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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Research and technology Fiscal Year 1985 report

A quarter of a century is but a moment on the cosmic calendar. Now that Marshall Space Flight Center has reached its 25th Anniversity, it seems just moments ago that President Dwight D. Eisenhower stood on these grounds and formally dedicated the George C. Marshall Space Flight Center in Huntsville, Alabama. The Fiscal Year 1985 Research and Technology Report reflects the wide spectrum of activities closely linked with the Center's mainstream spaceflight developments. Past accomplishments testify to the success of getting deeply involved in the science and technology of its projects - 32 Saturn launches, Pegasus, the Skylab missions, three High Energy Astronomy Observatory missions, the Apollo - Soyuz mission, and an accelerating schedule of successful Shuttle, Spacelab, and Shuttle payload missions. The Center continues to be involved in engineering development, scientific research, and technology. At the beginning of the second quarter century, the experience and dedication of the engineers and scientists, and the success of the collaboration with industry and academia will now be aimed at the next great endeavor, the Space Station.

Speer, F.↗
NASA NTRS2015

Thermal Testing and Integration: Magnetospheric MultiScale (MMS) Observatories with Digital 1-Wire Sensors

Thermocouples require two thin wires to be routed out of the spacecraft to connect to the ground support equipment used to monitor and record the temperature data. This large number of wires that exit the observatory complicates integration and creates an undesirable heat path during testing. These wires exiting the spacecraft need to be characterized as a thermal short that will not exist during flight. To minimize complexity and reduce thermal variables from these ground support equipment (GSE) wires, MMS pursued a hybrid path for temperature monitoring, utilizing thermocouples and digital 1-wire temperature sensors. Digital 1-wire sensors can greatly reduce harness mass, length and complexity as they can be spliced together. For MMS, 350 digital 1-wire sensors were installed on the spacecraft with only 18 wires exiting as opposed to a potential 700 thermocouple wires. Digital 1-wire sensors had not been used in such a large scale at NASAGSFC prior to the MMS mission. During the MMS thermal vacuum testing a lessons learned matrix was formulated that will assist future integration of 1-wires into thermal testing and one day into flight.

Sensors↗
NASA NTRS2018

Interactive Multi-Instrument Database of Solar Flares

The fundamental motivation of the project is that the scientific output of solar research can be greatly enhanced by better exploitation of the existing solar/heliosphere space-data products jointly with ground-based observations. Our primary focus is on developing a specific innovative methodology based on recent advances in "big data" intelligent databases applied to the growing amount of high-spatial and multi-wavelength resolution, high-cadence data from NASA's missions and supporting ground-based observatories. Our flare database is not simply a manually searchable time-based catalog of events or list of web links pointing to data. It is a preprocessed metadata repository enabling fast search and automatic identification of all recorded flares sharing a specifiable set of characteristics, features, and parameters. The result is a new and unique database of solar flares and data search and classification tools for the Heliophysics community, enabling multi-instrument/multi-wavelength investigations of flare physics and supporting further development of flare-prediction methodologies.

Heliophysics↗
NASA NTRS2022

Phosphine in the Venusian Atmosphere: A Strict Upper Limit from SOFIA GREAT Observations

The presence of phosphine (PH3) in the atmosphere of Venus was reported by Greaves et al. based on observations of the J = 1–0 transition at 267 GHz using ground-based, millimeter-wave spectroscopy. This unexpected discovery presents a challenge for our understanding of Venus's atmosphere, and has led to a reappraisal of the possible sources and sinks of atmospheric phosphorous-bearing gases. Here we present results from a search for PH3 on Venus using the German REceiver for Astronomy at Terahertz Frequencies instrument aboard the Stratospheric Observatory for Infrared Astronomy aircraft, over three flights conducted in November 2021. Multiple PH3 transitions were targeted at frequencies centered on 533 and 1,067 GHz, but no evidence for atmospheric PH3 was detected. Through radiative transfer modeling, we derived a disk-averaged upper limit on the PH3 abundance of 0.8 ppb in the altitude range 75–110 km, which is more stringent than previous ground-based studies.

M. A. Cordiner↗
NASA NTRS2001

Ecological Niches for Space Missions in the Far-Infrared

The far-infrared and submillimeter region (30 micrometers-750 micrometers) has perhaps the greatest potential of all wavelengths for advancement in astronomy. When viewed in terms of the cosmic backgrounds, the fares is extremely important: half of the total luminosity in the Universe is emitted at rest wavelengths approximately 80 - 100 micrometers. At the highest known galaxy redshifts (z approximately equal to 6) this energy is redshifted to approximately 600 micrometers. Existing and planned survey missions have a broad range of capabilities, defined in terms of their spectral coverage, spectral resolution, survey area, and sensitivity. In this 4-dimensional parameter space, the flares is found to be substantially behind most other wavelength bands. The opportunity for future missions with great discovery potential is evident. Such missions will be wellsuited to answering fundamental questions about the history of energy release in the Universe, the formation and evolution of galaxies, and formation of stellar and protoplanetary systems. We discuss the parameter space that can be filled by a few well-chosen space missions, specifically a submillimeter all-sky survey and a far-IR to submillimeter observatory.

Benford, Dominic J.↗
DOE OSTI2023

Machine Learning Downscaling of SoilMERGE in the United States Southern Great Plains

SoilMERGE (SMERGE) is a root-zone soil moisture (RZSM) product that covers the entire continental United States and spans 1978 to 2019. Machine learning techniques, Random Forest (RF), eXtreme Gradient Boosting (XGBoost), and Gradient Boost (GBoost) downscaled SMERGE to spatial resolutions straddling the field scale domain (100 to 3000 m). Study area was northern Oklahoma and southern Kansas. The coarse resolution of SMERGE (0.125 degree) limits this product’s utility. To validate downscaled results in situ data from four sources were used that included: United States Department of Energy Atmospheric Radiation Measurement (ARM) observatory, United States Climate Reference Network (USCRN), Soil Climate Analysis Network (SCAN), and Soil moisture Sensing Controller and oPtimal Estimator (SoilSCAPE). In addition, RZSM retrievals from NASA’s Airborne Microwave Observatory of Subcanopy and Surface (AirMOSS) campaign provided a nearly spatially continuous comparison. Three periods were examined: era 1 (2016 to 2019), era 2 (2012 to 2015), and era 3 (2003 to 2007). During eras 1 and 2, RF outperformed XGBoost and GBoost, whereas during era 3 no model dominated. Performance was better during eras 1 and 2 as opposed to the pre-L band era 3. Improvements across all eras, regions, and models realized from downscaling included an increase in correlation from 0.03 to 0.42 and a decrease in ub RMSE from -0.0005 to -0.0118 m 3 /m 3 . This study demonstrates the feasibility of SMERGE downscaling opening the prospect for the development of a long-term RZSM dataset at a more desirable field-scale resolution with the potential to support diverse hydrometeorological and agricultural applications.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1998

New Mysteries at Chiron

Considered as a comet, Chiron is unusual in two respects: (1) it exhibits outbursts at great distances from the sun (nearly up to its aphelion distance of 18.9 AU), and (2) its nucleus is much larger than any other known comet. It is similar in size, however, to the recently discovered Kuiper belt objects, leading to the conjecture that Chiron is closely related to these objects, but its chaotic orbit has brought it much closer to the sun. Our work with the Kuiper Airborne Observatory resulted in the first stellar occultation by Chiron observed simultaneously at visible and infrared wavelengths. We detected four features in the coma, with different degrees of certainty. Our conclusions about Chiron from this work and a previous stellar occultation are: (1) the jet-like features observed provide evidence that the coma material originates from just a few, small active areas, rather than uniform sublimation; (2) a bound coma has possibly been detected; (3) the particle radii in at least one of the jet-like features are larger than 0.25 gm; (4) material in Chiron's orbit plane has likely been detected; and (5) the radius of Chiron's nucleus lies between 83 and 156 km.

Elliot, James L.↗
NASA NTRS2004

Maximizing Science Capability for Far-Infrared Space Missions

The far-infrared and submillimeter region (20 microns-800 microns) has perhaps the greatest potential of all wavelengths for advancement in astronomy. When viewed in terms of the cosmic backgrounds, the far-IR is extremely important: half of the total luminosity in the Universe is emitted at rest wavelengths approximately 80-100 microns. At the highest known galaxy redshifts (z approximately equal to 6) this energy is redshifted to approximately 600 microns. Existing and planned missions have a broad range of capabilities, defined in terms of their spectral coverage, spectral resolution, angular resolution, mapping speed, and sensitivity. In this 5-dimensional parameter space, the far-IR is substantially be-hind most other wavelength bands. The opportunity for future missions with great discovery potential is evident. Such missions will be well-suited to answering fundamental questions about the history of energy release in the Universe, the formation and evolution of galaxies, and formation of stellar and protoplanetary systems. We discuss the parameter space that can be filled by a few well-chosen space missions, specifically a submillimeter all-sky survey and a far-IR to submillimeter observatory. Ultimately, a long baseline submillimeter interferometer is necessary to provide sensitivity and angular resolution.

Benford, Dominic↗
NASA NTRS2022

Mars 2020 Entry, Descent, and Landing as Observed by Radio Science Techniques at UHF and X-band Frequencies

On February 18, 2021, NASA’s Mars 2020 Rover “Perseverance” conducted the Entry, Descent, and Landing (EDL) sequence to land safely on the surface of Mars at Jezero Crater. Due to the criticality of the EDL sequence, redundant telecommunications strategies were utilized to observe the event. The rover transmitted an X-band (8.4 GHz) signal encoded with Multiple Frequency Shift Keying tones direct-to-Earth and a UHF (401.5 MHz) signal with 8 kbps encoded telemetry to orbiters, which relayed the signal back to Earth at X-band. NASA’s Deep Space Network complexes at Goldstone, California and Madrid, Spain received the direct-to-Earth X-band signal. Two of the largest steerable radio telescopes in the world, the 100-meter Green Bank Telescope in West Virginia and the Effelsberg 100-meter Radio Telescope in Germany also received the UHF carrier signal on Earth. During the EDL event, full spectrum recordings of the UHF and X-band signals were captured at these observatories using open-loop receivers. Real-time and post-processing signal analysis to determine power level, received frequency, and Doppler shift allowed determination of the spacecraft’s health and safety state during critical sequences, including event detection such as atmospheric entry, plasma blackouts, and parachute deployment. Simultaneous observations of the UHF and X-band radio links allow for redundancy in the event of a fault and greatly improve confidence in Doppler event detection.

Gladden, Roy↗
DOE OSTI2020

Examining the Ice-Nucleating Particles from the Southern Great Plains Field Campaign Report

The recent U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility field campaign, named Examining the Ice-Nucleating Particles from Southern Great Plains (ExINP-SGP), targeted experimentally characterizing abundance and other properties of ambient ice-nucleating particles (INPs) at the SGP site in Oklahoma (36° 36' 18" N, 97° 29' 6" W) during the period of October 1 to November 14, 2019. This campaign was funded through the DOE Office of Science Early Career Research Program (DE-SC0018979) as one of three major campaigns to be conducted at three ARM observatories, including the Eastern North Atlantic (ENA) station in 2020–2021 and North Slope of Alaska (NSA) site in 2021–2023, besides SGP. Different INP episodes were assessed to develop an SGP-relevant ice nucleation parameterization that would help understand convective and mixed-phase cloud systems typically observed in this region.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1993

Nonthermal processes around collapsed objects: High energy gamma ray sources in the radio sky

In our proposal responding to the initial Guest Observer NRA for the Compton Gamma Ray Observatory, 'Nonthermal Processes Around Collapsed Objects: High Energy Gamma Ray Sources in the Radio Sky', we stated that 'At high energies - the identity of the principal Galactic source population remains unknown' although the 'one certain source of high energy emission is young radio pulsars'. These two statements remain true, although at this writing, eighteen months after the beginning of the Compton allsky survey, much of the gamma-ray data required to greatly extend our knowledge of the Galaxy's high energy emission has been collected. The thrust of the program supported by our grant was to collect and analyze a complementary set of data on the Milky Way at radio wavelengths in order to help identify the dominant Pop 1 component of the Galaxy's gamma ray sources, and to pursue theoretical investigations on the origins and emission mechanisms of young pulsars, the one component of this population identified to date. We summarize here our accomplishments under the grant. In Section 2, we describe our VLA surveys of the Galactic Plane along with the current status of the radio source catalogs derived therefrom; unfortunately, owing to the TDRSS antenna problem and subsequent extension of the Sky Survey, we were not able to carry out a comparison with the EGRET data directly, although everything is now in place to do so as soon as it becomes available. In Section 2, we summarize our progress on the theoretical side, including the substantial completion of a dissertation on pulsar origins and work on the high energy emission mechanisms of isolated pulsars. We list the personnel supported by the grant in section 4 and provide a complete bibliography of publications supported in whole or in part by the grant in the final section.

Helfand, David J.↗
NASA NTRS2002

Science Goal Driven Observing and Spacecraft Autonomy

Spacecraft autonomy will be an integral part of mission operations in the coming decade. While recent missions have made great strides in the ability to autonomously monitor and react to changing health and physical status of spacecraft, little progress has been made in responding quickly to science driven events. For observations of inherently variable targets and targets of opportunity, the ability to recognize early if an observation will meet the science goals of a program, and react accordingly, can have a major positive impact on the overall scientific returns of an observatory and on its operational costs. If the onboard software can reprioritize the schedule to focus on alternate targets, discard uninteresting observations prior to downloading, or download a subset of observations at a reduced resolution, the spacecraft's overall efficiency will be dramatically increased. The science goal monitoring (SGM) system is a proof- of-concept effort to address the above challenge. The SGM will have an interface to help capture higher-level science goals from the scientists and translate them into a flexible observing strategy that SGM can execute and monitor. We are developing an interactive distributed system that will use on-board processing and storage combined with event-driven interfaces with ground-based processing and operations, to enable fast re-prioritization of observing schedules, and to minimize time spent on non-optimized observations. This paper will focus on our strategy for developing SGM and the technical challenges that we have encountered. We will discuss the SGM architecture as it applies to the proposed MIDEX-class mission Kronos. However, the architecture and interfaces will also be designed for easy adaptability to other observing platforms, including ground-based systems and to work with different scheduling and pipeline processing systems.

Jones, Jeremy↗
NASA NTRS2002

Science Goal Driven Observing and Spacecraft Autonomy

Spacecraft autonomy will be an integral part of mission operations in the coming decade. While recent missions have made great strides in the ability to autonomously monitor and react to changing health and physical status of spacecraft, little progress has been made in responding quickly to science driven events. For observations of inherently variable targets and targets of opportunity, the ability to recognize early if an observation will meet the science goals of a program, and react accordingly, can have a major positive impact on the overall scientific returns of an observatory and on its operational costs. If the onboard software can reprioritize the schedule to focus on alternate targets, discard uninteresting observations prior to downloading, or download a subset of observations at a reduced resolution, the spacecraft's overall efficiency will be dramatically increased. The science goal monitoring (SGM) system is a proof-of-concept effort to address the above challenge. The SGM will have an interface to help capture higher level science goals from the scientists and translate them into a flexible observing strategy that SGM can execute and monitor. We are developing an interactive distributed system that will use on-board processing and storage combined with event-driven interfaces with ground-based processing and operations, to enable fast re-prioritization of observing schedules, and to minimize time spent on non-optimized observations.

Koratkar, Amuradha↗
NASA NTRS1980

Spectrophotometric observations of P/Schwassmann-Wachmann 1 during outburst

Spectra of Comet Schwassmann-Wachmann 1 were obtained on November 26-27, 1978 and February 15, 1979 using the Cassegrain Digicon spectrograph, and on February 21-23, 1979 using the IDS spectrograph of McDonald Observatory. All spectra were obtained while the comet was in an extended series of outburst (12th-13th mag). The spectra were predominantly reflected solar light, indicating the outburst was very rich in dust. Weak emission between 4000 and 4050 A, and between 4240 and 4290 A was detected in November 1978 and is probably due to CO(+). These outbursts, and the detection of CO(+), indicate that comets are not inactive at distances as great as 6 AU.

Cochran, A. L.↗
NASA NTRS1984

Far Infrared Spectroscopy of (O III) in M82

Emission lines at 52 and 88 micron from O III in the galaxy M82 were observed with the cooled grating spectrometer aboard the Kuiper Airborne Observatory. Raw spectra were corrected for telluric water vapor absorption, instrument response function, and relative detector response by ratioing to a spectrum of Saturn or Mars taken on the same flight. An average electron density Pn regions where oxygen is doubly ionized was derived. The electron density calculated for M 82 is significantly lower than those found in the galaxy using the same method. Results suggest that observations of the galaxy made from a great distance would yield a higher electron density than observed in M82.

Duffy, P.↗
NASA NTRS2005

Submillimeter Spectroscopy with SOFIA

Four submillimeter spectrometers are being developed for use on SOFIA, the Stratospheric Observatory for Infrared Astronomy. They will be nearly diffraction limited by SOFIA'S 2.5 m telescope, giving for example images of 8.5 arc seconds FWHM at 100 microns. The instruments are FlFI LS, an integral-field imaging grating spectrometer (MPE) covering 40-210 microns with ~150 km/s resolution; SAFIRE an imaging Fabry-Perot spectrometer covering 100-'650 microns with resolution ~200 km/s, and two heterodyne receivers with resolving powers up to ~0.03 km/s: GREAT covering bands from 158-187 um, 110-125, and 62-65 microns, and CASIMIR, operating from 150-264 and 508-588 microns. These instruments will enable a variety of studies including topics relating to the origins of stars, planets, and biogenic materials in the interstallar medium of our own and other galaxies. Opportunities for observing with these and the other SOFIA instruments will be available to general investigators. SOFIA is a joint project of NASA in the U.S. and DLR in Germany.

Erickson, E.↗
DOE OSTI2022

Photometric Redshifts for Next-Generation Surveys

Photometric redshifts are essential in studies of both galaxy evolution and cosmology, as they enable analyses of objects too numerous or faint for spectroscopy. The Rubin Observatory, Euclid, and Roman Space Telescope will soon provide a new generation of imaging surveys with unprecedented area coverage, wavelength range, and depth. To take full advantage of these data sets, further progress in photometric redshift methods is needed. In this review, we focus on the greatest common challenges and prospects for improvement in applications of photometric redshifts to the next generation of surveys: ∙ Gains in performance (i.e., the precision of redshift estimates for individual galaxies) could greatly enhance studies of galaxy evolution and some probes of cosmology. ∙ Improvements in characterization (i.e., the accurate recovery of redshift distributions of galaxies in the presence of uncertainty on individual redshifts) are urgently needed for cosmological measurements with next-generation surveys. To achieve both of these goals, improvements in the scope and treatment of the samples of spectroscopic redshifts that make high-fidelity photometric redshifts possible will also be needed. For the full potential of the next generation of surveys to be reached, the characterization of redshift distributions must improve by roughly an order of magnitude compared with the current state of the art, requiring progress on a wide variety of fronts. We conclude by presenting a speculative evaluation of how photometric redshift methods and the collection of the necessary spectroscopic samples may improve by the time near-future surveys are completed.

Astronomy & Astrophysics↗
NASA NTRS1986

Epsilon Aurigae in eclipse. II - Optical absorption lines from the secondary

Optical high-resolution 2.7-m McDonald Observatory observations of Epsilon Aur obtained during the 1982-1985 eclipse are discussed, with focus on the K I resonance lines, some Fe II and Ti II lines in the blue, and the near-infrared N I excitation lines. The N I lines are immune to contamination by the secondary, and their radial velocity decline over the three-year interval fits the predicted velocity curve. The 7664 A and 7699 A K I lines strengthen greatly during the eclipse due to gas in orbit around the secondary passing in front of the primary, and the velocity pattern analysis indicates a mass of the secondary to solar mass ratio of between about 3 and 6 and a primary mass of 3 solar masses. The data are consistent with the picture of a low-mass post-AGB primary having lost mass through a wind and by Roche-lobe transfer to the secondary, and which will evolve to a white dwarf in less than 10,000 years.

Lambert, D. L.↗