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

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Approximations to the mean surface of Mars and Mars atmosphere using Mariner 9 occultations

When the Mariner 9 spacecraft passed behind Mars in its orbiting phase, the radio beam was cut off by some physical feature. These occultations occurred during the months of November and December 1971 and again in April and May 1972. The fairly good global spread of these data was used to estimate the shape of the Martian globe, as definable by mathematical shapes (ellipsoidal and spherical harmonic). The refraction profiles allowed the estimation of pressure near the occultation point; these, corrected back to an arbitrary fixed value of pressure, chosen to be 6.1 mb, were used as radii to an isobaric surface. Preliminary results showed a figure displacement from the mass center with a best fit southeast by 2.85 km. There was also an equatorial displacement in the direction of about 100 deg W. Atmospheric approximations for the mass center to 6.1-mb pressure distances were fit to an ellipsoid.

Cain, D. L.↗
NASA NTRS2000

Molecular and Higher Precision Isotopic Measurements of the Mars Atmosphere and Subsurface Volatiles

In response to the question 'what to do next' at Mars we explore the value of a high precision in situ measurement of isotopic and trace gas constituents in the atmosphere combined with a similar analysis of gas extracted from near surface rocks and soils. The scientific goals are to advance our understanding of the evolution of the Martian atmosphere and to search for fossils of past geochemical conditions. One element of this program that ties directly to the goals of the Astrobiology Program will be a sensitive search for simple or complex organic molecules contained in the atmosphere and in the solid phase. The broad chemical and isotopic analysis planned insures that a highly successful program will be carried out even if no organics are detected. We will demonstrate that the technology to carry out this Program is presently in hand.

Mahaffy, P. R.↗
NASA NTRS1999

Low-Power Temperature-Swing Adsorption for Mars Atmosphere Acquisition

The promise of In-Situ Resource Utilization (ISRU)-based mission architectures for Mars surface exploration will begin to be realized during the next decade as robotic spacecraft sent to Mars carry components and whole chemical plants for producing propellants from the planet's atmosphere. These chemical plants will need to perform three primary operations: acquisition of atmospheric carbon dioxide, reactions to transform the gas into oxygen and possibly fuel, and storage of the products. This presentation focuses on development of technologies at NASA Ames Research Center for the first of these operations, carbon dioxide acquisition.

Finn, J. E.↗
NASA NTRS2016

Mars Atmosphere Effects on Arc Welds: Phase 1

NASA has been unprecedented in achieving its goals related to space exploration and furthering the understanding of our solar system. In keeping with this trend, NASA's current mission is to land a team of astronauts on Mars and return them safely to Earth. In addition to comprising much of the structure and life support systems that will be brought to Mars for the habitat and vehicle, titanium and aluminum can be found and mined on Mars and may be used when building structures.Where metals are present, there will be a need for welding capabilities. For welds that need to be made quickly and are located far from heavy resistance or solid state welding machinery, there will be a need for basic arc welding. Arc welding has been a major cornerstone of manufacturing throughout the 20th century, and the portability and capability of gas tungsten arc welding (GTAW) will be necessary for repair, manufacturing, and survival on Mars. The two primary concerns for welding on Mars are that the Martian atmosphere contains high levels of carbon dioxide (CO2), and the atmospheric pressure is much lower than it is on Earth. The high levels of CO2 in the Martian atmosphere may dissociate and produce oxygen in the arc and therefore increase the risk of oxidation. For simplification, atmospheric pressure will not be taken into account for this experiment. For survival on Mars during this mission, the life support and water filtration systems must be kept operational at all times. In order to ensure that water filtration systems can be repaired in the event of an emergency, it is very important to have the capability to weld. The Orion capsule and Mars lander must also remain operational throughout the duration of the mission to ensure the safe return of the astronauts on the mission to Mars. A better understanding of welding in a Mars environment is important to ensure that repair welds are possible if the Orion capsule/Mars lander or water filtration system is damaged at any point while on the surface of Mars. The Orion capsule is made primarily of AA2219-T87, and the water filtration system is primarily Ti-6Al-4V, so the effect of the Mars environment on welding those materials must be known to reduce potential mission risk. GTAW is a portable process that can weld a versatile group of metals, so it has many potential applications for welding on Mars. Thus, missions to colonize Mars will depend on the capability to weld a strong, leak-tight joint. Metals are also likely to be used in support structures made of a lightweight and durable material. For this reason, it is important to understand the implications of welding in a Mars environment. A comparison of the Martian and terrestrial atmospheres are provided in table 1. Based on the elemental compositions, simulation of the Martian atmosphere can be made using primarily CO2 gas.

Courtright, Z. S.↗
NASA NTRS2005

Mars Atmospheric Chemistry in Electrified Dust Devils and Storms

Laboratory studies, simulations and desert field tests all indicate that aeolian mixing dust can generate electricity via contact electrification or "triboelectricity". In convective structures like dust devils or storms, grain stratification (or charge separation) occurs giving rise to an overall electric dipole moment to the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous simulation studies [1] indicate that this storm electric field on Mars can approach atmospheric breakdown field strength of 20 kV/m. In terrestrial dust devils, coherent dipolar electric fields exceeding 20 kV/m have been measured directly via electric field instrumentation. Given the expected electrostatic fields in Martian dust devils and storms, electrons in the low pressure CO2 gas can be energized via the electric field to values exceeding the electron dissociative attachment energy of both CO2 and H2O, resulting in the formation of new chemical products CO and O- and OH and H- within the storm. Using a collisional plasma physics model we present a calculation of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with ambient electric field, with substantial production of dissociative products when fields approach breakdown levels of 20-30 kV/m.

Farrell, W. M.↗
NASA NTRS1979

Mars atmospheric phenomena during major dust storms, as measured at surface

Meteorological instrumentation aboard the Viking Mars Landers measures wind, temperature, and pressure. Two global dust storms occurred during northern autumn and winter, observed both by the orbiters and by the landers. The meteorological data from the landers has been analyzed for the period just before first storm arrival to just after second storm arrival, with the objectives of defining the meteorological phenomena during the storm period, determining those associated with storm and dust arrival, and evaluating the effects on synoptic conditions and the general circulation. Times of dust arrival over the sites could be defined fairly closely from optical and pressure (solar tide) data, and dust arrival was also accompanied by changes in diurnal temperature range, temperature maxima, and temperature minima. The arrivals of the storms at Viking Lander 1 were accompanied by significant increases in wind speed and pressure. No such changes were observed at Viking Lander 2. It is possible that surface material could have been raised locally at Viking Lander 1. Throughout the period except for the time following the second dust storm the synoptic picture at Viking Lander 2 was one of eastward moving cyclonic and anticyclonic systems. These disappeared following the second storm, a phenomenon which may be related to the storm.

Ryan, J. A.↗
NASA NTRS1980

Mars atmosphere pressure periodicities from Viking observations

The first Martian year of pressure data taken by the Viking landers on Mars is subjected to power spectrum analysis. The analysis suggests that strong periodicities are present in the Martian atmosphere, especially at the high-latitude (48 deg N) site of the second lander. Most of these periodicities are probably due to the passage of baroclinic waves. Inspection of individual segments of data shows that the periodicities of the dominant waves vary significantly with time of year. This may be related to the amount of dust in the atmosphere since the dominant frequencies of the waves during times of major dust storms are quite different than at other times.

Sharman, R. D.↗
NASA NTRS2005

Bacillus subtilis spore survival and expression of germination-induced bioluminescence after prolonged incubation under simulated Mars atmospheric pressure and composition: implications for planetary protection and lithopanspermia

Bacterial endospores in the genus Bacillus are considered good models for studying interplanetary transfer of microbes by natural or human processes. Although spore survival during transfer itself has been the subject of considerable study, the fate of spores in extraterrestrial environments has received less attention. In this report we subjected spores of a strain of Bacillus subtilis, containing luciferase resulting from expression of an sspB-luxAB gene fusion, to simulated martian atmospheric pressure (7-18 mbar) and composition (100% CO(2)) for up to 19 days in a Mars simulation chamber. We report here that survival was similar between spores exposed to Earth conditions and spores exposed up to 19 days to simulated martian conditions. However, germination-induced bioluminescence was lower in spores exposed to simulated martian atmosphere, which suggests sublethal impairment of some endogenous spore germination processes.

Mars↗
NASA NTRS2014

Mars Atmospheric Composition, Isotope Ratios and Seasonal Variations: Overview and Updates of the SAM Measurements at Gale Crater

We will summarize the in situ measurements of atmospheric composition and the isotopic ratios of D/H in water, C-13/C-12, O-18/O-16, O-17 / O-16, and C-13 O-18 / C-12 O-16 in carbon dioxide, and Ar-38 / Ar-36, Kr-x / Kr-84, and N-15 / N-14 made in the martian atmosphere at Gale Crater from the Curiosity Rover using the Sample Analysis at Mars (SAM)'s Quadrupole Mass Spectrometer (QMS) and Tunable Laser Spectrometer (TLS). With data over 700 sols since the Curiosity landing, we will discuss evidence and implications for changes on seasonal and other timescales. We will also present results for continued methane and methane enrichment experiments over this time period. Comparison between our measurements in the modern atmosphere and those of martian meteorites like ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established approximately 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

Niles, Paul↗
NASA NTRS1979

A history of Mars atmospheric opacity in the southern hemisphere during the Viking extended mission

A history of developing opacity in the Mars southern hemisphere during the Viking extended mission has been compiled using orbiter images obtained at high altitude. Observations of changing contrasts under similar viewing conditions have been modeled by multiple-scattering intensity transfer equations that have produced a temporal description of changes in optical depth and particle-scattering properties within a network of control points. The results are presented in the form of Mercator and perspective plots for various dates.

Thorpe, T. E.↗
NASA NTRS2001

Thermal Emission Spectrometer Results: Mars Atmospheric Thermal Structure and Aerosol Distribution

Infrared spectra returned by the Thermal Emission Spectrometer (TES) are well suited for retrieval of the thermal structure and the distribution of aerosols in the Martian atmosphere. Combined nadir- and limb-viewing spectra allow global monitoring of the atmosphere up to 0.01 mbar (65 km). We report here on the atmospheric thermal structure and the distribution of aerosols as observed thus far during the mapping phase of the Mars Global Surveyor mission. Zonal and temporal mean cross sections are used to examine the seasonal evolution of atmospheric temperatures and zonal winds during a period extending from northern hemisphere mid-summer through vernal equinox (L(sub s) = 104-360 deg). Temperature maps at selected pressure levels provide a characterization of planetary-scale waves. Retrieved atmospheric infrared dust opacity maps show the formation and evolution of regional dust storms during southern hemisphere summer. Response of the atmospheric thermal structure to the changing dust loading is observed. Maps of water-ice clouds as viewed in the thermal infrared are presented along with seasonal trends of infrared water-ice opacity. Uses of these observations for diagnostic studies of the dynamics of the atmosphere are discussed.

Smith, Michael D.↗
NASA NTRS1989

Observations of the J = 1-0 CO lines in the Mars atmosphere - Radiodetection of C-13O and monitoring of C-12O

The high-resolution records obtained from mm-wave observations of the Mars J = 1-0 C-12O line and the radiodetection of C-13O in September-October 1986 and January 1987 have demonstrated mm-wave observations' utility in the study of planetary atmospheres. The results obtained allow the derivation of the Martian thermal profile at the time of dust-storms, and well as the monitoring of possible short-term changes in CO abundance. It is concluded that the observed C-12O/C-13O ratio is terrestrial, and that strong indications emerge of temporal variations in the thermal profile and CO abundance of Mars.

Lellouch, E.↗
NASA NTRS2016

Plasma Observations During the Mars Atmospheric Plume Event of March-April 2012

We present initial analysis and conclusions from plasma observations made during the reported Mars Dust plume event of March - April 2012. During this period, multiple independent amateur observers detected a localized, high-altitude plume over the Martian dawn terminator [Sanchez-Lavega7 et al., Nature, 2015, doi:10.1038nature14162], the origin of which remains to be explained. We report on in-situ measurements of ionospheric plasma density and solar wind parameters throughout this interval made by Mars Express, obtained over the surface region, but at the opposing terminator. We tentatively conclude that the formation and/or transport of this plume to the altitudes where it was observed could be due in part the result of a large interplanetary coronal mass ejection (ICME) encountering the Martian system. Interestingly, we note that a similar plume detection in May 1997 may also have been associated with a large ICME impact at Mars.

Plumes↗
NASA NTRS1993

Escape of Mars atmospheric carbon through time by photochemical means

Luhmann et al. recently suggested that sputtering of the Martian atmosphere by re-entering O(+) pickup ions could have provided a significant route of escape for CO2 and its products throughout Mars' history. They estimated that the equivalent of C in an approximately 140-mbar CO2 atmosphere should have been lost this way if the Sun and solar wind evolved according to available models. Another source of escaping C (and O) that is potentially important is the dissociative recombination of ionospheric CO(+) near the exobase. We have evaluated the loss rates due to this process for 'ancient' solar EUV radiation fluxes of 1, 3, and 6 times the present flux in order to calculate the possible cumulative loss over the last 3.5 Gyr.

Luhmann, J. G.↗
NASA NTRS2016

Optimization of a Hot Structure Aeroshell and Nose Cap for Mars Atmospheric Entry

The National Aeronautics and Space Administration (NASA) is preparing to send humans beyond Low Earth Orbit and eventually to the surface of Mars. As part of the Evolvable Mars Campaign, different vehicle configurations are being designed and considered for delivering large payloads to the surface of Mars. Weight and packing volume are driving factors in the vehicle design, and the thermal protection system (TPS) for planetary entry is a technology area which can offer potential weight and volume savings. The feasibility and potential benefits of a ceramic matrix composite hot structure concept for different vehicle configurations are explored in this paper, including the nose cap for a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) and an aeroshell for a mid lift-to-drag (Mid L/D) concept. The TPS of a planetary entry vehicle is a critical component required to survive the severe aerodynamic heating environment during atmospheric en- try. The current state-of-the-art is an ablative material to protect the vehicle from the heat load. The ablator is bonded to an underlying structure, which carries the mechanical loads associated with entry. The alternative hot structure design utilizes an advanced carbon-carbon material system on the outer surface of the vehicle, which is exposed to the severe heating and acts as a load carrying structure. The preliminary design using the hot structure concept and the ablative concept is determined for the spherical nose cap of the HIAD entry vehicle and the aeroshell of the Mid L/D entry vehicle. The results of the study indicate that the use of hot structures for both vehicle concepts leads to a feasible design with potential weight and volume savings benefits over current state-of-the-art TPS technology that could enable future missions.

Langston, Sarah L.↗
NASA NTRS1993

Mars atmospheric dynamics as simulated by the NASA Ames General Circulation Model. II - Transient baroclinic eddies

A large set of experiments performed with the NASA Ames Mars General Circulation Model is analyzed to determine the properties, structure, and dynamics of the simulated transient baroclinic eddies. There is strong transient baroclinic eddy activity in the extratropics of the Northern Hemisphere during the northern autumn, winter, and spring seasons. The eddy activity remains strong for very large dust loadings, though it shifts northward. The eastward propagating eddies are characterized by zonal wavenumbers of 1-4 and periods of about 2-10 days. The properties of the GCM baroclinic eddies in the northern extratropics are compared in detail with analogous properties inferred from Viking Lander meteorology observations.

Barnes, Jeffrey R.↗
NASA NTRS1991

A new look at dust and clouds in the Mars atmosphere - Analysis of emission-phase-function sequences from global Viking IRTM observations

The present analysis of emission-phase function (EPF) observations from the IR thermal mapper aboard the Viking Orbiter encompasses polar latitudes, and Viking Lander sites, and spans a wide range of solar longitudes. A multiple scattering radiative transfer model which incorporates a bidirectional phase function for the surface and atmospheric scattering by dust and clouds yields surface albedos and dust and ice optical properties and optical depths for the variety of Mars conditions. It is possible to fit all analyzed EPF sequences corresponding to dust scattering with an albedo of 0.92, rather than the 0.86 given by Pollack et al. on the bases of Viking Lander observations.

Clancy, R. T.↗
NASA NTRS1982

Mars' atmospheric behavior from Viking infra-red thermal mapper measurements

Data from the 15 micron band of CO2 readings with the two Viking IR thermal mappers are discussed. Contrasts were observed to be strong between clear and dusty conditions, with a latitudinal gradient and a diurnal amplitude variation in the winter southern hemisphere. Consistency was found in zonal mean temperatures in the absence of dust, with a peak temperature of 180 K at the poles and a diurnal amplitude of 15 K at the equator. Large temperature increases occur in dusty conditions, with global dust storms being present in the northern, but not southern, hemisphere. Estimations of the surface and atmospheric temperatures are calculated in order to derive optical depths from the IR measurements of atmospheric opacity. The optical depth around the whole planet is found to be relatively uniform at any given moment. Finally, the diurnal behavior of the brightness temperature is outlined for 1.4 Mars years.

Martin, T. Z.↗