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NASA NTRS1999

Modeling the Effect of Wetlands, Flooding, and Irrigation on River Flow: Application to the Aral Sea

As the world's population continues to increase, additional stress is placed on water resources. This stress, coupled with future uncertainties regarding climate change, makes arid and semi-arid regions particularly vulnerable. One example is the Aral Sea where the freshwater inflow, which is dominated by snowmelt runoff, has decreased significantly since the expansion of intensive irrigation in the 1960s. The purpose of this paper is to use a river routing scheme from a global climate model to examine the flow of the Amu Dar'ya River into the Aral Sea. The river routing scheme is modified to include groundwater flow, flooding, and evaporative losses in the river's wetlands and floodplain, and anthropogenic withdrawals for irrigation. A set of scenarios is designed to test the sensitivity of river flow to the inclusion of these modifications into the river routing scheme. When riverine wetlands and floodplains are present, the river flow is reduced significantly and is similar to the observed flow. In addition the model results show that it is essential to incorporate human diversions to accurately represent the inflow to the Aral Sea, and they also indicate potential management strategies that might be appropriate to maintain a balance between inflow to the Sea and upstream diversions for irrigation.

Ferrari, Michael R.↗

NASA NTRS2000

NASA Information Technology Implementation Plan

NASA's Information Technology (IT) resources and IT support continue to be a growing and integral part of all NASA missions. Furthermore, the growing IT support requirements are becoming more complex and diverse. The following are a few examples of the growing complexity and diversity of NASA's IT environment. NASA is conducting basic IT research in the Intelligent Synthesis Environment (ISE) and Intelligent Systems (IS) Initiatives. IT security, infrastructure protection, and privacy of data are requiring more and more management attention and an increasing share of the NASA IT budget. Outsourcing of IT support is becoming a key element of NASA's IT strategy as exemplified by Outsourcing Desktop Initiative for NASA (ODIN) and the outsourcing of NASA Integrated Services Network (NISN) support. Finally, technology refresh is helping to provide improved support at lower cost. Recently the NASA Automated Data Processing (ADP) Consolidation Center (NACC) upgraded its bipolar technology computer systems with Complementary Metal Oxide Semiconductor (CMOS) technology systems. This NACC upgrade substantially reduced the hardware maintenance and software licensing costs, significantly increased system speed and capacity, and reduced customer processing costs by 11 percent.

Source record↗

NASA NTRS1998

Mapping the Distribution of Wildfire Fuels Using AVIRIS in the Santa Monica Mountains

Catastrophic wildfires, such as the 1990 Painted Cave Fire in Santa Barbara or Oakland fire of 1991, attest to the destructive potential of fire in the wildland/urban interface. For example, during the Painted Cave Fire, 673 structures were consumed over a period of only six hours at an estimated cost of 250 million dollars (Gomes et al., 1993). One of the primary sources of fuels is chaparral, which consists of plant species that are adapted to frequent fires and may actually promote its ignition and spread of through volatile organic compounds in foliage. As one of the most widely distributed plant communities in Southern California, and one of the most common vegetation types along the wildland urban interface, chaparral represents one of the greatest sources of wildfire hazard in the region. An ongoing NASA funded research project was initiated in 1994 to study the potential of AVIRIS for mapping wildfire fuel properties in Southern California chaparral. The project was initiated in the Santa Monica Mountains, an east-west trending range in western Los Angeles County that has experienced extremely high fire frequencies over the past 70 years. The Santa Monica Mountains were selected because they exemplify many of the problems facing the southwest, forming a complex mosaic of land ownership intermixed with a diversity of chaparral age classes and fuel loads. Furthermore, the area has a wide diversity of chaparral community types and a rich background in supporting geographic information including fire history, soils and topography. Recent fires in the Santa Monica Mountains, including several in 1993 and the Calabasas fire of 1996 attest to the active fire regime present in the area. The long term objectives of this project are to improve existing maps of wildland fuel properties in the area, link AVIRIS derived products to fuel models under development for the region, then predict fire hazard through models that simulate fire spread. In this paper, we describe the AVIRIS derived products we are developing to map wildland fuels.

Roberts, Dar↗

NASA NTRS1999

A Survey of Environmental Microbial Flora During Closed Chamber Studies

Services, Inc. and NASA Johnson Space Center, Houston, TX As NASA prepares for long-term missions aboard the International Space Station and the eventual exploration of Mars, closed-environment chambers on Earth have become important test beds for systems evaluations. During 2 separate studies of a selfcontained ecosystem containing 4 crewmembers, microbial surveys of samples from 13 surface and 3 air sites were performed. Microbial concentration of samples from surface sites with frequent water contact (e.g., urinal, sink) did not indicate significantly higher levels of contamination than drier areas, though surface cleaning by the crew may have influenced this conclusion. Changes in bacterial diversity on surface sites implied that the number of transient species was high, suggesting movement by crew activities, aerosols, or both. A non-linear relationship between bacterial diversity and enumeration from surface samples indicated that a rapid increase occurred in the number of species as cell concentration increased to 5 CFU/sq cm. Above this concentration, the number of different bacterial species varied between 11 and 16. Airborne bacteria and fungi averaged only 160 and 1 CFU/m3, respectively. Microbial contamination of the potable water system primarily consisted of 3 species of Gram negative bacteria; however, after 60 days during one study, several species of Bacillus became the dominant flora. This study suggests that under these conditions, microbial contamination in the air and water was suppressed by the life-support systems, though contamination was possible. Conversely, the crew and their activities controlled microbial levels on surfaces. Understanding the factors that affect microbial control will improve the design of microbial testing both during space flight and in analogous Earth-based environments.

Ott, C. Mark↗

NASA NTRS1999

Sampling the Old and the New: Landing Site Proposals for the Dichotomy Boundary (6 S,210 W) and the Ares Vallis Headlands (2 S,18 W)

One of the goals of the Mars Pathfinder mission was to sample a diversity of rocks deposited by the Ares and Tiu Vallis floods. It was hoped that ancient highlands and younger lowlands material could be studied, as well as a diversity of rocks within these regions. Although Pathfinder found rocks that exhibited a number of textures and morphologies, several factors precluded the identification of a petrologic suite of rocks, if it was present. Namely among these were 1) The lack of geologic context for the rocks examined, 2) instrument limitations, and 3) pervasive dust and possible weathering finds. Based on the Pathfinder experience and incorporating recent results from Mars Global Surveyor and previous missions, two landing sites are proposed that can potentially overcome this problem and offer samples of ancient and recent Martian rock. The first site is at the dichotomy boundary, where ancient highlands and more recent lowlands meet. The second site is at the Ares Vallis headlands, where some of the source materials for the Pathfinder landing site may have been derived. Both of these sites meet the remote sensing and elevation constraints of the 2001 Lander mission but exhibit significant slopes and potential hazards in places. However, a properly placed ellipse can alleviate much of the concern, thereby offering two exciting sites that otherwise would not be chosen.

Bridges, N. T.↗

NASA NTRS1999

The Confluence of Gangis and Eos Chasmas (5-12 deg S, 31-41 deg W): Geologic, Hydrologic, and Exobiologic Considerations for Landing Site at the East End of Valles Marineris

Over its 3,500 km length, Valles Marineris exhibits an enormous range of geologic and environmental diversity. At its western end, the canyon is dominated by the tectonic complex of Noctis Labyrinthus; while in the east it grades into an extensive region of chaos where scoured channels and streamlined islands provide evidence of catastrophic floods that spilled into the northern plains. In the central portion of the system, debris derived from the massive interior layered deposits of Candor and Ophir Chasmas spills into the central trough. In other areas, 6 km-deep exposures of Hesperian and Noachian-age canyon wall stratigraphy have collapsed in massive landslides that extend many tens of kilometers across the canyon floor. Ejecta from interior craters, aeolian sediments, and possible volcanics emanating from structurally controlled vents along the base of the scarps, further contribute to the canyon's geologic complexity. Following the initial rifting that gave birth to Valles Marineris, water appears to have been a principal agent in the canyon's geomorphic development an agent whose significance is given added weight by its potential role in both sustaining and preserving evidence of past life. In this regard, the interior layered deposits of Candor, Ophir, and Hebes Chasmas, have been identified as possible lucustrine sediments that may have been laid down in long-standing ice-covered lakes. The potential survival and growth of native organisms in such an environment, or in the aquifers whose disruption gave birth to the chaotic terrain and outflow channels to the north and east of the canyon, raises the possibility that fossil indicators of life may be present in the local sediment and rock. Because of the enormous distances over which these diverse environments occur, identifying a single landing site that maximizes the opportunity for scientific return is not a simple task. However, given the fluvial history and narrow geometry of the canyon, the presence of a single exit at its eastern end provides an opportunity for sampling that appears unequaled elsewhere in the system.

George, J. A.↗

NASA NTRS2000

Computing Needs for Astrobiology: Models of Planetary Formation

Theories of planet formation indicate that a diverse range of physical and chemical processes determine the characteristics of a planetary system. Extensive numerical modeling is required to understand how planetary systems form, and to make quantitative assessments of the factors which determine the masses, spacings and volatile compound inventories of planets and small bodies within a planetary system. Fluid flow problems associated with the formation and evolution of protoplanetary disks include specific local calculations to provide physical insight, which are best performed on workstations, and large multifaceted simulations which require supercomputers with large memories. Formation and early growth of planetesimals display a similar range of computational requirements. Modeling the late stages of planetary accumulation is very CPU intensive, as it requires following a simple system of approx. hundreds of bodies for millions of dynamical (orbital) times. These varied computational needs could be met in the most cost-effective manner by a diverse set of computers, including workstations for individual PI's and dedicated time on various types of supercomputers which are specialized for differing tasks.

Lissauer, Jack J.↗

NASA NTRS2000

The Effect of Dilution on the Structure of Microbial Communities

To determine how dilution of microbial communities affects the diversity of the diluted assemblage a series of numerical simulations were conducted that determined the theoretical change in diversity, richness, and evenness of the community with serial dilution. The results of the simulation suggested that the effects are non linear with a high degree of dependence on the initial evenness of the community being diluted. A series of incubation experiments using a range of dilutions of raw sewage as an inoculum into sterile sewage was used for comparison to the simulations. The diluted communities were maintained in batch fed reactors (three day retention time) for nine days. The communities were harvested and examined by conventional plating and by molecular analysis of the whole-community DNA using AFLP and T-RFLP. Additional, CLPP analysis was also applied. The effects on richness predicted by the numerical simulations were confirmed by the analyses used. The diluted communities fell into three groups, a low dilution, intermediate dilution, and high dilution group, which corresponded well with the groupings obtained for community richness in simulation. The grouping demonstrated the non-linear nature of dilution of whole communities. Furthermore, the results implied that the undiluted community consisted of a few dominant types accompanied by a number of rare (low abundance) types as is typical in unevenly distributed communities.

Mills, Aaron L.↗

NASA NTRS2001

Airborne Sunphotometer Studies of Aerosol Properties and Effects, Including Closure Among Satellite, Suborbital Remote, and In situ Measurements

Airborne sunphotometry has been used to measure aerosols from North America, Europe, and Africa in coordination with satellite and in situ measurements in TARFOX (1996), ACE-2 (1997), PRIDE (2000), and SAFARI 2000. Similar coordinated measurements of Asian aerosols are being conducted this spring in ACE-Asia and are planned for North American aerosols this summer in CLAMS. This paper summarizes the approaches used, key results, and implications for aerosol properties and effects, such as single scattering albedo and regional radiative forcing. The approaches exploit the three-dimensional mobility of airborne sunphotometry to access satellite scenes over diverse surfaces (including open ocean with and without sunglint) and to match exactly the atmospheric layers sampled by airborne in situ measurements and other radiometers. These measurements permit tests of the consistency, or closure, among such diverse measurements as aerosol size-resolved chemical composition; number or mass concentration; light extinction, absorption, and scattering (total, hemispheric back and 180 deg.); and radiative fluxes. In this way the airborne sunphotometer measurements provide a key link between satellite and in situ measurements that helps to understand any discrepancies that are found. These comparisons have led to several characteristic results. Typically these include: (1) Better agreement among different types of remote measurements than between remote and in situ measurements. (2) More extinction derived from transmission measurements than from in situ measurements. (3) Larger aerosol absorption inferred from flux radiometry than from in situ measurements. Aerosol intensive properties derived from these closure studies have been combined with satellite-retrieved fields of optical depth to produce fields of regional radiative forcing. We show results for the North Atlantic derived from AVHRR optical depths and aerosol intensive properties from TARFOX and ACE-2. Companion papers show analogous, preliminary results for Asian-Pacific aerosols and results of SAFARI-2000 closure studies on African aerosols.

Russlee, Philip B.↗

NASA NTRS2001

A Structural and Molecular Approach for the Study Biomarkers

Investigation of the nucleation and growth of crystals in both abiotic and biotic systems is critical to seemingly diverse disciplines of geology, biology, environmental science, and astrobiology. While there are abundant studies devoted to the determination of the structure and composition of inorganic crystals, as well as to the development of thermodynamic and kinetic models, it is only recently that research efforts have been directed towards understanding mineralization in biological systems (i.e., biomineralization). Biomineralization refers to the processes by which living organisms form inorganic solids. Studies of the processes of biomineralization under low temperature aqueous conditions have focused primarily on magnetite forming bacteria and shell forming marine organisms. Many of the biological building materials consist of inorganic minerals (calcium carbonate, calcium phosphate, silica or iron oxide) intricately combined with organic polymers (like proteins). More recently, efforts have been undertaken to explore the nature of biological activities in ancient rocks. In the absence of well-preserved microorganisms or genetic material required for the polmerase chain reaction (PCR) method in molecular phylogenetic studies, using biominerals as biomarkers offers an alternative approach for the recognition of biogenic activity in both terrestrial and extraterrestrial environments. The primary driving force in biomineralization is the interaction between organic and inorganic phases. Thus, the investigation of the ultrastructure and the nature of reactions at the molecular level occurring at the interface between inorganic and organic phases is essential to understanding the processes leading to the nucleation and growth of crystals. It is recognized that crystal surfaces can serve as the substrate for the organization of organic molecules that lead to the formation of polymers and other complex organic molecules, and in discussions of the origins of life, is referred to as organic synthesis on mineral surfaces. Furthermore, it is suggested that the interaction between mineral surfaces and simple organic molecules resulted in the formation of amino acids, RNA, and perhaps other more complex molecules such as proteins. On the other hand, in natural systems, it is recognized that functional groups on cell walls or membranes of microorganisms serve as sites of nucleation and crystallization. The precise replication of biominerals with controlled structure, morphology, size and texture is not confined to higher organisms as it also occurs in primitive prokaryotic cells such as magnetotactic bacteria and cyanobacteria. This suggests that the principal strategies of biomineralization were established early on in the evolutionary history of organisms. It is critical, therefore, to search for common mechanisms within diverse biological systems. One such common factor is the capability for organization and self-assembly. Organic macromolecules such as proteins and lipids can aggregate and polymerize forming membranes or extracellular matrix. At the organic-inorganic interface, several factors such as lattice geometry, polarity, stereochemistry and topography may act in concert to control nucleation and growth of crystals. Although several models have been proposed that discuss the significance of these factors for biomineralization, no comprehensive experimental data are available. In contrast to crystallization in exclusively inorganic systems, the kinetics of reaction and structural relationships between organic and inorganic phases in biominerals or biomimetic material is poorly understood. For example, it is not clear if the concept of epitactic growth (geometrical matching of unit cells at the interface of a secondary crystal growing on a primary crystal) applies to organic-inorganic systems. In contrast to inorganic templates that often have a smooth and rigid surface that promotes epitactic growth, biological substrates are usually rough and result in a large degree of mismatch. It is apparent that factors controlling the reaction at the crystal-matrix interface are strongly dependent upon the nature of the substrate. Therefore, characterization of the assembled organic surface and surface structure of the inorganic phase is crucial to understanding the processes of biomineralization. The focus of our research is the investigation of the processes leading to the nucleation and growth of crystals on both natural and synthetic systems through an interdisciplinary approach that integrates molecular biology, morphology and mineralogy using advanced preparation and analytical techniques. We have studied run-products, particularly magnetite, siderite and other carbonates, that resulted from extracellular biomineralization by extremophiles isolated from a variety of extreme environments ranging from permafrost to hydrothermal vent systems. The results of this study are critical to recognizing biomarkers in terrestrial and extraterrestrial environments.

Thomas-Keprta, Kathie↗

NASA NTRS1995

Training for Aviation Decision Making: The Naturalistic Decision Making Perspective

This paper describes the implications of a naturalistic decision making (NDM) perspective for training air crews to make flight-related decisions. The implications are based on two types of analyses: (a) identification of distinctive features that serve as a basis for classifying a diverse set of decision events actually encountered by flight crews, and (b) performance strategies that distinguished more from less effective crews flying full-mission simulators, as well as performance analyses from NTSB accident investigations. Six training recommendations are offered: (1) Because of the diversity of decision situations, crews need to be aware that different strategies may be appropriate for different problems; (2) Given that situation assessment is essential to making a good decision, it is important to train specific content knowledge needed to recognize critical conditions, to assess risks and available time, and to develop strategies to verify or diagnose the problem; (3) Tendencies to oversimplify problems may be overcome by training to evaluate options in terms of goals, constraints, consequences, and prevailing conditions; (4) In order to provide the time to gather information and consider options, it is essential to manage the situation, which includes managing crew workload, prioritizing tasks, contingency planning, buying time (e.g., requesting holding or vectors), and using low workload periods to prepare for high workload; (5) Evaluating resource requirements ("What do I need?") and capabilities ("'What do I have?" ) are essential to making good decisions. Using resources to meet requirements may involve the cabin crew, ATC, dispatchers, and maintenance personnel; (6) Given that decisions must often be made under high risk, time pressure, and workload, train under realistic flight conditions to promote the development of robust decision skills.

Orasanu, Judith↗

NASA NTRS2002

Pristine Igneous Rocks and the Genesis of Early Planetary Crusts

Our studies are highly interdisciplinary, but are focused on the processes and products of early planetary and asteroidal differentiation, especially the genesis of the ancient lunar crust. The compositional diversity that we explore is the residue of process diversity, which has strong relevance for comparative planetology.

Warren, Paul H.↗

NASA NTRS1998

Methodology for Examining the Operator and the System Concurrently: Pilot Interaction with Automation

Complex system description is problematic when considering operator task activities interacting with system dynamics. Engineering languages have matured sufficiently to allow machine system description at various levels of depth and breadth but without operator synergy. Concurrently, Task Analysis methods have evolved along diverse lines enabling a description of the operator in the system from various paradigms but not describing the system. A void exists when attempting to view the system and the operator in the same plane. We propose a methodology employing descriptive languages from different domains viewed in a single dimension. Finite Automata (FA) languages describe the machine system in the proposed approach. Operator task specifications, a form of task analysis output, examine the operator activities within the system. Operator task specifications were then selected for discrete task activities and overlaid on the system description to examine operator inputs and subsequently view system responses. Unexpected (surprise) and undesirable system behavior was expected to emerge from this analysis. In this paper we shall first describe the methodology and show how the two perspectives, machine model and operator task specifications are integrated. Following we describe the process of doing such analysis using an example from cockpit automation. The methodology was employed in the analysis of a new function that was added to an existing automatic flight control system. We begin by defining a flight scenario involving all aspects of pilot interaction with the new function. Then, we proceed to develop a basic model of the machine behavior, in the context of pilot actions. Finally we superimpose the operator task specification on the machine model and perform the analysis. The proposed methodology may have broad appeal to system designers and human factors specialists. A common language for engineers of diverse domains is a strong point of this approach. Systems engineers may not fully understand operational considerations and human limitations, and human factors specialists may not be exposed to the full extent of system behavior. We hope the proposed methodology is adopted by both disciplines and in the process each assimilates a common language to address potential shortcomings of either approach separately.

Austin, David↗

NASA NTRS1998

Identification of Extraterrestrial Microbiology

Many of the key questions addressed in the field of Astrobiology are based upon the assumption that life exists, or at one time existed, in locations throughout the universe. However, this assumption is just that, an assumption. No definitive proof exists. On Earth, life has been found to exist in many diverse environment. We believe that this tendency towards diversity supports the assumption that life could exists throughout the universe. This paper provides a summary of several innovative techniques for the detection of extraterrestrial life forms. The primary questions addressed are does life currently exist beyond Earth and if it does, is that life evolutionary related to life on Earth?

Flynn, Michael↗

NASA NTRS2002

IDEA: Planning at the Core of Autonomous Reactive Agents

Several successful autonomous systems are separated into technologically diverse functional layers operating at different levels of abstraction. This diversity makes them difficult to implement and validate. In this paper, we present IDEA (Intelligent Distributed Execution Architecture), a unified planning and execution framework. In IDEA a layered system can be implemented as separate agents, one per layer, each representing its interactions with the world in a model. At all levels, the model representation primitives and their semantics is the same. Moreover, each agent relies on a single model, plan database, plan runner and on a variety of planners, both reactive and deliberative. The framework allows the specification of agents that operate, within a guaranteed reaction time and supports flexible specification of reactive vs. deliberative agent behavior. Within the IDEA framework we are working to fully duplicate the functionalities of the DS1 Remote Agent and extend it to domains of higher complexity than autonomous spacecraft control.

Muscettola, Nicola↗

NASA NTRS2002

Visible to Short Wavelength Infrared Spectroscopy on Rovers: Why We Need it on Mars and What We Need to do on Earth

The next stage of Mars exploration will include the use of rovers to seek out specific mineralogies. Understanding the mineralogical diversity of the locale will be used to determining which targets should be investigated with the full suite of in situ capability on the rover. Visible to Short Wavelength Infrared (VSWIR) spectroscopy is critical in evaluating the mineralogical diversity and to validate the global remote sensing data sets to be collected by Mars Express and the Mars Reconnaissance Orbiter. However, spectroscopy on mobile platforms present challenges in both the design of instruments and in the efficient operation of the instrument and mission. Field-testing and validation on Earth can be used to develop instrument requirements analysis tools needed for used on Mars.

Blaney, D. L.↗

NASA NTRS2003

A Critical Examination of Relative Concentrations of Volume-correlated and Surface-correlated Submicron Globules of Pure Fe-0 in Lunar Soils

Impacts on lunar soils produce melt and vapor in an approximate proportion of 7:1. The melt scavenges soil grains of diverse size, quenches and forms agglutinates, thereby converting surface correlated components of soil grains as volume correlated components; simultaneously, parts of the vapor may condense or escape. Cumulative small impacts increase the maturity of the soils, increase the abundance of agglutinates, and increase the concentration of vapor condensated material. Since the discovery of vapor deposited crystalline Fe-0 in vugs of regolith breccias and the theoretical anticipation of amorphous vapor deposits of diverse composition coating lunar soils grains, empirical evidence is gathering in support of such deposits, now commonly called vapor deposited patina (VDP). In addition, submicron globules of Fe-0 are seen to be ubiquitous in VDP. The amorphous VDP lowers the albedo of lunar soils, affects magnetic properties of soils, changes the slopes of uv-vis-ir reflectance spectra, and potentially also alters the gamma and x-ray spectra of lunar soils, compromising compositional inferences from remote sensing.

Basu, A.↗

NASA NTRS2003

Astrobiological Significance of Chemolithoautotrophic Acidophiles

For more than a century (since Winogradsky discovered lithoautotrophic bacteria) a dilemma in microbiology has concerned life that first inhabited the Earth. Which types of life forms first appeared in the primordial oceans during the earliest geological period on Earth as the primary ancestors of modem biological diversity? How did a metabolism of ancestors evolve: from lithoautotrophic to lithohetherotrophic and organoheterotrophic or from organoheterotrophic to organoautotrophic and lithomixotrophic types? At the present time, it is known that chemolithoheterotrophic and chemolithoautotrophic metabolizing bacteria are wide spread in different ecosystems. On Earth the acidic ecosystems are associated with geysers, volcanic fumaroles, hot springs, deep sea hydrothermal vents, caves, acid mine drainage and other technogenic ecosystems. Bioleaching played a significant role on a global geological scale during the Earth's formation. This important feature of bacteria has been successfully applied in industry. The lithoautotrophs include Bacteria and Archaea belonging to diverse genera containing thermophilic and mesophilic species. In this paper we discuss the lithotrophic microbial acidophiles and present some data with a description of new acidophilic iron- and sulfur- oxidizing bacterium isolated from the Chena Hot Springs in Alaska. We also consider the possible relevance of microbial acidophiles to Venus, Io, and acidic inclusions in glaciers and icy moons.

Pikuta, Elena V.↗