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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 NTRS2018

Formation Timescales of Amosphous Rims on Lunar Grains Derived from ARTEMIS Observations

The weathering of airless bodies exposed to space is a fundamental process in the formation and evolution of planetary surfaces. At the Moon, space weathering induces a variety of physical, chemical, and optical changes including the formation of nanometer-sized amorphous rims on individual lunar grains. These rims are formed by vapor redeposition from micrometeoroid impacts and ion irradiation-induced amorphization of the crystalline matrix. For ion irradiation-induced rims, however, laboratory experiments of the depth and formation timescales of these rims stand in stark disagreement with observations of lunar soil grains. We use observations by the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) spacecraft in orbit around the Moon to compute the mean ion flux to the lunar surface between 10 eV and 5 MeV and convolve this flux with ion irradiation-induced vacancy production rates as a function of depth calculated using the Stopping Range of Ions in Matter model. By combining these results with laboratory measurements of the critical fluence for charged-particle amorphization in olivine, we can predict the formation timescale of amorphous rims as a function of depth in olivinic grains. This analysis resolves two outstanding issues: (1) the provenance of >100 nm amorphous rims on lunar grains and (2) the nature of the depth-age relationship for amorphous rims on lunar grains.

Amorphous Rims↗
NASA NTRS2018

Global Soil Moisture Estimation from L-Band Satellite Data: The Impact of Radiative Transfer Modeling in Assimilation and Retrieval Systems

The SMOS and SMAP missions have collected a wealth of global L-band Brightness temperature (Tb) observations. The retrieval of surface Soil moisture estimates, and the estimation of other geophysical Variables, such as root-zone soil moisture and temperature, via data Assimilation into land surface models largely depends on accurate Radiative transfer modeling (RTM). This presentation will focus on various configuration aspects of the RTM (i) for the inversion of SMOS Tb to surface soil moisture, and (ii) for the forward modeling as part of a SMOS Tb data assimilation System to estimate a consistent set of geophysical land surface Variables, using the GEOS-5 Catchment Land Surface Model.

De Lannoy, Gabrielle↗
NASA NTRS2017

Spontaneous Hot Flow Anomalies at Mars and Venus

We report the first observations of Spontaneous Hot Flow Anomalies (SHFAs) at Venus and Mars, demonstrating their existence in the foreshocks of other planets beyond Earth. Using data from the ESA Venus Express and the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we present magnetic and plasma observations from events at both planets, exhibiting properties similar to “classical” Hot Flow Anomalies, with bounding shock-like compressive regions and a hot and diffuse core. However, these explosive foreshock transients were observed without any attendant interplanetary magnetic field discontinuity, consistent with SHFAs observed at Earth and our hybrid simulations.

Collinson, Glyn A.↗
NASA NTRS2017

Maven Observations of Tail Current Sheet Flapping at Mars

The Martian magnetotail is a complex regime through which atmospheric particles are lost to space. Our current understanding of Mars' tail continues to develop with the comprehensive particle and field data collected by Mars Atmosphere and Volatile EvolutioN (MAVEN). In this work, we identify periods when MAVEN encounters multiple current sheet crossings through a single tail traversal in order to understand tail dynamics. We apply an analysis technique that has been developed and validated by using multipoint measurements in order to separate the spatial and temporal properties associated with current sheet flapping. Events are classified into periods of steady flapping, due to a global motion of the current sheet, and kink-like flapping, resulting from localized wave propagation along the tail current sheet. Out of 106 periods during which multiple current sheet crossings were observed, 20 were due to steady flapping and 10 from kink-like flapping. A majority of the kink-like events resulted from waves propagating in the opposite direction of the solar wind convection electric field, regardless of their location in the tail, unlike at Earth and Venus. This finding suggests that possible magnetosphere energy sources, whereby plasma is accelerated and removed from the Martian environment, are not located in the central magnetotail; rather, these waves may be driven by a source located at the tail flank based on the direction of the solar wind electric field. Therefore, by identifying potential sources of impulsive energy release in the tail, we may better understand mechanisms that drive atmospheric loss at Mars.

Atmospheric Particles↗
NASA NTRS2016

Understanding Seasonal Variability in Thin Cirrus Clouds from Continuous MPLNET Observations at GSFC in 2012

Optically thin cirrus cloud (optical depth < 0.3) net radiative forcing represents one of the primary uncertainties in climate feedback, as sub-visible clouds play a fundamental role in atmospheric radiation balance and climate change. A lidar is a very sensitive optical device to detect clouds with an optical depth as low as 10-4. In this paper we assess the daytime net radiative forcing of sub-visible cirrus clouds detected at Goddard Space Flight Center, a permanent observational site of the NASA Micro Pulse Lidar Network in 2012. Depending on their height, season and hour of the day, the solar albedo effect can outweigh the infrared greenhouse effect, cooling the earth atmosphere system rather than warming it exclusively. As result, based on latitude, the net forcing of sub-visible cirrus clouds can be more accurately parameterized in climate models.

Lolli, Simone↗
NASA NTRS2012

Lunar Precursor Effects in the Solar Wind and Terrestrial Magnetosphere

The two ARTEMIS probes observe significant precursor activity upstream from the Moon, when magnetically connected to the dayside lunar surface. The most common signature consists of high levels of whistler wave activity near half of the electron cyclotron frequency. This precursor activity extends to distances of many thousands of km, in both the solar wind and terrestrial magnetosphere. In the magnetosphere, electrons reflect from a combination of magnetic and electrostatic fields above the lunar surface, forming loss cone distributions. In the solar wind they generally form conics, as a result of reflection from an obstacle moving with respect to the plasma frame (just as at a shock). The anisotropy associated with these reflected electrons provides the free energy source for the whistlers, with cyclotron resonance conditions met between the reflected source population and Moonward-propagating waves. These waves can in turn affect incoming plasma, and we observe significant perpendicular electron heating and plasma density depletions in some cases. In the magnetosphere, we also observe broadband electrostatic modes driven by beams of secondary electrons and/or photoelectrons accelerated outward from the surface. We also occasionally see waves near the ion cyclotron frequency in the magnetosphere. These lower frequency waves, which may result from the presence of ions of lunar origin, modulate the whistlers described above, as well as the electrons. Taken together, our observations suggest that the presence of the Moon leads to the formation of an upstream region analogous in many ways to the terrestrial electron foreshock.

Magnetosphere↗
NASA NTRS2018

The Small Satellite Reliability Initiative: A Public-Private Effort Addressing SmallSat Mission Confidence

Presently, most CubeSat components and buses are generally not appropriate for missions where significant or indeterminate risk of failure is unacceptable. This has precluded their use in many cases where their attributes could otherwise enable or enhance mission objectives. However, in the future, CubeSats and SmallSats, which deviate from CubeSat form factors but often incorporate CubeSat components and subsystems, will address challenges that many presently consider to be beyond the platform's capabilities. This growing potential utility, combined with the limited volume of successful CubeSat flight heritage, is driving an interagency effort to improve small satellite mission confidence.

SmallSat↗
NASA NTRS2018

The Twisted Configuration of the Martian Magnetotail: MAVEN Observations

Measurements provided by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft are analyzed to investigate the Martian magnetotail configuration as a function of interplanetary magnetic field (IMF) BY. We find that the magnetotail lobes exhibit a ~45deg twist, either clockwise or counterclockwise from the ecliptic plane, up to a few Mars radii downstream. Moreover, the associated cross-tail current sheet is rotated away from the expected location for a Venus-like induced magnetotail based on nominal IMF draping. Data-model comparisons using magnetohydrodynamic simulations are in good agreement with the observed tail twist. Model field line tracings indicate that a majority of the twisted tail lobes are composed of open field lines, surrounded by draped IMF. We infer that dayside magnetic reconnection between the crustal fields and draped IMF creates these open fields and may be responsible for the twisted tail configuration, similar to what is observed at Earth.

Martian↗
NASA NTRS2018

The Three-Dimensional Bow Shock of Mars as Observed by MAVEN

The Martian magnetosphere is a product of the interaction of Mars with the interplanetary magnetic field and the supersonic solar wind. The location of the bow shock has been previously modeled as conic sections using data from spacecraft such as Phobos 2, Mars Global Surveyor, and Mars Express. The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission spacecraft arrived in orbit about Mars in November 2014 resulting in thousands of crossings to date. We identify over 1,000 bow shock crossings. We model the bow shock as a three-dimensional surface accommodating asymmetry caused by crustal magnetic fields. By separating MAVEN's bow shock encounters based on solar condition, we also investigate the variability of the surface. We find that the shock surface varies in shape and location in response to changes in the solar radiation, the solar wind Mach number, dynamic pressure of the solar wind, and the relative local time location of the strong crustal magnetic fields (i.e., whether they are on the dayside or on the nightside).

Supersonic↗
NASA NTRS2018

Solar Wind Induced Waves in the Skies of Mars: Ionospheric Compression, Energization, and Escape Resulting from the Impact of Ultralow Frequency Magnetosonic Waves Generated Upstream of the Martian Bow Shock

Using data from the National Aeronautics and Space Administration Mars Atmosphere and Voltatile EvolutioN and the European Space Agency Mars Express spacecraft, we show that transient phenomena in the foreshock and solar wind can directly inject energy into the ionosphere of Mars. We demonstrate that the impact of compressive ultralow frequency waves in the solar wind on the induced magnetospheres drive compressional, linearly polarized, magnetosonic ultralow frequency waves in the ionosphere, and a localized electromagnetic "ringing" at the local proton gyro frequency. The pulsations heat and energize Ionospheric plasmas. A preliminary survey of events shows that no special upstream conditions are required in the interplanetary magnetic field or solar wind. Elevated ion densities and temperatures in the solar wind near to Mars are consistent with the presence of an additional population of Martian ions, leading to ion-ion instabilities, associated wave-particle interactions, and heating of the solar wind. The phenomenon was found to be seasonal, occurring when Mars is near perihelion. Finally, we present simultaneous multipoint observations of the phenomenon, with the Mars Express observing the waves upstream, and Mars Atmosphere and Voltatile EvolutioN observing the response in the ionosphere. When these new observations are combined with decades of previous studies, they collectively provide strong evidence for a previously undemonstrated atmospheric loss process at unmagnetized planets: ionospheric escape driven by the direct impact of transient phenomena from the foreshock and solar wind.

Collinson, Glyn↗
NASA NTRS2014

Regional Characteristics of the Relationship Between Columnar AOD and Surface PM2.5: Application of Lidar Aerosol Extinction Profiles over Baltimore-Washington Corridor During DISCOVER-AQ

The first field campaign of DISCOVER-AQ (Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality) took place in July 2011 over Baltimore-Washington Corridor (BWC). A suite of airborne remote sensing and in-situ sensors was deployed along with ground networks for mapping vertical and horizontal distribution of aerosols. Previous researches were based on a single lidar station because of the lack of regional coverage. This study uses the unique airborne HSRL (High Spectral Resolution Lidar) data to baseline PM2.5 (particulate matter of aerodynamic diameter less than 2.5 μm) estimates and applies to regional air quality with satellite AOD (Aerosol Optical Depth) retrievals over BWC (∼6500 sq. km). The linear approximation takes into account aerosols aloft above AML (Aerosol Mixing Layer) by normalizing AOD with haze layer height (i.e., AOD/HLH). The estimated PM2.5 mass concentrations by HSRL AOD/HLH are shown within 2 RMSE (Root Mean Square Error ∼9.6 μg/cu. m) with correlation ∼0.88 with the observed over BWC. Similar statistics are shown when applying HLH data from a single location over the distance of 100 km. In other words, a single lidar is feasible to cover the range of 100 km with expected uncertainties. The employment of MPLNET-AERONET (MicroPulse Lidar NETwork - AErosol RObotic NETwork) measurements at NASA GSFC produces similar statistics of PM2.5 estimates as those derived by HSRL. The synergy of active and passive remote sensing aerosol measurements provides the foundation for satellite application of air quality on a daily basis. For the optimal range of 10 km, the MODIS-estimated PM2.5 values are found satisfactory at 27 (out of 36) sunphotometer locations with mean RMSE of 1.6-3.3 μg/cu. m relative to PM2.5 estimated by sunphotometers. The remaining 6 of 8 marginal sites are found in the coastal zone, for which associated large RMSE values ∼4.5-7.8 μg/cu. m are most likely due to overestimated AOD because of water-contaminated pixels.

DISCOVER-AQ↗
NASA NTRS2018

Verification of an Icosahedral Grid for Strategic Center for Networking, Communications, and Integration User Interface Spatial Capabilities

Spatial communication analysis tools are incredibly useful resources to have when planning a space mission. Every single mission that leaves Earth needs a way to get its data back down and every mission's requirements on how that will get accomplished is different. Being able to analyze how existing assets can provide services independent of a specific mission can be key in that process. Most current commercial software packages contain spatial analysis capabilities but go about the analysis in a way that is not the most efficient and can skew the results provided. NASA's Space Communication and Navigation (SCaN) Center for Engineering Networks, Integration, and Communications (SCENIC) seeks to solve this problem and provide analysis capabilities using both internally developed and open-source software. This allows incredible flexibility, customization and hugely reduces licensing costs. Using MATLAB® and Orbit Determination Toolbox created by Goddard Space Flight Center (GSFC), SCENIC is able to perform many node-based functions currently. Analysis utilizing the spatial tools in SCENIC allows a meaningful analysis of the capability of communication network assets in a way not seen in current commercial software packages. This paper discusses the verification activities associated with generating the spatial grid point definition utilized in these analysis capabilities, within the SCENIC user interface (UI).

Jasper, Lindsey A.↗
NASA NTRS2018

Analysis of the Planetary Boundary Layer Height During DISCOVER-AQ Baltimore–Washington, D.C., with Lidar and High-Resolution WRF Modeling

The daytime planetary boundary layer (PBL) was examined for the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) Baltimore (Maryland)–Washington, D.C., campaign of July 2011 using PBL height (PBLH) retrievals from aerosol backscatter measurements from ground-based micropulse lidar (MPL), the NASA Langley Research Center airborne High Spectral Resolution Lidar-1 (HSRL-1), and the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. High-resolution Weather Research and Forecasting (WRF) Model simulations with horizontal grid spacing of 1 km and different combinations of PBL schemes, urban parameterization, and sea surface temperature inputs were evaluated against PBLHs derived from lidars, ozonesondes, and radiosondes. MPL and WRF PBLHs depicted a growing PBL in the morning that reached a peak height by midafternoon. WRF PBLHs calculated from gridded output profiles generally showed more rapid growth and higher peak heights than did the MPLs, and all WRF–lidar differences were dependent on model configuration, PBLH calculation method, and synoptic conditions. At inland locations, WRF simulated an earlier descent of the PBL top in the afternoon relative to the MPL retrievals and radiosonde PBLHs. At Edgewood, Maryland, the influence of the Chesapeake Bay breeze on the PBLH was captured by both the ozonesonde and WRF data but generally not by the MPL PBLH retrievals because of generally weaker gradients in the aerosol backscatter profile and limited normalized relative backscatter data near the top height of the marine layer.

Hegarty, Jennifer D.↗
NASA NTRS2015

Methods for LEO Testing of CubeSat Propulsion Systems

Low Earth Orbit is becoming an inexpensive and readily available technology demonstration environment. Many new CubeSat technologies are taking advantage of this as an economical mechanism to advance beyond TRL 5. A wave of CubeSat propulsion systems favoring both reaction control and primary thrust will approach TRL 5 over the coming years, with some already there. These propulsion systems cover a wide range of capabilities including taking CubeSats to interplanetary destinations. In order to determine the feasibility of using LEO to validate the propulsion system performance and in doing so raising the TRL, a variety of factors need to be addressed. These factors include: method of measurement, environmental disturbances, spacecraft control states, and spacecraft mass properties. Propulsion Pathfinder is a NASA Ames Research Center lead project focused on raising the TRL of multiple propulsion systems over a series of flights in the coming years. This paper will highlight a few of the methods of measurement considered by this project to validate the performance of a propulsion system. The measurement methods range from tracking acceleration andor wheel spin-up to monitoring Two Line Elements between thrusting and non thrusting states. Focus will then be placed on the uncertainty of the measurement method and subsequently its feasibility through an analysis of LEO disturbance environment models and common CubeSat mass properties. In addition, the primary spacecraft control states and their imposition from the propulsion system are assessed.

Feasibility↗
NASA NTRS2018

An Artificial Neural Network for Inferring Solar Wind Proxies at Mars

We present a novel method to determine solar wind proxies from sheath measurements at Mars. Specifically, we develop an artificial neural network (ANN) to simultaneously infer seven solar wind proxies: ion density, ion speed, ion temperature, and interplanetary magnetic field magnitude and its vector components, using spacecraft measurements of ion moments, magnetic field magnitude, magnetic field components in the sheath, and the solar extreme ultraviolet flux. The ANN was trained and tested using3 years of data from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. When compared with MAVEN spacecraft's in situ measured values of the solar wind parameters, we find that the ANN proxies for the solar wind ion density, ion speed, ion temperature, and interplanetary magnetic field magnitude havepercentage differences of 50% or less for 84.4%, 99.9%, 86.8%, and 79.8% of the instances, respectively. Forthe cone angle and clock angle proxies, 69.1% and 53.3% of instances, respectively, have angle differences of 30* or less.

Neural Network↗
NASA NTRS2018

Overview of Phobos/Deimos Regolith Ion Sample Mission (PRISM) Concept

Far more definitive information on composition is required to resolve the question of origin for the Martian moons Phobos and Deimos. Current infrared spectra of the objects are inconclusive due to the lack of strong diagnostic features.Definitive compositional measurements of Phobos could be obtained using in-situ X-ray, gamma-ray, or neutronspectroscopy or collecting and returning samples to Earth for analysis. We have proposed, in lieu of those methods, toderive Phobos and Deimos compositional data from secondary ion mass spectrometry (SIMS) measurements by calibratingthe instrument to elemental abundance measurements made for known samples in the laboratory. We describe thePhobos/Deimos Regolith Ion Sample Mission (PRISM) concept here. PRISM utilizes a high-resolution TOF plasma composition analyzer to make SIMS measurements by observing the sputtered species from various locations of the moons' surfaces. In general, the SIMS technique and ion mass spectrometers complement and expand quadrupole mass spectrometer measurements by collecting ions that have been energized to higher energies, 50-100 eV, and making measurements at very low densities and pressures. Furthermore, because the TOF technique accepts all masses all the time,it obtains continuous measurements and does not require stepping through masses. The instrument would draw less than10 W and weigh less than 5 kg. The spacecraft, nominally a radiation-hardened 12U CubeSat, would use a low-thrust SolarElectric Propulsion system to send it on a two-year journey to Mars, where it would co-orbit with Deimos and then Phobos

Clark, Pamela↗
NASA NTRS2019

Evidence for Dry Carbonatite Metasomatism in the Oceanic Lithosphere from Peridotite Xenoliths of Samoa and Lanzarote

Water in Earth’s mantle affects processes like magmatism and plate tectonics. Experiments show that CO2-rich fluids lower the water solubility in olivine, implying that CO2-rich melts/fluids may dehydrate the lithosphere during metasomatism. To test this hypothesis, we report water concentrations (by polarized FTIR) of olivines, orthopyroxenes (OPX) and clinopyroxenes (CPX) from Savai’i (Samoa) and Lanzarote (Canary Islands) peridotite xenoliths with evidence of carbonatite metasomatism. Savai’i peridotites are highly depleted harzburgites and dunites with spinel Cr# (Cr/(Cr+Al)) ranging from 0.4 to 0.76 (estimated degree of melting: 191.5%). Strong Light Rare Earth Element (LREE) enrichments with Ti and Zr depletions in OPX and CO2-rich fluid inclusions (via Raman spectroscopy) are consistent with carbonatite metasomatism. Olivine, OPX and reconstructed bulk rock water concentrations (0.67-3.8, 17-89 and 4-26 ppm H2O, respectively) are low and show no apparent relationship with extent of carbonatite metasomatism. Calculated water concentrations of melts in equilibrium with Savai’i OPX (OPX/melt partitioning of water 0.0063 to 0.011) are, on average (0.540.32 wt% H2O), lower than host Samoan lavas (0.63 to 1.5 wt% H2O), despite the LREE enrichments in OPX. Lanzarote peridotites are also highly depleted (degree of melting from spinel Cr#: 171.8%).Water concentrations are low in olivines (1.7-5.3 ppm H2O) and variable in pyroxenes (OPX: 42-103 ppm H2O; CPX: 105-301 ppm H2O), and show no apparent correlation with indicators of carbonatite metasomatism. Both Savai’i and Lanzarote peridotites show negative correlations between water and degree of melting (i.e. Mg/(Mg+Fe), Cr#), suggesting melt depletion rather than metasomatism may have influenced their water concentrations. Calculated water concentrations of melts in equilibrium with Lanzarote CPX (average 1.90.75 wt% H2O; CPX/melt partitioning of water 0.011 to 0.012) are similar to those for Western Canaries lavas (average 1.80.31 wt%; CPX/melt partitioning of water 0.016 to 0.021) inferred from their CPX phenocrysts. However, calculated Ce concentrations in such melts (352 to 378 ppm; CPX/melt partitioning of Ce 0.07) are an order of magnitude greater than the lavas, and similar to carbonatites. This leads to H2O/Ce to be an order of magnitude lower in the inferred melts (26 to 57) than estimates for Western Canary lavas (280150). These low H2O/Ce ratios may suggest H2O loss from CPX during ascent, but the lack of strong water diffusion gradients in Lanzarote minerals does not support this. Instead we hypothesize that carbonatite metasomatism resulted in greater enrichment of Ce over H2O. Assuming carbonatite magmas are water rich, this implies a lower partitioning of water between minerals and melts during metasomatism, as suggested by experiments. Our data suggests carbonatite metasomatism does not result in significant re-hydration of the lithosphere, in contrast to silicate metasomatism as previously observed in Hawaiian peridotites.

Ashley, Aaron↗
NASA NTRS2018

MAVEN Case Studies of Plasma Dynamics in Low‐Altitude Crustal Magnetic Field at Mars 1: Dayside Ion Spikes Associated With Radial Crustal Magnetic Fields

We report for the first time, simultaneous ion, electron, magnetic field vector and electric field wave measurements made possible by Mars Atmosphere and Volatile EvolutioN, during ion energy flux spikes in low‐altitude radial crustal magnetic fields on the Mars dayside. Observations show energetic electrons and ions (E > 25 eV) precipitating on magnetic field lines assumed as closed. Ions (E < 1.4 keV) display broad velocity distributions toward Mars, showing ions flowing from higher altitude possibly after magnetic reconnection or loss cone filling from pitch angle scattering effects. Precipitating ions (E < 1.4 keV) show nonadiabatic features depending on ion mass and energy and returning ions (E < 1.4 keV) show evidence of conserving the first adiabatic invariant in a mirror field. We observe magnetic field perturbations up to 60 nT, electric field wave amplitudes up to 38 mV/m, and brief periods of peaked electron spectra. At ∼175 km and at times Mars Atmosphere and Volatile EvolutioN is below the mirroring altitude of electrons, we observe mirroring and transverse heating of H+ ions alongside increased electric field wave amplitude fluctuations. It suggests field aligned potential drops result from different mirror altitudes of ions and electrons. Ions E > 1.4 keV (O+) occur as injected accelerated ion beams and ions heated after energization or deceleration. Energy dispersed kilo‐electron‐volt ions suggest a selection effect in radial magnetic fields for lower‐energy Marsward ions, compared to reflection of higher‐energy anti‐Sunward ions. Precipitating kilo‐electron‐volt ions show energy deposition rates of 3.6 ×10(exp -6) W/sq m and sputtering escape rates from precipitating O+ ions of 1.5 ×10(exp 5)/(sq cm.s) and 2.1 ×10(exp 6)/(sq cm.s) are calculated.

Plasma Dynamics↗