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All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

The Use of Thermal Remote Sensing to Study Thermodynamics of Ecosystem Development

Thermal remote sensing can provide environmental measuring tools with capabilities for measuring ecosystem development and integrity. Recent advances in applying principles of nonequilibrium thermodynamics to ecology provide fundamental insights into energy partitioning in ecosystems. Ecosystems are nonequilibrium systems, open to material and energy flows, which grow and develop structures and processes to increase energy degradation. More developed terrestrial ecosystems will be more effective at dissipating the solar gradient (degrading its energy content). This can be measured by the effective surface temperature of the ecosystem on a landscape scale. A series of airborne thermal infrared multispectral scanner data were collected from several forested ecosystems ranging from a western US douglas-fir forest to a tropical rain forest in Costa Rica. These data were used to develop measures of ecosystem development and integrity based on surface temperature.

Luvall, Jeffrey C.↗
NASA NTRS2001

Thermal Remote Sensing and the Thermodynamics of Ecosystems Development

Thermal remote sensing can provide environmental measuring tools with capabilities for measuring ecosystem development and integrity. Recent advances in applying principles of nonequilibrium thermodynamics to ecology provide fundamental insights into energy partitioning in ecosystems. Ecosystems are nonequilibrium systems, open to material and energy flows, which grow and develop structures and processes to increase energy degradation. More developed terrestrial ecosystems will be more effective at dissipating the solar gradient (degrading its energy content). This can be measured by the effective surface temperature of the ecosystem on a landscape scale. A series of airborne thermal infrared multispectral scanner data were collected from several forested ecosystems ranging from a western US douglas-fir forest to a tropical rain forest in Costa Rica. Also measured were agriculture systems. These data were used to develop measures of ecosystem development and integrity based on surface temperature.

Luvall, Jeffrey C.↗
NASA NTRS2002

Minimum Arc Threshold Voltage Experiments on Extravehicular Mobility Unit Samples

The International Space Station (ISS) is now under construction in Low Earth Orbit (LEO). The process of building the ISS requires that astronauts carry out many Extravehicular Activities. To protect the astronauts form the hazardous space environment, they are required to wear a suit known as the Extravehicular Mobility Unit (EMU). For most Extra-Vehicular Activities (EVAs) the EMU is tethered to ISS via a steel safety tether. During the course of an EVA it is common for the safety tether to contact exposed metal on both the ISS and the EMU. In this case, the single point ground of the EMU would be at the same potential as the ISS with respect to the LEO Plasma. In the event that the metal structure of the ISS begins to charge negative of the plasma potential as a result of electron collection by the ISS photovoltaic arrays, then the EMU would also be driven to a negative potential. Anodized aluminum components on the EMU would then begin to develop a charge across their amortization layer as ions from the plasma are collected. In the case where large negative potentials are applied to the EMU, dielectric breakdown may occur as a large voltage difference is developed across the thin amortization layer (oxide). The resulting arc plasma may in turn couple to the charge accumulated on the nearby ISS anodized debris shields and thereby generate a large current flow through the metal EMU structure. Current flow through the EMU could result in an electrocution hazard for the Crew Member inside the EMU - and therefore represents an important safety concern. To address this concern, a series of experiments have been undertaken. In each experiment specially prepared anodized aluminum samples were placed in a LEO representative plasma and charged until dielectric breakdown occurred in the form of an arc. This process was repeated a number of times for three sets of samples. During each test the arc voltage and current were monitored. A statistical treatment of the arc voltage threshold will be presented. In addition, safe operating voltages for the EMU are suggested.

Schneider, Todd↗
NASA NTRS2011

International Space Station Urine Monitoring System Functional Integration and Science Testing

Exposure to microgravity during human spaceflight needs to be better understood as the human exploration of space requires longer duration missions. It is known that long term exposure to microgravity causes bone loss. Measuring the calcium and other metabolic byproducts in a crew member s urine can evaluate the effectiveness of bone loss countermeasures. The International Space Station (ISS) Urine Monitoring System (UMS) is an automated urine collection device designed to collect urine, separate the urine and air, measure the void volume, and allow for syringe sampling. Accurate measuring and minimal cross-contamination is essential to determine bone loss and the effectiveness of countermeasures. The ISS UMS provides minimal cross-contamination (<0.7 mL urine) and has volume accuracy of 2% between 100 to 1000 mL urine voids. Designed to provide a non-invasive means to collect urine samples from crew members, the ISS UMS operates in-line with the Node 3 Waste and Hygiene Compartment (WHC). The ISS UMS has undergone modifications required to interface with the WHC, including material changes, science algorithm improvements, and software platform revisions. Integrated functional testing was performed to determine the pressure drop, air flow rate, and the maximum amount of fluid capable of being discharged from the UMS to the WHC. This paper will detail the results of the science and the functional integration tests.

Rodriquez, Branelle R.↗
NASA NTRS2009

Proceedings of Minnowbrook Workshops I to VI

This DVD collection includes the complete proceedings of Minnowbrook Workshops I through VI. Titles include Minnowbrook I - 1993 Workshop on End-Stage Boundary Layer Transition (NASA/CP-2007-214667, CASI ID 20070038942), Minnowbrook II - 1997 Workshop on Boundary Layer Transition in Turbomachines (NASA/CP-1998-206958, CASI ID 19980206205), Minnowbrook III - 2000 Workshop on Boundary Layer Transition and Unsteady Aspects of Turbomachinery Flow (NASA/CP-2001-210888, CASI ID 20020067662), Minnowbrook IV - 2003 Workshop on Transition and Unsteady Aspects of Turbomachinery Flows (NASA TM-2004-212913, CASI ID 20040121174), Minnowbrook V - 2006 Workshop on Unsteady Flows in Turbomachinery (NASA/CP-2006-214484, CASI ID 20070024781), and Minnowbrook VI - 2009 Workshop on Flow Physics and Control for Internal and External Aerodynamics (NASA/CP-2010-216112, CASI ID 20100018557).

John E. Lagraff↗
NASA NTRS2014

A Multifaceted Approach to Modernizing NASA's Advanced Multi-Mission Operations System (AMMOS) System Architecture

The Advanced Multi-Mission Operations Systems (AMMOS) is NASA's premier space mission operations product line offering for use in deep-space robotic and astrophysics missions. The general approach to AMMOS modernization over the course of its 29-year history exemplifies a continual, evolutionary approach with periods of sponsor investment peaks and valleys in between. Today, the Multimission Ground Systems and Services (MGSS) office-the program office that manages the AMMOS for NASA-actively pursues modernization initiatives and continues to evolve the AMMOS by incorporating enhanced capabilities and newer technologies into its end-user tool and service offerings. Despite the myriad of modernization investments that have been made over the evolutionary course of the AMMOS, pain points remain. These pain points, based on interviews with numerous flight project mission operations personnel, can be classified principally into two major categories: 1) information-related issues, and 2) process-related issues. By information-related issues, we mean pain points associated with the management and flow of MOS data across the various system interfaces. By process-related issues, we mean pain points associated with the MOS activities performed by mission operators (i.e., humans) and supporting software infrastructure used in support of those activities. In this paper, three foundational concepts-Timeline, Closed Loop Control, and Separation of Concerns-collectively form the basis for expressing a set of core architectural tenets that provides a multifaceted approach to AMMOS system architecture modernization intended to address the information- and process-related issues. Each of these architectural tenets will be further explored in this paper. Ultimately, we envision the application of these core tenets resulting in a unified vision of a future-state architecture for the AMMOS-one that is intended to result in a highly adaptable, highly efficient, and highly cost-effective set of multimission MOS products and services.

Estefan, Jeff A.↗
NASA NTRS1983

An experimental investigation of the low Reynolds number performance of the Lissaman 7769 airfoil

A Lissaman 7769 airfoil, used on the Gossamer Condor and Gossamer Albatross human-powered aircraft, was tested in a low turbulence subsonic wind tunnel. Lift and drag data were collected at chord Reynolds numbers of 100,000, 150,000, 200,000, 250,000, and 300,000; at angles of attack from -10 to +20 deg by using an external strain gage force balance. Lift curves, drag curves, and drag polars were generated from both uncorrected data and data corrected for wind tunnel blockage effects. A flow visualization study was performed to correlate with the force data. The results of the investigation have shown that the airfoil exhibits a significant degradation in performance for chord Reynolds numbers below 150,000.

Conigliaro, P. E.↗
NASA NTRS1986

The optical structure of the Crab Nebula's 'jet'

A deep, high-resolution forbidden O III image of the Crab Nebula's northern 'jet' is presented which reveals considerably finer details than visible on previous photographs. The jet's small-scale structure appears composed of numerous emission-line filaments and knots which collectively exhibit a strong alignment having well-defined east-west boundaries. Comparison with an earlier published image suggests a proper motion northward for one of the jet's emission knots of 0.22 + or - 0.05 arcsec/yr. The jet's optical morphology is discussed and its properties compared to predictions of several proposed models. The 'shadowed flow' model suggested by Morrison and Roberts (1985) appears to explain best the jet's known properties.

Fesen, R. A.↗
NASA NTRS1986

A two-dimensional model of the ionosphere of Venus - Thermal structure

A spectral model is defined for the electron and ion temperature profiles of the Venus ionosphere. The model is developed using data collected with the retarding potential analyzer on the Pioneer Venus Orbiter, and account is taken of horizontal bulk heat transport and a heat flux saturation effect. Coupled ion and energy equations and thermal flux equations are defined. A finite difference algorithm is applied to solve the equations, assuming an ionopause at 740 km altitude. Horizontal plasma flow velocities of 2.5-5.6 km/sec are found necessary in order to account for a dip in the ion temperature around the terminator and a sharp rise at about 140 deg, i.e., far past the solar zenith angle. An external heat source of 0.0001-0.0002 ergs/sq cm per sec, uniformly distributed around Venus, is required to maintain observed dayside and nightside ion temperatures. The heat source may be the solar wind, which would be sufficient without shocks.

Singhal, R. P.↗
NASA NTRS1990

Making Topographical Maps From SAR and Flood-Gauge Data

Collection of computer programs processes image data obtained by synthetic-aperture radar (SAR) along with measurements of water levels taken at selected points on ground to generate three-dimensional maps of surveyed terrain. Information in maps presented in variety of useful ways suited to study of such phenomena as flooding, damage caused by floods, flow of nutrients from forests to river and marine ecosystems, and effects of subsidence of ground or of rising sea levels.

Imhoff, Marc Lee↗
NASA NTRS1990

An imaging system for PLIF/Mie measurements for a combusting flow

The equipment required to establish an imaging system can be divided into four parts: (1) the light source and beam shaping optics; (2) camera and recording; (3) image acquisition and processing; and (4) computer and output systems. A pulsed, Nd:YAG-pummped, frequency-doubled dye laser which can freeze motion in the flowfield is used for an illumination source. A set of lenses is used to form the laser beam into a sheet. The induced fluorescence is collected by an UV-enhanced lens and passes through an UV-enhanced microchannel plate intensifier which is optically coupled to a gated solid state CCD camera. The output of the camera is simultaneously displayed on a monitor and recorded on either a laser videodisc set of a Super VHS VCR. This videodisc set is controlled by a minicomputer via a connection to the RS-232C interface terminals. The imaging system is connected to the host computer by a bus repeater and can be multiplexed between four video input sources. Sample images from a planar shear layer experiment are presented to show the processing capability of the imaging system with the host computer.

Wey, C. C.↗
NASA NTRS1996

Challenges and Accomplishments of Viscous Incompressible Flow Computations in Aerospace and Beyond

Recent progress in incompressible Navier-Stokes solution methods will be presented. Discussions are focused on the methods designed for complex geometry applications in three dimensions, and thus are limited to primitive variable formulation. Both steady- and unsteady-solution algorithms and their salient features are discussed. A summary of our recent progress in flow solver development is given followed by numerical studies of a few example problems of our current interest. Solvers discussed here are based on structured-grid approach using finite-difference or finite-volume frame work. This short course will be delivered in three one-our lectures. The material in the course are collected from the work performed by the Incompressible Navier-Stokes group at NASA Ames Research Center over the past several years, and can be found in our publications widely disseminated in the US and abroad. This short course is sponsored by AGARD Consultant and Exchange Program under Support Project P-110.

Kwak, Dochan↗
NASA NTRS1993

The role of psychoneuroendocrine factors on spaceflight-induced immunological alterations

This paper summarizes previous in-flight infections and novel conditions of spaceflight that may suppress immune function. Granulocytosis, monocytosis, and lymphopenia are routinely observed following short duration orbital flights. Subtle changes within the monocyte and T cell populations can also be noted by flow cytometric analysis. The similarity between the immunological changes observed after spaceflight and other diverse environmental stressors suggest that most of these alterations may be neuroendocrine-mediated. Available data support the hypothesis that spaceflight and other environmental stressors modulate normal immune regulation via stress hormones, other than exclusively glucocorticoids. It will be essential to simultaneously collect in-flight endocrine, immunologic, and infectious illness data to determine the clinical significance of these results. Additional research that delineates the neuroendocrine mechanisms of stress-induced changes in normal immune regulation will allow clinicians in the future to initiate prophylactic immunomodulator therapy to restore immune competence altered by the stress of long-duration spaceflight and therefore reduce morbidity from infectious illness, autoimmune disease, or malignancy.

Salyut Project↗
NASA NTRS2013

Background Oriented Schlieren Implementation in a Jet-Surface Interaction Test

Many current and future aircraft designs rely on the wing or other aircraft surfaces to shield the engine noise from observers on the ground. However the available data regarding how a planar surface interacts with a jet to shield and/or enhance the jet noise are currently limited. Therefore, the Jet-Surface Interaction Tests supported by NASA's Fundamental Aeronautics Program's Fixed Wing Project were undertaken to supply experimental data covering a wide range of surface geometries and positions interacting with high-speed jet flows in order to support the development of noise prediction methods. Phase 1 of the Test was conducted in the Aero-Acoustic Propulsion Laboratory at NASA Glenn Research Center and consisted of validating noise prediction schemes for a round nozzle interacting with a planar surface. Phased array data and far-field acoustic data were collected for both the shielded and reflected sides of the surface. Phase 1 results showed that the broadband shock noise was greatly reduced by the surface when the jet was operated at the over-expanded condition, however, it was unclear whether this reduction was due a change in the shock cell structure by the surface. In the present study, Background Oriented Schlieren is implemented in Phase 2 of the Jet-Surface Interaction Tests to investigate whether the planar surface interacts with the high-speed jet ow to change the shock cell structure. Background Oriented Schlieren data are acquired for under-expanded, ideally-expanded, and over-expanded ow regimes for multiple axial and radial positions of the surface at three different plate lengths. These data are analyzed with far-field noise measurements to relate the shock cell structure to the broadband shock noise produced by a jet near a surface.

Clem, Michelle M.↗
NASA NTRS2015

Time-Accurate Unsteady Pressure Loads Simulated for the Space Launch System at Wind Tunnel Conditions

A transonic flow field about a Space Launch System (SLS) configuration was simulated with the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics (CFD) code at wind tunnel conditions. Unsteady, time-accurate computations were performed using second-order Delayed Detached Eddy Simulation (DDES) for up to 1.5 physical seconds. The surface pressure time history was collected at 619 locations, 169 of which matched locations on a 2.5 percent wind tunnel model that was tested in the 11 ft. x 11 ft. test section of the NASA Ames Research Center's Unitary Plan Wind Tunnel. Comparisons between computation and experiment showed that the peak surface pressure RMS level occurs behind the forward attach hardware, and good agreement for frequency and power was obtained in this region. Computational domain, grid resolution, and time step sensitivity studies were performed. These included an investigation of pseudo-time sub-iteration convergence. Using these sensitivity studies and experimental data comparisons, a set of best practices to date have been established for FUN3D simulations for SLS launch vehicle analysis. To the author's knowledge, this is the first time DDES has been used in a systematic approach and establish simulation time needed, to analyze unsteady pressure loads on a space launch vehicle such as the NASA SLS.

Alter, Stephen J.↗
NASA NTRS2024

Going With the Flow: Sedimentary Evolution of the Jezero Western Fan, Mars

Sedimentary fans developed at the mouths of Martian valleys have been interpreted as the deposits of sustained surface water flow on early Mars building either fluvial fan systems or deltas into standing bodies of water. Whilst much insight has been gleaned from orbital observations, it is only possible to constrain the character, relative timing and persistence of ancient aqueous activity on Mars through detailed on-the-ground interrogation of sedimentary successions built during fan growth. A prominent sedimentary fan deposit at the western margin of Jezero crater – the Western fan – has been interpreted from orbital data/observations to be a river delta that prograded into an ancient lake basin during the Late Noachian-Early Hesperian epochs on Mars (~3.6-3.8 Ga). The Western fan deposit forms a point-sourced depositional system developed at the mouth of Neretva Vallis, a valley system that is incised across the crater rim and has an extensive extra-crater catchment draining over diverse ancient geological units in Nili Planum. The mechanism of crater rim breaching remains unconstrained. Between 2022 and 2023, the Mars 2020 Perseverance rover explored the Western fan, with the objective of characterizing its paleoenvironmental context and collecting a diverse suite of sedimentary rock samples for return to Earth via the Mars Sample Return mission. Perseverance has now completed her traverse across the Western fan having commenced in the distal downstream sectors exposed at the erosional front of the fan and then crossing across its upper exposed surface toward the fan apex region near the mouth of Neretva Vallis. This transect provides a unique window into a Martian sediment routing system at a time when climate conditions permitted the flow of surface water. In this contribution, we review the overall sedimentary architecture of the fan and develop a model for its evolution based on detailed mapping of lithofacies changes across the fan. A first-order synoptic overview is presented.

Mars 2020↗
NASA NTRS2001

Ecophysiological Changes in Microbial Mats Incubated in a Greenhouse Collaboratory

Microbial mats are modern examples of the earliest microbial communities known. Among the best studied are microbial mats growing in hypersaline ponds managed for the production of salt by Exportadora de Sal, S.A. de C.V., Guerrero Negro, Baja California Sur, Mexico. In May, 2001, we collected mats from Ponds 4 and 5 in this system and returned them to Ames Research Center, where they have been maintained for a period of over nine months. We report here on both the ecophysiological changes occurring in the mats over that period of time as well as the facility in which they were incubated. Mats (approximately 1 sq. meter total area) were incubated in a greenhouse facility modified to provide the mats with natural levels of visible and ultraviolet radiation as well as constantly flowing, temperature-controlled water. Two replicated treatments were maintained, a 'high salinity' treatment (about 120 ppt) and a 'low salinity' treatment (about 90 ppt). Rates of net biological activity (e.g., photosynthesis, respiration, trace gas production) in the mats were relatively constant over the several months, and were similar to rates of activity measured in the field. However, over the course of the incubation, mats in both treatments changed in physical appearance. The most obvious change was that mats in the higher salinity treatments developed a higher proportion of carotenoid pigments (relative to chlorophyll), resulting in a noticeably orange color in the high salinity mats. This trend is also seen in the natural salinity gradient present at the field site. Changes in the community composition of the mats, as assayed by denaturing gradient gel electrophoresis (DGGE), as well as biomarker compounds produced in the mats were also monitored. The degree to which the mats kept in the greenhouse changed from the originally collected mats, as well as differences between high and low salinity mats will be discussed. Additional information is contained in the original extended abstract.

Bebout, Brad↗
NASA NTRS2002

Setting up a Rayleigh Scattering Based Flow Measuring System in a Large Nozzle Testing Facility

A molecular Rayleigh scattering based air density measurement system has been built in a large nozzle testing facility at NASA Glenn Research Center. The technique depends on the light scattering by gas molecules present in air; no artificial seeding is required. Light from a single mode, continuous wave laser was transmitted to the nozzle facility by optical fiber, and light scattered by gas molecules, at various points along the laser beam, is collected and measured by photon-counting electronics. By placing the laser beam and collection optics on synchronized traversing units, the point measurement technique is made effective for surveying density variation over a cross-section of the nozzle plume. Various difficulties associated with dust particles, stray light, high noise level and vibration are discussed. Finally, a limited amount of data from an underexpanded jet are presented and compared with expected variations to validate the technique.

Panda, Jayanta↗