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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Simultaneous impact and lunar craters

The existence of large terrestrial impact crater doublets and crater doublets that have been inferred to be impact craters on Mars suggests that simultaneous impact of two or more bodies can occur at nearly the same point on planetary surfaces. An experimental study of simultaneous impact of two projectiles near one another shows that doublet craters with ridges perpendicular to the bilateral axis of symmetry result when separation between impact points relative to individual crater diameter is large. When separation is progressively less, elliptical craters with central ridges and peaks, and circular craters with deep round bottoms are produced. These craters are similar in structure to many of the large lunar craters. Results suggest that the simultaneous impact of meteoroids near one another may be an important mechanism for the production of central peaks in large lunar craters.

Oberbeck, V. R.↗
NASA NTRS1985

Nd-isotopic evidence for the origin of the Sudbury complex by meteoritic impact

A Neodymium isotopic investigation was undertaken in order to determine the possibility that the Sudbury geological structure in Ontario, Canada was formed by meteoritic impact. Conclusive evidence points to the melting of crustal rocks by way of meteoritic impact in the forming of the Sudbury structure.

Faggart, B. E.↗
NASA NTRS1981

Optical deep space communication via relay satellite

The possible use of an optical for high rate data transmission from a deep space vehicle to an Earth-orbiting relay satellite while RF links are envisioned for the relay to Earth link was studied. A preliminary link analysis is presented for initial sizing of optical components and power levels, in terms of achievable data rates and feasible range distances. Modulation formats are restricted to pulsed laser operation, involving bot coded and uncoded schemes. The advantage of an optical link over present RF deep space link capabilities is shown. The problems of acquisition, pointing and tracking with narrow optical beams are presented and discussed. Mathematical models of beam trackers are derived, aiding in the design of such systems for minimizing beam pointing errors. The expected orbital geometry between spacecraft and relay satellite, and its impact on beam pointing dynamics are discussed.

Gagliardi, R. M.↗
NASA NTRS2008

Compression After Impact Testing of Sandwich Structures Using the Four Point Bend Test

For many composite laminated structures, the design is driven by data obtained from Compression after Impact (CAI) testing. There currently is no standard for CAI testing of sandwich structures although there is one for solid laminates of a certain thickness and lay-up configuration. Most sandwich CAI testing has followed the basic technique of this standard where the loaded ends are precision machined and placed between two platens and compressed until failure. If little or no damage is present during the compression tests, the loaded ends may need to be potted to prevent end brooming. By putting a sandwich beam in a four point bend configuration, the region between the inner supports is put under a compressive load and a sandwich laminate with damage can be tested in this manner without the need for precision machining. Also, specimens with no damage can be taken to failure so direct comparisons between damaged and undamaged strength can be made. Data is presented that demonstrates the four point bend CAI test and is compared with end loaded compression tests of the same sandwich structure.

Nettles, Alan T.↗
NASA NTRS1993

Landscape and geomorphic survey of Zhamanshin area, Northern Kazakhstan: Preliminary report on 1992 field trip data

The June 1992 geographical expedition to Zhamanshin crater area made a landscape and geomorphic survey of this impact structure. Observational points in the area of 300 sq km give new data on the geographical processes in the impact crater. The data obtained could be applied to search for unknown impact structures anywhere through the traces of such features in landscapes.

Burba, G. G., Jr.↗
NASA NTRS2014

The Bombardment History of 4 Vesta as Told by Sample Geochronology

The Dawn mission showed asteroid 4 Vesta to be an extensively cratered body, ancient in age, with craters in a variety of morphologies and preservation states [1-3]. Tying Vesta's relative crater ages to an absolute impact history can be accomplished through investigations of the HED (howardite, eucrite, diogenite) meteorites. Eucrites are crustal basalts and gabbros, diogenites are mostly orthopyroxenites representing lower crust or upper mantle materials, and howardites are mixed breccias containing both lithologies. Eucrite 53Mn-53Cr systematics show that the HED parent body globally differentiated by ~4.56 Ga and fully crystallized soon afterwards [4]. Much later, many eucrites were brecciated and heated by large impacts into the parent body surface. Disturbance ages in eucrites show that multiple large impacts occurred within 1 Gyr after crystallization, showing a history that largely resembles that of the Moon [5-7]. Dawn images also showed that Vesta is covered with a well-developed regolith that is spectrally similar to howardite meteorites [8]. Howardites are polymict regolith breccias made up mostly of clasts of eucrites and diogenites, but which also contain clasts formed by melting of the regolith by relatively large, energetic impact events. Impact-melt clast ages from howardites extend our knowledge of the impact history of Vesta, expanding on eucrite disturbance ages and helping give absolute age context to the observed crater-counts produced using Dawn data. The distribution of 40Ar-39Ar ages of impact-melt clasts in howardites shows that they formed within the time period 3.3-3.8 Ga [9]. These, and other impact-melted HED materials, have distinct age and compositional characteristics that suggest they formed in discrete impact events. In order to create these crystalline impact-melt products on the surface of Vesta, the impacts during this time period must have had velocities much higher than 5 km/s, the main belt average [10]. This is inconsistent with formation by a normal distribution of impact velocities and points instead to a unique period where high-velocity collisions were more frequent than currently observed. Until now, impact-reset ages in the HED meteorites have been be interpreted under the umbrella of the canonical lunar cataclysm where an increase in the absolute number of bombarding objects is responsible for creating larger absolute amounts of impact-affected and impact-melted rocks, statistically increasing their chances of being found on Earth and dated. However, the distribution of age among the howardite impact-melt clasts may not necessarily result from an increased number of impacts, but rather result from impacts of higher velocity. The changeover from a typical main belt velocity profile to this regime of increased velocity population at Vesta occurs contemporaneously with a similar transition at the Moon, indicating that howardite impact-melt clast ages reinforce the notion of a dynamically unusual episode of bombardment in the inner solar system beginning at around 4.0 Ga.

Cohen, B. A.↗
NASA NTRS2006

Near Sun Free-Space Optical Communications from Space

Free-space optical communications offers expanded data return capacity, from probes distributed throughout the solar system and beyond. Space-borne and Earth-based optical transceivers used for communicating optically, will periodically encounter near Sun pointing. This will result in an increase in the scattered background light flux, often contributing to degraded link performance. The varying duration of near Sun pointing link operations relative to the location of space-probes, is discussed in this paper. The impact of near Sun pointing on link performance for a direct detection photon-counting communications system is analyzed for both ground- and space-based Earth receivers. Finally, impact of near Sun pointing on spaceborne optical transceivers is discussed.

free-space↗
NASA NTRS1992

Large impacts in the Baltic shield with special attention to the Uppland structure

Within the Baltic Shield several very large structures have been identified and are suspected to be of meteorite impact origin. Some of these deeply eroded circular features are presented with special attention to the Uppland structure, where several indications point toward an impact origin in the mid-Proterozoic. The structures exceed 100 km in diameter and the topographic expression is inferior or absent. An arcuate arrangement of lithologies occurs around the margin of the structures and the central regions show conform magnetic and positive gravity anomalies. The Uppland structure is approximately 320 km in diameter as expressed by morphological, geological, and geophysical concentric patterns. The central part is topographically remarkably flat and is characterized by an unusual irregular fracture pattern. A subcircular central tonalite with density of 2.81 Mg(sup -3) gives a positive gravity anomaly of 35 mgal and the gravimetric profile is very similar to that of Manicouagan and Vredefort. The tonalite constitutes a huge antiform, 80 km in diameter, probably representing a 12-km structural uplift of infracrustal rocks. The flancs of the tonalite are characterized by recrystallized pseudotachylitic breccia dykes and breccia zones. Around the central parts amphibolite-grade metamorphic rocks appear as large fragments within a fine-grained granite interpreted as a thermally annealed melt rock. Several occurrences of breccia dykes and breccia-bearing melts have been identified about 100 km from the gravimetric center of the structure. Impact-related ore deposits are located around the margin of the structure and are interpreted as preexisting downfaulted iron formations, and deposits formed from remobilization of these preimpact occurrences. The so-called ball ores are interpreted to have formed by fluid injection similar to the formation of breccia dykes. The extensive hydrothermal alteration along the outer margin of the structure have created extreme soda and K-enriched rocks ('leptites') from preexisting gneiss granites and supracrustal sedimentary gneisses.

Henkel, H.↗
NASA NTRS1984

Insulation bonding test system

A method and a system for testing the bonding of foam insulation attached to metal is described. The system involves the use of an impacter which has a calibrated load cell mounted on a plunger and a hammer head mounted on the end of the plunger. When the impacter strikes the insulation at a point to be tested, the load cell measures the force of the impact and the precise time interval during which the hammer head is in contact with the insulation. This information is transmitted as an electrical signal to a load cell amplifier where the signal is conditioned and then transmitted to a fast Fourier transform (FFT) analyzer. The FFT analyzer produces energy spectral density curves which are displayed on a video screen. The termination frequency of the energy spectral density curve may be compared with a predetermined empirical scale to determine whether a igh quality bond, good bond, or debond is present at the point of impact.

Beggs, J. M.↗
NASA NTRSDate not supplied

Dose Error Impacts on A Collection of Realistic Dose-Response Curves Based on A NASA Sonic Boom Community Noise Survey

The National Aeronautics and Space Administration (NASA) plans to conduct surveys of community response to quiet supersonic flight to collect dose-response data for international regulators. Previous models of noise dose versus annoyance response ignored uncertainty in the noise dose experienced by survey respondents. This dose error causes attenuation bias and results in inaccurate dose-response relationships. The impacts of dose errors can be explored by introducing error into the dose estimates of a simulated community noise survey. The simulated population annoyance response is determined by specific noise response characteristics, including the onset of annoyance intercept, rate of increasing annoyance, participant intercept variability, and response rates. This paper explores the effects of dose errors on notional populations created by perturbing the noise response characteristics observed in participants in a recent NASA flight test, QSF18. The QSF18-based population parameters were shifted up to ±20% to create the study populations. For the anticipated dose range of the X-59, changes to the onset of annoyance intercept have the greatest impact on erroneous model results. Quantifying point estimate errors illustrates the impact of dose error, with errors up to 14 dB observed for a fixed high annoyance percentage.

dose-response modeling↗
NASA NTRSDate not supplied

Dose Error Impacts on A Collection of Realistic Dose-Response Curves Based on A NASA Sonic Boom Community Noise Survey

The National Aeronautics and Space Administration (NASA) plans to conduct surveys of community response to quiet supersonic flight to collect dose-response data for international regulators. Previous models of noise dose versus annoyance response ignored uncertainty in the noise dose experienced by survey respondents. This dose error causes attenuation bias and results in inaccurate dose-response relationships. The impacts of dose errors can be explored by introducing error into the dose estimates of a simulated community noise survey. The simulated population annoyance response is determined by specific noise response characteristics, including the onset of annoyance intercept, rate of increasing annoyance, participant intercept variability, and response rates. This paper explores the effects of dose errors on notional populations created by perturbing the noise response characteristics observed in participants in a recent NASA flight test, QSF18. The QSF18-based population parameters were shifted up to ±20% to create the study populations. For the anticipated dose range of the X-59, changes to the onset of annoyance intercept have the greatest impact on erroneous model results. Quantifying point estimate errors illustrates the impact of dose error, with errors up to 14 dB observed for a fixed high annoyance percentage.

dose-response modeling↗
NASA NTRSDate not supplied

Understanding the Response of Common Spacecraft Shields to Hypervelocity Impacts of Meteorite and Other Terrestrial Analog Materials

Micrometeoroid and orbital debris (MMOD) populations can vary significantly in composition, density, and homogeneity. Hypervelocity testing campaigns intended to design and optimize MMOD shields for spacecraft are recognizing the need to investigate shield response from different types of impactors that span the range of densities observed in the MMOD population, such as nylon, Al, Al 2 O 3 , steel, and Cu. These tests, however, still pre-dominantly employ spherical and homogenous projectiles. Adding any compositional or mineralogical complexity to the impactor, such as what would be expected from a polymineralic micrometeoroid, for ex-ample, will be concomitant with a more complex shockwave structure in the projectile after it impacts the outer surface of any type of MMOD shield. The magnitude of these complexities will depend on how varied the mineralogy of the projectile is, but in the case of a metal-bearing chondrite, the disparate shock impendence between adjacent metal and silicate grains will potentially create localized areas of shock focusing (local increase in nominal shock pressure), or shock shadowing (local decrease in nominal shock pressure). The response of a MMOD shield is generally predicted using a ballistic limit equation – a semiempirical curve, derived from hypervelocity testing data, that denotes a particle diameter (for a given set of impact conditions such as projectile density and impact angle) when a shield will fail as a function of impact speed. These curves exhibit inflection points as a function of impact speed that represent when the projectile experiences sufficient pressure to fragment, melt, or vaporize. The introduction of shock focusing and shadowing in a heterogenous projectile will add uncertainty to the predicted pressures needed to go through each transition, leading to increased uncertainty in the expected performance of the MMOD shield. Therefore, it is necessary to explore the performance of MMOD shields in hypervelocity tests against more complex, natural projectile materials. To this end we have conducted a comparative test series to begin investigating the impact damage caused by meteoritic and terrestrial-analog projectiles, to that of spherical Al projectiles of similar mass.

Impact testing↗
NASA NTRS2011

Assessing the Impact of Advanced Satellite Observations in the NASA GEOS-5 Forecast System Using the Adjoint Method

The adjoint of a data assimilation system provides a flexible and efficient tool for estimating observation impacts on short-range weather forecasts. The impacts of any or all observations can be estimated simultaneously based on a single execution of the adjoint system. The results can be easily aggregated according to data type, location, channel, etc., making this technique especially attractive for examining the impacts of new hyper-spectral satellite instruments and for conducting regular, even near-real time, monitoring of the entire observing system. In this talk, we present results from the adjoint-based observation impact monitoring tool in NASA's GEOS-5 global atmospheric data assimilation and forecast system. The tool has been running in various off-line configurations for some time, and is scheduled to run as a regular part of the real-time forecast suite beginning in autumn 20 I O. We focus on the impacts of the newest components of the satellite observing system, including AIRS, IASI and GPS. For AIRS and IASI, it is shown that the vast majority of the channels assimilated have systematic positive impacts (of varying magnitudes), although some channels degrade the forecast. Of the latter, most are moisture-sensitive or near-surface channels. The impact of GPS observations in the southern hemisphere is found to be a considerable overall benefit to the system. In addition, the spatial variability of observation impacts reveals coherent patterns of positive and negative impacts that may point to deficiencies in the use of certain observations over, for example, specific surface types. When performed in conjunction with selected observing system experiments (OSEs), the adjoint results reveal both redundancies and dependencies between observing system impacts as observations are added or removed from the assimilation system. Understanding these dependencies appears to pose a major challenge for optimizing the use of the current observational network and defining requirements for future observing systems.

Gelaro, Ron↗
NASA NTRS2006

Abnormal/Emergency Situations. Impact of Unmanned Aircraft Systems Emergency and Abnormal Events on the National Airspace System

Access 5 analyzed the differences between UAS and manned aircraft operations under five categories of abnormal or emergency situations: Link Failure, Lost Communications, Onboard System Failures, Control Station Failures and Abnormal Weather. These analyses were made from the vantage point of the impact that these operations have on the US air traffic control system, with recommendations for new policies and procedures included where appropriate.

Source record↗
NASA NTRSDate not supplied

Quantification of Design Trade-Offs When Comparing Transonic Truss-Braced Wing to Advanced Tube and Wing Aircraft

Interest in novel aircraft configurations has continued to grow in response to increasing demand for improved fuel efficiency. One such configuration of interest is the Transonic Truss-Braced Wing (TTBW). Because the improvement of the TTBW comes from increased efficiency during cruise, it offers increasing returns as the mission distance increases. As a result, there is often a crossover point which represents the minimum mission range where the TTBW will offer a fuel burn reduction relative to a similar Tube and Wing aircraft with similar component technology levels. Aircraft rarely fly missions at their maximum range, so it is important to investigate not only the maximum benefit, but also the most likely benefit. Design decisions and analysis assumptions that significantly impact this crossover point include whether to put fuel in body tanks, how weight build-up estimation is calibrated, engine technology selection, and flight Mach number. This study, conducted under NASA’s Sustainable Flight Demonstration project and inspired by differing assumptions made by different research teams, details the impacts of changing these design decisions and assumptions.

Carl J Recine↗
NASA NTRSDate not supplied

Quantification of Design Trade-Offs When Comparing Transonic Truss-Braced Wing to Advanced Tube and Wing Aircraft

Interest in novel aircraft configurations has continued to grow in response to increasing demand for improved fuel efficiency. One such configuration of interest is the Transonic Truss-Braced Wing (TTBW). Because the improvement of the TTBW comes from increased efficiency during cruise, it offers increasing returns as the mission distance increases. As a result, there is often a crossover point which represents the minimum mission range where the TTBW will offer a fuel burn reduction relative to a similar Tube and Wing aircraft with similar component technology levels. Aircraft rarely fly missions at their maximum range, so it is important to investigate not only the maximum benefit, but also the most likely benefit. Design decisions and analysis assumptions that significantly impact this crossover point include whether to put fuel in body tanks, how weight build-up estimation is calibrated, engine technology selection, and flight Mach number. This study, conducted under NASA’s Sustainable Flight Demonstration project and inspired by differing assumptions made by different research teams, details the impacts of changing these design decisions and assumptions.

Carl J Recine↗
NASA NTRSDate not supplied

The Zircon-Reidite Shock Transformation: A Tem Study of Reidite Produced at A Newly Established 21.2 GPa Shock Pressure Threshold

The high-pressure polymorph of zircon (Zr2SiO4) is reidite, a phase with the scheelite structure that was first discovered to form at ca. 12 GPa in static high-pressure experiments [1]. Reidite was subsequently found to occur in naturally shocked zircons from several terrestrial impact localities [2,3], as well as in shock recovery-reverberation experiments performed above 20 GPa [4]. The nature and distribution of reidite occurrences in terrestrial impact localities has pointed to its potential use as a shock pressure indicator, as well as to the importance of understanding its age-reset effects in zircon geochronology [3]. In this study we have used coordinated SEM/Electron Backscatter Diffraction (EBSD) and Field-Emission Scanning Transmission Electron Microscopy (FE-STEM) to study the micro- and nanostructure of reidite and its shocked zircon host produced at 21.2 GPa under experimental shock recovery/reverberation conditions [5]. Our results document the TEM microstructure of reidite formed at a 21.2 GPa experimental shock pressure that is significantly lower than that observed in previous studies [4]. At these conditions the sample developed a diverse set of microstructures that have not been previously documented on the TEM scale.

shock metamorphism↗
NASA NTRS1973

Measuring and minimizing the social cost of environmental pollution

The various impacts to the environmental protection movement on the largest corporations in several industries which had the most serious pollution problem are discussed. The purpose was to examine the impacts from the point of view of top corporation managers so that a broader perspective could be provided for all concerned parties- citizens, environmentalists, legislators, governmental administrators and agency personnel, scientists, engineers, and other industrial managers.

Henry, H. W.↗