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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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NASA NTRS2013

DMSP Auroral Charging at Solar Cycle 24 Maximum

It has been well established that polar orbiting satellites can experience mild to severe auroral charging levels (on the order of a few hundred volts to few kilovolts negative frame potentials) during solar minimum conditions. These same studies have shown a strong reduction in charging during the rising and declining phases of the past few solar cycles with a nearly complete suppression of auroral charging at solar maximum. Recently, we have observed examples of high level charging during the recent approach to Solar Cycle 24 solar maximum conditions not unlike those reported by Frooninckx and Sojka. These observations demonstrate that spacecraft operations during solar maximum cannot be considered safe from auroral charging when solar activity is low. We present a survey of auroral charging events experienced by the Defense Meteorological Satellite Program (DMSP) F16 satellite during Solar Cycle 24 maximum conditions. We summarize the auroral energetic particle environment and the conditions necessary for charging to occur in this environment, we describe how the lower than normal solar activity levels for Solar Cycle 24 maximum conditions are conducive to charging in polar orbits, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period.

Chandler, M.↗
NASA NTRS2013

DMSP Auroral Charging at Solar Cycle 24 Maximum

It has been well established that polar orbiting satellites can experience mild to severe auroral charging levels (on the order of a few hundred volts to few kilovolts negative frame potentials) during solar minimum conditions (Frooninckx and Sojka, 1992; Anderson and Koons, 1996; Anderson, 2012). These same studies have shown a strong reduction in charging during the rising and declining phases of the past few solar cycles with a nearly complete suppression of auroral charging at solar maximum. Recently, we have observed examples of high level charging during the recent approach to Solar Cycle 24 solar maximum conditions not unlike those reported by Frooninckx and Sojka (1992). These observations demonstrate that spacecraft operations during solar maximum cannot be considered safe from auroral charging when solar activity is low. We present a survey of auroral charging events experienced by the Defense Meteorological Satellite Program (DMSP) F16 satellite during Solar Cycle 24 maximum conditions. We summarize the auroral energetic particle environment and the conditions necessary for charging to occur in this environment, we describe how the lower than normal solar activity levels for Solar Cycle 24 maximum conditions are conducive to charging in polar orbits, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period.

Chandler, Michael↗
NASA NTRSDate not supplied

Pyroscopegridding: Geo-Leo Aerosol Data Fusion (an Open-Source Package)

The retrieval of aerosol optical depths (AODs) from sun-synchronous polar orbiting satellites, such as MODISs, VIIRSs, OMI, TROPOMI, etc., has been widely adopted as a method for obtaining information regarding particulate matter (PM) and related atmospheric processes. However, the advent of recently launched geostationary satellites, such as GOES-16/17/18, Himawari-8/9, and Meteosat Third Generation (MTG), has led to an increased temporal resolution of AOD observations (order of 10 minutes), resulting in typically one or more images per hour during daylight hours, compared to the once-per-day observations obtained from LEO satellites. By integrating these observations, the diurnal cycle of global AOD can be characterized at local, regional, and global scales. The scientific community is still examining the novel data from geostationary satellite observations and evaluating methods for effectively merging these observations with differing spatial and temporal resolutions. This presents a significant ""Big Data"" challenge, encompassing not only data storage, but also data discoverability, accessibility, and migration within cloud computing environments. This study presents our attempts at fusing Level 2 aerosol data from six satellites, three of which are geostationary (GOES-16/17 and Himawari-8) and three of which are polar orbiting (TERRA/MODIS, AQUA/MODIS, and SNPP-VIIRS), using the Dark Target aerosol retrieval algorithm. The ability to fuse remote sensing products on demand into desired temporal and spatial domains empowers researchers and practitioners to more efficiently work with satellite and sensor data. It is our hope that through making our open-source package and accompanying functionality available, the scientific community will have improved access to aerosol data processing resources.

Jennifer Wei↗
NASA NTRS2023

Aurora Detection From Nighttime Lights for Earth and Space Science Applications

This research leverages data from the Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer (VIIRS) instrument onboard the Suomi National Polar-orbiting Partnership (S-NPP) satellite. We demonstrate the value of mining the VIIRS DNB for aurora and describe our use of unsupervised machine learning to create a binary mask for aurora occurrence. This mask can be used to flag aurora-contaminated observations for NASA's nighttime lights products for Earth science applications. The identification of auroral regions can also be used for Space Weather applications, for example, for comparison with aurora forecast model and with other satellite- or ground-based aurora observations. The DNB is a broadband channel that is sensitive to wavelengths from 500 to 900 nm, which covers most of the visible light spectrum, and as the name implies, captures light even at night with a sensitivity at the nanowatt level. This band is suitable for aurora observations since the light emitted by the aurora tends to be dominated by emissions from atomic oxygen, resulting in a greenish glow at a wavelength of 557.7 nm, especially at an altitude of 110 km. This study compares the global nighttime derived aurora regions for 17 and 18 March with the NOAA Space Weather Prediction Center's (SWPC) probability product for the St. Patrick's Day geomagnetic storm in 2015. VIIRS sensors are slated to be added to the next generation of polar-orbiting operational satellites. Our novel automated approach to aurora identification opens up an efficient way to leverage this unique data source.

Aurora↗
NASA NTRS2022

Vicarious Calibration of the Long Near Infrared Band: Cross-Sensor Differences in Sensitivity

Numerous assumptions and approximations are employed when translating satellite-derived radiance to surface remote sensing reflectance (RRS) for ocean color applications. Among these is the vicarious calibration coefficient (g) of the “long” near infrared band (NIRL) used for atmospheric correction. For this band, the prelaunch calibration has always been deemed sufficient [thus g(NIRL) = 1.00] as long as other bands are vicariously calibrated. Recent research, however, suggests that Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua RRS time series is quite sensitive to g(NIRL) (and associated vicarious gains in other bands). In this work, we assessed the sensitivity of Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-orbiting Partnership satellite (VIIRS/SNPP) RRS to NIRL calibration and compared our results to previous MODIS/Aqua and Sea-viewing Wide Field-of-View Sensor onboard OrbView2 (SeaWiFS)/OrbView2 analysis. In doing so, we note that g(NIRL) sensitivities of mission-averaged RRS time series are lower for VIIRS and Sea-WiFS, relative to MODIS. At the scale of monthly climatologies (MCs), however, all sensors show prominent g(NIRL) sensitivity with that of SeaWiFS being the most substantial. These findings informed simulation analyses, whereby we identified signal-tonoise ratio (SNR) and radiant path geometry, as well as their interaction, as having notable impacts on g(NIRL) sensitivity. As such, g(NIRL) sensitivity is a necessary consideration for reflectance uncertainty budgets, especially for sensors with higher NIR SNR or particular prevailing radiant path geometries. Given the geometry components embedded within g(NIRL) sensitivity, such studies should be coupled with cross-sensor intercalibrations [e.g., using simultaneous same view (SSV) measurements] toward minimizing NIRL errors between satellite instruments, but such efforts will not completely remediate remaining cross-sensor biases in RRS. Index Terms—Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua, ocean color, ocean gyres, Sea-viewing Wide Field-of-View Sensor onboard OrbView2 (SeaWiFS), system vicarious calibration (SVC), Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-orbiting Partnership satellite (VIIRS/SNPP).

MODIS↗
NASA NTRS2017

Mitigating Satellite-Based Fire Sampling Limitations in Deriving Biomass Burning Emission Rates: Application to WRF-Chem Model over the Northern sub-Saharan African Region

Largely used in several independent estimates of fire emissions, fire products based on MODIS sensors aboard the Terra and Aqua polar-orbiting satellites have a number of inherent limitations, including (a) inability to detect fires below clouds, (b) significant decrease of detection sensitivity at the edge of scan where pixel sizes are much larger than at nadir, and (c) gaps between adjacent swaths in tropical regions. To remedy these limitations, an empirical method is developed here and applied to correct fire emission estimates based on MODIS pixel level fire radiative power measurements and emission coefficients from the Fire Energetics and Emissions Research (FEER) biomass burning emission inventory. The analysis was performed for January 2010 over the northern sub-Saharan African region. Simulations from WRF-Chem model using original and adjusted emissions are compared with the aerosol optical depth (AOD) products from MODIS and AERONET as well as aerosol vertical profile from CALIOP data. The comparison confirmed an 30-50% improvement in the model simulation performance (in terms of correlation, bias, and spatial pattern of AOD with respect to observations) by the adjusted emissions that not only increases the original emission amount by a factor of two but also results in the spatially continuous estimates of instantaneous fire emissions at daily time scales. Such improvement cannot be achieved by simply scaling the original emission across the study domain. Even with this improvement, a factor of two underestimations still exists in the modeled AOD, which is within the current global fire emissions uncertainty envelope. Plain Language Summary Polar-orbiting satellites sensors, such as MODIS, have limitations in detecting fires under clouds or when viewing angles are large or in the gaps among satellites' different ground swaths. Here we developed an empirical method to mitigate the effect of these limitations in fire emission estimate. The method is applied to a fire emission inventory (FEER) based on MODIS. We show that, with our method, the adjusted emission inventory improves WRF-Chem simulation of smoke transport and distribution.

emissions properties↗
NASA NTRSDate not supplied

NOAA-17 Break-up Engineering Investigation

The NOAA-17 weather satellite operated in polar orbit near 800 km from 2002 until it was decommissioned in April 2013. The spacecraft broke up almost eight years later in March 2021 producing about 100 trackable objects. This follows the breakups of similar spacecraft NOAA-16, DMSP F11, and DMSP F13 which also produced between 80 and 500 trackable objects. An investigation was made into the cause of the breakup and recommend how to better operate or decommission spacecraft in the future. The NOAA-17 breakup was found to be a single, localized debris event; there is likely no catastrophic damage to the whole spacecraft. NOAA-17 debris is very much in family with NOAA-16 debris, and DMSP F11 and F13 are very much in family with each other and share similarities with NOAA-16 and 17; it is likely all four share the same breakup cause. DMSP F13 breakup occurred simultaneous with a known battery overcharge and therefore battery rupture is most likely intermediate cause of all four of the breakups. This is a low confidence assessment, however, since other debris sources cannot be definitively ruled out. No root cause was found as the NOAA-17 batteries were all confirmed to have been disconnected from the charge path as intended. Possible conditions for reconnection are all unlikely including short circuits and ground commanding. All 25 related spacecraft pose a risk of similar breakups for decades to come and are a threat to the critical 800-850 km polar orbit regime; even appropriately decommissioned spacecraft appear to be at risk. Recommendations include an update to the decommissioning procedure and consideration of further investigations and active debris removal, consistent with national policy.

Scott Hull↗
NASA NTRS1975

Development of a stratospheric and mesospheric microwave temperature sounder experiment

A passive microwave spectrometer system for measuring global atmospheric temperature profiles from 0-75 km altitude was developed and analyzed. The system utilizes 12 channels near the 5 mm wavelength oxygen absorption band and is designed to provide global coverage by scanning perpendicular to the orbital track of a polar orbiting satellite. A significant improvement in the accuracy of theoretical atmospheric microwave transmittance functions was achieved through the development of a first-order approximation to overlapping line theory for the oxygen molecule. This approximation is particularly important in the troposphere and lower stratosphere where pressure-broadening blends nearby lines. Ground-based and aircraft observations of several resonances of stratospheric oxygen generally support the theory. The 23, 25, 29, and 31 atmospheric oxygen lines were measured and the frequencies of several such oxygen lines were measured with improved precision. The polarization and Zeeman splitting of the atmospheric 27 line was also observed.

Staelin, D. H.↗
DOE OSTI2022

Trigonal symmetry breaking and its electronic effects in the two-dimensional dihalides MX 2 and trihalides MX 3

We study the consequences of the approximately trigonal (D 3d ) point symmetry of the transition metal (M) site in two-dimensional van der Waals MX 2 dihalides and MX 3 trihalides. The trigonal symmetry leads to a 2-2-1 orbital splitting of the transition metal d shell, which is best represented by d orbitals that describe the trigonal rather than Oh symmetry. The ligand-ligand bond length differences (rather than metal-ligand) take the role of a Jahn-Teller-like mode and in combination with interlayer distances and dimensionality effects tune the crystal field splittings and bandwidths. These effects, in turn, are amplified by electronic correlation effects—leading to crystal field splittings of the order of 0.1–1 eV between the singlet and the lowest orbital doublet—as opposed to the often assumed degenerate 3 t 2g states. Our calculations explain why most of the materials in this family are insulating, and why these considerations have to be taken into account in realistic models of them. Further, orbital order coupled to various lower symmetry lattice modes may lift the remaining orbital degeneracies, and we explain how these may support unique electronic states using ZrI 2 and CuCl 2 as examples, and offer a brief overview of possible electronic configurations in this class of materials. By building and analyzing Wannier models adapted to the appropriate symmetry we examine how the interplay among trigonal symmetry, electronic correlation effects, and – d orbital charge transfer leads to insulating, orbitally polarized magnetic and/or orbital-selective Mott states, and we provide a simple framework and numerical tool for others. Our paper establishes a rigorous framework to understand, control, and tune the electronic states in low-dimensional correlated halides. Furthermore, our analysis shows that trigonal symmetry and its breaking is a key feature of the two-dimensional halides that needs to be accounted for in search of novel electronic states in materials ranging from CrI 3 to α–RuCl 3 .

2-dimensional systems↗
NASA NTRS1972

Seasonal and altitude variations in field-aligned precipitation occurrence

Data from more than 7500 orbits of the polar-orbiting satellite OGO-4 have been analyzed to determine the existence of seasonal, altitude, or universal time differences in the occurrence of field-aligned electrons. Unexpected variations in frequency of occurrence have been found at different altitudes and in different seasons. In particular, the probability of observing this phenomenon at high latitudes was found to be greatest in the winter months at the highest altitudes attained by OGO-4. A localized parallel electric field acceleration mechanism is presented which could account for the particle observations.

Berko, F. W.↗
NASA NTRS1973

Dependence of field-aligned electron precipitation on season, altitude and pitch angle

The occurrence of field-aligned 2.3 keV electron precipitation was examined by using data from more than 7500 orbits of the polar-orbiting satellite, OGO-4. The frequency of occurrence of field aligned precipitation was highest at actual pitch angles between 7 and 10 deg, being highest in the winter months, at highest satellite altitudes. Acceleration by a localized parallel electric field established by electrostatic charge layers is proposed to explain particle observations.

Berko, F. W.↗
NASA NTRS1974

Dependence of field-aligned electron precipitation occurrence on season and altitude

An examination of factors affecting the occurrence of field-aligned 2.3-keV electron precipitation has been performed by using data from more than 7500 orbits of the polar-orbiting satellite Ogo 4. Both season and altitude were found to be parameters that are directly related to the probability of occurrence. The highest probabilities occurred when the measurements were made at altitudes from 800 km to apogee (914 km), except during summer. In this altitude interval, the electron precipitation was more likely to be field-aligned during winter than during any other season. The analysis suggests the establishment by electrostatic charge layers of localized electric fields parallel to the magnetic field. The resulting potential distribution focuses the electron beam along the field lines in the region between the charge layers but destroys the focused beam below the lower layer, and thus an altitude dependence is created.

Berko, F. W.↗
NASA NTRS1976

Stabilizing influence of earth perturbations on polar lunar orbiters

A class of highly inclined lunar orbits is discussed for which earth perturbations have significant influence on the orbit evolution and the usefulness of the orbit for scientific exploration. The theory of the long-term motion of particles under third-body and zonal harmonic perturbations is taken as a starting point for investigations of orbits with relatively long lifetimes and evolutionary patterns that enhance the effectiveness of the satellite as a lunar farside relay. An equilibrium solution in the doubly-averaged three-body problem with oblateness is identified and the results of some numerical integrations are presented.

Uphoff, C.↗
NASA NTRS1990

Global digital topography mapping with a synthetic aperture scanning radar altimeter

Global digital topography data of the land surface is of importance in a variety of geoscientific and application disciplines. Such a database, with a spatial resolution of 150 to 500 m and height accuracy of 5 m or better can be acquired from an orbiting platform using a synthetic aperture scanning radar altimeter. Near-global coverage can be achieved within 14 days from an orbiting platform in a polar or near-polar orbit.

Elachi, C.↗
NASA NTRS1991

Lunar base siting

As with any planetary body, the lunar surface is quite heterogeneous. There are widely dispersed sites of particular interest for known and potential resource availability, selenology, and lunar observatories. Discriminating characteristics include solar illumination, view of earth, local topography, engineering properties of the regolith and certain geological features, and local mineralogy and petrology. Space vehicle arrival and departure trajectories constitute a minor consideration. Over time, a variety of base sites will be developed serving different purposes. Resource-driven sites may see the fastest growth during the first decades of lunar development, but selection of the most favorable sites is likely to be driven by suitability for a combination of activities. As on earth, later development may be driven by geographical advantages of surface transportation routes. With the availability of near-constant sunlight for power generation, as well as permanently shadowed areas at cryogenic temperatures, polar sites are attractive because they require substantially less earth-launched mass and lower equipment complexity for an initial permanent base. Discovery of accessible volatiles reservoirs, either in the form of polar permafrost or gas reservoirs at other locations, would dramatically increase the attractiveness of any site from a logistical support and selenological point of view. Amid such speculation, no reliable evidence of such volatiles exist. More reliable evidence exists for areas of certain mineral concentrations, such as ilmenite, which could form a feedstock for some proposed resource extraction schemes. While tentative selections of advantageous base sites are made, new data from lunar polar orbiters and the Galileo polar flybys would be very helpful.

Staehle, Robert L.↗
NASA NTRS1985

The WINDSAT concept for measuring the global wind field

The Wave Propagation Laboratory of the National Oceanic and Atmospheric Administration's (NOAA) Environmental Research Laboratories has investigated the feasibility of measuring the global wind field by using an infrared coherent laser radar under a joint program with the U.S. Air Force Space Division Defense Meteorological Satellite Program (DMSP). These studies considered both the analytical and hardware feasibility of a spaceborne global wind measuring coherent laser radar (WINDSAT). Objectives and requirements of the Air Force Defense Meteorological Satellite Program were used in the study. The vertical distributions of the horizontal wind field were required throughout the troposphere with 300 km square horizontal and 1 km vertical resolution with a measurements accuracy of 1 m/s. Complete global coverage was required. The lidar system performance should also be scalable to operational satellite conditions. The analytical studies were performed for both a 300 km altitude Space Shuttle orbit and an operational polar orbit of 800 km altitude (Huffaker, 1978; Huffaker et al., 1980). A hardware definition study was performed for a Space Shuttle demonstration test flight (Lockheed Missiles and Space Co., 1981). Studies have also been conducted to determine the feasibility of mounting a WINDSAT payload on an Advanced TIROS-N spacecraft (RCA Corporation, 1983).

Huffaker, R. Milton↗
NASA NTRS1994

The Lunar Scout Program: An international program to survey the Moon from orbit for geochemistry, mineralogy, imagery, geodesy, and gravity

The Lunar Scout Program was one of a series of attempts by NASA to develop and fly an orbiting mission to the moon to collect geochemical, geological, and gravity data. Predecessors included the Lunar Observer, the Lunar Geochemical Orbiter, and the Lunar Polar Orbiter - missions studied under the auspices of the Office of Space Science. The Lunar Scout Program, however, was an initiative of the Office of Exploration. It was begun in late 1991 and was transferred to the Office of Space Science after the Office of Exploration was disbanded in 1993. Most of the work was done by a small group of civil servants at the Johnson Space Center; other groups also responsible for mission planning included personnel from the Charles Stark Draper Laboratories, the Lawrence Livermore National Laboratory, Boeing, and Martin Marietta. The Lunar Scout Program failed to achieve new start funding in FY 93 and FY 94 as a result of budget downturns, the de-emphasis of the Space Exploration Initiative, and the fact that lunar science did not rate as high a priority as other planned planetary missions, and was cancelled. The work done on the Lunar Scout Program and other lunar orbiter studies, however, represents assets that will be useful in developing new approaches to lunar orbit science.

Morrison, Donald A.↗
NASA NTRS2009

Sizing of "Mother Ship and Catcher" Concepts for LEO Small Debris Capture

Most Low Earth Orbit (LEO) debris lies in a limited number of inclination "bands" associated with launch latitudes, or with specific useful orbit inclinations (such as polar orbits). Such narrow inclination bands generally have a uniform spread over all possible Right Ascensions of Ascending Node (RAANs), creating a different orbit plane for nearly every piece of debris. This complicates concept of rendezvous and capture for debris removal. However, a low-orbiting satellite will always phase in RAAN faster than debris objects in higher orbits at the same inclination, potentially solving the problem. Such a base can serve as a single space-based launch facility (a "mother ship") that can tend and then send tiny individual catcher devices for each debris object, as the facility drifts into the same RAAN as the higher object. This presentation will highlight characteristic system requirements of such an architecture, including structural and navigation requirements, power, mass and dV budgets for both the mother ship and the mass-produced common catcher devices that would clean out selected inclination bands. The altitude and inclination regime over which a band is to be cleared, the size distribution of the debris, and the inclusion of additional mission priorities all affect the sizing of the system. It is demonstrated that major LEO hazardous debris reductions can be realized in each band with a single LEO launch of a single mother ship, with simple attached catchers of total mass less than typical commercial LEO launch capability.

Bacon, John B.↗