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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Feasibility of water injection into the turbine coolant to permit gas turbine contingency power for helicopter application

A system which would allow a substantially increased output from a turboshaft engine for brief periods in emergency situations with little or no loss of turbine stress rupture life is proposed and studied analytically. The increased engine output is obtained by overtemperaturing the turbine; however, the temperature of the compressor bleed air used for hot section cooling is lowered by injecting and evaporating water. This decrease in cooling air temperature can offset the effect of increased gas temperature and increased shaft speed and thus keep turbine blade stress rupture life constant. The analysis utilized the NASA-Navy-Engine-Program or NNEP computer code to model the turboshaft engine in both design and off-design modes. This report is concerned with the effect of the proposed method of power augmentation on the engine cycle and turbine components. A simple cycle turboshaft engine with a 16:1 pressure ratio and a 1533 K (2760 R) turbine inlet temperature operating at sea level static conditions was studied to determine the possible power increase and the effect on turbine stress rupture life that could be expected using the proposed emergency cooling scheme. The analysis showed a 54 percent increse in output power can be achieved with no loss in gas generator turbine stress rupture life. A 231 K (415 F) rise in turbine inlet temperature is required for this level of augmentation. The required water flow rate was found to be .0109 kg water per kg of engine air flow.

Vanfossen, G. J.↗
NASA NTRS1983

Packet telemetry and packet telecommand - The new generation of spacecraft data handling techniques

Because of rising costs and reduced reliability of spacecraft and ground network hardware and software customization, standardization Packet Telemetry and Packet Telecommand concepts are emerging as viable alternatives. Autonomous packets of data, within each concept, which are created within ground and space application processes through the use of formatting techniques, are switched end-to-end through the space data network to their destination application processes through the use of standard transfer protocols. This process may result in facilitating a high degree of automation and interoperability because of completely mission-independent-designed intermediate data networks. The adoption of an international guideline for future space telemetry formatting of the Packet Telemetry concept, and the advancement of the NASA-ESA Working Group's Packet Telecommand concept to a level of maturity parallel to the of Packet Telemetry are the goals of the Consultative Committee for Space Data Systems. Both the Packet Telemetry and Packet Telecommand concepts are reviewed.

Hooke, A. J.↗
NASA NTRS1985

Results of studies on advanced winged space transportation systems

Various winged spaceplane concepts which appear viable as the post-Shuttle generation of launch vehicles are reviewed. The designs all yield improvements in size and mass compared to the STS, provided certain emerging technologies are successfully applied. Single-stage-to-orbit (SSTO) vehicles would burn LOX/LH fuels in SSME-derived engines with two position nozzles. SSTO could be realized in either vertical or horizontal take-off configurations, but all would have 29,500 kg payload capacities and horizontal landing capabilities. Consideration is given to alternative fuels, the effects of adding air-breathing engines, various ways of attaching and deploying payloads, containing the fuels and providing thermal protection during reentry. It is found that similar technology advances are needed for all the concepts.

Arrington, J. P.↗
NASA NTRS2009

Chemochromic Hydrogen Leak Detectors

At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or other failures in those systems. In another type of envisioned application, chemochromic detectors of this type could be optoelectronically instrumented for monitoring to provide measured digital indications of color changes indicative of the presence of hydrogen.

Roberson, Luke↗
NASA NTRS2015

Cascade Distillation System Design for Safety and Mission Assurance

Per the NASA Human Health, Life Support and Habitation System Technology Area 06 report "crewed missions venturing beyond Low-Earth Orbit (LEO) will require technologies with improved reliability, reduced mass, self-sufficiency, and minimal logistical needs as an emergency or quick-return option will not be feasible".1 To meet this need, the development team of the second generation Cascade Distillation System (CDS 2.0) chose a development approach that explicitly incorporate consideration of safety, mission assurance, and autonomy. The CDS 2.0 preliminary design focused on establishing a functional baseline that meets the CDS core capabilities and performance. The critical design phase is now focused on incorporating features through a deliberative process of establishing the systems failure modes and effects, identifying mitigation strategies, and evaluating the merit of the proposed actions through analysis and test. This paper details results of this effort on the CDS 2.0 design.

Sarguisingh, Miriam↗
NASA NTRSDate not supplied

Integration of Advanced Structures and Materials Technologies for a Robust Lunar Habitat

NASA’s Artemis program plans to have a sustainable lunar base deployed on the Moon by 2028. The base calls for a foundation surface habitat that can support a crew of four members for a minimum mission duration of 28-days. The lack of a magnetic field and significant lunar atmosphere extends the lifetime of secondary radiation emitted from metallic structures, which is a health hazard for exposed astronauts. Integration of non-metallic structural materials into surface habitat design may alleviate some of these concerns. Additionally, it is favorable for the structure to be collapsible for transportation to optimize payload volume, mass efficiency, and monetary constraints. As a result, inflatable structures are being investigated due to their improved packing efficiency at launch, optimal mass-to-volume ratio, and large surface area that can efficiently disperse structural loads and heat. Currently, only two inflatable airlocks have been deployed in space. Thus, there is a significant need to advance technologies associated with inflatable structures to provide greater options for future missions, i.e., Artemis and beyond. This study focused on the inflatable lunar habitat applications of emerging NASA Langley Research Center (LaRC) technologies and their required development steps to become space qualified. The Bowling Habitat architecture was generated from 13 of these NASA LaRC technologies, five of which were deemed critical, five determined as enhancing technologies, and three were classified as transformational technologies for the Artemis program. To address the payload constraints, the study also considered a tentative timeline that aligned with the current Artemis schedule for transporting the Bowling Habitat to the Moon. Ultimately, the Bowling Habitat mainly addressed the structural needs of an inflatable lunar habitat, meaning that major areas pertaining to the life-style aspects of the habitat must be improved. Areas include, but are not limited to, hard connection points, the monitoring of human health, and extra radiation protection for solar proton events.

Inflatable Habitat↗
NASA NTRS2000

Accretion of Moon and Earth and the emergence of life

The discrepancy between the impact records on the Earth and Moon in the time period, 4.0-3.5 Ga calls for a re-evaluation of the cause and localization of the late lunar bombardment. As one possible explanation, we propose that the time coverage in the ancient rock record is sufficiently fragmentary, so that the effects of giant, sterilizing impacts throughout the inner solar system, caused by marauding asteroids, could have escaped detection in terrestrial and Martian records. Alternatively, the lunar impact record may reflect collisions of the receding Moon with a series of small, original satellites of the Earth and their debris in the time period about 4.0-3.5 Ga. The effects on Earth of such encounters could have been comparatively small. The location of these tellurian moonlets has been estimated to have been in the region around 40 Earth radii. Calculations presented here, indicate that this is the region that the Moon would traverse at 4.0-3.5 Ga, when the heavy and declining lunar bombardment took place. The ultimate time limit for the emergence of life on Earth is determined by the effects of planetary accretion--existing models offer a variety of scenarios, ranging from low average surface temperature at slow accretion of the mantle, to complete melting of the planet followed by protracted cooling. The choice of accretion model affects the habitability of the planet by dictating the early evolution of the atmosphere and hydrosphere. Further exploration of the sedimentary record on Earth and Mars, and of the chemical composition of impact-generated ejecta on the Moon, may determine the choice between the different interpretations of the late lunar bombardment and cast additional light on the time and conditions for the emergence of life.

NASA Discipline Exobiology↗
NASA NTRS2009

Evaluating the Environmental Performance of the U.S. Next Generation Air Transportation System

The environmental impacts of several possible U.S. Next Generation Air Transportation scenarios have been quantitatively evaluated for noise, air-quality, fuel-efficiency, and CO2 impacts. Three principal findings have emerged. (1) 2025 traffic levels about 30% higher than 2006 are obtained by increasing traffic according to FAA projections while also limiting traffic at each airport using reasonable ratios of demand to capacity. NextGen operational capabilities alone enable attainment of an additional 10-15% more flights beyond that 2025 baseline level with negligible additional noise, air-quality, and fuel-efficiency impacts. (2) The addition of advanced engine and airframe technologies provides substantial additional reductions in noise and air-quality impacts, and further improves fuel efficiency. 2025 environmental goals based on projected system-wide improvement rates of about 1% per year for noise and fuel-efficiency (an air-quality goal is not yet formulated) are achieved using this new vehicle technology. (3) Overall air-transport "product", as measured by total flown distance or total payload distance, increases by about 50% relative to 2006, but total fuel consumption and CO2 production increase by only about 40% using NextGen operational capabilities. With the addition of advanced engine/airframe technologies, the increase in total fuel consumption and CO2 production can be reduced to about 30%.

Environmental impact↗
NASA NTRS2012

Can We Infer Ocean Dynamics from Altimeter Wavenumber Spectra?

The wavenumber spectra of sea surface height (SSH) and kinetic energy (KE) have been used to infer the dynamics of the ocean. When quasi-geostrophic dynamics (QG) or surface quasi-geostrophic (SQG) turbulence dominate and an inertial subrange exists, a steep SSH wavenumber spectrum is expected with k-5 for QG turbulence and a flatter k-11/3 for SQG turbulence. However, inspection of the spectral slopes in the mesoscale band of 70 to 250 km shows that the altimeter wavenumber slopes typically are much flatter than the QG or SQG predictions over most of the ocean. Comparison of the altimeter wavenumber spectra with the spectra estimated from the output of an eddy resolving global ocean circulation model (the Hybrid Coordinate Ocean Model, HYCOM, at 1/25 resolution), which is forced by high frequency winds and includes the astronomical forcing of the sun and the moon, suggests that the flatter slopes of the altimeter may arise from three possible sources, the presence of internal waves, the lack of an inertial subrange in the 70 to 250 km band and noise or submesoscales at small scales. When the wavenumber spectra of SSH and KE are estimated near the internal tide generating regions, the resulting spectra are much flatter than the expectations of QG or SQG theory. If the height and velocity variability are separated into low frequency (periods greater than 2 days) and high frequency (periods less than a day), then a different pattern emerges with a relatively flat wavenumber spectrum at high frequency and a steeper wavenumber spectrum at low frequency. The stationary internal tides can be removed from the altimeter spectrum, which steepens the spectral slopes in the energetic internal wave regions. Away from generating regions where the internal waves

Richman, James↗
NASA NTRS2005

Next Generation Launch Technology Program Lessons Learned

In November 2002, NASA revised its Integrated Space Transportation Plan (ISTP) to evolve the Space Launch Initiative (SLI) to serve as a theme for two emerging programs. The first of these, the Orbital Space Plane (OSP), was intended to provide crew-escape and crew-transfer functions for the ISS. The second, the NGLT Program, developed technologies needed for safe, routine space access for scientific exploration, commerce, and national defense. The NGLT Program was comprised of 12 projects, ranging from fundamental high-temperature materials research to full-scale engine system developments (turbine and rocket) to scramjet flight test. The Program included technology advancement activities with a broad range of objectives, ultimate applications/timeframes, and technology maturity levels. An over-arching Systems Engineering and Analysis (SE&A) approach was employed to focus technology advancements according to a common set of requirements. Investments were categorized into three segments of technology maturation: propulsion technologies, launch systems technologies, and SE&A.

Cook, Stephen↗
NASA NTRS1982

Behavior of the Si/SiO2 interface observed by Fowler-Nordheim tunneling

Thin-oxide (40-50 A) metal oxide semiconductor (MOS) structures are shown to exhibit, before large levels of electron tunnel injection, the near-ideal behavior predicted for a uniform trapezoidal barrier with thick-oxide properties. The oscillatory field dependence caused by electron-wave interference at the Si/SiO2 interface suggests an abrupt, one-monolayer barrier transition (approximately 2.5 A) consistent with earlier work. After tunnel injection of 10 to the 17th - 5 x 10 to the 18th electrons/sq cm, the barrier undergoes appreciable degradation, leading to enhanced tunneling conductance. Reproducible behavior is observed among different samples. This effect is found to be consistent with the generation of positive states in the region of the oxide near the Si/SiO2 interface (less than 20 A), where the tunneling electrons emerge into the oxide conduction band.

Maserjian, J.↗
NASA NTRS1993

Observational aspects of the low-frequency intraseasonal variability of the atmosphere in middle latitudes

An integrated description of the planetary-scale structures that emerge as organized entities on intraseasonal temporal scales in the middle latitudes is developed. Spatial scales of atmospheric motions involved in the generation of variability in the LF range are specified. An overview of the 3D structure of the seasonally averaged eddies in which the intraseasonal fluctuations are superposed is presented. The generation and maintenance mechanisms possibly responsible for the existence of the seasonal, quasi-stationary disturbances are discussed. It is shown that in the LF, low-zonal wavenumber part of the spectrum, the power displayed by standing variance exceeds that of propagating variance and vice versa for HFs and wavenumbers.

Pandolfo, Lionel↗
NASA NTRS1994

Chromospheric heating and metal deficiency in cool giants: Theoretical results versus observations

We compute acoustic shock wave-heated chromosphere models for moderately cool giant stars which differ greatly in metallicity. Subsequently, we simulate the emerging Mg II k lines assuming partial redistribution. The initial acoustic energy fluxes and the wave periods are taken from acoustic wave generation calculations based on traditional convection zone models. We find that the Mg II and Ca II core emissions are close to the observed basal flux limits which are common for giants and dwarfs. In addition, we find that the Mg II core emission is independent of the metallicity, in agreement with observations. We argue that these results should be considered as further evidence that the basal flux limits are indeed due to acoustic shock heating. The acoustic heating mechanism seems to be dominant in all nonmagnetic nonpulsating late-type stars.

Cuntz, M.↗
NASA NTRS2007

Advances in Ground Transmitters for the NASA Deep Space Network

The Deep Space Network (DSN), managed by the Jet Propulsion Laboratory for NASA, is equipped with multiple microwave transmitters ranging in average radiated power from 200 W to 400 kW. The transmitters are used for routine or emergency communication with spacecraft, for navigation, and for radio science tasks. The latest advances in transmitter engineering were implemented in a new generation of 20-kW dual-band transmitters developed for the DSN 34-m beam waveguide antennas. Innovations include additional X-band communication capability for near Earth missions, new control algorithms, automated calibration, improved and expanded computerized monitoring and diagnostics, reduced cabling, and improved maintainability. The innovations were very beneficial for the DSN 'overload' during the Mars 2003/2004 missions and will benefit other missions throughout the next decade. This paper describes the current design of the new transmitters and possible future developments.

microwaves↗
NASA NTRS2019

Towards the Development of Real-Time Normalized Burn Ratio (NBR) and Delta NBR Imagery from GOES-16/17 and S-NPP

Burned landscapes present difficult hydrologic forecasting challenges for National Weather Service Offices. Burned soils and landscapes can be conducive to the development of flash flooding and landslides from heavy precipitation events. The severity of the burn scar can be directly related to the risk for debris flows and flash flooding. Burned Area Reflectance Classification (BARC) map is generated to indicate the degree of burn severity, which is generated initially by high-resolution satellite imagery from sources such as Landsat, and later by labor-intensive efforts conducted at the burn scar by Burned Area Emergency Response (BAER) teams. The challenge for operational meteorologists is that these sources of information are not readily available in near real-time. Landsat imagery, for example, may only be available about once every eight days, and cloudy conditions can obstruct the observation of the burn scar during a single pass. BAER teams cannot conduct assessments until the wildfire has been at least 40 percent contained (up to 80 percent in some regions), and the process itself can take further days to weeks to complete depending on a number of factors. To help remedy this lapse in knowledge, NASA SPoRT has developed the generation of NBR imagery in the Advanced Weather Interactive Processing System (AWIPS) using data from the operational GOES 16 and 17 satellites and S-NPP. This presentation will discuss the development of the GOES- and SNPP-derived NBR and dNBR imagery and their initial evaluation by real-time decision makers.

Berndt, Emily↗
NASA NTRS1993

Criteria for evaluation of grid generation systems

Many CFD grid generation systems are in use nationally, but few comparative studies have been performed to quantify their relative merits. A study was undertaken to systematically evaluate and select the best CFD grid generation codes available. Detailed evaluation criteria were established as the basis for the evaluation conducted. Descriptions of thirty-four separate criteria, grouped into eight general categories are provided. Benchmark test cases, developed to test basic features of selected codes, are described in detail. Scoring guidelines were generated to establish standards for measuring code capabilities, ensuring uniformity of ratings, and minimizing personal bias among the three code evaluators. Ten candidate codes were identified from government, industry, universities, and commercial software companies. A three phase evaluation was conducted. In Phase 1, ten codes identified were screened through conversations with code authors and other industry experts. Seven codes were carried forward into a Phase 2 evaluation in which all codes were scored according to the predefined criteria. Two codes emerged as being significantly better than the others: RAGGS and GRIDGEN. Finally, these two codes were carried forward into a Phase 3 evaluation in which complex 3-D multizone grids were generated to verify capability.

Ascoli, Edward P.↗
NASA NTRS2012

Applying Biomimetic Algorithms for Extra-Terrestrial Habitat Generation

The objective is to simulate and optimize distributed cooperation among a network of robots tasked with cooperative excavation on an extra-terrestrial surface. Additionally to examine the concept of directed Emergence among a group of limited artificially intelligent agents. Emergence is the concept of achieving complex results from very simple rules or interactions. For example, in a termite mound each individual termite does not carry a blueprint of how to make their home in a global sense, but their interactions based strictly on local desires create a complex superstructure. Leveraging this Emergence concept applied to a simulation of cooperative agents (robots) will allow an examination of the success of non-directed group strategy achieving specific results. Specifically the simulation will be a testbed to evaluate population based robotic exploration and cooperative strategies while leveraging the evolutionary teamwork approach in the face of uncertainty about the environment and partial loss of sensors. Checking against a cost function and 'social' constraints will optimize cooperation when excavating a simulated tunnel. Agents will act locally with non-local results. The rules by which the simulated robots interact will be optimized to the simplest possible for the desired result, leveraging Emergence. Sensor malfunction and line of sight issues will be incorporated into the simulation. This approach falls under Swarm Robotics, a subset of robot control concerned with finding ways to control large groups of robots. Swarm Robotics often contains biologically inspired approaches, research comes from social insect observation but also data from among groups of herding, schooling, and flocking animals. Biomimetic algorithms applied to manned space exploration is the method under consideration for further study.

Birge, Brian↗
NASA NTRS1986

Experiments on annular liquid jet instability and on the formation of liquid shells

An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Experiments are described in which such a flow is generated by an annular nozzle operated at fairly specific conditions. It is shown that periodic, axisymmetric oscillations arise spontaneously within the cylindrical sheet emerging from the nozzle and grow with such rapidity along the axial dimension that a sealing-off and encapsulation of the core gas occurs within a few jet diameters. This is closely followed by a pinchoff of the liquid between adjacent bubbles. The liquid shells set free thereby assume spherically symmetric form under capillary forces, and each contains a precisely uniform measure of gas and of liquid on account of the extremely high frequency-stability of the process. Description is given of the fluid dynamic processes by which the shells are formed, and mention is made of exploiting the instability for the production of rigid shells for technological applications.

Kendall, J. M.↗