Search

Low power, robust technologies are appealing for in situ planetary science throughout the Solar System. The VAPoR (Volatile Analysis by Pyrolysis of Regolith) instrument is under development toward studying soil composition, volatiles, and trapped noble gases in the polar regions of the Moon and on the surface of other airless bodies. VAPoR will ingest a soil sample and conduct analysis by pyrolysis and time-of-flight mass spectrometry (ToF-MS). Two components of the system have been characterized in parallel development: a field-tested sample heater design and a laboratory-based time-of-flight mass spectrometer that emphasizes reduced mass and power through the use of micro- and nanotechnology. The pyrolysis field unit, vacuum-coupled to a commercial residual gas analyzer, has been used in Hawaii to analyze Mauna Kea soils. Water was detected, as were key inorganic pyrolysis products, including CO2 and SO2, and organic volatiles, including methane, benzene, toluene, and various hydrocarbon fragments. In parallel development, a laboratory reflectron time-of-flight mass spectrometer has been designed, assembled, and tested using electron impact ionization from a carbon nanotube electron gun. Preliminary testing reveals a mass resolution of 270.

From a scientist’s viewpoint a web site is one tool used to conduct research. From an artist’s viewpoint web sites are a form of visual composition. From a developer’s point of view a web site is a type of application. While web sites are a relatively new medium with a particular set of constraints, they do adhere to the same basic design principles that apply to other art forms. These design principles are the basic assumptions that affect the arrangement of elements within a composition. A successful design uses the principles and elements to achieve a visual goal in the composition. A web site designed for scientists has unique properties which are not shared by many other types of web sites. These properties influence the overall visual design of the web sites. Recently at the Institute of Geophysics and Planetary Physics at UCLA undertook a re-design of a number of its websites. In the effort, the use of visual design principles combined with the properties of a science web site were put to the test. In all, six different web sites were designed each with a difference science focus. We describe the process used to design the web sites which involve forming teams of designers, scientists and developers. We present example pages from each design and conclude with a discussion of what was learned during the process.

Information is shared within organizations and between organizations at an ever increasing rate. One system design that enables sharing in a distributed environment is a Virtual Observatory. A Virtual Observatory is built with clearly specified and standardized components. One essential component is a data model for the exchange of metadata. Well designed data models are compatible with the tenets of the ISO-11179 and ISO-20943 standards for metadata registries. Another essential component is the specification for persistent universal identifiers which are used to reference resources provided through the system. Identifiers are used both to link harvested information back to the original resource description and by services to retrieve a resource. Harvested information is maintained in a registry. To harvest information from a set of metadata it is necessary to understand the schema of the metadata. We propose an approach to the formation of universal identifiers which enables one to clearly discern the schema of the source metadata. A primary registry containing a broad set of base information exists in every Virtual Observatory. Specialized Task Oriented Registries (TOR) are typically derived from the primary registry. The schema in a TOR is often flat and items in the TOR can be managed in a similar manner to that prescribed in ISO-11179. The need for interoperability within a data environment and between data environments leads to the identification of broad-based, common attributes we call “Rosetta Attributes” which will enable general cross domain searches. Access to metadata is the final component of a Virtual Observatory. Access is provided by a registry service. A specification for a minimal registry service is presented.

The advent of the Virtual Observatory has begun an evolution in the space physics data environment. A number of nascent and discipline specific Virtual Observatories have started to emerge with an emphasis on data search and retrieval. As this new data environment takes shape an emphasis will be placed on interdisciplinary communication in attempts to address large scale and global problems. To this end we formulate the development of a query language to facilitate Virtual Observatory to Virtual Observatory communication. Furthermore, we outline the goals of such a language, how it would work and how existing community efforts can be leveraged to speed the development of this query language.

Our ability to deal with complex systems has improved through information system research which includes improved modeling (both data and system), the use of semantics and advances in distributed computing. The past decade has seen an explosion in the amount and variety of geosciences data and the emergence of true open data repositories through which scientists can freely access this data. Those data are found in thousands of repositories located around the world. Virtual observatories have been created to address the challenge of helping scientists search those repositories to find and access the required data. This challenge is been addressed by using technologies such as the Internet (with ample connectivity and bandwidth), the Web, cheap computing power, cheap storage and standards for critical components. Many scientific disciplines are developing virtual observatories. Yet some of the most compelling science questions cross multiple domains. While semantics can provide cross domain reasoning, often the first step in answering a question is determining what resources are available which may be relevant to a topic. The topic can be expressed as simple phrases or word sequences. Using a common relevance scoring method at all locations can enable a federated search across loosely coupled providers. The results of which can be organized into facets to aid the user in selecting the most promising resources with which to pursue the scientific investigation. We describe an approach to developing and deploying relevance scoring methods and faceted results in this brave new (virtual) world. We have found that a scoring method which considers both the presence of terms and the proximity of these terms relative to the order of the terms in the query improves the assessment of relevance. We call this Term Presence-Proximity (TPP) scoring and describe a method for calculating a normalized score. TPP scoring compares favorably with other scoring approaches.

International audience; The MAVEN spacecraft launched in November 2013, arrived at Mars in September 2014, and completed commissioning and began its one-Earth-year primary science mission in November 2014. The orbiter’s science objectives are to explore the interactions of the Sun and the solar wind with the Mars magnetosphere and upper atmosphere, to determine the structure of the upper atmosphere and ionosphere and the processes controlling it, to determine the escape rates from the upper atmosphere to space at the present epoch, and to measure properties that allow us to extrapolate these escape rates into the past to determine the total loss of atmospheric gas to space through time. These results will allow us to determine the importance of loss to space in changing the Mars climate and atmosphere through time, thereby providing important boundary conditions on the history of the habitability of Mars. The MAVEN spacecraft contains eight science instruments (with nine sensors) that measure the energy and particle input from the Sun into the Mars upper atmosphere, the response of the upper atmosphere to that input, and the resulting escape of gas to space. In addition, it contains an Electra relay that will allow it to relay commands and data between spacecraft on the surface and Earth.

The Neutral Mass Spectrometer (NMS) of the Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission is designed to measure the composition and variability of the tenuous lunar atmosphere. The NMS complements two other instruments on the LADEE spacecraft designed to secure spectroscopic measurements of lunar composition and in situ measurement of lunar dust over the course of a 100-day mission in order to sample multiple lunation periods. The NMS utilizes a dual ion source designed to measure both surface reactive and inert species and a quadrupole analyzer. The NMS is expected to secure time resolved measurements of helium and argon and determine abundance or upper limits for many other species either sputtered or thermally evolved from the lunar surface.

This study was conceived in an effort to understand cause and effect relationships between hyperglycemia and diabetic retinopathy. Numerous studies show that hyperglycemia leads to oxidative stress in the diabetic retinas, but the mechanisms that generate oxidative stress have not been resolved. Increased electron pressure on the mitochondrial electron transfer chain, increased generation of cytosolic NADH, and decreases in cellular NADPH have all been cited as possible sources of reactive oxygen species and nitrous oxide. In the present study, excised retinas from control and diabetic rats were exposed to euglycemic and hyperglycemic conditions. Using a microwave irradiation quenching technique to study retinas of diabetic rats in vivo, glucose, glucose-derived metabolites, and NADH oxidation/reduction status were measured. Studying excised retinas in vitro, glycolytic flux, lactate production, and tricarboxylic acid cycle flux were evaluated. Enzymatically assayed glucose 6-phosphate and fructose 6-phosphate were only slightly elevated by hyperglycemia and/or diabetes, but polyols were increased dramatically. Cytosolic NADH-to-NAD ratios were not elevated by hyperglycemia nor by diabetes in vivo or in vitro. Tricarboxylic acid cycle flux was not increased by the diabetic state nor by hyperglycemia. On the other hand, small increases in glycolytic flux were observed with hyperglycemia, but glycolytic flux was always lower in diabetic compared with control animals. An observed decrease in activity of glyceraldehyde-3-phosphate dehydrogenase may be partially responsible for slow glycolytic flux for retinas of diabetic rats. Therefore, it is concluded that glucose metabolism, downstream of hexokinase, is not elevated by hyperglycemia or diabetes. Metabolites upstream of glucose such as the sorbitol pathway (which decreases NADPH) and polyol synthesis are increased.

Two-dimensional MEMS microshutter arrays (MSA) have been fabricated at the NASA Goddard Space Flight Center (GSFC) for the James Webb Space Telescope (JWST) to enable cryogenic (~35 K) spectrographic astronomy measurements at near-infrared wavelengths. Functioning as a focal plane object selection device, the MSA is a 2D programmable aperture mask with fine resolution, high efficiency and high contrast. The MSA are close-packed silicon nitride shutters (cell size of 100 µm × 200 µm) patterned with a torsion flexure to allow their opening to 90°. A layer of magnetic material is deposited onto each shutter to permit magnetic actuation. Two electrodes are deposited, one onto each shutter and another onto the support structure side-wall, permitting electrostatic latching and 2D addressing. New techniques were developed to test MSA under mission-similar conditions (8 K ≤ T < 300 K). The 'magnetic rotisserie' has proven to be an excellent tool for rapid characterization of MSA. Tests conducted with the magnetic rotisserie method include accelerated cryogenic lifetesting of unpackaged 128 × 64 MSA and parallel measurement of the magneto-mechanical stiffness of shutters in 'pathfinder' test samples containing multiple MSA designs. Lifetest results indicate a logarithmic failure rate out to ~106 shutter actuations. These results have increased our understanding of failure mechanisms and provide a means to predict the overall reliability of MSA devices.

Constellation-X is a multi-satellite X-ray astronomy mission presently being planned for launch in the 2010 time frame. Each of four identical satellites will contain a telescope and instruments for imaging and spectroscopic analysis of hard and soft X-rays. The X-ray Microcalorimeter Spectrometer (XMS) instrument will use arrays of microcalorimeters to detect X-rays with energies from 0.2 to 6 keV. To achieve the desired energy resolution of 2 eV, the detectors will be cooled to 50 mK. The projected cooling power requirement is approximately 5 μW. In order to meet the mission lifetime requirement of 6 years (with a goal of 10 years), a mechanical cryocooler will be used to provide a heat sink for the low temperature cooler. In this paper we discuss the development of a continuous adiabatic demagnetization refrigerator (CADR) that meets the cooling requirements of the XMS instrument. The four-stage CADR presently being tested can operate continuously at 50 mK using a 4.2 K helium bath as a heat sink. Its cooling power of 6 μW at 50 mK exceeds the XMS requirement, and its peak heat rejection rate is less than 7 mW. Details of the CADR's design and operation, as well as the development program leading up to a flight-qualified instrument, are discussed.

Two-dimensional microshutter arrays (MSAs) are being developed at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST) for use as a programmable aperture mask for object selection for the Near Infrared Multiobject Spectrograph (NIRSpec). The MSAs are designed to provide high transmission efficiency for the selected objects and high on to off contrast ratio at the /spl sim/35 K operating temperature of JWST. The arrays of shutters are produced from silicon nitride membranes on a 100/spl times/200 /spl mu/m pitch. Individual shutters consist of a shutter blade of silicon nitride suspended from the shutter frame by a nitride torsion flexure. The shutters are normally closed. All shutters in the array are opened by the scanning magnetic field, and are held open by an electrostatic potential applied between the open shutters and the shutter support grid electrodes. To close the required shutters for a specific configuration, the potential between the shutter to be deselected and the support frame is set to zero, allowing the shutter to close. In this way, full random access addressing is achieved. We have produced such shutters and have demonstrated mechanical actuation and selection. Optical tests of open and closed shutters have demonstrated the required contrast for the JWST application. The MSA is a pioneering technology that provides the most capable possible multiobject spectrograph for JWST. It provides high contrast selection, high transmission efficiency, and can meet the environmental requirements for JWST.

A series of R 3 (Ga 1-x Fe x ) 5 O 12 (R=Gd, Dy, Ho; 0

Documenting successful remediation of polychlorinated biphenyl (PCB)-contaminated sediments is limited; potentially due to inadequate monitoring methods, complexities associated with the environment, and selected remedial techniques. At some sites, absence of appropriate baseline and postremoval monitoring limits proper evaluation of remedial efficacy. Accurate interpretation of interactions between media, space, time, species, lipid content, and remedial technique requires robust study design and data. This article presents baseline and postremoval data documenting reduced PCB concentrations in fish tissue, surface water, and sediment in response to the US Environmental Protection Agency (USEPA) time-critical removal action (TCRA) that was conducted at the former Bryant Mill Pond (BMP) on Portage Creek in Kalamazoo, Michigan. The BMP is part of an operable unit (OU) within the Allied Paper, Inc./Portage Creek/Kalamazoo River Superfund Site. PCBs discharged to the creek as a byproduct of carbonless copy paper recycling are the primary contaminant of concern. Paper waste residuals commonly appear as gray to light gray clays in river sediments and floodplain soils. The cleanup criterion was 10 mg/kg, with a residual PCB concentration goal of 1 mg/kg. Because the PCB-containing waste is (generally) associated with readily visible light gray clay, excavation of all visibly contaminated current or formerly impounded sediment served as a surrogate for the cleanup criteria and goal. Sediment was wet excavated and backfilled after diversion of the creek. After confirmation that PCB concentrations met cleanup criteria, the stream was diverted to the excavated side, and excavation and backfilling were completed. Overall, 146000 cubic yards of material including PCB-contaminated sediments were removed from the BMP. The long-term monitoring (LTM) program implemented by the Michigan Department of Environmental Quality (MDEQ), and historic data from a variety of sources (federal, state, and local agencies and responsible parties) provided data demonstrating TCRA effectiveness. Before TCRA, surface sediment PCB concentration in instream and formerly inundated sediment combined was 83 mg/kg (with a maximum of 700 mg/kg). Instream sediments that are more representative of fish exposures had a pre-TCRA surface weighted average concentration (SWAC) of 27 mg/kg. The post-TCRA SWAC for instream and floodplain sediments combined was 0.26 mg/kg. Average surface water concentrations at the downstream end of the BMP were reduced from 0.11 µg/L pre-TCRA to 0.0025 µg/L post-TCRA. Tissue samples for adult carp fillets decreased from 4 mg/kg pre-TCRA to 0.26 mg/kg post-TCRA; whole body white suckers from 3 mg/kg pre-TCRA to 0.1 mg/kg post-TCRA; whole body channel catfish from 39 mg/kg-L pre-TCRA to 2.6 mg/kg-L post-TCRA. Concentrations of PCBs in 2 species of resident fish (carp and white suckers), caged channel catfish, surface water, and sediment were reduced by over 1 order of magnitude within 1 year of completion, substantively accelerating natural recovery processes. A slight increase in PCB concentration was observed in both whole body suckers and adult carp fillets in the second monitoring period post-TCRA; however, these concentrations are still near an order of magnitude less than pre-TCRA concentrations and appear to be currently stable or on a slight downward trend.

We present test results of the first adiabatic demagnetization refrigerator (ADR) that produce true continuous cooling at sub-kelvin temperatures. This system uses multiple stages that operate in sequence to cascade heat from a “continuous” stage up to a heat sink. Continuous operation avoids the usual constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, and allows us to achieve much higher cooling power per unit mass. Our design goal is 10 μW of cooling at 50 mK while rejecting heat to a 6–10 K heat sink. The total cold mass is estimated to be less than 10 kg, including magnetic shielding of each stage. These parameters envelop the requirements for currently planned astronomy missions. The relatively high temperature heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long mission life and reduced complexity and cost. At present, we have assembled a three-stage ADR that operates with a superfluid helium bath. Additional work is underway to develop magnetocaloric materials that can extend its heat rejection capability up to 10 K. Design, operation and performance of the ADR are discussed.

The administration of saturating doses of insulin to the glucose perfused, working rat heart acutely increased activity of the glucose transporter 4, GLUT 4, in the plasma membrane (equilibrating extracellular glucose and intracellular [glucose]), activated glycogen synthase (stimulating the rate of glycogen synthesis), and increased mitochondrial acetyl CoA production by the pyruvate dehydrogenase multienzyme complex. Unexpectedly, insulin increased cardiac hydraulic work but decreased net glycolytic flux and O2 consumption, improving net cardiac efficiency by 28%. These improvements in physiologic performance and metabolic efficiency resulted from reduction of the mitochondrial free [NAD+]/[NADH] and oxidation of mitochondrial [coenzyme Q]/[coenzyme QH2], increasing the energy of the proton gradient between cytosolic and mitochondrial phases and leading to a doubling of the cytosolic free [sigmaATP]/[sigmaADP][sigmaPi]. The acute metabolic effects of insulin were qualitatively duplicated by addition of a ratio of 4 mM D-beta-hydroxybutyrate and 1 mM acetoacetate, and the increase in the efficiency was the same as with addition of insulin. Addition of both insulin and ketones to the glucose perfusate increased the efficiency of cardiac hydraulic work by 35%. The ability of a physiologic ratio of ketone bodies to correct most of the metabolic defects of acute insulin deficiency suggests therapeutic roles for these natural substrates during periods of impaired cardiac performance and in insulin-resistant states.

The Space Physics Archive Search and Extract (SPASE) project is an international collaboration among Heliophysics (solar and space physics) groups concerned with data acquisition and archiving. The SPASE group has simplified the search for data through the development of the SPASE Data model as a common method to describe data sets in the archives. The data model is an XML-based schema and is now in operational use. The use is expanding, but there are still other groups who could benefit from adopting SPASE. We discuss the present state of SPASE usage and how we foresee development in the future.

Five years ago NASA selected scientists at UCLA to form the Planetary Plasma Interactions (PPI) Node to help the scientific community locate, access and preserve particles and field data from planetary missions. Since planetary plasma data are varied and require expertise in many areas the PPI Node is distributed with an Outer Planets Subnode at the University of Iowa, an Inner Planets Subnode at UCLA and a Radio Astronomy Subnode at GSFC. The PPI Node has tried to serve the science community by providing them with high quality data products. It has worked with missions and individual scientists to secure the highest quality data possible and to thoroughly document it. The PPI Node has validated the data, placed it on long lasting media and made sure it was properly archived for use. So far it has prepared and archived over 1011 bytes of data and has produced 171 CD-ROMs with peer reviewed data. In so doing an efficient system has been developed to prepare and archive the data and thereby enable to steadily increase the rate at which the data are archived. Although the PPI Node produced a substantial archive during the initial five years, it has an even larger amount of work in progress. This includes preparing CD-ROM data sets with all of the Voyager, Pioneer and Ulysses data at Jupiter and Saturn. It is also completing the Pioneer Venus data restoration. The Galileo Venus archive and radio science data from Magellan will be prepared early in 1995. It is assisting the Small Bodies Node of PDS in the preparation of comet data and with the preparation of data from the comet Shoemaker-Levy 9 collision with Jupiter. Asteroid data from Gelileo will also be archived. In addition to providing the data, users have been provided with software tools to manage and read the data which are computer, operating system and data format independent. Scalable systems have been developed so that the same software used to manage and access the data for the entire PPI Node can be used by individual investigators to manage the data on a single CD-ROM thereby greatly reducing the software development effort for both the PPI Node and users. This software is delivered with the disks. The PPI Node data holdings are available over the Internet. They can be accessed through the World Wide Web (WWW) at Universal Resource Locator (URL) http://www.igpp.ucla.edu/ssc/pdsppi/Welcome.html. Users without a WWW browser can use the WWW interface by signing into the host “pdsppi.igpp.ucla. edu” as “pdsuser”.

The magnetocaloric properties of several AlxGdyFez (with x+y+z=100) ternary alloys have been determined between 2 and 300 K. Three distinct peaks in the magnetic entropy change ΔSm versus T were found: a low-temperature peak (near 10 K), an intermediate temperature peak (80–160 K), and a higher temperature peak (210 to 280 K). The low-temperature peak coincides with a field-induced antiferromagnetic-to-ferromagnetic transition; the intermediate and high temperature peaks are associated with other magnetic transitions. Above 60 K, these alloys exhibited superparamagnetic behavior and possessed enhanced ΔSm values, as predicted earlier for magnetic nanocomposites.

The purpose of the Cloud-Enabled Space Weather Platform (CESWP) project is to bring the power and flexibility of cloud computing to space weather physicists. The goal is to lower the barriers for the physicists to conduct their science. That is, to make it easier to collaborate with other scientists, develop space weather models, run simulations, produce visualizations and enable provenance. Success of the project is measured by the broad acceptance and use of the platform by the space weather science community.To deliver cloud computing and storage, infrastructure as a service, the project has built an internationally distributed cloud based on Eucalyptus [1]. To provide a graphical user interface for the physicists to interact with we selected the Groovy programming language and the Grails web framework. To construct the software we followed the Scrum agile software development methodology. This paper will report on the motivation and risks of such an undertaking. It will also report on the suitability of Eucalyptus as a cloud framework and the utility of the tools used to build an application on top of it.

New layered cuprates with the general stoichiometry Ca{sub 2+x}M{sub 2{minus}x}Cu{sub 5}O{sub 10} have been characterized for M = Nd, Gd, and Y. This paper reports these insulating phases having structures closely related to that of NaCuO{sub 2} and contain one-dimensional chains constructed from edge-sharing (CuO{sub 4}) square planes. The x-ray patterns of these ternary cuprate phases are complicated by strong reflections from both incommensurate and commensurate supercells which result from the ordering of the Ca{sup 2+} and M{sup 3+} ions in the structure. The stoichiometry range, and resultant Cu valences in these cuprates depend upon the nature of the trivalent ion. Ca-rich and trivalent-rich compositions can be prepared for M = Nd and Gd, but only Ca-rich compositions were formed in the Y system. No other ternary phases are observed under the conditions of this study, 1000{degrees}C in air, and the solid-state equilibria are dominated by the single ternary phase identified above.

Three groups of male Wistar rats were pair fed NIH-31 diets for 14 days to which were added 30% of calories as corn starch, palm oil, or R-3-hydroxybutyrate-R-1,3-butanediol monoester (3HB-BD ester). On the 14th day, animal brains were removed by freeze-blowing, and brain metabolites measured. Animals fed the ketone ester diet had elevated mean blood ketone bodies of 3.5 mm and lowered plasma glucose, insulin, and leptin. Despite the decreased plasma leptin, feeding the ketone ester diet ad lib decreased voluntary food intake 2-fold for 6 days while brain malonyl-CoA was increased by about 25% in ketone-fed group but not in the palm oil fed group. Unlike the acute effects of ketone body metabolism in the perfused working heart, there was no increased reduction in brain free mitochondrial [NAD(+)]/[NADH] ratio nor in the free energy of ATP hydrolysis, which was compatible with the observed 1.5-fold increase in brain uncoupling proteins 4 and 5. Feeding ketone ester or palm oil supplemented diets decreased brain L-glutamate by 15-20% and GABA by about 34% supporting the view that fatty acids as well as ketone bodies can be metabolized by the brain.

A new nanoscale electric field sensor was developed for studying triboelectric charging in terrestrial and Martian dust devils. The sensor was fabricated using MEMS techniques, integrated at the system level, and deployed during a dust devil field campaign. The two-terminal piezoresistive sensor consists of a micron-scale network of suspended singlewalled carbon nanotubes (SWCNTs) that are mechanically coupled to a free-standing electrically conductor. Electrostatic coupling of the conductor to the electric field is expected to produce a deflection of the conductor and a corresponding change in nanotube device resistance, based on the known piezoresistive properties of SWCNTs. The projected device performance will allow measurement of the large electric fields for large dust devils without saturation. With dimensions on the 100 μm scale and power consumption of only tens of nW, the sensor features dramatically reduced mass, power, and footprint. Recent field testing of the sensor demonstrated the robustness of suspended SWCNT devices to temperature fluctuations, mechanical shock, dust, and other environmental factors.

New layered cuprates with the general stoichiometry Ca{sub 2+x}M{sub 2{minus}x}Cu{sub 5}O{sub 10} have been characterized for M = Nd, Gd, and Y. This paper reports these insulating phases having structures closely related to that of NaCuO{sub 2} and contain one-dimensional chains constructed from edge-sharing (CuO{sub 4}) square planes. The x-ray patterns of these ternary cuprate phases are complicated by strong reflections from both incommensurate and commensurate supercells which result from the ordering of the Ca{sup 2+} and M{sup 3+} ions in the structure. The stoichiometry range, and resultant Cu valences in these cuprates depend upon the nature of the trivalent ion. Ca-rich and trivalent-rich compositions can be prepared for M = Nd and Gd, but only Ca-rich compositions were formed in the Y system. No other ternary phases are observed under the conditions of this study, 1000{degrees}C in air, and the solid-state equilibria are dominated by the single ternary phase identified above.

The lifetime of a patterned carbon nanotube film is evaluated for use as the cold cathode field emission ionization source of a miniaturized mass spectrometer. Emitted current is measured as a function of time for varying partial pressures of nitrogen gas to explore the robustness and lifetime of carbon nanotube cathodes near the expected operational voltages (70-100 eV) for efficient ionization in mass spectrometry. As expected, cathode lifetime scales inversely with partial pressure of nitrogen. Results are presented within the context of previous carbon nanotube investigations, and implications for planetary science mass spectrometry applications are discussed.

The microshutter array (MSA) is a key component in the James Webb Space Telescope Near Infrared Spectrometer (NIRSpec) instrument. The James Webb Space Telescope is the next generation of a space-borne astronomy platform that is scheduled to be launched in 2013. However, in order to effectively operate the array and meet the severe operational requirements associated with a space flight mission has placed enormous constraints on the microshutter array subsystem. This paper will present an overview and description of the entire microshutter subsystem including the microshutter array, the hybridized array assembly, the integrated CMOS electronics, mechanical mounting module and the test methodology and performance of the fully assembled microshutter subsystem. The NIRSpec is a European Space Agency (ESA) instrument requiring four fully assembled microshutter arrays, or quads, which are independently addressed to allow for the imaging of selected celestial objects onto the two 4 mega pixel IR detectors. Each microshutter array must have no more than ~8 shutters which are failed in the open mode (depending on how many are failed closed) out of the 62,415 (365x171) total number of shutters per array. The driving science requirement is to be able to select up to 100 objects at a time to be spectrally imaged at the focal plane. The spectrum is dispersed in the direction of the 171 shutters so if there is an unwanted open shutter in that row the light from an object passing through that failed open shutter will corrupt the spectrum from the intended object.

We are implementing nano- and micro-technologies to develop a miniaturized electron impact ionization mass spectrometer for planetary science. Microfabrication technology is used to fabricate the ion and electron optics, and a carbon nanotube (CNT) cathode is used to generate the ionizing electron beam. Future NASA planetary science missions demand miniaturized, low power mass spectrometers that exhibit high resolution and sensitivity to search for evidence of past and present habitability on the surface and in the atmosphere of priority targets such as Mars, Titan, Enceladus, Venus, Europa, and short-period comets. Toward this objective, we are developing a miniature, high resolution reflectron time-of-flight mass spectrometer (Mini TOF-MS) that features a low-power CNT field emission electron impact ionization source and microfabricated ion optics and reflectron mass analyzer in a parallel-plate geometry that is scalable. Charged particle electrodynamic modeling (SIMION 8.0.4) is employed to guide the iterative design of electron and ion optic components and to characterize the overall performance of the Mini TOF-MS device via simulation. Miniature (< 1000 cm3) TOF-MS designs (ion source, mass analyzer, detector only) demonstrate simulated mass resolutions > 600 at sensitivity levels on the order of 10-3 cps/molecule N2/cc while consuming 1.3 W of power and are comparable to current spaceflight mass spectrometers. Higher performance designs have also been simulated and indicate mass resolutions ~1000, though at the expense of sensitivity and instrument volume.

Solar system exploration and the anticipated discovery of biomarker molecules is driving the development of a new miniature time-of-flight (TOF) mass spectrometer (MS). Space flight science investigations become more feasible through instrument miniaturization, which reduces size, mass, and power consumption. However, miniaturization of space flight mass spectrometers is increasingly difficult using current component technology. Micro electro mechanical systems (MEMS) and nano electro mechanical systems (NEMS) technologies offer the potential of reducing size by orders of magnitude, providing significant system requirement benefits as well. Historically, TOF mass spectrometry has been limited to large separation distances as ion mass analysis depends upon the ion flight path. Increased TOF MS system miniaturization may be realized employing newly available high speed computing electronics, coupled with MEMS and NEMS components. Recent efforts at NASA Goddard Space Flight Center in the development of a miniaturized TOF mass spectrometer with integral MEMS and NEMS components are presented. A systems overview, design and prototype, MEMS silicon ion lenses, a carbon nanotube electron gun, ionization methods, as well as performance data and relevant applications are discussed.

We have developed microshutter array systems at NASA Goddard Space Flight Center for use as multi-object aperture arrays for a Near-Infrared Spectrometer (NIRSpec) instrument. The instrument will be carried on the James Webb Space Telescope (JWST), the next generation of space telescope, after the Hubble Space Telescope retires. The microshutter arrays (MSAs) are designed for the selective transmission of light from objected galaxies in space with high efficiency and high contrast. Arrays are close-packed silicon nitride membranes with a pixel size close to 100x200 μm. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with minimized stress concentration. In order to enhance optical contrast, light shields are made on each shutter to prevent light leak. Shutters are actuated magnetically, latched and addressed electrostatically. The shutter arrays are fabricated using MEMS bulk-micromachining and packaged utilizing a novel single-sided indium flip-chip bonding technology. The MSA flight system consists of a mosaic of 2 x 2 format of four fully addressable 365 x 171 arrays. The system will be placed in the JWST optical path at the focal plane of NIRSpec detectors. MSAs that we fabricated passed a series of qualification tests for flight capabilities. We are in the process of making final flight-qualified MSA systems for the JWST mission.

A cold cathode field emission electron gun (e-gun) based on a patterned carbon nanotube (CNT) film has been fabricated for use in a miniaturized reflectron time-of-flight mass spectrometer (RTOF MS), with future applications in other charged particle spectrometers, and performance of the CNT e-gun has been evaluated. A thermionic electron gun has also been fabricated and evaluated in parallel and its performance is used as a benchmark in the evaluation of our CNT e-gun. Implications for future improvements and integration into the RTOF MS are discussed.

A complex MEMS device, microshutter array system, is being developed at NASA Goddard Space Flight Center for use as an aperture array for a Near-Infrared Spectrometer (NirSpec). The instrument will be carried on the James Webb Space Telescope (JWST), the next generation of space telescope after Hubble Space Telescope retires. The microshutter arrays (MSAs) are designed for the selective transmission of light with high efficiency and high contrast. Arrays are close-packed silicon nitride membranes with a pixel size close to 100x200 mm. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with a minimized mechanical stress concentration. Light shields are made on to each shutter for light leak prevention so to enhance optical contrast. Shutters are actuated magnetically, latched and addressed electrostatically. The shutter arrays are fabricated using MEMS bulk-micromachining technologies and packaged using single-sided indium flip-chip bonding technology. The MSA flight concept consists of a mosaic of 2 x 2 format of four fully addressable 365 x 171 arrays placed in the JWST optical path at the focal plane.

Two-dimensional MEMS microshutter arrays are being developed at NASA Goddard Space Flight Center for use in the near-infrared region on the James Webb Space Telescope (JWST). The microshutter arrays are designed for the selective transmission of light with high efficiency and high contrast. The JWST environment requires cryogenic operation at 35K. Microshutter arrays are fabricated out of silicon-oxide-insulated (SOI) silicon wafers. Arrays are close-packed silicon nitride membranes with a pixel size of 100x200 p. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with a minimized mechanical stress concentration. The mechanical shutter arrays are fabricated using MEMS technologies. The processing includes a multi- layer metal deposition and patterning of shutter electrodes and magnetic pads, reactive ion etching (NE) of the front side to form shutters out of the nitride membrane, an anisotropic back-etch for wafer thinning, followed by a deep RIE (DRIE) back-etch down to the nitride shutter membrane to form W e s and relieve shutters from the silicon substrate. An additional metal deposition and patterning is used to form back electrodes. Shutters are actuated using a magnetic force and latched using an electrostatic force. . . . KEYWORDS: microshutter, MEMS, RIE, DRIE, micro-optics, near inbred, space telescope

We report on methods to minimize thermally-induced deformation in a MEMS-based reconfigurable aperture. The device is an enabling component of the Near-Infrared Spectrometer, a principle instrument on NASA’s James Webb Space Telescope. The Microshutter Array consists of 384x175 individually addressable shutters which can be magnetically rotated 90° into the plane of the array and electrostatically latched open. Each shutter is a 100x200 μm rectangular membrane suspended by a small neck region and torsion flexure. The primary materials in the shutter are a 5000a Si3N4 layer for mechanical rigidity, 2000a Al for opacity and electrostatic latching, and 2200a Co90Fe10 for magnetic actuation. This multi-layer stack presents a challenge due to the operating temperatures required for the device: both room temperature (300K) and cryogenic temperature (30K). Thermal expansion of the materials causes the shutters to bow out of plane excessively, which can prevent actuation of the shutters, cause damage to portions of the array, and allow light leakage around closed shutters. Here we present our investigation of several methods to prevent microshutter bowing including deposition of additional materials on the shutters to create a symmetrical layer stack and replacing the current stack with low-coefficient of thermal expansion materials. Using shutter-size suspended cantilever beams as a rapid-development test bed, we have reduced out-of-plane bowing between 300K and 30K to 10% or better. We are currently applying these results to microshutter arrays to develop shutters that remain flat from room temperature to cryogenic temperature while retaining the required mechanical, optical, and magnetic properties.

Micro Electromechanical System (MEMS) microshutter arrays are being developed at NASA Goddard Space Flight Center for use as a field selector of the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST). The microshutter arrays are designed for the spontaneous selection of a large number of objects in the sky and the transmission of light to the NIRSpec detector with high contrast. The JWST environment requires cryogenic operation at 35 K. Microshutter arrays are fabricated out of silicon-on-insulator (SOI) silicon wafers. Arrays are close-packed silicon nitride membranes with a pixel size of 100 x 200 μm. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with a minimized mechanical stress concentration. Light shields are processed for blocking light from gaps between shutters and frames. The mechanical shutter arrays are fabricated using MEMS technologies. The processing includes multi-layer metal depositions, the patterning of magnetic stripes and shutter electrodes, a reactive ion etching (RIE) to form shutters out of the nitride membrane, an anisotropic back-etch for wafer thinning, followed by a deep RIE (DRIE) back-etch to form mechanical supporting grids and release shutters from the silicon substrate. An additional metal deposition is used to form back electrodes. Shutters are actuated by a magnetic force and latched using an electrostatic force. Optical tests, addressing tests, and life tests are conducted to evaluate the performance and the reliability of microshutter arrays.

The Near Infrared Spectrograph (NIRSpec) for the James Webb Space Telescope (JWST) is a multi-object spectrograph operating in the 0.6-5.0 μm spectral range. One of the primary scientific objectives of this instrument is to measure the number and density evolution of galaxies following the epoch of initial formation. NIRSpec is designed to allow simultaneous observation of a large number of sources, vastly increasing the capability of JWST to carry out its objectives. A critical element of the instrument is the programmable field selector, the Microshutter Array. The system consists of four 175 x 384 close packed arrays of individually operable shutters, each element subtending 0.2” x 0.4”on the sky. This device allows simultaneous selection of over 200 candidates for study over the 3.6’ x 3.6’ field of the NIRSpec, dramatically increasing its efficiency for a wide range of investigations. Here, we describe the development, production, and test of this critical element of the NIRSpec.

Sir2 is a NAD + -dependent histone deacetylase that controls gene silencing, cell cycle, DNA damage repair, and life span. Prompted by the observation that the [NAD + ]/[NADH] ratio is subjected to dynamic fluctuations in skeletal muscle, we have tested whether Sir2 regulates muscle gene expression and differentiation. Sir2 forms a complex with the acetyltransferase PCAF and MyoD and, when overexpressed, retards muscle differentiation. Conversely, cells with decreased Sir2 differentiate prematurely. To inhibit myogenesis, Sir2 requires its NAD + -dependent deacetylase activity. The [NAD + ]/[NADH] ratio decreases as muscle cells differentiate, while an increased [NAD + ]/[NADH] ratio inhibits muscle gene expression. Cells with reduced Sir2 levels are less sensitive to the inhibition imposed by an elevated [NAD + ]/[NADH] ratio. These results indicate that Sir2 regulates muscle gene expression and differentiation by possibly functioning as a redox sensor. In response to exercise, food intake, and starvation, Sir2 may sense modifications of the redox state and promptly modulate gene expression.

The apparent equilibrium constant of the biochemical reaction, 2-propanol+NADP(ox) = acetone+NADP(red), was determined at I = 0.25 M over a wide range of pH (5.63 to 8.02) and temperature (5 to 40 degrees C). The reaction was catalyzed by an NADP-dependent alcohol dehydrogenase. The results were used to calculate thermodynamic quantities for the chemical (ionic) reference reaction: 2-propanol+NADP(ox)(3-) = acetone+NADP(red)(4-)+H(+). The thermodynamic quantities for this reference reaction are as follows: equilibrium constant K = (5.98+/-0.46) x 10(-10); standard molar Gibbs energy change Delta(r)G(0) = (52.65+/-0.19) kJmol(-1); standard molar enthalpy change Delta(r)H(0) = (38.9+/-0.6) kJmol(-1); and standard molar entropy change Delta(r)S(0) = -(46.1+/-2.2)J K(-1)mol(-1). All of these results pertain to 25 degrees C (298.15 K) and I = 0. The results also lead, in conjunction with tabulated thermodynamic quantities, to the standard electromotive force E(0) = -0.140 V for the reduction of NADP(ox)(3-) to NADP(red)(4-).

Magnetically actuated MEMS microshutter arrays are being developed at the NASA Goddard Space Flight Center for use in a multi-object spectrometer on the James Webb Space Telescope (JWST), formerly Next Generation Space Telescope (NGST). The microshutter arrays are designed for the selective transmission of light with high efficiency and high contrast. The JWST environment requires cryogenic operation at 45K. Microshutter arrays are fabricated out of silicon-on-insulator (SOI) wafers. Arrays consist of close-packed shutters made on silicon nitride (nitride) membranes with a pixel size of 100 × 100 m. Individual shutters are patterned with a torsion flexure permitting shutters to open 90°, with a minimized mechanical stress concentration. Shutters operated this way have survived fatigue life test. The mechanical shutter arrays are fabricated using MEMS technologies. The processing includes a multi-layer metal deposition, patterning of shutter electrodes and magnetic pads, reactive ion etching (RIE) of the front side to form shutters in a nitride film, an anisotropic back-etch for wafer thinning, and a deep RIE (DRIE) back-etch, down to the nitride shutter layer, to form support frames and relieve shutters from the silicon substrate. An additional metal deposition and patterning has recently been developed to form electrodes on the vertical walls of the frame. Shutters are actuated using a magnetic force, and latched electrostatically. One-dimensional addressing has been demonstrated.

In this paper we summarize recent progress in the development of an adiabatic demagnetization refrigerator (ADR) that operates continuously at sub-Kelvin temperatures. The ADR uses multiple stages, one of which cools a load while the others periodically transfer heat to a heat sink. The architecture is very flexible, allowing stages to be added at the low end to achieve lower operating temperature, or at the high end to increase the heat rejection temperature. The present design goals are to achieve high cooling power (on the order of 10 ?W) at 50 mK or lower, and heat rejection at 6 K or higher. The latter reflects the performance goals of various cryocoolers being developed for use in space through NASA’s Advanced Cryocooler Technology Development Program1. Over the past year we assembled and tested a 3-stage ADR that used a superfluid helium bath as a heat sink. We have also recently assembled a 4-stage ADR that can operate with a 4.2 K helium bath. Details of the design, operation and performance of these systems are discussed.

The design, development and operations of a distributed data inventory system is a concern of many government agencies and commercial enterprises. All are searching for ways to harness the information and data resources that are available, as well as provide a framework for bringing future data into an unifying structure. We provide a discussion of the design, development and operation of a system which can be used to build, manage and access distributed data inventories. We discuss the major decisions we made, why we made those decisions and what the end product of our efforts has been. Currently the system we describe is being used as the data access system for the Plasma Interactions Node (PDS/PPI) of NASA's Planetary Data System in order to provide access to fields and particles data returned from NASA's planetary missions. >

The development of a micro -scale tunable Fabry - Perot interferometer with narrow band pass (0.3 ∝m) and application to wide -field spectroscopy is presented. In this design, a silicon wafer is micro -machined using deep reactive ion etching (DRIE) to fabricate two etalon plates. The first etalon is a monolithic structure that includes the etalon fram e, its spring suspension, and support frame. The second is a fixed reference etalon plate. A silicon nitride membrane is suspended in tension across a thick support ring on both the moveable and fixed etalon plates as a result of back etching. Due to the processes of thin film deposition, high stresses are transmitted throughout the structure. Because of stringent flatness and parallelism requirements on the etalon plates, simulations are used to aid in the design of a suitable optical coating, which is deposited onto the membrane. Tuning the optical gap is achieved via electrostatic actuation. Simulating force - deflection behavior of the tunable etalon plate is also performed to characterize mechanical stiffness of the spring suspension system, as it det ermines electrostatic stiffness. Theoretical coupled field analysis is compared with an electrostatic simulation to predict voltage required to precisely tune the optical gap (17.5 ∝m maximum) in accordance with well -defined Fabry - Perot figures of merit. Test data gathered from three different experimental setups - nanoindentation, wave front sensing interferometry, and electrostatic actuation - correlate well with predictions based on finite element analysis.

Future NASA satellite detector systems must be cooled to the 0.1 K temperature range to meet the stringent energy resolution and sensitivity requirements demanded by mid-term astronomy missions. The development of adiabatic demagnetization refrigeration (ADR) materials that can efficiently cool from the passive radiative cooling limit of ∼30 K down to sub-Kelvin under low magnetic fields (H⩽3 T) would represent a significant improvement in space-based cooling technology. Governed by these engineering goals, our efforts have focused on quantifying the change in magnetic entropy of rare-earth garnets and perovskites. Various compositions within the gadolinium gallium iron garnet solid solution series (GGIG, Gd3Ga5−XFeXO12, 0.00⩽X⩽5.00) and gadolinium aluminum perovskite (GAP, GdAlO3) have been synthesized via an organometallic complex approach and confirmed with powder x-ray diffraction. The magnetization of the GGIG and GAP materials has been measured as a function of composition (0.00⩽X⩽5.00), temperature...

Today’s space physics data systems are faced with a vast quantity of data and researchers need to have ready access to the data. These needs are compounded by the variety of ways in which researchers do their work. One way to provide ready access to data is through a central store. Even when there is an adequate central store of the data, researchers usually require local access to the data for performance reasons. Since the volume of data which may be distributed could be large it is very beneficial to distribute a data system with the data. Since system resources vary from researcher to researcher a data system must be scalable to the size of the resources on the system.Developers and researchers at the Planetary Plasma Interactions (PPI) Node of the Planetary Data System (PDS) have addressed this problem and have designed and implemented a scalable data system which uses incremental data sets. This system allows collections of data to be brought on‐line from archival media and merged with other collect...

Scientific data preparation is the process of extracting usable scientific data from raw instrument data. This task involves noise detection (and subsequent noise classification and flagging or removal), extracting data from compressed forms, and construction of derivative or aggregate data (e.g., spectral densities or running averages).This paper describes the PIPE system. PIPE provides intelligent assistance developing scientific data preparation plans developed using Master Plumber, a general language for scientific data processing plans. PIPE provides this assistance capability by using a process description to create a dependency model of the scientific data preparation plan. This dependency model can then be used to verify syntactic and semantic constraints on processing steps to perform limited plan validation. PIPE also provides capabilities for using this model to assist in debugging faulty data preparation plans. In this case, the process model is used to focus the developers’ attention upon tho...

Members of the Planetary Plasma Interactions Node of the Planetary Data System (PDS/PPI) have designed and implemented a data system which allows for distributed access to centralized data, centralized access to distributed data, and distributed access to distributed data. While these types of data access might seem like completely different problems, they are not. The only differences are the number of access pathways to and from the data. By adopting a client/server model of system design we have been able to provide transparent access to both distributed and centralized data. In addition, by carefully choosing the location of the division between the client and server, the response of the system as a whole can be greatly enhanced. For example, the user interface is a stand‐alone application which configures itself according to information stored with the data sets and the data sets may be local or distributed. All keystroke interactions are handled on the local machine and the end results of menu selec...

The management of large databases can be a time consuming and tedious task without tools to automate the process. In order to facilitata the process, a database design philosophy which is consistent with application objectives must be adopted. The Planetary Plasma Interactions (PPI) Node of the Planetary Data System (PDS) provides users with a software application which allows for rapid retrieval (for examination or extraction) of datasets which are distributed and which may exist in more than one location simultaneously. In addition, the application software, which interacts with both a local and a centralized database management system (dbms) via a client‐server architecture, also is distributed. The basic problem lies in keeping all of the information current in a dynamic data environment so that the application software, regardless of its location, can access any data in the system with the greatest possible throughput. In addressing this problem the PDS/PPI Node has adopted a standardized architecture [2] and has chosen to package data management information with the data themselves as a set of detached relational flatfiles. At the PDS/PPI Node automated dbms tools are being developed which update both local and central management systems by using the information provided along with the datasets. This information can be stored in any relational database system or it can be accessed and manipulated outside of a dbms. Science data are not maintained under direct dbms control.