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  • Other Sources  (655)
  • Astrophysics  (274)
  • Aerospace Medicine  (203)
  • Fluid Mechanics and Thermodynamics  (178)
  • 2015-2019  (655)
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  • 1
    Publication Date: 2018-11-24
    Description: Prolonged microgravity exposure disrupts natural bone remodeling processes and can lead to a significant loss of bone strength, increasing injury risk during missions and placing astronauts at a greater risk of bone fracture later in life. Resistance based exercise during missions is used to combat bone loss, but current exercise countermeasures do not completely mitigate the effects of microgravity. To address this concern, we present work to develop a personalizable, site-specific computational modeling tool chain of bone remodeling dynamics to understand and estimate changes in volumetric bone mineral density (BMD) in response to microgravityinduced bone unloading and in-flight exercise. The toolchain is evaluated against data collected from subjects in a 70-day bed rest study and is found to provide insight into the amount of exercise stimulus needed to minimize bone loss, quantitatively predicting post-study volumetric BMD of control subjects who did not perform exercise, and qualitatively predicting the effects of exercise. Results suggest that, with additional data, the toolchain could be improved to aid in developing customized in-flight exercise regimens and predict exercise effectiveness.
    Keywords: Aerospace Medicine
    Type: NASA/TM-2018-219938 , E-19552 , GRC-EDAA-TN56704
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  • 2
    Publication Date: 2019-05-30
    Description: We present ALMA 0.87 mm continuum, HCO+ J = 43 emission line, and CO J = 32 emission line data of the disk of material around the young, Sun-like star PDS 70. These data reveal the existence of a possible two-component transitional disk system with a radial dust gap of 0.42 arcsec 0.05 arcsec, an azimuthal gap in the HCO+ J = 43 moment zero map, as well as two bridge-like features in the gas data. Interestingly these features in the gas disk have no analog in the dust disk making them of particular interest. We modeled the dust disk using the Monte Carlo radiative transfer code HOCHUNK3D using a two-disk component. We nd that there is a radial gap that extends from 15 to 60 au in all grain sizes, which differs from previous work.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64788 , Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 858; 2; 112
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  • 3
    Publication Date: 2019-05-09
    Description: Flow visualization is a powerful tool for characterizing fluid dynamics within engineering systems that utilize fluid working media. Recent advances in Positron Emission Tomography (PET) have enhanced its ability to extend beyond the medical field, and offer an alternate vantage point in visualizing optically inaccessible fluid distributions and flow fields within the aerospace field. In light of this prospect an investigation has ensued to parametrically bound the flows that can be sufficiently resolved using current PET technology. Preliminary results from on going simulations and analyses will be presented.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JSC-E-DAA-TN68273
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  • 4
    Publication Date: 2019-06-28
    Description: Large-scale spiral arms have been revealed in scattered light images of a few protoplanetary disks. Theoretical models suggest that such arms may be driven by and corotate with giant planets, which has called for remarkable observational efforts to look for them. By examining the rotation of the spiral arms for the MWC 758 system over a 10 year timescale, we are able to provide dynamical constraints on the locations of their perturbers. We present reprocessed Hubble Space Telescope (HST)/NICMOS F110W observations of the target in 2005, and the new Keck/NIRC2 L'-band observations in 2017. MWC 758's two well-known spiral arms are revealed in the NICMOS archive at the earliest observational epoch. With additional Very Large Telescope (VLT)/SPHERE data, our joint analysis leads to a pattern speed of 0.6(sup +3.3, sub -0.6)/yr at 3 for the two major spiral arms. If the two arms are induced by a perturber on a near-circular orbit, its best-fit orbit is at 89 au (0."59), with a 3 lower limit of 30 au (0."20). This finding is consistent with the simulation prediction of the location of an arm-driving planet for the two major arms in the system.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64824 , The Astrophysica Journal Letters (ISSN 2041-8205) (e-ISSN 2041-8213); 857; 1; L9
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  • 5
    Publication Date: 2019-05-25
    Description: The HST Treasury Program Advanced Spectral Library Project: Cool Stars was designed to collect representative, high-quality UV spectra of eight evolved FM type cool stars. The Space Telescope Imaging Spectrograph (STIS)echelle spectra of these objects enable investigations of a broad range of topics, including stellar and interstellar astrophysics. This paper provides a guide to the spectra of the two evolved M stars, the M2 Iab supergiant Oriand the M3.4 giant Cru, with comparisons to the prototypical K1.5 giant Boo. It includes identifications of the significant atomic and molecular emission and absorption features and discusses the character of the photospheric and chromospheric continua and line spectra. The fluorescent processes responsible for a large portion of the emission-line spectrum, the characteristics of the stellar winds, and the available diagnostics for hot and cool plasmas are also summarized. This analysis will facilitate the future study of the spectra, outer atmospheres, and winds, not only of these objects but of numerous other cool, low-gravity stars, for years to come.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64711 , The Astrophysicial Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 869; 2; 157
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  • 6
    Publication Date: 2019-05-10
    Description: Spaceflight perturbs the human immune system. Among other manifestations, crewmembers may experience latent herpes viruses reactivation due to impaired lymphocyte function, as well as allergic/hypersensitivity reactions. Considering future space travel will be of longer duration (thereby increasing stress, exposure to radiation, etc) with no rapid return option, it is of paramount importance to develop a countermeasure(s) to immune dysregulation. Monophosphoryl lipid A (MPLA) is a derivative of lipopolysaccharide (LPS), a potent inflammatory agent that can cause septic shock. MPLA possesses the immune-stimulatory effects of LPS without the adverse inflammatory effects. We hypothesize that treating immune cells with MPLA will boost their function enough to overcome the inhibitory effects of microgravity. While MPLA has been tested as an adjuvant extensively in mice and preliminarily for human vaccines, it has never been assessed for efficacy in microgravity.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN61280
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  • 7
    Publication Date: 2019-06-28
    Description: Kiefer et al. reported the detection of in falling Ca(sub II) absorption in HD 172555, a member of the Pictoris Moving Group (PMG). We obtained HST Space Telescope Imaging Spectrograph and Cosmic Origins Spectrograph spectroscopy of this star at 2 epochs separated by a week, and we report the discovery of infalling gas in resonant transitions of Si(sub III and IV), C(sub II and IV), and neutral atomic oxygen. Variable absorption is seen in the C(sub II) transitions and is optically thick, with covering factors which range between 58% and 68%, similar to features seen in Pictoris. The O(sub I) spectral profile resembles that of C(sub II), showing a strong low-velocity absorption to +50 km s(exp 1) in the single spectral segment obtained during orbital night, as well as what may be higher-velocity absorption. Studies of the mid-IR spectrum of this system have suggested the presence of silica. The O(sub I) absorption differs from that seen in Si(sub III), suggesting that the neutral atomic oxygen does not originate in SiO dissociation products but in a more volatile parent molecule such as CO.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64812 , The Astrophysical Journal (ISSN 0004-6256) (e-ISSN 1538-3881); 155; 6; 242
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  • 8
    Publication Date: 2019-06-28
    Description: We conducted high-contrast polarimetry observations of T Tau in the H-band, using the High Contrast Instrument for the Subaru Next Generation Adaptive Optics instrument mounted on the Subaru Telescope, revealing structures as near as 0farcs1 from the stars T Tau N and T Tau S. The whole T Tau system is found to be surrounded by nebula-like envelopes, and several outflow-related structures are detected in these envelopes. We analyzed the detailed polarization patterns of the circumstellar structures near each component of this triple young star system and determined constraints on the circumstellar disks and outflow structures. We suggest that the nearly face-on circumstellar disk of T Tau N is no larger than 0".8, or 117 au, in the northwest, based on the existence of a hole in this direction, and no larger than 0".27, or 40 au, in the south. A new structure, "N5," extends to about 0."42, or 59 au, southwest of the star, and is believed to be part of the disk. We suggest that T Tau S is surrounded by a highly inclined circumbinary disk with a radius of about 0."3, or 44 au, with a position angle of about 30, that is misaligned with the orbit of the T Tau S binary. After analyzing the positions and polarization vector patterns of the outflow-related structures, we suggest that T Tau S should trigger the well-known EW outflow, and is also likely to be responsible for a southwest precessing outflow "coil" and a possible south outflow.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64810 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 861; 2; 133
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  • 9
    Publication Date: 2019-05-08
    Description: The low-mass X-ray binary 4U1705-44 exhibits dramatic long-term X-ray time variability with a timescale of several hundred days. The All-Sky Monitor (ASM) aboard the Rossi X-ray Timing Explorer (RXTE) and the Japanese Monitor of All-sky X-ray Image (MAXI) aboard the International Space Station together have continuously observed the source from December 1995 through May 2014. The combined ASM-MAXI data provide a continuous time series over fifty times the length of the timescale of interest. Topological analysis can help us identify fingerprints in the phase-space of a system unique to its equations of motion. The Birman- Williams theorem postulates that if such fingerprints are the same between two systems, then their equations of motion must be closely related. The phase-space embedding of the source light curve shows a strong resemblance to the double-welled nonlinear Duffing oscillator. We explore a range of parameters for which the Duffing oscillator closely mirrors the time evolution of 4U1705-44.We extract low period, unstable periodic orbits from the 4U1705-44 and Duffing time series and compare their topological information. The Duffing and 4U1705- 44 topological properties are identical, providing strong evidence that they share the same underlying template. This suggests that we can look to the Duffing equation to help guide the development of a physical model to describe the long-term X-ray variability of this and other similarly behaved X-ray binary systems.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN55635 , Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711) (e-ISSN 1365-2966); 477; 4; 5220–5237
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  • 10
    Publication Date: 2019-06-28
    Description: Context. The nearby and young M star AU Mic is surrounded by a debris disk in which we previously identified a series of large-scale arch-like structures that have never been seen before in any other debris disk and that move outward at high velocities. Aims. We initiated a monitoring program with the following objectives: (1) track the location of the structures and better constrain their projected speeds, (2) search for new features emerging closer in, and ultimately (3) understand the mechanism responsible for the motion and production of the disk features. Methods. AU Mic was observed at 11 different epochs between August 2014 and October 2017 with the IR camera and spectrograph of SPHERE. These high-contrast imaging data were processed with a variety of angular, spectral, and polarimetric differential imaging techniques to reveal the faintest structures in the disk. We measured the projected separations of the features in a systematic way for all epochs. We also applied the very same measurements to older observations from the Hubble Space Telescope (HST) with the visible cameras STIS and ACS. Results. The main outcomes of this work are (1) the recovery of the five southeastern broad arch-like structures we identified in our first study, and confirmation of their fast motion (projected speed in the range 412 km/s); (2) the confirmation that the very first structures observed in 2004 with ACS are indeed connected to those observed later with STIS and now SPHERE; (3) the discovery of two new very compact structures at the northwest side of the disk (at 0.40 and 0.55 in May 2015) that move to the southeast at low speed; and (4) the identification of a new arch-like structure that might be emerging at the southeast side at about 0.4 from the star (as of May 2016). Conclusions. Although the exquisite sensitivity of SPHERE allows one to follow the evolution not only of the projected separation, but also of the specific morphology of each individual feature, it remains difficult to distinguish between possible dynamical scenarios that may explain the observations. Understanding the exact origin of these features, the way they are generated, and their evolution over time is certainly a significant challenge in the context of planetary system formation around M stars.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64813 , The Astronomy & Astrophysics Journal (ISSN 0004-6361) (e-ISSN 1432-0746); 614; A52
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  • 11
    Publication Date: 2019-05-24
    Description: We present five epochs of near-IR observations of the protoplanetary disk around MWC 480 (HD 31648) obtained with the SpeX spectrograph on NASAs Infrared Telescope Facility between 2007 and 2013, inclusive. Using the measured line fluxes in the Pa and Br lines, we found the mass accretion rates to be (1.262.30) x 10(exp 7) Solar Mass/yr and (1.42.01) x 10(exp 7) Solar Mass/yr, respectively, but which varied by more than 50% from epoch to epoch. The spectral energy distribution reveals a variability of about 30% between 1.5 and 10 m during this same period of time. We investigated the variability using of the continuum emission of the disk in using the Monte- Carlo Radiative Transfer Code HOCHUNK3D. We find that varying the height of the inner rim successfully produces a change in the NIR flux but lowers the far-IR emission to levels below all measured fluxes. Because the star exhibits bipolar flows, we utilized a structure that simulates an inner disk wind to model the variability in the near-IR, without producing flux levels in the far-IR that are inconsistent with existing data. For this object, variable near-IR emission due to such an outflow is more consistent with the data than changing the scale height of the inner rim of the disk.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64790 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 856; 2; 103
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  • 12
    Publication Date: 2019-06-27
    Description: Pairs of azimuthal intensity decrements at near-symmetric locations have been seen in a number of protoplanetary disks. They are most commonly interpreted as the two shadows cast by a highly misaligned inner disk. Direct evidence of such an inner disk, however, remains largely illusive, except in rare cases. In 2012, a pair of such shadows were discovered in scattered-light observations of the near face-on disk around 2MASS J16042165- 2130284, a transitional object with a cavity 60 au in radius. The star itself is a dipper, with quasi-periodic dimming events on its light curve, commonly hypothesized as caused by extinctions by transiting dusty structures in the inner disk. Here, we report the detection of a gas disk inside the cavity using Atacama Large Millimeter/ submillimeter Array (ALMA) observations with 0".2 angular resolution. A twisted butterfly pattern is found in the moment 1 map of the CO (32) emission line toward the center, which is the key signature of a high misalignment between the inner and outer disks. In addition, the counterparts of the shadows are seen in both dust continuum emission and gas emission maps, consistent with these regions being cooler than their surroundings. Our ndings strongly support the hypothesized misaligned inner disk origin of the shadows in the J1604-2130 disk. Finally, the inclination of the inner disk would be close to 45 in contrast with 45; it is possible that its internal asymmetric structures cause the variations on the light curve of the host star.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64797 , The Astrophysical Journal (ISSN 2041-8205) (e-ISSN 2041-8213); 868; 1; L3
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  • 13
    Publication Date: 2019-06-27
    Description: We report an orbital characterization of GJ1108Aab that is a low-mass binary system in the pre-main-sequence phase. Via the combination of astrometry using adaptive optics and radial velocity measurements, an eccentric orbital solution of e = 0.63 is obtained, which might be induced by the KozaiLidov mechanism with a widely separated GJ1108B system. Combined with several observed properties, we conrm that the system is indeed young. Columba is the most probable moving group, to which the GJ1108A system belongs, although its membership to the group has not been established. If the age of Columba is assumed for GJ1108A, the dynamical masses of both GJ1108Aa and GJ1108Ab (M(sub dynamical,GJ1108Aa) = 0.72 0.04 Solar Mass and M(sub dynamical,GJ1108Ab) = 0.30 0.03 Solar Mass) are more massive than what an evolutionary model predicts based on the age and luminosities. We consider that the discrepancy in mass comparison can be attributed to an age uncertainty; the system is likely older than stars in Columba, and effects that are not implemented in classical models such as accretion history and magnetic activity are not preferred to explain the mass discrepancy. We also discuss the performance of the evolutionary model by compiling similar low-mass objects in the evolutionary state based on the literature. Consequently, it is suggested that the current model on average reproduces the mass of resolved low-mass binaries without any signicant offsets.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64800 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 865; 2; 152
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  • 14
    Publication Date: 2019-06-27
    Description: We present SCExAO/CHARIS high-contrast imaging/JHK integral eld spectroscopy of And b, a directly imaged low-mass companion orbiting a nearby B9V star. We detect And b at a high signal-to-noise ratio and extract high-precision spectrophotometry using a new forward-modeling algorithm for (A-)LOCI complementary to KLIP-FM developed by Pueyo et al. And bs spectrum best resembles that of a low-gravity L0L1 dwarf (L0L1). Its spectrum and luminosity are very well matched by 2MASS J0141-4633 and several other 12.515 M(sub J) free-oating members of the 40 Myr old TucHor Association, consistent with a system age derived from recent interferometric results for the primary, a companion mass at/near the deuterium-burning limit (13(sup +12, sub -2) M(sub J)), and a companion-to-primary mass ratio characteristic of other directly imaged planets (q 0.005(sup +0.005, sub -0.001)). We did not unambiguously identify additional, more closely orbiting companions brighter and more massive than And b down to 0".3 (15 au). SCExAO/CHARIS and complementary Keck/NIRC2 astrometric points reveal clockwise orbital motion. Modeling points toward a likely eccentric orbit: a subset of acceptable orbits include those that are aligned with the stars rotation axis. However, And bs semimajor axis is plausibly larger than 55 au and in a region where disk instability could form massive companions. Deeper high-contrast imaging of And and low-resolution spectroscopy from extreme adaptive optics systems such as SCExAO/CHARIS and higher-resolution spectroscopy from Keck/OSIRIS or, later, IRIS on the Thirty Meter Telescope could help to clarify And bs chemistry and whether its spectrum provides an insight into its formation environment.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64795 , The Astrophysical Journal (ISSN 0004-6256) (e-ISSN 1538-3881); 156; 6; 291
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  • 15
    Publication Date: 2019-08-01
    Description: A database of heating and pressure measurements on a 7-deg half-angle cone in a highenthalpy expansion tunnel in CO2 has been generated to support development and validation of computational models to be employed in the design of future Mars missions. Laminar, transitional, and turbulent simulations were performed at the test conditions for comparisons with the data. Close agreement was obtained for both fully-laminar and fully turbulent conditions. For the remaining transitional/turbulent conditions, agreement to within, or slightly more than, the estimated experimental uncertainty was demonstrated. The influence of transition intermittency and transition length models on predicted heating levels was demonstrated, as were differences in turbulent heating predictions generated using various algebraic, one-equation, and two-equation turbulence models. These comparisons provide some measure of confidence in turbulent simulation capabilities; however, because the data were not obtained on a relevant entry vehicle geometry, it is not possible to fully quantify computational uncertainties for the definition of Mars mission aerothermodynamic environments at this time
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NF1676L-29376 , AIAA SciTech Forum: 2018 AIAA Aerospace Sciences Meeting
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  • 16
    Publication Date: 2019-06-22
    Description: To study the azimuthal development of boundary-layer instabilities, a controlled, laser-generated perturbation was created in the freestream of the Boeing/U.S. Air Force Office of Scientific Research Mach 6 Quiet Tunnel. The freestream perturbation convected downstream in the wind tunnel to interact with a flared-cone model. The flared cone is a body of revolution bounded by a circular arc with a 3 m radius. Pressure transducers were used to measure a wave packet generated in the cone boundary layer by the freestream perturbation. Nine of these sensors formed three stations of azimuthal arrays and were used to determine the azimuthal variation of the wave packets in the boundary layer. The freestream laser-generated perturbation was positioned upstream of the model in three different configurations: along the centerline axis, offset from the centerline axis by 1.5 mm, and offset from the centerline axis by 3.0 mm. When the freestream perturbation was offset from the centerline of a flared cone with a 1.0 mm nose radius, a larger wave packet was generated on the side toward which the perturbation was offset. As a result, transition occurred earlier on that side. The offset perturbation did not have as large of an effect on the boundary layer of a nominally sharp flared cone.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NF1676L-27270 , AIAA Journal (ISSN 0001-1452) (e-ISSN 1533-385X); 56; 5; 1867-1877
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  • 17
    Publication Date: 2019-06-12
    Description: The photon-scattering winds of M giants absorb parts of the chromospheric emission lines and produce self-reversed spectral features in high-resolution Hubble Space Telescope (HST)/GHRS spectra. These spectra provide an opportunity to assess fundamental parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the stars mass-loss rate. This paper is the last paper in the series GHRS Observations of Cool, Low-Gravity Stars; the last several have compared empirical measurements of spectral emission lines with models of the winds and mass loss of K giants and supergiants. We have used the Sobolev with Exact Integration radiative transfer code, along with simple models of the outer atmosphere and wind, to determine and compare the wind characteristics of the two M-giant stars, gamma Cru (M3.5III) and mu Gem (M3IIIab), with previously derived values for low-gravity K-stars. The analysis specifies the wind parameters and calculates line profiles for the Mg II resonance lines, in addition to a range of unblended Fe II lines. Our line sample covers a large range of wind opacities and, therefore, probes a range of heights in the atmosphere. Our results show that mu Gem has a slower and more turbulent wind than gamma Cru. Also, mu Gem has a weaker chromosphere, in terms of surface flux, with respect to gamma Cru. This suggests that mu Gem is more evolved than gamma Cru. Comparing the two M giants in this work with previously studied K-giant and supergiant stars (alpha Tau, gamma Dra, and lambda Vel) reveals that the M giants have slower winds than the earlier giants, but exhibit higher mass-loss rates. Our results are interpreted in the context of the winds being driven by Alfvn waves.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN68825 , GSFC-E-DAA-TN64696 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 869; 1; 1
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  • 18
    Publication Date: 2019-06-11
    Description: The HST (Hubble Space Telescope) Treasury Program Advanced Spectral Library Project: Cool Stars was designed to collect representative, high-quality ultraviolet spectra of eight evolved F-M type cool stars. The Space Telescope Imaging Spectrograph (STIS) echelle spectra of these objects enable investigations of a broad range of topics, including stellar and interstellar astrophysics. This paper provides a guide to the spectra of the two evolved M stars, the M2 Iab super giant alpha Ori and the M3.4 giant gamma Cru, with comparisons to the prototypical K1.5 giant alpha Boo. It includes identifications of the significant atomic and molecular emission and absorption features and discusses the character of the photospheric and chromospheric continua and line spectra. The fluorescent processes responsible for a large portion of the emission-line spectrum, the characteristics of the stellar winds, and the available diagnostics for hot and cool plasmas are also summarized. This analysis will facilitate the future study of the spectra, outer atmospheres, and winds, not only of these objects but of numerous other cool, low-gravity stars, for years to come.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN68820 , The Astrophysical Journal (ISSN 2041-8205) (e-ISSN 2041-8213); 869; 2; 157
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  • 19
    Publication Date: 2019-06-11
    Description: The Hunt for Observable Signatures of Terrestrial Systems survey searches for dust near the habitable zones (HZs) around nearby, bright main-sequence stars. We use nulling interferometry in the N band to suppress the bright stellar light and to probe for low levels of HZ dust around the 30 stars observed so far. Our overall detection rate is 18%, including four new detections, among which are the first three around Sun-like stars and the first two around stars without any previously known circumstellar dust. The inferred occurrence rates are comparable for early-type and Sun-like stars, but decrease from 60(sup +16)(sub -21)% for stars with previously detected cold dust to 8(sup +10)(sub -3)% for stars without such excess, confirming earlier results at higher sensitivity. For completed observations on individual stars, our sensitivity is five to ten times better than previous results. Assuming a lognormal excess luminosity function, we put upper limits on the median HZ dust level of 13 zodis (95% confidence) for a sample of stars without cold dust and of 26 zodis when focusing on Sun-like stars without cold dust. However, our data suggest that a more complex luminosity function may be more appropriate. For stars without detectable Large Binocular Telescope Interferometer (LBTI) excess, our upper limits are almost reduced by a factor of two, demonstrating the strength of LBTI target vetting for future exo-Earth imaging missions. Our statistics are limited so far, and extending the survey is critical to informing the design of future exo-Earth imaging surveys.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64720 , Astronomical Journal (ISSN 0004-6256) (e-ISSN 1538-3881); 155; 5; 194
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  • 20
    Publication Date: 2019-07-20
    Description: The biomechanics of exercise in space is difficult to study and there are unknowns surrounding exercise performance on future space exploration countermeasures systems. These issues are beginning to be addressed through enhanced modeling techniques fueled initially by human-in-the-loop data collections in ground-based environments. The presentation will focus on an effort completed at the University of South Florida to apply the Computer Assisted Rehabilitation Environment (CAREN) system to address a human spaceflight need. The research explored the interaction between a human and a moving platform while exercise was completed.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN64321
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  • 21
    Publication Date: 2019-07-20
    Description: While astronauts are returning from long duration spaceflight with multiple ocular signs that mimic those seen in terrestrial patients with elevated intracranial pressure (ICP), evidence has yet to prove a clinically significant increase in ICP during space.1 Preliminary research evidence may even suggest that ICP decreases in microgravity. Idiopathic intracranial hypertension (IIH) has long been considered the ideal terrestrial analogue to Spaceflight Associated Neuro-ocular Syndrome (SANS).1 However, there are several critical features of SANS that do not complement any reported case of IIH on Earth. These findings mandate a closer look at the accuracy of IIH as a terrestrial SANS analog.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN51874 , NASA Human Research Program Investigators Workshop; Jan 22, 2018; Galveston, TX; United States
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  • 22
    Publication Date: 2019-06-27
    Description: Context. Debris disks are the intrinsic by-products of the star and planet formation processes. Most likely due to instrumental limitations and their natural faintness, little is known about debris disks around low mass stars, especially when it comes to spatially resolved observations. Aims. We present new VLT/SPHERE IRDIS dual-polarization imaging (DPI) observations in which we detect the dust ring around the M2 spectral type star TWA 7. Combined with additional angular differential imaging observations we aim at a fine characterization of the debris disk and setting constraints on the presence of low-mass planets. Methods. We modeled the SPHERE DPI observations and constrain the location of the small dust grains, as well as the spectral energy distribution of the debris disk, using the results inferred from the observations, and performed simple N-body simulations. Results. We find that the dust density distribution peaks at ~0.72 (25 au), with a very shallow outer power-law slope, and that the disk has an inclination of ~13 with a position angle of ~91 east of north. We also report low signal-to-noise ratio detections of an outer belt at a distance of ~1.5 (~52 au) from the star, of a spiral arm in the southern side of the star, and of a possible dusty clump at 0.11. These findings seem to persist over timescales of at least a year. Using the intensity images, we do not detect any planets in the close vicinity of the star, but the sensitivity reaches Jovian planet mass upper limits. We find that the SED is best reproduced with an inner disk at ~0.2 (~7 au) and another belt at 0.72 (25 au). Conclusions. We report the detections of several unexpected features in the disk around TWA 7. A yet undetected 100 Solar Mass planet with a semi-major axis at 2030 au could possibly explain the outer belt as well as the spiral arm. We conclude that stellar winds are unlikely to be responsible for the spiral arm.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64806 , Astronomy & Astrophysics (ISSN 0004-6361) (e-ISSN 1432-0746); 617; A109
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  • 23
    Publication Date: 2019-06-27
    Description: We present H- and K s-bands observations of the LkH 330 disk with a multi-band detection of the large gap and spiral-like structures. The morphology of the outer disk (r ~ 0."3) at PA = 045 and PA = 180290 is likely density wave-induced spirals, and comparison between our observational results and simulations suggests a planet formation. We have also investigated the azimuthal profiles at the ring and the outer-disk regions as well as radial profiles in the directions of the spiral-like structures and semimajor axis. Azimuthal analysis shows a large variety in wavelength and implies that the disk has non-axisymmetric dust distributions. The radial profiles in the major-axis direction (PA = 271) suggest that the outer region (r 0."25) may be influenced by shadows of the inner region of the disk. The spiral-like directions (PA = 10 and 230) show different radial profiles, which suggests that the surfaces of the spiral-like structures are highly flared and/or have different dust properties. Finally, a color map of the disk shows a lack of an outer eastern region in the H-band disk, which may hint at the presence of an inner object that casts a directional shadow onto the disk.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64807 , The Astrophysical Journal (ISSN 0004-6256) (e-ISSN 1538-3881); 156; 2; 63
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  • 24
    Publication Date: 2019-06-27
    Description: We present new, near-infrared (1.12.4 m) high-contrast imaging of the bright debris disk surrounding HIP 79977 with the Subaru Coronagraphic Extreme Adaptive Optics system (SCExAO) coupled with the CHARIS integral eld spectrograph. SCExAO/CHARIS resolves the disk down to smaller angular separations of (0".11; r 14 au) and at a higher signicance than previously achieved at the same wavelengths. The disk exhibits a marginally signicant eastwest brightness asymmetry in H band that requires conrmation. Geometrical modeling suggests a nearly edge-on disk viewed at a position angle of 114.6 east of north. The disk is best-t by scattered-light models assuming strongly forward-scattering grains (g 0.50.65) conned to a torus with a peak density at r0 5375 au. We nd that a shallow outer density power law of (sub out) = 1 to 3 and are index of = 1 are preferred. Other disk parameters (e.g., inner density power law and vertical scale height) are more poorly constrained. The disk has a slightly blue intrinsic color and its prole is broadly consistent with predictions from birth ring models applied to other debris disks. While HIP 79977s disk appears to be more strongly forward- scattering than most resolved disks surrounding 530 Myr old stars, this difference may be due to observational biases favoring forward-scattering models for inclined disks versus lower inclination, ostensibly neutral-scattering disks like HR 4796As. Deeper, higher signal-to-noise SCExAO/CHARIS data can better constrain the disks dust composition.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64796 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 156; 6; 279
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  • 25
    Publication Date: 2019-07-19
    Description: Vision changes identified in long duration spaceflight astronauts has led Space Medicine at NASA to adopt a more comprehensive clinical monitoring protocol. Optical Coherence Tomography (OCT) was recently implemented at NASA, including on board the International Space Station in 2013. NASA is collaborating with Heidelberg Engineering to increase the fidelity of the current OCT data set by integrating the traditional circumpapillary OCT image with radial and horizontal block images at the optic nerve head. The retinal nerve fiber layer was segmented by two experienced individuals. Intra-rater (N=4 subjects and 70 images) and inter-rater (N=4 subjects and 221 images) agreement was performed. The results of this analysis and the potential benefits will be presented.
    Keywords: Aerospace Medicine
    Type: JSC-CN-40550 , NASA Human Research Program Investigators'' Workshop (HRP IWS 2018); Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 26
    Publication Date: 2019-07-19
    Description: The purpose of this pilot study is to investigate the collection, preparation, and analysis of tear biomarkers as a means of assessing ocular, neurological, and immunological health. At present, no published data exists on the cytokine profiles of tears from astronauts exposed to long periods of microgravity and space irradiations. In addition, no published data exist on cytokine (biomarker) profiles of tears that have been collected from irradiated non-human biological systems (primates and other animal models). A goal for the proposed pilot study is to discover novel tear biomarkers which can help inform researchers, clinicians, epidemiologist and healthcare providers about the health status of a living biological system, as well as informing them when a disease state is triggered. This would be done via analysis of the onset of expression of pro-inflammatory cytokines, leading up to the full progression of a disease (i.e. cancer, loss of vision, radiation-induced oxidative stress, cardiovascular disorders, fibrosis in major organs, bone loss). Another goal of this pilot study is to investigate the state of disease against proposed medical countermeasures, in order to determine whether the countermeasures are efficacious in preventing or mitigating these injuries. An example of an up and coming tear biomarker technology, Ascendant Dx, a clinical stage diagnostic company, is developing a screening test to detect breast cancer using proteins from tears. The team utilized Liquid Chromatography -Mass Spectrometry with Mass analysis (LC MS/MS) as a discovery platform followed by validation with ELISA to come up with a panel of protein biomarkers that can differentiate breast cancer samples from control ("cancer free") samples with results far surpassing the results of imaging techniques in use today. Continued research into additional proteins is underway to increase the sensitivity and specificity of the test and development efforts are on the way to transfer the test onto a fast, accurate and inexpensive point of care platform. In conclusion, the expected results from this proposed pilot study are to: a) establish an SOP for retrieving/storing/transporting tear fluid samples from multicentre sites b) establish a normal range for relevant biomarkers in tears; and c) establish a database (biobank) of tears of space nave versus veteran astronauts, to establish a personal baseline for long-term ocular health monitoring
    Keywords: Aerospace Medicine
    Type: JSC-CN-40616 , 2018 NASA Human Research Program Investigators'' Workshop (HRP IWS); Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 27
    Publication Date: 2019-07-19
    Description: The International Space Station Medical Projects (ISSMP) Element provides planning, integration, and implementation services for HRP research studies for both spaceflight and flight analog research. Through the implementation of these two efforts, ISSMP offers an innovative way of guiding research decisions to meet the unique challenges of understanding the human risks to space exploration. Flight services provided by ISSMP include leading informed consent briefings, developing and validating in-flight crew procedures, providing ISS crew and ground-controller training, real-time experiment monitoring, on-orbit experiment and hardware operations and facilitating data transfer to investigators. For analog studies at the NASA Human Exploration Research Analog (HERA), the ISSMP team provides subject recruitment and screening, science requirements integration, data collection schedules, data sharing agreements, mission scenarios and facilities to support investigators. The ISSMP also serves as the HRP interface to external analog providers including the :envihab bed rest facility (Cologne, Germany), NEK isolation chamber (Moscow, Russia) and the Antarctica research stations. Investigators working in either spaceflight or analog environments requires a coordinated effort between NASA and the investigators. The interdisciplinary nature of both flight and analog research requires investigators to be aware of concurrent research studies and take into account potential confounding factors that may impact their research objectives. Investigators must define clear research requirements, participate in Investigator Working Group meetings, obtain human use approvals, and provide study-specific training, sample and data collection and procedures all while adhering to schedule deadlines. These science requirements define the technical, functional and performance operations to meet the research objectives. The ISSMP maintains an expert team of professionals with the knowledge and experience to guide investigators science through all aspects of mission planning, crew operations, and research integration. During this session, the ISSMP team will discuss best-practices approaches for successfully preparing and conducting studies in both the flight and analog environments. Critical tips and tricks will be shown to greatly improve your chances of successfully completing your research aboard the International Space Station and in Spaceflight Analogs.
    Keywords: Aerospace Medicine
    Type: JSC-CN-40648 , 2018 NASA Human Research Program Investigators'' Workshop (HRP IWS 2018); Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 28
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    In:  CASI
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN63735 , McGovern Medical School Presentation; Dec 10, 2018; Houston, Tx; United States
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  • 29
    Publication Date: 2019-07-19
    Description: Microgravity inflicts substantial, but undercharacterized, pressure on organisms that induces metabolic responses such as increased microbial virulence and antibiotic resistance, altered organ weights in developing rats, and loss of bone tissue in astronauts. Numerous studies have analyzed the effects of microgravity on specific organisms, tissues, or test conditions, but these projects are necessarily limited by the small sample size of space research. Increasing the sample size of spaceflight studies is non-trivial; however, pooling data from numerous studies can greatly increase the statistical rigor of comparative analyses. The GeneLab houses datasets from 73 spaceflight studies that performed transcription profiling assays. These data encompass a diverse array of organisms ranging from Escherichia coli to Mus musculus to Homo sapiens and comprise studies analyzing ionizing radiation, mammalian pregnancy, etc. Collectively, the GeneLab database contains a large quantity of transcription assays and RNA sequence data analyzing Differential Gene Expression (DGE) between microand normogravity. Xspecies, a cross-species analysis method for DGE developed by Kristiansson, et al. in 2012, identifies homologous genes between species that are universally up- or downregulated in response to test conditions. Previous work by an intern at GeneLab applied Xspecies to 19 datasets containing seven different species and identified 14 homologous groups differentially expressed under spaceflight conditions including several heat shock proteins and cytoskeletal components. Unfortunately, these results may be biased by the disproportionate number of studies on Arabidopsis thaliana (5) and Mus musculus (6) and the results are not normalized by evolutionary distances. Here, we present modifications to the Xspecies algorithm that permits incorporation of multi-omic data and normalizes data for effect size, directionality, and evolutionary distances. We then apply this algorithm to all currently available GeneLab studies
    Keywords: Aerospace Medicine
    Type: ARC-E-DAA-TN57976 , American Society for Gravitational and Space Research (ASGSR) Meeting 2018; Oct 31, 2018 - Nov 03, 2018; Washington, DC; United States
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  • 30
    Publication Date: 2019-07-20
    Description: A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable smart therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.
    Keywords: Aerospace Medicine
    Type: ARC-E-DAA-TN62901 , Senior Technical Meeting: Bio Materials in Applied Chemistry; Nov 10, 2018 - Nov 11, 2018; Guayanilla, Puerto Rico; United States
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  • 31
    Publication Date: 2019-07-20
    Description: The calorimeter array of the JAXA Astro-H (renamed Hitomi) soft x-ray spectrometer (SXS) was designed to provide unprecedented spectral resolution of spatially extended cosmic x-ray sources and of all cosmic x-ray sources in the Fe-K band around 6 keV. The properties that made the SXS array a powerful x-ray spectrometer also made it sensitive to photons from the entire electromagnetic band as well as particles. If characterized as a bolometer, it would have had a noise equivalent power of 〈4 10(exp 18) W/((Hz)(exp 0.5)). Thus, it was imperative to shield the detector from thermal radiation from the instrument and optical and UV photons from the sky. In addition, it was necessary to shield the coldest stages of the instrument from the thermal radiation emanating from the warmer stages. These needs were addressed by a series of five thin-film radiation-blocking filters, anchored to the nested temperature stages, that blocked long-wavelength radiation while minimizing x-ray attenuation. The aperture assembly was a system of barriers, baffles, filter carriers, and filter mounts that supported the filters and inhibited their potential contamination. The three outer filters also had been equipped with thermometers and heaters for decontamination. We present the requirements, design, implementation, and performance of the SXS aperture assembly and blocking filters.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66167 , Journal Astronomical Telescopes, Instruments, and Systems; 4; 1; 011215
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  • 32
    Publication Date: 2019-07-20
    Description: X-ray astronomy critically depends on X-ray optics. The capability of an X-ray telescope is largelydetermined by the point-spread function (PSF) and the photon-collection area of its mirrors, the same astelescopes in other wavelength bands. Since an X-ray telescope must be operated above the atmosphere inspace and that X-rays reflect only at grazing incidence, X-ray mirrors must be both lightweight and thin, bothof which add significant technical and engineering challenge to making an X-ray telescope. In this paper wereport our effort at NASA Goddard Space Flight Center (GSFC) of developing an approach to making an Xraymirror assembly that can be significantly better than the mirror assembly currently flying on the ChandraX-ray Observatory in each of the three aspects: PSF, effective area per unit mass, and production cost per uniteffective area. Our approach is based on the precision polishing of mono-crystalline silicon to fabricate thinand lightweight X-ray mirrors of the highest figure quality and micro-roughness, therefore, having thepotential of achieving diffraction-limited X-ray optics. When successfully developed, this approach will makeimplementable in the 2020s and 2030s many X-ray astronomical missions that are currently on the drawingboard, including sounding rocket flights such as OGRE, Explorer class missions such as STAR-X andFORCE, Probe class missions such as AXIS, TAP, and HEX-P, as well as large missions such as Lynx.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66158 , Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray; 10699; 106990O|SPIE Astronomical Telescopes + Instrumentation, 2018,; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 33
    Publication Date: 2019-07-20
    Description: Researchers at NASA Ames in California have built a new facility that uses multiple 50-kW continuous wave lasers to add the capability for simulating radiative heating on thermal protection materials. The new facility, the Laser Enhanced Arc-jet Facility (LEAF-Lite), was added to NASA Amess Interaction Heating Facility arc-jet and now allows for test articles to be heated by both convective and radiative heat flux, making the facility more like flight. Using this new system, researchers can now simulate radiant heating with the laser and convective heating with the arc-jet simultaneously on a single test article. During its initial test in October 2017, the lasers radiatively heated a 6 x 6 Avcoat wedge sample to 405 W/sq.cm while the arc-jet simultaneously provided 160 W/sq.cm of convective heat, resulting in a total heat flux of 565 W/sq.cm. Radiative heating is more prevalent in missions with higher atmospheric entry speeds like the Orion space capsule or interplanetary scientific probes. Later this year, scientists will expand the spot size to cover 17 x 17 to test an Orion TPS panel.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN60998
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  • 34
    Publication Date: 2019-07-19
    Description: Moon Burst Energetics All-sky Monitor (MoonBEAM) is a CubeSat concept of deploying gamma-ray detectors in cislunar space to increase gamma-ray burst detections and improve localization precision with the timing triangulation technique. A gamma-ray instrument in cislunar orbit will have greatly reduced sky blockage compared to instruments in low Earth orbit. Working in conjunction with another instrument in low Earth orbit, MoonBEAM can also help constrain the arrival direction of the wavefront to an annulus on the sky by utilizing the light arrival times between the different orbits. This method has been demonstrated by the Interplanetary Gamma- Ray Burst Timing Network. However, delays in data downlink for instruments outside the Tracking and Data Relay Satellite network prevent rapid follow-up observations. We present here a gamma-ray CubeSat concept in Earth-Moon L3 halo orbit that is capable of faster response and provide a timing baseline for localization improvement. Such an instrument would aid in the gravitational wave follow-up observations in other wavelengths to identify the gamma-ray burst afterglow and kilonova emission. Reducing the region of interest makes identifying afterglows much faster, allowing for rapid on-source observations and monitoring of the rise and decay times. It will also prevent source confusion between two transients and enable robust association. A gamma-ray detection could also increase the confidence of a simultaneous but marginal gravitational wave signal, extending the detection horizon. MoonBEAM is a 12U CubeSat concept of deploying gamma-ray detectors in cislunar space to increase gamma-ray burst detections and improve localization precision with the timing triangulation technique. Such an instrument would probe the extreme processes in cosmic collision of compact objects and facilitate multi-messenger time-domain astronomy to explore the end of stellar life cycles and black hole formations.
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN60786 , International Fermi Symposium; Oct 14, 2018 - Oct 19, 2018; Baltimore, MD; United States
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  • 35
    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: ARC-E-DAA-TN53304/SUPPL
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  • 36
    Publication Date: 2019-07-12
    Description: The risk of developing radiation-induced lung cancer differs between different strains of mice, but the underlying cause of the strain differences is unknown. Strains of mice also differ in their ability to efficiently repair DNA double strand breaks resulting from radiation exposure. We phenotyped mouse strains from the CcS/Dem recombinant congenic strain set for their efficacy in repairing DNA double strand breaks during protracted radiation exposures. We monitored persistent gamma-H2AX radiation induced foci (RIF) 24 hours after exposure to chronic gamma-rays as a surrogate marker for repair deficiency in bronchial epithelial cells for 17 of the CcS/Dem strains and the BALB/cHeN founder strain. We observed a very strong correlation R2 = 79.18%, P 〈 0.001) between the level of persistent RIF and radiogenic lung cancer percent incidence measured in the same strains. Interestingly, spontaneous levels of foci in non-irradiated strains also showed good correlation with lung cancer incidence (R2=32.74%, P =0.013). These results suggest that genetic differences in DNA repair capacity largely account for differing susceptibilities to radiation-induced lung cancer among CcS/Dem mouse strains and that high levels of spontaneous DNA damage is also a relatively good marker of cancer predisposition. In a smaller pilot study, we found that the repair capacity measured in peripheral blood leucocytes also correlated well with radiogenic lung cancer susceptibility, raising the possibility that such phenotyping assay could be used to detect radiogenic lung cancer susceptibility in humans.
    Keywords: Aerospace Medicine
    Type: ARC-E-DAA-TN53304
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  • 37
    Publication Date: 2019-07-12
    Description: The near and very near wake of a thin flat plate with a circular trailing edge are investigated with direct numerical simulations (DNS). Data obtained for two different Reynolds numbers (based on plate thickness, D) are the main focus of this study. The separating boundary layers are turbulent in both cases. An earlier investigation of one of the cases (Case F) showed shed vortices in the wake that were about 1.0 D to 4.0 D in spanwise length. Considerable variation in both the strength and frequency of these shed vortices was observed. One objective of the present investigation is to determine the important contributors to this variability in strength and frequency of shed vortices and their finite spanwise extent. Analysis of the data shows that streamwise vortices in the separating boundary layer play an important role in strengthening/weakening of the shed vortices and that high/low-speed streaks in the boundary layer are important contributors to variability in shedding frequency. Both these features of the boundary layer contribute to the finite extent of the vortices in the spanwise direction. The second plate DNS (Case G, with 40 percent of the plate thickness of Case F) shows that while shedding intensity is weaker than obtained in Case F, many of the wake features are similar to that of Case F. This is important in understanding the path to the wake of the thin plate with a sharp trailing edge where shedding is absent. Here we also test the efficacy of a functional relationship between the shedding frequency and the Reynolds numbers based on the boundary layer momentum thickness (Re (sub theta) and D (Re (sub D)); data for developing this behavioral model is from Cases F & G and five earlier DNSs of the flat plate wake.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA/TM-2018-219752 , ARC-E-DAA-TN52073
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  • 38
    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN59272
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  • 39
    Publication Date: 2019-07-12
    Description: The AMO (Autonomous Medical Operations) Project is working extensively to train medical models on the reliability and confidence of computer-aided interpretation of ultrasound images in various clinical settings, and of various anatomical structures. AI (Artificial Intelligence) algorithms recognize and classify features in the ultrasound images, and these are compared to those features that clinicians use to diagnose diseases. The acquisition of clinically validated image assessment and the use of the AI algorithms constitutes fundamental baseline for a Medical Decision Support System that will advise crew on long-duration, remote missions.
    Keywords: Aerospace Medicine
    Type: NASA-FS-2018-04-01-ARC , ARC-E-DAA-TN54219
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  • 40
    Publication Date: 2019-07-12
    Description: Head-up tilt (HUT) tests often are used in research to measure orthostatic intolerance (OI) (inability to appropriately control blood pressure while upright) in clinical populations and otherwise healthy individuals after interventions. Post-space flight orthostatic intolerance is a well-known phenomenon, and countermeasures to its development has been an active area of research at NASA. In the NASA HUT protocol, subjects lie horizontally on an automatic tilt table for baseline measurements before being raised to 80deg head-up tilt for a defined period of time or until signs or symptoms of presyncope ensues (light-headedness, nausea, dizziness, sweating, weakness or fainting). Multiple measures are collected to evaluate the cardiovascular system's ability to respond appropriately to the orthostatic challenge. However if the intended duration of the HUT is short, the ability to detect changes in OI due to an intervention or its prevention by a countermeasure may be limited by a small number of failures to permit comparisons based on survival time alone. Thus, the time-trajectory of the cardiovascular data becomes an important additional source of information. In particular, we will show how various measures of trajectory variability can effectively augment survival analysis for the assessment of OI in a joint model when high censoring rates are present.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN51782
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  • 41
    Publication Date: 2019-07-12
    Description: Time-resolved observations of brown dwarfs' rotational modulations provide powerful insights into the properties of condensate clouds in ultra-cool atmospheres. Multi-wavelength light curves reveal cloud vertical structures, condensate particle sizes, and cloud morphology, which directly constrain condensate cloud and atmospheric circulation models. We report results from Hubble Space Telescope/Wide Field Camera 3 (WFC3) near-infrared G141 taken in six consecutive orbits observations of HNPeg B, an L/T transition brown dwarf companion to a G0V type star. The best-fit sine wave to the 1.1 to 1.7 micron broadband light curve has the amplitude of and period of hour. The modulation amplitude has no detectable wavelength dependence except in the 1.4 micron water absorption band, indicating that the characteristic condensate particle sizes are large (greater than 1 micron). We detect significantly (4.4 sigma) lower modulation amplitude in the 1.4 micron water absorption band, and find that HN Peg B's spectral modulation resembles those of early T type brown dwarfs. We also describe a new empirical interpolation method to remove spectral contamination from the bright host star. This method may be applied in other high-contrast time-resolved observations with WFC3.
    Keywords: Astrophysics
    Type: ARC-E-DAA-TN52248
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  • 42
    Publication Date: 2019-07-20
    Description: To experimentally assess and compare the mixing performance of high-speed fuel injectors for scramjet engines, quantitative global metrics are needed. The one-dimensional metric most commonly used to assess the degree of mixing completeness at a given downstream station is the mixing efficiency parameter. The experimental determination of the mixing efficiency parameter requires measurement of the spatial distributions of both the fuel mass fraction and the mass flux. Standard in-stream gas sampling techniques can be used to measure the fuel mass fraction distribution, however the mass flux distribution is not easily determined experimentally because it requires the measurement of three independent aerothermodynamic variables in addition to the mixture composition. For this reason, several metrics that can be calculated from the fuel distribution alone are commonly used to assess mixing performance. Because these other metrics do not provide a mass flux-weighted measure of the local degree of mixing completeness, they may not correlate well with the mixing efficiency parameter. Therefore, if the substitute metrics are to be used to compare the mixing performance of candidate fuel injector concepts, it is important to understand their relationships to the mixing efficiency parameter in a representative scramjet combustor flowfield. This work investigates the relationships between the mixing efficiency parameter and several substitute metrics that are able to be measured with the current experimental setup of the Enhanced Injection and Mixing Project at the NASA Langley Research Center for baseline strut and ramp injectors. The results of these comparisons have revealed that it is possible to glean different (i.e., incorrect) conclusions about which injector is the better mixer when the substitute mixing performance metrics are used instead of the mixing efficiency parameter, thereby highlighting the importance of mass flux-weighted mixing performance metrics.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NF1676L-29283 , AIAA Space and Astronautics Forum; Sep 17, 2018 - Sep 19, 2018; Orlando, FL; United States
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  • 43
    Publication Date: 2019-07-20
    Description: This work presents a detailed current performance analysis for the telescope, pointing, and coronagraph com- ponent subsystems of the Segmented Aperture Interferometric Nulling Testbed (SAINT). The project pairs an active segmented mirror with the Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatories needed to directly detect and characterize Earth-sized worlds around nearby stars. We describe approaches to optimize subsystem wavefront sensing and control parameters, summarizing relevant scal- ing relations between these parameters, residual errors, and observed contrast measurements. Preliminary results from diagnostic testing under various control states are presented along with intermediate contrast measurements towards demonstrating the full system.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66135 , SPIE Astronomical Telescopes + Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 44
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN62873 , Applied Superconductivity Conference; Oct 28, 2018 - Nov 02, 2018; Seattle, WA; United States
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  • 45
    Publication Date: 2019-07-20
    Description: We have successfully flown the EcAMSat (Escherichia coli Antimicrobial Satellite) free-flyer mission. This was a 6U small satellite that autonomously conducted an experiment in low Earth orbit to explore the impact of the space environment on antibiotic resistance in uropathogenic E. coli (UPEC) and the role a particular sigma factor plays in the response. After being held in stasis during transport to orbit, two strains a wildtype UPEC and an isogenic mutant with a deleted gene that encodes a sigma factor were grown to stationary phase in a fluidic card inside EcAMSat's payload, then incubated with three concentrations of the antibiotic gentamicin. The payload then administered alamarBlue, a redox indicator, into all wells of the fluidic card. The cells were then incubated for 144 hours and metabolic activity was measured optically using the payloads' LED and detector system. Data were then telemetered to the ground and compared to a control experiment conducted in an identical satellite in a lab. The results of this experiment will help us better understand important therapeutic targets for treating bacterial infections on Earth and in space. Such targets are particularly relevant to deep-space and long-duration missions where crew may be more susceptible to infection and treatments for them may work differently.
    Keywords: Aerospace Medicine
    Type: ARC-E-DAA-TN62656 , American Society for Gravitational and Space Research (ASGSR); Oct 31, 2018 - Nov 03, 2018; Bethesda, MD; United States
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  • 46
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    Unknown
    In:  CASI
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN61165 , UCSD Co-Investigator Workshop; Jan 25, 2018 - Jan 26, 2018; Houston, Tx; United States
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  • 47
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN60996
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  • 48
    Publication Date: 2019-07-20
    Description: The objective of the Heatshield for Extreme Entry Environment Technology (HEEET) projects is to mature a 3-D Woven Thermal Protection System (TPS) to Technical Readiness Level (TRL) 6 to support future NASA missions to destinations such as Venus and Saturn. Destinations that have extreme entry environments with heat fluxes up to 5000 watts per square centimeter and pressures up to 5 atmospheres, entry environments that NASA has not flown since Pioneer-Venus and Galileo. The scope of the project is broad and can be split into roughly four areas, Manufacturing/Integration, Structural Testing and Analysis, Thermal Testing and Analysis and Documentation. Manufactruing/Integration covers from raw materials, piece part fabrication to final integration on a 1-meter base diameter 45-degree sphere cone Engineering Test Unit (ETU). A key aspect of the project was to transfer as much of the manufacturing technology to industry in preparation to support future mission infusion. The forming, infusion and machining approaches were transferred to Fiber Materials Inc. and FMI then fabricated the piece parts from which the ETU was manufactured. The base 3D-woven material consists of a dual layer weave with a high density outer layer to manage recession in the system and a lower density, lower thermal conductivity inner layer to manage the heat load. At the start of the project it was understood that due to weaving limitations the heat shield was going to be manufactured from a series of tiles. And it was recognized that the development of a seam solution that met the structural and thermal requirements of the system was going to be the most challenging aspect of the project. It was also recognized that the seam design would drive the final integration approach and therefore the integration of the ETU was kept in-house within NASA. A final seam concept has been successfully developed and implemented on the ETU and will be discussed. The structural testing and analysis covers from characterization of the different layers of the infused material as functions of weave direction and temperature, to sub-component level testing such as 4-pt bend testing at sub-ambient and elevated temperature. ETU test results are used to validate the structural models developed using the element and sub-component level tests. Given the seam has to perform both structurally and aerothermally during entry a novel 4-pt bend test fixture was developed allowing articles to be tested while the front surface is heated with a laser. These tests are intended to establish the system's structural capability during entry. A broad range of aerothermal tests (arcjet tests) are being performed to develop material response models for predicting the required TPS thickness to meet a mission's needs and to evaluate failure modes. These tests establish the capability of the system and assure robustness of the system during entry. The final aspect of the project is to develop a comprehensive Design and Data Book such that a future mission will have the information necessary to adopt the technology. This presentation will provide an overview and status of the project and describe the status of the tehnology maturation level for the inner and outer planet as well as earth entry sample return missions.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN57451 , Annual International Planetary Probe Workshop (IPPW 2018); Jun 11, 2018 - Jun 15, 2018; Boulder, CO; United States
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  • 49
    Publication Date: 2019-07-20
    Description: The flow behind two rectangular roughness elements with a height approximately 38-41 percent of the boundary layer thickness was examined with a hot-wire probe. The rectangular roughness elements are oriented so that one element was at a plus 45-degree angle relative to the leading edge of the plate. A second roughness element was placed 7.16 millimeters downstream of the first one with either the same orientation relative to the leading edge of the plate, or an opposing orientation of minus 45 degrees from the leading edge. Mean mass-flux and total-temperature profiles of the flow field downstream of the tandem roughness elements were examined for mean-flow distortion. Using streak strength as a measure of mean-flow distortion, the tandem roughness elements had approximately the same amount of distortion, regardless of their relative orientation. Mass-flux fluctuation profiles show that the dominant mode downstream of the tandem roughness elements with the same orientation was similar to that of a single roughness element and centered at a frequency of approximately 55 kilohertz (kHz). The dominant instability downstream of the tandem roughness elements with opposing orientation was centered at a frequency of 65 kHz and grew more slowly than the instabilities behind the single roughness element.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NF1676L-28571 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 50
    Publication Date: 2019-07-20
    Description: Computational Fluid Dynamics (CFD) analysis is performed to investigate liquid blockage in the helium pressure line associated with the propellant (MMH) tank. If a certain amount of propellant is trapped within the helium pressure line, the question is whether the given amount of helium that is available can provide a clear helium flow path with no adverse consequences such as over pressurization of the pressure line.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GRC-E-DAA-TN60294 , Thermal and Fluids Analysis Workshop (TFAWS); Aug 20, 2018 - Aug 24, 2018; Galveston, TX; United States
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  • 51
    Publication Date: 2019-07-20
    Description: The gamma-ray sky from several hundred keV to a hundred MeV has remained largely unexplored due to the challenging nature of detecting gamma rays in this regime. At lower energies, Compton scattering is the dominant interaction process whereas at higher energies pair production dominates, with a crossover at a few MeV. Thus, an instrument designed to work in this energy range must be optimized for both Compton and pair-production events. AMEGO, the All-sky Medium Energy Gamma-ray Observatory, a Probe-class mission in consideration for the 2020 decadal survey, is designed to operate at energies from 200 keV to 〉 10 GeV with over an order of magnitude increase in sensitivity and with superior angular and energy resolution compared to previous instruments. AMEGO comprises four major subsystems: a plastic anticoincidence detector for rejecting cosmic-ray events, a silicon tracker for tracking pair-production products and tracking and measuring the energies of Compton-scattered electrons, a cadmium-zinc-telluride (CZT) calorimeter for measuring the energy and location of Compton scattered photons, and a CsI calorimeter for measuring the energy of the pair-production products at high energies. A prototype instrument, known as ComPair, is under development at NASAs Goddard Space Flight Center and the US Naval Research Laboratory. In this contribution, we provide details on the development of the silicon tracker subsystem.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66948 , 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference; Nov 10, 2018 - Nov 17, 2018; Sydney; Australia
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  • 52
    Publication Date: 2019-07-20
    Description: We describe the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X), a probe-class mission concept that will provide an unprecedented view of the X-ray sky, performing timing and spectroscopy over both a broad energy band (0.2-30 keV) and a wide range of timescales from microseconds to years. STROBE-X comprises two narrow-field instruments and a wide field monitor. The soft or low-energy band (0.2-12 keV) is covered by an array of lightweight optics (3-m focal length) that concentrate incident photons onto small solid-state detectors with CCD-level (85-175 eV) energy resolution, 100 ns time resolution, and low background rates. This technology has been fully developed for NICER and will be scaled up to take advantage of the longer focal length of STROBE-X. The higher-energy band (2-30 keV) is covered by large-area, collimated silicon drift detectors that were developed for the European LOFT mission concept. Each instrument will provide an order of magnitude improvement in effective area over its predecessor (NICER in the soft band and RXTE in the hard band). Finally, STROBE-X offers a sensitive wide-field monitor (WFM), both to act as a trigger for pointed observations of X-ray transients and also to provide high duty-cycle, high time-resolution, and high spectral-resolution monitoring of the variable X-ray sky. The WFM will boast approximately 20 times the sensitivity of the RXTE All-Sky Monitor, enabling multi-wavelength and multi-messenger investigations with a large instantaneous field of view. This mission concept will be presented to the 2020 Decadal Survey for consideration.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66148 , Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray; 10699; 1069919|SPIE Astronomical Telescopes + Instrumentation; Jun 12, 2018 - Jun 14, 2018; Austin, TX; United States
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  • 53
    Publication Date: 2019-07-19
    Description: Entire fields of science, most notably in astrophysics, rely on line-of-sight observations. In planetary science and heliophysics, the techniques of soft X-ray and energetic neutral atom (ENA) imaging also produce line-of-sight measurements. An important question is whether the geometry of the surface, for example the magnetopause, can be reconstructed using only line-of-sight observations from a single spacecraft. Under a broad range of conditions, the peak emission corresponds to the tangent to the boundary surface, such as the planetary surface or magnetopause, the so-called "limb brightening" phenomenon. Thus, line-of-sight observations frequently provide information concerning the tangent to the surfaces being observed. We present an algorithm to reconstruct the cross-section of the magnetopause using line-of-sight soft X-ray observations (and, in principle, ENA observations). The algorithm successfully reconstructs the cross section of the magnetopause in the orbit plane. The threedimensional magnetopause structure can be recovered from observations by a spacecraft whose orbit precesses around the magnetosphere.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN59848 , American Geophysical Union (AGU) Fall 2018; Dec 10, 2018 - Dec 14, 2018; Washington, DC; United States
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  • 54
    Publication Date: 2019-07-19
    Description: Coronary artery disease (CAD) surveillance has led to the development of risk stratification tools that drive clinical mitigation efforts for CAD risk. As common risk assessment tools, including the Framingham Risk Score (FRS) or Pooled Cohort Risk Equations, have insufficient accuracy on an individual level to meet NASAs stringent screening guidelines, NASA has required new approaches to address the risk of catastrophic cardiovascular (CV) medical events among astronauts. Coronary artery calcium (CAC) scanning has emerged as the current best tool to enhance CV risk assessment in asymptomatic individuals, with risk information incremental to FRS data.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN49078 , Aerospace Medical Association Annual Scientific Meeting (AsMA 2018); May 06, 2018 - May 10, 2018; Dallas, TX; United States
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  • 55
    Publication Date: 2019-07-19
    Description: The Bellagio II Summit sought to correlate current ISS (International Space Station) Space Medicine practice in the screening/assessment and management of CAD (Coronary Artery Disease) and to identify terrestrial applications for the general population pertaining to primary, secondary and tertiary diagnoses and treatments. We identified current Space Medicine practice for screening and monitoring cosmonaut and astronaut in the pre-, in-, and post-flight mission phases. We will discuss current Space Medicine standards and guidelines in the recognition and monitoring of CAD development, stabilization, and regression.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN48747 , Aerospace Medical Association (AsMA) Annual Scientific Meeting 2018; May 06, 2018 - May 10, 2018; Dallas, TX; United States
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  • 56
    Publication Date: 2019-07-19
    Description: Hydroxyapatites single crystals have been investigated their applications as the laser host material. Czochralksi and flux growth methods have been utilized to achieve single crystals. Because of their bioactivities with tissues these have attracted interest for bone applications. For low temperature processing we have used several techniques. We utilized some organic melt and oriented the grains by the directional solidification method. This organic treated material has different characteristics than coarsened oxide materials. Our approach involved low temperature processing using nano-engineered powders of the material system MgO-Na2O-K2O-CaO-SrO-SiO2 and also borates were processed by sintering and grain growth. Our results indicate that substitution of calcium and strontium with some other elements such as gallium and magnesium have great potential to improve the mechanical properties of bones.
    Keywords: Aerospace Medicine
    Type: M18-6491 , SPIE (Defense + Commercial Sensing and Imaging) 2018; Apr 15, 2018 - Apr 19, 2018; Orlando, FL; United States
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  • 57
    Publication Date: 2019-07-20
    Description: Future astronomy missions using x-ray transition-edge sensor (TES) microcalorimeters, such as X-IFU on Athena, will require large arrays of 1000s of pixels fabricated on a single wafer. To wire out so many pixels the current array designs have pixels with different rotational orientations. Fabrication is done in multiple layers and so, dependent on method, there is potential for spatial misalignment between layers. Because of the variation of orientation of pixels, misalignment may not impact each pixel equally. This has the potential to degrade the achievable uniformity of performance across an array. How well aligned do different layers need to be? How does sensitivity to misalignment depend on choice of pixel design?
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN62871 , Applied Superconductivity Conference 2018; Oct 28, 2018 - Nov 02, 2018; Seattle, WA; United States
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  • 58
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    In:  CASI
    Publication Date: 2019-07-20
    Description: The LISA Mission proposal was selected by ESA's Science Program Committee (SPC) for the L3 Cosmic Visions launch opportunity, and is currently in a Phase A mission formulation study. An essential component of the instrument is a set of optical telescopes that make precision displacement measurements between pairs of proof masses that are flying drag-free in three separate satellites. We discuss the key requirements on the telescope, the current design, and discuss progress toward solving some of the key challenges for realizing the telescope designs.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN62893 , Annual Mirror Technology SBIR/STTR Workshop; Nov 05, 2018 - Nov 07, 2018; El Segundo, CA; United States
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  • 59
    Publication Date: 2019-07-20
    Description: Outline: Background; Terrestrial experience -Initial investigation into MSK (MusculoSKeletal) injuries -MSK Medicine Program -Training injuries -NBL (Neutral Buoyancy Laboratory) EMU (Extravehicular activity Mobility Unit) Work Hardening Program -Return to duty -Post-flight reconditioning program; Inflight musculoskeletal conditions; Lunar Surface Operations; Post-flight injuries.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN61166 , UCSD Co-Investigator Workshop; Sep 24, 2018; Bethesda, MD; United States
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  • 60
    Publication Date: 2019-07-20
    Description: In this work, a one-dimensional methodology for simulating shock tubes is developed. The model accounts for the viscous interactions of the shock with the shock tube wall by adding an area change source term in the 1-D conservation equations corresponding to the boundary layer growth. This source term corresponds to the mass and energy going into the boundary layer. The boundary layer growth is computed using a simple model with a scaling factor. This scale factor is used to tailor a solution to match the deceleration profile of a shock tube test. In doing so, not only will the source term take into account boundary layer losses, it will also cover any effect due to radiative cooling loses from the gas. For this study, the Electric Arc Shock Tube(EAST) facility at NASA Ames Research Center is modeled for Earth reentry conditions. The purpose of this paper is to investigate if anomalies identified for certain conditions in the EAST data are due to shock deceleration. These anomalies include measuring electron number density above equilibrium predictions and observing that radiance profiles can continually increase behind the shock, never reach steady state, for certain shots (typically those less than 10 km/s). An eleven species air mixture is chosen to study the chemistry of the flow. Comparisons of the simulations to the experimental results are presented. Good agreement with the shock deceleration profiles was achieved by tuning in the boundary layer scale factor. The temperature as well as electron number density increases behind the shock, as has also been observed in the experiments. Finally, radiance comparisons between results from NEQAIR and experiments also show good agreement for some shots, but significant discrepancies are still observed for others.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN56934 , AIAA Aviation Forum 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 61
    Publication Date: 2019-07-20
    Description: Snowballs are transient events observed in HgCdTe detectors with a sudden increase of charge in a few pixels. They appear between consecutive reads of the detector, after which the affected pixels return to their normal behavior. The origin of the snowballs is unknown, but it was speculated that they could be the result of alpha decay of naturally radioactive contaminants in the detectors, but a cosmic ray origin cannot be ruled out. Even though previous studies predicted a low rate of occurrence of these events, and consequently, a minimal impact on science, it is interesting to investigate the cause or causes that may generate snowballs and their impact in detectors designed for future missions. We searched for the presence of snowballs in the dark current data in Euclid and Wide Field Infrared Survey Telescope (WFIRST) detectors tested in the Detector Characterization Laboratory at Goddard Space Flight Center. Our investigation shows that for Euclid and WFIRST detectors, there are snowballs that appear only one time, and others that repeat in the same spatial localization. For Euclid detectors, there is a correlation between the snowballs that repeat and bad pixels in the operational masks (pixels that do not fulfill the requirements to pass spectroscopy noise, photometry noise, quantum efficiency, and/or linearity). The rate of occurrence for a snowball event is about 0.9 snowballs/hr. in Euclid detectors (for the ones that do not have associated bad pixels in the mask), and about 0.7 snowballs/hr. in PV3 Full Array Lot WFIRST detectors.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66820 , SPIE Astronomical Telescope + Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 62
    Publication Date: 2019-07-20
    Description: The Human Research Program funded the development of the Integrated Medical Model (IMM) to quantify the medical component of overall mission risk. The IMM uses Monte Carlo simulation methodology, incorporating space flight and ground medical data, to estimate the probability of mission medical outcomes and resource utilization. To determine the credibility of IMM output, the IMM project team completed two validation studies that compared IMM predicted output to observed medical events from a selection of Shuttle Transportation System (STS) and International Space Station (ISS) missions. The validation study results showed that the IMM underpredicted the occurrence of ~10% of the modeled medical conditions for the STS missions and overpredicted ~20% of the modeled medical conditions for the ISS missions. These findings imply that the strength of IMM predictions to inform decisions depends on simulated mission specifications including length. This discrepancy could result from medical recording differences between ISS and STS that possibly influence observed incidence rates, IMM combining all "mission type" data as constant occurrence rate or fixed proportion across both mission types, misspecification of symptoms to conditions, and gaps in the literature informing the model. Some of these issues will be alleviated by updating the IMM source data through incorporation of the observed validation data.
    Keywords: Aerospace Medicine
    Type: GRC-E-DAA-TN60336 , Probabilistic Safety Assessment and Management (PSAM 14); Sep 16, 2018 - Sep 21, 2018; Los Angeles, CA; United States
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  • 63
    Publication Date: 2019-07-20
    Description: The Arcus mission, proposed for NASA's 2016 Astrophysics Medium Explorer (MIDEX) announcement of opportunity, will use X-ray spectroscopy to detect previously unaccounted quantities of normal matter in the Universe. The Arcus mission design uses 4:1 lunar resonance to provide a stable orbit for visibility of widely-dispersed targets, in a low background radiation environment, above the Van Allen belts for the minimum two-year science mission. Additional ad-vantages of 4:1 resonance are long term stability without maintenance maneu-vers, eclipses under 4.5 hours, perigee radius approximately 12 Re for data download, and streamlined operational cadence with approximately 1 week orbit period.
    Keywords: Astrophysics
    Type: AAS 18-271 , ARC-E-DAA-TN60130 , AAS/AIAA Astrodynamics Specialist Conference; Aug 19, 2018 - Aug 23, 2018; Snowbird, UT; United States
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  • 64
    Publication Date: 2019-07-13
    Description: As part of our work on nitrogen-rich ices, the IR spectra and band strengths used in a recent paper to identify and quantify radiation-induced changes in an N2+H2O ice near 15 K are examined, along with reports of (i) a chemical tracer for N2+H2O ices, (ii) a new IR feature of solid N2, and (iii) a striking 15N isotopic enrichment. Problems are found for each IR band strength used and for each of the three claims made, to the extent that none are supported by the results presented to date. In contrast, new work presented here, combined with several older investigations, strongly supports the formation of di- and triatomic nitrogen oxides in irradiated N2-rich ices. Observations and trends in the chemistry of N2-rich icy solids are described, and conclusions are drawn. A considerable amount of material from previous chemical studies of N2-rich systems, spanning more than a century, is brought together for the rst time and used to examine the chemistry of N2-rich ices in extraterrestrial environments. Needs are identied and suggestions made for future studies of N2-rich interstellar and planetary ice analogs.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64347 , Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 867; 2; 160
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  • 65
    Publication Date: 2019-07-13
    Description: This work describes multi-site optical polarimetric observations of several radio-loud Narrow Line Seyfert 1 galaxies. This source class, and the sources in this study, were discovered to be detectable at gamma-ray energies by the Large Area Telescope (LAT) aboard the Fermi satellite. GSFC has played a key role in the development, launch, and operation of Fermi/LAT.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN63180 , Astronomy & Astrophysics (ISSN 0004-6361) (e-ISSN 1432-0746); 618; A92
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  • 66
    Publication Date: 2019-07-13
    Description: Accurate forecasting of the properties of coronal mass ejections (CMEs) as they approach Earth is now recognized as an important strategic objective for both NOAA and NASA. The time of arrival of such events is a key parameter, one that had been anticipated to be relatively straightforward to constrain. In this study, we analyze forecasts submitted to the Community Coordinated Modeling Center at NASA's Goddard Space Flight Center over the last 6 years to answer the following questions: (1) How well do these models forecast the arrival time of CME-driven shocks? (2) What are the uncertainties associated with these forecasts? (3) Which model(s) perform best? (4) Have the models become more accurate during the past 6 years? We analyze all forecasts made by 32 models from 2013 through mid-2018, and additionally focus on 28 events, all of which were forecasted by six models. We find that the models are generally able to predict CME-shock arrival times, in an average sense, to within 10 hr, but with standard deviations often exceeding 20 hr. The best performers, on the other hand, maintained a mean error (bias) of 1 hr, a mean absolute error of 13 hr, and a precision (standard deviation) of 15 hr. Finally, there is no evidence that the forecasts have become more accurate during this interval. We discuss the intrinsic simplifications of thevarious models analyzed, the limitations of this investigation, and suggest possible paths to improve these forecasts in the future.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN65897 , Space Weather (ISSN 1539-4956) (e-ISSN 1542-7390); 16; 9; 1245-1260
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  • 67
    Publication Date: 2019-07-13
    Description: We present results of recent Neutron Star Interior Composition Explorer (NICER) observations of the accreting millisecond X-ray pulsar (AMXP) IGR J17062-6143 that show that it resides in a circular, ultracompact binary with a 38-minute orbital period. NICER observed the source for 26 kiloseconds over a 5.3-day span in 2017 August, and again for 14 and 11 kiloseconds in 2017 October and November, respectively. A power spectral analysis of the August exposure confirms the previous detection of pulsations at 163.656 Hertz in Rossi X-ray Timing Explorer (RXTE) data, and reveals phase modulation due to orbital motion of the neutron star. A coherent search for the orbital solution using the Z squared method finds a best-fitting circular orbit with a period of 2278.21 seconds (37.97 minutes), a projected semimajor axis of 0.00390 lt-s (Localization Test Statistic), and a barycentric pulsar frequency of 163.6561105 Hertz. This is currently the shortest known orbital period for an AMXP. The mass function is 9.12 times 10 (sup minus 8) solar mass, presently the smallest known for a stellar binary. The minimum donor mass ranges from approximately 0.005 to 0.007 times the solar mass for a neutron star mass from 1.2 to 2 times the solar mass. Assuming mass transfer is driven by gravitational radiation, we find donor mass and binary inclination bounds of 0.0175-0.0155 times the solar mass and 19 degrees less than i less than 27.5 degrees, where the lower and upper bounds correspond to 1.4 and 2 times the solar mass neutron stars, respectively. Folding the data accounting for the orbital modulation reveals a sinusoidal profile with fractional amplitude 2.04 plus or minus 0.11 percent (0.3-3.2 kiloelectronvolts).
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN61305 , Astrophysical Journal (ISSN 2041-8205) (e-ISSN 2041-8213); 858; 2; L13
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  • 68
    Publication Date: 2019-07-13
    Description: We present a second epoch of Chandra observations of the Type Ia Large Magellanic Cloud supernova remnant(SNR) 0509-68.7 (N103B) obtained in 2017. When combined with the earlier observations from 1999, we have a17.4 year baseline with which we can search for evidence of the remnant's expansion. Although the lack of strongpoint source detections makes absolute image alignment at the necessary accuracy impossible, we can measure thechange in the diameter and the area of the remnant, and find that it has expanded by an average velocity of 4170(2860, 5450) km s1. This supports the picture of this being a young remnant; this expansion velocity correspondsto an undecelerated age of 850 years, making the real age somewhat younger, consistent with results from lightecho studies. Previous infrared observations have revealed high densities in the western half of the remnant, likelyfrom circumstellar material, so it is probable that the real expansion velocity is lower on that side of the remnantand higher on the eastern side. A similar scenario is seen in Kepler's SNR. N103B joins the rare class ofMagellanic Cloud SNRs with measured proper motions.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN62730 , Astrophysical Journal Letters (ISSN 2041-8205) (e-ISSN 2041-8213); 865; 2
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  • 69
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    In:  Other Sources
    Publication Date: 2019-07-13
    Description: The Neutron star Interior Composition Explorer (NICER) is an International Space Station (ISS) mission of opportunity that was selected as part of NASA's Explorer Program. It is the first NASA mission dedicated to the study of neutron stars and has been in operation since its 13 June 2017 installation on the ISS (following a 3 June launch), nearly 50 years after the discovery of neutron stars. NICER studies the energetics, dynamics and structure of neutron stars through observations in the soft X-ray band, exploring rapid brightness and spectral fluctuations with high-precision time stamping and spectroscopy of individually detected X-ray photons. Compared with its predecessor X-ray timing astrophysics mission, the Rossi X-ray Timing Explorer(RXTE), which launched over two decades ago, NICER provides order-of-magnitude improvements in spectral resolution, absolute timing resolution and sensitivity.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN62153 , Nature Astronomy (e-ISSN 2397-3366); 1; 895
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  • 70
    Publication Date: 2019-07-13
    Description: We introduce a modified version of the ASGARD code (Automated Selection and Grouping of events in A/A Regional Data). Originally written to detect and group brightenings ("events") in the AIA EUV channels, it now includes the sparsity DEM inversion method and instead detects emission measure enhancements in different temperature bins. Ultimately, the goal is to automatically determine heating and cooling rates in different coronal structures.
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN61897 , Solar Dynamics Observatory (SDO) Workshop, Catalyzing Solar Connections; Oct 29, 2018 - Nov 02, 2018; Ghent; Belgium
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  • 71
    Publication Date: 2019-07-13
    Description: The International Space Station is a unique laboratory for performing investigations that affect human health both in space and on Earth. During its time in orbit, the space station has enabled research that is providing a better understanding of many aspects of human health including aging, trauma, disease and environmental impacts. Driven by the need to support astronaut health, several biological and human physiological investigations have yielded important results that we on Earth can also benefit from. These results include new ways to mitigate bone loss, insights into bacterial behavior, and innovative wound-healing techniques. Advances in telemedicine, disease models, psychological stress response systems, nutrition and cell behavior are just a few more examples of the benefits that have been gained from applying studies in orbit to human health back on Earth.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN58554 , Expo-Ciencias Latinoamericana ESI AMLAT 2018; Jul 02, 2018 - Jul 06, 2018; Antofagasta; Chile
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  • 72
    Publication Date: 2019-07-13
    Description: The External Active Thermal Control System (EATCS) provides cooling for all pressurized modules and the main Power Distribution Electronics (PDE) on the International Space Station (ISS). There are 2 EATCS loops (Loop A and Loop B) which includes 3 deployable radiators. Each deployable radiator contains 2 flow paths to provide heat rejection.Telemetry monitoring identified a coolant (liquid ammonia) leak in EATCS Loop B. Robotic External Leak Locator (RELL) scans found higher concentrations of vaporous ammonia near the EATCS Loop B Radiator #3 Flow Path #2. On May 3, 2017, the EATCS Loop B Radiator #3 Flow Path #2 was isolated and vented. As of the data to date, the ammonia leak has ceased. The purpose of this presentation is to discuss the analysis for venting the EATCS Loop B Radiator #3 Flow Path #2. Venting analysis is performed to determine the worst case time to empty the flow path and maximum thrusts imposed on the ISS. Flight controllers and engineers in the Mission Control Center (MCC) uses this data to develop operational procedures and perform the vent safely. It was predicted that the worst case time to empty the EATCS Loop B Radiator #3 Flow Path #2 was ~ 60 minutes. The predicted maximum thrusts were ~ 11 lbf (49 N) at the start of the vent and ~10 lbf (45 N) after the system reaches saturation.The vent was successfully performed and took ~ 20 minutes to empty the EATCS Loop B Radiator #3 Flow Path #2. Using telemetry from the day of the vent, analysis determined the time to empty the EATCS Loop B Radiator #3 Flow Path #2 would be ~13 minutes. The predictive analysis used worst case inputs and assumptions which bounded the actual results. Telemetry is not available to correlate actual thrust with the predicted maximum thrusts. However, by using Russian Thrusters for ISS attitude control, attitude control telemetry indicated the flight attitude was maintained.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JSC-E-DAA-TN60440 , JSC-E-DAA-TN60077 , Thermal & Fluids Analysis Workshop (TFAWS); Aug 20, 2018 - Aug 24, 2018; Galveston, TX; United States
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  • 73
    Publication Date: 2019-07-13
    Description: We present an X-ray spectral and timing analysis of two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the transient Be X-ray binary SAX J2103.5+4545 during its 2016 April outburst, which was characterized by the highest flux since NuSTAR's launch. These observations provide detailed hard X-ray spectra of this source during its bright precursor flare and subsequent fainter regular outburst for the first time. In this work, we model the phase-averaged spectra for these observations with a negative and positive power law with an exponential cutoff (NPEX - Negative and Positive power-laws EXponential) model and compare the pulse profiles at different flux states. We found that the broadband pulse profile changes from a three-peaked pulse in the first observation to a two-peaked pulse in the second observation, and that each of the pulse peaks has some energy dependence. We also perform pulse-phase spectroscopy and fit phase-resolved spectra with NPEX to evaluate how spectral parameters change with pulse phase. We find that while the continuum parameters are mostly constant with pulse phase, a weak absorption feature at approximately 12 kiloelectronvolts which might, with further study, be classified as a cyclotron line, does show strong pulse-phase dependence.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN59894 , The Astrophysical Journal (ISSN 2041-8205) (e-ISSN 2041-8213); 852; 2; 132
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  • 74
    facet.materialart.
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    In:  CASI
    Publication Date: 2019-07-13
    Description: A laser interferometer space-based gravitational wave observatory requires an optical telescope to efficiently transfer laser light between pairs of widely-separated sciencecraft. The application is precision interferometric metrology, and therefore requires the telescope to have high optical pathlength stability, and low scattered light performance. We summarize recent activity on the development of a telescope to meet requirements for the LISA mission, including optimization of the optical design, development of a CAD and finite element model, and thinking about how to live with a high level of particulate contamination on the optics and still meet challenging scattered light requirements.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN56097 , LISA Consortium Meeting; Apr 09, 2018 - Apr 11, 2018; Hannover; Germany
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  • 75
    Publication Date: 2019-07-13
    Description: Infrared spectra of ices containing alcohols that are known or potential interstellar molecules are examined before and after irradiation with 1 MeV protons at ~20 K. The low-temperature oxidation (hydrogen loss) of six alcohols is followed, and conclusions are drawn based on the results. The formation of reaction products is discussed in terms of the literature on the radiation chemistry of alcohols and a systematic variation in their structures. The results from these new laboratory measurements are then applied to a recent study of propargyl alcohol. Connections are drawn between known interstellar molecules, and several new reaction products in interstellar ices are predicted.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN57109 , GSFC-E-DAA-TN56717 , The Astrophysical Journal; 857; 2; 89
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  • 76
    Publication Date: 2019-07-13
    Description: We examine the generation of kappa distributions in the solar wind plasma near 1 au. Several mechanisms are mentioned in the literature, each characterized by a specific relationship between the solar wind plasma features, the interplanetary magnetic field (IMF), and the kappa index-the parameter that governs the kappa distributions. This relationship serves as a signature condition that helps the identification of the mechanism in the plasma. In general, a mechanism that generates kappa distributions involves a single or a series of stochastic or physical processes that induces local correlations among particles. We identify three fundamental solar wind plasma conditions that can generate kappa distributions, noted as (i) Debye shielding, (ii) frozen IMF, and (iii) temperature fluctuations, each one prevailing in different scales of solar wind plasma and magnetic field properties. Moreover, our findings show that the kappa distributions, and thus, their generating mechanisms, vary significantly with solar wind features: (i) the kappa index has different dependence on the solar wind speed for slow and fast modes, i.e., slow wind is characterized by a quasi-constant kappa index, K (is) approx. 4.3 +/- 0.7, while fast wind exhibits kappa indices that increase with bulk speed; (ii) the dispersion of magnetosonic waves is more effective for lower kappa indices (i.e., further from thermal equilibrium); and (iii) the kappa and polytropic indices are positively correlated, as it was anticipated by the theory.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN52478 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 853; 2
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  • 77
    Publication Date: 2019-07-13
    Description: The study of time-dependent solar active region (AR) morphology and its relation to eruptive events requires analysis of imaging data obtained in multiple wavelength domains with differing spatial and time resolution, ideally in combination with 3D physical models. To facilitate this goal, we have undertaken a major enhancement of our IDL-based simulation tool, GX_Simulator, previously developed for modeling microwave and X-ray emission from flaring loops, to allow it to simulate quiescent emission from solar ARs. The framework includes new tools for building the atmospheric model and enhanced routines for calculating emission that include new wavelengths. In this paper, we use our upgraded tool to model and analyze an AR and compare the synthetic emission maps with observations. We conclude that the modeled magneto-thermal structure is a reasonably good approximation of the real one.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN53773 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 853; 1; 66
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  • 78
    Publication Date: 2019-07-13
    Description: James Webb Space Telescope (JWST) is a large infrared observing space telescope which will launch in 2020. The observatory is comprised of 4 major subsystems; (1) Optical Telescope Element (OTE), (2) Integrated Science Instrument Module (ISIM), (3) Sunshield, (4) Spacecraft Bus. The OTE and ISIM are integrated together at Goddard Space Flight Center to form the OTIS assembly,
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN57385 , SPIE Astronomical Telescopes + Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 79
    Publication Date: 2019-07-13
    Description: Aerobic fitness is best measured by Maximal Aerobic Capacity or VO2 Max which is defined as a measure of oxygen utilization and transport. Increased Vo2 max indicates improved oxygen consumption during high level exercise and is widely accepted as a predictor of an individual's likelihood of successfully completing a demanding task. As such, agencies and organizations have adopted VO2 max as part of a comprehensive set of physical requirements. The purpose of this study is to review the literature and existing medical and occupational VO2 max data, to propose a VO2 max standard for NASA astronauts for training and spaceflight.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN47910 , Aerospace Medical Association Conference; May 07, 2018 - May 10, 2018; Dallas, TX; United States
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  • 80
    Publication Date: 2019-07-13
    Description: The COSmIC facility was developed at NASA Ames to study interstellar, circumstellar and planetary analogs in the laboratory]. COSmIC stands for "Cosmic Simulation Chamber" and is dedicated to the study of neutral and ionized molecules and nanoparticles under the low temperature and high vacuum conditions that are required to simulate space environments. COSmIC integrates a variety of instruments that allow generating; processing and monitoring simulated space conditions in the laboratory. It is composed of a Pulsed Discharge Nozzle (PDN) expansion that generates a plasma in a free supersonic jet expansion coupled to high-sensitivity, complementary in situ diagnostic tools, used for the detection and characterization of the species present in the expansion: a Cavity Ring Down Spectroscopy (CRDS) and fluorescence spectroscopy systems for photonic detection, and a Reflectron Time-Of-Flight Mass Spectrometer (ReTOF-MS) for mass detection. Recent advances achieved in laboratory astrophysics using COSmIC will be presented, in particular in the domain of the diffuse interstellar bands (DIBs) and the monitoring, in the laboratory, of the formation of dust grains and aerosols from their gasphase molecular precursors in environments as varied as circumstellar outflows and planetary atmospheres. Plans for future laboratory experiments on cosmic molecules and grains in the growing field of laboratory astrophysics (NIR-MIR CRDS, Laser Induced Fluorescence spectra of cosmic molecule analogs and the laser induced incandescence spectra of cosmic grain analogs) will also be addressed as well as the implications of the on-going studies for astronomy.
    Keywords: Astrophysics
    Type: ARC-E-DAA-TN55634 , American Astronomical Society; Jun 03, 2018 - Jun 07, 2018; Denver, CO; United States
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  • 81
    Publication Date: 2019-07-13
    Description: We report the first extragalactic detection of the complex organic molecules (COMs) dimethyl ether (CH3OCH3) and methyl formate (CH3OCHO) with the Atacama Large Millimeter/submillimeter Array (ALMA). These COMs, together with their parent species methanol (CH3OH), were detected toward two 1.3 mm continuum sources in the N 113 star-forming region in the low-metallicity Large Magellanic Cloud (LMC). Rotational temperatures (Trot approx. 130 K) and total column densities (Nrot 10 approx. 16 cm2) have been calculated for each source based on multiple transitions of CH3OH. We present the ALMA molecular emission maps for COMs and measured abundances for all detected species. The physical and chemical properties of two sources with COMs detection, and the association with H2O and OH maser emission, indicate that they are hot cores. The fractional abundances of COMs scaled by a factor of 2.5 to account for the lower metallicity in the LMC are comparable to those found at the lower end of the range in Galactic hot cores. Our results have important implications for studies of organic chemistry at higher redshift.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN66669 , GSFC-E-DAA-TN54004 , The Astrophysical Journal Letters (ISSN 2041-8205) (e-ISSN 2041-8213); 853; 2; L19
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  • 82
    Publication Date: 2019-07-13
    Description: We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN54133 , GSFC-E-DAA-TN54129 , Journal of Astronomical Telescopes, Instruments and Systems (ISSN 2329-4124) (e-ISSN 2329-4221); 4; 1; 011210
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  • 83
    Publication Date: 2019-07-13
    Description: New initiatives to begin Lunar and Martian human surface operations within the next few decades are illustrative of the resurgence of interest in human space exploration. However, as with all exploration, there are risks. The previous manned missions to the Moon highlight a major hazard for future human exploration of the Moon and beyond: surface dust. Not only did the dust cause mechanical and structural integrity issues with the suits, the dust 'storm' generated upon reentrance into the crew cabin caused "lunar hay fever" and "almost blindness.". It was further reported that the allergic response to the dust worsened with each exposure. Due to the prevalence of these high exposures, the Human Research Roadmap developed by NASA identifies the Risk of Adverse Health and Performance Effects of Celestial Dust Exposure as an area of concern.
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN52126 , International Conference on Atmospheric Dust (Dust 2018); May 29, 2018 - May 31, 2018; Bari; Italy
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  • 84
    Publication Date: 2019-07-13
    Description: In the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet. Aided by the universality of the laws of physics and chemistry, we turn to Earth's biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere. Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a comprehensive overview of our current understanding of potential exoplanet biosignatures, including gaseous, surface, and temporal biosignatures. We additionally survey biogenic spectral features that are well known in the specialist literature but have not yet been robustly vetted in the context of exoplanet biosignatures. We briefly review advances in assessing biosignature plausibility, including novel methods for determining chemical disequilibrium from remotely obtainable data and assessment tools for determining the minimum biomass required to maintain short-lived biogenic gases as atmospheric signatures. We focus particularly on advances made since the seminal review by Des Marais et al. The purpose of this work is not to propose new biosignature strategies, a goal left to companion articles in this series, but to review the current literature, draw meaningful connections between seemingly disparate areas, and clear the way for a path forward.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN56547 , Astrobiology (ISSN 1531-1074) (e-ISSN 1557-8070); 18; 6; 663-708
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  • 85
    Publication Date: 2019-07-13
    Description: We stack the rest-frame ultraviolet spectra of N = 14 highly magnified gravitationally lensed galaxies at redshifts 1.6 〈 z 〈 3.6. The resulting new composite spans 900 〈 lambda rest 〈 3000 Angstrom, with a peak signal-to-noise ratio of 103 per spectral resolution element (approximately 100 km s (exp -1)). It is the highest signalto-noise ratio, highest spectral resolution composite spectrum of z approximately 2-3 galaxies yet published. The composite reveals numerous weak nebular emission lines and stellar photospheric absorption lines that can serve as new physical diagnostics, particularly at high redshift with the James Webb Space Telescope (JWST). We report equivalent widths to aid in proposing for and interpreting JWST spectra. We examine the velocity profiles of strong absorption features in the composite, and in a matched composite of z approximately 0 COS/HST galaxy spectra. We find remarkable similarity in the velocity profiles at z approximately 0 and z approximately 2, suggesting that similar physical processes control the outflows across cosmic time. While the maximum outflow velocity depends strongly on ionization potential, the absorptionweighted mean velocity does not. As such, the bulk of the high-ionization absorption traces the low-ionization gas, with an additional blueshifted absorption tail extending to at least approximately 2000 km s (exp -1). We interpret this tail as arising from the stellar wind and photospheres of massive stars. Starburst99 models are able to replicate this high-velocity absorption tail. However, these theoretical models poorly reproduce several of the photospheric absorption features, indicating that improvements are needed to match observational constraints on the massive stellar content of star-forming galaxies at z approximately 2. We publicly release our composite spectra.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN54572 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 853; 1
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  • 86
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN51838 , 2018 NASA Human Research Program Investigators'' Workshop; Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 87
    Publication Date: 2019-07-13
    Description: Final Paper and not the abstract is attached. see attached
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN53742 , Annual IEEE Aerospace Conference 2018; Mar 03, 2018 - Mar 10, 2018; Big Sky, MT; United States
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  • 88
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN50638 , AAS Meeting; Jan 08, 2018 - Jan 12, 2018; National Harbor, MD; United States
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  • 89
    Publication Date: 2019-07-19
    Description: Medical simulation is a useful tool that can be used to train personnel, develop medical processes, and assist cross-disciplinary communication. Medical simulations have been used in the past at NASA for these purposes, however they are usually created ad hoc. A stepwise approach to scenario development has not previously been used. The NASA Exploration Medical Capability (ExMC) created a medical scenario development tool to test medical procedures, technologies, concepts of operation and for use in systems engineering (SE) processes.
    Keywords: Aerospace Medicine
    Type: JSC-CN-40664 , NASA Human Research Program Investigators'' Workshop (HRP IWS 2018); Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 90
    Publication Date: 2019-07-19
    Description: Historical solar particle events (SPEs) provide context for some understanding of acute radiation exposure risk to astronauts traveling outside of low Earth orbit. Modeling of potential doses delivered to exploration crewmembers anticipates limited radiation-induced health impacts, including prodromal symptoms of nausea, emesis, and fatigue, but suggests that more severe clinical manifestations are unlikely. Recent large animal-model research in space-analogs closely mimicking SPEs has identified coagulopathic events independent of the hematopoietic sequelae of higher radiation doses, similar in manifestation to disseminated intravascular coagulation (DIC). We explored the challenges of clinical management of radiation-related clinical manifestations, using currently accepted modeling techniques and anticipated physiological sequelae, to identify medical capabilities needed to successfully manage SPE-induced radiation illnesses during exploration spaceflight.
    Keywords: Aerospace Medicine
    Type: JSC-CN-40647 , NASA Human Research Program Investigators'' Workshop (HRP IWS 2018); Jan 22, 2018 - Jan 25, 2018; Galveston, TX; United States
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  • 91
    Publication Date: 2019-07-13
    Description: The high mass X-ray binary Cepheus X-4, during its 2014 outburst, showed evidence for an asymmetric cyclotron line in its hard X-ray spectrum. The 2014 spectrum provides one of the clearest cases of an asymmetric line profile among all studied sources with Cyclotron Resonance Scattering Features (CRSF). We present a phase-resolved analysis of NuSTAR and Suzaku data taken at the peak and during the decline phases of this outburst. We find that the pulse-phased resolved spectra are well-fit by a single, symmetric cyclotron feature. The fit parameters vary strongly with pulse phase: most notably the central energy and depth of the cyclotron feature, the slope of the power-law component, and the absorbing column density. We synthesise a phase averaged spectrum using the best-fitting parameters for these individual pulse phases, and find that this combined model spectrum has a similar asymmetry in the cyclotron features as discovered in phase-averaged data. We conclude that the pulse phase resolved analysis with simple symmetric line profiles when combined can explain the asymmetry detected in the phase-averaged data.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN63849 , Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711) (e-ISSN 1365-2966); 482; 3; 2902-2912
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  • 92
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-E-DAA-TN62315 , Payload Operations and Integration Working Groups (POIWG) 2018; Oct 23, 2018 - Oct 25, 2018; Huntsville, AL; United States
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  • 93
    Publication Date: 2019-07-13
    Description: Radiative heating computations are performed for a range of high speed Earth entry experiments conducted in the Electric Arc Shock Tube at NASA Ames. The nonequilibrium radiative transport equations are solved in NEQAIR using flow field variables from the full facility CFD simulations of the EAST shock tube performed by US3D ow solver. These physics-based flow calculations lead to a significantly different post-shock gas state and associated radiation field as compared to that based on a simplified but computationally inexpensive calculation for flow over a blunt-body with appropriate initial conditions. The radiation spectra and radiance profiles are computed for an extensive range of wavelengths, from deep VUV to IR, which are pertinent to the emission characteristics of high enthalpy shock waves in air. The radiation properties of the shocked gas are calculated both in the nonequilibrium region at the shock, and in the equilibrium region behind the shock. Numerical predictions are found to be consistent with the experimental observations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN62943 , AIAA Aviation Forum 2018; Jun 23, 2018 - Jun 29, 2018; Dallas, TX; United States
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  • 94
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN62864 , IXPE (Imaging X-ray Polarimetry Explorer) Science Collaboration Meeting; Nov 05, 2018 - Nov 09, 2018; Rome; Italy
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  • 95
    Publication Date: 2019-07-13
    Description: Large space structures are capable of large thermal deformations in the space environment. A case of large-scale thermal deformation was observed in the analysis of the Near Earth Asteroid Scout solar sail, with predicted tip displacements of more than one meter in seven-meter booms. Experimental data supports the broad conclusions of the analysis, but shows poor agreement on the details of the thermal deformation. Prediction that is precise enough to drive engineering decisions will require coupled thermal-stress analysis with features that are not found in current multiphysics codes. This paper describes a simple method for stepwise coupling between commercial nonlinear stress analysis software and radiative thermal analysis software. Results are presented for a round stainless steel tube, which is a common case in existing literature.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NF1676L-27327 , AIAA SciTech; Jan 08, 2018 - Jan 12, 2018; Kissimmee; United States
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  • 96
    Publication Date: 2019-07-13
    Description: We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released 11 year data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). While we find no evidence for a GWB, we place constraints on a population of inspiraling supermassive black hole (SMBH) binaries, a network of decaying cosmic strings, and a primordial GWB. For the first time, we find that the GWB constraints are sensitive to the solar system ephemeris (SSE) model used and that SSE errors can mimic a GWB signal. We developed an approach that bridges systematic SSE differences, producing the first pulsar-timing array (PTA) constraints that are robust against SSE errors. We thus place a 95% upper limit on the GW-strain amplitude of A (sub GWB) 〈 1.45 10 (exp -15) at a frequency of f=1 yr(exp -1) for a fiducial f (exp -2/3) power-law spectrum and with interpulsar correlations modeled. This is a factor of approximately 2 improvement over the NANOGrav nine-year limit calculated using the same procedure. Previous PTA upper limits on the GWB (as well as their astrophysical and cosmological interpretations) will need revision in light of SSE systematic errors. We use our constraints to characterize the combined influence on the GWB of the stellar mass density in galactic cores, the eccentricity of SMBH binaries, and SMBH-galactic-bulge scaling relationships. We constrain the cosmic-string tension using recent simulations, yielding an SSE-marginalized 95% upper limit of G (sub mu) 〈 5.3 10(exp -11) - a factor of approximately 2 better than the published NANOGrav nine-year constraints. Our SSE-marginalized 95% upper limit on the energy density of a primordial GWB (for a radiation-dominated post-inflation universe) is omega (sub GWB)(f) h (exp 2) 〈 3.4 10 (exp -10).
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN59128 , Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 859; 1; 47
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  • 97
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Astrophysics
    Type: MSFC-E-DAA-TN61308 , AIAA Space Forum; Sep 17, 2018 - Sep 19, 2018; Orlando, FL; United States
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  • 98
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN59398 , International Planetary Probe Workshop; Jun 11, 2018 - Jun 15, 2018; Boulder, CO; United States
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  • 99
    Publication Date: 2019-07-13
    Description: I present a description of the Kepler and TESS mission planet search pipelines, and discuss key science results achieved by Kepler and those expected for the TESS Mission.
    Keywords: Astrophysics
    Type: ARC-E-DAA-TN58664 , Frontier Development Lab Exoplanets Day; Jun 28, 2018; San Jose, CA; United States
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  • 100
    Publication Date: 2019-07-13
    Description: AFRC (Armstrong Flight Research Center) has a long history, and a lot of lessons learned, in testing hypersonic structures. This poster describes hypersonic structures, how to test them, and the methods used to develop the testing.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: AFRC-E-DAA-TN60483 , Hypersonic Technology and Systems Conference (HTSC 2018); Aug 27, 2018 - Aug 30, 2018; Redondo Beach, CA; United States
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