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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Skyfall: Signal Fusion from a Smartphone Falling from the Stratosphere

A smartphone plummeted from a stratospheric height of 36 km, providing a near-real-time record of its rapid descent and ground impact. An app recorded and streamed useful internal multi-sensor data at high sample rates. Signal fusion with external and internal sensor systems permitted a more detailed reconstruction of the Skyfall chronology, including its descent speed, rotation rate, and impact deceleration. Our results reinforce the potential of smartphones as an agile and versatile geophysical data collection system for environmental and disaster monitoring IoT applications. We discuss mobile environmental sensing capabilities and present a flexible data model to record and stream signals of interest. The Skyfall case study can be used as a guide to smartphone signal processing methods that are transportable to other hardware platforms and operating systems.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Acoustic Rocket Signatures Collected by Smartphones

Rockets generate complex acoustic signatures that can be detected over a thousand kilometers from their source. While many far-field acoustic rocket signatures have been collected and released to the public, very few signatures collected at distances less than 100 km are available. This work presents a curated and annotated dataset of acoustic signatures of 243 rocket launches collected by a network of smartphones stationed at distances between 10 and 70 km from the launch sites, resulting in 1089 individual recordings. Due to the frequency dependence of atmospheric attenuation and the relatively short propagation distances, higher-frequency features not preserved in most publicly available data are observed. The signals are time-aligned to allow for different segments of the signal (ignition, launch, trajectory, chronology) to be more easily examined and compared. Initial analysis of the features of these rocket launch stages is performed, observed features are compared to those found in the existing literature, and comparisons between signals from launches of different rocket types are made. The dataset is annotated and made available to the public to aid future analysis of the characteristics and source mechanisms of rocket acoustics as well as applications such as rocket detection and classification models.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Policy Innovation and Governance for Irrigation Sustainability in the Arid, Saline San Joaquin River Basin

This paper provides a chronology and overview of events and policy initiatives aimed at addressing irrigation sustainability issues in the San Joaquin River Basin (SJRB) of California. Although the SJRB was selected in this case study, many of the same resource management issues are being played out in arid, agricultural regions around the world. The first part of this paper provides an introduction to some of the early issues impacting the expansion of irrigated agriculture primarily on the west side of the San Joaquin Valley and the policy and capital investments that were used to address salinity impairments to the use of the San Joaquin River (SJR) as an irrigation water supply. Irrigated agriculture requires large quantities of water if it is to be sustained, as well as supply water of adequate quality for the crop being grown. The second part of the paper addresses these supply issues and a period of excessive groundwater pumping that resulted in widespread land subsidence. A joint federal and state policy response that resulted in the facilities to import Delta water provided a remedy that lasted almost 50 years until the Sustainable Groundwater Management Act of 2014 was passed in the legislature to address a recurrence of the same issue. The paper describes the current state of basin-scale simulation modeling that many areas, including California, are using to craft a future sustainable groundwater resource management policy. The third section of the paper deals with unique water quality issues that arose in connection with the selenium crisis at Kesterson Reservoir and the significant threats to irrigation sustainability on the west side of the San Joaquin Valley that followed. The eventual policy response to this crisis was incremental, spanning two decades of University of California-led research programs focused on finding permanent solutions to the salt and selenium contamination problems constraining irrigated agriculture, primarily on the west side. Arid-zone agricultural drainage-induced water quality problems are becoming more ubiquitous worldwide. One policy approach that found traction in California is an innovative variant on the traditional Total Maximum Daily Load (TMDL) approach to salinity regulation, which has features in common with a scheme in Australia’s Hunter River Basin. The paper describes the real-time salinity management (RTSM) concept, which is geared to improving coordination of west side agricultural and wetland exports of salt load with east side tributary reservoir release flows to improve compliance with river salinity objectives. RTSM is a concept that requires access to continuous flow and electrical conductivity data from sensor networks located along the San Joaquin River and its major tributaries and a simulation model-based decision support designed to make salt load assimilative capacity forecasts. Web-based information dissemination and data sharing innovations are described with an emphasis on experience with stakeholder engagement and participation. The last decade has seen wide-scale, global deployment of similar technologies for enhancing irrigation agriculture productivity and protecting environmental resources.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

The Optical and Infrared Are Connected

Galaxies are often modeled as composites of separable components with distinct spectral signatures, implying that different wavelength ranges are only weakly correlated. They are not. We present a data-driven model that exploits subtle correlations between physical processes to accurately predict infrared (IR) Wide-field Infrared Survey Explorer (WISE) photometry from a neural summary of optical Sloan Digital Sky Survey spectra. The model achieves accuracies of $χ^{2}_{N} ≈ 1$ for all photometric bands in WISE, as well as good colors. We are able to tightly constrain typically IR-derived properties, e.g., the bolometric luminosities of active galactic nuclei (AGN) and dust parameters such as q PAH . We also test whether current spectral energy distribution (SED) fitting methods reproduce such panchromatic relations, but find their predictions biased and overconfident, likely due to model misspecification, with correlated biases in star-formation rates (SFRs) and AGN luminosities being most evident. To help improve SED models, we determine which features of the optical spectrum are responsible for our improved predictions, and identify several lines (Ca II , Sr II , Fe I , [O II ], and Hα), which point to the complex chronology of star formation and chemical enrichment being incorrectly modeled.

Jespersen, Christian Kragh [Princeton Univ., NJ (U↗
DOE OSTI2022

The Timing of Potential Last Nucleosynthetic Injections into the Protosolar Molecular Cloud Inferred from 41 Ca– 26 Al Systematics of Bulk CAIs

Short-lived radionuclides (SLRs) provide important information about the chronology of the early solar system. Among them, 41 Ca, due to its decay to 41 K with a half-life of only 0.1 Ma, is particularly valuable in constraining the timescales and origins of both SLRs and the formation of the oldest solar system materials, the Ca–Al-rich inclusions (CAIs). The initial abundance of 41Ca in the solar system, expressed as the ( 41 Ca/ 40 Ca)I ratio, is the key to unveiling the origin of this nuclide. Here, we report a new solar system ( 41 Ca/ 40 Ca)I ratio of 2.0 × 10 −8 derived from the K isotope compositions of two CAIs. This new ratio is about four times higher than the previous value inferred from a mineral isochron. Such a high ( 41 Ca/ 40 Ca)I ratio in the CAIs exceeds that expected for the protosolar molecular cloud by ∼1000×, implying very late injection of the 41 Ca (and possibly other SLRs) into the protosolar molecular cloud. The correlated enrichments of 41 Ca and 26 Al in the bulk CAI samples hint at a common stellar origin of both SLRs. The injection time estimated from our new data depends on the stellar source—it ranges from 0.6 Ma for a Wolf–Rayet wind to 1.0 Ma for a TP-AGB star ejecta.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Planetesimal Impact Vapor Plumes and Nebular Shocks Form Chondritic Mixtures

The origin of chondrules and the chondritic sedimentary rocks that dominate the meteoritic record is a long-standing problem in planetary science. Here, we develop a physical model for the formation of chondritic mixtures as an outcome of vaporizing collisions between planetesimals that were dynamically excited by the growth and migration of planets. We present calculations of nebular shock waves generated by impact vapor plumes and focus on aspects of the plume interaction with the nebular gas and dust that have been neglected in previous studies of impact ejecta. We find that when water dominates the vapor, the plumes are relatively cool. However, the plume expansion is supersonic and can drive strong shock waves in the dusty nebular gas. Portions of these nebular shock fronts initially melt nebular dust, forming chondrules that are coupled to the moving front. As the shock front expands and cools, the chondrules solidify, while the shock front entrains additional dust. Eventually, the plume expansion stalls and then hydrodynamically collapses, turbulently mixing variably processed dust and size-sorted chondrules. For probable impact parameters and nebular conditions during giant planet growth and migration, the impact-generated mixtures have characteristics that span the range observed in chondritic meteorites, providing an environment for rapid formation of chondritic assemblages after chondrule formation. Our impact vapor and nebular shocks model, named the IVANS model, links chondrule formation to the overall context of planet formation and provides a framework for interpreting the detailed chronological and geochemical record contained in chondritic meteorites.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

Glaciers preserve climate variations in their geological and geomorphological records, which makes them prime candidates for climate reconstructions. Investigating the glacier–climate system over the past millennia is particularly relevant first because the amplitude and frequency of natural climate variability during the Holocene provides the climatic context against which modern, human-induced climate change must be assessed. Second, the transition from the last glacial to the current interglacial promises important insights into the climate system during warming, which is of particular interest with respect to ongoing climate change. Evidence of stable ice margin positions that record cooling during the past 12 kyr are preserved in two glaciated valleys of the Silvretta Massif in the eastern European Alps, the Jamtal (JAM) and the Laraintal (LAR). We mapped and dated moraines in these catchments including historical ridges using beryllium-10 surface exposure dating (10Be SED) techniques and correlate resulting moraine formation intervals with climate proxy records to evaluate the spatial and temporal scale of these cold phases. The new geochronologies indicate the formation of moraines during the early Holocene (EH), ca. 11.0 ± 0.7 ka (n = 19). Boulder ages along historical moraines (n = 6) suggest at least two glacier advances during the Little Ice Age (LIA; ca. 1250–1850 CE) around 1300 CE and in the second half of the 18th century. An earlier advance to the same position may have occurred around 500 CE. The Jamtal and Laraintal moraine chronologies provide evidence that millennial-scale EH warming was superimposed by centennial-scale cooling. The timing of EH moraine formation coincides with brief temperature drops identified in local and regional paleoproxy records, most prominently with the Preboreal Oscillation (PBO) and is consistent with moraine deposition in other catchments in the European Alps and in the Arctic region. This consistency points to cooling beyond the local scale and therefore a regional or even hemispheric climate driver. Freshwater input sourced from the Laurentide Ice Sheet (LIS), which changed circulation patterns in the North Atlantic, is a plausible explanation for EH cooling and moraine formation in the Nordic region and in Europe.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

East Antarctic Ice Sheet variability in the central Transantarctic Mountains since the mid Miocene

The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to amplified melting coupled with dynamic instabilities or whether such losses will be balanced, or even offset, by enhanced accumulation under a higher-precipitation regime. The glacial depositional record from the central Transantarctic Mountains (TAM) provides a robust geologic means to reconstruct the past behaviour of the East Antarctic Ice Sheet, including during periods thought to have been warmer than today, such as the mid-Pliocene Warm Period (~3.3–3.0 Ma). This study describes a new surface-exposure-dated moraine record from Otway Massif in the central TAM spanning the last ~9 Myr and synthesises these data in the context of previously published moraine chronologies constrained with cosmogenic nuclides. The resulting record, although fragmentary, represents the majority of direct and unambiguous terrestrial evidence for the existence and size of the East Antarctic Ice Sheet during the last 14 Myr, and it thus provides new insight into the long-term relationship between the ice sheet and global climate. At face value, the existing TAM moraine record does not exhibit a clear signature of the mid-Pliocene Warm Period, thus precluding a definitive verdict on the East Antarctic Ice Sheet's response to this event. In contrast, an apparent hiatus in moraine deposition both at Otway Massif and the neighbouring Roberts Massif suggests that the ice sheet surface in the central TAM was potentially lower than present during the late Miocene and earliest Pliocene.

58 GEOSCIENCES↗
DOE OSTI2024

Cosmogenic 21 Ne exposure ages on late Pleistocene moraines in Lassen Volcanic National Park, California, USA

We report new cosmogenic 21 Ne in quartz exposure ages from 18 samples on three distinct moraines deposited in the Lost Creek drainage, approximately 3–7 km down-valley from Lassen Peak in Lassen Volcanic National Park. Although measuring 21 Ne in quartz is generally straightforward, accurate 21Ne exposure dating of deposits of late Pleistocene is rarely possible due to the significant quantities of non-cosmogenic 21 Ne present in most lithologies. Young quartz-bearing volcanic rocks have been observed to be an exception. We take advantage of moraine boulders sourced from the ~28 ka dacite of Lassen Peak to generate a chronology of alpine deglaciation in Lassen Volcanic National Park. Ages from three distinct moraines are in stratigraphic order at 22.1 ± 3.8, 20.2 ± 2.4, and 15.3 ± 3.8 ka and generally agree with other terminal and some recessional moraine ages across the Cascade Range and Sierra Nevada of the western United States. To date, these are among the youngest surfaces ever dated using cosmogenic 21 Ne and provide a cost-effective proof-of-concept approach to dating moraines where applicable.

58 GEOSCIENCES↗
DOE OSTI2022

The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating

Deglaciation of the northwestern Laurentide Ice Sheet in the central Mackenzie Valley opened the northern portion of the deglacial Ice-Free Corridor between the Laurentide and Cordilleran ice sheets and a drainage route to the Arctic Ocean. In addition, ice sheet saddle collapse in this section of the Laurentide Ice Sheet has been implicated as a mechanism for delivering substantial freshwater influx into the Arctic Ocean on centennial timescales. However, there is little empirical data to constrain the deglaciation chronology in the central Mackenzie Valley where the northern slopes of the ice saddle were located. Here, we present 30 new 10Be cosmogenic nuclide exposure dates across six sites, including two elevation transects, which constrain the timing and rate of thinning and retreat of the Laurentide Ice Sheet in the area. Our new 10Be dates indicate that the initial deglaciation of the eastern summits of the central Mackenzie Mountains began at ~15.8 ka (17.1–14.6 ka), ~1000 years earlier than in previous reconstructions. The main phase of ice saddle collapse occurred between ~14.9 and 13.6 ka, consistent with numerical modelling simulations, placing this event within the Bølling–Allerød interval (14.6–12.9 ka). Our new dates require a revision of ice margin retreat dynamics, with ice retreating more easterly rather than southward along the Mackenzie Valley. In addition, we quantify a total sea level rise contribution from the Cordilleran–Laurentide ice saddle region of ~11.2 m between 16 and 13 ka.

58 GEOSCIENCES↗
NASA NTRS1964

Thermal testing of the Ranger Block III SPACECRAFT in the JPL 25 ft. space simulator

In January, 1964, a test program was begun on the thermal design of the Ranger Block III Spacecraft. The tests were performed i n the newly operational JPL 25' Space Simulator over a period of 6 months . The objectives of these tests were two-fold: A. To evaluate the 25' Space Simulator as a facility for proving the thermal design of spacecrafts, and B. To verify .the thermal design of the Ranger Block III spacecraft. These two objectives are complimentary in the test series performed and are difficult to separate into distinct categories. An important part of the first objective was to learn what type of test preparation, instrumentation, and analysis was required for the meaningful evaluation of test data from the 25' Space Simulator tests. Although some experience had been gained in testing of components and incomplete spacecrafts in smaller solar simulation chambers during the early part of the Ranger program, we knew little about testing of a complete spacecraft in the 25' Space Simulator when this test program began. Test analysis requires that the energy absorbed by various spacecraft components be known. This requires a knowledge of the area of solar absorption or sunlit area, the solar energy flux density on the area, and the effective absorptance of that area. Most of the problems encountered were associated with the determination of the last two quantities since the sunlit area may be obtained directly by inspection of spacecraft surfaces. This paper will present a discussion of our experiences during the Ranger Block III thermal test series on the Thermal Test Model (TCM). The TCM was thermally equivalent to the flight type Ranger spacecraft except for the lack of an antenna dish and solar panels. Flight type structural hardware was used with surface finishes equivalent to those of the flight spacecraft. Aluminum blocks simulated the spacecraft electronics thermal masses with resistance heaters simulating the electronic power dissipation. The discussion will be presented in a semi-chronological order and will be divided into the following areas: 1. Determination of solar simulation flux density on spacecraft surfaces. 2. Problems related to decollimation of the solar simulation source. 3. Determination of effective absorptance in the solar simulation spectrum.

SPACE SIMULATOR↗
NASA NTRS1967

Astronautics and Aeronautics, 1966

At the opening of the tenth year in the era of man’s mobility in outer space, we can look back on 1966 as offering convincing evidence that the United States had gained great competence. This evidence included: five orbital space flights by ten Gemini astronauts; four lunar missions undertaking the orbiting of and soft landing on the moon; numerous contributions to scientific knowledge by unmanned spacecraft and sounding rockets; and further demonstrations of the practical utility of operational space systems, including weather and communications satellites. During 1966, a record 100 American spacecraft were placed into earth orbit or on escape trajectories. Thousands of revealing and useful pictures of the earth were taken from space and of the moon from lunar orbit and on its surface. The Gemini program ended with rendezvous and docking experiments and extravehicular activity by the Gemini test pilots as the Apollo R&D test flights leading to the manned lunar mission came into the schedule. Thirty-five major scientific, technological, and operational milestones were cited for 1966 by the President in his Report to the Congress on aeronautical and space activities of the United States. This was one measure of the American commitment to share in the peaceful exploration of space for all mankind. Another was our support of the final steps toward a United Nations space treaty, undertaken to ensure that the peaceful exploitation of space had juridical basis in international law. Spectacular as some events in the space venture were in 1966, they nonetheless came to have diminished novelty in the eyes of many laymen. The multitude of both important and unspectacular space activities attained almost an accepted and routine place. This volume, as well as its predecessor chronicles, offers a ready reference on the major as well as the less-well known events. Beyond the welter of documented details on the complex nature of aeronautical and space related events and their impact, this volume helps to provide a better perspective upon today as we contemplate tomorrow. Such intent also serves future historians and analysts who cannot be unmindful of what is herein presented. When the Congress created the National Aeronautics and Space Administration in 1958, it charged NASA with the responsibility to “contribute materially to . . . the expansion of human knowledge of phenomena in the atmosphere and space’’ and to “provide for the widest practical and appropriate dissemination of information concerning its activities and results thereof.” NASA has attempted to do this and to include documentation for the historical record. The relating of NASA history begins with this day-by day chronicle and leads to more specialized studies and histories of the unprecedented task of extending man’s mobility and understanding beyond his planet. While a chronology cannot in itself serve as a full-fledged history, the size of this annual volume alone is illustrative of the scope and complexity of the historical task yet to be completed as memories fade and the records disappear.

SPACE PROBE↗
NASA NTRS1968

Circuit detects voltage decrease in computer power supply

Rapid-response monitoring circuit detects voltage decrease or dropout in any single phase or all three phases simultaneously of a 3-phase 60 Hz computer power supply. It uses lamps to indicate voltage conditions and provides a digital pulse output for a chronological record of voltage irregularities.

Houck, W. H.↗