expectations could be extended to teams involving humans and automation or autonomous systems.

context-sensitive↗

NASA NTRS2016

Graphene Field Effect Transistor for Radiation Detection

The present invention relates to a graphene field effect transistor-based radiation sensor for use in a variety of radiation detection applications, including manned spaceflight missions. The sensing mechanism of the radiation sensor is based on the high sensitivity of graphene in the local change of electric field that can result from the interaction of ionizing radiation with a gated undoped silicon absorber serving as the supporting substrate in the graphene field effect transistor. The radiation sensor has low power and high sensitivity, a flexible structure, and a wide temperature range, and can be used in a variety of applications, particularly in space missions for human exploration.

Li, Mary J.↗

NASA NTRS2002

Light, plants, and power for life support on Mars

Regardless of how well other growing conditions are optimized, crop yields will be limited by the available light up to saturation irradiances. Considering the various factors of clouds on Earth, dust storms on Mars, thickness of atmosphere, and relative orbits, there is roughly 2/3 as much light averaged annually on Mars as on Earth. On Mars, however, crops must be grown under controlled conditions (greenhouse or growth rooms). Because there presently exists no material that can safely be pressurized, insulated, and resist hazards of puncture and deterioration to create life support systems on Mars while allowing for sufficient natural light penetration as well, artificial light will have to be supplied. If high irradiance is provided for long daily photoperiods, the growing area can be reduced by a factor of 3-4 relative to the most efficient irradiance for cereal crops such as wheat and rice, and perhaps for some other crops. Only a small penalty in required energy will be incurred by such optimization. To obtain maximum yields, crops must be chosen that can utilize high irradiances. Factors that increase ability to convert high light into increased productivity include canopy architecture, high-yield index (harvest index), and long-day or day-neutral flowering and tuberization responses. Prototype life support systems such as Bios-3 in Siberia or the Mars on Earth Project need to be undertaken to test and further refine systems and parameters.

Non-NASA Center↗

NASA NTRS1999

Neocytolysis contributes to the anemia of renal disease

Neocytolysis is a recently described physiological process affecting the selective hemolysis of young red blood cells in circumstances of plethora. Erythropoietin (EPO) depression appears to initiate the process, providing the rationale to investigate its contributions to the anemia of renal disease. When EPO therapy was withheld, four of five stable hemodialysis patients showed chromium 51 (51Cr)-red cell survival patterns indicative of neocytolysis; red cell survival was short in the first 9 days, then normalized. Two of these four patients received oral 13C-glycine and 15N-glycine, and there was a suggestion of pathological isotope enrichment of stool porphyrins when EPO therapy was held, again supporting selective hemolysis of newly released red cells that take up the isotope (one patient had chronic hemolysis indicated by isotope studies of blood and stool). Thus, neocytolysis can contribute to the anemia of renal disease and explain some unresolved issues about such anemia. One implication is the prediction that intravenous bolus EPO therapy is metabolically and economically inefficient compared with lower doses administered more frequently subcutaneously.

Non-NASA Center↗

NASA NTRS1998

Fiber-Supported Droplet Combustion Experiment-2

A major portion of the energy produced in the world today comes from the burning of liquid hydrocarbon fuels in the form of droplets. Understanding the fundamental physical processes involved in droplet combustion is not only important in energy production but also in propulsion, in the mitigation of combustion-generated pollution, and in the control of the fire hazards associated with handling liquid combustibles. Microgravity makes spherically symmetric combustion possible, allowing investigators to easily validate their droplet models without the complicating effects of gravity. The Fiber-Supported Droplet Combustion (FSDC-2) investigation was conducted in the Microgravity Glovebox facility of the shuttles' Spacelab during the reflight of the Microgravity Science Laboratory (MSL- 1R) on STS-94 in July 1997. FSDC-2 studied fundamental phenomena related to liquid fuel droplet combustion in air. Pure fuels and mixtures of fuels were burned as isolated single and duo droplets with and without forced air convection. FSDC-2 is sponsored by the NASA Lewis Research Center, whose researchers are working in cooperation with several investigators from industry and academia. The rate at which a droplet burns is important in many commercial applications. The classical theory of droplet burning assumes that, for an isolated, spherically symmetric, single-fuel droplet, the gas-phase combustion processes are much faster than the droplet surface regression rate and that the liquid phase is at a uniform temperature equal to the boiling point. Recent, more advanced models predict that both the liquid and gas phases are unsteady during a substantial portion of the droplet's burning history, thus affecting the instantaneous and average burning rates, and that flame radiation is a dominant mechanism that can extinguish flames in a microgravity environment. FSDC-2 has provided well-defined, symmetric droplet burning data including radiative emissions to validate these theoretical models for heptane, decane, ethanol, and methanol fuels. Since most commercial combustion systems burn droplets in a convective environment, data were obtained without and with convective flow over the burning droplet (see the following photos).

Colantonio, Renato O.↗

NASA NTRS2006

Shuttle Damage/Repair from the Perspective of Hypersonic Boundary Layer Transition - Experimental Results

An overview is provided of the experimental wind tunnel program conducted at the NASA Langley Research Center Aerothermodynamics Laboratory in support of an agency-wide effort to prepare the Shuttle Orbiter for Return-to-Flight. The effect of an isolated protuberance and an isolated rectangular cavity on hypersonic boundary layer transition onset on the windward surface of the Shuttle Orbiter has been experimentally characterized. These experimental studies were initiated to provide a protuberance and cavity effects database for developing hypersonic transition criteria to support on-orbit disposition of thermal protection system damage or repair. In addition, a synergistic experimental investigation was undertaken to assess the impact of an isolated mass-flow entrainment source (simulating pyrolysis/outgassing from a proposed tile repair material) on boundary layer transition. A brief review of the relevant literature regarding hypersonic boundary layer transition induced from cavities and localized mass addition from ablation is presented. Boundary layer transition results were obtained using 0.0075-scale Orbiter models with simulated tile damage (rectangular cavities) of varying length, width, and depth and simulated tile damage or repair (protuberances) of varying height. Cavity and mass addition effects were assessed at a fixed location (x/L = 0.3) along the model centerline in a region of near zero pressure gradient. Cavity length-to-depth ratio was systematically varied from 2.5 to 17.7 and length-to-width ratio of 1 to 8.5. Cavity depth-to-local boundary layer thickness ranged from 0.5 to 4.8. Protuberances were located at several sites along the centerline and port/starboard attachment lines along the chine and wing leading edge. Protuberance height-to-boundary layer thickness was varied from approximately 0.2 to 1.1. Global heat transfer images and heating distributions of the Orbiter windward surface using phosphor thermography were used to infer the state of the boundary layer (laminar, transitional, or turbulent). Test parametrics include angles-of-attack of 30 deg and 40 deg, sideslip angle of 0 deg, freestream Reynolds numbers from 0.02x106 to 7.3x106 per foot, edge-to-wall temperature ratio from 0.4 to 0.8, and normal shock density ratios of approximately 5.3, 6.0, and 12 in Mach 6 air, Mach 10 air, and Mach 6 CF4, respectively. Testing to simulate the effects of ablation from a proposed tile repair concept indicated that transition was not a concern. The experimental protuberance and cavity databases highlighted in this report were used to formulate boundary layer transition correlations that were an integral part of an analytical process to disposition observed Orbiter TPS damage during STS- 114.

Horvath, Thomas J.↗

NASA NTRS1986

NASA's life sciences program

NASA space missions from the Mercury through the Shuttle program have provided successively more data on the ability of humans to function in space for progressively longer periods of time. The Skylab program encouraged cooperation between medical and engineering personnel in the design of space suits, diet, food preparation, and cleanliness procedures and equipment, and the man-machine interface. Research is now concentrated on supporting man in space, evaluating the effects of the microgravity environment on humans, and modeling encounters with extraterrestrial life and the effects of human activities on terrestrial biota. Current levels of understanding of the physiological causes of human health problems produced by long-duration spaceflight are summarized. Experiments planned for the Shuttle, Spacelab, and the Space Station are outlined, noting the long-term goal of configuring the Space Station so that only food and hydrazine are needed to complete the life support system cycle.

Soffen, Gerald A.↗

NASA NTRS2004

Turnaround Time Modeling for Conceptual Rocket Engines

Recent years have brought about a paradigm shift within NASA and the Space Launch Community regarding the performance of conceptual design. Reliability, maintainability, supportability, and operability are no longer effects of design; they have moved to the forefront and are affecting design. A primary focus of this shift has been a planned decrease in vehicle turnaround time. Potentials for instituting this decrease include attacking the issues of removing, refurbishing, and replacing the engines after each flight. less, it is important to understand the operational affects of an engine on turnaround time, ground support personnel and equipment. One tool for visualizing this relationship involves the creation of a Discrete Event Simulation (DES). A DES model can be used to run a series of trade studies to determine if the engine is meeting its requirements, and, if not, what can be altered to bring it into compliance. Using DES, it is possible to look at the ways in which labor requirements, parallel maintenance versus serial maintenance, and maintenance scheduling affect the overall turnaround time. A detailed DES model of the Space Shuttle Main Engines (SSME) has been developed. Trades may be performed using the SSME Processing Model to see where maintenance bottlenecks occur, what the benefits (if any) are of increasing the numbers of personnel, or the number and location of facilities, in addition to trades previously mentioned, all with the goal of optimizing the operational turnaround time and minimizing operational cost. The SSME Processing Model was developed in such a way that it can easily be used as a foundation for developing DES models of other operational or developmental reusable engines. Performing a DES on a developmental engine during the conceptual phase makes it easier to affect the design and make changes to bring about a decrease in turnaround time and costs.

Nix, Michael↗

NASA NTRS2003

Volatile-rich Crater Interior Deposits on Mars: An Energy Balance Model of Modification

Several craters on Mars are partially filled by material emplaced by post-impact processes. Populations of such craters include those in the circumsouth polar cap region, in Arabia Terra, associated with the Medusae Fossae Formation, and in the northern lowlands proximal to the north polar cap. In this study, crater fill material refers to an interior mound, generally separated from the interior walls of the crater by a trough that may be continuous along the crater s circumference (i.e. a ring-shaped trough), or may only partially contact the crater walls (i.e. a crescent-shaped trough). The fill deposit is frequently off-center from the crater center and may be asymmetric, (i.e. not circular) in plan view shape. Here we test the hypothesis that asymmetries in volatile fill shape, profile, and center-location within a crater result from asymmetries in local energy balance within the crater due mainly to variation of solar insolation and radiative effects of the crater walls over the crater interior. We first focus on Korolev crater in the northern lowlands. We can then apply this model to other craters in different regions. If asymmetry in morphology and location of crater fill are consistent with radiative-dominated asymmetries in energy budget within the crater, then 1) the volatile-rich composition of the fill is supported (this process should not be effective at shaping volcanic or sedimentary deposits), and 2) the dominant factor determining the observed shape of volatile-rich crater fill is the local radiative energy budget within the crater (and erosive processes such as eolian deflation are not necessary).

Russell, Patrick S.↗

NASA NTRS1991

Enroute flight planning: Evaluating design concepts for the development of cooperative problem-solving concepts

The goals of this research were to develop design concepts to support the task of enroute flight planning. And within this context, to explore and evaluate general design concepts and principles to guide the development of cooperative problem solving systems. A detailed model is to be developed of the cognitive processes involved in flight planning. Included in this model will be the identification of individual differences of subjects. Of particular interest will be differences between pilots and dispatchers. The effect will be studied of the effect on performance of tools that support planning at different levels of abstraction. In order to conduct this research, the Flight Planning Testbed (FPT) was developed, a fully functional testbed environment for studying advanced design concepts for tools to aid in flight planning.

Smith, Philip J.↗

NASA NTRS2004

Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

Li, Jing↗

NASA NTRS2000

Preliminary development and evaluation of an algae-based air regeneration system

The potential of air regeneration system based on the growth of microalgae on the surface of porous ceramic tubes is evaluated. The algae have been maintained in the system for extended periods, up to 360 days. Preliminary measurements of the photosynthetic capacity have been made for Chlorella vulgaris (UTEX 259), Neospongiococcum punctatum (UTEX 786), Stichococcus sp., and Gloeocapsa sp. Under standard test conditions (photosynthetic photon flux approximately 66 micromoles m-2 s-1, initial CO2 concentration approximately 450 micromoles mol-1), mature tubes remove up to 0.2 micromoles of CO2 per tube per minute. The rate of removal increases with photon flux up to at least 225 micromoles m-2 s-1 (PPF); peak rates of 0.35 micromoles of CO2 per tube per minute have been achieved with Chlorella vulgaris. These rates correspond to between 120 and 210 micromoles of CO2 removed per square meter of projected area per minute.

Non-NASA Center↗

NASA NTRS1988

Exploring the limits of crop productivity. I. Photosynthetic efficiency of wheat in high irradiance environments

The long-term vegetative and reproductive growth rates of a wheat crop (Triticum aestivum L.) were determined in three separate studies (24, 45, and 79 days) in response to a wide range of photosynthetic photon fluxes (PPF, 400-2080 micromoles per square meter per second; 22-150 moles per square meter per day; 16-20 hour photoperiod) in a near-optimum, controlled-environment. The CO2 concentration was elevated to 1200 micromoles per mole, and water and nutrients were supplied by liquid hydroponic culture. An unusually high plant density (2000 plants per square meter) was used to obtain high yields. Crop growth rate and grain yield reached 138 and 60 grams per square meter per day, respectively; both continued to increase up to the highest integrated daily PPF level, which was three times greater than a typical daily flux in the field. The conversion efficiency of photosynthesis (energy in biomass/energy in photosynthetic photons) was over 10% at low PPF but decreased to 7% as PPF increased. Harvest index increased from 41 to 44% as PPF increased. Yield components for primary, secondary, and tertiary culms were analyzed separately. Tillering produced up to 7000 heads per square meter at the highest PPF level. Primary and secondary culms were 10% more efficient (higher harvest index) than tertiary culms; hence cultural, environmental, or genetic changes that increase the percentage of primary and secondary culms might increase harvest index and thus grain yield. Wheat is physiologically and genetically capable of much higher productivity and photosynthetic efficiency than has been recorded in a field environment.

NASA Discipline Number 61-10↗

NASA NTRS1989

8-OH-DPAT suppresses vomiting in the cat elicited by motion, cisplatin or xylazine

Vomiting was suppressed in cats pretreated with 8-OH-DPAT and then challenged with an emetic stimulus; motion, xylazine or cisplatin. The antiemetic effect is likely due to stimulation of postsynaptic serotonin-1A receptors. The most parsimonious explanation is that it acts at a convergent structure, presumably at or near the vomiting center. If so, 8-OH-DPAT may block emesis elicited by virtually any other stimulus. A supplementary experiment revealed that lorazepam suppressed motion sickness at a dose that produced ataxia, but did not suppress xylazine-induced emesis. These results do not support the possibility that the antiemetic effects of 8-OH-DPAT were the result of anxiolytic activity.

Lucot, James B.↗

NASA NTRS2005

Towards G2G: Systems of Technology Database Systems

We present an approach and methodology for developing Government-to-Government (G2G) Systems of Technology Database Systems. G2G will deliver technologies for distributed and remote integration of technology data for internal use in analysis and planning as well as for external communications. G2G enables NASA managers, engineers, operational teams and information systems to "compose" technology roadmaps and plans by selecting, combining, extending, specializing and modifying components of technology database systems. G2G will interoperate information and knowledge that is distributed across organizational entities involved that is ideal for NASA future Exploration Enterprise. Key contributions of the G2G system will include the creation of an integrated approach to sustain effective management of technology investments that supports the ability of various technology database systems to be independently managed. The integration technology will comply with emerging open standards. Applications can thus be customized for local needs while enabling an integrated management of technology approach that serves the global needs of NASA. The G2G capabilities will use NASA s breakthrough in database "composition" and integration technology, will use and advance emerging open standards, and will use commercial information technologies to enable effective System of Technology Database systems.

Maluf, David A.↗

NASA NTRS1983

Large space structures raise testing challenges

The testing approaches and techniques necessary for combined ground and space verification for large space structures (LSS) to be deployed and assembled in space are explored. The size of LSS precludes full ground tests, thereby requiring assemblies, components, and their interactions to be examined on orbit. Ground tests involving drop tests and zero-g aircraft flights can be performed with scale models, but need computational compensation to eliminate gravitational and torque effects that do not occur in space. Structural rigidity also varies from ground to space, and can partly be accounted for in ground tests by using cable supports, although numerical modelling must remove the effects of the cables' presence. Long-term funding is recommended for on-orbit tests of components in order to build a data base for later testing and actual construction of LSS.

Hanks, B. R.↗