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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Performance Modeling of an Airborne Raman Water Vapor Lidar

A sophisticated Raman lidar numerical model had been developed. The model has been used to simulate the performance of two ground-based Raman water vapor lidar systems. After tuning the model using these ground-based measurements, the model is used to simulate the water vapor measurement capability of an airborne Raman lidar under both day-and night-time conditions for a wide range of water vapor conditions. The results indicate that, under many circumstances, the daytime measurements possess comparable resolution to an existing airborne differential absorption water vapor lidar while the nighttime measurement have higher resolution. In addition, a Raman lidar is capable of measurements not possible using a differential absorption system.

Whiteman, D. N.↗
NASA NTRS1977

Computational design of the basic dynamical processes of the UCLA general circulation model

The 12-layer UCLA general circulation model encompassing troposphere and stratosphere (and superjacent 'sponge layer') is described. Prognostic variables are: surface pressure, horizontal velocity, temperature, water vapor and ozone in each layer, planetary boundary layer (PBL) depth, temperature, moisture and momentum discontinuities at PBL top, ground temperature and water storage, and mass of snow on ground. Selection of space finite-difference schemes for homogeneous incompressible flow, with/without a free surface, nonlinear two-dimensional nondivergent flow, enstrophy conserving schemes, momentum advection schemes, vertical and horizontal difference schemes, and time differencing schemes are discussed.

Arakawa, A.↗
NASA NTRS1982

Ground-based lidar measurements of ozone, water vapor and aerosols in the lower stratosphere and troposphere

Lidar measurements of ozone and water vapor concentrations were performed during several field experiments in 1980-1981 by means of the differential absorption laser technique. Profiles up to 26 km for ozone and up to 9 km for water vapor are presented. Also, a lidar survey of aerosol layers ranging from 12 to 23 km were performed following the Mt. St. Helens major eruption (May 1980). Experiments were conducted at the CNRS lidar facility of the Haute Provence Observatory which is located in southern France (44 deg N, 5 deg E). For ozone a vertical profile is recorded in three sequences, each requiring 15 min of acquisition time. The relative accuracy is better than 5 percent at the lower altitude and falls to 20 percent at 25 km. For water vapor the time sequences are 4 min or 8 min long and the accuracy is better than 10 percent in the lower troposphere.

Flamant, P. H.↗
NASA NTRSDate not supplied

History, Current Operations and Management of Water Systems on the International Space Station

In November 2000, the Expedition 1 crew to the International Space Station (ISS) arrived onboard, thus beginning a 19+ year need to provide potable water to the crew, as well as water to key life support systems. For the first 8 years of ISS operations, the water systems' operations were relatively simple. It consisted of manifesting water via cargo ships or generated via the Space Shuttle fuel cells and stored on ISS to supplement the water processing systems on the Russian segment of the ISS. In 2008, the Water Processor Assembly (WPA), Urine Processor Assembly (UPA), along with a U.S. provided toilet arrived onboard, supplementing the Oxygen Generator Assembly (OGA). This new equipment, known as Regen ECLSS (Regenerative Environmental Control and Life Support Systems), provided a significant capability in recycling fluid within the ISS and minimized manifestation needs. Early in the operations of the Regen ECLSS system, it became clear that the tank capacities were under sized. This led to excessive use of costly crew time to perform water operations. In 2012, a group of ISS flight controllers and engineers proposed and developed a new system that would provide integrated water tanks that could be fully operated from Mission Control on the ground to move water around within the systems. This system has very recently been installed on the ISS and commissioning operations have occurred. This paper will provide a general history of water operations on the ISS, as new systems arrived, and new operations were required. Challenges with water balance, to both avoid overfilling the system as well as avoid running out of water, will be discussed, along with touching on the convoluted steps the Flight Control team had to perform daily to predict future water needs. Finally, the new water storage system will be discussed and the benefits it brings to ISS water operations.

Christopher A Brown↗
NASA NTRS2003

Thermal Modeling of Permafrost Melt by Overlying Lava Flows with Applications to Flow-associated Outflow Channel Volumes in the Cerberus Plains, Mars

The Cerberus region of Mars has numerous geologically recent fluvial and volcanic features superimposed spatially, with some of them using the same flow channels and apparent vent structures. Lava-water interaction landforms such as psuedocraters suggest some interaction of emplacing lava flows with underlying ground ice or water. This study investigates a related interaction type a region where the emplaced lava might have melted underlying ice in the regolith, as there are small outflow channel networks emerging from the flank flows of a lava shield over a portion of the Eastern Cerberus Rupes. Specifically, we use high-resolution Mars Orbiter Laser Altimeter (MOLA) topography to constrain channel and flow dimensions, and thus estimate the thermal pulse from the emplaced lava into the substrate and the resulting melting durations and refreezing intervals. These preliminary thermal models indicate that the observed flows could easily create thermal pulse(s) sufficient to melt enough ground ice to fill the observed fluvial small outflow channels. Depending on flow eruption timing and hydraulic recharge times, this system could easily have produced multiple thermal pulses and fluvial releases. This specific case suggests that regional small water releases from similar cases may be more common than suspected, and that there is a possibility for future fluvial releases if ground ices are currently present and future volcanic eruptions in this young region are possible.

Chase, Z. A. J.↗
NASA NTRS1987

Measurements of mesospheric water vapor in 1984 and 1985 - Results and implications for middle atmospheric transport

The detailed results of ground-based mesospheric water vapor measurements obtained by microwave spectroscopy at the Jet Propulsion Laboratory (JPL) from December 1984 to April 1985 (JPL 1984/85), and an overview of results obtained the previous year from April to June 1984 are presented. The JPL 1984/85 spectral data appeared to contain an instrumental baseline curvature which was bracketed and removed. In general, the JPL 1984/85 results are in good agreement with those of previous measurements. They indicate water vapor mixing ratios between 6 and 8 ppmv at 60 or 65 km and falling off steeply with height above this point to values of less than 2 ppmv at 80 km. In addition, there is a large amount of day-to-day variability indicated in the data. A major result of the study is that it is found that both the observed vertical gradient of water vapor mixing ratio and its seasonal variation are consistent with the hypothesis that vertical transport time scales are smaller, perhaps by an order of magnitude, than values currently used in both one- and two-dimensional photochemical/dynamical models.

Bevilacqua, Richard M.↗
NASA NTRS2010

Chemical Analysis Results for Potable Water from ISS Expeditions 21 to 25

The Johnson Space Center Water and Food Analytical Laboratory (WAFAL) performed detailed ground-based analyses of archival water samples for verification of the chemical quality of the International Space Station (ISS) potable water supplies for Expeditions 21 to 25. Over a 14-month period, the Space Shuttle visited the ISS on five occasions to complete construction and deliver supplies. The onboard supplies of potable water available for consumption by the Expeditions 21 to 25 crews consisted of Russian ground-supplied potable water, Russian potable water regenerated from humidity condensate, and US potable water recovered from urine distillate and condensate. Chemical archival water samples that were collected with U.S. hardware during Expeditions 21 to 25 were returned on Shuttle flights STS-129 (ULF3), STS-130 (20A), STS-131 (19A), STS-132 (ULF4) and STS-133 (ULF5), as well as on Soyuz flights 19-22. This paper reports the analytical results for the returned archival water samples and evaluates their compliance with ISS water quality standards. The WAFAL also received and analyzed aliquots of some Russian potable water samples collected in-flight and pre-flight samples of Rodnik potable water delivered to the Station on the Russian Progress vehicle during Expeditions 21 to 25. These additional analytical results are also reported and discussed in this paper.

Straub, John E., II↗
NASA NTRS2011

Chemical Analysis Results for Potable Water from ISS Expeditions 21 Through 25

The Johnson Space Center Water and Food Analytical Laboratory (WAFAL) performed detailed ground-based analyses of archival water samples for verification of the chemical quality of the International Space Station (ISS) potable water supplies for Expeditions 21 through 25. Over a 14-month period the Space Shuttle visited the ISS on four occasions to complete construction and deliver supplies. The onboard supplies of potable water available for consumption by the Expeditions 21 to 25 crews consisted of Russian ground-supplied potable water, Russian potable water regenerated from humidity condensate, and US potable water recovered from urine distillate and condensate. Chemical archival water samples that were collected with U.S. hardware during Expeditions 21 to 25 were returned on Shuttle flights STS-129 (ULF3), STS-130 (20A), STS-131 (19A), and STS-132 (ULF4), as well as on Soyuz flights 19-23. This paper reports the analytical results for these returned potable water archival samples and their compliance with ISS water quality standards.

Straub, John E., II↗
NASA NTRS1990

The role of water ice clouds in the Martian hydrologic cycle

A one-dimensional model for the seasonal cycle of water on Mars has been used to investigate the direction of the net annual transport of water on the planet and to study the possible role of water ice clouds, which are included as an independent phase in addition to ground ice and water vapor, in the cycle. The calculated seasonal and spatial patterns of occurrence of water ice clouds are qualitatively similar to the observed polar hoods, suggesting that these polar clouds are, in fact, an important component of water cycle. A residual dry ice in the south acts as a cold trap which, in the absence of sources other than the caps, will ultimately attract the water ice from the north cap; however, in the presence of a source of water in northern midlatitudes during spring, it is possible that the observed distribution of vapor and ice can be in a steady state even if a residual CO2 cap is a permanent feature of the system.

James, Philip B.↗
NASA NTRS1993

Thermal Analyzer for Planetary Soil (TAPS): an in Situ Instrument for Mineral and Volatile-element Measurements

Thermal Analyzer for Planetary Soil (TAPS) offers a specific implementation for the generic thermal analyzer/evolved-gas analyzer (TA/EGA) function included in the Mars Environmental Survey (MESUR) strawman payload; applications to asteroids and comets are also possible. The baseline TAPS is a single-sample differential scanning calorimeter (DSC), backed by a capacitive-polymer humidity sensor, with an integrated sampling mechanism. After placement on a planetary surface, TAPS acquires 10-50 mg of soil or sediment and heats the sample from ambient temperature to 1000-1300 K. During heating, DSC data are taken for the solid and evolved gases are swept past the water sensor. Through ground based data analysis, multicomponent DSC data are deconvolved and correlated with the water release profile to quantitatively determine the types and relative proportions of volatile-bearing minerals such as clays and other hydrates, carbonates, and nitrates. The rapid-response humidity sensors also achieve quantitative analysis of total water. After conclusion of soil-analysis operations, the humidity sensors become available for meteorology. The baseline design fits within a circular-cylindrical volume less than 1000 cm(sup 3), occupies 1.2 kg mass, and consumes about 2 Whr of power per analysis. Enhanced designs would acquire and analyze multiple samples and employ additional microchemical sensors for analysis of CO2, SO2, NO(x), and other gaseous species. Atmospheric pumps are also being considered as alternatives to pressurized purge gas.

Gooding, J. L.↗
NASA NTRS2004

Starting Conditions for Hydrothermal Systems Underneath Martian Craters: Hydrocode Modeling

Mars is the most Earth-like of the Solar System s planets, and the first place to look for any sign of present or past extraterrestrial life. Its surface shows many features indicative of the presence of surface and sub-surface water, while impact cratering and volcanism have provided temporary and local surface heat sources throughout Mars geologic history. Impact craters are widely used ubiquitous indicators for the presence of sub-surface water or ice on Mars. In particular, the presence of significant amounts of ground ice or water would cause impact-induced hydrothermal alteration at Martian impact sites. The realization that hydrothermal systems are possible sites for the origin and early evolution of life on Earth has given rise to the hypothesis that hydrothermal systems may have had the same role on Mars. Rough estimates of the heat generated in impact events have been based on scaling relations, or thermal data based on terrestrial impacts on crystalline basements. Preliminary studies also suggest that melt sheets and target uplift are equally important heat sources for the development of a hydrothermal system, while its lifetime depends on the volume and cooling rate of the heat source, as well as the permeability of the host rocks. We present initial results of two-dimensional (2D) and three-dimensional (3D) simulations of impacts on Mars aimed at constraining the initial conditions for modeling the onset and evolution of a hydrothermal system on the red planet. Simulations of the early stages of impact cratering provide an estimate of the amount of shock melting and the pressure-temperature distribution in the target caused by various impacts on the Martian surface. Modeling of the late stage of crater collapse is necessary to characterize the final thermal state of the target, including crater uplift, and distribution of the heated target material (including the melt pool) and hot ejecta around the crater.

Pierazzo, E.↗
NASA NTRS1976

Diurnal behaviour of water on Mars

A numerical model of the diurnal transport of water across the Martian surface is developed. The atmospheric boundary layer is modeled in terms of local radiative-convective processes, and radiative effects of ice fogs near the surface are included. Diffusion of water in the ground is treated for the cases of adsorption and condensation. The model is applied to the diurnal variation of water vapor in the atmosphere as observed by Barker (1974). The morning rise in the amount of water vapor can be explained in terms of the evaporation of ground fogs. The evening decrease is compatible with the model if adsorption dominates in the soil. The average level of vapor concentration requires that the atmosphere above the boundary layer be relatively dry. The ground fogs persist until midmorning and should be observable. Some consequences of these conclusions are discussed.

Flasar, F. M.↗
DOE OSTI2022

Geologic Disposal Safety Assessment (GDSA) Biosphere Model Development

The Spent Fuel and Waste Science and Technology Campaign of the U.S. Department of Energy Office of Nuclear Energy, Office of Spent Fuel and Waste Disposition is conducting research and development on geologic disposal of spent nuclear fuel and high-level nuclear waste. This work includes the Geologic Disposal Safety Assessment (GDSA) program which is charged with development of generic deep geologic repository concepts and system performance assessment models. One part of the GDSA framework is the development of a biosphere model capable of assessing doses to potential receptors exposed to radionuclides released from geologic disposal sites. As part of the GDSA framework, a biosphere model compatible with the PFLOTRAN massively parallel subsurface flow and reactive transport code is under development. The PFLOTRAN model provides the radionuclide source term for the biosphere model. The GDSA Biosphere model then assesses the potential movement of radionuclides through the surface biosphere and the subsequent exposure to a human receptor living in the biosphere. The biosphere model includes pathways originating from the groundwater as well as pathways originating from surface water bodies that have a water exchange with a contaminated groundwater body. The pathways for human exposure include consumption of drinking water, irrigated crops, meat animals, aquatic vegetation, and animals, etc.; external exposure from irrigated ground surfaces, surface water bodies, recreational activities, etc.; and inadvertent exposures such as ingestion of contaminated soils or shower water, etc. The GDSA Biosphere model was designed to be flexible and generic in order to accommodate a variety of different sites and climate states. This presentation will present the on the purpose, design, and development progress of the GDSA Biosphere Model.

GDSA, biosphere, repository↗
NASA NTRS2000

Orbital SAR and Ground-Penetrating Radar for Mars: Complementary Tools in the Search for Water

The physical structure and compositional variability of the upper martian crust is poorly understood. Optical and infrared measurements probe at most the top few cm of the surface layer and indicate the presence of layered volcanics and sediments, but it is likely that permafrost, hydrothermal deposits, and transient liquid water pockets occur at depths of meters to kilometers within the crust. An orbital synthetic aperture radar (SAR) can provide constraints on surface roughness, the depth of fine-grained aeolian or volcanic deposits, and the presence of strongly absorbing near-surface deposits such as carbonates. This information is crucial to the successful landing and operation of any rover designed to search for subsurface water. A rover-based ground-penetrating radar (GPR) can reveal layering in the upper crust, the presence of erosional or other subsurface horizons, depth to a permafrost layer, and direct detection of near-surface transient liquid water. We detail here the radar design parameters likely to provide the best information for Mars, based on experience with SAR and GPR in analogous terrestrial or planetary environments.

Campbell, B. A.↗
NASA NTRS1979

Solar heating and hot water system installed at Cherry Hill, New Jersey

The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

Source record↗
NASA NTRS1993

Equatorial ground ice on Mars: Steady-state stability

Current Martian equatorial surface temperatures are too warm for water ice to exist at the surface for any appreciable length of time before subliming into the atmosphere. Subsurface temperatures are generally warmer still and, despite the presence of a diffusive barrier of porous regolith material, it has been shown by Smoluchowski, Clifford and Hillel, and Fanale et al. that buried ground ice will also sublime and be lost to the atmosphere in a relatively short time. We investigate the behavior of this subliming subsurface ice and show that it is possible for ice to maintain at a steady-state depth, where sublimation and diffusive loss to the atmosphere is balanced by resupply from beneath by diffusion and recondensation of either a deeper buried ice deposits or ground water. We examine the behavior of equatorial ground ice with a numercial time-marching molecular diffusion model. In our model we allow for diffusion of water vapor through a porous regolith, variations in diffusivity and porosity with ice content, and recondensation of sublimed water vapor. A regolith containing considerable amounts of ice can still be very porous, allowing water vapor to diffuse up from deeper within the ice layer where temperatures are warmer due to the geothermal gradient. This vapor can then recondense nearer to the surface where ice had previously sublimed and been lost to the atmosphere. As a result we find that ice deposits migrate to find a steady-state depth, which represents a balance between diffusive loss to the atmosphere through the overlying porous regolith and diffusive resupply through a porous icy regolith below. This depth depends primarily on the long-term mean surface temperature and the nature of the geothermal gradient, and is independent of the ice-free porosity and the regolith diffusivity. Only the rate of loss of ground ice depends on diffusive properties.

Mellon, Michael T.↗
NASA NTRS1997

West-Antarctic Ice Streams: Analog to Ice Flow in Channels on Mars

Sounding of the sea floor in front of the Ross Ice Shelf in Antarctica recently revealed large persistent patterns of longitudinal megaflutes and drumlinoid forms, which are interpreted to have formed at the base of ice streams during the list glacial advance. The flutes bear remarkable resemblance to longitudinal grooves and highly elongated streamlined islands found on the floors of some large martian channels, called outflow channels. ln addition, other similarities exist between Antarctic ice streams and outflow channels. Ice streams are 30 to 80 km wide and hundreds of kilometers long, as are the martian channels. Ice stream beds are below sea level. Floors of many martian outflow channels lie below martian datum, which may have been close to or below past martian sea levels. The Antarctic ice stream bed gradient is flat and locally may go uphill, and surface slopes are exceptionally low. So are gradients of martian channels. The depth to the bed in ice streams is 1 to 1.5 km. At bankful stage, the depth of the fluid in outflow channels would have been 1 to 2 km. These similarities suggest that the martian outflow channels, whose origin is commonly attributed to gigantic catastrophic floods, were locally filled by ice that left a conspicuous morphologic imprint. Unlike the West-Antarctic-ice streams, which discharge ice from an ice sheet, ice in the martian channels came from water erupting from the ground. In the cold martian environment, this water, if of moderate volume, would eventually freeze. Thus it may have formed icings on springs, ice dams and jams on constrictions in the channel path, or frozen pools. Given sufficient thickness and downhill surface gradient, these ice masses would have moved; and given the right conditions, they could have moved like Antarctic ice streams.

Lucchitta, B. K.↗
NASA NTRS1994

Fluid-loading solutions and plasma volume: Astro-ade and salt tablets with water

Fluid loading with salt and water is a countermeasure used after space flight to restore body fluids. However, gastrointestinal side effects have been frequently reported in persons taking similar quantities of salt and water in ground-based studies. The effectiveness of the Shuttle fluid-loading countermeasure (8 gms salt, 0.97 liters of water) was compared to Astro-ade (an isotonic electrolyte solution), to maintain plasma volume (PV) during 4.5 hrs of resting fluid restriction. Three groups of healthy men (n=6) were studied: a Control Group (no drinking), an Astro-ade Group, and a Salt Tablet Group. Changes in PV after drinking were calculated from hematocrit and hemoglobin values. Both the Salt Tablet and Astro-ade Groups maintained PV at 2-3 hours after ingestion compared to the Control Group, which had a 6 percent decline. Side effects (thirst, stomach cramping, and diarrhea) were noted in at least one subject in both the Astro-ade and Salt Tablet Groups. Nausea and vomiting were reported in one subject in the Salt Tablet Group. It was concluded that Astro-ade may be offered as an alternate fluid-loading countermeasure but further work is needed to develop a solution that is more palatable and has fewer side effects.

Fortney, Suzanne M.↗