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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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NASA NTRS2007

NEXT Ion Propulsion System Configurations and Performance for Saturn System Exploration

The successes of the Cassini/Huygens mission have heightened interest to return to the Saturn system with focused robotic missions. The desire for a sustained presence at Titan, through a dedicated orbiter and in-situ vehicle, either a lander or aerobot, has resulted in definition of a Titan Explorer flagship mission as a high priority in the Solar System Exploration Roadmap. The discovery of active water vapor plumes erupting from the tiger stripes on the moon Enceladus has drawn the attention of the space science community. The NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system is well suited to future missions to the Saturn system. NEXT is used within the inner solar system, in combination with a Venus or Earth gravity assist, to establish a fast transfer to the Saturn system. The NEXT system elements are accommodated in a separable Solar Electric Propulsion (SEP) module, or are integrated into the main spacecraft bus, depending on the mission architecture and performance requirements. This paper defines a range of NEXT system configurations, from two to four thrusters, and the Saturn system performance capability provided. Delivered mass is assessed parametrically over total trip time to Saturn. Launch vehicle options, gravity assist options, and input power level are addressed to determine performance sensitivities. A simple two-thruster NEXT system, launched on an Atlas 551, can deliver a spacecraft mass of over 2400 kg on a transfer to Saturn. Similarly, a four-thruster system, launched on a Delta 4050 Heavy, delivers more than 4000 kg spacecraft mass. A SEP module conceptual design, for a two thruster string, 17 kW solar array, configuration is characterized.

Benson, Scott W.↗
NASA NTRS2001

Boiler Tube Corrosion Characterization with a Scanning Thermal Line

Wall thinning due to corrosion in utility boiler water wall tubing is a significant operational concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. Unfortunately, ultrasonic inspection is very manpower intense and slow. Therefore, thickness measurements are typically taken over a relatively small percentage of the total boiler wall and statistical analysis is used to determine the overall condition of the boiler tubing. Other inspection techniques, such as electromagnetic acoustic transducer (EMAT), have recently been evaluated, however they provide only a qualitative evaluation - identifying areas or spots where corrosion has significantly reduced the wall thickness. NASA Langley Research Center, in cooperation with ThermTech Services, has developed a thermal NDE technique designed to quantitatively measure the wall thickness and thus determine the amount of material thinning present in steel boiler tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed and accuracy for large structures such as boiler water walls. A theoretical basis for the technique will be presented to establish the quantitative nature of the technique. Further, a dynamic calibration system will be presented for the technique that allows the extraction of thickness information from the temperature data. Additionally, the results of the application of this technology to actual water wall tubing samples and in-situ inspections will be presented.

Cramer, K. Elliott↗
NASA NTRS2011

Global Assimilation of Multi-Sensor Snow Observations for Improved Characterization of Snow Processes

Snow conditions on the land surface are recognized to be key components of the global hydrological cycle as they play a critical role in the determination of local and regional climate. In many mid-latitude and high-latitude regions, the seasonal water storage and associated spring snowmelt dominate the local hydrology. The contribution to the runoff and moisture conditions from snow is vital in supporting agriculture and in determining water resources management practices. Consequently, accurate characterization of snow properties becomes important for both end-use applications and weather and climate research. Recently a joint effort between the u.S. Air Force and NASA has enabled a blended, multi-sensor snow product known as the AFWA NASA Snow Algorithm (ANSA). This global snow dataset has been generated by utilizing the Earth Observation System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer for EOS (AMSR-E) datasets. ANSA product includes estimates of snow cover extent, snow water equivalent (SWE) and SWE-derived snow depth fields. The MODIS-based products enable snow cover mappings under cloud-free conditions whereas the passive microwave data from AMSR-E provides measurements under cloudy conditions. These remotely-sensed snow observations are further augmented with the information from ground-based snow measurements through data fusion techniques. The resulting ANSA products are employed in the NASA Land Information System (LIS) data assimilation framework, which provides a comprehensive environment for integrating community land surface models, ground and satellite-based observations, and ensemble-based data assimilation tools. LIS incorporates the multisensor ANSA snow retrievals with the land surface model estimates to generate spatially and temporally continuous estimates of snow states, through data assimilation. A suite of experiments to assimilate ANSA snow cover, SWE and snow depth estimates with different land surface models in LIS are conducted and the resulting estimates of snow conditions are evaluated against a number of in-situ observational datasets, over several regions of the world. These evaluations are used to compare and contrast the advantages and disadvantages of these multi-sensor snow observations.

Kumar, Sujay↗
NASA NTRS1992

Mars Environmental Survey (MESUR): Science objectives and mission description

In-situ observations and measurements of Mars are objectives of a feasibility study beginning at the Ames Research Center for a mission called the Mars Environmental SURvey (MESUR). The purpose of the MESUR mission is to emplace a pole-to-pole global distribution of landers on the Martian surface to make both short- and long-term observations of the atmosphere and surface. The basic concept is to deploy probes which would directly enter the Mars atmosphere, provide measurements of the upper atmospheric structure, image the local terrain before landing, and survive landing to perform meteorology, seismology, surface imaging, and soil chemistry measurements. MESUR is intended to be a relatively low-cost mission to advance both Mars science and human presence objectives. Mission philosophy is to: (1) 'grow' a network over a period of years using a series of launch opportunities, thereby minimizing the peak annual costs; (2) develop a level-of-effort which is flexible and responsive to a broad set of objectives; (3) focus on science while providing a solid basis for human exploration; and (4) minimize project cost and complexity wherever possible. In order to meet the diverse scientific objectives, each MESUR lander will carry the following strawman instrument payload consisting of: (1) Atmospheric structure experiment, (2) Descent and surface imagers, (3) Meteorology package, (4) Elemental composition instrument, (5) 3-axis seismometer, and (6) Thermal analyzer/evolved gas analyzer. The feasibility study is primarily to show a practical way to design an early capability for characterizing Mars' surface and atmospheric environment on a global scale. The goals are to answer some of the most urgent questions to advance significantly our scientific knowledge about Mars, and for planning eventual exploration of the planet by robots and humans.

Hubbard, G. Scott↗
NASA NTRS2000

Solid Freeform Fabrication of Continuous Fiber Reinforced Composites for Propulsion Applications

For propulsion related applications, materials must be able to demonstrate excellent ablation and oxidation resistance at temperature approaching 3500'C, adequate load bearing capabilities, non-catastrophic failure modes, and ability to withstand transient thermal shock. A potential list of propulsion-material property requirements includes, low density, high elastic modulus, low thermal-expansion coefficient, high thermal conductivity, excellent erosion and oxidation/corrosion resistance, and flaw-insensitivity. In many cases, they will also need to be able to be joined, survive thermal cycling and multi-axial stress states, and for reusable applications, the materials must maintain the above attributes after prolonged exposure to extremely harsh chemical environments. The final and possibly most important attribute for these materials are the need to be lower cost and readily available in large quantities. Recently, Advanced Ceramics Research, Inc. (ACR) has developed low cost, flexible- manufacturing processes for Zr & Hf-based carbon fiber reinforced composites, materials with good oxidation and ablation resistance up to 3500 C. This process, called Continuous Composite Co-extrusion (C(sup 3)), incorporates carbon fibers to fabricate 'in-situ' carbide and boride-matrix/carbon fiber composites. This is a variation of ACR's manufacturing process for low-cost structural ceramic materials called Fibrous Monoliths With carbon fiber reinforcements. Fibrous Monolithic materials have a distinct fibrous texture, consist of intertwined cells of a primary phase, separated by cell boundaries of a tailored secondary phase and show very high fracture energies, damage tolerance, and graceful failure. Since they are monolithic powder based composites-, they can be manufactured by conventional powder processing techniques using inexpensive raw materials. This combination of high performance and low cost is a breakthrough that could enable wider application of ceramics in high temperature applications. Typical volume fractions of the two phases are 80 to 95% for the cell phase and 5 to 20% for the interpenetrating cell boundary phase. ACR is currently developing an innovative solid freeform form fabrication (SFF) approach to produce Hf and Zr based ceramic composite components reinforced with continuous carbon fiber tows for critical structural components such as tubes and blisks. The process is simple, robust and will be widely applicable to a number of material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The current process is being developed in collaboration with UD-CCM. The paper will detail the freeform fabrication process to create low-cost ceramic fiber reinforced composites for high-temperature applications. The results of mechanical properties and microstructural characterization will be presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts for propulsion applications at an order of magnitude lower cost than current CVI and PIP process.

Vaidyanathan, R.↗
NASA NTRS2001

Solid Free-Form Fabrication of Continuous Fiber Reinforced Composites for Propulsion Application

For propulsion related applications, materials must be able to demonstrate excellent ablation and oxidation resistance at temperature approaching 3500 C, adequate load bearing capabilities, non-catastrophic failure modes, and ability to withstand transient thermal shock. A potential list of propulsion-material property requirements includes, low density, high elastic modulus, low thermal-expansion coefficient, high thermal conductivity, excellent erosion and oxidation/corrosion resistance, and flaw-insensitivity. In many cases, they will also need to be able to be joined, survive thermal cycling and multi-axial stress states, and for reusable applications, the materials must maintain the above attributes after prolonged exposure to extremely harsh chemical environments. The final and possibly most important attribute for these materials are the need to be lower cost and readily available in large quantities. Recently, Advanced Ceramics Research, Inc. (ACR) has developed low cost, flexible-manufacturing processes for Zr & Hf-based carbon fiber reinforced composites, materials with good oxidation and ablation resistance up to 3500 C. This process, called Continuous Composite Co-extrusion (C(sup 3)), incorporates carbon fibers to fabricate 'in-situ' carbide and boride-matrix/carbon fiber composites. M is a variation of ACR's manufacturing process for low-cost structural ceramic materials called Fibrous Monoliths with carbon fiber reinforcements. Fibrous Monolithic materials have a distinct fibrous texture, consist of intertwined cells of a primary phase, separated by cell boundaries of a tailored secondary phase and show very high fracture energies, damage tolerance, and graceful failure. Since they are monolithic powder based composites; they can be manufactured by conventional powder processing techniques using inexpensive raw materials. This combination of high performance and low cost is a breakthrough that could enable wider application of ceramics in high temperature applications. Typical volume fractions of the two phases are 80 to 95% for the cell phase and 5 to 20% for the interpenetrating cell boundary phase. ACR is currently developing an innovative solid freeform form fabrication (SFF) approach to produce Hf and Zr based ceramic composite components reinforced with continuous carbon fiber tows for critical structural components such as tubes and blisks. The process is simple, robust and will be widely applicable to a number of material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The current process is being developed in collaboration with UD-CCM. The paper will detail the freeform fabrication process to create low-cost ceramic fiber reinforced composites for high-temperature applications. The results of mechanical properties and microstructural characterization will be presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts for propulsion applications at an order of magnitude lower cost than current CVI and PIP processes.

Vaidyanathan, R.↗
NASA NTRS2000

Satellite-Derived Dynamics of Southern Ocean Sea Ice

Antarctic ERS-2, RADARSAT Synthetic Aperture Radar and ERS-1/2 Scatterometer images were analyzed with SMMI radiometer image time-series data to investigate seasonal variability in satellite-tracked sea-ice dynamics in the Southern Ocean during 1992. Supporting field data were acquired during 'in-situ' experiments including the winter 1992 Ice Station Weddell and Winter Weddell Gyre studies. A variety of surface measurements were made during these experiments including Argos-buoy deployment and GPS drift measurements. These are used in conjunction with International Program for Antarctic Buoys drift trajectories for ice-motion tracking validation. Comparisons between gridded Special Sensor Microwave Imager (SSMI) ice-motion vectors and European Center for Medium Range Weather Forecasts/National Centers for Environmental Prediction (ECMWF/NCEP) analyses indicate that large-scale drift is forced predominantly by the long-term mean, large-scale synoptic pressure field. Only sub-daily SAR sea-ice tracking can capture high-frequency fluctuations, driven by polar lows or tidal forcing. In these cases, sea-ice drift can respond rapidly to changes in forcing on semi-diurnal time scales depending on the location with respect to the coastline. Seasonality of ice drift, particularly in the Weddell and Ross Seas, is linked to ice extent and compactness, and internal ice stresses transmitted through the pack ice from the coast. Three-monthly seasonal climatologies are presented of austral winter of ice drift in the Southern Ocean. The large Weddell and Ross Sea gyres are clearly resolved along with key seasonal and spatial attributes of their cyclonic circulation. Regional time series of ice dynamics parameters are used to illustrate correlations with meteorological forcing. Persistent divergence such as that occurring in the Ronne-Filchner polynya system results in large fractions of new ice. Similarly, convergence zones produce large fractions of deformed ice and characterize the dynamics of regions where perennial ice is observed. High shear strains also help delineate the axis of the Antarctic divergence in many places in the ice cover. In these regions, the separation between the coastal 'east wind drift'and ACC-dominated drift regimes is characterized by zonally extended regions of intense shear.

Drinkwater, Mark R.↗
NASA NTRS2005

Technology Challenges for Deep-Throttle Cryogenic Engines for Space Exploration

Historically, cryogenic rocket engines have not been used for in-space applications due to their additional complexity, the mission need for high reliability, and the challenges of propellant boil-off. While the mission and vehicle architectures are not yet defined for the lunar and Martian robotic and human exploration objectives, cryogenic rocket engines offer the potential for higher performance and greater architecture/mission flexibility. In-situ cryogenic propellant production could enable a more robust exploration program by significantly reducing the propellant mass delivered to low earth orbit, thus warranting the evaluation of cryogenic rocket engines versus the hypergolic bi-propellant engines used in the Apollo program. A multi-use engine. one which can provide the functionality that separate engines provided in the Apollo mission architecture, is desirable for lunar and Mars exploration missions because it increases overall architecture effectiveness through commonality and modularity. The engine requirement derivation process must address each unique mission application and each unique phase within each mission. The resulting requirements, such as thrust level, performance, packaging, bum duration, number of operations; required impulses for each trajectory phase; operation after extended space or surface exposure; availability for inspection and maintenance; throttle range for planetary descent, ascent, acceleration limits and many more must be addressed. Within engine system studies, the system and component technology, capability, and risks must be evaluated and a balance between the appropriate amount of technology-push and technology-pull must be addressed. This paper will summarize many of the key technology challenges associated with using high-performance cryogenic liquid propellant rocket engine systems and components in the exploration program architectures. The paper is divided into two areas. The first area describes how the mission requirements affect the engine system requirements and create system level technology challenges. An engine system architecture for multiple applications or a family of engines based upon a set of core technologies, design, and fabrication approaches may reduce overall programmatic cost and risk. The engine system discussion will also address the characterization of engine cycle figures of merit, configurations, and design approaches for some in-space vehicle alternatives under consideration. The second area evaluates the component-level technology challenges induced from the system requirements. Component technology issues are discussed addressing injector, thrust chamber, ignition system, turbopump assembly, and valve design for the challenging requirements of high reliability, robustness, fault tolerance, deep throttling, reasonable performance (with respect to weight and specific impulse).

Brown, Kendall K.↗
NASA NTRS2008

Gusev Crater on Mars: Wet and Dry

The Mars Exploration Rover Spirit has traversed over 7.5 km in 1470 sols of operations at the Gusev Crater landing site. Chemical and mineralogical evidence from approximately 200 in-situ samples indicate various degrees of exposure to liquid water, from wet and saturated to dry and unaltered. (1) Six samples with concentrations of amorphous silica between 60 and 95 wt% were discovered in a small valley less than 50 meters in length. Associated enrichments in titanium oxide, relatively insoluble at low pH, suggest that these silica deposits formed as a result of acidic leaching processes. Liquid water interactions with these surface materials were necessary to remove cations solubilized in the low pH environment or to concentrate silica in solution prior to precipitation. (2) Hydrated ferric sulfates are found in subsurface deposits which have the unmistakable chemical signatures of nearby rocks. The movement of hydrothermal fluids and/or fumarolic vapors through local rocks prior to precipitation of these materials is suggested by these observations. (3) Goethite (alpha-FeOOH), a mineral phase which requires water to form, represents 20% to 35% of the iron in numerous rock samples (Clovis Class) on the West Spur of the Columbia Hills. Alteration of iron under aqueous conditions is clearly indicated by this presence of goethite. (4) Nearly isochemical signatures are found in elemental analyses of over ten distinct samples (Wishstone/Watchtower class rocks), yet the ratio of ferric iron to total iron varies from 0.4 to 0.95. Small quantities of water, insufficient to flush cations from the samples, were likely responsible for this weathering. (5) Bromine, a trace element readily mobilized by water, is found in high concentrations in certain rock interiors and is enhanced in subsurface soils, consistent with transport to localized cold traps by water thin-films. (6) Also relevant to the characterizing the role of liquid water is the discovery of an areally extensive ultramafic sequence of rocks where over 70% of the iron is in unaltered olivine and the ferric to total iron ratio is 0.1. This result indicates that certain materials at the martian surface have been protected from aqueous alteration.

Yen, Albert↗
NASA NTRS2010

The Connection Between Small Gamma-Ray Flares and SEPs with COMPTEL/CGRO

While it is clear that particle acceleration is occurring during flares, what is less clear is the connection between the neutral radiation observed concommitant with the flare and the in-situ observations of SEPs. For the largest SEP events, where current instruments possess the sensitivity to observe nuclear-related gamma-ray emission, the origin of SEPs is generally divided between an escaping accelerated flare population and a population of coronal particles (or some admixture) accelerated through CME-driven shocks. Small flares, as defined by their X-ray emission, have been found to correlate with the presence of small "impulsive" (enriched in electrons and heavy nuclei) SEP events, suggesting that small SEP events are originally flare particles. The difficulty with this interpretation is that small flares lack detectable nuclear-related gamma-ray emission. Whether this emission is there or not is unclear because current instruments capable of high-energy gamma-ray observations operate above the sensitivity threshold for observing gammaray emission from small flares (< C-class). The COMPton TELescope (COMPTEL) aboard the Compton Gamma Ray Observatory (CGRO) provided unprecedented, and as yet unsurpassed, sensitivity to y rays in the 0.7 to 30 MeV energy range and neutrons in the 20 to 150 MeV energy range. This, combined with its nine years of operation, has produced a unique data set of observations for almost a complete solar cycle. The COMPTEL archival data offers the best possibility to investigate a connection between SEP observations in space and small-flare gamma-ray emission. We present preliminary results of a small-flare search within the COMPTEL archival data and discuss the correlation between already well-established compilations of SEP events and small impulsive or 3He-rich SEP events. Establishing a connection and determining the characterization of this connection, would signify an important development in our understanding of how and where flare particles are accelerated and how these very same particles escape into the interplanetary medium. Equally important would be demonstrating the inconsistencies or poor correlation between gamma-ray emission and small impulsive SEP events.

deNolfo, Georgia↗
NASA NTRS2012

DRAGONS - A Micrometeoroid and Orbital Debris Impact Sensor

The Debris Resistive/Acoustic Grid Orbital Navy Sensor (DRAGONS) is intended to be a large area impact sensor for in-situ measurements of micrometeoroids and orbital debris (MMOD) in the approx.0.2 to 1 mm size regime. These MMOD particles are too small to be detected by groundbased radars and optical telescopes, but still large enough to be a safety concern for human space activities and robotic missions in the low Earth orbit (LEO) region. The nominal detection area of DRAGONS is 1 sq m, consisting of four 0.5 m x 0.5 m independently operated panels. The concept of the DRAGONS design is to combine three different detection technologies to maximize information extracted from each detected impact. The first technology is a resistive grid consisting of 62.5-microns-wide resistive lines, coated in parallel and separated by 62.5 micron gaps on a Kapton film. When a particle a few hundred micrometers or larger strikes the grid, it world penetrate the film and sever some resistive lines. The size of the damage area can be estimated from the increased resistance. The second technology employs a dual-layer, 25-microns-thick Kapton film with a 10 cm separation. By measuring the time difference between impacts on the two films, the impact speed can be calculated. The third technology is based on polyvinylidene fluoride (PVDF) acoustic impact sensors. Multiple PVDF sensors are attached to the backside of both Kapton films to provide impact timing measurements. The impact location on each film can be identified from the triangulation of signals received at different PVDF sensors and provides an estimate of the impact direction. The development of DRAGONS is supported by the NASA Orbital Debris Program Office. The project is led by the U.S. Naval Academy (USNA), with additional collaboration from the U.S. Naval Research Laboratory (NRL), the University of Kent at Canterbury in Great Britain, and Virginia Tech (VT). The short-term goal of DRAGONS is to advance its Technology Readiness Level to 9 and to demonstrate the system capabilities of detecting and characterizing submillimeter MMOD impacts. The long-term goal is to deploy a large detection area (>1 sq m) DRAGONS to 700-1000 km altitude and collect sufficient data for better environment definition of MMOD in the 0.2- to 1-mm size regime. The Preliminary Design Review (PRD) of DRAGONS was held at the USNA in June 2012. The Critical Design Review (CDR) is scheduled for early 2013. A flight-ready unit with a 0.25 sq m detection area will be completed and tested by the end of September 2013. The biggest challenge for the project, however, is to identify a demonstration opportunity on the International Space Station in the coming years.

Liou, J. C.↗
NASA NTRS1990

Next-generation in-situ science concepts and technology

This paper discusses the concepts of a next-generation in situ science program, named Sample Acquisition, Analysis, and Preservation (SAAP), established by NASA to develop critical technologies for remote identification, acquisition, processing, analysis, and preservation of materials for the in situ science, engineering characterization, and earth return. Special attention is given to the SAAP architecture, system design, remote sensing system, sample acquisition system, and methods for sample analysis. A diagram of the SAAP preliminary system conceptual design is included.

Muirhead, Brian↗
NASA NTRS1994

Formation and eruption of Sun-aligned arcs at the polar cap-auroral oval boundary

This paper reports on results from a study of the poleward edge of the auroral oval in the morning sector using a comprehensive blend of in-situ and ground-based measurements. Three rockets, equipped to measure electric and magnetic fields, energetic particles, and plasma density flew into an auroral display whose dynamical features were reorded with a digital image into an auroral display intensified all-sky camera as well as with an incoherent scatter radar. In addition, a number of DMSP satellite measurements bracketed the launch time. Evidence is presented here that in a condition of declining magnetic activity Sun-aligned arcs are injected into the polar cap at velocities approximately 7 km/s from locations of periodic brightening along the morningside of the auroral oval. The multipoint in situ measurements allow some separation of temporal and spatial effects and strongly suggest a poleward contraction of the convention pattern of about 0.25 deg INVL in 70 s. The most equatorward of the two brightest arcs studied erupted into a region which already was characterized by strong sunward convection. The most poleward, however, pushed into a region that had been convecting in an antisunward direction at velocities exceeding 1 km/s less than 2 min earlier, and it is likely that sunward convection subsequently pertained poleward of that arc as well. We believe that these events mark the reconfiguration of the magnetosphere into a system characterized by a smaller polar cap.

Berg, G. A.↗
NASA NTRS2003

Investigating Surface Mineralogy, Alteration Processes, and Biomarkers on Mars Using Laser Raman Spectroscopy

Despite a wealth of information from past and ongoing missions to Mars, the capability to determine the mineralogy of surface materials and to connect mineralogy with lithologic characteristics that are diagnostic of the environment in which those materials formed remains inadequate. The 2003 Mars Exploration Rovers (MER) will carry a Mini-TES and a Mossbauer spectrometer, which will provide some detailed mineralogy information. For general characterization of minerals and/or biogenic phases (reduced carbon, PAHs, etc) on the surface of Mars, we have been developing a miniaturized laser Raman spectrometer for in situ analyses -- the Mars Microbeam Raman Spectrometer, MMRS. We are also developing strategies to use Raman spectroscopy as a stand-alone technique and to be used synergistically with other in situ analysis methods in future planetary missions. Through studies of Martian meteorites and terrestrial analogs, we are gaining experience of what compositional and structural information can be obtained on key mineral groups using in-situ Raman measurements. We are developing methods for determining mineral proportions in rocks or soils and identifying rock types from sets of closely spaced, rapidly acquired spectra. We are studying how weathering and alteration affect the Raman and luminescence features of minerals and rocks, and we are investigating the Raman characteristics of biogenic organisms and their remains. These studies form the scientific basis for in-situ planetary Raman spectroscopy, and they are being done in parallel with instrument development towards a flight version of the MMRS.

Alian Wang↗
NASA NTRS1994

NASA Ultra-Sensitive Miniature Accelerometer

Using micro-machined silicon technology, an ultra-sensitive miniature acce.,rometer can be constructed which meets the requirements for microgravity experiments in the space environment.Such an accelerometer will have a full scale sensitivity of 1C2 g a resolution of lC8 g, low cross axis sensitivity, and low temperature sensitivity. Mass of the device is approximately five grams and its footprint is 2 cm x 2 cm. Innovative features of the accelerometer, which are patented, are: electrostatic caging to withstand handling shock up to 150 g, in-situ calibration, in situ performance characterization, and both static and dynamic compensation. The transducer operates on a force balance principle wherein the displacement of the proof mass is monitored by measuring tunneling electron current flow between a conductive tip, and a fixed platen. The four major parts of the accelerometer are tip die, incorporating the tunneling tip and four field plates for controlling pitch and roll of the proof mass; two proof mass dies, attached to the surrounding frame by sets of four leg" springs; and a force plate die. The four parts are fuse-bonded into a complete assembly. External electrical connections are made at bond pads on the front surface of the force plate die. Materials and processes used in the construction of the transducer are compatible with volume production.

Zavracky, Paul M.↗
NASA NTRS2004

Lunar and Planetary Science XXXV: Missions and Instruments: Hopes and Hope Fulfilled

The titles in this section include: 1) Mars Global Surveyor Mars Orbiter Camera in the Extended Mission: The MOC Toolkit; 2) Mars Odyssey THEMIS-VIS Calibration; 3) Early Science Operations and Results from the ESA Mars Express Mission: Focus on Imaging and Spectral Mapping; 4) The Mars Express/NASA Project at JPL; 5) Beagle 2: Mission to Mars - Current Status; 6) The Beagle 2 Microscope; 7) Mars Environmental Chamber for Dynamic Dust Deposition and Statics Analysis; 8) Locating Targets for CRISM Based on Surface Morphology and Interpretation of THEMIS Data; 9) The Phoenix Mission to Mars; 10) First Studies of Possible Landing Sites for the Phoenix Mars Scout Mission Using the BMST; 11) The 2009 Mars Telecommunications Orbiter; 12) The Aurora Exploration Program - The ExoMars Mission; 13) Electron-induced Luminescence and X-Ray Spectrometer (ELXS) System Development; 14) Remote-Raman and Micro-Raman Studies of Solid CO2, CH4, Gas Hydrates and Ice; 15) The Compact Microimaging Spectrometer (CMIS): A New Tool for In-Situ Planetary Science; 16) Preliminary Results of a New Type of Surface Property Measurement Ideal for a Future Mars Rover Mission; 17) Electrodynamic Dust Shield for Solar Panels on Mars; 18) Sensor Web for Spatio-Temporal Monitoring of a Hydrological Environment; 19) Field Testing of an In-Situ Neutron Spectrometer for Planetary Exploration: First Results; 20) A Miniature Solid-State Spectrometer for Space Applications - Field Tests; 21) Application of Laser Induced Breakdown Spectroscopy (LIBS) to Mars Polar Exploration: LIBS Analysis of Water Ice and Water Ice/Soil Mixtures; 22) LIBS Analysis of Geological Samples at Low Pressures: Application to Mars, the Moon, and Asteroids; 23) In-Situ 1-D and 2-D Mapping of Soil Core and Rock Samples Using the LIBS Long Spark; 24) Rocks Analysis at Stand Off Distance by LIBS in Martian Conditions; 25) Evaluation of a Compact Spectrograph/Detection System for a LIBS Instrument for In-Situ and Stand-Off Detection; 26) Analysis of Organic Compounds in Mars Analog Samples; 27) Report of the Organic Contamination Science Steering Group; 28) The Water-Wheel IR (WIR) - A Contact Survey Experiment for Water and Carbonates on Mars; 29) Mid-IR Fiber Optic Probe for In Situ Water Detection and Characterization; 30) Effects of Subsurface Sampling & Processing on Martian Simulant Containing Varying Quantities of Water; 31) The Subsurface Ice Probe (SIPR): A Low-Power Thermal Probe for the Martian Polar Layered Deposits; 32) Deploying Ground Penetrating Radar in Planetary Analog Sites to Evaluate Potential Instrument Capabilities on Future Mars Missions; 33) Evaluation of Rock Powdering Methods to Obtain Fine-grained Samples for CHEMIN, a Combined XRD/XRF Instrument; 34) Novel Sample-handling Approach for XRD Analysis with Minimal Sample Preparation; 35) A New Celestial Navigation Method for Mars Landers; 36) Mars Mineral Spectroscopy Web Site: A Resource for Remote Planetary Spectroscopy.

Source record↗
NASA NTRS2004

In-Situ Measurements of Aerosol Optical Properties using New Cavity Ring-Down and Photoacoustics Instruments and Comparison with more Traditional Techniques

Carbonaceous species (BC and OC) are responsible for most of the absorption associated with aerosol particles. The amount of radiant energy an aerosol absorbs has profound effects on climate and air quality. It is ironic that aerosol absorption coefficient is one of the most difficult aerosol properties to measure. A new cavity ring-down (CRD) instrument, called Cadenza (NASA-ARC), measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. Absorption coefficient is obtained from the difference of measured extinction and scattering within the instrument. Aerosol absorption coefficient is also measured by a photoacoustic (PA) instrument (DRI) that was operated on an aircraft for the first time during the DOE Aerosol Intensive Operating Period (IOP). This paper will report on measurements made with this new instrument and other in-situ instruments during two field recent field studies. The first field study was an airborne cam;oaign, the DOE Aerosol Intensive Operating Period flown in May, 2003 over northern Oklahoma. One of the main purposes of the IOP was to assess our ability to measure extinction and absorption coefficient in situ. This paper compares measurements of these aerosol optical properties made by the CRD, PA, nephelometer, and Particle Soot Absorption Photometer (PSAP) aboard the CIRPAS Twin-Otter. During the IOP, several significant aerosol layers were sampled aloft. These layers are identified in the remote (AATS-14) as well as in situ measurements. Extinction profiles measured by Cadenza are compared to those derived from the Ames Airborne Tracking Sunphotometer (AATS-14, NASA-ARC). The regional radiative impact of these layers is assessed by using the measured aerosol optical properties in a radiative transfer model. The second study was conducted in the Caldecott Tunnel, a heavily-used tunnel located north of San Francisco, Ca. The aerosol sampled in this study was characterized by fresh automobile and diesel exhaust. Measurements from Cadenza and from an aethalometer are presented. The aethalometer is a filter-based photometer and the infrared channel is calibrated to produce a measure of BC mass loading.

Strawa, A. W.↗
NASA NTRS2011

Hyperspectral Biofilm Classification Analysis for Carrying Capacity of Migratory Birds in the South Bay Salt Ponds

Tidal marshes are highly productive ecosystems that support migratory birds as roosting and over-wintering habitats on the Pacific Flyway. Microphytobenthos, or more commonly 'biofilms' contribute significantly to the primary productivity of wetland ecosystems, and provide a substantial food source for macroinvertebrates and avian communities. In this study, biofilms were characterized based on taxonomic classification, density differences, and spectral signatures. These techniques were then applied to remotely sensed images to map biofilm densities and distributions in the South Bay Salt Ponds and predict the carrying capacity of these newly restored ponds for migratory birds. The GER-1500 spectroradiometer was used to obtain in situ spectral signatures for each density-class of biofilm. The spectral variation and taxonomic classification between high, medium, and low density biofilm cover types was mapped using in-situ spectral measurements and classification of EO-1 Hyperion and Landsat TM 5 images. Biofilm samples were also collected in the field to perform laboratory analyses including chlorophyll-a, taxonomic classification, and energy content. Comparison of the spectral signatures between the three density groups shows distinct variations useful for classification. Also, analysis of chlorophyll-a concentrations show statistically significant differences between each density group, using the Tukey-Kramer test at an alpha level of 0.05. The potential carrying capacity in South Bay Salt Ponds is estimated to be 250,000 birds.

Hsu, Wei-Chen↗