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NASA NTRS2012

Energy Balance Models and Planetary Dynamics

We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.

Domagal-Goldman, Shawn↗
NASA NTRS2012

Sources of Sulfate Found in Mounds and Lakes at the Lewis Cliffs Ice Tongue, Transantarctic

Massive but highly localized Na-sulfate mounds (mirabilite, Na2SO4.10H2O) have been found at the terminal moraine of the Lewis Cliffs Ice Tongue (LCIT), Antarctica. (Sigma)34S and (Sigma)18O values of LCIT mirabilite range from +48.8 to +49.3% (CDT), and -16.6 to -17.1% (V-SMOW), respectively, while (Delta)17O average -0.37% (V-SMOW). LCIT mirabilite mounds are isotopically different from other mirabilite mounds found in coastal regions of Antarctica, which have isotope values close to seawater compositions. (Sigma)18O and (Delta)17O values suggest the incorporation of isotopically light glacial water. Data point to initial sulfate formation in an anoxic water body, either as a stratified anoxic deep lake on the surface, a sub-glacial water reservoir, or a sub-glacial lake. Several surface lakes of varying size are also present within this region of the LCIT, and in some cases are adjacent to the mirabilite mounds. O and D isotope compositions of surface lakes confirm they are derived from a mixture of glacial ice and snow that underwent moderate evaporation. (Sigma)18O and (Sigma)D (V-SMOW) values of snow, ice, and lake water range from -64.2 to -29.7%, and -456.0 to -231.7%, respectively. However, the isotope chemistry of these surface lakes is extremely different from the mounds. Dissolved SO4-2 (Sigma)34S and (Sigma)18O values range from +12.0 to +20.0% and -12.8 to -22.2% (the most negative (Sigma)18O of terrestrial sulfate ever reported), respectively, with sulfate (Delta)17O ranging from +0.93 to 2.24%. Ion chromatography data show that lake water is fresh to brackish in origin, with TDS less than 1500 ppm, and sulfate concentration less than 431 ppm. Isotope and chemical data suggest that these lakes are unlikely the source of the mirabilite mounds. We suggest that lake water sulfate is potentially composed of a mixture of atmospheric sulfate and minor components of sulfate of weathering origin, much like the sulfate in the polar plateau soils of the McMurdo Dry Valleys. A simple model explains mirabilite mound formation at the LCIT. Sulfur redox processes could occur sub-glacially as a result of liquid-water-based glacial conditions (Alpine style glacier), most likely formed by pressure melting of overlying ice (Aharon, GCA, 52, 2321-2331). We suggest that the aqueous base of the LCIT contains dissolved SO42- and is anoxic where sulfate reduction to H2S, HS-, or native sulfur takes place. Sulfide is removed by either precipitation as sulfide minerals or by escape of H2S (neither of which have been observed). Mirabilite precipitation is likely the result of evaporation or freezing of sulfate-rich brines as they reach the surface where they manifest themselves as mounds. Pressure from the overlying ice contributing to a pressure-melting scenario that creates the sub-glacial aqueous environment also contributes to the mechanism of upward transport of the sulfate-rich fluids. Further evidence to support this upward transport model comes from the nature of ice motion at the LCIT. Cassidy et al (Meteoritics, 27, 490-525, 1992) pointed out that it is the vertical ice motion in this area that creates the meteorite-stranding surface that could also account for upward transport of sulfate-rich fluids. Alternatively, mirabilite was deposited in a similar condition as present-day coastal Antarctica when the LCIT was wetter and warmer

Socki, Richard↗
NASA NTRS2013

Airborne Tomographic Swath Ice Sounding Processing System

Glaciers and ice sheets modulate global sea level by storing water deposited as snow on the surface, and discharging water back into the ocean through melting. Their physical state can be characterized in terms of their mass balance and dynamics. To estimate the current ice mass balance, and to predict future changes in the motion of the Greenland and Antarctic ice sheets, it is necessary to know the ice sheet thickness and the physical conditions of the ice sheet surface and bed. This information is required at fine resolution and over extensive portions of the ice sheets. A tomographic algorithm has been developed to take raw data collected by a multiple-channel synthetic aperture sounding radar system over a polar ice sheet and convert those data into two-dimensional (2D) ice thickness measurements. Prior to this work, conventional processing techniques only provided one-dimensional ice thickness measurements along profiles.

Wu, Xiaoqing↗
NASA NTRS2013

Simulation of the Microwave Emission of Multi-layered Snowpacks Using the Dense Media Radiative Transfer Theory: the DMRT-ML Model

DMRT-ML is a physically based numerical model designed to compute the thermal microwave emission of a given snowpack. Its main application is the simulation of brightness temperatures at frequencies in the range 1-200 GHz similar to those acquired routinely by spacebased microwave radiometers. The model is based on the Dense Media Radiative Transfer (DMRT) theory for the computation of the snow scattering and extinction coefficients and on the Discrete Ordinate Method (DISORT) to numerically solve the radiative transfer equation. The snowpack is modeled as a stack of multiple horizontal snow layers and an optional underlying interface representing the soil or the bottom ice. The model handles both dry and wet snow conditions. Such a general design allows the model to account for a wide range of snow conditions. Hitherto, the model has been used to simulate the thermal emission of the deep firn on ice sheets, shallow snowpacks overlying soil in Arctic and Alpine regions, and overlying ice on the large icesheet margins and glaciers. DMRT-ML has thus been validated in three very different conditions: Antarctica, Barnes Ice Cap (Canada) and Canadian tundra. It has been recently used in conjunction with inverse methods to retrieve snow grain size from remote sensing data. The model is written in Fortran90 and available to the snow remote sensing community as an open-source software. A convenient user interface is provided in Python.

snowpacks↗
NASA NTRS2013

Extensive Liquid Meltwater Storage in Firn Within the Greenland Ice Sheet

The accelerating loss of mass from the Greenland ice sheet is a major contribution to current sea level rise. Increased melt water runoff is responsible for half of Greenlands mass loss increase. Surface melt has been increasing in extent and intensity, setting a record for surface area melt and runoff in 2012. The mechanisms and timescales involved in allowing surface melt water to reach the ocean where it can contribute to sea level rise are poorly understood. The potential capacity to store this water in liquid or frozen form in the firn (multi-year snow layer) is significant, and could delay its sea-level contribution. Here we describe direct observation of water within a perennial firn aquifer persisting throughout the winter in the southern ice sheet,where snow accumulation and melt rates are high. This represents a previously unknown storagemode for water within the ice sheet. Ice cores, groundairborne radar and a regional climatemodel are used to estimate aquifer area (70 plue or minus 10 x 10(exp 3) square kilometers ) and water table depth (5-50 m). The perennial firn aquifer represents a new glacier facies to be considered 29 in future ice sheet mass 30 and energy budget calculations.

meltwater↗
NASA NTRS2011

Snow Cover, Snowmelt Timing and Stream Power in the Wind River Range, Wyoming

Earlier onset of springtime weather, including earlier snowmelt, has been documented in the western United States over at least the last 50 years. Because the majority (is greater than 70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for the management of streamflow. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work, such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud-gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period as a whole. The extent of snow-cover (percent of basin covered) derived from the lowest elevation zone (2500-3000 m) of the WRR, using MODIS CGF snow-cover maps, is strongly correlated with maximum monthly discharge on 30 April, where Spearman's Rank correlation, rs,=0.89 for the decade of the 2000s. We also investigated stream power for Bull Lake Creek above Bull Lake; and found a trend (significant at the 90% confidence level) toward reduced stream power from 1970 to 2009. Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature measured during the 40-year study period, possibly contributing to a reduction in snow cover. In addition, the strong relationship between percent of basin that was snow covered, and maximum monthly streamflow indicates that MODIS snow-cover maps are useful for predicting streamflow, and can be used to improve management of water resources in the drought-prone western United States.

MODIS↗
NASA NTRS2015

Joint Projections of US East Coast Sea Level and Storm Surge

Future coastal flood risk will be strongly influenced by sea-level rise (SLR) and changes in the frequency and intensity of tropical cyclones. These two factors are generally considered independently. Here, we assess twenty-first century changes in the coastal hazard for the US East Coast using a flood index (FI) that accounts for changes in flood duration and magnitude driven by SLR and changes in power dissipation index (PDI, an integrated measure of tropical cyclone intensity, frequency and duration). Sea-level rise and PDI are derived from representative concentration pathway (RCP) simulations of 15 atmosphere- ocean general circulation models (AOGCMs). By 2080-2099, projected changes in the FI relative to 1986-2005 are substantial and positively skewed: a 10th-90th percentile range 4-75 times higher for RCP 2.6 and 35-350 times higher for RCP 8.5. High-end Fl projections are driven by three AOGCMs that project the largest increases in SLR, PDI and upper ocean temperatures. Changes in PDI are particularly influential if their intra-model correlation with SLR is included, increasing the RCP 8.5 90th percentile FI by a further 25%. Sea-level rise from other, possibly correlated, climate processes (for example, ice sheet and glacier mass changes) will further increase coastal flood risk and should be accounted for in comprehensive assessments.

cyclones↗
NASA NTRS2014

Climate Trends in the Arctic as Observed from Space

The Arctic is a region in transformation. Warming in the region has been amplified, as expected from ice-albedo feedback effects, with the rate of warming observed to be approx. 0.60+/-0.07 C/decade in the Arctic (>64degN) compared to approx. 0.17 C/decade globally during the last three decades. This increase in surface temperature is manifested in all components of the cryosphere. In particular, the sea ice extent has been declining at the rate of approx. 3.8%/decade, whereas the perennial ice (represented by summer ice minimum) is declining at a much greater rate of approx.11.5%/decade. Spring snow cover has also been observed to be declining by −2.12%/decade for the period 1967-2012. The Greenland ice sheet has been losing mass at the rate of approx. 34.0Gt/year (sea level equivalence of 0.09 mm/year) during the period from 1992 to 2011, but for the period 2002-2011, a higher rate of mass loss of approx. 215 Gt/year has been observed. Also, the mass of glaciers worldwide declined at the rate of 226 Gt/year from 1971 to 2009 and 275 Gt/year from 1993 to 2009. Increases in permafrost temperature have also been measured in many parts of the Northern Hemisphere while a thickening of the active layer that overlies permafrost and a thinning of seasonally frozen ground has also been reported. To gain insight into these changes, comparative analysis with trends in clouds, albedo, and the Arctic Oscillation is also presented.

arctic↗
NASA NTRS2015

Modelling Groundwater Depletion at Regional and Global Scales: Present State and Future Prospects.

Except for frozen water in ice and glaciers, groundwater is the world's largest distributed store of freshwater and has strategic importance to global food and water security. In this paper, the most recent advances quantifying groundwater depletion (GWD) are comprehensively reviewed. This paper critically evaluates the recently advanced modeling approaches estimating GWD at regional and global scales, and the evidence of feedbacks to the Earth system including sea-level rise associated with GWD. Finally, critical challenges and opportunities in the use of groundwater are identified for the adaption to growing food demand and uncertain climate.

Groundwater Depletion (GWD)↗
NASA NTRS2015

Watching the Blue Planet from Space over Recent Decades: What's up for Science and Society?

Since the first photographs of “Earth Rise” taken by the Apollo astronauts in the 1960s galvanized the environmental movement, imaging of our planet from low Earth orbit has grown more sophisticated and diverse. Satellite and astronaut observations and imagery of the changing ocean still have the power to galvanize oceanographers and society. So what are some of the key ideas for oceanography and society that come out of out recent decades of ocean observation from space? Satellite oceanography has made fundamental contributions to our understanding and estimation of changing sea level, winds and storminess over the oceans, primary productivity of the seas, the role of the ocean in the water cycle, and the changes in the ocean known as ocean acidification. Some of these phenomena interact in complex ways and Mother Nature hides the future well. However, some things are clear. Sea level rise has been monitored from space for more than 20 years and now we have a more nuanced understanding of regional variation in sea level rise and the contributions of ocean thermal expansion and the melting of glaciers and ice sheets. Wind vectors at the ocean surface have been measured for more than 2 decades and provide evidence for shifts in wind patterns that help, for example, explain some of the regional variations in sea level rise. Chlorophyll-a has been estimated in a multi-decadal record of observations and is being used to describe the shifts and trends in ocean primary productivity. Sea surface temperature estimation from space has records going back to the 1970s and provides critical information for the interaction of the ocean with the atmosphere. Sea surface salinity has been measured from space only within the last decade and provides a novel new view of regional, seasonal, and inter-annual changes in the ocean related to precipitation, river run-off, and eddy transport. Potential changes in the Earth’s water cycle have a huge societal impact.

Blue Planet from Space↗
NASA NTRS2013

The Face that Launched a Thousand Slips

Helene, (approximately 17.6 kilometers mean radius) is an L4 Trojan co-orbital of Saturn's moon Dione. Its hemisphere features an unusual morphology consisting of broad depressions and a generally smooth surface patterned with streaks and grooves. The streaks appear to be oriented down-gradient, as are the grooves. This pattern suggests intensive mass-wasting as a dominant process on the leading hemisphere. Kilometer-scale impact craters are very sparse on the leading hemisphere other than the degraded kilometer-scale basins defining the overall satellite shape, and many small craters have a diffuse appearance suggesting ongoing mass wasting. Thus mass wasting must dominate surface-modifying processes at present. In fact, the mass wasting appears to have been sufficient in magnitude to narrow the divides between adjacent basins to narrow septa, similar, but in lower relief, to the honeycomb pattern of Hyperion. The prominent groves occur primarily near topographic divides and appear have cut into a broad, slightly lower albedo surface largely conforming to the present topography but elevated a few meters above the smooth surfaces undergoing mass wasting flow. Low ridges and albedo markings on the surface suggest surface flow of materials traveling up to several kilometers. Diffusive mass wasting produces smooth surfaces - such a pattern characterizes most of the low-lying surfaces. The grooves, however, imply that the transport process is advective at those locations where they occur, that is, erosion tends to concentrate along linear pathways separated by divides. In fact, in many places grooves have a fairly regular spacing of 125-160 meters, defining a characteristic erosional scale. Several questions are prompted by the unusual morphology of Helene: 1) What is the nature of the surface materials? 2) Are the transport processes gradual or catastrophic motion from one or a few events? 3) What mechanisms drive mass wasting and groove development? 4) Have the formative processes been active in the recent past? 5) Finally, is the surface accreting or eroding? The smooth character of the leading edge hemisphere of Helene and the dominance of mass wasting suggest that the surface is composed of fine-grained debris, probably dominated by dust-size to small gravel particles. The Lagrangian points of saturnian satellites are locations where planetesimals might have accreted to form co-orbital satellites such as and they may capture ejecta from their master moon. Published models suggest that Helene is a site of net accretion, but we find no extant explanation for the dominance of fine grain sizes for the surface (and probable subsurface) composition of Helene and the other Lagrangian satellites. Observation of the mass wasting tracks on Helene suggests the presence of well-defined streams of debris with low bordering levees that may be depositional features or remnants of the dissected higher surface. Some flows in grazing illumination appear to have a convex cross-section. This mass-flow morphology might be consistent with the occurrence of large-scale flow events, but which might have occurred through rapid emplacement or slow glacier-like creep. On the other hand, small craters appear to have been "softened" by creep-like processes, indicating ongoing mass wasting.

honeycomb pattern of Hyperion↗
NASA NTRS2016

Using Unmanned Air Systems to Monitor Methane in the Atmosphere

Methane is likely to be an important contributor to global warming, and our current knowledge of its sources, distributions, and transport is insufficient. It is estimated that there could be from 7.5 to 400 billion tons carbon-equivalent of methane in the arctic region, a broad range that is indicative of the uncertainty within the Earth Science community. Unmanned Air Systems (UASs) are often used for combat or surveillance by the military, but they also have been used for Earth Science field missions. In this study, we will analyze the utility of the NASA Global Hawk and the Aurora Flight Sciences Orion UASs compared to the manned DC-8 aircraft for conducting a methane monitoring mission. The mission will focus on the measurement of methane along the boundaries of Arctic permafrost thaw and melting glaciers. The use of Long Endurance UAS brings a new range of possibilities including the ability to obtain long- term and persistent observations and to significantly augment methane measurements/retrievals collected by satellite. Furthermore, we discuss the future of long endurance UAS and their potential for science applications in the next twenty to twenty-five years.

Clow, Jacqueline↗
NASA NTRS2015

Antarctic Firn Compaction Rates from Repeat-Track Airborne Radar Data: I. Methods

While measurements of ice-sheet surface elevation change are increasingly used to assess mass change, the processes that control the elevation fluctuations not related to ice-flow dynamics (e.g. firn compaction and accumulation) remain difficult to measure. Here we use radar data from the Thwaites Glacier (West Antarctica) catchment to measure the rate of thickness change between horizons of constant age over different time intervals: 2009-10, 2010-11 and 2009-11. The average compaction rate to approximately 25m depth is 0.33ma(exp -1), with largest compaction rates near the surface. Our measurements indicate that the accumulation rate controls much of the spatio-temporal variations in the compaction rate while the role of temperature is unclear due to a lack of measurements. Based on a semi-empirical, steady-state densification model, we find that surveying older firn horizons minimizes the potential bias resulting from the variable depth of the constant age horizon. Our results suggest that the spatiotemporal variations in the firn compaction rate are an important consideration when converting surface elevation change to ice mass change. Compaction rates varied by up to 0.12ma(exp -1) over distances less than 6km and were on average greater than 20% larger during the 2010-11 interval than during 2009-10.

polar firn↗
NASA NTRS2016

Deep Radiostratigraphy of the East Antarctic Plateau: Connecting the Dome C and Vostok Ice Core Sites

Several airborne radar-sounding surveys are used to trace internal reflections around the European Project for Ice Coring in Antarctica Dome C and Vostok ice core sites. Thirteen reflections, spanning the last two glacial cycles, are traced within 200 km of Dome C, a promising region for million-year-old ice, using the University of Texas Institute for Geophysics High-Capacity Radar Sounder. This provides a dated stratigraphy to 2318 m depth at Dome C. Reflection age uncertainties are calculated from the radar range precision and signal-to-noise ratio of the internal reflections. The radar stratigraphy matches well with the Multichannel Coherent Radar Depth Sounder (MCoRDS) radar stratigraphy obtained independently. We show that radar sounding enables the extension of ice core ages through the ice sheet with an additional radar-related age uncertainty of approximately 1/3-1/2 that of the ice cores. Reflections are extended along the Byrd-Totten Glacier divide, using University of Texas/Technical University of Denmark and MCoRDS surveys. However, core-to-core connection is impeded by pervasive aeolian terranes, and Lake Vostok's influence on reflection geometry. Poor radar connection of the two ice cores is attributed to these effects and suboptimal survey design in affected areas. We demonstrate that, while ice sheet internal radar reflections are generally isochronal and can be mapped over large distances, careful survey planning is necessary to extend ice core chronologies to distant regions of the East Antarctic ice sheet.

airborne electromagnetic soundings↗
NASA NTRS2016

The Fiber Optic System for the Advanced Topographic Laser Altimeter System (ATLAS) Instrument

The Advanced Topographic Laser Altimeter System (ATLAS) Instrument has been in integration and testing over the past 18 months in preparation for the Ice, Cloud and Land Elevation Satellite - 2 (ICESat-2) Mission, scheduled to launch in 2017. ICESat-2 is the follow on to ICESat which launched in 2003 and operated until 2009. ATLAS will measure the elevation of ice sheets, glaciers and sea ice or the "cryosphere" (as well as terrain) to provide data for assessing the earth's global climate changes. Where ICESat's instrument, the Geo-Science Laser Altimeter (GLAS) used a single beam measured with a 70 m spot on the ground and a distance between spots of 170 m, ATLAS will measure a spot size of 10 m with a spacing of 70 cm using six beams to measure terrain height changes as small as 4 mm. The ATLAS pulsed transmission system consists of two lasers operating at 532 nm with transmitter optics for beam steering, a diffractive optical element that splits the signal into 6 separate beams, receivers for start pulse detection and a wavelength tracking system. The optical receiver telescope system consists of optics that focus all six beams into optical fibers that feed a filter system that transmits the signal via fiber assemblies to the detectors. Also included on the instrument is a system that calibrates the alignment of the transmitted pulses to the receiver optics for precise signal capture. The larger electro optical subsystems for transmission, calibration, and signal receive, stay aligned and transmitting sufficiently due to the optical fiber system that links them together. The robust design of the fiber optic system, consisting of a variety of multi fiber arrays and simplex assemblies with multiple fiber core sizes and types, will enable the system to maintain consistent critical alignments for the entire life of the mission. Some of the development approaches used to meet the challenging optical system requirements for ATLAS are discussed here.

global climate changes↗
NASA NTRS2016

Horizontal and Vertical Velocities Derived from the IDS Contribution to ITRF2014, and Comparisons with Geophysical Models

In the context of the 2014 realization of the International Terrestrial Reference Frame (ITRF2014), the International DORIS Service (IDS) has delivered to the IERS a set of 1140 weekly SINEX files including station coordinates and Earth orientation parameters, covering the time period from 1993.0 to 2015.0. From this set of weekly SINEX files, the IDS Combination Center estimated a cumulative DORIS position and velocity solution to obtain mean horizontal and vertical motion of 160 stations at 71 DORIS sites. The main objective of this study is to validate the velocities of the DORIS sites by comparison with external models or time series. Horizontal velocities are compared with two recent global plate models (GEODVEL 2010 and NNR-MORVEL56). Prior to the comparisons, DORIS horizontal velocities were corrected for Global Isostatic Adjustment (GIA) from the ICE-6G (VM5a) model. For more than half of the sites, the DORIS horizontal velocities differ from the global plate models by less than 2-3 mm/yr. For five of the sites (Arequipa, Dionysos/Gavdos, Manila, Santiago) with horizontal velocity differences wrt these models larger than 10 mm/yr, comparisons with GNSS estimates show the veracity of the DORIS motions. Vertical motions from the DORIS cumulative solution are compared with the vertical velocities derived from the latest GPS cumulative solution over the time span 1995.0-2014.0 from the University of La Rochelle (ULR6) solution at 31 co-located DORIS-GPS sites. These two sets of vertical velocities show a correlation coefficient of 0.83. Vertical differences are larger than 2 mm/yr at 23 percent of the sites. At Thule the disagreement is explained by fine-tuned DORIS discontinuities in line with the mass variations of outlet glaciers. Furthermore, the time evolution of the vertical time series from the DORIS station in Thule show similar trends to the GRACE equivalent water height.

DORIS↗
NASA NTRS2016

Impacts of Groundwater Pumping on Regional and Global Water Resources

Except frozen water in ice and glaciers (68%), groundwater is the world's largest distributed store of freshwater (30%), and has strategic importance to global food and water security. In this chapter, the most recent advances assessing human impact on regional and global groundwater resources are reviewed. This chapter critically evaluates the recently advanced modeling approaches quantifying the effect of groundwater pumping in regional and global groundwater resources and the evidence of feedback to the Earth system including sea‐level rise associated with groundwater use. At last, critical challenges and opportunities are identified in the use of groundwater to adapt to growing food demand and uncertain climate.

groundwater↗
NASA NTRS2017

A Water Rich Mars Surface Mission Scenario

In an on-going effort to make human Mars missions more affordable and sustainable, NASA continues to investigate the innovative leveraging of technological advances in conjunction with the use of accessible Martian resources directly applicable to these missions. One of the resources with the broadest utility for human missions is water. Many past studies of human Mars missions assumed a complete lack of water derivable from local sources. However, recent advances in our understanding of the Martian environment provides growing evidence that Mars may be more "water rich" than previously suspected. This is based on data indicating that substantial quantities of water are mixed with surface regolith, bound in minerals located at or near the surface, and buried in large glacier-like forms. This paper describes an assessment of what could be done in a "water rich" human Mars mission scenario. A description of what is meant by "water rich" in this context is provided, including a quantification of the water that would be used by crews in this scenario. The different types of potential feedstock that could be used to generate these quantities of water are described, drawing on the most recently available assessments of data being returned from Mars. This paper specifically focuses on sources that appear to be buried quantities of water ice. (An assessment of other potential feedstock materials is documented in another paper.) Technologies and processes currently used in terrestrial polar regions is reviewed. One process with a long history of use on Earth and with potential application on Mars - the Rodriguez Well - is described and results of an analysis simulating the performance of such a well on Mars are presented. These results indicate that a Rodriguez Well capable of producing the quantities of water identified for a "water rich" human mission are within the capabilities assumed to be available on the Martian surface, as envisioned in other comparable Evolvable Mars Campaign assessments. The paper concludes by capturing additional findings and describing additional simulations and tests that should be conducted to better characterize the performance of the identified terrestrial technologies for accessing subsurface ice, as well as the Rodriguez Well, under Mars environmental conditions.

Hoffman, Stephen J.↗