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NASA NTRS2013

LVGEMS Time-of-Flight Mass Spectrometry on Satellites

NASA fs investigations of the upper atmosphere and ionosphere require measurements of composition of the neutral air and ions. NASA is able to undertake these observations, but the instruments currently in use have their limitations. NASA has extended the scope of its research in the atmosphere and now requires more measurements covering more of the atmosphere. Out of this need, NASA developed multipoint measurements using miniaturized satellites, also called nanosatellites (e.g., CubeSats), that require a new generation of spectrometers that can fit into a 4 ~4 in. (.10 ~10 cm) cross-section in the upgraded satellites. Overall, the new mass spectrometer required for the new depth of atmospheric research must fulfill a new level of low-voltage/low-power requirements, smaller size, and less risk of magnetic contamination. The Low-Voltage Gated Electrostatic Mass Spectrometer (LVGEMS) was developed to fulfill these requirements. The LVGEMS offers a new spectrometer that eliminates magnetic field issues associated with magnetic sector mass spectrometers, reduces power, and is about 1/10 the size of previous instruments. LVGEMS employs the time of flight (TOF) technique in the GEMS mass spectrometer previously developed. However, like any TOF mass spectrometer, GEMS requires a rectangular waveform of large voltage amplitude, exceeding 100 V -- that means that the voltage applied to one of the GEMS electrodes has to change from 0 to 100 V in a time of only a few nanoseconds. Such electronic speed requires more power than can be provided in a CubeSat. In the LVGEMS, the amplitude of the rectangular waveform is reduced to about 1 V, compatible with digital electronics supplies and requiring little power.

Herrero, Federico↗
NASA NTRS2013

Perspectives on Intracluster Enrichment and the Stellar Initial Mass Function in Elliptical Galaxies

The amount of metals in the Intracluster Medium (ICM) in rich galaxy clusters exceeds that expected based on the observed stellar population by a large factor. We quantify this discrepancy--which we term the "cluster elemental abundance paradox"--and investigate the required properties of the ICM-enriching population. The necessary enhancement in metal enrichment may, in principle, originate in the observed stellar population if a larger fraction of stars in the supernova-progenitor mass range form from an initial mass function (IMF) that is either bottom-light or top-heavy, with the latter in some conflict with observed ICM abundance ratios. Other alternatives that imply more modest revisions to the IMF, mass return and remnant fractions, and primordial fraction, posit an increase in the fraction of 3-8 solar mass stars that explode as SNIa or assume that there are more stars than conventionally thought--although the latter implies a high star formation efficiency. We discuss the feasibility of these various solutions and the implications for the diversity of star formation, the process of elliptical galaxy formation, and the nature of this hidden source of ICM metal enrichment in light of recent evidence of an elliptical galaxy IMF that, because it is skewed to low masses, deepens the paradox.

Lowenstein, Michael↗
NASA NTRS2013

Mass Uncertainty and Application For Space Systems

Expected development maturity under contract (spec) should correlate with Project/Program Approved MGA Depletion Schedule in Mass Properties Control Plan. If specification NTE, MGA is inclusive of Actual MGA (A5 & A6). If specification is not an NTE Actual MGA (e.g. nominal), then MGA values are reduced by A5 values and A5 is representative of remaining uncertainty. Basic Mass = Engineering Estimate based on design and construction principles with NO embedded margin MGA Mass = Basic Mass * assessed % from approved MGA schedule. Predicted Mass = Basic + MGA. Aggregate MGA % = (Aggregate Predicted - Aggregate Basic) /Aggregate Basic.

Beech, Geoffrey↗
NASA NTRS2014

Mass and Volume Optimization of Space Flight Medical Kits

Resource allocation is a critical aspect of space mission planning. All resources, including medical resources, are subject to a number of mission constraints such a maximum mass and volume. However, unlike many resources, there is often limited understanding in how to optimize medical resources for a mission. The Integrated Medical Model (IMM) is a probabilistic model that estimates medical event occurrences and mission outcomes for different mission profiles. IMM simulates outcomes and describes the impact of medical events in terms of lost crew time, medical resource usage, and the potential for medically required evacuation. Previously published work describes an approach that uses the IMM to generate optimized medical kits that maximize benefit to the crew subject to mass and volume constraints. We improve upon the results obtained previously and extend our approach to minimize mass and volume while meeting some benefit threshold. METHODS We frame the medical kit optimization problem as a modified knapsack problem and implement an algorithm utilizing dynamic programming. Using this algorithm, optimized medical kits were generated for 3 mission scenarios with the goal of minimizing the medical kit mass and volume for a specified likelihood of evacuation or Crew Health Index (CHI) threshold. The algorithm was expanded to generate medical kits that maximize likelihood of evacuation or CHI subject to mass and volume constraints. RESULTS AND CONCLUSIONS In maximizing benefit to crew health subject to certain constraints, our algorithm generates medical kits that more closely resemble the unlimited-resource scenario than previous approaches which leverage medical risk information generated by the IMM. Our work here demonstrates that this algorithm provides an efficient and effective means to objectively allocate medical resources for spaceflight missions and provides an effective means of addressing tradeoffs in medical resource allocations and crew mission success parameters.

Monte Carlo Method↗
NASA NTRS2013

Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

climate models↗
NASA NTRS2013

Influence of Persistent Wind Scour on the Surface Mass Balance of Antarctica

Accurate quantification of surface snow accumulation over Antarctica is a key constraint for estimates of the Antarctic mass balance, as well as climatic interpretations of ice-core records. Over Antarctica, near-surface winds accelerate down relatively steep surface slopes, eroding and sublimating the snow. This wind scour results in numerous localized regions (< or = 200 sq km) with reduced surface accumulation. Estimates of Antarctic surface mass balance rely on sparse point measurements or coarse atmospheric models that do not capture these local processes, and overestimate the net mass input in wind-scour zones. Here we combine airborne radar observations of unconformable stratigraphic layers with lidar-derived surface roughness measurements to identify extensive wind-scour zones over Dome A, in the interior of East Antarctica. The scour zones are persistent because they are controlled by bedrock topography. On the basis of our Dome A observations, we develop an empirical model to predict wind-scour zones across the Antarctic continent and find that these zones are predominantly located in East Antarctica. We estimate that approx. 2.7-6.6% of the surface area of Antarctica has persistent negative net accumulation due to wind scour, which suggests that, across the continent, the snow mass input is overestimated by 11-36.5 Gt /yr in present surface-mass-balance calculations.

Antarctica↗
NASA NTRS2014

Black Hole Mass Determination In the X-Ray Binary 4U 1630-47: Scaling of Spectral and Variability Characteristics

We present the results of a comprehensive investigation on the evolution of spectral and timing properties of the Galactic black hole candidate 4U 1630-47 during its spectral transitions. In particular, we show how a scaling of the correlation of the photon index of the Comptonized spectral component gamma with low-frequency quasi-periodic oscillations (QPOs), ν(sub L), and mass accretion rate, M, can be applied to the black hole mass and the inclination angle estimates.We analyze the transition episodes observed with the Rossi X-Ray Timing Explorer and BeppoSAX satellites.We find that the broadband X-ray energy spectra of 4U 1630-47 during all spectral states can be modeled by a combination of a thermal component, a Comptonized component, and a red-skewed iron-line component. We also establish that gamma monotonically increases during transition from the low-hard state to the high-soft state and then saturates for high mass accretion rates. The index saturation levels vary for different transition episodes. Correlations of gamma versus ν(sub L) also show saturation at gamma (is) approximately 3. Gamma -M and gamma -ν(sub L) correlations with their index saturation revealed in 4U 1630-47 are similar to those established in a number of other black hole candidates and can be considered as an observational evidence for the presence of a black hole in these sources. The scaling technique, which relies on XTE J1550-564, GRO 1655-40, and H1743-322 as reference sources, allows us to evaluate a black hole mass in 4U 1630-47 yielding M(sub BH) (is) approximately 10 +/- 0.1 solar masses and to constrain the inclination angle of i (is) approximately less than 70 deg.

accretion↗
NASA NTRS2015

Total Land Water Storage Change over 2003 - 2013 Estimated from a Global Mass Budget Approach

We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of −108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

Water↗
NASA NTRS2015

Low-Mass, Low-Power Hall Thruster System

NASA is developing an electric propulsion system capable of producing 20 mN thrust with input power up to 1,000 W and specific impulse ranging from 1,600 to 3,500 seconds. The key technical challenge is the target mass of 1 kg for the thruster and 2 kg for the power processing unit (PPU). In Phase I, Busek Company, Inc., developed an overall subsystem design for the thruster/cathode, PPU, and xenon feed system. This project demonstrated the feasibility of a low-mass power processing architecture that replaces four of the DC-DC converters of a typical PPU with a single multifunctional converter and a low-mass Hall thruster design employing permanent magnets. In Phase II, the team developed an engineering prototype model of its low-mass BHT-600 Hall thruster system, with the primary focus on the low-mass PPU and thruster. The goal was to develop an electric propulsion thruster with the appropriate specific impulse and propellant throughput to enable radioisotope electric propulsion (REP). This is important because REP offers the benefits of nuclear electric propulsion without the need for an excessively large spacecraft and power system.

Pote, Bruce↗
NASA NTRS2016

Advanced Laser Architecture for Two-Step Laser Tandem Mass Spectrometer

Future astrobiology missions will focus on planets with significant astrochemical or potential astrobiological features, such as small, primitive bodies and the icy moons of the outer planets that may host diverse organic compounds. These missions require advanced instrument techniques to fully and unambiguously characterize the composition of surface and dust materials. Laser desorptionionization mass spectrometry (LDMS) is an emerging instrument technology for in situ mass analysis of non-volatile sample composition. A recent Goddard LDMS advancement is the two-step laser tandem mass spectrometer (L2MS) instrument to address the need for future flight instrumentation to deconvolve complex organic signatures. The L2MS prototype uses a resonance enhanced multi-photon laser ionization mechanism to selectively detect aromatic species from a more complex sample. By neglecting the aliphatic and inorganic mineral signatures in the two-step mass spectrum, the L2MS approach can provide both mass assignments and clues to structural information for an in situ investigation of non-volatile sample composition. In this paper we will describe our development effort on a new laser architecture that is based on the previously flown Lunar Orbiter Laser Altimeter (LOLA) laser transmitter for the L2MS instrument. The laser provides two discrete midinfrared wavelengths (2.8 m and 3.4 m) using monolithic optical parametric oscillators and ultraviolet (UV) wavelength (266 nm) on a single laser bench with a straightforward development path toward flight readiness.

Laser↗
NASA NTRS2016

OGLE-2012-bLG-0950Lb: the First Planet Mass Measurement From Only Microlens Parallax and Lens Flux

We report the discovery of a microlensing planet OGLE-2012-BLG-0950Lb with a planet/host mass ratio Periapsis Approx. = 2 x10(exp. -4). A long term distortion detected in both MOA and OGLE light curve can be explained by themicrolens parallax due to the Earths orbital motion around the Sun. Although the finite source effect is not detected, we obtain the lens flux by the high resolution Keck AO observation. Combining the microlens parallax and the lens flux reveal the nature of the lens: a planet with mass of M(sub p) = 35(+17/-)M compared to Earth is orbiting around an M-dwarf with mass of M(sub host) = 0.56(+0.12/-0.16) M compared to the Sun with a planet-host projected separation of r1 = 2.7(+0.6/-0.7) au located at Luminosity Distance = 3.0(+0.8/-1.1) kpc from us. This is the first mass measurement from only microlens parallax and the lens flux without the finite source effect. In the coming space observation-era with Spitzer, K2, Euclid, and WFIRST, we expect many such events for which we will not be able to measure any finite source effect. This work demonstrates an ability of mass measurements in such events.

microlens parallax↗
NASA NTRS2015

A Chandrasekhar Mass Progenitor for the Type Ia Supernova Remnant 3C 397 from the Enhanced Abundances of Nickel and Manganese

Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios - (0.11-0.24 and 0.018-0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only be achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Together with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.

G41.1-0.3); supernova remnants; nuclear reactions;↗
NASA NTRS2018

The Role of Atmospheric Teleconnections and Local Forcings in Predicting Greenland Ice Sheet Surface Mass Loss

In recent decades, the Arctic climate has experienced substantial climactic change, including significant decreases in both sea ice extent and Greenland Ice Sheet (GrIS) surface mass balance. These trends are overlain by substantial interannual variability in atmospheric circulation driven by large-scale atmospheric teleconnection patterns. In addition, there is evidence to suggest that the removal of Arctic sea ice can alter local atmospheric circulation through increased air temperature, clouds, and water vapor, which may contribute to increased surface melting on the GrIS. Here, we seek to characterize how these processes are linked to Greenland Ice Sheet surface mass loss and constrain how the representation of these forcings can impact the prediction of meltwater runoff within the NASA Goddard Earth Observing System Model (GEOS) seasonal-to-subseasonal forecasting system (S2S v2.1). To do this, we use a combination of the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) reanalysis product, retrospective seasonal forecasts from the GEOS S2S v2.1, and independent GEOS simulations. Results from MERRA-2 reanalysis indicate that the negative phase of the North Atlantic Oscillation (NAO) results in warm surface air temperatures and reduced precipitation across Greenland, both of which act to enhance summer ice surface mass losses. When compared with MERRA-2, retrospective forecasts from the GEOS S2S v2.1 system effectively reproduce the pattern of summer GrIS surface mass loss and demonstrate reasonable skill in predicting the magnitude of meltwater runoff at leads of 1 to 3 months. However, during periods with a strong negative NAO, ice sheet surface mass balance is substantially underestimated. This pattern is also associated with an underprediction of the Greenland Blocking Index height and over prediction of sea ice extent, suggesting that both local and non-local forcings may play a role in the reduced prediction skill during these periods. Using both retrospective forecasts and independent simulations, we characterize the relative importance of local and non-local mechanisms in driving summer GrIS

Andrews, Lauren C.↗
NASA NTRS2018

Using Knowledge Analytics to Search and Characterize Mass Properties Aerospace Data

There is growing capability in the field of “Big Data” and “Data Analytics” which Mass Properties Engineers might like to take advantage of. This paper utilizes an implementation of the IBM Knowledge Analytics and Watson search capabilities to explore a corpus of material developed primarily with the interests of Mass Properties Engineers and vehicle concept developers at its forefront. The full collection of SAWE (Society of Allied Weight Engineers, Inc.) Technical Papers from 1939 through 2015 is a major portion of the knowledge content. Additional aerospace vehicle design information includes metadata from AIAA (American Institute for Aeronautics and Astronautics), and INCOSE (International Council on Systems Engineering) as well as author-provided personal search material. This data is processed with respect to certain expected content, data taxonomies and key words to become the core data in NASA Langley Research Center’s “Vehicle Analysis Analytics”, IBM Watson Content. Processed data becomes the corpus of information which is interrogated to provide examples of finding data for mass regression analysis, technology impacts on MPE (Mass Properties Engineering), mass properties control, standards, and other aspects of interest.

Cerro, Jeffrey A.↗
NASA NTRS2019

MOA-bin-29b: A Microlensing Gas-giant Planet Orbiting a Low-mass Host Star

We report the discovery of a gas-giant planet orbiting a low-mass host star in the microlensing event MOA-bin-29 that occurred in 2006. We find five degenerate solutions with the planet/host-star mass ratio of q ∼ 10(exp−2). The Einstein radius crossing time of all models are relatively short (∼4–7 days), which indicates that the mass of host star is likely low. The measured lens-source proper motion is 5–9 mas/yr depending on the models. Since only finite source effects are detected, we conduct a Bayesian analysis in order to obtain the posterior probability distribution of the lens physical properties. As a result, we find the lens system is likely to be a gas-giant orbiting a brown dwarf or a very late M-dwarf in the Galactic bulge. The probability distributions of the physical parameters for the five degenerate models are consistent within the range of error. By combining these probability distributions, we conclude that the lens system is a gas giant with a mass of M(p)= 0.63(sub +1.13, sub 0.39) M(Jup) orbiting a brown dwarf with a mass of M(h)= 0.06 (sup +0.11, sub -0.04) M(ʘ) at a projected star–planet separation of r⊥ = 0.53(sup +0.89, sub -0.18)au . The lens distance is D(L)= 6.89(sup +1.19, sub -1.19) kpc, i.e., likely within the Galactic bulge.

Iona Kondo↗
NASA NTRS2020

Tidal Disruptions of Main-sequence Stars. IV. Relativistic Effects and Dependence on Black Hole Mass

Using a suite of fully relativistic hydrodynamic simulations applied to main-sequence stars with realistic internal density profiles, we examine full and partial tidal disruptions across a wide range of black hole mass (10(exp 5)≤M(BH)/M(ʘ)≤5 x 10(exp 7) and stellar mass (0.3≤M(*)/M(ʘ)≤3) as larger M(BH) leads to stronger relativistic effects. For fixed M( ), as M(BH) increases, the ratio of the maximum pericenter distance yielding full disruptions ( ) to its Newtonian prediction rises rapidly, becoming triple the Newtonian value for M(BH)=5 x 10(exp 7)M(ʘ), while the ratio of the energy width of the stellar debris for full disruptions to the Newtonian prediction decreases steeply, resulting in a factor of 2 correction at M(BH)=5 x 10(exp 7)M(ʘ). We provide approximate formulae that express the relativistic corrections of both R(t) and the energy width relative to their Newtonian approximate estimates. For partial disruptions, we find that the fractional remnant mass for a given ratio of the pericenter to R(t) is higher for larger M(BH). These results have several implications. As M(BH) increases above ~10(exp 7)M(ʘ), the cross section for complete disruptions is suppressed by competition with direct capture. However, the cross-section ratio for partial to complete disruptions depends only weakly on M(BH). The relativistic correction to the debris energy width delays the time of peak mass-return rate and diminishes the magnitude of the peak return rate. For M(BH)≳10(exp 7)M(ʘ), the M(BH)-dependence of the full disruption cross section and the peak mass-return rate and time is influenced more by relativistic effects than by Newtonian dynamics.

Taeho Ryu↗
NASA NTRS2020

Tidal Disruptions of Main-sequence Stars. IV. Relativistic Effects and Dependence on Black Hole Mass

Using a suite of fully relativistic hydrodynamic simulations applied to main-sequence stars with realistic internal density profiles, we examine full and partial tidal disruptions across a wide range of black hole mass( MM105 105BH7)and stellar mass (MM0.33) as larger MBH leads to stronger relativistic effects. For fixed Må, as MBH increases, the ratio of the maximum pericenter distance yielding full disruptions (t) to its Newtonian prediction rises rapidly, becoming triple the Newtonian value for= ́MM510BH7, while the ratio of the energy width of the stellar debris for full disruptions to the Newtonian prediction decreases steeply, resulting in a factor of 2 correction at= ́MM510BH7. We provide approximate formulae that express the relativistic corrections of both t and the energy width relative to their Newtonian approximate estimates. For partial disruptions, we find that the fractional remnant mass for a given ratio of the pericenter to t is higher for larger MBH. These results have several implications. As MBH increases above~M107, the cross section for complete disruptions is suppressed by competition with direct capture. However, the cross-section ratio for partial to complete disruptions depends only weakly on MBH. The relativistic correction to the debris energy width delays the time of peak mass-return rate and diminishes the magnitude of the peak return rate. ForMM10BH7, the MBH-dependence of the full disruption cross section and the peak mass-return rate and time is influenced more by relativistic effects than by Newtonian dynamics.

Taeho Ryu↗
NASA NTRSDate not supplied

Phase transition energetics-based mass loss modeling of chondritic Near Earth Objects

Mitigating potentially hazardous asteroids relies on accurate knowledge of their composition and critical physical characteristics such as shape and mass. Ground-based observatories and sample return missions in recent years have focused on such characterization to track Near Earth Objects. Historically, entry speeds of asteroids or mass change due to break-up/airburst have been considered in risk assessment studies as critical parameters. To this effect, most hydrocode simulations that consider energy deposition techniques rely on gross meteor modeling with simplistic spherical shapes while neglecting heat of ablation considerations. This is the general approach for fragment-cloud, pancake and hybrid fragmentation models. Alternatively, aerothermal fragmentation modeling that accounts for meteoritic shape change have typically focused on environmental modeling to understand break-up points primarily due to radiative heating. A physics-based risk assessment could benefit by modeling the environment and material response of typical meteoroidal materials as precursors to fragmentation. A greater focus on the material response to applied environmental heating will be emphasized here. This work presents a forward analysis of thermal and material response of stony meteorites by ac-counting for mass loss and shape change effects through a boundary layer formalism. This allows for simulations starting from simplistic shapes that could eventually lead to alterations in contours due to ablation. These effects would be characterized through phase transitions of the surface, such as melting and vaporization, in response to aerodynamic heating. Coupled ablation and radiative heating effects have been found to lead to reduced heat transfer coefficients in the computation of meteor mass loss rates. This has the potential to increase ground damage footprints for hazardous impacts. The effort here quantifies the heat transfer coefficient by accounting for ablation assisted by phase transition. The melt and vaporization mediated ablation of chondritic meteors provides essential recession estimates based upon surface environments. The altered mass due to such phenomena would be presented for a H-chondrite meteoritic sample.

Pratibha Raghunandan↗