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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Prefreshman and Cooperative Education Program

Of the 93 students enrolled in the PREFACE program over its four-year history, 70 are still in engineering school. Tables show profiles of student placement and participation from 1973 to 1977 (first semester completed). During the 1977 summer, 10 students were placed at NASA Goddard, 8 at DOE-Brookhaven, and 2 at American Can. Eleven students with less high school math preparation remained on campus for formal precalculus classes. Majors of the students in the program include civil, chemical, electrical, and mechanical engineering. Student satisfaction with their training experiences is summarized.

Source record↗
NASA NTRS1991

The helium abundance of Neptune from Voyager measurements

The He abundance in the Neptunian atmosphere is estimated using results from Voyager radio occultation and IR spectrometer measurements. It is found that the shape of the measured spectrum cannot be matched by spectra calculated from atmospheric models that include only gaseous opacity, indicating that there might exist an additional opacity source associated with clouds or hazes. The data obtained could be fit with either of the two general classes of horizontally homogeneous cloud opacity models: (1) a model consisting of a tropospheric cloud with an optical thickness at 200/cm between 1 and 8; and (2) a stratospheric cloud with an optical thickness between 0.2 and 0.8.

Conrath, B. J.↗
NASA NTRS1992

Design tradeoffs on engine-integrated hypersonic vehicles

Two classes of airbreathing hypersonic vehicle concepts, one for primarily cruise missions and the other for accelerator type missions, are presented. Both are designed with waverider airframes and hydrogen-fueled scramjet engine modules. Cruise configurations are optimized for the product of I(sp) and L/D while matching lift to weight and thrust to drag at some equivalence ratio. Accelerator configurations are optimized for effective specific impulse while matching lift to weight at an equivalence ratio of one. The method and computer code developed to optimize the configurations are discussed. The features and design tradeoffs for each class of vehicles are described. Recently available weight estimates for all-body waveriders have had a significant impact on the integrated configurations. Mach 8 vehicles at 40 km altitude optimized with the cruise objective function have L/Ds of 2.55 to 2.92 and I(sp)s of 2850 to 2940 sec. A Mach 14 vehicle at 40-km altitude optimized with the accelerator objective function has an I(sp) sub eff of 189 sec, and a Mach 10 vehicle an I(sp) sub eff of 880 sec.

O'Neill, Mary Kae L.↗
NASA NTRS2014

Stability Analysis of ISS Medications

It is known that medications degrade over time, and that extreme storage conditions will hasten their degradation. The temperature and humidity conditions of the ISS have been shown to be within the ideal ranges for medication storage, but the effects of other environmental factors, like elevated exposure to radiation, have not yet been evaluated. Current operational procedures ensure that ISS medications are re-stocked before expiration, but this may not be possible on long duration exploration missions. For this reason, medications that have experienced long duration storage on the ISS were returned to JSC for analysis to determine any unusual effects of aging in the low- Earth orbit environment. METHODS Medications were obtained by the JSC Pharmacy from commercial distributors and were re-packaged by JSC pharmacists to conserve up mass and volume. All medication doses were part of the ISS crew medical kit and were transported to the International Space Station (ISS) via NASA's Shuttle Transportation System (Space Shuttle). After 568 days of storage, the medications were removed from the supply chain and returned to Earth on a Dragon (SpaceX) capsule. Upon return to Earth, medications were transferred to temperature and humidity controlled environmental chambers until analysis. Nine medications were chosen on the basis of their availability for study. The medications included several of the most heavily used by US crewmembers: 2 sleep aids, 2 antihistamines/decongestants, 3 pain relievers, an antidiarrheal and an alertness medication. Each medication was available at a single time point; analysis of the same medication at multiple time points was not possible. Because the samples examined in this study were obtained opportunistically from medical supplies, there were no control samples available (i.e. samples aged for a similar period of time on the ground); a significant limitation of this study. Medications were analyzed using the HPLC/MS methods described in the United States Pharmacopeia (USP) to measure the amount of intact active ingredient, identify degradation products and measure their amounts. Some analyses were conducted by an independent analytical laboratory, but certain (Schedule) medications could not be shipped to their facility and were analyzed at JSC. RESULTS Nine medications were analyzed with respect to active pharmaceutical ingredient (API) and degradant amounts. Results were compared to the USP requirements for API and degradants/impurities content for every FDA-approved medication. One medication met USP requirements at 5 months after its expiration date. Four of the nine (44% of those tested) medications tested met USP requirements up to 8 months post-expiration. Another 3 medications (33% of those tested) met USP guidelines 2-3 months before expiration. One medication, a compound classed by the FDA as a dietary supplement and sometimes used as a sleep aid, failed to meet USP requirements at 11 months post-expiration. CONCLUSION Analysis of each medication at a single time point provides limited information on the stability of a medication stored in particular conditions; it is not possible to predict how long a medication may be safe and effective from these data. Notwithstanding, five of the nine medications tested (56%) met USP requirements for API and degradants/impurities at least 5 months past expiration dates. The single compound that failed to meet USP requirements is not regulated as strictly as prescription medications are during manufacture; it is unknown if this medication would have met the requirements prior to flight. Notably, it was the furthest beyond its expiration date. Only more comprehensive analysis of flight-aged samples compared to appropriate ground controls will permit determination of spaceflight effects on medication stability.

Wotring, V. E.↗
NASA NTRS2018

NASA's Space Launch System: Unprecedented Payload Capabilities

As NASA turns 60 and plans to transition the International Space Station (ISS) and other low-Earth orbit (LEO) activities to commercial enterprises, the Agency's human exploration program turns its focus to deep space. With missions planned to send astronauts back to the Moon and to construct a lunar orbiting Gateway for surface access as well as science experiments and technology demonstrations, NASA requires a vehicle with capabilities for launching more mass and volume than is currently commercially available. To that end, NASA and its private sector partners are building the Space Launch System (SLS) super heavy-lift launch vehicle, which will send the new Orion crew capsule, eventually with a complement of four astronauts, to cislunar space for the first time since the Apollo Program in the 1960s and 1970s. NASA Kennedy Space Center's (KSC's) Exploration Ground Systems (EGS) Program has upgraded and refurbished ground and launch facilities to process, assemble and launch NASA's new deep space exploration system, which is managed by the Exploration Systems Development (ESD) organization in the Human Exploration and Operations Mission Directorate (HEOMD). Offering an unmatched combination of power, payload capacity and departure energy, the evolvable SLS features the world's most proven propulsion system: solid rocket boosters and RS-25 main engines with a modified Delta Cryogenic Second Stage (DCSS) cryogenic upper stage. The initial SLS configuration, Block 1, will deliver at least 26 metric tons (t) to trans-lunar injection (TLI). The second variant, Block 1B, will deliver at least 34 t to TLI in its crew configuration and at least 40 t to TLI in its cargo configuration. The Block 1 cargo vehicle will fly with an industry-standard 5 m fairing while the Block 1B cargo configuration will accommodate 8 m-diameter fairings in varying lengths. The Block 2 vehicle will incorporate upgraded boosters and possibly larger fairings for launching Mars-class payloads to deep space. Although designed to enable human exploration of deep space, the vehicle also provides game-changing benefits for large science payloads and even harnesses excess capacity to provide small satellites with access to deep space. Three flights of the Block 1 vehicle are now planned; the first vehicle, being built for a test flight known as Exploration Mission-1 (EM-1), is nearing completion at NASA and contractor sites across the United States. In fact, hardware for the second mission has also been built. This paper will provide an overview of the SLS vehicle, with a focus on its payload accommodations and the missions enabled by the unprecedented payload volume and departure energy of SLS. This paper also describes the status of the manufacturing and integration for first flight and beyond.

Exploration Mission-1↗
NASA NTRS1973

Automatic photointerpretation for plant species and stress identification (ERTS-A1)

The author has identified the following significant results. Automatic stratification of forested land from ERTS-1 data provides a valuable tool for resource management. The results are useful for wood product yield estimates, recreation and wildlife management, forest inventory, and forest condition monitoring. Automatic procedures based on both multispectral and spatial features are evaluated. With five classes, training and testing on the same samples, classification accuracy of 74 percent was achieved using the MSS multispectral features. When adding texture computed from 8 x 8 arrays, classification accuracy of 90 percent was obtained.

Swanlund, G. D.↗
NASA NTRS2003

The Explorer of Diffuse Galactic Emission (EDGE): Determining the Large-Scale Structure Evolution in the Universe

Measurements of the large-scale anisotropy of the Cosmic Infared Background (CIB) can be used to determine the characteristics of the distribution of galaxies at the largest spatial scales. With this information important tests of galaxy evolution models and primordial structure growth are possible. In this paper, we describe the scientific goals, instrumentation, and operation of EDGE, a mission using an Antarctic Long Duration Balloon (LDB) platform. EDGE will osbserve the anisotropy in the CIB in 8 spectral bands from 270 GHz-1.5 THz with 6 arcminute angular resolution over a region -400 square degrees. EDGE uses a one-meter class off-axis telescope and an array of Frequency Selective Bololeters (FSB) to provide the compact and efficient multi-colar, high sensitivity radiometer required to achieve its scientific objectives.

Silverberg, R. F.↗
NASA NTRS2019

PDC19 Impact Exercise: Probabilistic Asteroid Impact Risk Assessment

Probabilistic Asteroid Impact Risk (PAIR) - PDC (Planetary Defense Conference) 2019 Hypothetical Exercise, NASA Ames, Asteroid Threat Assessment Project (ATAP) - Characterization Summary and Updates: Assessment date: 19 April 2027; Impact date: 29 April 2027 (10 days); Earth impact probability: 100 percent, New York Area; Diameter (meters): 60 plus or minus 10 (1 minus sigma), range 26–93; Energy: mean 11 megatons, range 650 kilotons to 46 megatons; Type: S class, remaining chunk of disrupted contact binary. Risk Summary: Affected population: mean 2.4 million, range zero to 10.2 million; Likely airburst at approximately16 kilometers altitude (8 to 29 kilometers); Blast overpressure is primary hazard; Damage out to approximately 70 kilometers if larger, lower burst; Little-to-no damage if burst is small and high.

Wheeler, Lorien↗
NASA NTRS2020

Mark Twain National Forest Ecological Forecasting - Utilizing NASA Earth Observations to Classify Ground Cover Types in the Mark Twain National Forest

The Mark Twain National Forest (MTNF) encompasses 1.5 million acres of public land in the Ozarks region of southeastern Missouri. The industrial boom between the 1880s and 1920s had devastating effects on the shortleaf pine (Pinus echinata),Missouri’s only native pine species. The combination of fire suppression on this fire-dependent species and timber harvest of mature pine stands inhibited the development of pine seedlings and promoted the establishment of hardwood stands. Partners at the US Forest Service’s MTNF are currently involved in restoration efforts in two ranger districts, which includes removing invasive eastern red cedar (Juniperus virginiana) and prescribed burning. To expand spatial coverage for the MTNF beyond in situ observation sites, the NASA DEVELOP team analyzed land cover change from 1986 through 2019 and forecasted changes based on a ‘business-as-usual' scenario out to 2040. The team incorporated remotely sensed data from Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) into the random trees supervised classification tool in ArcGIS Pro. This tool spectrally separated pixels into five distinct land cover classes and produced classifications for 1986 and 2019, with kappa statistics of 0.87 and 0.81, respectively. Overall, there was a net decrease in conifer and meadow land cover between 1986 and 2019 along with a net increase in water, developed, and deciduous land cover. The team used TerrSet’s Land Change Modeler to forecast land cover through 2040. Results showed an increase in coniferous land cover and a decrease in deciduous cover, indicating a high probability that current restoration efforts will produce the intended effect.

Kaitlyn Bretz↗
NASA NTRS2020

Mark Twain National Forest Ecological Forecasting: Utilizing NASA Earth Observations to Classify Ground Cover Types in the Mark Twain National Forest

The Mark Twain National Forest (MTNF) encompasses 1.5 million acres of public land in the Ozarks region of southeastern Missouri. The industrial boom between the 1880s and 1920s had devastating effects on the shortleaf pine (Pinus echinata),Missouri’s only native pine species. The combination of fire suppression on this fire-dependent species and timber harvest of mature pine stands inhibited the development of pine seedlings and promoted the establishment of hardwood stands. Partners at the US Forest Service’s MTNF are currently involved in restoration efforts in two ranger districts, which includes removing invasive eastern red cedar (Juniperus virginiana) and prescribed burning. To expand spatial coverage for the MTNF beyond in situ observation sites, the NASA DEVELOP team analyzed land cover change from 1986 through 2019 and forecasted changes based on a ‘business-as-usual' scenario out to 2040. The team incorporated remotely sensed data from Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) into the random trees supervised classification tool in ArcGIS Pro. This tool spectrally separated pixels into five distinct land cover classes and produced classifications for 1986 and 2019, with kappa statistics of 0.87 and 0.81, respectively. Overall, there was a net decrease in conifer and meadow land cover between 1986 and 2019 along with a net increase in water, developed, and deciduous land cover. The team used TerrSet’s Land Change Modeler to forecast land cover through 2040. Results showed an increase in coniferous land cover and a decrease in deciduous cover, indicating a high probability that current restoration efforts will produce the intended effect.

DEVELOP Tech Paper↗
NASA NTRS2003

Titan Explorer mission trades from the perspective of aerocapture

A detailed Titan aerocapture systems analysis and spacecraft design study was performed as part of NASA's In-Space Propulsion Program. The primary objective was to engineer a point design based on blunt body aeroshell technology and quantitatively assess feasibility and performance. This paper reviews the launch vehicle, propulsion, and trajectory options to reach Titan in the 2010-2015 time frame using aerocapture and all-propulsive vehicles. It establishes the range of entry conditions that would be consistent with delivering a 360 kg entry vehicle plus a 580 kg orbiter to Titan. Results show that inertial entry velocities in the range of 5.3 to 6.6 kmls are to be expected for chemical and solar electric propulsion options with Venus and/or Earth gravity assists. Trip times range from approximately 6 years for aerocapture orbiters to 8-11 years for all-propulsive vehicles. In addition to trip time reduction, the use of aerocapture enables the mission with a Delta 4450 class launch vehicle as opposed to an all-propulsive orbit insertion approach, which requires a Delta IV heavy or Titan IV class launch vehicle.

Bailey, Robert W.↗
NASA NTRS2013

Absorption Efficiencies of Forsterite. I: DDA Explorations in Grain Shape and Size

We compute the absorption efficiency (Q(sub abs)) of forsterite using the discrete dipole approximation (DDA) in order to identify and describe what characteristics of crystal grain shape and size are important to the shape, peak location, and relative strength of spectral features in the 8 - 40 micron wavelength range. Using the DDSCAT code, we compute Q(sub abs) for non-spherical polyhedral grain shapes with a(sub eff) = 0.1 micron. The shape characteristics identified are: 1) elongation/reduction along one of three crystallographic axes; 2) asymmetry, such that all three crystallographic axes are of different lengths; and 3) the presence of crystalline faces that are not parallel to a specific crystallographic axis, e.g., non-rectangular prisms and (di)pyramids. Elongation/reduction dominates the locations and shapes of spectral features near 10, 11, 16, 23.5, 27, and 33.5 micron, while asymmetry and tips are secondary shape effects. Increasing grain sizes (0.1 - 1.0 micron) shifts the 10, 11 micron features systematically towards longer wavelengths and relative to the 11 micron feature increases the strengths and slightly broadens the longer wavelength features. Seven spectral shape classes are established for crystallographic a-, b-, and c-axes and include columnar and platelet shapes plus non-elongated or equant grain shapes. The spectral shape classes and the effects of grain size have practical application in identifying or excluding columnar, platelet or equant forsterite grain shapes in astrophysical environs. Identification of the shape characteristics of forsterite from 8 - 40 micron spectra provides a potential means to probe the temperatures at which forsterite formed.

circumstellar matter↗
NASA NTRS2007

Implementation of the NASA AG-Bed Rest Pilot

To examine the efficacy of artificial gravity (AG) as a countermeasure to spaceflight deconditioning, intermittent AG produced by a horizontal short-radius centrifuge (SRC) was utilized on human test subjects deconditioned by bed rest. This poster will present the subject screening, study design, logistics, and implementation of the 41 day pilot study conducted at the University of Texas Medical Branch, Galveston, TX bed rest facility. An extensive screening process was employed to exclude subjects that were dissimilar to the U.S. astronaut population. Candidates underwent a modified U.S. Air Force Class III physical and tests of bone density, cardiovascular fitness, vestibular system function, psychological fitness and centrifuge tolerance. 15 subjects completed the study; 7 control and 8 AG treatment. All provided written consent to volunteer after the nature of the study and its hazards were clearly explained to them. Standard conditions were strictly regulated; Ta = 72 +/- 2 F, humidity = 70 +/- 5%, light/dark cycle 16h:8h. All fluid intake (minimum 28.5 ml/kg body weight/day) and urine output was monitored. Caloric intake was adjusted as necessary to maintain body weight. Carbohydrate, fat and protein were provided in a ratio of 55:30:15. Phosphorus intake was 1400 mg/d, sodium intake was 2 mmol/kg/d, potassium intake was 1.3 mmol/kg/d, and dietary calcium intake was 1000 mg/d. A physician examined each subject daily. During the first 11 days of the study protocol, subjects were ambulatory, but confined to the facility. Subjects participated in multiple baseline tests of bone, muscle, cardiovascular, sensory-motor, immunological, and psychological function. On the 12th day, subjects entered the bed rest phase of the study, during which they were confined to strict 6? head down tilt bed rest for 21 days. Beginning 24 hrs into this period, treatment subjects received 1 hour daily exposures to artificial gravity which was produced by spinning the subjects on a 3.0 m radius SRC. They were oriented radially in the supine position so that the centrifugal force was aligned with their long body axis, and while spinning, they #stood# on a force plate, supporting the centrifugal loading (2.5 g at the feet, 1.0 g at the heart). The subject station allowed free translation over approximately 10 cm to ensure full loading of the lower extremities and to allow for anti-orthostatic muscle contractions. Control subjects were positioned on the centrifuge but did not spin. Following the bed rest phase, subjects were allowed to ambulate again, but remained within the facility for an additional 9 days and participated in multiple follow-up tests of physiological function.

Warren, L. E.↗
NASA NTRS2008

8-Meter UV/Optical Space Telescope

This slide presentation proposes using the unprecedented capability of the planned Ares V launch vehicle, to place a 8 meter monolithic space telescope at the Earth-Sun L2 point. This new capability enables a new design pardigm -- simplicity. The six to eight meter class telescope with a massive high Technical Readiness Level ground observatory class monolithic primary mirror has been determined feasible. The proposed design, structural analysis, spacecraft design and shroud integration, thermal analysis, propulsion system, guidance navigation and pointing control assumptions about the avionics, and power systems, operational lifetime, and the idea of in-space servicing are reviewed.

Stahl, H. Philip↗
NASA NTRS2003

Basic and clinical immunology

Progress in immunology continues to grow exponentially every year. New applications of this knowledge are being developed for a broad range of clinical conditions. Conversely, the study of primary and secondary immunodeficiencies is helping to elucidate the intricate mechanisms of the immune system. We have selected a few of the most significant contributions to the fields of basic and clinical immunology published between October 2001 and October 2002. Our choice of topics in basic immunology included the description of T-bet as a determinant factor for T(H)1 differentiation, the role of the activation-induced cytosine deaminase gene in B-cell development, the characterization of CD4(+)CD25(+) regulatory T cells, and the use of dynamic imaging to study MHC class II transport and T-cell and dendritic cell membrane interactions. Articles related to clinical immunology that were selected for review include the description of immunodeficiency caused by caspase 8 deficiency; a case series report on X-linked agammaglobulinemia; the mechanism of action, efficacy, and complications of intravenous immunoglobulin; mechanisms of autoimmunity diseases; and advances in HIV pathogenesis and vaccine development. We also reviewed two articles that explore the possible alterations of the immune system caused by spaceflights, a new field with increasing importance as human space expeditions become a reality in the 21st century.

Review↗
NASA NTRS2020

FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5

The study of hot corinos in solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which therefore represents a crucial step in the future planetary system chemical composition. Hence, the study of hot corinos in Class I protostars has become of paramount importance. Here, we report the discovery of a hot corino towards the prototypical Class I protostar L1551 IRS5, obtained within the ALMA (Atacama Large Millimeter/submillimeter Array) Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). We detected several lines from methanol and its isotopologues (13CH3OH and CH2DOH), methyl formate, and ethanol. Lines are bright towards the north component of the IRS5 binary system, and a possible second hot corino may be associated with the south component. The methanol lines' non-LTE analysis constrains the gas temperature (∼100 K), density (≥1.5 × 10^8 per cu.cm), and emitting size (∼10 au in radius). All CH3OH and 13CH3OH lines are optically thick, preventing a reliable measure of the deuteration. The methyl formate and ethanol relative abundances are compatible with those measured in Class 0 hot corinos. Thus, based on this work, little chemical evolution from Class 0 to I hot corinos occurs.

astrochemistry, stars: formation, ISM: molecules↗
NASA NTRS2012

Extreme-Ultraviolet Spectroscopic Observation of Direct Coronal Heating During a C-Class Solar Flare

With the Coronal Diagnostic Spectrometer operating in rapid cadence (9.8 s) stare mode during a C6.6 flare on the solar disk, we observed a sudden brightening of Fe xix line emission (formed at temperature T ≈ 8 MK) above the pre-flare noise without a corresponding brightening of emission from ions formed at lower temperatures, including He i (0.01 MK), Ov (0.25 MK), and Si xii (2 MK). The sudden brightening persisted as a plateau of Fe xix intensity that endured more than 11 minutes. The Fe xix emission at the rise and during the life of the plateau showed no evidence of significant bulk velocity flows, and hence cannot be attributed to chromospheric evaporation. However, the line width showed a significant broadening at the rise of the plateau, corresponding to nonthermal velocities of at least 89 km s−1 due to reconnection outflows or turbulence. During the plateau He i, Ov, and Si xii brightened at successively later times starting about 3.5 minutes after Fe xix, which suggests that these brightenings were produced by thermal conduction from the plasma that produced the Fe xix line emission; however, we cannot rule out the possibility that they were produced by a weak beam of nonthermal particles. We interpret an observed shortening of the Ov wavelength for about 1.5 minutes toward the middle of the plateau to indicate new upward motions driven by the flare, as occurs during gentle chromospheric evaporation; relative to a quiescent interval shortly before the flare, the Ov upward velocity was around −10 km s−1.

Activity↗
NASA NTRS1996

Performance of Optimized Actuator and Sensor Arrays in an Active Noise Control System

Experiments have been conducted in NASA Langley's Acoustics and Dynamics Laboratory to determine the effectiveness of optimized actuator/sensor architectures and controller algorithms for active control of harmonic interior noise. Tests were conducted in a large scale fuselage model - a composite cylinder which simulates a commuter class aircraft fuselage with three sections of trim panel and a floor. Using an optimization technique based on the component transfer functions, combinations of 4 out of 8 piezoceramic actuators and 8 out of 462 microphone locations were evaluated against predicted performance. A combinatorial optimization technique called tabu search was employed to select the optimum transducer arrays. Three test frequencies represent the cases of a strong acoustic and strong structural response, a weak acoustic and strong structural response and a strong acoustic and weak structural response. Noise reduction was obtained using a Time Averaged/Gradient Descent (TAGD) controller. Results indicate that the optimization technique successfully predicted best and worst case performance. An enhancement of the TAGD control algorithm was also evaluated. The principal components of the actuator/sensor transfer functions were used in the PC-TAGD controller. The principal components are shown to be independent of each other while providing control as effective as the standard TAGD.

Palumbo, D. L.↗