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Results for “PLANETARY ATMOSPHERES”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Origin and evolution of planetary and satellite atmospheres

The present volume on the origin and evolution of planet and satellite atmospheres discusses the chemistry of interstellar gas and grains, planetary accretion, cometary composition, the inventories of asteroid volatiles, key similarities and differences among the terrestrial planets' atmospheric compositions, and planets' atmospheric escape and water loss. Also discussed are planetary atmosphere-planetary interior evolutionary coupling, the atmospheric composition of the outer planets, the structure and composition of giant planet interiors, the tenuous atmosphere of Io, the sources of the atmospheres of the outer solar system's satellites, the present state and chemical evolution of the Titan, Triton, and Pluto atmospheres, and the thermal structure and heat balance of the outer planets.

Atreya, S. K.↗
NASA NTRS1985

Terrestrial Planets: Comparative Planetology

Papers were presented at the 47th Annual Meteoritical Society Meeting on the Comparative planetology of Terrestrial Planets. Subject matter explored concerning terrestrial planets includes: interrelationships among planets; plaentary evolution; planetary structure; planetary composition; planetary Atmospheres; noble gases in meteorites; and planetary magnetic fields.

Source record↗
NASA NTRS2013

Radio Science Measurements with Suppressed Carrier

Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

Cramer-Rao bound↗
NASA NTRS1967

Research and advanced concepts

Gaseous breakdown of simulated planetary atmospheres and illustration of Greenhouse effect, thermal radiation from ionized argon, liquid magnetohydrodynamic power conversion

GASEOUS DIFFUSION↗
NASA NTRS1977

Spectroscopic studies of very old hot stars. III - Atmospheric properties of seven planetary nuclei

The atmospheric properties of seven planetary nuclei which have O or Of-type spectra were determined by use of the Zanstra method and by analysis of the visual line spectra. One finding is that the O-type spectral sequence may extend to effective temperatures of 90,000 kelvins or more, if the results of the Zanstra method are to be believed. However, there are some indications of internal inconsistency in the Zanstra method and some outstanding discrepancies between the effective temperatures indicated by the Zanstra method and those indicated from analysis of the visual line spectra. Two ways to resolve these discrepancies are to postulate an excess of extreme-UV stellar flux or to postulate a hot binary companion for some central stars. In either case the validity of the Harmon-Seaton evolutionary sequence for central stars becomes questionable.

Heap, S. R.↗
DOE OSTI2020

Toward Complete Characterization: Prospects for Directly Imaging Transiting Exoplanets

High-contrast direct imaging of exoplanets can provide many important observables, including measurements of the orbit, spectra that probe the lower layers of the atmosphere, and phase variations of the planet, but cannot directly measure planet radius or mass. Our future understanding of directly imaged exoplanets will therefore rely on extrapolated models of planetary atmospheres and bulk composition, which need robust calibration. We estimate the population of extrasolar planets that could serve as calibrators for these models. Critically, this population of “standard planets” must be accessible to both direct imaging and the transit method, allowing for radius measurement. We show that the search volume of a direct imaging mission eventually overcomes the transit probability falloff with semimajor axis, so that as long as cold planets are not exceedingly rare, the population of transiting planets and directly imageable planets overlaps. Using current extrapolations of Kepler occurrence rates, we estimate that ∼8 standard planets could be characterized shortward of 800 nm with an ambitious future direct imaging mission like LUVOIR-A and several dozen could be detected at the V band. We show the design space that would expand the sample size and discuss the extent to which ground- and space-based surveys could detect this small but crucial population of planets.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1989

Theoretical studies of important processes in planetary and comet atmospheres. Renewel request

Current efforts have focused on the dissociative recombination (DR) of O2(+), a process of great importance in planetary atmospheres. This process is difficult to study experimentally because of the need to determine the dependence of the product electronic states and kinetic energies upon the vibrational distribution of the ion and electron temperature. The knowledge of these characteristics of DR is needed to accurately model planetary ionospheres. Using a theoretical quantum chemical approach, the generation of O(1S) from DR was studied in detail.

Guberman, Steven L.↗
NASA NTRS1977

Solar wind sputtering of the Martian atmosphere

The interaction between the solar wind and a planetary atmosphere is evaluated as a cause of atmospheric mass loss. For the case of Mars, calculations suggest that an amount of material has been sputtered which is of the same order as the mass of the present atmosphere.

Haff, P. K.↗
NASA NTRSDate not supplied

Upgrades to the Mars Global Reference Atmospheric Model (Mars-GRAM)

The inability to test planetary spacecraft in the flight environment prior to a mission requires engineers to rely on ground-based testing and models of the vehicle and expected environments. One of the most widely used engineering reference models of planetary atmospheres are the Global Reference Atmospheric Models (GRAMs). The NASA Science Mission Directorate (SMD) has provided funding support to upgrade the GRAMs since Fiscal Year 2018. The GRAM upgrades are being developed by NASA Marshall Space Flight Center and NASA Langley Research Center. This poster provides details regarding recent MarsGRAM upgrades.

atmospheric models↗
NASA NTRS1964

Re-entry.

Reentry vehicle configuration for lift trajectory control and minimum heating during planetary atmosphere entry

REENTRY EFFECT↗
NASA NTRS2016

Detection of H2O and Evidence for TiO VO in an Ultra Hot Exoplanet Atmosphere.

We present a primary transit observation for the ultra-hot (Teq approx. 2400 K) gas giant expolanet WASP-121b, made using the Hubble Space Telescope Wide Field Camera 3 in spectroscopic mode across the 1.12-1.64 micron wavelength range. The 1.4 microns water absorption band is detected at high confidence (5.4(sigma)) in the planetary atmosphere. We also reanalyze ground-based photometric light curves taken in the B, r′, and z′ filters. Significantly deeper transits are measured in these optical bandpasses relative to the near-infrared wavelengths. We conclude that scattering by high-altitude haze alone is unlikely to account for this difference and instead interpret it as evidence for titanium oxide and vanadium oxide absorption. Enhanced opacity is also inferred across the 1.12-1.3 micron wavelength range, possibly due to iron hydride absorption. If confirmed, WASP-121b will be the first exoplanet with titanium oxide, vanadium oxide, and iron hydride detected in transmission. The latter are important species in M/L dwarfs and their presence is likely to have a significant effect on the overall physics and chemistry of the atmosphere, including the production of a strong thermal inversion.

Spectroscopy↗
NASA NTRS2017

Extratropical Weather Systems on Mars: Radiatively-Active Water Ice Effects

Extratropical, large-scale weather disturbances, namely transient, synoptic-period,baroclinic barotropic eddies - or - low- (high-) pressure cyclones (anticyclones), are components fundamental to global circulation patterns for rapidly rotating, differentially heated, shallow atmospheres such as Earth and Mars. Such "wave-like" disturbances that arise via (geophysical) fluid shear instability develop, mature and decay, and travel west-to-east in the middle and high latitudes within terrestrial-like planetary atmospheres. These disturbances serve as critical agents in the transport of heat and momentum between low and high latitudes of the planet. Moreover, they transport trace species within the atmosphere (e.g., water vapor/ice, other aerosols (dust), chemical species, etc). Between early autumn through early spring, middle and high latitudes on Mars exhibit strong equator-to-pole mean temperature contrasts (i.e., "baroclinicity"). Data collected during the Viking era and observations from both the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) indicate that such strong baroclinicity supports vigorous, large-scale eastward traveling weather systems [Banfield et al., 2004; Barnes et al., 1993]. A good example of traveling weather systems, frontal wave activity and sequestered dust activity from MGS/MOC image analyses is provided in Figure 1 (cf. Wang et al. [2005]). Utilizing an upgraded and evolving version of the NASA Ames Research Center (ARC) Mars global climate model, investigated here are key dynamical and physical aspects of simulated northern hemisphere (NH) large-scale extratropica lweather systems,with and without radiatively-active water ice clouds. Mars Climate Model:

cyclones↗