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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 505 records · Page 28

Effects of coronal disturbances on the ionization state of the solar wind

A theoretical investigation of the relationship between physical conditions in coronal disturbances and the ionization states of the resulting perturbed solar wind was conducted. Available measurements of active solar wind associated with solar flares often show an enhanced degree of ionization (e.g., Fe(+17)), implying that the measured solar wind material is flare-heated at its coronal source. In contrast, other active solar wind flows sometimes show anomalously low degrees of ionization (e.g., He(+)), implying that some solar material is expelled from the corona without ever reaching coronal temperatures. The effects of impulsive heat and/or momentum addition in the corona on the hydrodynamics and ionization state of the corona and solar wind were studied. One of the primary objectives of the current grant was the development of a software package suitable for: (1) generating models for the effects of impulsive heat and/or momentum deposition on plasma temperatures, densities and flow velocities; and (2) calculating the ionization state of the solar wind as a function of the location, duration and magnitude of heat and/or momentum deposition.

Withbroe, G. L.↗

Copper Alloy For High-Temperature Uses

Alloy of Cu/8Cr/4Nb (numbers indicate parts by atom percent) improved over older high-temperature copper-based alloys in that it offers enhanced high temperature strength, resistance to creep, and ductility while retaining most of thermal conductivity of pure copper; in addition, alloy does not become embrittled upon exposure to hydrogen at temperatures as high as 705 degrees C. Designed for use in presence of high heat fluxes and active cooling; for example, in heat exchangers in advanced aircraft and spacecraft engines, and other high-temperature applications in which there is need for such material. High conductivity and hardness of alloy exploited in welding electrodes and in high-voltage and high-current switches and other applications in which wear poses design problem.

Dreshfield, Robert L.↗

Characterization of Measurement Error Sources in Doppler Global Velocimetry

Doppler global velocimetry uses the absorption characteristics of iodine vapor to provide instantaneous three-component measurements of flow velocity within a plane defined by a laser light sheet. Although the technology is straightforward, its utilization as a flow diagnostics tool requires hardening of the optical system and careful attention to detail during data acquisition and processing if routine use in wind tunnel applications is to be achieved. A development program that reaches these goals is presented. Theoretical and experimental investigations were conducted on each technology element to determine methods that increase measurement accuracy and repeatability. Enhancements resulting from these investigations included methods to ensure iodine vapor calibration stability, single frequency operation of the laser and image alignment to sub-pixel accuracies. Methods were also developed to improve system calibration, and eliminate spatial variations of optical frequency in the laser output, spatial variations in optical transmissivity and perspective and optical distortions in the data images. Each of these enhancements is described and experimental examples given to illustrate the improved measurement performance obtained by the enhancement. The culmination of this investigation was the measured velocity profile of a rotating wheel resulting in a 1.75% error in the mean with a standard deviation of 0.5 m/s. Comparing measurements of a jet flow with corresponding Pitot measurements validated the use of these methods for flow field applications.

Meyers, James F.↗

Air Ground Integration Study

A simulation was conducted to examine the effect of shared air/ground authority when each is equipped with enhanced traffic- and conflict-alerting systems. The potential benefits of an advanced air traffic management (ATM) concept referred to as "free flight" include improved safety through enhanced conflict detection and resolution capabilities, increased flight-operations management, and better decision-making tools for air traffic controllers and flight crews. One element of the free-flight concept suggests shifting aircraft separation responsibility from air traffic controllers to flight crews, thereby creating an environment with "shared-separation" authority. During FY00. NASA, the Federal Aviation Administration (FAA), and the Volpe National Transportation Systems Center completed the first integrated, high-fidelity, real-time, human-in-the-loop simulation.

Lozito, Sandy↗

Computational Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for a Supersonic Aircraft Application

A computational investigation of an axisymmetric Dual Throat Nozzle concept has been conducted. This fluidic thrust-vectoring nozzle was designed with a recessed cavity to enhance the throat shifting technique for improved thrust vectoring. The structured-grid, unsteady Reynolds- Averaged Navier-Stokes flow solver PAB3D was used to guide the nozzle design and analyze performance. Nozzle design variables included extent of circumferential injection, cavity divergence angle, cavity length, and cavity convergence angle. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 1.89 to 10, with the fluidic injection flow rate equal to zero and up to 4 percent of the primary flow rate. The effect of a variable expansion ratio on nozzle performance over a range of freestream Mach numbers up to 2 was investigated. Results indicated that a 60 circumferential injection was a good compromise between large thrust vector angles and efficient internal nozzle performance. A cavity divergence angle greater than 10 was detrimental to thrust vector angle. Shortening the cavity length improved internal nozzle performance with a small penalty to thrust vector angle. Contrary to expectations, a variable expansion ratio did not improve thrust efficiency at the flight conditions investigated.

Deere, Karen A.↗

The EXIST Mission Concept Study

EXIST is a mission designed to find and study black holes (BHs) over a wide range of environments and masses, including: 1) BHs accreting from binary companions or dense molecular clouds throughout our Galaxy and the Local Group, 2) supermassive black holes (SMBHs) lying dormant in galaxies that reveal their existence by disrupting passing stars, and 3) SMBHs that are hidden from our view at lower energies due to obscuration by the gas that they accrete. 4) the birth of stellar mass BHs which is accompanied by long cosmic gamma-ray bursts (GRBs) which are seen several times a day and may be associated with the earliest stars to form in the Universe. EXIST will provide an order of magnitude increase in sensitivity and angular resolution as well as greater spectral resolution and bandwidth compared with earlier hard X-ray survey telescopes. With an onboard optical-infra red (IR) telescope, EXIST will measure the spectra and redshifts of GRBs and their utility as cosmological probes of the highest z universe and epoch of reionization. The mission would retain its primary goal of being the Black Hole Finder Probe in the Beyond Einstein Program. However, the new design for EXIST proposed to be studied here represents a significant advance from its previous incarnation as presented to BEPAC. The mission is now less than half the total mass, would be launched on the smallest EELV available (Atlas V-401) for a Medium Class mission, and most importantly includes a two-telescope complement that is ideally suited for the study of both obscured and very distant BHs. EXIST retains its very wide field hard X-ray imaging High Energy Telescope (HET) as the primary instrument, now with improved angular and spectral resolution, and in a more compact payload that allows occasional rapid slews for immediate optical/IR imaging and spectra of GRBs and AGN as well as enhanced hard X-ray spectra and timing with pointed observations. The mission would conduct a 2 year full sky survey in scanning mode, interrupted for several orbits per day by GRB follow-ups, followed by a combined pointing-scanning mission phase for optical/IR spectroscopy and redshifts for the large AGN sample found in the survey as well as GRBs and LSST transients. A Team of university, NASA, and industry investigators will conduct the study to determine the full sensitivity and capabilities of this new configuration for EXIST. It will build on the extensive studies of the prior design for the mission and the HET and will incorporate the optical/IR telescope (hereafter IRT) now fully developed by our ITT partner for the NextView Commercial Remote Sensing mission (early 2008 launch) with a focal plane to be developed at GSFC based in part on JWST/NIRSPEC designs. No new technology is needed for either the IRT or HET instruments. The study will pay close attention to full mission cost and present a design for the Decadal Survey Workshop to ensure this even more capable EXIST mission is once again part of the next Decadal Survey.

Fishman, Gerald J.↗

Advanced Single-Aisle Transport Propulsion Design Options Revisited

Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turbofans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turbofan fan pressure ratio trade study using updated analysis methodology and assumptions. The changes incorporated have decreased the optimum fan pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum fan pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.

Guynn, Mark D.↗

Evaluation of Solid Rocket Motor Component Data Using a Commercially Available Statistical Software Package

Commercially available software packages today allow users to quickly perform the routine evaluations of (1) descriptive statistics to numerically and graphically summarize both sample and population data, (2) inferential statistics that draws conclusions about a given population from samples taken of it, (3) probability determinations that can be used to generate estimates of reliability allowables, and finally (4) the setup of designed experiments and analysis of their data to identify significant material and process characteristics for application in both product manufacturing and performance enhancement. This paper presents examples of analysis and experimental design work that has been conducted using Statgraphics®(Registered Trademark) statistical software to obtain useful information with regard to solid rocket motor propellants and internal insulation material. Data were obtained from a number of programs (Shuttle, Constellation, and Space Launch System) and sources that include solid propellant burn rate strands, tensile specimens, sub‐scale test motors, full‐scale operational motors, rubber insulation specimens, and sub‐scale rubber insulation analog samples. Besides facilitating the experimental design process to yield meaningful results, statistical software has demonstrated its ability to quickly perform complex data analyses and yield significant findings that might otherwise have gone unnoticed. One caveat to these successes is that useful results not only derive from the inherent power of the software package, but also from the skill and understanding of the data analyst.

Stefanski, Philip L.↗

Multifunctional Polymers and Composites for Aerospace Applications

System needs and challenges for commercial aviation and space exploration are constantly changing. Multifunctional materials are ideal for aerospace applications because their integration into structural components has potential to not only improve efficiency, but it can also increase payload and mission capabilities without the burden of significant additions to mass and volume. Multi-constituent materials will play an important role in enabling structures with the potential to demonstrate true multi-functionality; however, modifications to many mature polymer processing methods may be necessary. This presentation will cover multifunctional materials development efforts underway at the NASA Glenn Research Center related to formulating and characterizing novel electrical insulation for high voltage aircraft. Incorporating functionality into the reinforcement material is another materials development technique that will be discussed, which includes braiding with hybrid fibers to enhance toughness in composite structures, stitching with carbon nanotube yarns to make durable electrically conductive textiles, and treating fabrics with shear thickening fluid suspensions to produce impact-resistant inflatable habitats.

multi-functional composites↗

Unified Analysis of Aerospace Structures through Implementation of Rapid Tools into a Stress Framework

Rapid structural analysis tools have become an important part of the design cycle for aerospace companies for the last several decades. As these tools have been developed over time, there is often little consideration for shared software infrastructure between the tools, which makes design and analysis cumbersome due to a lack of commonality in input and output data and reporting, as well as poor traceability of results. Under the Rapid Tools task of the Advanced Composites Consortium (ACC), four aerospace tools were recently implemented or enhanced in the HyperSizer stress framework and then evaluated by this consortium of industry and government organizations. The framework provides an automated software environment for executing the rapid tools for analysis and sizing, quantifying margins of safety for thousands of load cases, and generating reports in support of FAA certification. This paper describes the process by which the tools were enhanced or implemented in the stress framework under the ACC project, and the evaluation conducted by industry consortium members.

Craig S Collier↗

The impact of increasing stratospheric radiative damping on the quasi-biennial oscillation period

Stratospheric radiative damping increases as atmospheric carbon dioxide concentration rises. We use the one-dimensional mechanistic models of the quasi-biennial oscillation (QBO) to conduct sensitivity experiments and find that the simulated QBO period shortens due to the enhancing of radiative damping in the stratosphere. This result suggests that increasing stratospheric radiative damping due to rising CO2 may play a role in determining the QBO period in a warming climate along with wave momentum flux entering the stratosphere and tropical vertical residual velocity, both of which also respond to increasing CO2.

Stratospheric Radiative Damping↗

DEVELOP’s Approach to Experiential Learning

The NASA DEVELOP Program addresses environmental decision making needs and geoscience workforce development through 10-week feasibility studies that apply Earth observations to environmental issues at hand. The program builds capacity to use geospatial information in both its participants (students, recent graduates, early career professionals, and transitioning career professionals) and partner organizations (federal agencies, state & local governments, non-profits, and private industry). This is accomplished through a structured project execution model that provides opportunities for participants to have autonomy, learn “on the job,” and gain new skillsets for working with remote sensing data. A pipeline of leadership positions enhances opportunities for individuals engaged in the program to get hands-on experience conducting data analyses, communicating their work, leading technical projects, and building their knowledge bank of Earth-observing satellite capabilities. These skillsets and knowledge are then transferred to partners through the projects. This panel contribution will introduce the DEVELOP model, highlight experiences of participants, and share the program’s insights into good practices for effective experiential learning.

Capacity Building↗

Space technology research plans

Development of new technologies is the primary purpose of the Office of Aeronautics and Space Technology (OAST). OAST's mission includes the following two goals: (1) to conduct research to provide fundamental understanding, develop advanced technology and promote technology transfer to assure U.S. preeminence in aeronautics and to enhance and/or enable future civil space missions: and (2) to provide unique facilities and technical expertise to support national aerospace needs. OAST includes both NASA Headquarters operations as well as programmatic and institutional management of the Ames Research Center, the Langley Research Center and the Lewis Research Center. In addition. a considerable portion of OAST's Space R&T Program is conducted through the flight and science program field centers of NASA. Within OAST, the Space Technology Directorate is responsible for the planning and implementation of the NASA Space Research and Technology Program. The Space Technology Directorate's mission is 'to assure that OAST shall provide technology for future civil space missions and provide a base of research and technology capabilities to serve all national space goals.' Accomplishing this mission entails the following objectives: y Identify, develop, validate and transfer technology to: (1) increase mission safety and reliability; (2) reduce flight program development and operations costs; (3) enhance mission performance; and (4) enable new missions. Provide the capability to: (1) advance technology in critical disciplines; and (2) respond to unanticipated mission needs. In-space experiments are an integral part of OAST's program and provides for experimental studies, development and support for in-space flight research and validation of advanced space technologies. Conducting technology experiments in space is a valuable and cost effective way to introduce advanced technologies into flight programs. These flight experiments support both the R&T base and the focussed programs within OAST.

Hook, W. Ray↗

Visual enhancements in pick-and-place tasks - Human operators controlling a simulated cylindrical manipulator

A teleoperation simulator has been constructed with vector display system, joysticks, and a simulated cylindrical manipulator, in order to quantitatively evaluate various display conditions. The first of two experiments thus conducted investigated the effects of perspective parameter variations on human operators' pick-and-place performance, using a monoscopic perspective display. The second experiment involved visual enhancements of the monoscopic perspective display, by adding a grid and reference lines, by comparison with visual enhancements of a stereoscopic display; results indicate that stereoscopy generally permits superior pick-and-place performance, but that monoscopy nevertheless allows equivalent performance when defined with appropriate perspective parameter values and adequate visual enhancements.

Kim, Won S.↗

Evaluation of the usefulness of various simulation technology options for TERPS enhancement

Current approved terminal instrument procedures (TERPS) do not permit the full exploitation of the helicopter's unique flying characteristics. Enhanced TERPS need to be developed for a host of non-standard landing sites and navigation aids. Precision navigation systems such as microwave landing systems (MLS) and the Global Positioning System (GPS) open the possibility of curved paths, steep glide slopes, and decelerating helicopter approaches. This study evaluated the feasibility, benefits, and liabilities of using helicopter cockpit simulators in place of flight testing to develop enhanced TERPS criteria for non-standard flight profiles and navigation equipment. Near-term (2 to 5 year) requirements for conducting simulator studies to verify that they produce suitable data comparable to that obtained from previous flight tests are discussed. The long-term (5 to 10 year) research and development requirements to provide necessary modeling for continued simulator-based testing to develop enhanced TERPS criteria are also outlined.

Phatak, A. V.↗

NASA Near Earth Network (NEN) DVB-S2 Demonstration Testing for Enhancing Data Rates for CubeSat/SmallSat Missions

National Aeronautics and Space Administration (NASA) CubeSat/SmallSat missions are expected to grow rapidly in the next decade. As the number of spacecraft on a ground network grows, employing higher data rates could reduce loading by reducing the contact time per day required. CubeSats also need to communicate directly to earth from space from longer distances than low earth orbit (LEO). These challenges motivate the need for bandwidth and power efficient modulation and coding techniques. Today, Digital Video Broadcast, Satellite Second Generation (DVB-S2) is a communications standard for larger satellites. DVB-S2 uses power and bandwidth efficient modulation and coding techniques to deliver performance approaching Radio Frequency (RF) channel theoretical limits. NASA’s Near Earth Network (NEN) conducted a demonstration test at the Wallops Flight Facility in spring of 2019 for CubeSat/SmallSat missions for enhancing data rate performance in NASA’s S-band 5 MHz channel. The goal is to upgrade NEN with DVB-S2 to increase science data return and enable greater numbers of CubeSats. This paper presents the NEN DVB-S2 demonstration testing objectives and performance measurement results. Results of the demonstration testing are compared with evolving SmallSat/CubeSat radios. DVB-S2 S-band transmitter development concepts for SmallSats/CubeSats and use of DVB-S2 by future missions are discussed.

Wong, Yen↗

Composite-Based High Performance Electroactive Polymers For Remotely Controlled Mechanical Manipulations in NASA Applications

This program supported investigation of an all-polymer percolative composite which exhibits very high dielectric constant (less than 7,000). The experimental results show that the dielectric behavior of this new class of percolative composites follows the prediction of the percolation theory and the analysis of the conductive percolation phenomena. The very high dielectric constant of the all-polymer composites which are also very flexible and possess elastic modulus not very much different from that of the insulation polymer matrix makes it possible to induce a high electromechanical response under a much reduced electric field (a strain of 2.65% with an elastic energy density of 0.18 J/cu cm can be achieved under a field of 16 MV/m). Data analysis also suggests that in these composites, the non-uniform local field distribution as well as interface effects can significantly enhance the strain responses. Furthermore, the experimental data as well as the data analysis indicate that the conduction loss in these composites will not affect the strain hysteresis.

Zhang, Q. M.↗

Intra-EVA Space-to-Ground Interactions when Conducting Scientific Fieldwork Under Simulated Mars Mission Constraints

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.

Beaton, Kara H.↗