Science.gov

Sample records for acid tetrahydrate sat

  1. Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

    2011-01-01

    We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

  2. Heterogeneous Interactions of ClONO2 and HCl with Sulfuric Acid Tetrahydrate: Implications for the Stratosphere

    NASA Technical Reports Server (NTRS)

    Zhang, Renyi; Jayne, John T.; Molina, Mario J.

    1994-01-01

    The reaction probabilities for ClONO2+H2O- HOCl + HNO3 and ClONO2+ HCl Cl2 +HNO3 have been investigated on sulfuric acid tetrahydrate (SAT, H2SO4-4H2O)surfaces at temperatures between 190 and 230 K and at reactant concentrations that are typical in the lower stratosphere, using a fast-flow reactor coupled to a quadrupole mass spectrometer. The results indicate that the reaction probabilities as well as HCl uptake depend strongly on the thermodynamic state of SAT surface: they decrease significantly with decreasing H2O partial pressure at a given temperature, and decrease with increasing temperature at a given H2O partial pressure, as the SAT changes from the H2O-rich form to the H2SO4-rich form. For H2O-rich SAT at 195 K gamma(sub 1) approx. = -0.01 and gamma(sub 2) greater or equal to 0.1, whereas the values for H2SO4-rich SAT decrease by more than 2 orders of magnitude. At low concentrations of HCl, close to those found in the stratosphere, the amount of HCl taken up by H2O-rich SAT films corresponds to a coverage of the order of a tenth of a monolayer (approx. = 10(exp 14) molecules/sq cm); H2SO4-rich SAT films take up 2 orders of magnitude less HCl (les than 10(exp 12) molecules/sq cm). Substantial HCl uptake at high HCl concentrations is also observed, as a result of surface melting. The data reveal that frozen stratospheric sulfate aerosols may play an important role in chlorine activation in the winter polar stratosphere via processes similar to those occurring on the surfaces of polar stratospheric cloud particles.

  3. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  4. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  5. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  6. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  7. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  8. In vivo percutaneous absorption of boron as boric acid, borax, and disodium octaborate tetrahydrate in humans: a summary.

    PubMed

    Wester, R C; Hui, X; Maibach, H I; Bell, K; Schell, M J; Northington, D J; Strong, P; Culver, B D

    1998-01-01

    Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry, which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax, and disodium octaborate tetrahydrate (DOT) in biological matrices. This made it possible, in the presence of comparatively large natural dietary boron intakes for the in vivo segment of this study, to quantify the boron passing through skin. Human volunteers were dosed with 10B-enriched boric acid, 5.0%, borax, 5.0%, or disodium octaborate tetrahydrate, 10% in aqueous solutions. Urinalysis, for boron and changes in boron isotope ratios, was used to measure absorption. Boric acid in vivo percutaneous absorption was 0.226 (SD = 0.125) mean percent dose, with flux and permeability constant (Kp) calculated at 0.009 microg/cm2/h and 1.9 x 10(-7) cm/h, respectively. Borax absorption was 0.210 (SD = 0.194) mean percent dose, with flux and Kp calculated at 0.009 microg/cm2/h and 1.8 x 10(-7) cm/h, respectively. DOT absorption was 0.122 (SD = 0.108) mean percent, with flux and Kp calculated at 0.01 microg/cm2/h and 1.0 x 10(-7) cm/h, respectively. Pretreatment with the potential skin irritant 2% sodium lauryl sulfate had no effect on boron skin absorption. These in vivo results show that percutaneous absorption of boron, as boric acid, borax, and disodium octaborate tetrahydrate, through intact human skin is low and is significantly less than the average daily dietary intake. This very low boron skin absorption makes it apparent that, for the borates tested, the use of gloves to prevent systemic uptake is unnecessary. These findings do not apply to abraded or otherwise damaged skin.

  9. In vitro percutaneous absorption of boron as boric acid, borax, and disodium octaborate tetrahydrate in human skin: a summary.

    PubMed

    Wester, R C; Hartway, T; Maibach, H I; Schell, M J; Northington, D J; Culver, B D; Strong, P L

    1998-01-01

    Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax and disodium octaborate tetrahydrate (DOT) in biological matrices. In vitro human skin percent doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 microg/cm2/h, and permeability constants (Kp) of 5.0 x 10(-4), 1.2 x 10(-4), and 2.9 x 10(-4) cm/h for the 0.05%, 0.5%, and 5.0% solutions. The above in vitro doses were at infinite, 1000 microL/cm2 volume. At 2 microL/cm2 (the in vivo dosing volume), flux decreased some 200-fold to 0.07 microg/cm2/h and Kp of 1.4 x 10(-6) cm/h, while percent dose absorbed was 1.75%. Borax dosed at 5.0%/1000 microL/cm2 had 0.41 percent dose absorbed, flux at 8.5 microg/cm2/h, and Kp was 1.7 x 10(-4) cm/h. Disodium octaborate tetrahydrate (DOT) dosed at 10%/1000 microL/cm2 was 0.19 percent dose absorbed, flux at 7.9 microg/cm2/h, and Kp was 0.8 x 10(-4) cm/h. These in vitro results from infinite doses (1000 microL/cm2) were a 1000-fold greater than those obtained in the companion in vivo study. The results from the finite (2 microL/cm2) dosing were closer (10-fold difference) to the in vivo results. General application of infinite dose percutaneous absorption values for risk assessment is questioned by these results.

  10. In vivo percutaneous absorption of boric acid, borax, and disodium octaborate tetrahydrate in humans compared to in vitro absorption in human skin from infinite and finite doses.

    PubMed

    Wester, R C; Hui, X; Hartway, T; Maibach, H I; Bell, K; Schell, M J; Northington, D J; Strong, P; Culver, B D

    1998-09-01

    Literature from the first half of this century report concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax, and disodium octaborate tetrahydrate (DOT) in biological matrices. This made it possible, in the presence of comparatively large natural dietary boron intakes for the in vivo segment of this study, to quantify the boron passing through skin. Human volunteers were dosed with 10B-enriched boric acid, 5.0%, borax, 5.0%, or disodium octaborate tetrahydrate, 10%, in aqueous solutions. Urinalysis, for boron and changes in boron isotope ratios, was used to measure absorption. Boric acid in vivo percutaneous absorption was 0.226 (SD = 0.125) mean percentage dose, with flux and permeability constant (Kp) calculated at 0.009 microgram/cm2/h and 1.9 x 10(-7) cm/h, respectively. Borax absorption was 0.210 (SD = 0.194) mean percentage of dose, with flux and Kp calculated at 0.009 microgram/cm2/h and 1.8 x 10(-7) cm/h, respectively. DOT absorption was 0.122 (SD = 0.108) mean percentage, with flux and Kp calculated at 0.01 microgram/cm2/h and 1.0 x 10(-7) cm/h, respectively. Pretreatment with the potential skin irritant 2% sodium lauryl sulfate had no effect on boron skin absorption. In vitro human skin percentage of doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 micrograms/cm2/h and permeability constants (Kp) of 5.0 x 10(-4), 1.2 x 10(-4), and 2.9 x 10(-4) cm/h for the 0.05, 0.5, and 5.0% solutions. The above in vitro doses were at infinite, 1000 microliters/cm2 volume. At 2 microliters/cm2 (the in vivo dosing volume), flux decreased some

  11. Growth of nitric acid hydrates on thin sulfuric acid films

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  12. Analysis of SAT Type Foot-And-Mouth Disease Virus Capsid Proteins and the Identification of Putative Amino Acid Residues Affecting Virus Stability

    PubMed Central

    Maree, Francois F.; Blignaut, Belinda; de Beer, Tjaart A. P.; Rieder, Elizabeth

    2013-01-01

    Foot-and-mouth disease virus (FMDV) initiates infection by adhering to integrin receptors on target cells, followed by cell entry and disassembly of the virion through acidification within endosomes. Mild heating of the virions also leads to irreversible dissociation into pentamers, a characteristic linked to reduced vaccine efficacy. In this study, the structural stability of intra- and inter-serotype chimeric SAT2 and SAT3 virus particles to various conditions including low pH, mild temperatures or high ionic strength, was compared. Our results demonstrated that while both the SAT2 and SAT3 infectious capsids displayed different sensitivities in a series of low pH buffers, their stability profiles were comparable at high temperatures or high ionic strength conditions. Recombinant vSAT2 and intra-serotype chimeric viruses were used to map the amino acid differences in the capsid proteins of viruses with disparate low pH stabilities. Four His residues at the inter-pentamer interface were identified that change protonation states at pH 6.0. Of these, the H145 of VP3 appears to be involved in interactions with A141 in VP3 and K63 in VP2, and may be involved in orientating H142 of VP3 for interaction at the inter-pentamer interfaces. PMID:23717387

  13. Analysis of SAT type foot-and-mouth disease virus capsid proteins and the identification of putative amino acid residues affecting virus stability.

    PubMed

    Maree, Francois F; Blignaut, Belinda; de Beer, Tjaart A P; Rieder, Elizabeth

    2013-01-01

    Foot-and-mouth disease virus (FMDV) initiates infection by adhering to integrin receptors on target cells, followed by cell entry and disassembly of the virion through acidification within endosomes. Mild heating of the virions also leads to irreversible dissociation into pentamers, a characteristic linked to reduced vaccine efficacy. In this study, the structural stability of intra- and inter-serotype chimeric SAT2 and SAT3 virus particles to various conditions including low pH, mild temperatures or high ionic strength, was compared. Our results demonstrated that while both the SAT2 and SAT3 infectious capsids displayed different sensitivities in a series of low pH buffers, their stability profiles were comparable at high temperatures or high ionic strength conditions. Recombinant vSAT2 and intra-serotype chimeric viruses were used to map the amino acid differences in the capsid proteins of viruses with disparate low pH stabilities. Four His residues at the inter-pentamer interface were identified that change protonation states at pH 6.0. Of these, the H145 of VP3 appears to be involved in interactions with A141 in VP3 and K63 in VP2, and may be involved in orientating H142 of VP3 for interaction at the inter-pentamer interfaces.

  14. 21 CFR 522.1075 - Gonadorelin diacetate tetrahydrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gonadorelin diacetate tetrahydrate. 522.1075 Section 522.1075 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  15. 21 CFR 522.1075 - Gonadorelin diacetate tetrahydrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gonadorelin diacetate tetrahydrate. 522.1075 Section 522.1075 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  16. 21 CFR 522.1078 - Gonadorelin diacetate tetrahydrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gonadorelin diacetate tetrahydrate. 522.1078 Section 522.1078 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  17. 21 CFR 522.1078 - Gonadorelin diacetate tetrahydrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gonadorelin diacetate tetrahydrate. 522.1078 Section 522.1078 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  18. 21 CFR 522.1078 - Gonadorelin diacetate tetrahydrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gonadorelin diacetate tetrahydrate. 522.1078 Section 522.1078 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  19. Thorium aspartate tetrahydrate precursor to ThO2: Comparison of hydrothermal and thermal conversions

    NASA Astrophysics Data System (ADS)

    Clavier, N.; Maynadié, J.; Mesbah, A.; Hidalgo, J.; Lauwerier, R.; Nkou Bouala, G. I.; Parrès-Maynadié, S.; Meyer, D.; Dacheux, N.; Podor, R.

    2017-04-01

    The synthesis of original crystalline thorium aspartate tetrahydrate, Th(C4NO4H6)4.4H2O, was performed using two different wet-chemistry routes, involving either L-asparagine or L-aspartic acid as complexing agent. Characterization of this compound through 13C NMR and PXRD led to confirm the terminal coordination mode of the aspartate group and to suggest a potential cubic lattice (Pn-3 space group). Vibrational spectroscopy data were also collected. The conversion of thorium aspartate tetrahydrate into thorium dioxide was further performed through classical high temperature heat treatment or under hydrothermal conditions. On the one hand, thermal treatment provided a pseudomorphic conversion which retained the starting morphology, and favored the increase of the average crystallite size, as well as the complete elimination of the residual carbon content. On the other, hydrothermal conversion could be used to tune the morphology of the final oxide, ThO2.nH2O microspheres being prepared when starting from L-asparagine.

  20. Was Bijvoet right? Sodium rubidium (+)-tartrate tetrahydrate revisited.

    PubMed

    Lutz, Martin; Schreurs, Antoine M M

    2008-08-01

    The first determination of the absolute configuration of an organic compound was published in 1951 on sodium rubidium (+)-tartrate tetrahydrate, Na(+).Rb(+).C(4)H(4)O(6)(2-).4H(2)O, but the atomic coordinates are not available in the public literature. This structure has therefore been redetermined using current equipment. The most up-to-date techniques for the determination of the absolute configuration have been applied and the question posed in the title can be answered with an unequivocal 'yes'.

  1. Hydrogen bonding Part 38. IR and thermodynamic study of phosphorylcholine chloride calcium salt tetrahydrate and monohydrate

    NASA Astrophysics Data System (ADS)

    Harmon, Kenneth M.; Akin, Anne C.

    1991-09-01

    Vapor pressure vs. H 2O content studies demonstrate that phosphorylcholine chloride calcium salt forms two hydrates, a monohydrate and a tetrahydrate, in the range 0-4 mol H 20 mol -1 of salt; there is no dihydrate or trihydrate. Equilibrium vapor pressure measurements show that ΔH 0 of dissociation per mol H 20 lost is greater for the tetrahydrate (16.08 kcal mol -1) than for the monohydrate (12.49 kcal mo -1); the lower stability of the tetrahydrate arises from entropy effects. The IR spectrum of the tetrahydrate is that of a framework clathrate hydrate and suggests that the -P0 3 group may act as a very weak hydrogen-bond acceptor. In the monohydrate the -P0 3 group is not involved in hydrogen bonding. Neither hydrate contains POH bonds.

  2. SmallSat Lab

    DTIC Science & Technology

    2014-03-05

    CubeSat. Mr. Alvarez worked with four students on the PCB layout for the solar panels and the construction of the 6U CubeSat mockup . Support for Mr...Hull and Mr. Alvarez was $49k including fringe benefits. !! Purchases: During this time period a license for MatLab software and the Princeton...Satellite ToolBox was purchased using funds from this award. This software adds tremendous capability to the SmallSat Lab by enabling students to analyze

  3. SmallSat Database

    NASA Technical Reports Server (NTRS)

    Petropulos, Dolores; Bittner, David; Murawski, Robert; Golden, Bert

    2015-01-01

    The SmallSat has an unrealized potential in both the private industry and in the federal government. Currently over 70 companies, 50 universities and 17 governmental agencies are involved in SmallSat research and development. In 1994, the U.S. Army Missile and Defense mapped the moon using smallSat imagery. Since then Smart Phones have introduced this imagery to the people of the world as diverse industries watched this trend. The deployment cost of smallSats is also greatly reduced compared to traditional satellites due to the fact that multiple units can be deployed in a single mission. Imaging payloads have become more sophisticated, smaller and lighter. In addition, the growth of small technology obtained from private industries has led to the more widespread use of smallSats. This includes greater revisit rates in imagery, significantly lower costs, the ability to update technology more frequently and the ability to decrease vulnerability of enemy attacks. The popularity of smallSats show a changing mentality in this fast paced world of tomorrow. What impact has this created on the NASA communication networks now and in future years? In this project, we are developing the SmallSat Relational Database which can support a simulation of smallSats within the NASA SCaN Compatability Environment for Networks and Integrated Communications (SCENIC) Modeling and Simulation Lab. The NASA Space Communications and Networks (SCaN) Program can use this modeling to project required network support needs in the next 10 to 15 years. The SmallSat Rational Database could model smallSats just as the other SCaN databases model the more traditional larger satellites, with a few exceptions. One being that the smallSat Database is designed to be built-to-order. The SmallSat database holds various hardware configurations that can be used to model a smallSat. It will require significant effort to develop as the research material can only be populated by hand to obtain the unique data

  4. Active CryoCubeSat

    NASA Technical Reports Server (NTRS)

    Swenson, Charles

    2016-01-01

    The Active CryoCubeSat project will demonstrate an advanced thermal control system for a 6-Unit (6U) CubeSat platform. A miniature, active thermal control system, in which a fluid is circulated in a closed loop from thermal loads to radiators, will be developed. A miniature cryogenic cooler will be integrated with this system to form a two-stage thermal control system. Key components will be miniaturized by using advanced additive manufacturing techniques resulting in a thermal testbed for proving out these technologies. Previous CubeSat missions have not tackled the problem of active thermal control systems nor have any past or current CubeSat missions included cryogenic instrumentation. This Active CryoCubeSat development effort will provide completely new capacities for CubeSats and constitutes a major advancement over the state-of-the-art in CubeSat thermal control.

  5. Disodium octaborate tetrahydrate treatments to slash pine for protection against formosan subterranean termite and eastern subterranean termite (isoptera: rhinotermitidae)

    SciTech Connect

    Mauldin, J.K.; Kard, B.M.

    1996-06-01

    Minimum retentions of disodium octaborate tetrahydrate (DOT) needed in slash pine, Pinus elliottii Engelm. variety elliottii, wood to provide maximum protection against 2 species of subterranean termites were determined in choice and no-choice laboratory tests. Efficacy criteria for DOT were greater or equal to 90% termite mortality and equal to or less than 5% loss in weight of treated wooden blocks. For termites fed only DOT-treated wood, 0.10 and 0.30% boric acid equivalent (BAE, percentage of boric acid based on dry weight of wood, assuming all boron is present as boric acid) protected wood from the eastern subterranean termite, Reticulitermes flavipes (Kollar), and Formosan subterranean termite, Coptotermes formosanus Shiraki, respectively. When termites had a choice between treated or nontreated wooden blocks were not in contact with soil or exposed to rain, a BAE of 0.30% protected the wood from naturally occuring Reticulitermes sp. for 18 mo. In wooden structures under constant pressure from subterranean termites, concentrations greater than 0.54% BAE may be required to protect wood, especially against C. formosanus.

  6. CubeSat Launch Initiative

    NASA Technical Reports Server (NTRS)

    Higginbotham, Scott

    2016-01-01

    The National Aeronautics and Space Administration (NASA) recognizes the tremendous potential that CubeSats (very small satellites) have to inexpensively demonstrate advanced technologies, collect scientific data, and enhance student engagement in Science, Technology, Engineering, and Mathematics (STEM). The CubeSat Launch Initiative (CSLI) was created to provide launch opportunities for CubeSats developed by academic institutions, non-profit entities, and NASA centers. This presentation will provide an overview of the CSLI, its benefits, and its results.

  7. The TechSAT program

    NASA Astrophysics Data System (ADS)

    Shachar, M.; Lapid, P.

    1992-12-01

    The TechSAT project is described which is intended to establish a wide academic infrastructure for the development of new space technologies. A TechSAT satellite will be used for educational purposes by the academic staff and students as well as by radio amateurs. Tech SAT is a microsatellite weighing 50 kg with 45x45x45 cm dimensions. It is based on a Nadir pointing 3D stabilized platform with body mounted solar panels. The TechSAT hardware includes an autonomous attitude control system, a power supply system, and an onboard computer. Command control and telemetry systems will be based on the amateur radio communications payload.

  8. Synthesis, characterization and thermal behavior of tetrakis(melamine2+) bis(melamine+) pentakis(monohydrogenphosphate) tetrahydrate

    NASA Astrophysics Data System (ADS)

    Youcef, Hakima Ait; Chafaa, Salah; Doufnoune, Rachida; Douadi, Tahar

    2016-11-01

    A new organic-inorganic salt, tetrakis (2,4,6-triamino-1,3,5-triazin-1,3-diium) bis (2,4,6-triamino-1,3,5-triazin-1-ium) pentakis (monohydrogenphosphate) tetrahydrate, 4C3H8N6+2. 2C3H7N6+. 5HPO42-. 4H2O was synthesized through the reaction of melamine and phosphoric acid in an acidic medium HCl/H2O. It was then characterized by X-ray diffraction. The title compound crystallizes in monoclinic system with non-centrosymetric space group P 21 with lattice parameters a = 11.3008 Å, b = 20.9798 Å, c = 12.2679 Å, α = 90°, β = 117.236°, γ = 90°, Z = 2 and V = 2586.10 (Å)3. The UV-vis absorption spectrum UV-vis showed that the crystal has a good optical transmittance in the entire visible region with a lower cut off wavelength of 290 nm. The vibrational frequencies of various functional groups present in the crystal were identified by FT-IR analysis. The chemical structure of the compound was also confirmed by 1H, 13C and 31P NMR spectroscopy. TGA-DTA analysis revealed that the materials have a good thermal stability without any melting.

  9. Crystal structure and hydrogen bonding in the water-stabilized proton-transfer salt brucinium 4-amino-phenyl-arsonate tetra-hydrate.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2016-05-01

    In the structure of the brucinium salt of 4-amino-phenyl-arsonic acid (p-arsanilic acid), systematically 2,3-dimeth-oxy-10-oxostrychnidinium 4-amino-phenyl-ar-son-ate tetra-hydrate, (C23H27N2O4)[As(C6H7N)O2(OH)]·4H2O, the brucinium cations form the characteristic undulating and overlapping head-to-tail layered brucine substructures packed along [010]. The arsanilate anions and the water mol-ecules of solvation are accommodated between the layers and are linked to them through a primary cation N-H⋯O(anion) hydrogen bond, as well as through water O-H⋯O hydrogen bonds to brucinium and arsanilate ions as well as bridging water O-atom acceptors, giving an overall three-dimensional network structure.

  10. SpinSat Mission Overview

    DTIC Science & Technology

    2013-09-01

    Nitinol antennae are stowed in a shallow groove along the equator of SpinSat. Each antenna is 7.5” long from the tip to the surface of SpinSat and is...antenna material is made of nitinol , a flexible metal alloy that can maintain a straight shape and can be stowed with tight bends. The antennas will be

  11. Infrared studies of sulfuric acid and its impact on polar and global ozone

    NASA Astrophysics Data System (ADS)

    Iraci, Laura Tracy

    Sulfuric acid aerosols are present throughout the lower stratosphere and play an important role in both polar and global ozone depletion. In the polar regions, stratospheric sulfate aerosols (SSAs) act as nuclei for the growth of polar stratospheric clouds (PSCs). Heterogeneous reactions can occur on these PSCs, leading to chlorine activation and catalytic ozone destruction. This thesis addresses the issue of polar ozone depletion through laboratory studies which examine the nucleation of PSCs on sulfuric acid. In addition, chemistry which occurs directly on sulfate aerosols may impact ozone at midlatitudes, and studies describing one such reaction are presented as well. To study the growth of type I PSCs on sulfuric acid, thin H2SO4 films were exposed to water and nitric acid vapors at stratospheric temperatures. Fourier transform infrared spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films which condensed. Supercooled liquid sulfuric acid films showed uptake of HNO3 to form ternary solutions, followed by crystallization of nitric acid trihydrate (NAT). When crystalline sulfuric acid tetrahydrate (SAT) films were exposed to nitric acid and water, condensation of a supercooled HNO3/H2O layer was often observed. As predicted by theory, some of the SAT crystal then dissolved, creating a ternary H2SO4/HNO3/H2O solution. From this solution, NAT nearly always crystallized, halting the phase change of sulfuric acid. If a supercooled nitric acid layer did not condense on frozen sulfuric acid, crystalline NAT was not deposited from the gas phase when SNAT/leq41. At significantly higher supersaturations, NAT could be forced to condense on sulfuric acid, regardless of its phase. Calculations of the contact parameter from experimental data indicate that m<0.79 for NAT on SAT, predicting a significant barrier to nucleation of NAT from the gas phase. While PSCs can form only in the cold polar regions of the stratosphere, sulfuric

  12. SATS HVO Concept Validation Experiment

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria; Williams, Daniel; Murdoch, Jennifer; Adams, Catherine

    2005-01-01

    A human-in-the-loop simulation experiment was conducted at the NASA Langley Research Center s (LaRC) Air Traffic Operations Lab (ATOL) in an effort to comprehensively validate tools and procedures intended to enable the Small Aircraft Transportation System, Higher Volume Operations (SATS HVO) concept of operations. The SATS HVO procedures were developed to increase the rate of operations at non-towered, non-radar airports in near all-weather conditions. A key element of the design is the establishment of a volume of airspace around designated airports where pilots accept responsibility for self-separation. Flights operating at these airports, are given approach sequencing information computed by a ground based automated system. The SATS HVO validation experiment was conducted in the ATOL during the spring of 2004 in order to determine if a pilot can safely and proficiently fly an airplane while performing SATS HVO procedures. Comparative measures of flight path error, perceived workload and situation awareness were obtained for two types of scenarios. Baseline scenarios were representative of today s system utilizing procedure separation, where air traffic control grants one approach or departure clearance at a time. SATS HVO scenarios represented approaches and departure procedures as described in the SATS HVO concept of operations. Results from the experiment indicate that low time pilots were able to fly SATS HVO procedures and maintain self-separation as safely and proficiently as flying today's procedures.

  13. NASA Facts: SporeSat

    NASA Technical Reports Server (NTRS)

    Martinez, Andres; Cappuccio, Gelsomina; Tomko, David

    2013-01-01

    SporeSat is an autonomous, free-flying three-unit (3U) spacecraft that will be used to conduct scientific experiments to gain a deeper knowledge of the mechanisms of plant cell gravity sensing. SporeSat is being developed through a partnership between NASAs Ames Research Center and the Department of Agricultural and Biological Engineering at Purdue University. Amani Salim and Jenna L. Rickus are the Purdue University Principal Investigators. The SporeSat mission will be flown using a 3U nanosatellite weighing approximately 12 pounds and measuring 14 inches long by 4 inches wide by 4 inches tall. SporeSat will utilize flight-proven spacecraft technologies demonstrated on prior Ames nanosatellite missions such as PharmaSat and OrganismOrganic Exposure to Orbital Stresses (OOREOS) as well as upgrades that increase the hardware integration capabilities with SporeSat science instrumentation. In addition, the SporeSat science payload will serve as a technology platform to evaluate new microsensor technologies for enabling future fundamental biology missions.

  14. COLD-SAT dynamic model

    NASA Technical Reports Server (NTRS)

    Adams, Neil S.; Bollenbacher, Gary

    1992-01-01

    This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

  15. DebriSat Project Update and Planning

    NASA Technical Reports Server (NTRS)

    Sorge, M.; Krisko, P. H.

    2016-01-01

    DebriSat Reporting Topics: DebriSat Fragment Analysis Calendar; Near-term Fragment Extraction Strategy; Fragment Characterization and Database; HVI (High-Velocity Impact) Considerations; Requirements Document.

  16. EMC Test Report: StangSat - CubeSat Program

    NASA Technical Reports Server (NTRS)

    Carmody, Lynne M.; Aragona, Peter S.

    2013-01-01

    This report documents the Electromagnetic Interference E M I testing performed on the StangSat; the unit under test (UUT). Testing was per the requirements of MIL STD-461F. The UUT was characterized and passed the radiated emissions (RE102 limit for Spacecraft) testing.

  17. NPS CubeSat Launcher Program Management

    DTIC Science & Technology

    2009-09-01

    the United States; NASA’s GeneSat-1 launched on a Minotaur -1 out of Wallops Island, VA in December 2006. As of the date of this thesis, only four...CubeSats have been launched from the U.S. this year: PharmaSat, CP6, AeroCube-3, HawkSat-1, also on a Minotaur -I out of Wallops Island. This is

  18. Beating the SAT: Playing the Game.

    ERIC Educational Resources Information Center

    Wiggins, James D.

    1992-01-01

    Conducted workshop for high school seniors, 50 of whom had taken Preliminary Scholastic Aptitude Test (PSAT) and 50 of whom had taken Scholastic Aptitude Test (SAT). After completion of six-hour program on application of game-playing strategies to SAT, both retakers and first-time takers of SAT (who had previously taken PSAT) raised their scores…

  19. Computer Coaching for the SAT.

    ERIC Educational Resources Information Center

    Owens, Peter

    1983-01-01

    Three computer software packages from Krell, Borg-Warner, and Edu-ware are reviewed in terms of their improving users' vocabulary, verbal analogy, and mathematical skills in preparation for the SATs. Students benefitting most are those who know the subject but do poorly on tests. (MBR)

  20. Independent Schools and the SAT

    ERIC Educational Resources Information Center

    Torres, Amada

    2016-01-01

    In September 2015, when the College Board released its average SAT scores for the 2015 graduating class, two details stood out for many educators: (1) the record participation and diversity numbers (close to 1.7 million students took the test, with 50 percent being students of color); and (2) the test's lower average scores compared with previous…

  1. SAT Future: Alignment to Standards

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    One of the chief architects of the Common Core State Standards was named the next president of the College Board and said one of his top priorities is to reshape the organization's influential college-admissions test, the SAT, to better reflect the new standards. David Coleman will assume his new duties on Oct. 15, replacing Gaston Caperton, who…

  2. Tensor Network Contractions for #SAT

    NASA Astrophysics Data System (ADS)

    Biamonte, Jacob D.; Morton, Jason; Turner, Jacob

    2015-09-01

    The computational cost of counting the number of solutions satisfying a Boolean formula, which is a problem instance of #SAT, has proven subtle to quantify. Even when finding individual satisfying solutions is computationally easy (e.g. 2-SAT, which is in ), determining the number of solutions can be #-hard. Recently, computational methods simulating quantum systems experienced advancements due to the development of tensor network algorithms and associated quantum physics-inspired techniques. By these methods, we give an algorithm using an axiomatic tensor contraction language for n-variable #SAT instances with complexity where c is the number of COPY-tensors, g is the number of gates, and d is the maximal degree of any COPY-tensor. Thus, n-variable counting problems can be solved efficiently when their tensor network expression has at most COPY-tensors and polynomial fan-out. This framework also admits an intuitive proof of a variant of the Tovey conjecture (the r,1-SAT instance of the Dubois-Tovey theorem). This study increases the theory, expressiveness and application of tensor based algorithmic tools and provides an alternative insight on these problems which have a long history in statistical physics and computer science.

  3. Guidelines for Improving SAT Scores.

    ERIC Educational Resources Information Center

    Thomson, Scott; DeLeonibus, Nancy

    The National Association of Secondary School Principals (NASSP) identified 34 high schools whose students maintained or improved their SAT scores from 1973 to 1976 or whose mean scores in 1973 were approximately the same as in 1965. In an open-ended questionnaire, the principals of these schools were asked to identify success factors. Their…

  4. EPR and optical absorption studies of copper ions in diglycine calcium chloride tetrahydrate

    NASA Astrophysics Data System (ADS)

    Kripal, Ram; Bajpai, Manisha

    2009-04-01

    EPR study of copper ions in diglycine calcium chloride tetrahydrate (DGCCT), [(NH 2CH 2COOH) 2·CaCl 2·4H 2O] single crystals at room temperature is carried out. The spin Hamiltonian parameters of copper ions are determined as: gx = 2.0238 ± 0.0002, gy = 2.1122 ± 0.0002, gz = 2.2250 ± 0.0002, Ax = (83 ± 2) × 10 -4 cm -1, Ay = (86 ± 2) × 10 -4 cm -1 and Az = (118 ± 2) × 10 -4 cm -1. The optical study of the single crystals at room temperature is also done and the bands are assigned to d-d and charge transfer transitions. Using above data, the nature of bonding in the complex is discussed.

  5. University NanoSat Program: AggieSat3

    DTIC Science & Technology

    2009-06-01

    for Spacecraft Testing Autonomous Rendezvous ) is important to NASA in providing flight data and experience, applicable for the Constellation Program...Nanosat 5 had two distinct stages. The first part was a design and build phase involving approximately 11 Universities, which lasted two years and...advancement toward autonomous rendezvous and docking missions. The AggieSat3 team identified the following mission objectives and was developing

  6. LifeSat - Radiation research

    NASA Technical Reports Server (NTRS)

    Nelson, Gregory A.

    1990-01-01

    Spaceflight crews will be exposed to levels of radiation which exceed those experienced on the ground. In order to reduce the uncertainty in the evaluation of risks it is necessary to validate the responses of biological systems in space under conditions which simulate exposure levels expected during exploration class missions. The LifeSat system provides the experimental capabilities to satisfy these goals. Specifically, LifeSat is capable of long duration flights of up to 60 days, is able to fly directly into trapped radiation belts and in circular or eccentric polar orbits, has the ability to provide artificial gravity and imposes fewer restrictions than the STS on the use of hazardous materials such as chemical fixatives. These features along with reference missions and experiments are discussed with respect to radiation research goals.

  7. Solitons and SeaSat,

    DTIC Science & Technology

    1984-08-01

    second statement is demonstrated to be false. The% Kadomtsev-.1etviashvile equation relevant to Internal Waves is shown not to have SOliL -solutions. This...more than one space dimension. The second statement is demonstrated to be false. The Kadomtsev-Petviashvile equation relevant to Internal Waves Is...observed by SeaSat has led to suggestions that the phenomena may be related to Internal 0 Wave Solitons. Most observations were made under conditions for

  8. DebriSat Laboratory Analyses

    DTIC Science & Technology

    2015-01-05

    foam panels. Deposits on the SEM stubs and witness plate assembly are predominantly carbon and consist of agglomerates of nano carbonaceous material...side of the support posts indicating early directional deposition from DebriSat. The coating was carbonaceous (disordered graphite) with nano metal...droplets. Fluorine from Teflon wire insulation was also common in the SEM stub and witness plates deposits. Nano droplets of metallic materials

  9. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    SciTech Connect

    Chandran, Senthilkumar; Jagan, R.; Paulraj, Rajesh; Ramasamy, P.

    2015-10-15

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm{sup −1} is assigned to the (Co–O) stretching vibrations. The optical transmission of the crystal was studied by UV–vis–NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG–DTA. The weight loss of the title compound occurs in different steps. - Graphical abstract: Molecular structure of the bis(hydrogenmaleate)-Co(II) tetrahydrate drawn at 40% ellipsoid probability level. - Highlights: • Bis(hydrogenmaleate)-Co(II) tetrahydrate single crystal is grown by slow evaporation method. • Structural and optical properties were discussed. • The title complex crystal is thermally stable up to 91 °C. • Plasma energy, Fermi energy and electronic polarizability are evaluated. • It exhibits positive photoconductivity.

  10. CryoSat-2 and the CryoSat Mission

    NASA Astrophysics Data System (ADS)

    Francis, R.; Cullen, R.

    2009-04-01

    CryoSat was chosen as the first of ESA's Earth Explorer Opportunity missions in late 1999, following a competitive selection process. Its goal is the measurement of secular change in the cryosphere, particularly in the elevation of the ice caps and the thickness of sea ice. The required accuracy corresponds to about half of the variation expected due to natural variability, over reasonable scales for the surfaces concerned. The selected technique is radar altimetry, although the instrument has been modified to provide the enhanced capabilities needed to significantly extend the spatial coverage of previous altimetry missions, particularly ERS and EnviSat. Thus the radar includes a synthetic aperture mode which enables the along- track resolution to be improved to about 250 m. This will enable detection of leads in sea-ice which are narrower than those detected hitherto, so that operation deeper into pack-ice can be achieved with a consequent reduction in errors due to omission. Altimetry over the steep edges of ice caps is hampered by the irregular topography which, since the radar ranging is performed to the closest reflector rather than the point directly below, introduces uncertainty into the exactitude of repeat measurements. CryoSat's radar includes a second antenna and receiver chain so that interferometry may be used to determine the arrival angle of the echo and so improve localisation of the reflection. The satellite payload, which includes a DORIS receiver for precise orbit determination and a set of star trackers to measure the orientation of the interferometer, is quite complex and demanding. The satellite was launched on 8 October 2005, just less than 6 years after the start of the programme. Unfortunately the launch vehicle, a Rockot launcher derived from the Russian SS-19 ICBM, suffered an anomaly at the end of its second-stage flight, with the result that the satellite was lost, the debris falling close to the North pole. Determination to rebuild

  11. SatR Is a Repressor of Fluoroquinolone Efflux Pump SatAB

    PubMed Central

    Escudero, Jose Antonio; San Millan, Alvaro; Montero, Natalia; Gutierrez, Belen; Ovejero, Cristina Martinez; Carrilero, Laura

    2013-01-01

    Streptococcus suis is an emerging zoonotic agent responsible for high-mortality outbreaks among the human population in China. In this species, the ABC transporter SatAB mediates fluoroquinolone resistance when overexpressed. Here, we describe and characterize satR, an open reading frame (ORF) encoding a MarR superfamily regulator that acts as a repressor of satAB. satR is cotranscribed with satAB, and its interruption entails the overexpression of the pump, leading to a clinically relevant increase in resistance to fluoroquinolones. PMID:23650171

  12. Thermal dehydration of magnesium acetate tetrahydrate: formation and in situ crystallization of anhydrous glass.

    PubMed

    Koga, Nobuyoshi; Suzuki, Yasumichi; Tatsuoka, Tomoyuki

    2012-12-13

    The kinetics and mechanism of the thermal dehydration of magnesium acetate tetrahydrate were investigated as a typical example of the glass formation process via the thermal decomposition of solids. Formation of an intermediate fluid phase was identified as the characteristic phenomenon responsible for the formation of anhydrous glass. Thermal dehydration from the surface fluid layer regulates the zero-order-like rate behavior of the mass-loss process with an apparent activation energy E(a) ≈ 70-80 kJ mol(-1). Because of variations in the mechanism of release of the water vapor with changes in the reaction temperature range, the mass-loss behavior is largely dependent on the particle size of the sample and heating conditions. The formation of hollow anhydrous glass is the novel finding of the present study. The mechanism of formation is discussed in terms of complementary interpretations of the morphological changes and kinetic behavior of the thermal dehydration. On further heating, the as-produced anhydrous glass exhibits a glass transition phenomenon at approximately 470 K with an E(a) ≈ 550-560 kJ mol(-1), and subsequently crystallizes via the three-dimensional growth of nuclei controlled by diffusion. The crystallization process is characterized by an E(a) ≈ 280 kJ mol(-1) and an enthalpy change ΔH = -13.3 kJ mol(-1), resulting in the formation of smaller, rounded particles of crystalline anhydrate.

  13. Solubility of triuranyl diphosphate tetrahydrate (TDT) and Na autunite at 23 and 50 degrees C

    SciTech Connect

    Armstrong, Christopher R.; Felmy, Andrew R.; Clark, Sue B.

    2010-11-01

    In this report we present experimental solubility data for well-characterized triuranyl diphosphate tetrahydrate (TDT: (UO2)(3)(PO4)(2)center dot 4H(2)O) and Na autunite (Na[UO2PO4]center dot xH(2)O) at 23 and 50 degrees C in NaClO4-HClO4 solutions at pC(H+) = 2. Duplicate samples of TDT in 0.1, 0.5, 1.0, 2.0 and 5.0 in solutions were equilibrated at 23 and 50 degrees C. TDT solid was synthesized and characterized with ICP-OES, ATR-IR and powder XRD before and after solubility experiments. The pH of the suspensions were monitored throughout the experiments. Equilibrium was achieved from undersaturation with respect to TDT and oversaturation for Na autunite. Steady-state conditions were achieved in all cases within 82 d. TDT was unstable at ionic strengths above 0.1 m, where its complete conversion to Na autunite was observed. The ion-interaction model was used to interpret the experimental solubility data. The solubility product, log K-sp, for TDT was determined to be -49.7 and -51.3 at 23 and 50 degrees C respectively. log K for Na autunite was determined to be -24.4 (23 degrees C) and -24.1 +/- 0.2 (50 degrees C).

  14. Ace the Verbal on the SAT

    ERIC Educational Resources Information Center

    Meierding, Loren

    2005-01-01

    Many students are not accepted in to certain colleges and universities because of low SAT scores. Loren Meierding has written Ace the Verbal on the SAT to help students with minimal preparation do well by improving their vocabulary and use better techniques for finding the answers to the questions. This book provides strategies needed to score…

  15. Is the SAT a 'Wealth Test'?

    ERIC Educational Resources Information Center

    Zwick, Rebecca

    2002-01-01

    Discuss whether high scores on the Scholastic Assessment Test (SAT) are associated with high student socioeconomic status, including high family income, particularly in California. Concludes that the SAT is no more a "wealth test" than is every other measure of student achievement such as grades. Describes other factors influencing…

  16. The SAT: An Essay in Uncertainty

    ERIC Educational Resources Information Center

    Mlodinow, Leonard

    2008-01-01

    In this article, the author talks about the release of the most comprehensive study of SAT exams. The headline on the Web site of the College Board, the maker of the test, was, "SAT Studies Show Test's Strength in Predicting College Success." At the same time, a headline on the Web site of the group FairTest, a 23-year-old, nonprofit…

  17. A Small Aircraft Transportation System (SATS) Demand Model

    NASA Technical Reports Server (NTRS)

    Long, Dou; Lee, David; Johnson, Jesse; Kostiuk, Peter; Yackovetsky, Robert (Technical Monitor)

    2001-01-01

    The Small Aircraft Transportation System (SATS) demand modeling is a tool that will be useful for decision-makers to analyze SATS demands in both airport and airspace. We constructed a series of models following the general top-down, modular principles in systems engineering. There are three principal models, SATS Airport Demand Model (SATS-ADM), SATS Flight Demand Model (SATS-FDM), and LMINET-SATS. SATS-ADM models SATS operations, by aircraft type, from the forecasts in fleet, configuration and performance, utilization, and traffic mixture. Given the SATS airport operations such as the ones generated by SATS-ADM, SATS-FDM constructs the SATS origin and destination (O&D) traffic flow based on the solution of the gravity model, from which it then generates SATS flights using the Monte Carlo simulation based on the departure time-of-day profile. LMINET-SATS, an extension of LMINET, models SATS demands at airspace and airport by all aircraft operations in US The models use parameters to provide the user with flexibility and ease of use to generate SATS demand for different scenarios. Several case studies are included to illustrate the use of the models, which are useful to identify the need for a new air traffic management system to cope with SATS.

  18. Test anxiety and performance-avoidance goals explain gender differences in SAT-V, SAT-M, and overall SAT scores.

    PubMed

    Hannon, Brenda

    2012-11-01

    This study uses analysis of co-variance in order to determine which cognitive/learning (working memory, knowledge integration, epistemic belief of learning) or social/personality factors (test anxiety, performance-avoidance goals) might account for gender differences in SAT-V, SAT-M, and overall SAT scores. The results revealed that none of the cognitive/learning factors accounted for gender differences in SAT performance. However, the social/personality factors of test anxiety and performance-avoidance goals each separately accounted for all of the significant gender differences in SAT-V, SAT-M, and overall SAT performance. Furthermore, when the influences of both of these factors were statistically removed simultaneously, all non-significant gender differences reduced further to become trivial by Cohen's (1988) standards. Taken as a whole, these results suggest that gender differences in SAT-V, SAT-M, and overall SAT performance are a consequence of social/learning factors.

  19. Periodically Launched, Dedicated CubeSats/SmallSats for Space Situational Awareness Through NASA Communications Networks

    NASA Astrophysics Data System (ADS)

    Stromberg, E. M.; Shaw, H.; Estabrook, P.; Neilsen, T. L.; Gunther, J.; Swenson, C.; Fish, C. S.; Schaire, S. H.

    2014-12-01

    Space Situational Awareness (SSA) is an area where spaceflight activities and missions can directly influence the quality of life on earth. The combination of space weather, near earth orbiting objects, atmospheric conditions at the space boundary, and other phenomena can have significant short-term and long-term implications for the inhabitants of this planet. The importance of SSA has led to increased activity in this area from both space and ground based platforms. The emerging capability of CubeSats and SmallSats provides an opportunity for these low-cost, versatile platforms to augment the SSA infrastructure. The CubeSats and SmallSats can be launched opportunistically with shorter lead times than larger missions. They can be organized both as constellations or individual sensor elements. Combining CubeSats and SmallSats with the existing NASA communications networks (TDRS Space Network, Deep Space Network and the Near Earth Network) provide a backbone structure for SSA which can be tied to a SSA portal for data distribution and management. In this poster we will describe the instruments and sensors needed for CubeSat and SmallSat SSA missions. We will describe the architecture and concept of operations for a set of opportunistic, periodically launched, SSA CubeSats and SmallSats. We will also describe the integrated communications infrastructure to support end-to-end data delivery and management to a SSA portal.

  20. Properties of the Sodium Naproxen-Lactose-Tetrahydrate Co-Crystal upon Processing and Storage.

    PubMed

    Sovago, Ioana; Wang, Wenbo; Qiu, Danwen; Raijada, Dhara; Rantanen, Jukka; Grohganz, Holger; Rades, Thomas; Bond, Andrew D; Löbmann, Korbinian

    2016-04-19

    Co-crystals and co-amorphous systems are two strategies to improve the physical properties of an active pharmaceutical ingredient and, thus, have recently gained considerable interest both in academia and the pharmaceutical industry. In this study, the behavior of the recently identified sodium naproxen-lactose-tetrahydrate co-crystal and the co-amorphous mixture of sodium, naproxen, and lactose was investigated. The structure of the co-crystal is described using single-crystal X-ray diffraction. The structural analysis revealed a monoclinic lattice, space group P21, with the asymmetric unit containing one molecule of lactose, one of naproxen, sodium, and four water molecules. Upon heating, it was observed that the co-crystal transforms into a co-amorphous system due to the loss of its crystalline bound water. Dehydration and co-amorphization were studied using synchrotron X-ray radiation and thermogravimetric analysis (TGA). Subsequently, different processing techniques (ball milling, spray drying, and dehydration) were used to prepare the co-amorphous mixture of sodium, naproxen, and lactose. X-ray powder diffraction (XRPD) revealed the amorphous nature of the mixtures after preparation. Differential scanning calorimetry (DSC) analysis showed that the blends were single-phase co-amorphous systems as indicated by a single glass transition temperature. The samples were subsequently tested for physical stability under dry (silica gel at 25 and 40 °C) and humid conditions (25 °C/75% RH). The co-amorphous samples stored at 25 °C/75% RH quickly recrystallized into the co-crystalline state. On the other hand, the samples stored under dry conditions remained physically stable after five months of storage, except the ball milled sample stored at 40 °C which showed signs of recrystallization. Under these dry conditions, however, the ball-milled co-amorphous blend crystallized into the individual crystalline components.

  1. [A Low-temperature Manganese Chloride Tetrahydrate Improves the Image Quality of Magnetic Resonance Cholangiopancreatography].

    PubMed

    Watanabe, Kunihiro; Ishimori, Yoshiyuki; Sakurai, Hitoshi; Iwai, Yuji; Miida, Kazuo; Kurita, Kouki

    2016-04-01

    Manganese chloride tetrahydrate (MCT) is one of the oral negative contrast agents which is indispensable for imaging of magnetic resonance cholangiopancreatography (MRCP). In this study, improvement of the image quality of MRCP by using low-temperature MCT is verified. All MR imagings were performed using 1.5 T scanner. The T(1) and T(2) values of the different temperature MCTs were measured in the phantom study. Different concentrations of MCT-doped water (30%, 50%, 70%, and 90%) were measured at several temperature conditions (10°C, 15°C, 23°C, 35°C, and 40°C). As a result, the T(1) and T(2) values became larger with a temperature rise. It was more remarkable in low-concentration MCT. Then, 17 healthy subjects were scanned two times with different temperatures of MCT. The MCT of the normal temperature (23°C) and low temperature (10°C) were taken at consecutive 2 days. The contrast between the stomach and the spleen were significantly higher in 2D half Fourier acquisition single shot turbo spin echo (HASTE) images by use of the low-temperature MCT. The contrast between the common bile duct and the adjacent background were significantly higher in the source images of 3D MRCP by use of the low temperature MCT. In addition, 76% of subjects answered in the questionnaire that the low temperature MCT is easier to drink. The low temperature MCT improves the image quality of MRCP and contributes to performing noninvasive examination.

  2. PhoneSat - The Smartphone Nanosatellite

    NASA Technical Reports Server (NTRS)

    Cockrell, James J.; Yost, Bruce; Petro, Andrew

    2013-01-01

    NASAs PhoneSat project will test whether spacecraft can be built using smartphones to launch the lowest-cost satellites ever flown in space. Each PhoneSat nanosatellite is one cubesat unit - a satellite in a 10 cm (approx. 4 inches) cube or about the size of a tissue box - and weighs approximately three pounds. Engineers believe PhoneSat technology will enable NASA to launch multiple new satellites capable of conducting science and exploration missions at a small fraction of the cost of conventional satellites.

  3. PhoneSat - The Smartphone Nanosatellite

    NASA Technical Reports Server (NTRS)

    Cockrell, James J.; Yost, Bruce; Petro, Andrew

    2013-01-01

    NASA's PhoneSat project tests whether spacecraft can be built using smartphones to launch the lowest-cost satellites ever flown in space. Each PhoneSat nanosatellite is one cubesat unit - a satellite in a 10 cm (approx. 4 inches) cube or about the size of a tissue box - and weighs approximately 1 kg (2.2 pounds). Engineers believe PhoneSat technology will enable NASA to launch multiple new satellites capable of conducting science and exploration missions at a small fraction of the cost of conventional satellites.

  4. SAT-Solving Based on Boundary Point Elimination

    NASA Astrophysics Data System (ADS)

    Goldberg, Eugene; Manolios, Panagiotis

    We study the problem of building structure-aware SAT-solvers based on resolution. In this study, we use the idea of treating a resolution proof as a process of Boundary Point Elimination (BPE). We identify two problems of using SAT-algorithms with Conflict Driven Clause Learning (CDCL) for structure-aware SAT-solving. We introduce a template of resolution based SAT-solvers called BPE-SAT that is based on a few generic implications of the BPE concept. BPE-SAT can be viewed as a generalization of CDCL SAT-solvers and is meant for building new structure-aware SAT-algorithms. We give experimental results substantiating the ideas of the BPE approach. In particular, to show the importance of structural information we compare an implementation of BPE-SAT and state-of-the-art SAT-solvers on narrow CNF formulas.

  5. HaloSat- A CubeSat to Study the Hot Galactic Halo

    NASA Astrophysics Data System (ADS)

    Kaaret, Philip

    We propose to develop, build, and fly HaloSat, a CubeSat capable of measuring the oxygen line emission from the hot Galactic halo. A dedicated CubeSat enables an instrument design and observing strategy to maximize the halo signal while minimizing foregrounds from solar wind charge exchange interactions within the solar system. We will use HaloSat to map the distribution of hot gas in the Milky Way and determine whether it fills an extended, and thus massive halo, or whether the halo is compact, and thus does not contribute significantly to the total mass of the Milky Way. HaloSat can be accomplished at modest cost using a CubeSat, a novel platform for space astrophysics missions. We will use a commercially available CubeSat bus and commercially available X-ray detectors to reduce development risk and minimize overall mission cost. HaloSat builds on the initiatives of GSFC/Wallops Flight Facility (WFF) in the development of CubeSats for low cost access to space and relies on the technical expertise of WFF personnel for spacecraft and mission design and operations. The team, from University of Iowa (UI), GSFC, Johns Hopkins, and CNRS (France), contains experts in X-ray detector development and data analysis and the astrophysics of hot plasmas and Galactic structure. The UI team will include a number of junior researchers (undergraduates, graduate students, and a postdoc) and help train them for future leadership roles on NASA space flight missions.

  6. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    NASA Astrophysics Data System (ADS)

    Chandran, Senthilkumar; Jagan, R.; Paulraj, Rajesh; Ramasamy, P.

    2015-10-01

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm-1 is assigned to the (Co-O) stretching vibrations. The optical transmission of the crystal was studied by UV-vis-NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG-DTA. The weight loss of the title compound occurs in different steps.

  7. CloudSat View of Flossie

    NASA Video Gallery

    CloudSat passed directly over Tropical Storm Flossie on July 29 and showed cumulus and stratocumulus clouds in northern Hawaii and cumulonimbus clouds over the southern part. Large amounts of liqui...

  8. Score Trends, SAT Validity and Subgroup Differences

    ERIC Educational Resources Information Center

    Camara, Wayne

    2008-01-01

    Presented at the Summer Institute on College Admissions at Harvard in June 2008. The presentation explores whether the SAT validity has changed with the test changes and if those changes affect specific subgroups.

  9. Answering when opportunity knocks - SATS goes global.

    PubMed

    Bateman, Chris

    2012-02-23

    One local doctor, by grasping random overlapping educational opportunities, has become the catalyst for 'Doctors without Borders' (MSF) wanting to adopt the South African Triage Scale (SATS) as its standard emergency protocol for resource-poor countries world-wide.

  10. PhoneSat - The Smartphone Nanosatellite

    NASA Technical Reports Server (NTRS)

    Westley, Deborah; Yost, Bruce; Petro, Andrew

    2013-01-01

    PhoneSat 2.4, carried into space on November 19, 2013 aboard a Minotaur I rocket from the Mid-Atlantic Regional Spaceport at NASAs Wallops Flight Facility in Virginia, is the first of the PhoneSat family to use a two-way S-band radio to allow engineers to command the satellite from Earth. This mission also serves as a technology demonstration for a novel attitude determination and control system (ADCS) that establishes and stabilizes the satellites attitude relative to Earth. Unlike the earlier PhoneSats that used a Nexus One, PhoneSat 2.4 uses the Nexus S smartphone, which runs Googles Android operating system, and is made by Samsung Electronics Co., Suwon, So. Korea. The smartphone provides many of the functions needed by the satellite such as a central computer, data memory, ready-made interfaces for communications, navigation and power all pre-assembled in a rugged electronics package.

  11. Joint SatOPS Compatibility Efforts

    NASA Technical Reports Server (NTRS)

    Smith, Danford

    2010-01-01

    This slide presentation reviews NASA Goddard Space Flight Center's (GSFC) participation in the interagency cooperation committee, the Joint SatOps Compatibility Committee (JSCC), and the compatible Sat 2 efforts. Part of GSFC's participation in the JSCC is to work with the Goddard Mission Systems Evolution Center (GMSEC) to provides a publish/subscribe framework to enable rapid integration of commercially available satellite control products.

  12. The NASA CloudSat Education Network

    NASA Astrophysics Data System (ADS)

    Krumm, D. K.

    2006-05-01

    CloudSat, a NASA Earth System Science Pathfinder Mission, will launch into orbit the world's most advanced weather radar designed to measure properties of clouds that are essential for accurate understanding of Earth's weather and climate processes. Providing the first vertical profiles of global measurements of cloud thickness, height, water and ice content and a wide range of precipitation data linked to cloud development, CloudSat measurements will fill a critical gap in understanding how clouds affect climate. Any mission of this nature requires extensive ground-based reference data. The CloudSat Education Network provides the opportunity for schools around the world to partner with the CloudSat Science Team and the NASA-sponsored GLOBE Program. The Network will link together scientists, students, teachers, and their communities to give students meaningful, authentic and contemporary science education experiences. Student activities and learning outcomes are being developed to meet both general education outcomes and specific standards or objectives from school curricula. The main focus of the knowledge development component of the project is to help students better understand long-term climate change and the climatic processes that maintain the Earth's Energy balance. Student research with CloudSat/GLOBE data will be strongly encouraged. Scientists will receive research-quality data in support of the mission and in return will interact with teachers and their students to promote interest in science. Participation in the network throughout the duration of the project will be monitored and schools will be asked to maintain levels of participation in order to give CloudSat scientists a solid consistent base of data to support their research. The preferred base level of participation is the reporting of cloud, temperature and precipitation data according to modified GLOBE protocols approximately every 16 days coinciding with the CloudSat satellite overpass. The

  13. KidSat: Image User's Manual

    NASA Technical Reports Server (NTRS)

    Way, JoBea; Andres, Paul; Baker, John; Goodson, Greg; Marshall, William; McGuire, John; Rackley, Kathleen; Stork, Elizabeth Jones; Yiu, Lisa

    1999-01-01

    The goal of KidSat was to provide young students with the opportunity to participate directly in the NASA space program and to enhance learning in the process. The KidSat pilot project was focused on using a color digital camera, mounted on the space shuttle, to take pictures of the Earth. These could be used to enhance middle school curricula. The project not only benefited middle school students, who were essentially the Science Team, responsible for deciding where to take pictures, but it also benefited high school students and undergraduates, who were essentially the Project Team, responsible for the development and implementation of the project. KidSat flew on three missions as part of the pilot project: STS-76, STS-81, and STS-86. This document describes the goals, project elements, results, and data for the three KidSat missions that made up the pilot program. It serves as a record for this pilot project and may be used as a reference for similar projects. It can also be a too] in using the data to its fullest extent. The KidSat Web page remains on-line at http://kidsat.jpl.nasa.gov/kidsat, and the images may be downloaded in their full resolution.

  14. CryoSat Quality Control- Sensitivity Study of CryoSat Variables

    NASA Astrophysics Data System (ADS)

    Hall, Amanda; Mannan, Rubinder; Webb, Erica; Bouffard, Jerome; Femenias, Pierre; Cipollini, Paolo; Calafat, Francisco

    2016-08-01

    Parameters and geophysical corrections provided in L1, L2I and L2 CryoSat Ice products are currently checked using the Quality Control for CryoSat (QCC) tool integrated at PDGS. This tool provides configurable quality control for CryoSat data products according to a predefined Test Definition File (TDF). A detailed analysis has recently been performed to tune these thresholds, as the current thresholds were defined at the start of the CryoSat mission. The study was extended to the recently released CryoSat Ocean Products: IOP and GOP. The updated test thresholds have now been approved and the new version of the QCC tool will be implemented to operationally screen all CryoSat Baseline-C Ice and Ocean products. This paper presents the threshold updates resulting from this analysis, a summary of statistical results and an overview of the trends of two CryoSat variables, including plots of temporal changes in operational Baseline-C data.

  15. TemperSAT: A new efficient fair-sampling random k-SAT solver

    NASA Astrophysics Data System (ADS)

    Fang, Chao; Zhu, Zheng; Katzgraber, Helmut G.

    The set membership problem is of great importance to many applications and, in particular, database searches for target groups. Recently, an approach to speed up set membership searches based on the NP-hard constraint-satisfaction problem (random k-SAT) has been developed. However, the bottleneck of the approach lies in finding the solution to a large SAT formula efficiently and, in particular, a large number of independent solutions is needed to reduce the probability of false positives. Unfortunately, traditional random k-SAT solvers such as WalkSAT are biased when seeking solutions to the Boolean formulas. By porting parallel tempering Monte Carlo to the sampling of binary optimization problems, we introduce a new algorithm (TemperSAT) whose performance is comparable to current state-of-the-art SAT solvers for large k with the added benefit that theoretically it can find many independent solutions quickly. We illustrate our results by comparing to the currently fastest implementation of WalkSAT, WalkSATlm.

  16. O/OREOS Sat: Organism/Organic Exposure to Orbital Stresses

    NASA Astrophysics Data System (ADS)

    Ehrenfreund, Pascale; Quinn, R.; Mattioda, A.; Bramall, N.; Bryson, K.; Chittenden, J.; Ricco, A.; Squires, D.; Santos, O.; Minelli, G.; Defouw, G.; Friedericks, C.; Landis, D.

    O/OREOS Sat is the first triple-cubesat mission of the NASA Astrobiology Small Payloads pro-gram. O/OREOS Sat will reach an orbit of 680 km and operate for at least 6 months. Success criteria for this mission are to (1) demonstrate the opportunities available for small satellites in astrobiology/chemical science research programs, (2) measure the degradation of(bio)organic molecules in a variety of astrobiologically relevant space environments, (3) demonstrate the capability to simulate a variety of space environments using small satellites, and (4) develop a robust and capable new small-sat in-situ measurement technology: UV-visible spectroscopy us-ing the Sun as light source. O/OREOS Sat investigates the stability of organic material in space by exposing four classes of organic molecules to the space environment: amino acid, quinone, polycyclic aromatic hydrocarbon, and metallo-porphyrin. One of each specimen will be main-tained in four self-contained micro-environments. The main objectives are to use changes in UV and visible absorption spectra to quantitatively measure the effects upon organic specimens of the combined exposure to space radiation and UV and visible light while in relevant space environments. O/OREOS Sat is scheduled to launch in May 2010 from Kodiak, Alaska on a Minotaur IV rocket and we report on the first results on O/OREOS in orbit.

  17. Partitioning SAT Instances for Distributed Solving

    NASA Astrophysics Data System (ADS)

    Hyvärinen, Antti E. J.; Junttila, Tommi; Niemelä, Ilkka

    In this paper we study the problem of solving hard propositional satisfiability problem (SAT) instances in a computing grid or cloud, where run times and communication between parallel running computations are limited.We study analytically an approach where the instance is partitioned iteratively into a tree of subproblems and each node in the tree is solved in parallel.We present new methods for constructing partitions which combine clause learning and lookahead. The methods are incorporated into the iterative approach and its performance is demonstrated with an extensive comparison against the best sequential solvers in the SAT competition 2009 as well as against two efficient parallel solvers.

  18. SAT Participation and Performance for the Class of 2014. Memorandum

    ERIC Educational Resources Information Center

    Sanderson, Geoffrey T.

    2014-01-01

    SAT participation and performance are milestones on the path to college and career readiness. This report provides the results for SAT participation and performance in Montgomery County (Maryland) Public Schools (MCPS) for the class of 2014. Analysis of postsecondary outcomes for MCPS graduates indicates that graduates who took the SAT were more…

  19. Issues of Validity of SAT Subject Test: Korean with Listening

    ERIC Educational Resources Information Center

    Lee, Saekyun H.; Han, Hyunjoo

    2007-01-01

    This study investigated some issues regarding the validity of the Scholastic Achievement Test (SAT) Subject Test: Korean with Listening. The SAT Korean has been administered just once a year since its inception in 1997. As of March 2006, it had been administered nine times. However, SAT foreign language tests are not as rigorously researched as…

  20. Two CubeSats Deployed from the International Space Station

    NASA Video Gallery

    This movie of a CubeSat deployment from the International Space Station shows a compilation of photos taken by astronauts on May 16, 2016. The bottom-most CubeSat is the NASA-funded MinXSS CubeSat,...

  1. Overestimation Bias in Self-Reported SAT Scores

    ERIC Educational Resources Information Center

    Mayer, Richard E.; Stull, Andrew T.; Campbell, Julie; Almeroth, Kevin; Bimber, Bruce; Chun, Dorothy; Knight, Allan

    2007-01-01

    The authors analyzed self-reported SAT scores and actual SAT scores for five different samples of college students (N = 650). Students overestimated their actual SAT scores by an average of 25 points (SD = 81, d = 0.31), with 10% under-reporting, 51% reporting accurately, and 39% over-reporting, indicating a systematic bias towards over-reporting.…

  2. Analysis of the WindSat Receiver Frequency Passbands

    DTIC Science & Technology

    2014-09-12

    Unclassified Unlimited 17 Michael H. Bettenhausen (202) 767-8278 The WindSat instrument is the primary payload for the Coriolis mission which was launched...INTRODUCTION The WindSat instrument is the primary payload for the Coriolis mission which was launched on 6 Jan- uary 2003. WindSat is a 22-channel

  3. HaloSat - A CubeSat to Study the Hot Galactic Halo

    NASA Astrophysics Data System (ADS)

    Kaaret, Philip

    2016-04-01

    Observations of the nearby universe fail to locate about half of the normal matter (baryons) observed in the early universe. The missing baryons may be in hot galactic halos. HaloSat is a CubeSat designed to map oxygen line emission (O VII and O VIII) around the Milky Way in order to constrain the mass and spatial distribution of hot gas in the halo. HaloSat has a grasp competitive with current X-ray observatories. Its observing program will be optimized to minimize contributions from solar wind charge exchange (SWCX) emission that limit the accuracy of current measurements. We will describe the HaloSat mission concept, progress towards its implementation, and plans for archiving and distribution of the data.

  4. HaloSat - A CubeSat to Study the Hot Galactic Halo

    NASA Astrophysics Data System (ADS)

    Kaaret, Philip

    2017-01-01

    Observations of the nearby universe fail to locate about half of the baryons observed in the early universe. The missing baryons may be in hot galactic halos. HaloSat is a CubeSat designed to map oxygen line emission (O VII and O VIII) around the Milky Way in order to constrain the mass and spatial distribution of hot gas in the halo. HaloSat has a grasp competitive with current X-ray observatories. Its observing program will be optimized to minimize contributions from solar wind charge exchange (SWCX) emission that limit the accuracy of current measurements. We will describe the HaloSat mission concept, progress towards its implementation, and plans for archiving and distribution of the data.

  5. Pre- to Post- CubeSats

    NASA Astrophysics Data System (ADS)

    Cutler, J.

    2015-12-01

    CubeSats sprung from a formative picosatellite effort at a university in the heart of Silicon Valley, took root in a university-led university environment, and have grown into complex-shaped explorers in both near and soon-to-be deep space. Private citizens, businesses, government are building and launching a variety of science, technology demonstration, and service missions. A new generation of space explorers is gaining first hand experience in space missions at all educational levels. There is new life and new energy in the space program. However, space is still difficult. The environment is harsh. Funding is sparse. This talk explores this history and the future of CubeSats from the context of a university-centric laboratory that emphasizes teaching, research, and entrepreneurial impact. It will explore the following questions: What sparked the CubeSat innovation? What are longer lasting lessons of this community? Where are places we can go next? What does it take to get there? The talk will draw on lessons learned from building over six on-orbit CubeSat missions and training hundreds of space engineers.

  6. Investigating SATS-36 for a Matriculation Sample

    ERIC Educational Resources Information Center

    Krishnan, Saras; Idris, Noraini

    2015-01-01

    Students' attitudes towards statistics have been more often negative due to many factors such as initial perception of the subject, low ability in mathematics and lack of motivation to study statistics. Studies involving SATS-36 included investigation of the different factors in relation to students' attitude towards statistics. Other studies have…

  7. SAT Scores at NAIS Member Schools

    ERIC Educational Resources Information Center

    Torres, Amada

    2015-01-01

    Between March and June 2014, more than 1.67 million students from the 2014 graduating class took the SAT, marking a new participation record for the test. At the request of the National Association of Independent Schools (NAIS), the College Board created a special report that allows the association to compare how independent school students fared…

  8. Unflagged SATs: Who Benefits from Special Accommodations?

    ERIC Educational Resources Information Center

    Abrams, Samuel J.

    2005-01-01

    When the College Board announced, in the summer of 2002, that it would stop "flagging" the test scores of students who were given special accommodations for the SAT, the gold standard exam for college admission, disability advocates were thrilled. "A triumphant day for millions of people with dyslexia and other disabilities,"…

  9. The RadioSat (sm) network

    NASA Technical Reports Server (NTRS)

    Noreen, Gary K.

    1991-01-01

    The RadioSat network under development by radio Satellite Corporation will use mobile satellite (MSAT) technology to provide diverse personal communications, broadcast, and navigation services. The network will support these services simultaneously for integrated mobile radios throughout Canada and the United States. The RadioSat network takes advantage of several technological breakthroughs, all coming to fruition by the time the first MSAT satellite is launched in 1994. The most important of these breakthroughs is the enormous radiated power of each MSAT spacecraft - orders of magnitude greater than the radiated power of previous L-band spacecraft. Another important breakthrough is the development of advanced digital audio compression algorithms, enabling the transmission of broadcast quality music at moderate data rates. Finally, continuing dramatic increases in VLSI capabilities permit the production of complex, multi-function mobile satellite radios in very large quantities at prices little more than those of conventional car radios. In addition to performance breakthroughs and their economic implications to RadioSat, the design of the RadioSat network is reviewed.

  10. SAT Scores, Journalism and Public Policy.

    ERIC Educational Resources Information Center

    Meyer, Philip

    1993-01-01

    The two symposium articles extend "USA Today" SAT state ranking efforts by examining which states have the highest achievers, add the most value to enrolled students, and use resources most effectively. Dynarski and Gleason show that this test measures educational achievement more than innate ability. Graham and Husted adjust rankings…

  11. CubeSat evolution: Analyzing CubeSat capabilities for conducting science missions

    NASA Astrophysics Data System (ADS)

    Poghosyan, Armen; Golkar, Alessandro

    2017-01-01

    Traditionally, the space industry produced large and sophisticated spacecraft handcrafted by large teams of engineers and budgets within the reach of only a few large government-backed institutions. However, over the last decade, the space industry experienced an increased interest towards smaller missions and recent advances in commercial-off-the-shelf (COTS) technology miniaturization spurred the development of small spacecraft missions based on the CubeSat standard. CubeSats were initially envisioned primarily as educational tools or low cost technology demonstration platforms that could be developed and launched within one or two years. Recently, however, more advanced CubeSat missions have been developed and proposed, indicating that CubeSats clearly started to transition from being solely educational and technology demonstration platforms to offer opportunities for low-cost real science missions with potential high value in terms of science return and commercial revenue. Despite the significant progress made in CubeSat research and development over the last decade, some fundamental questions still habitually arise about the CubeSat capabilities, limitations, and ultimately about their scientific and commercial value. The main objective of this review is to evaluate the state of the art CubeSat capabilities with a special focus on advanced scientific missions and a goal of assessing the potential of CubeSat platforms as capable spacecraft. A total of over 1200 launched and proposed missions have been analyzed from various sources including peer-reviewed journal publications, conference proceedings, mission webpages as well as other publicly available satellite databases and about 130 relatively high performance missions were downselected and categorized into six groups based on the primary mission objectives including "Earth Science and Spaceborne Applications", "Deep Space Exploration", "Heliophysics: Space Weather", "Astrophysics", "Spaceborne In Situ

  12. Achievements and Future Plan of Interplanetary CubeSats and Micro-Sats in Japan

    NASA Astrophysics Data System (ADS)

    Funase, Ryu

    2016-07-01

    This paper introduces Japanese achievements and future plans of CubeSats and Micro-Sats for deep space exploration. As the first step toward deep space mission by such tiny spacecraft, University of Tokyo and Japan Aerospace Exploration Agency (JAXA) developed the world's first deep space micro-spacecraft PROCYON (Proximate Object Close flYby with Optical Navigation). Its mission objective is to demonstrate a micro-spacecraft bus technology for deep space exploration and proximity flyby to asteroids performing optical measurements. PROCYON was launched into the Earth departure trajectory on December 3, 2014 together with Japanese asteroid sample return mission Hayabusa-2. PROCYON successfully completed the bus system demonstration mission in its interplanetary flight. Currently, Japan is not only pursuing the improvement and utilization of the demonstrated micro-sat deep space bus system with a weight of tens of kg or more for more practical scientific deep space missions, but also trying to develop smaller spacecraft with a weight of less than tens of kg, namely CubeSats, for deep space exploration. We are proposing a self-contained 6U CubeSat mission for the rideshare opportunity on the USA's SLS EM-1 mission, which will fly to a libration orbit around Earth-Moon L2 point and perform scientific observations of the Earth and the Moon. We are also seeking the possibility of CubeSats which is carried by a larger spacecraft to the destination and supports the mission by taking advantage of its low-cost and risk-tolerable feature. As an example of such style of CubeSat missions, we are studying a CubeSat for close observations of an asteroid, which will be carried to the target asteroid by a larger mother spacecraft. This CubeSat is released from the mother spacecraft to make a close flyby for scientific observations, which is difficult to be performed by the mother spacecraft if we consider the risk of the collision to the target asteroid or dust particles ejected

  13. COLD-SAT feasibility study safety analysis

    NASA Technical Reports Server (NTRS)

    Mchenry, Steven T.; Yost, James M.

    1991-01-01

    The Cryogenic On-orbit Liquid Depot-Storage, Acquisition, and Transfer (COLD-SAT) satellite presents some unique safety issues. The feasibility study conducted at NASA-Lewis desired a systems safety program that would be involved from the initial design in order to eliminate and/or control the inherent hazards. Because of this, a hazards analysis method was needed that: (1) identified issues that needed to be addressed for a feasibility assessment; and (2) identified all potential hazards that would need to be controlled and/or eliminated during the detailed design phases. The developed analysis method is presented as well as the results generated for the COLD-SAT system.

  14. LifeSat - A new research vehicle

    NASA Technical Reports Server (NTRS)

    Gilbreath, William P.; Dunning, Robert W.

    1990-01-01

    LifeSat is a reusable recoverable satellite that will support research in the gravitation and radiation biology fields. It can provide sustained lower gravitational levels than manned vehicles and can access orbits where specimens can be exposed to cosmic radiation. The satellite design encompasses environmental support for vertebrate, invertebrate and plant specimens ranging from cells and tissues up to small mammals. The first launch, in a series of 7 satellite flights, is planned for late 1995.

  15. ExoplanetSat: detecting transiting exoplanets using a low-cost CubeSat platform

    NASA Astrophysics Data System (ADS)

    Smith, Matthew W.; Seager, Sara; Pong, Christopher M.; Villaseñor, Jesus S.; Ricker, George R.; Miller, David W.; Knapp, Mary E.; Farmer, Grant T.; Jensen-Clem, Rebecca

    2010-07-01

    Nanosatellites, i.e. spacecraft that weigh between 1 and 10 kg, are drawing increasing interest as platforms for conducting on-orbit science. This trend is primarily driven by the ability to piggyback nanosatellites on the launch of large spacecraft and hence achieve orbit at greatly reduced cost. The CubeSat platform is a standardized nanosatellite configuration, consisting of one, two, or three 10 cm x 10 cm x 10 cm units (1, 2, or 3 "U"s) arranged in a row. We present a CubeSat-based concept for the discovery of transiting exoplanets around the nearest and brightest Sun-like stars. The spacecraft prototype - termed ExoplanetSat - is a 3U space telescope capable of monitoring a single target star from low Earth orbit. Given the volume limitations of the CubeSat form factor, designing a capable spacecraft requires overcoming significant challenges. This work presents the initial satellite configuration along with several subsystem-specific solutions to the aforementioned constraints. An optical design based on a modified commercial off-the-shelf camera lens is given. We also describe a novel two-stage attitude control architecture that combines 3-axis reaction wheels for coarse pointing with a piezoelectric translation stage at the focal plane for fine pointing. Modeling and simulation results are used to demonstrate feasibility by quantifying ExoplanetSat pointing precision, signal-to-noise ratio, guide star magnitude, and additional design parameters which determine system performance.

  16. Big Software for SmallSats: Adapting CFS to CubeSat Missions

    NASA Technical Reports Server (NTRS)

    Cudmore, Alan P.; Crum, Gary; Sheikh, Salman; Marshall, James

    2015-01-01

    Expanding capabilities and mission objectives for SmallSats and CubeSats is driving the need for reliable, reusable, and robust flight software. While missions are becoming more complicated and the scientific goals more ambitious, the level of acceptable risk has decreased. Design challenges are further compounded by budget and schedule constraints that have not kept pace. NASA's Core Flight Software System (cFS) is an open source solution which enables teams to build flagship satellite level flight software within a CubeSat schedule and budget. NASA originally developed cFS to reduce mission and schedule risk for flagship satellite missions by increasing code reuse and reliability. The Lunar Reconnaissance Orbiter, which launched in 2009, was the first of a growing list of Class B rated missions to use cFS. Large parts of cFS are now open source, which has spurred adoption outside of NASA. This paper reports on the experiences of two teams using cFS for current CubeSat missions. The performance overheads of cFS are quantified, and the reusability of code between missions is discussed. The analysis shows that cFS is well suited to use on CubeSats and demonstrates the portability and modularity of cFS code.

  17. Big Software for SmallSats: Adapting cFS to CubeSat Missions

    NASA Technical Reports Server (NTRS)

    Cudmore, Alan P.; Crum, Gary Alex; Sheikh, Salman; Marshall, James

    2015-01-01

    Expanding capabilities and mission objectives for SmallSats and CubeSats is driving the need for reliable, reusable, and robust flight software. While missions are becoming more complicated and the scientific goals more ambitious, the level of acceptable risk has decreased. Design challenges are further compounded by budget and schedule constraints that have not kept pace. NASA's Core Flight Software System (cFS) is an open source solution which enables teams to build flagship satellite level flight software within a CubeSat schedule and budget. NASA originally developed cFS to reduce mission and schedule risk for flagship satellite missions by increasing code reuse and reliability. The Lunar Reconnaissance Orbiter, which launched in 2009, was the first of a growing list of Class B rated missions to use cFS.

  18. Advances in Ka-Band Communication System for CubeSats and SmallSats

    NASA Technical Reports Server (NTRS)

    Kegege, Obadiah; Wong, Yen F.; Altunc, Serhat

    2016-01-01

    A study was performed that evaluated the feasibility of Ka-band communication system to provide CubeSat/SmallSat high rate science data downlink with ground antennas ranging from the small portable 1.2m/2.4m to apertures 5.4M, 7.3M, 11M, and 18M, for Low Earth Orbit (LEO) to Lunar CubeSat missions. This study included link analysis to determine the data rate requirement, based on the current TRL of Ka-band flight hardware and ground support infrastructure. Recent advances in Ka-band transceivers and antennas, options of portable ground stations, and various coverage distances were included in the analysis. The link/coverage analysis results show that Cubesat/Smallsat missions communication requirements including frequencies and data rates can be met by utilizing Near Earth Network (NEN) Ka-band support with 2 W and high gain (>6 dBi) antennas.

  19. TechEdSat Nano-Satellite Series Fact Sheet

    NASA Technical Reports Server (NTRS)

    Murbach, Marcus; Martinez, Andres; Guarneros Luna, Ali

    2014-01-01

    TechEdSat-3p is the second generation in the TechEdSat-X series. The TechEdSat Series uses the CubeSat standards established by the California Polytechnic State University Cal Poly), San Luis Obispo. With typical blocks being constructed from 1-unit (1U 10x10x10 cm) increments, the TechEdSat-3p has a 3U volume with a 30 cm length. The project uniquely pairs advanced university students with NASA researchers in a rapid design-to-flight experience lasting 1-2 semesters.The TechEdSat Nano-Satellite Series provides a rapid platform for testing technologies for future NASA Earth and planetary missions, as well as providing students with an early exposure to flight hardware development and management.

  20. Finite-Size Scaling in Random K-SAT Problems

    NASA Astrophysics Data System (ADS)

    Ha, Meesoon; Lee, Sang Hoon; Jeon, Chanil; Jeong, Hawoong

    2010-03-01

    We propose a comprehensive view of threshold behaviors in random K-satisfiability (K-SAT) problems, in the context of the finite-size scaling (FSS) concept of nonequilibrium absorbing phase transitions using the average SAT (ASAT) algorithm. In particular, we focus on the value of the FSS exponent to characterize the SAT/UNSAT phase transition, which is still debatable. We also discuss the role of the noise (temperature-like) parameter in stochastic local heuristic search algorithms.

  1. Soil aquifer treatment (SAT) system: a case study.

    PubMed

    Kaur, Samanpreet; Singh, Mandeep

    2002-07-01

    Water scarcity is the major issue in all parts of world. Wastewater reuse is one alternative. SAT proves to efficient, economical and feasible method for wastewater treatment. SAT system achieves an excellent reduction of biochemical oxygen demand, suspended solids, and fecal coliform. About 90% of water applied to SAT site is returned to watershed. A case study has been made by the authors to increase the efficiency of this system.

  2. Development of Novel Integrated Antennas for CubeSats

    NASA Technical Reports Server (NTRS)

    Jackson, David; Fink, Patrick W.; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Development of Novel Integrated Antennas for CubeSats project is directed at the development of novel antennas for CubeSats to replace the bulky and obtrusive antennas (e.g., whip antennas) that are typically used. The integrated antennas will not require mechanical deployment and thus will allow future CubeSats to avoid potential mechanical problems and therefore improve mission reliability. Furthermore, the integrated antennas will have improved functionality and performance, such as circular polarization for improved link performance, compared with the conventional antennas currently used on CubeSats.

  3. MarsSat: assured communication with Mars.

    PubMed

    Gangale, Thomas

    2005-12-01

    The author developed the MarsSat concept during the 1990s. For this task, he designed a class of orbits to solve the problem of communicating with crews on Mars when the planet is in solar conjunction as seen from Earth, a planetary configuration that occurs near the midpoint of a conjunction class mission to Mars. This type of orbit minimizes the distance between Mars and the communications satellite; thus, minimizing the size, weight, and power requirements, while providing a simultaneous line-of-sight to both Earth and Mars. The MarsSat orbits are solar orbits that have the same period as Mars, but are inclined a few degrees out of the plane of the Mars orbit and also differ in eccentricity from the orbit of Mars. These differences cause a spacecraft in this orbit to rise North of Mars, then fall behind Mars, then drop South of Mars, and then pull ahead of Mars, by some desired distance in each case-typically about 20 million kilometers-in order to maintain an angular separation of a couple of degrees as seen from a point in the orbit of Earth on the opposite side of the Sun. A satellite in this type of orbit would relay communications between Earth and Mars during the period of up to several weeks, when direct communication is blocked by the Sun. These orbits are far superior for this purpose when compared to stationing a satellite at one of the Sun-Mars equilateral Lagrangian points, L(4) or L(5), for two reasons. First, L(4) and L(5) are 228 million kilometers from Mars, about 10 times the distance of a spacecraft in one of the MarsSat orbits, and by virtue of the inverse-square law, all other things being equal, the signal strength received at L(4) or L(5) would be one percent of the signal strength received by a spacecraft in one of the MarsSat orbits. Thus, a relay satellite stationed at L(4) or L(5) would have to be that much more powerful to receive data at the same rate, with concomitant increases in spacecraft size and weight. Second, a number of

  4. Synthesis and structural study of samarium hexacyanoferrate (III) tetrahydrate, SmFe(CN) 6·4H 2O

    NASA Astrophysics Data System (ADS)

    Mullica, D. F.; Perkins, Herbert O.; Sappenfield, E. L.; Grossie, David A.

    1988-05-01

    Single crystals of SmFe(CN) 6·4H 2O prepared from an aqueous solution under ambient conditions have been used for single-crystal diffraction, thermal gravimetric analysis, and infrared spectrometric studies. This characterized compound is compared to previously reported LnT(CN) 6 (T =Cr, Fe, Co) structures. Samarium hexacyanoferrate (III) tetrahydrate is found to be monoclinic, not hexagonal or orthorhombic as presupposed. SmFe(CN) 6·4H 2O crystallizes in space group P2/ 1m (No. 11), a = 7.431(1), b = 13.724(3), c = 7.429(2)A˚, β = 119.95(1)°, Z = 2. Full-matrix least-squares refinement has yielded the final values of R = 0.0292 and R w = 0.0296 for 1028 unique reflections. The observed and calculated densities are 2.198(3) and 2.197 Mg m -3, respectively. The dominant feature of the structure is that the samarium ion is eight-coordinated, not nine as previously believed. The samarium ion is bonded to six cyanonitrogen atoms and two water molecules in a square antiprism geometry ( D 4d), the SmN 6(H 2O) 2 group. The FeC 6 group is octahedrally arranged. Cyanide bridging links these groups to build an infinite polymeric array. Additional water molecules are trapped in distorted cubic cages within the structure. The important averaged bond lengths are: Sm sbnd N = 2.505(15); Sm sbnd O = 2.402(1); Fe sbnd C = 1.931(3); and C tbnd N = 1.156(1)A˚.

  5. CloudSat Anomaly Recovery and Operational Lessons Learned

    NASA Technical Reports Server (NTRS)

    Nayak, Michael; Witkowski, Mona

    2012-01-01

    Nov 2011: NASA/JPL declared CloudSat fully operational in DO ]OP Mode . CloudSat collects science data during sunlit portion of orbit, stable spin hibernation in eclipse . New CONOPS requires constant monitoring of thermal and power profiles, while allowing collection of 54 mins of science data per sunlit orbit

  6. SAT and ACT Predict College GPA after Removing "g"

    ERIC Educational Resources Information Center

    Coyle, Thomas R.; Pillow, David R.

    2008-01-01

    This research examined whether the SAT and ACT would predict college grade point average (GPA) after removing g from the tests. SAT and ACT scores and freshman GPAs were obtained from a university sample (N=161) and the 1997 National Longitudinal Study of Youth (N=8984). Structural equation modeling was used to examine relationships among g, GPA,…

  7. Determination of aqueous acid-dissociation constants of aspartic acid using PCM/DFT method

    NASA Astrophysics Data System (ADS)

    Sang-Aroon, Wichien; Ruangpornvisuti, Vithaya

    Determination of acid-dissociation constants, pKa, of aspartic acid in aqueous solution, using density functional theory calculations combined with the conductor-like polarizable continuum model (CPCM) and with integral-equation-formalism polarizable continuum model (IEFPCM) based on the UAKS and UAHF radii, was carried out. The computed pKa values derived from the CPCM and IEFPCM with UAKS cavity model of bare structures of the B3LYP/6-31+G(d,p)-optimized tetrahydrated structures of aspartic acid species are mostly close to the experimental pKa values.0

  8. CubeSat Integration into the Space Situational Awareness Architecture

    NASA Astrophysics Data System (ADS)

    Morris, K.; Wolfson, M.; Brown, J.

    2013-09-01

    Lockheed Martin Space Systems Company has recently been involved in developing GEO Space Situational Awareness architectures, which allows insights into how cubesats can augment the current national systems. One hole that was identified in the current architecture is the need for timelier metric track observations to aid in the chain of custody. Obtaining observations of objects at GEO can be supported by CubeSats. These types of small satellites are increasing being built and flown by government agencies like NASA and SMDC. CubeSats are generally mass and power constrained allowing for only small payloads that cannot typically mimic traditional flight capability. CubeSats do not have a high reliability and care must be taken when choosing mission orbits to prevent creating more debris. However, due to the low costs, short development timelines, and available hardware, CubeSats can supply very valuable benefits to these complex missions, affordably. For example, utilizing CubeSats for advanced focal plane demonstrations to support technology insertion into the next generation situational awareness sensors can help to lower risks before the complex sensors are developed. CubeSats can augment the planned ground and space based assets by creating larger constellations with more access to areas of interest. To aid in maintaining custody of objects, a CubeSat constellation at 500 km above GEO would provide increased point of light tracking that can augment the ground SSA assets. Key features of the Cubesat include a small visible camera looking along the GEO belt, a small propulsion system that allows phasing between CubeSats, and an image processor to reduce the data sent to the ground. An elegant communications network will also be used to provide commands to and data from multiple CubeSats. Additional CubeSats can be deployed on GSO launches or through ride shares to GEO, replenishing or adding to the constellation with each launch. Each CubeSat would take images of

  9. ProSAT+: visualizing sequence annotations on 3D structure.

    PubMed

    Stank, Antonia; Richter, Stefan; Wade, Rebecca C

    2016-08-01

    PRO: tein S: tructure A: nnotation T: ool-plus (ProSAT(+)) is a new web server for mapping protein sequence annotations onto a protein structure and visualizing them simultaneously with the structure. ProSAT(+) incorporates many of the features of the preceding ProSAT and ProSAT2 tools but also provides new options for the visualization and sharing of protein annotations. Data are extracted from the UniProt KnowledgeBase, the RCSB PDB and the PDBe SIFTS resource, and visualization is performed using JSmol. User-defined sequence annotations can be added directly to the URL, thus enabling visualization and easy data sharing. ProSAT(+) is available at http://prosat.h-its.org.

  10. Massively Clustered CubeSats NCPS Demo Mission

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.; Young, David; Kim, Tony; Houts, Mike

    2013-01-01

    Technologies under development for the proposed Nuclear Cryogenic Propulsion Stage (NCPS) will require an un-crewed demonstration mission before they can be flight qualified over distances and time frames representative of a crewed Mars mission. In this paper, we describe a Massively Clustered CubeSats platform, possibly comprising hundreds of CubeSats, as the main payload of the NCPS demo mission. This platform would enable a mechanism for cost savings for the demo mission through shared support between NASA and other government agencies as well as leveraged commercial aerospace and academic community involvement. We believe a Massively Clustered CubeSats platform should be an obvious first choice for the NCPS demo mission when one considers that cost and risk of the payload can be spread across many CubeSat customers and that the NCPS demo mission can capitalize on using CubeSats developed by others for its own instrumentation needs. Moreover, a demo mission of the NCPS offers an unprecedented opportunity to invigorate the public on a global scale through direct individual participation coordinated through a web-based collaboration engine. The platform we describe would be capable of delivering CubeSats at various locations along a trajectory toward the primary mission destination, in this case Mars, permitting a variety of potential CubeSat-specific missions. Cameras on various CubeSats can also be used to provide multiple views of the space environment and the NCPS vehicle for video monitoring as well as allow the public to "ride along" as virtual passengers on the mission. This collaborative approach could even initiate a brand new Science, Technology, Engineering and Math (STEM) program for launching student developed CubeSat payloads beyond Low Earth Orbit (LEO) on future deep space technology qualification missions. Keywords: Nuclear Propulsion, NCPS, SLS, Mars, CubeSat.

  11. Achieving Science with CubeSats: Thinking Inside the Box

    NASA Astrophysics Data System (ADS)

    Zurbuchen, Thomas H.; Lal, Bhavya

    2017-01-01

    We present the results of a study conducted by the National Academies of Sciences, Engineering, and Medicine. The study focused on the scientific potential and technological promise of CubeSats. We will first review the growth of the CubeSat platform from an education-focused technology toward a platform of importance for technology development, science, and commercial use, both in the United States and internationally. The use has especially exploded in recent years. For example, of the over 400 CubeSats launched since 2000, more than 80% of all science-focused ones have been launched just in the past four years. Similarly, more than 80% of peer-reviewed papers describing new science based on CubeSat data have been published in the past five years.We will then assess the technological and science promise of CubeSats across space science disciplines, and discuss a subset of priority science goals that can be achieved given the current state of CubeSat capabilities. Many of these goals address targeted science, often in coordination with other spacecraft, or by using sacrificial or high-risk orbits that lead to the demise of the satellite after critical data have been collected. Other goals relate to the use of CubeSats as constellations or swarms, deploying tens to hundreds of CubeSats that function as one distributed array of measurements.Finally, we will summarize our conclusions and recommendations from this study; especially those focused on nearterm investment that could improve the capabilities of CubeSats toward increased science and technological return and enable the science communities’ use of CubeSats.

  12. Near Earth Network (NEN) CubeSat Communications

    NASA Technical Reports Server (NTRS)

    Schaire, Scott

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit), HEO (Highly Elliptical Orbit), lunar and L1-L2 orbits. The NEN's future mission set includes and will continue to include CubeSat missions. The first NEN-supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into LEO in 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground-based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL)-developed IRIS (Satellite Communication for Air Traffic Management) radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 (Exploration Mission-1) lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NEN's mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1-L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio

  13. CubeSats for Astrophysics: The Current Perspective

    NASA Astrophysics Data System (ADS)

    Ardila, David R.; Shkolnik, Evgenya; Gorjian, Varoujan

    2017-01-01

    Cubesats are small satellites built to multiples of 1U (1000 cm3). The 2016 NRC Report “Achieving Science with CubeSats” indicates that between 2013 and 2018 NASA and NSF sponsored 104 CubeSats. Of those, only one is devoted to astrophysics: HaloSat (PI: P. Kaaret), a 6U CubeSat with an X-ray payload to study the hot galactic halo.Despite this paucity of missions, CubeSats have a lot of potential for astrophysics. To assess the science landscape that a CubeSat astrophysics mission may occupy, we consider the following parameters:1-Wavelength: CubeSats are not competitive in the visible, unless the application (e.g. high precision photometry) is difficult to do from the ground. Thermal IR science is limited by the lack of low-power miniaturized cryocoolers and by the large number of infrared astrophysical missions launched or planned. In the UV, advances in δ-doping processes result in larger sensitivity with smaller apertures. Commercial X-ray detectors also allow for competitive science.2-Survey vs. Pointed observations: All-sky surveys have been done at most wavelengths from X-rays to Far-IR and CubeSats will not be able to compete in sensitivity with them. CubeSat science should then center on specific objects or object classes. Due to poor attitude control, unresolved photometry is scientifically more promising that extended imaging.3-Single-epoch vs. time domain: CubeSat apertures cannot compete in sensitivity with big satellites when doing single-epoch observations. However, time-domain astrophysics is an area in which CubeSats can provide very valuable science return.Technologically, CubeSat astrophysics is limited by:1-Lack of large apertures: The largest aperture CubeSat launched is ~10 cm, although deployable apertures as large as 20 cm could be fitted to 6U buses.2-Poor attitude control: State-of-the-art systems have demonstrated jitter of ~10” on timescales of seconds. Jitter imposes limits on image quality and, coupled with detector errors

  14. Space radiation incident on SATS missions

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.

    1973-01-01

    A special orbital radiation study was conducted in order to evaluate mission encountered energetic particle fluxes. This information is to be supplied to the project subsystem engineers for their guidance in designing flight hardware to withstand the expected radiation levels. Flux calculations were performed for a set of 20 nominal trajectories placed at several altitudes and inclinations. Temporal variations in the ambient electron environment were considered and partially accounted for. Magnetic field calculations were performed with a current field model, extrapolated to the tentative SATS launch epoch with linear time terms. Orbital flux integrations ware performed with the latest proton and electron environment models, using new computational methods. The results are presented in graphical and tabular form. Estimates of energetic solar proton fluxes are given for a one year mission at selected integral energies ranging from 10 to 100 Mev, calculated for a year of maximum solar activity during the next solar cycle.

  15. 3D Printing the Complete CubeSat

    NASA Technical Reports Server (NTRS)

    Kief, Craig

    2015-01-01

    The 3D Printing the Complete CubeSat project is designed to advance the state-of-the-art in 3D printing for CubeSat applications. Printing in 3D has the potential to increase reliability, reduce design iteration time and provide greater design flexibility in the areas of radiation mitigation, communications, propulsion, and wiring, among others. This project is investigating the possibility of including propulsion systems into the design of printed CubeSat components. One such concept, an embedded micro pulsed plasma thruster (mPPT), could provide auxiliary reaction control propulsion for a spacecraft as a means to desaturate momentum wheels.

  16. Atmospheric Entry Aerothermodynamics Flight Test on CubeSat Platform

    NASA Astrophysics Data System (ADS)

    Sakraker, I.; Umit, E.; van der Haegen, V.; Chazot, O.

    2014-06-01

    The challenging aerothermochemistry of atmospheric entry is aimed to be experimented on a triple CubeSat platform having ablative TPS in the front unit and ceramic TPS on the side panels. Five aerothermodynamics payloads are presented in this paper.

  17. Modeling Growth of SAT Reading Performance Using Repeated Measures Data

    ERIC Educational Resources Information Center

    Deng, Hui; Wiley, Andrew

    2008-01-01

    Presented at the Annual National Council on Measurement in Education (NCME) in New York in March 2008. This presentation explores the growth trajectory of the SAT Reading scores and examine what demographics and variation may cause changes and affect growth.

  18. Skunk Works type approach for F-SAT

    NASA Technical Reports Server (NTRS)

    Turner, Gary F.

    1992-01-01

    The topics are presented in viewgraph form and include the following: the F-SAT Program, the classic program organization, design/configuration management, procurement/material, manufacturing, quality assurance, the facility, and personnel management.

  19. Skunk Works type approach for F-SAT

    NASA Astrophysics Data System (ADS)

    Turner, Gary F.

    The topics are presented in viewgraph form and include the following: the F-SAT Program, the classic program organization, design/configuration management, procurement/material, manufacturing, quality assurance, the facility, and personnel management.

  20. Onboard autonomy on the Three Corner Sat Mission

    NASA Technical Reports Server (NTRS)

    Chien, S.; Engelhardt, B.; Knight, R.; Rabideau, G.; Sherwood, R.

    2001-01-01

    Three Corner Sat (3CS) is a mission of three university nanosatellites scheduled for launch on September 2002. The 3CS misison will utilize significan onboard autonomy to perform onboard science data validation and replanning.

  1. Evolution of subterminal satellite (StSat) repeats in hominids.

    PubMed

    Koga, Akihiko; Notohara, Morihiro; Hirai, Hirohisa

    2011-02-01

    Subterminal satellite (StSat) repeats, consisting of 32-bp-long AT-rich units (GATATTTCCATGTT(T/C)ATACAGATAGCGGTGTA), were first found in chimpanzee and gorilla (African great apes) as one of the major components of heterochromatic regions located proximal to telomeres of chromosomes. StSat repeats have not been found in orangutan (Asian great ape) or human. This patchy distribution among species suggested that the StSat repeats were present in the common ancestor of African great apes and subsequently lost in the lineage leading to human. An alternative explanation is that the StSat repeats in chimpanzee and gorilla have different origins and the repeats did not occur in human. The purpose of the present study was quantitative evaluation of the above alternative possibilities by analyzing the nucleotide variation contained in the repeats. We collected large numbers of sequences of repeat units from genome sequence databases of chimpanzee and gorilla, and also bonobo (an African great ape phylogenetically closer to chimpanzee). We then compared the base composition of the repeat units among the 3 species, and found statistically significant similarities in the base composition. These results support the view that the StSat repeats had already formed multiple arrays in the common ancestor of African great apes. It is thus suggested that humans lost StSat repeats which had once grown to multiple arrays.

  2. Miniature scientific-grade magnetic sensors for CubeSats

    NASA Astrophysics Data System (ADS)

    Pronenko, Vira; Belyayev, Serhiy

    2016-07-01

    Micro- and nanosatellites have become more attractive due to their low development and launch cost. A class of nanosatellites defined by the CubeSat standard allows standardizing CubeSat preparation and launch, thus making the projects more affordable. Because of the complexity of sensors miniaturization to install them onboard CubeSat, the majority of CubeSat launches are aimed the technology demonstration or education missions. The scientific success of CubeSat mission depends on the sensors quality. In spite that the sensitivity of the magnetic sensors strongly depends on their size, the recent development in this branch allows us to propose tiny but sensitive both AC and DC magnetometers. The goal of the present report is to introduce the new design of miniature three-component sensors for measurement of vector magnetic fields - for quasi-stationary and slowly fluctuating - flux-gate magnetometer (FGM) - and for alternative ones - search-coil magnetometer (SCM). In order to create magnetometers with the really highest possible level of parameters, a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Construction details and technical specifications of miniature but sensitive FGM and SCM for the CubeSat mission are presented. This work is supported by EC Framework 7 funded project 607197.

  3. PhoneSat In-flight Experience Results

    NASA Technical Reports Server (NTRS)

    Salas, Alberto Guillen; Attai, Watson; Oyadomari, Ken Y.; Priscal, Cedric; Schimmin, Rogan S.; Gazulla, Oriol Tintore; Wolfe, Jasper L.

    2014-01-01

    Over the last decade, consumer technology has vastly improved its performances, become more affordable and reduced its size. Modern day smartphones offer capabilities that enable us to figure out where we are, which way we are pointing, observe the world around us, and store and transmit this information to wherever we want. These capabilities are remarkably similar to those required for multi-million dollar satellites. The PhoneSat project at NASA Ames Research Center is building a series of CubeSat-size spacecrafts using an off-the-shelf smartphone as its on-board computer with the goal of showing just how simple and cheap space can be. Since the PhoneSat project started, different suborbital and orbital flight activities have proven the viability of this revolutionary approach. In early 2013, the PhoneSat project launched the first triage of PhoneSats into LEO. In the five day orbital life time, the nano-satellites flew the first functioning smartphone-based satellites (using the Nexus One and Nexus S phones), the cheapest satellite (a total parts cost below $3,500) and one of the fastest on-board processors (CPU speed of 1GHz). In this paper, an overview of the PhoneSat project as well as a summary of the in-flight experimental results is presented.

  4. Crystal structure of [2-(tri-ethyl-ammonio)-eth-yl][(2,4,6-triiso-propyl-phen-yl)sulfon-yl]amide tetra-hydrate.

    PubMed

    Golz, C; Strohmann, C

    2015-05-01

    The zwitterionic title compound, C23H42N2O2S·4H2O, crystallized as a tetrahydrate from a solution of N-[(2,4,6-triiso-propyl-phen-yl)sulfon-yl]aziridine in tri-ethyl-amine, diethyl ether and pentane in the presence of moist air. It is formed by a nucleophillic ring-opening that is assumed to be reversible. The mol-ecular structure shows a major disorder of the triiso-propyl-phenyl group over two equally occupied locations. An inter-esting feature is the uncommon hydrate structure, exhibiting a tape-like motif which can be classified as a transition of the one-dimensional T4(2)6(2) motif into the two-dimensional L4(6)5(7)6(8) motif.

  5. Science-Driven NanoSats Design for Deep Space

    NASA Astrophysics Data System (ADS)

    Klesh, A. T.; Castillo, J. C.

    2012-12-01

    CubeSat-based exploration of Earth has driven the development of miniaturized systems and research-grade instruments. The current performance of CubeSats raises the question of their potential contribution to planetary exploration. Two possible applications can be foreseen. One would take advantage of the readily availability of the CubeSat deployer Poly Picosatellite Orbital Deployer (P-POD) for planetary-related observations around Earth (e.g., O/OREOS mission, ExoPlanetSat), and, when propulsion systems develop, for interplanetary exploration. However, the CubeSat formfactor restricts payloads to be in an undeployed volume of 10x10x10 (1U) to 10x20x30 (6U) cm, based on the qualified and accepted P-POD. As a possible alternative, one may leverage the CubeSat-tailored subsystems to operate that platform as a secondary payload on a deep space mission. Whether the CubeSat formfactor constraint might be adjusted to accommodate a broader range of science applications or specific tailoring is required remains to be quantified. Through consultation with a wide range of scientists and engineers, we have examined the possible applications of secondary deep space NanoSats, and what derived requirements stem from these missions. Applications and requirements, together with existing technology, inform on common formfactors that could be useful for future planetary missions. By examining these formfactors, we have identified different categories of NanoSat explorer (additionally imposing discrete requirements on the mothership) that directly support scientific endeavors. In this paper, we outline some of the scientific applications that would drive the NanoSat formfactor design, as well as describe how the requirements affect programmatic issues. Several mission types are considered: passive deployment, active propulsion, targeted landing, and sample return. Each scenario changes the risk posture, and can impose additional considerations. Our goal has been to identify

  6. Expanding CubeSat Capabilities with a Low Cost Transceiver

    NASA Technical Reports Server (NTRS)

    Palo, Scott; O'Connor, Darren; DeVito, Elizabeth; Kohnert, Rick; Schaire, Scott H.; Bundick, Steve; Crum, Gary; Altunc, Serhat; Winkert, Thomas

    2014-01-01

    CubeSats have developed rapidly over the past decade with the advent of a containerized deployer system and ever increasing launch opportunities. These satellites have moved from an educational tool to teach students about engineering challenges associated with satellite design, to systems that are conducting cutting edge earth, space and solar science. Early variants of the CubeSat had limited functionality and lacked sophisticated attitude control, deployable solar arrays and propulsion. This is no longer the case and as CubeSats mature, such systems are becoming commercially available. The result is a small satellite with sufficient power and pointing capabilities to support a high rate communication system. Communications systems have matured along with other CubeSat subsystems. Originally developed from amateur radio systems, CubeSats have generally operated in the VHF and UHF bands at data rates below 10 kbps (kilobits per second). More recently higher rate UHF systems have been developed, however these systems require a large collecting area on the ground to close the communications link at 3 Mbps (megabits per second). Efforts to develop systems that operate with similar throughput at S-Band (2-4 GHz (gigaherz)) and C-Band (4-8 GHz (gigaherz)) have also recently evolved. In this paper we outline an effort to develop a high rate CubeSat communication system that is compatible with the NASA Near Earth Network and can be accommodated by a CubeSat. The system will include a 200 kbps (kilobits per second) S-Band receiver and a 12.5 Mbps (megabits per second).X-Band transmitter. This paper will focus on our design approach and initial results associated with the 12.5 Mbps (megabits per second) X-band transmitter.

  7. Solar neutron observations with ChubuSat-2 satellite

    NASA Astrophysics Data System (ADS)

    Yamaoka, Kazutaka

    2016-07-01

    Solar neutron observation is a key in understanding of ion accerelation mechanism in the Sun surface since neutrons are hardly affected by magnetic field around the Sun and intersteller mediums unlike charged particles. However, there was only a few tenth detections so far since its discovery in 1982. Actually SEDA-AP Fiber detector (FIB) onboard the International Space Station (ISS) was suffered from a high neutron background produced by the ISS itself. ChubuSat is a series of 50-kg class microsatellite jointly depeloped by universities (Nagoya university and Daido university) and aerospace companies at the Chubu area of central Japan. The ChubuSat-2 is the second ChubuSat following the ChubuSat-1 which was launched by Russian DNEPR rocket on November 6, 2014. It was selected as one of four piggyback payloads of the X-ray astronomy satellite ASTRO-H in 2014 summer, and will be launched by the H-IIA launch vehcles from from JAXA Tanegashima Space Center (TNSC) in February 2016. The ChubuSat-2 carries a mission instrument, radiation detector (RD). The main mission of ChubuSat-2 is devoted for monitoring neutrons and gamma-rays which can be background source for ASTRO-H celestrial observations with the RD. The mission also involves a function of solar neutron observations which were originally proposed by graduate students who join the leadership development program for space exploration and research, program for leading graduate schools at Nagoya University. The RD has a similar detection area and efficiency to those of the SEDA-AP FIB, but is expected to have lower backgrounthan the ISS thanks to much smaller mass of the micro-satellite. In this paper, we will describe details of ChubuSat-2 satellite and RD, and in-orbit performance of RD.

  8. CubeSat Material Limits for Design for Demise

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.

    2014-01-01

    The CubeSat form factor of nano-satellite (a satellite with a mass between one and ten kilograms) has grown in popularity due to their ease of construction and low development and launch costs. In particular, their use as student led payload design projects has increased due to the growing number of launch opportunities. CubeSats are often deployed as secondary or tertiary payloads on most US launch vehicles or they may be deployed from the ISS. The focus of this study will be on CubeSats launched from the ISS. From a space safety standpoint, the development and deployment processes for CubeSats differ significantly from that of most satellites. For large satellites, extensive design reviews and documentation are completed, including assessing requirements associated with re-entry survivability. Typical CubeSat missions selected for ISS deployment have a less rigorous review process that may not evaluate aspects beyond overall design feasibility. CubeSat design teams often do not have the resources to ensure their design is compliant with re-entry risk requirements. A study was conducted to examine methods to easily identify the maximum amount of a given material that can be used in the construction of a CubeSats without posing harm to persons on the ground. The results demonstrate that there is not a general equation or relationship that can be used for all materials; instead a limiting value must be defined for each unique material. In addition, the specific limits found for a number of generic materials that have been previously used as benchmarking materials for re-entry survivability analysis tool comparison will be discussed.

  9. CloudSat as a Global Radar Calibrator

    SciTech Connect

    Protat, Alain; Bouniol, Dominique; O'Connor, E. J.; Baltink, Henk K.; Verlinde, J.; Widener, Kevin B.

    2011-03-01

    The calibration of the CloudSat spaceborne cloud radar has been thoroughly assessed using very accurate internal link budgets before launch, comparisons with predicted ocean surface backscatter at 94 GHz, direct comparisons with airborne cloud radars, and statistical comparisons with ground-based cloud radars at different locations of the world. It is believed that the calibration of CloudSat is accurate to within 0.5 to 1 dB. In the present paper it is shown that an approach similar to that used for the statistical comparisons with ground-based radars can now be adopted the other way around to calibrate other ground-based or airborne radars against CloudSat and / or detect anomalies in long time series of ground-based radar measurements, provided that the calibration of CloudSat is followed up closely (which is the case). The power of using CloudSat as a Global Radar Calibrator is demonstrated using the Atmospheric Radiation Measurement cloud radar data taken at Barrow, Alaska, the cloud radar data from the Cabauw site, The Netherlands, and airborne Doppler cloud radar measurements taken along the CloudSat track in the Arctic by the RASTA (Radar SysTem Airborne) cloud radar installed in the French ATR-42 aircraft for the first time. It is found that the Barrow radar data in 2008 are calibrated too high by 9.8 dB, while the Cabauw radar data in 2008 are calibrated too low by 8.0 dB. The calibration of the RASTA airborne cloud radar using direct comparisons with CloudSat agrees well with the expected gains and losses due to the change in configuration which required verification of the RASTA calibration.

  10. CubeSat Material Limits For Design for Demise

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.

    2014-01-01

    The CubeSat form factor of nano-satellite (a satellite with a mass between one and ten kilograms) has grown in popularity due to their ease of construction and low development and launch costs. In particular, their use as student led payload design projects has increased due to the growing number of launch opportunities. CubeSats are often deployed as secondary or tertiary payloads on most US launch vehicles or they may be deployed from the ISS. The focus of this study will be on CubeSats launched from the ISS. From a space safety standpoint, the development and deployment processes for CubeSats differ significantly from that of most satellites. For large satellites, extensive design reviews and documentation are completed, including assessing requirements associated with reentry survivability. Typical CubeSat missions selected for ISS deployment have a less rigorous review process that may not evaluate aspects beyond overall design feasibility. CubeSat design teams often do not have the resources to ensure their design is compliant with reentry risk requirements. A study was conducted to examine methods to easily identify the maximum amount of a given material that can be used in the construction of a CubeSats without posing harm to persons on the ground. The results demonstrate that there is not a general equation or relationship that can be used for all materials; instead a limiting value must be defined for each unique material. In addition, the specific limits found for a number of generic materials that have been previously used as benchmarking materials for reentry survivability analysis tool comparison will be discussed.

  11. Isoform-level brain expression profiling of the spermidine/spermine N1-Acetyltransferase1 (SAT1) gene in major depression and suicide.

    PubMed

    Pantazatos, Spiro P; Andrews, Stuart J; Dunning-Broadbent, Jane; Pang, Jiuhong; Huang, Yung-Yu; Arango, Victoria; Nagy, Peter L; John Mann, J

    2015-07-01

    Low brain expression of the spermidine/spermine N-1 acetyltransferase (SAT1) gene, the rate-limiting enzyme involved in catabolism of polyamines that mediate the polyamine stress response (PSR), has been reported in depressed suicides. However, it is unknown whether this effect is associated with depression or with suicide and whether all or only specific isoforms expressed by SAT1, such as the primary 171 amino acid protein-encoding transcript (SSAT), or an alternative splice variant (SSATX) that is involved in SAT1 regulated unproductive splicing and transcription (RUST), are involved. We applied next generation sequencing (RNA-seq) to assess gene-level, isoform-level, and exon-level SAT1 expression differences between healthy controls (HC, N = 29), DSM-IV major depressive disorder suicides (MDD-S, N = 21) and MDD non-suicides (MDD, N = 9) in the dorsal lateral prefrontal cortex (Brodmann Area 9, BA9) of medication-free individuals postmortem. Using small RNA-seq, we also examined miRNA species putatively involved in SAT1 post-transcriptional regulation. A DSM-IV diagnosis was made by structured interview. Toxicology and history ruled out recent psychotropic medication. At the gene-level, we found low SAT1 expression in both MDD-S (vs. HC, p = 0.002) and MDD (vs. HC, p = 0.002). At the isoform-level, reductions in MDD-S (vs. HC) were most pronounced in four transcripts including SSAT and SSATX, while reductions in MDD (vs. HC) were pronounced in three transcripts, one of which was reduced in MDD relative to MDD-S (all p < 0.1 FDR corrected). We did not observe evidence for differential exon-usage (i.e. splicing) nor differences in miRNA expression. Results replicate the finding of low SAT1 brain expression in depressed suicides in an independent sample and implicate low SAT1 brain expression in MDD independent of suicide. Low expressions of both SSAT and SATX isoforms suggest that shared transcriptional mechanisms involved in RUST may account for low SAT1 brain

  12. Systematic review: Comparison of Xpert MTB/RIF, LAMP and SAT methods for the diagnosis of pulmonary tuberculosis.

    PubMed

    Yan, Liping; Xiao, Heping; Zhang, Qing

    2016-01-01

    Technological advances in nucleic acid amplification have led to breakthroughs in the early detection of PTB compared to traditional sputum smear tests. The sensitivity and specificity of loop-mediated isothermal amplification (LAMP), simultaneous amplification testing (SAT), and Xpert MTB/RIF for the diagnosis of pulmonary tuberculosis were evaluated. A critical review of previous studies of LAMP, SAT, and Xpert MTB/RIF for the diagnosis of pulmonary tuberculosis that used laboratory culturing as the reference method was carried out together with a meta-analysis. In 25 previous studies, the pooled sensitivity and specificity of the diagnosis of tuberculosis were 93% and 94% for LAMP, 96% and 88% for SAT, and 89% and 98% for Xpert MTB/RIF. The I(2) values for the pooled data were >80%, indicating significant heterogeneity. In the smear-positive subgroup analysis of LAMP, the sensitivity increased from 93% to 98% (I(2) = 2.6%), and specificity was 68% (I(2) = 38.4%). In the HIV-infected subgroup analysis of Xpert MTB/RIF, the pooled sensitivity and specificity were 79% (I(2) = 72.9%) and 99% (I(2) = 64.4%). In the HIV-negative subgroup analysis for Xpert MTB/RIF, the pooled sensitivity and specificity were 72% (I(2) = 49.6%) and 99% (I(2) = 64.5%). LAMP, SAT and Xpert MTB/RIF had comparably high levels of sensitivity and specificity for the diagnosis of tuberculosis. The diagnostic sensitivity and specificity of three methods were similar, with LAMP being highly sensitive for the diagnosis of smear-positive PTB. The cost effectiveness of LAMP and SAT make them particularly suitable tests for diagnosing PTB in developing countries.

  13. Forecasting Evaluation of WindSat in the Coastal Environment

    NASA Technical Reports Server (NTRS)

    Lee, Thomas F.; Bettenhausen, Mike H.; Hawkins, Jeffrey D.; Richardson, Kim; Jedlovec, Gary; Smith, Matt

    2012-01-01

    WindSat has demonstrated that measurements from polarimetric space-based microwave radiometers can be used to retrieve global ocean surface vector winds. Since the date of launch in 2003, substantial incremental improvements have been made to WindSat data processing, calibration, and retrieval algorithms. The retrievals now have higher resolution, improved wind vector ambiguity removal, and enhanced capability to represent high winds. Utilization of WindSat retrievals (wind vectors, total precipitable water, rainrate and sea surface temperature) will be demonstrated in the context of operational weather forecasting applications, especially the monitoring of topographically-forced winds. Examples will be presented from various parts of the world, including inland seas, midlatitude oceans, the tropics, and the United States. We will illustrate retrievals in extreme high- and extreme low-wind regimes, both of which can be problematic. Rain contamination will be addressed. We will include a comparison of WindSat vector maps to corresponding maps from the QuikScat scatterometer. We will discuss how near-realtime data from WindSat is being transitioned to specific offices within the National Weather Service.

  14. Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT)

    NASA Technical Reports Server (NTRS)

    Brown, Cheryl B.; Conger, Bruce C.; Miranda, Bruno M.; Bue, Grant C.; Rouen, Michael N.

    2007-01-01

    An effort was initiated by NASA/JSC in 2001 to develop an Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT) for the sizing of Extravehicular Activity System (EVAS) architecture and studies. Its intent was to support space suit development efforts and to aid in conceptual designs for future human exploration missions. Its basis was the Life Support Options Performance Program (LSOPP), a spacesuit and portable life support system (PLSS) sizing program developed for NASA/JSC circa 1990. EVAS_SAT estimates the mass, power, and volume characteristics for user-defined EVAS architectures, including Suit Systems, Airlock Systems, Tools and Translation Aids, and Vehicle Support equipment. The tool has undergone annual changes and has been updated as new data have become available. Certain sizing algorithms have been developed based on industry standards, while others are based on the LSOPP sizing routines. The sizing algorithms used by EVAS_SAT are preliminary. Because EVAS_SAT was designed for use by members of the EVA community, subsystem familiarity on the part of the intended user group and in the analysis of results is assumed. The current EVAS_SAT is operated within Microsoft Excel 2003 using a Visual Basic interface system.

  15. FalconSAT-7: a membrane space solar telescope

    NASA Astrophysics Data System (ADS)

    Andersen, Geoff; Asmolova, Olha; McHarg, Matthew G.; Quiller, Trey; Maldonado, Carlos

    2016-07-01

    The US Air Force Academy of Physics has built FalconSAT-7, a membrane solar telescope to be deployed from a 3U CubeSat in LEO. The primary optic is a 0.2m photon sieve - a diffractive element consisting of billions of tiny circular dimples etched into a Kapton sheet. The membrane its support structure, secondary optics, two imaging cameras and associated control, recording electronics are packaged within half the CubeSat volume. Once in space the supporting pantograph structure is deployed, extending out and pulling the membrane flat under tension. The telescope will then be directed at the Sun to gather images at H-alpha for transmission to the ground. We will present details of the optical configuration, operation and performance of the flight telescope which has been made ready for launch in early 2017.

  16. iSat Surface Charging and Thruster Plume Interactions Analysis

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Willis, E.; Minow, J.

    2016-01-01

    NASA is designing the Iodine Satellite (iSAT) cubesat mission to demonstrate operations of an iodine electric thruster system. The spacecraft will be deployed as a secondary payload from a launch vehicle which has not yet been identified so the program must plan for the worst case environments over a range of orbital inclinations. We present results from a NASA and Air Force Charging Analyzer Program (NASCAP-2K) surface charging calculation used to evaluate the effects of charging on the spacecraft and to provide the charging levels at other locations in orbit for a thruster plume interaction analysis for the iSAT mission. We will then discuss results from the thruster interactions analysis using the Electric Propulsion Interactions Code (EPIC). The results of these analyses are being used by the iSAT program for a range of environments that could be encountered when the final mission orbit is selected.

  17. Space Weather Mission of SmartSat Program

    NASA Astrophysics Data System (ADS)

    Akioka, M.; Miyake, W.; Nagatsuma, T.; Ohtaka, K.; Kimura, S.; Goka, T.; Matsumoto, H.; Koshiishi, H.

    2009-06-01

    The SmartSat Program is a collaborative program of government agency (NICT,JAXA) and private sector (MHI) in Japan to develop small satellite about 200 Kg. The space weather experiment of the SmartSat consists of Wide Field CME Imager (WCI), Space Environment Data Acquisition Equipment (SEDA), and mission processor (MP). Both of the instruments will be principal components of the L5 mission. WCI is a imager to track CME as far as earth orbit. CME brightness near earth orbit is expected 1E-15 solar brightness or 1/200 of zodiacal light brightness. To observe such a extreme faint target, we are developing wide field of view camera with very high sensitivity and large dynamic range. These highly challenging experiment and demonstration will be implemented in SmartSat program.

  18. A Comparison of the SOCIT and DebriSat Experiments

    NASA Technical Reports Server (NTRS)

    Ausay, Erick; Blake, Brandon; Boyle, Colleen; Cornejo, Alex; Horn, Alexa; Palma, Kirsten; Pistella, Frank; Sato, Taishi; Todd, Naromi; Zimmerman, Jeffrey; Fitz-Coy, Norman; Liou, J.-C.; Sorge, Marlon; Huynh, Thomas; Opiela, John; Krisko, Paula H.; Cowardin, Heather

    2017-01-01

    This paper explores the differences between, and shares the lessons learned from, two hypervelocity impact experiments critical to the update of orbital debris environment models. The procedures and processes of the fourth Satellite Orbital Debris Characterization Impact Test (SOCIT) were analyzed and related to the ongoing DebriSat experiment. SOCIT was the first hypervelocity impact test designed specifically for satellites in Low Earth Orbit (LEO). It targeted a 1960's U.S. Navy satellite, from which data was obtained to update pre-existing NASA and DOD breakup models. DebriSat is a comprehensive update to these satellite breakup models- necessary since the material composition and design of satellites have evolved from the time of SOCIT. Specifically, DebriSat utilized carbon fiber, a composite not commonly used in satellites during the construction of the US Navy Transit satellite used in SOCIT. Although DebriSat is an ongoing activity, multiple points of difference are drawn between the two projects. Significantly, the hypervelocity tests were conducted with two distinct satellite models and test configurations, including projectile and chamber layout. While both hypervelocity tests utilized soft catch systems to minimize fragment damage to its post-impact shape, SOCIT only covered 65% of the projected area surrounding the satellite, whereas, DebriSat was completely surrounded cross-range and downrange by the foam panels to more completely collect fragments. Furthermore, utilizing lessons learned from SOCIT, DebriSat's post-impact processing varies in methodology (i.e., fragment collection, measurement, and characterization). For example, fragment sizes were manually determined during the SOCIT experiment, while DebriSat utilizes automated imaging systems for measuring fragments, maximizing repeatability while minimizing the potential for human error. In addition to exploring these variations in methodologies and processes, this paper also presents the

  19. COLD-SAT orbital experiment configured for Atlas launch

    NASA Technical Reports Server (NTRS)

    Shuster, J. R.; Bennett, F. O.; Wachter, J. P.

    1989-01-01

    The design and requirements for the proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer (COLD-SAT) satellite experiment, which is to be launched by Atlas I, are examined. The COLD-SAT experiments are categorized as class I and II; class I involves technology related to space transportation missions and class II represents alternative fluid management operations and data. The hardware for the COLD-SAT experiments consists of three hydrogen tanks contained in the experimental module; the experimental module is connected to a three-axis-controlled spacecraft bus, and thrusters are positioned on the forward and aft ends of the spacecraft and on the cylindrical portion of the experimental module. The components and systems of the experiment module and the types of experiments that can be conducted in each tank are described. Diagrams of the spacecraft configuration are provided.

  20. HaloSat: A CubeSat to Map the Distribution of Baryonic Matter in the Galactic Halo

    NASA Astrophysics Data System (ADS)

    Miles, Drew M.

    2016-04-01

    Approximately half of predicted baryonic matter in the Milky Way remains unidentified. One possible explanation for the location of this missing matter is in an extended Galactic halo. HaloSat is a CubeSat that aims to constrain the mass and distribution of the halo’s baryonic matter by obtaining an all-sky map of O VII and O VIII emission in the hot gas associated with the halo of the Milky Way. HaloSat offers an improvement in the quality of measurements of oxygen line emission over existing X-ray observatories and an observation plan dedicated to mapping the hot gas in the Galactic halo. In addition to the missing baryon problem, HaloSat will assign a portion of its observations to the solar wind charge exchange (SWCX) in order to calibrate models of SCWX emission. We present here the current status of HaloSat and the progression of instrument development in anticipation of a 2018 launch.

  1. Experimental infection of giraffe (Giraffa camelopardalis) with SAT-1 and SAT-2 foot-and-mouth disease virus.

    PubMed

    Vosloo, W; Swanepoel, S P; Bauman, M; Botha, B; Esterhuysen, J J; Boshoff, C I; Keet, D F; Dekker, A

    2011-04-01

    The potential role of giraffe (Giraffa camelopardalis) in the epidemiology and spread of foot-and-mouth disease (FMD) SAT types was investigated by experimental infection and detection of virus in excretions using virus isolation on primary pig kidney cell cultures. In two experiments separated by a period of 24 months, groups of four animals were needle infected with a SAT-1 or SAT-2 virus, respectively and two in-contact controls were kept with each group. Viraemia was detected 3-9 days post-infection and virus isolated from mouth washes and faeces only occasionally up to day 13. The SAT-1 virus was transmitted to only one in-contact control animal, probably via saliva that contained virus from vesicles in the mouth of a needle-infected animal. None of the animals infected with the SAT-2 virus had any vesicles in the mouth, and there was no evidence of transmission to the in-contact controls. No virus was detected in probang samples for the duration of the experiments (60 days post-infection), indicating that persistent infection probably did not establish with either of these isolates. Giraffe most likely do not play an important role in FMD dissemination. Transmission of infection would possibly occur only during close contact with other animals when mouth vesicles are evident.

  2. LifeSat - A satellite for space biological research

    NASA Technical Reports Server (NTRS)

    Halstead, Thora W.; Morey-Holton, Emily R.

    1990-01-01

    The LifeSat Program addresses the need for continuing access by biological scientists to space experimentation by accommodating a wide range of experiments involving animals and plants for durations up to 60 days in an unmanned satellite. The program will encourage interdisciplinary and international cooperation at both the agency and scientist levels, and will provide a recoverable, reusable facility for low-cost missions addressing key scientific issues that can only be answered by space experimentation. It will provide opportunities for research in gravitational biology and on the effects of cosmic radiation on life systems. The scientific aspects of LifeSat are addressed here.

  3. Radiation Tolerant, FPGA-Based SmallSat Computer System

    NASA Technical Reports Server (NTRS)

    LaMeres, Brock J.; Crum, Gary A.; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Radiation Tolerant, FPGA-based SmallSat Computer System (RadSat) computing platform exploits a commercial off-the-shelf (COTS) Field Programmable Gate Array (FPGA) with real-time partial reconfiguration to provide increased performance, power efficiency and radiation tolerance at a fraction of the cost of existing radiation hardened computing solutions. This technology is ideal for small spacecraft that require state-of-the-art on-board processing in harsh radiation environments but where using radiation hardened processors is cost prohibitive.

  4. Integrated Solar-Panel Antenna Array for CubeSats

    NASA Technical Reports Server (NTRS)

    Baktur, Reyhan

    2016-01-01

    The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

  5. Mars Moons Prospector Mission with CubeSats

    NASA Astrophysics Data System (ADS)

    Udrea, Bogdan; Nayak, Mikey; Allen, Brett; Bourke, Justin; Casariego, Gabriela; Gosselin, Steven; Hiester, Evan; Maier, Margaret; Melchert, Jeanmarie; Patel, Chitrang; Reis, Leslie; Smith, Gregory; Snow, Travis; Williams, Sarah; Franquiz, Francsico

    2015-04-01

    The preliminary design of a low-cost Discovery class mission for prospecting Mars moons Phobos and Deimos is undertaken as capstone senior design class in spacecraft design. The mission design is centred on a mothership that carries a dozen of 12U CubeSats, each of 22x22x34cm in size and 24kg in mass. The mothership is equipped with a set of instruments for the investigation of regolith samples, similar to those with identical functions on the Curiosity and the Mars 2020 rovers. The mothership also serves as a telecommunication hub with Earth. Six of the CubeSats have the role of touching down and picking up soil samples for delivery to the mothership for analysis and the six have the role of visually inspecting the moon at close proximity in visible and near and mid infrared light and deploying instruments on the surface of the moons. A suite of miniaturized instruments are investigated for deployment on the CubeSats. The CubeSats are designed to dock with the mothership to be refueled and they heavily leverage the design of the ARAPAIMA (www.eraucubesat.org) proximity operations 6U CubeSat currently in development at ERAU for the Air Force University Nanosatellite Program. The concept of operations envisions the launch of the mothership as a primary payload on a Mars transfer trajectory. After performing a Mars capture maneuver the mothership undertakes autonomous aerobraking to achieve a highly elliptic orbit with the apoapsis at Deimos altitude of 23,460km. Further maneuvering places the mothership in a relative orbit about Deimos from which the CubeSats are deployed. Once the investigation of Deimos is completed the mothership retrieves its CubeSats and maneuver to achieve a relative orbit about Phobos. An investigation similar to that of Deimos is performed. If the mass margins allow it then an extended mission will attempt to confirm the presence of a dust ring between Phobos and Deimos and conduct multi-point atmospheric investigations with supplemental 3U

  6. CryoSat Plus For Oceans: an ESA Project for CryoSat-2 Data Exploitation Over Ocean

    NASA Astrophysics Data System (ADS)

    Benveniste, J.; Cotton, D.; Clarizia, M.; Roca, M.; Gommenginger, C. P.; Naeije, M. C.; Labroue, S.; Picot, N.; Fernandes, J.; Andersen, O. B.; Cancet, M.; Dinardo, S.; Lucas, B. M.

    2012-12-01

    The ESA CryoSat-2 mission is the first space mission to carry a space-borne radar altimeter that is able to operate in the conventional pulsewidth-limited (LRM) mode and in the novel Synthetic Aperture Radar (SAR) mode. Although the prime objective of the Cryosat-2 mission is dedicated to monitoring land and marine ice, the SAR mode capability of the Cryosat-2 SIRAL altimeter also presents the possibility of demonstrating significant potential benefits of SAR altimetry for ocean applications, based on expected performance enhancements which include improved range precision and finer along track spatial resolution. With this scope in mind, the "CryoSat Plus for Oceans" (CP4O) Project, dedicated to the exploitation of CryoSat-2 Data over ocean, supported by the ESA STSE (Support To Science Element) programme, brings together an expert European consortium comprising: DTU Space, isardSAT, National Oceanography Centre , Noveltis, SatOC, Starlab, TU Delft, the University of Porto and CLS (supported by CNES),. The objectives of CP4O are: - to build a sound scientific basis for new scientific and operational applications of Cryosat-2 data over the open ocean, polar ocean, coastal seas and for sea-floor mapping. - to generate and evaluate new methods and products that will enable the full exploitation of the capabilities of the Cryosat-2 SIRAL altimeter , and extend their application beyond the initial mission objectives. - to ensure that the scientific return of the Cryosat-2 mission is maximised. In particular four themes will be addressed: -Open Ocean Altimetry: Combining GOCE Geoid Model with CryoSat Oceanographic LRM Products for the retrieval of CryoSat MSS/MDT model over open ocean surfaces and for analysis of mesoscale and large scale prominent open ocean features. Under this priority the project will also foster the exploitation of the finer resolution and higher SNR of novel CryoSat SAR Data to detect short spatial scale open ocean features. -High Resolution Polar

  7. A CubeSat for Calibrating Ground-Based and Sub-Orbital Millimeter-Wave Polarimeters (CalSat)

    NASA Astrophysics Data System (ADS)

    Johnson, Bradley R.; Vourch, Clement J.; Drysdale, Timothy D.; Kalman, Andrew; Fujikawa, Steve; Keating, Brian; Kaufman, Jon

    2015-10-01

    We describe a low-cost, open-access, CubeSat-based calibration instrument that is designed to support ground-based and sub-orbital experiments searching for various polarization signals in the cosmic microwave background (CMB). All modern CMB polarization experiments require a robust calibration program that will allow the effects of instrument-induced signals to be mitigated during data analysis. A bright, compact and linearly polarized astrophysical source with polarization properties known to adequate precision does not exist. Therefore, we designed a space-based millimeter-wave calibration instrument, called CalSat, to serve as an open-access calibrator, and this paper describes the results of our design study. The calibration source on board CalSat is composed of five “tones” with one each at 47.1, 80.0, 140, 249 and 309GHz. The five tones we chose are well matched to (i) the observation windows in the atmospheric transmittance spectra, (ii) the spectral bands commonly used in polarimeters by the CMB community and (iii) the Amateur Satellite Service bands in the Table of Frequency Allocations used by the Federal Communications Commission. CalSat would be placed in a polar orbit allowing visibility from observatories in the Northern Hemisphere, such as Mauna Kea in Hawaii and Summit Station in Greenland, and the Southern Hemisphere, such as the Atacama Desert in Chile and the South Pole. CalSat also would be observable by balloon-borne instruments launched from a range of locations around the world. This global visibility makes CalSat the only source that can be observed by all terrestrial and sub-orbital observatories, thereby providing a universal standard that permits comparison between experiments using appreciably different measurement approaches.

  8. The Shrinking Black-White Gap on SAT II Achievement Tests.

    ERIC Educational Resources Information Center

    Journal of Blacks in Higher Education, 2002

    2002-01-01

    Recent research shows that the SAT II test is a much better predictor of college success than the standard SAT. In recent years, black students appear to be making progress in closing the racial scoring gap on the wide variety of academic subjects (particularly chemistry, world history, and biology) that are measured by the SAT II test. (SM)

  9. The Effect of Personality Preferences on the 2005 Version of the SAT

    ERIC Educational Resources Information Center

    Burrs, Ashley

    2013-01-01

    Some researchers suggest the Scholastic Aptitude Test (SAT) is biased toward certain personality types. Extant literature lacked examination of personality constructs and their relationship with SAT scores of the newly revised SAT. The purpose of this study was two-fold. First, this study examined the relationship between the Sensing and Intuition…

  10. Analysis of WindSat Data over Arctic Sea Ice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The radiation of the 3rd and 4th Stokes components emitted by Arctic sea ice and observed by the spaceborne fully polarimetric radiometer WindSat is investigated. Two types of analysis are carried out, spatial (maps of different quadrants of azimuth look angles) and temporal (time series of daily av...

  11. The COLD-SAT experiment for cryogenic fluid management technology

    NASA Technical Reports Server (NTRS)

    Schuster, J. R.; Wachter, J. P.; Vento, D. M.

    1990-01-01

    The COLD-SAT spacecraft design experiments are described. COLD-SAT will be placed into an initial 1300 km circular orbit by an Atlas commercial launch vehicle. Electric power, experiment control and data management, attitude control, and propulsive accelarations for the experiments will be provided by the three-axis-controlled spacecraft bus. To provide data on the effects that low gravity levels might have on the heat and mass transfer processes involved, low levels of accelaration will be created. The COLD-SAT experiment will be configured into a module. The spacecraft experiment module will include three liquid hydrogen tanks; fluid transfer, pressurization and venting equipment; and instrumentation. Since the largest tank has helium-purged MLI to prevent ingress and freezing of air on the launchpad, it will contain all the liquid hydrogen at the point of launching. The hydrogen tanking system used for the Centaur upper stage of the Atlas will load and top off this tank. Atlas, with its liquid hydrogen upper stage, large payload fairing, and large launch margin, simplifies COLD-SAT design and integration.

  12. WindSat Global Soil Moisture Retrieval and Validation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A physically based six-channel land algorithm is developed to simultaneously retrieve the global soil moisture, vegetation water content and land surface temperature. The algorithm is based on a maximum-likelihood estimation and uses WindSat passive microwave data at 10, 18.7 and 37 GHz. The global ...

  13. CloudSat Reflectivity Data Visualization Inside Hurricanes

    NASA Technical Reports Server (NTRS)

    Suzuki, Shigeru; Wright, John R.; Falcon, Pedro C.

    2011-01-01

    We have presented methods to rapidly produce visualization and outreach products from CloudSat data for science and the media These methods combine data from several sources in the product generation process In general, the process can be completely automatic, producing products and notifying potential users

  14. Patterns of SAT Scores, Choice of STEM Major, and Gender

    ERIC Educational Resources Information Center

    Davison, Mark L.; Jew, Gilbert B.; Davenport, Ernest C., Jr.

    2014-01-01

    Using Baccalaureate and Beyond 2001 data, we found that STEM major was associated with an SAT pattern less common among females than males, in which the student's quantitative score exceeded the verbal score. Verbal ability was negatively associated with STEM major. Implications for career theory and test interpretation are discussed.

  15. S.A.T. Drop: Let's Ban the Bomb Theory.

    ERIC Educational Resources Information Center

    American School Board Journal, 1983

    1983-01-01

    Questions radiological physicist Ernest J. Sternglass's theory that links falling Scholastic Aptitude Test (SAT) scores in the 1960s and '70s to nuclear weapons testing in the late '40s, the '50s, and early '60s. Notes other scientists' contention that Sternglass's theory only establishes a correlation, not a cause and effect relationship. (JBM)

  16. The CarbonSat End-to-End Simulator

    NASA Astrophysics Data System (ADS)

    Bramstedt, Klaus; Noel, Stefan; Bovensmann, Heinrich; Reuter, Max; Burrows, John P.; Jurado Lozano, Pedro Jose; Meijer, Yasjka; Loescher, Armin; Acarreta, Juan R.; Sturm, Philipp; Tesmer, Volker; Sanchez Monero, Ana Maria; Atapuerca Rodreiguez de Dios, Francisco Javier; Toledano Sanchez, Daniel; Boesch, Hartmut

    2016-08-01

    The objective of the CarbonSat mission is to improve our knowledge on natural and anthropogenic sources and sinks of CO2 and CH4. CarbonSat was one of the two candidate missions selected for definition studies for becoming Earth Explorer 8 (EE8).The CarbonSat End-to-End Simulator (CSE2ES) simulates the full data flow of the mission with a set of modules embedded in ESA's generic simulation framework OpenSF. A Geometry Module (GM) defines the orbital geometry and related parameters. A Scene Generation Module (SGM) provides simulated radiances and irradiances for the selected scenes. The Level 1 Module (L1M) compromises the instrument simulator and the Level 1b processor, and provide as main output calibrated spectra. The L1M is implemented in two versions, reflecting the instrument concepts from the two competing industrial system studies. The Level 2 Retrieval Module (L2M) performs the retrieval from the input level 1b spectra to the atmospheric parameters (CO2 and CH4).In this paper, we show sensitivity studies with respect to atmospheric parameters, simulations along the orbit and a case study for the detection of a point source emitting carbon dioxide. In summary, the end-to-end simulation with CSE2ES proves the capability of the CarbonSat concept to reach its requirements.

  17. Behind the SAT-Optional Movement: Context and Controversy

    ERIC Educational Resources Information Center

    Epstein, Jonathan P.

    2009-01-01

    The advent of the modern form of the Scholastic Aptitude Test (SAT), brought to bear by the combination of the Educational Testing Service (ETS) and Harvard's former president James Bryant Conant (Lemann 1999), was designed to promote the recognition of talent and intellect, wherever they may be found. Their aim was to provide greater educational…

  18. An Assessment of the Dimensionality of SAT-Mathematical.

    ERIC Educational Resources Information Center

    Lawrence, Ida M.; Dorans, Neil J.

    Six editions of Scholastic Aptitude Test-Mathematical (SAT-M) were factor analyzed using confirmatory and exploratory methods. Confirmatory factor analyses (using the LISREL VI program) were conducted on correlation matrices among item parcels--sums of scores on a small subset of items. Item parcels were constructed to yield correlation matrices…

  19. Two Professors Retake the SAT: Is It a Good Test?

    ERIC Educational Resources Information Center

    Harper, Christopher; Vanderbei, Robert J.

    2009-01-01

    In this article, two professors retake the college-entrance exam and arrive at very different conclusions about its performance. Even though Christopher Harper has worked as a college professor for 15 years, he decided last winter to take the SAT and ACT examinations that his students needed to enter the institution where he teaches, Temple…

  20. Smart Sat experiment for the L5 mission

    NASA Astrophysics Data System (ADS)

    Akioka, M.; Ohtaka, K.; Nagatsuma, T.; Miyake, W.; Goka, T.; Matsumoto, H.; Koshiishi, H.

    We have proposed the L5 mission for space weather research and operational forecasting experiment. The spacecraft will be deployed at the L5 Point of the Sun - Earth system for remote sensing of the Sun and the interplanetary space and for in situ measurement of the solar wind plasma and high energy solar particle event. For the L5 mission, CRL and JAXA develop wide field imager for CME tracking and advanced high energy particle sensor. We plan orbital demonstration in near earth orbit before the L5 mission as the Smart Sat program. The Smart Sat is a pair of small satellites about 150Kg, which will be a collaborative program of government agency (CRL,JAXA) and private sector (MHI) in Japan. The space weather experiment of the Smart Sat consists of Wide field imager for CME tracking (WCI) and Space Environment Data Acquisition equipment (SEDA). Both of the instruments will be principal components of the L5 mission. In this article, we report an overview of the space weather experiment of Smart Sat program.

  1. SmartSat Experiment for the L5 Mission

    NASA Astrophysics Data System (ADS)

    Nagatsuma, T.; Akioka, M.; Ohtaka, K.; Miyake, W.; Goka, T.; Matsumoto, H.; Koshiishi, H.

    2004-12-01

    We have planned the L5 mission for space weather research and operational forecasting experiment. In this mission, a spacecraft will be deployed at the L5 point of the Sun - Earth system for remote sensing of the Sun and the interplanetary space, and for in-situ measurements of the solar wind plasma and high energy particles. For this mission, NICT and JAXA develop wide field imager for tracking CME propagation from the Sun to the Earth and advanced high-energy particle sensor for monitoring of solar particle events, respectively. Before proceeding the L5 mission, we are planning orbital demonstration in GTO using a platform of small satellite, called "SmartSat". The SmartSat program is a collaborative program of government agencies (NICT and JAXA), and a private company (Mitsubishi Heavy Industry) in Japan. The wide field coronal imager (WCI) and space environment data acquisition experiment (SEDA) will be tested by this program as the space weather experiment, since both of the instruments will be principal components of the L5 mission. The SmartSat is planned to be launched by 2007, about 1 year after the launch of STEREO spacecrafts. Therefore, we are expecting the coordinated observation with STEREO mission. In this paper, we will report an overview of the space weather experiment in SmartSat program.

  2. A University Looks at the College Board's Redesigned SAT

    ERIC Educational Resources Information Center

    Turner, Ronné Patrick

    2014-01-01

    As an institution that receives close to 50,000 applications for the 2,800 spaces for the first-year entering class, Northeastern University took special interest in the College Board's March 5 announcement on the SAT redesign. In this article, associate vice president of enrollment and dean of admissions at Northeastern, Ronné Turner, describes…

  3. A Better SAT Starts with a Better College Board

    ERIC Educational Resources Information Center

    Katzman, John

    2014-01-01

    It is so easy to criticize the SAT that most observers overlook the weaknesses of its architect, the College Board. This author contents that, until the latter is replaced, however, the former will never be fixed. The College Board has every incentive to create a complex, stressful, expensive college admissions system. Because it is accountable to…

  4. Beyond Individual Differences: Exploring School Effects on SAT Scores

    ERIC Educational Resources Information Center

    Everson, Howard T.; Millsap, Roger E.

    2004-01-01

    This article explores the complex, hierarchical relation among school characteristics, individual differences in academic achievement, extracurricular activities, and socioeconomic background on performance on the verbal and mathematics Scholastic Aptitude Test (SAT). Using multilevel structural equation models (SEMs) with latent means, we…

  5. Project ELaNa and NASA's CubeSat Initiative

    NASA Technical Reports Server (NTRS)

    Skrobot, Garrett Lee

    2010-01-01

    This slide presentation reviews the NASA program to use expendable lift vehicles (ELVs) to launch nanosatellites for the purpose of enhancing educational research. The Education Launch of Nanosatellite (ELaNa) project, run out of the Launch Services Program is requesting proposals for CubeSat type payload to provide information that will aid or verify NASA Projects designs while providing higher educational research

  6. Malaria Early Warning: The MalarSat project

    NASA Astrophysics Data System (ADS)

    Roca, M.; Escorihuela, M. J.; Martínez, D.; Torrent, M.; Aponte, J.; Nunez, F.; Garcia, J.

    2009-04-01

    Malaria is one of the major public health challenges undermining development in the world. The aim of MalarSat Project is to provide a malaria risks infection maps at global scale using Earth Observation data to support and prevent epidemic episodes. The proposed service for creating malaria risk maps would be critically useful to improve the efficiency in insecticide programs, vaccine campaigns and the logistics epidemic treatment. Different teams have already carried out studies in order to exploit the use of Earth Observation (EO) data with epidemiology purposes. In the case of malaria risk maps, it has been shown that meteorological data is not sufficient to fulfill this objective. In particular being able to map the malaria mosquito habitat would increase the accuracy of risk maps. The malaria mosquitoes mainly reproduce in new water puddles of very reduced dimensions (about 1 meter wide). There is no instrument that could detect such small patches of water unless there are many of them spread in an area of several hundreds of meters. MalarSat aims at using the radar altimeter data from the EnviSat, RA-2, to try and build indicators of mosquitoes existence. This presentation will show the scientific objectives and principles of the MalarSat project.

  7. Validation Experiments supporting the CryoSat-2 mission

    NASA Astrophysics Data System (ADS)

    Cullen, R.; Davidson, M.; Wingham, D.

    2009-12-01

    The primary goals of CryoSat are to derive improved estimates of the rates of change concerning land ice elevation and sea ice thickness and freeboard of the Earth’s land and marine ice fields. Validating such retrievals derived from a phase coherent pulse-width limited polar observing radar altimeter such as SIRAL, the primary payload of CryoSat, is not a simple one. In order to understand all the respective error co-variances it is necessary to acquire many different types of in-situ measurements (GPR, neutron probe density profiles, drilled and electromagnetic derived sea-ice thicknesses, for example) in highly inhospitable regions of the cryosphere at times of the year to detect relevant signals. In order to correlate retrievals from CryoSat with the in-situ data it was decided early in the CryoSat development that an aircraft borne radar altimeter with similar functionality to SIRAL would provide the necessary link, albeit on the smaller scale, and provide pre-launch incite into expected performances. In 2001 ESA commenced the development of its own prototype radar altimeter that mimics the functionality of SIRAL to be operated along-side an airborne laser scanner. Similar to SIRAL, but with subtle functional differences, the airborne SAR/Interferometric Radar Altimeter System (ASIRAS) has now been the centre piece instrument for a number of large scale land and sea ice field campaigns in the Arctic during spring and autumn 2004 and 2006 and 2008. Additional smaller science/test campaigns have taken place in March 2003 (Svalbard), March 2005 (Bay of Bothnia), March 2006 (Western Greenland) and April 2007 (CryoVEx 2007 in Svalbard). It is a credit to all parties that constitute the CryoSat Validation and Retrieval Team (CVRT) for the coordination, planning, acquisition of in-situ and airborne measurements and the subsequent processing and distributing of its data for analysis. CVRT has a robust infrastructure in place for validating and providing measures of

  8. X-Band CubeSat Communication System Demonstration

    NASA Technical Reports Server (NTRS)

    Altunc, Serhat; Kegege, Obadiah; Bundick, Steve; Shaw, Harry; Schaire, Scott; Bussey, George; Crum, Gary; Burke, Jacob C.; Palo, Scott; O'Conor, Darren

    2015-01-01

    Today's CubeSats mostly operate their communications at UHF- and S-band frequencies. UHF band is presently crowded, thus downlink communications are at lower data rates due to bandwidth limitations and are unreliable due to interference. This research presents an end-to-end robust, innovative, compact, efficient and low cost S-band uplink and X-band downlink CubeSat communication system demonstration between a balloon and a Near Earth Network (NEN) ground system. Since communication systems serve as umbilical cords for space missions, demonstration of this X-band communication system is critical for successfully supporting current and future CubeSat communication needs. This research has three main objectives. The first objective is to design, simulate, and test a CubeSat S- and X-band communication system. Satellite Tool Kit (STK) dynamic link budget calculations and HFSS Simulations and modeling results have been used to trade the merit of various designs for small satellite applications. S- and X-band antennas have been tested in the compact antenna test range at Goddard Space Flight Center (GSFC) to gather radiation pattern data. The second objective is simulate and test a CubeSat compatible X-band communication system at 12.5Mbps including S-band antennas, X-band antennas, Laboratory for Atmospheric and Space Physics (LASP) /GSFC transmitter and an S-band receiver from TRL-5 to TRL-8 by the end of this effort. Different X-band communication system components (antennas, diplexers, etc.) from GSFC, other NASA centers, universities, and private companies have been investigated and traded, and a complete component list for the communication system baseline has been developed by performing analytical and numerical analysis. This objective also includes running simulations and performing trades between different X-band antenna systems to optimize communication system performance. The final objective is to perform an end-to-end X-band CubeSat communication system

  9. LEDsats: LEO CubeSats with LEDs for Optical Tracking

    NASA Astrophysics Data System (ADS)

    Seitzer, P.; Cutler, J.; Piergentili, F.; Santoni, F.; Arena, L.; Cardona, T.; Cowardin, H.; Lee, C.; Sharma, S.

    2016-09-01

    We describe a project to launch 1U CubeSats equipped with Light Emitting Diodes (LEDs) into Low Earth Orbit (LEO) for optical tracking with ground-based telescopes. Active illumination on the satellites increases tremendously the number of passes where the LEO satellite is visible when the ground-based telescope is in darkness. The restriction that the satellite is in direct Sun is removed, and so tracking can take place all night long rather than just in twilight. The inspiration for this project came from the Japanese CubeSat FITSAT-1 that carried red and green high-powered LED arrays, and was clearly visible from the ground with small telescopes. There are two goals: 1) increase the accuracy and precision of LEO orbits by increasing the number and length of passes that satellite is visible, and 2) minimize the confusion between objects in the case of multiple CubeSats being launched at the same time. Technical issues to be discussed include the power level required for detection by small (20 - 40 cm) ground based telescopes, the optimum flash pattern for astrometry against star fields, and the timing of the flash pattern to millisecond or better accuracy and precision. We propose to deploy two such LEDsats simultaneously from the International Space Station: the first to be built at the University of Michigan, and the second to be built at Sapienza University Rome. One experiment is to see how we can distinguish these two CubeSats shortly after deployment solely from optical tracking, and so the CubeSats will have different flash patterns.

  10. CloudSat Anomaly Recovery and Operational Lessons Learned

    NASA Technical Reports Server (NTRS)

    Witkowski, Mona; Vane, Deborah; Livermore, Thomas; Rokey, Mark; Barthuli, Marda; Gravseth, Ian J.; Pieper, Brian; Rodzinak, Aaron; Silva, Steve; Woznick, Paul; Nayak, Michael

    2012-01-01

    In April 2011, NASA's pioneering cloud profiling radar satellite, CloudSat, experienced a battery anomaly that placed it into emergency mode and rendered it operations incapable. All initial attempts to recover the spacecraft failed as the resultant power limitations could not support even the lowest power mode. Originally part of a six-satellite constellation known as the "A-Train", CloudSat was unable to stay within its assigned control box, posing a threat to other A-Train satellites. CloudSat needed to exit the constellation, but with the tenuous power profile, conducting maneuvers was very risky. The team was able to execute a complex sequence of operations which recovered control, conducted an orbit lower maneuver, and returned the satellite to safe mode, within one 65 minute sunlit period. During the course of the anomaly recovery, the team developed several bold, innovative operational strategies. Details of the investigation into the root-cause and the multiple approaches to revive CloudSat are examined. Satellite communication and commanding during the anomaly are presented. A radical new system of "Daylight Only Operations" (DO-OP) was developed, which cycles the payload and subsystem components off in tune with earth eclipse entry and exit in order to maintain positive power and thermal profiles. The scientific methodology and operational results behind the graduated testing and ramp-up to DO-OP are analyzed. In November 2011, the CloudSat team successfully restored the vehicle to consistent operational collection of cloud radar data during sunlit portions of the orbit. Lessons learned throughout the six-month return-to-operations recovery effort are discussed and offered for application to other R&D satellites, in the context of on-orbit anomaly resolution efforts.

  11. Shields-1, A SmallSat Radiation Shielding Technology Demonstration

    NASA Technical Reports Server (NTRS)

    Thomsen, D. Laurence, III; Kim, Wousik; Cutler, James W.

    2015-01-01

    The NASA Langley Research Center Shields CubeSat initiative is to develop a configurable platform that would allow lower cost access to Space for materials durability experiments, and to foster a pathway for both emerging and commercial-off-the-shelf (COTS) radiation shielding technologies to gain spaceflight heritage in a relevant environment. The Shields-1 will be Langleys' first CubeSat platform to carry out this mission. Radiation shielding tests on Shields-1 are planned for the expected severe radiation environment in a geotransfer orbit (GTO), where advertised commercial rideshare opportunities and CubeSat missions exist, such as Exploration Mission 1 (EM-1). To meet this objective, atomic number (Z) graded radiation shields (Zshields) have been developed. The Z-shield properties have been estimated, using the Space Environment Information System (SPENVIS) radiation shielding computational modeling, to have 30% increased shielding effectiveness of electrons, at half the thickness of a corresponding single layer of aluminum. The Shields-1 research payload will be made with the Z-graded radiation shields of varying thicknesses to create dose-depth curves to be compared with baseline materials. Additionally, Shields-1 demonstrates an engineered Z-grade radiation shielding vault protecting the systems' electronic boards. The radiation shielding materials' performances will be characterized using total ionizing dose sensors. Completion of these experiments is expected to raise the technology readiness levels (TRLs) of the tested atomic number (Z) graded materials. The most significant contribution of the Z-shields for the SmallSat community will be that it enables cost effective shielding for small satellite systems, with significant volume constraints, while increasing the operational lifetime of ionizing radiation sensitive components. These results are anticipated to increase the development of CubeSat hardware design for increased mission lifetimes, and enable

  12. Spacecraft Charging Analysis of a CubeSat

    NASA Technical Reports Server (NTRS)

    Willis, Emily M.; Minow, Joseph I.; Parker, Linda Neergaard

    2014-01-01

    Spacecraft charging occurs when charged particles from the surrounding space plasma environment contact a spacecraft and unequal charging currents result in a net charge density accumulation on or in spacecraft materials. Charging becomes a threat when differential potentials between two points on the spacecraft or between the spacecraft and the ambient space environment build to the level that electric fields associated with the potentials exceed the electric breakdown strength of the spacecraft materials and electrostatic discharge arcs are generated. Electrostatic discharges resulting from spacecraft charging can adversely affect telemetry and cause irreparable damage to electronics. Other spacecraft charging effects include damage of solar arrays and thermal protection, enhancement of contamination of surfaces, and degradation of optics. Typically, the large government and commercial space programs include spacecraft charging analysis as part of the design process. CubeSat projects, however, usually do not have the time or funding to include a spacecraft charging analysis due to their low budget and quick-turnaround requirements. CubeSat projects also tend to rely heavily on commercial "off-the-shelf" products, many of which are not qualified for use in space, and are particularly vulnerable to the effects of the space environment. As the demand for longer and more complex CubeSat missions increases, it is becoming more and more important to consider the effects of spacecraft charging in the design process. Results of surface charging analysis using Nascap-2k on a typical CubeSat design for a polar orbit scenario are illustrated. These results show that for a polar orbiting CubeSat, spacecraft charging could be an issue and steps should be taken to mitigate the effects for these small satellites.

  13. CloudSat Education Network: Partnerships for Outreach

    NASA Astrophysics Data System (ADS)

    TeBockhorst, D.

    2014-12-01

    CloudSat Education Network (CEN): Partnerships to improve the understanding of clouds in formal and informal settings. Since The CloudSat satellite launched in 2006 the Formal and Informal education programs for the mission have been focused on bringing an understanding about the mission science and the importance of clouds, climate & weather science. This has been done by creating and strengthening partnership and collaboration within scientific and educational communities around the country and the world. Because CloudSat was formally recognized as a Earth System Science Pathfinder campaign with the GLOBE program, the CEN developed a set of field protocols for student observations that augmented the GLOBE atmosphere protocols when there was a satellite overpass. This shared process between GLOBE & CloudSat resulted in the training & creation of CEN schools that are both GLOBE schools and CloudSat schools, and also produced three GLOBE partnerships that specialize in cloud science education and outreach. In addition, the CEN has developed productive relationships with other NASA missions and EPO teams. Specifically, in collaboration with the NASA CERES mission projects S'Cool and MyNASAData, we have co-presented at NSTA conferences and with schools participating in a NASA EPOESS-funded formal education project. This collaborative work has been a very real benefit to a wide variety of audiences needing to strengthen their understanding of clouds and their roles in the earth system, and we hope will serve as a model to future missions looking to involve the public in mission science.

  14. Improved Oceanographic Measurements with CryoSat SAR Altimetry

    NASA Astrophysics Data System (ADS)

    Cotton, David; Benveniste, Jérôme; Cipollini, Paolo; Andersen, Ole; Cancet, Mathilde; Ambrózio, Américo; Restano, Marco; Nilo Garcia, Pablo; Martin, Francisco

    2016-07-01

    The ESA CryoSat mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar "SAR" (or delay-Doppler) and interferometric SAR (SARin) modes. Studies on CryoSat data have analysed and confirmed the improved ocean measuring capability offered by SAR mode altimetry, through increased resolution and precision in sea surface height and wave height measurements, and have also added significantly to our understanding of the issues around the processing and interpretation of SAR altimeter echoes. We present work in four themes, building on work initiated in the CryoSat Plus for Oceans project (CP4O), each investigating different aspects of the opportunities offered by this new technology. The first two studies address the coastal zone, a critical region for providing a link between open-ocean and shelf sea measurements with those from coastal in-situ measurements, in particular tide gauges. Although much has been achieved in recent years through the Coastal Altimetry community, (http://www.coastalt.eu/community) there is a limit to the capabilities of pulse-limited altimetry, which often leaves an un-measured "white strip" right at the coastline. Firstly, a thorough analysis was made of the performance of "SAR" altimeter data (delay-Doppler processed) in the coastal zone. This quantified the performance, confirming the significant improvement over "conventional" pulse-limited altimetry. In the second study a processing scheme was developed with CryoSat SARin mode data to enable the retrieval of valid oceanographic measurements in coastal areas with complex topography. Thanks to further development of the algorithms, a new approach was achieved that can also be applied to SAR and conventional altimetry data (e.g., Sentinel-3, Jason series, Envisat). The third part of the project developed and evaluated improvements to the SAMOSA altimeter re-tracker that is implemented in the Sentinel-3 processing chain. The modifications to the

  15. The Revised SAT Score and Its Potential Benefits for the Admission of Minority Students to Higher Education

    ERIC Educational Resources Information Center

    Santelices, Maria Veronica; Wilson, Mark

    2015-01-01

    This paper investigates the predictive validity of the Revised SAT (R-SAT) score, proposed by Freedle (2003) as an alternative to compensate minority students for the potential harm caused by the relationship between item difficulty and ethnic DIF observed in the SAT. The R-SAT score is the score minority students would have received if only the…

  16. California and the SAT: A Reanalysis of University of California Admissions Data. Research & Occasional Paper Series: CSHE.8.04

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Brown, Terran; Sklar, Jeffrey C.

    2004-01-01

    As part of the University of California's recent reconsideration of the role of the SAT in admissions, the UC Office of the President published an extensive report, "UC and the SAT" (2001), which examined the value of SAT I Reasoning Test scores, SAT II Subject Test scores, and high school grades in predicting the grade-point averages of…

  17. Uncooled emissive infrared imagers for CubeSats

    NASA Astrophysics Data System (ADS)

    Puschell, Jeffery J.; Masini, Paolo

    2014-09-01

    Raytheon's fourth generation uncooled microbolometer array technology with digital output, High Definition (HD) 1920 × 1200 format and 12 μm cell size enables uncooled thermal infrared (TIR) multispectral imagers with the sensitivity and spatial sampling needed for a variety of Earth observation missions in LEO, GEO and HEO. A powerful combination of small detector cell size, fast optics and high sensitivity achieved without cryogenic cooling leads to instruments that are much smaller than current TIR systems, while still offering the capability to meet challenging measurement requirements for Earth observation missions. To consider how this technology could be implemented for Earth observation missions, we extend our previous studies with visible wavelength CubeSat imagers for environmental observations from LEO and examine whether small thermal infrared imagers based on fourth generation uncooled technology could be made small enough to fit onboard a 3U CubeSat and still meet challenging requirements for legacy missions. We found that moderate spatial resolution (~200 m) high sensitivity cloud and surface temperature observations meeting legacy MODIS/VIIRS requirements could be collected successfully with CubeSat-sized imagers but that multiple imagers are needed to cover the full swath for these missions. Higher spatial resolution land imagers are more challenging to fit into the CubeSat form factor, but it may be possible to do so for systems that require roughly 100 m spatial resolution. Regardless of whether it can fit into a CubeSat or not, uncooled land imagers meeting candidate TIR requirements can be implemented with a much smaller instrument than previous imagers. Even though this technology appears to be very promising, more work is needed to qualify this newly available uncooled infrared technology for use in space. If these new devices prove to be as space worthy as the first generation arrays that Raytheon qualified and built into the THEMIS imager

  18. Science Case for Planetary Exploration with Planetary CubeSats and SmallSats

    NASA Astrophysics Data System (ADS)

    Castillo-Rogez, Julie; Raymond, Carol; Jaumann, Ralf; Vane, Gregg; Baker, John

    2016-07-01

    Nano-spacecraft and especially CubeSats are emerging as viable low cost platforms for planetary exploration. Increasing miniaturization of instruments and processing performance enable smart and small packages capable of performing full investigations. While these platforms are limited in terms of payload and lifetime, their form factor and agility enable novel mission architectures and a refreshed relationship to risk. Leveraging a ride with a mothership to access far away destinations can significantly augment the mission science return at relatively low cost. Depending on resources, the mothership may carry several platforms and act as telecom relay for a distributed network or other forms of fractionated architectures. In Summer 2014 an international group of scientists, engineers, and technologists started a study to define investigations to be carried out by nano-spacecrafts. These applications flow down from key science priorities of interest across space agencies: understanding the origin and organization of the Solar system; characterization of planetary processes; assessment of the astrobiological significance of planetary bodies across the Solar system; and retirement of strategic knowledge gaps (SKGs) for Human exploration. This presentation will highlight applications that make the most of the novel architectures introduced by nano-spacecraft. Examples include the low cost reconnaissance of NEOs for science, planetary defense, resource assessment, and SKGs; in situ chemistry measurements (e.g., airless bodies and planetary atmospheres), geophysical network (e.g., magnetic field measurements), coordinated physical and chemical characterization of multiple icy satellites in a giant planet system; and scouting, i.e., risk assessment and site reconnaissance to prepare for close proximity observations of a mothership (e.g., prior to sampling). Acknowledgements: This study is sponsored by the International Academy of Astronautics (IAA). Part of this work is

  19. Max 2-SAT with up to 108 qubits

    NASA Astrophysics Data System (ADS)

    Santra, Siddhartha; Quiroz, Gregory; Ver Steeg, Greg; Lidar, Daniel A.

    2014-04-01

    We experimentally study the performance of a programmable quantum annealing processor, the D-Wave One (DW1) with up to 108 qubits, on maximum SAT problem with 2 variables per clause (MAX 2-SAT) problems. We consider ensembles of random problems characterized by a fixed clause density, an external parameter which we tune through its critical value in our experiments. We demonstrate that the DW1 is sensitive to the critical value of the clause density. The DW1 results are verified and compared with akmaxsat, an exact, state-of-the-art algorithm. We study the relative performance of the two solvers and how they correlate in terms of problem hardness. We find that the DW1 performance scales more favorably with problem size and that problem hardness correlation is essentially non-existent. We discuss the relevance and limitations of such a comparison.

  20. CloudSat Reflectivity Data Visualization Inside Hurricanes

    NASA Technical Reports Server (NTRS)

    Suzuki, Shigeru; Wright, John R.; Falcon, Pedro C.

    2011-01-01

    Animations and other outreach products have been created and released to the public quickly after the CloudSat spacecraft flew over hurricanes. The automated script scans through the CloudSat quicklook data to find significant atmospheric moisture content. Once such a region is found, data from multiple sources is combined to produce the data products and the animations. KMZ products are quickly generated from the quicklook data for viewing in Google Earth and other tools. Animations are also generated to show the atmospheric moisture data in context with the storm cloud imagery. Global images from GOES satellites are shown to give context. The visualization provides better understanding of the interior of the hurricane storm clouds, which is difficult to observe directly. The automated process creates the finished animation in the High Definition (HD) video format for quick release to the media and public.

  1. CloudSat Image of Tropical Thunderstorms Over Africa

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1

    CloudSat image of a horizontal cross-section of tropical clouds and thunderstorms over east Africa. The red colors are indicative of highly reflective particles such as water (rain) or ice crystals, which the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudS at Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The brown line below the image indicates the relative elevation of the land surface. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) visible image taken at nearly the same time.

  2. Level1B Performance Evaluation On CryoSat Products

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; Tagliani, Nicolas

    2013-12-01

    A performance assessment of the CryoSat products for SAR/SARin modes is here presented. The effective across-track IRF has been compared with the expected one, according to the system requirements, and exploiting the calibration products. Then, starting from the along-track processing for Delay/Doppler Radar altimeters, the theoretical model of the along-track IRF for CryoSat has been derived. Moreover the effects of the azimuth windowing on the along-track resolution and on the clutter suppression have been investigated. In particular, the clutter has been evaluated on the Level1b products for both sea ice and ocean scenario, revealing that the azimuth window allows to improve the signal to clutter ratio also in case of ocean waveforms.

  3. SeaHawk CubeSat system engineering

    NASA Astrophysics Data System (ADS)

    Schueler, Carl; Holmes, Alan

    2016-09-01

    The SeaHawk program is funded by the Gordon and Betty Moore Foundation of San Francisco, and managed by John Morrison of the University of North Carolina-Wilmington (UNC-W). Cloudland Instruments is developing SeaHawk's multispectral ocean color imager, known as HawkEye. HawkEye optics, filters, detector arrays, and electronics form a cube just 10 cm on a side to fit the SeaHawk 3U CubeSat manufactured by Clyde Space, Glasgow Scotland. This paper discusses the system engineering approach to design, develop, complete, test, integrate and launch two SeaHawk CubeSats in three years within a $1.7M budget.

  4. CarbonSat: ESA's Earth Explorer 8 Candidate Mission

    NASA Astrophysics Data System (ADS)

    Meijer, Y. J.; Ingmann, P.; Löscher, A.

    2012-04-01

    The CarbonSat candidate mission is part of ESA's Earth Explorer Programme. In 2010, two candidate opportunity missions had been selected for feasibility and preliminary definition studies. The missions, called FLEX and CarbonSat, are now in competition to become ESA's eighth Earth Explorer, both addressing key climate and environmental change issues. In this presentation we will provide a mission overview of CarbonSat with a focus on science. CarbonSat's primary mission objective is the quantification and monitoring of CO2 and CH4 sources and sinks from the local to the regional scale for i) a better understanding of the processes that control carbon cycle dynamics and ii) an independent estimate of local greenhouse gas emissions (fossil fuel, geological CO2 and CH4, etc.) in the context of international treaties. A second priority objective is the monitoring/derivation of CO2 and CH4 fluxes on regional to global scale. These objectives will be achieved by a unique combination of frequent, high spatial resolution (2 x 2 km2) observations of XCO2 and XCH4 coupled to inverse modelling schemes. The required random error of a single measurement at ground-pixel resolution is of the order of between 1 and 3 ppm for XCO2 and between 9 and 17 ppb for XCH4. High spatial resolution is essential in order to maximize the probability for clear-sky observations and to identify flux hot spots. Ideally, CarbonSat shall have a wide swath allowing a 6-day global repeat cycle. The CarbonSat observations will enable CO2 emissions from coal-fired power plants, localized industrial complexes, cities, and other large emitters to be objectively assessed at a global scale. Similarly, the monitoring of natural gas pipelines and compressor station leakage will become feasible. The detection and quantification of the substantial geological greenhouse gas emission sources such as seeps, volcanoes and mud volcanoes will be achieved for the first time. CarbonSat's Greenhouse Gas instrument will

  5. Rotary Percussive Sample Acquisition Tool (SAT): Hardware Development and Testing

    NASA Technical Reports Server (NTRS)

    Klein, Kerry; Badescu, Mircea; Haddad, Nicolas; Shiraishi, Lori; Walkemeyer, Phillip

    2012-01-01

    In support of a potential Mars Sample Return (MSR) mission an Integrated Mars Sample Acquisition and Handling (IMSAH) architecture has been proposed to provide a means for Rover-based end-to-end sample capture and caching. A key enabling feature of the architecture is the use of a low mass sample Acquisition Tool (SAT) that is capable of drilling and capturing rock cores directly within a sample tube in order to maintain sample integrity and prevent contamination across the sample chain. As such, this paper will describe the development and testing of a low mass rotary percussive SAT that has been shown to provide a means for core generation, fracture, and capture.

  6. The Relationship between SAT Scores and Retention to the Second Year: Replication with 2009 SAT Validity Sample. Statistical Report 2011-3

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Patterson, Brian F.

    2012-01-01

    The College Board formed a research consortium with four-year colleges and universities to build a national higher education database with the primary goal of validating the revised SAT for use in college admission. A study by Mattern and Patterson (2009) examined the relationship between SAT scores and retention to the second year of college. The…

  7. Dellingr- A Path to Compelling Science with CubeSats

    NASA Astrophysics Data System (ADS)

    Johnson, M.; Bonalsky, T.; Chornay, D.; Clagett, C.; Cudmore, A.; Ericsson, A.; Hesh, S.; Jones, S.; Kepko, L.; Rodriguez, J.; Sittler, E.; Starin, S.; Santos, L.; Sheikh, S.; Uribe, P.; Zesta, E.

    2015-10-01

    Advancements in the capabilities of miniaturized systems are dramatically increasing interest in achieving science from CubeSats. The Dellingr project targets this interest. It will realize compelling science from a 6U spacecraft while developing human and spacecraft systems required to cost-efficiently deliver small satellites capable of reliably achieving mission objectives in divers environments—from low earth orbit to challenging radiation and thermal environments associated with lunar and planetary missions.

  8. Onboard autonomy on the Three Corner Sat mission

    NASA Technical Reports Server (NTRS)

    Chien, S. A.; Sherwood, R.

    2002-01-01

    In 2003, the student-built three satellite constellation Three Corner Sat (3CS) Mission will demonstrate onboard autonomy including: science data validation and prioritization, mission re-planning, and robust execution. Future observations will be planned onboard based on the quality of aquired science, available memory and power, and anticipated downlinks. These capabilities will allow 3CS to aquire additional science data if resources are available and to return only the highest quality science data.

  9. Maker of SAT Aims New Test at 8th Graders

    ERIC Educational Resources Information Center

    Cech, Scott J.

    2008-01-01

    Officials at the New York City-based College Board last week rolled out their newest product: ReadiStep. No, it is not a new piece of exercise equipment or a whipped dessert topping--it is a test for 8th graders that some critics are calling a pre-PSAT, referring to the Preliminary SAT assessment taken by 9th and 10th graders and owned by the…

  10. WindSat On-Orbit Warm Load Calibration

    DTIC Science & Technology

    2006-03-01

    scheme was selected to solve the finite difference equations derived from the thermal network . This numerical scheme averaged the temperature derivatives...WindSat. I. INTRODUCTION WINDSAT is a satellite- based multifrequency polari-metric microwave radiometer developed by the Naval Research Laboratory for the...every 1.89 s) by using a two-point calibration method based on the heritage design of other spaceborne imaging radiometer systems such as the Special

  11. SAT Performance: Understanding the Contributions of Cognitive/Learning and Social/Personality Factors

    PubMed Central

    HANNON, BRENDA; MCNAUGHTON-CASSILL, MARY

    2011-01-01

    SUMMARY This study identifies a number of sources of individual differences in SAT performance by examining the simultaneous contributions of factors from two otherwise disparate research areas, namely cognition/learning and social/personality. Preliminary analysis revealed that just the cognitive/learning measures accounted for 37.8, 41.4 and 21.9% of the variance in SAT, V-SAT and Q-SAT performance, respectively while just the social/personality measures accounted for 21.4, 18.2 and 17.3% of the variance. When combined, cognitive/learning and social/personality factors accounted for even larger amounts of variance in performance; specifically 43.4, 44.6 and 28% for the SAT, V-SAT and Q-SAT, respectively. Finally, the results revealed that three measures consistently predicted performance on the SAT, V-SAT and Q-SAT; two measures were the learning/cognitive factors of working memory and integration of new text-based information with information from long-term memory and one measure was the social/personality factor, test anxiety. PMID:21804694

  12. Data quality assessment of CryoSat products

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Bouzinac, Catherine; Fornari, Marco; Mannan, Rubinder

    2013-04-01

    The main payload of CryoSat is a Ku band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach a significantly improved along track resolution with respect to traditional pulse-width limited altimeters. There are three operating modes: low resolution mode (LRM), Synthetic Aperture Radar (SAR) and Synthetic Aperture Radar Interferometric (SARIn). Both the Level 1b and the Level 2 data products are defined depending on the operating mode used by the instrument. However, Level 1b products essentially contain an average echo for each location along the ground track while Level 2 products contains an elevation for each location along the satellite track. In this poster we will detail as first the different data products and then the quality achieved on those products will be described after more than 2 years of operational activity of the CryoSat satellite. In particular, the characteristics of the impulse response function in the two direction, the along track and the across track, will be described in order to verify that the performance are in line with expectation as well as stable over the time. To exploit the stability over the 2 years of mission, the products obtained as outcomes of the reprocessing activity will be exploited, allowing to manage an homogeneous set of data processed with the latest version of the CryoSat IPF.

  13. iSat Surface Charging and Thruster Plume Interactions Analysis

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Willis, E. M.; Minow, J. I.

    2016-01-01

    Characterizing the electromagnetic interaction of a satellite in low Earth, high inclination orbit with the space plasma environment and identifying viable charging mitigation strategies is a critical mission design task. High inclination orbits expose the vehicle to auroral charging environments that can potentially charge surfaces to kilovolt potentials and electric thruster propulsion systems will interact with the ambient plasma environment throughout the orbit. NASA is designing the Iodine Satellite (iSAT) cubesat mission to demonstrate operations of an iodine electric thruster system. The spacecraft will be deployed as a secondary payload from a launch vehicle which has not yet been identified so the program must plan for the worst case environments over a range of orbital inclinations. We will first present results from a NASA and Air Force Charging Analyzer Program (Nascap) -2k surface charging calculation used to evaluate the effects of auroral charging on the spacecraft and to provide the charging levels at other locations in orbit for a thruster plume interaction analysis for the iSAT mission. We will then discuss results from the thruster interactions analysis using the Electric Propulsion Interactions Code (EPIC) with inputs from Nascap-2k. The results of these analyses are being used by the iSAT program to better understand how their spacecraft will interact with the space plasma environment in the range of environments that could be encountered when the final mission orbit is selected.

  14. Evaluation of the Impact of an Additive Manufacturing Enhanced CubeSat Architecture on the CubeSat Development Process

    DTIC Science & Technology

    2016-09-15

    Orbital Deployer (P-POD), and there are a number of other CubeSat interfaces available today (Swartwout, 2013). The standardized launch interface was...schedule, lifetime and reliability, total delta V (or the measure of impulse necessary to 11 perform a maneuver in m/s), orbit , and payload...subsystem is provide thrust to change the spacecraft’s orbit and dump momentum as needed (Wertz et al., 2011). The ADACS and TNC subsystems comprise the

  15. Arctic and Antarctic Sea-Ice Freeboard and Thickness Retrievals from CryoSat-2 and EnviSat

    NASA Astrophysics Data System (ADS)

    Ricker, Robert; Hendricks, Stefan; Schwegmann, Sandra; Helm, Veit; Rinne, Eero

    2016-04-01

    The CryoSat-2 satellite is now in the 6th year of data acquisition. With its synthetic aperture radar altimeter, CryoSat-2 achieves great improvements in the along track resolution compared to previous radar altimeter missions like ERS or Envisat. The latitudinal coverage contains major parts of the Arctic marine ice fields where previous missions left a big data gap around the North Pole and especially over the multiyear ice zone north of Greenland. With this unique data set, changes in sea-ice thickness can be investigated in the context of the rapid reduction of the Arctic sea-ice cover which has been observed during the last decades. We present the current state of the CryoSat-2 Arctic sea-ice thickness retrieval that is processed at the Alfred Wegener Institute and available via seaiceportal.de (originally: meereisportal.de). Though biases in sea-ice thickness may occur due to the interpretation of waveforms, airborne and ground-based validation measurements give confidence that the retrieval algorithm enables us to capture the actual distributions of sea-ice regimes. Nevertheless, long time series of data retrievals are essential to estimate trends in sea-ice thickness and volume. Today, more than 20 years of radar altimeter data are potentially available and capable to derive sea ice thickness. However, data originate from satellites with different sensor characteristics. Therefore, it is crucial to study the consistency between single sensors to derive long and consistent time series. We present results from the tested consistency between Antarctic freeboard measurements of the radar altimeters on-board of Envisat and CryoSat-2 for their overlap period in 2011.

  16. Pseudo LRM waveforms from CryoSat SARin acquisition

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso; Féménias, Pierre

    2016-04-01

    CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. The main payload of CryoSat is a Ku-band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. When SIRAL operates in SAR or SARin mode, the obtained waveforms have an along-track resolution and a speckle reduction which is increased with respect to the pulse-limited waveforms. Anyway, in order to analyze the continuity of the geophysical retrieved parameters among different acquisition modes, techniques to transform SARin mode data to pseudo-LRM mode data are welcome. The transformation process is known as SAR reduction and it is worth recalling here that only approximate pseudo-LRM waveforms can be obtained in case of closed burst acquisitions, as SIRAL operates. A SAR reduction processing scheme has been developed to obtain pseudo-LRM waveforms from CryoSat SARin acquisition. As a trade-off between the along-track length on Earth surface contributing to one SARin pseudo-LRM waveform and the noisiness of the waveform itself, it has been chosen a SAR reduction approach based on the averaging of all the SARin echoes received each 20Hz, resulting in one pseudo-LRM waveform for each SARin burst given the SARin burst repetition period. SARin pseudo-LRM waveforms have been produced for CryoSat acquisition both on ice and sea surfaces, aiming at verifying the continuity of the retracked surface height over the ellipsoid between genuine LRM products and pseudo-LRM products. Moreover, the retracked height from the SARin pseudo-LRM has been

  17. Florida Tech CubeSat Experiment Feasibility Study

    NASA Technical Reports Server (NTRS)

    Arrasmith, William W.; Bucaille, Stephane; Rusovici, Razvan; Platt, Don; Guidry, Todd; Bandar, Deepika; Coots, Everett; Davidson, Russ

    2010-01-01

    CubeSats are a relatively new type of satellite. Smaller than long-term (5+ year life expectancy) satellites, these pico-satellites are comparatively cheap, small (10x10x10 cm), and are very versatile. Universities world-wide are using CubeSats to conduct a variety of experiments in space without the need for a large experimental platform. Today CubeSats are considered to be one of the most effective ways to send a small payload into space and has attracted the attention of many educational and non-profit organizations. As this pico-satellite model continues to gain penetration into the satellite build and launch industry, it is expected that more governmental, educational, and commercial interests will emerge. As an example, more of the space-related items of high interest to the National Science Foundation may be tackled with a CubeSat platform resulting in lower life cycle costs than traditional satellite options. NASA LSP, in cooperation with the Florida Institute of Technology, has initiated a feasibility study to investigate the technical aspects of measuring and transferring vibration, acceleration, temperature, and video data from a CubeSat to NASA Hanger AE on Cape Canaveral Air Force Station (CCAFS) a.k.a. Kennedy Space Center (KSC). This report provides a technical feasibility analysis to determine whether-or-not a specific set of NASA/LSP requirements can be accomplished. Our approach has been to provide a "notional" component layout to determine the feasibility of the NASA/LSP stakeholder requirements. The notional layout is used to consider component level technical issues such as size, weight, & power (SWaP), bandwidth, and other critical technical parameters. Even though the notional components may satisfy the stated requirements and thereby demonstrate feasibility, the notional layout is NOT considered a design since no component optimization and design trade-off analysis has taken place. This activity should be accomplished in an appropriate

  18. A review of planetary and space science projects presented at iCubeSat, the Interplanetary CubeSat Workshop

    NASA Astrophysics Data System (ADS)

    Johnson, Michael

    2015-04-01

    iCubeSat, the Interplanetary CubeSat Workshop, is an annual technical workshop for researchers working on an exciting new standardised platform and opportunity for planetary and space scientists. The first workshop was held in 2012 at MIT, 2013 at Cornell, 2014 at Caltech with the 2015 workshop scheduled to take place on the 26-27th May 2015 at Imperial College London. Mission concepts and flight projects presented since 2012 have included orbiters and landers targeting asteroids, the moon, Mars, Venus, Saturn and their satellites to perform science traditionally reserved for flagship missions at a fraction of their cost. Some of the first missions proposed are currently being readied for flight in Europe, taking advantage of multiple ride share launch opportunities and technology providers. A review of these and other interplanetary CubeSat projects will be presented, covering details of their science objectives, instrument capabilities, technology, team composition, budget, funding sources, and the other programattic elements required to implement this potentially revolutionary new class of mission.

  19. Achieving Science Goals with CubeSats: a Study by the National Academies

    NASA Astrophysics Data System (ADS)

    Zurbuchen, T.; Sheffer, A.

    2015-12-01

    We will discuss an ongoing study by the National Academies' Space Studies Board focused on CubeSats, and in particular their scientific potential and technological promise. Through this study, several US agencies seek inputs on the current status of CubeSat programs in government, academic and industrial sectors. The study will also make recommendations about additional investments that are needed to further increase the value of CubeSats to the science community. Furthermore, the committee will provide sample priority science goals that describe near-term opportunities, such as providing continuity of key measurements to mitigate potential gaps in measurements of key parameters- and that can be accomplished given the current state of CubeSat capabilities. We will summarize some data in the public domain about CubeSats our study is based on, and also focus on some selected science opportunities that can be addressed by CubeSats and which are part of Decadal Survey priorities.

  20. Proton transport in triflic acid hydrates studied via path integral car-parrinello molecular dynamics.

    PubMed

    Hayes, Robin L; Paddison, Stephen J; Tuckerman, Mark E

    2009-12-31

    The mono-, di-, and tetrahydrates of trifluoromethanesulfonic acid, which contain characteristic H(3)O(+), H(5)O(2)(+), and H(9)O(4)(+) structures, provide model systems for understanding proton transport in materials with high perfluorosulfonic acid density such as perfluorosulfonic acid membranes commonly employed in hydrogen fuel cells. Ab initio molecular dynamics simulations indicate that protons in these solids are predisposed to transfer to the water most strongly bound to sulfonate groups via a Grotthuss-type mechanism, but quickly return to the most solvated defect structure either due to the lack of a nearby species to stabilize the new defect or a preference for the proton to be maximally hydrated. Path integral molecular dynamics of the mono- and dihydrate reveal significant quantum effects that facilitate proton transfer to the "presolvated" water or SO(3)(-) in the first solvation shell and increase the Zundel character of all the defects. These trends are quantified in free energy profiles for each bonding environment. Hydrogen bonding criteria for HOH-OH(2) and HOH-O(3)S are extracted from the two-dimensional potential of mean force. The quantum radial distribution function, radius of gyration, and root-mean-square displacement position correlation function show that the protonic charge is distributed over two or more water molecules. Metastable structural defects with one excess proton shared between two sulfonate groups and another Zundel or Eigen type cation defect are found for the mono- and dihydrate but not for the tetrahydrate crystal. Results for the tetrahydrate native crystal exhibit minor differences at 210 and 250 K. IR spectra are calculated for all native and stable defect structures. Graph theory techniques are used to characterize the chain lengths and ring sizes in the hydrogen bond network. Low conductivities when limited water is present may be attributable to trapping of protons between SO(3)(-) groups and the increased

  1. From CryoSat-2 to Sentinel-3 and Beyond

    NASA Astrophysics Data System (ADS)

    Francis, R.

    2011-12-01

    CryoSat-2 carried into Earth orbit the first altimeter using SAR principles, although similar techniques had been used on earlier Venusian missions. Furthermore, it carries a second antenna and receive chain, and has been very carefully calibrated, allowing interferometry between these antennas. The results of the SAR mode and of the interferometer have met all expectations, with handsome margins. Even before the launch of CryoSat-2 the further development of this concept was underway with the radar for the oceanography mission Sentinel-3. While this radar, named SRAL (SAR Radar Altimeter) does not have the interferometer capability of CryoSat-2's SIRAL (SAR Interferometric Radar Altimeter), it does have a second frequency, to enable direct measurement of the delay induced by the ionospheric electron content. Sentinel-3 will have a sun-synchronous orbit, like ERS and EnviSat, and will have a similar latitudinal range: about 82° north and south, compared to CryoSat's 88°. Sentinel-3 will operate its radar altimeter in the high-resolution SAR mode over coastal oceans and inland water, and will revert to the more classical pulse-width limited mode over the open oceans. The SAR mode generates data at a high rate, so the major limiting factor is the amount of on-board storage. The power consumption is also higher, imposing less critical constraints. For sizing purposes the coastal oceans are defined as waters within 300 km of the continental shorelines. Sentinel-3 is expected to be launched in 2013 and be followed 18 months later by a second satellite of the same design. The next step in the development of this family of radar altimeters is Jason-CS, which will provide Continuity of Service to the existing Jason series of operational oceanography missions. Jason-CS has a very strong heritage from CryoSat but will fly the traditional Jason orbit, which covers latitudes up to 66° from a high altitude of 1330 km. The new radar is called Poseidon-4, to emphasise the

  2. Thermal Analysis of Iodine Satellite (iSAT)

    NASA Technical Reports Server (NTRS)

    Mauro, Stephanie

    2015-01-01

    This paper presents the progress of the thermal analysis and design of the Iodine Satellite (iSAT). The purpose of the iSAT spacecraft (SC) is to demonstrate the ability of the iodine Hall Thruster propulsion system throughout a one year mission in an effort to mature the system for use on future satellites. The benefit of this propulsion system is that it uses a propellant, iodine, that is easy to store and provides a high thrust-to-mass ratio. The spacecraft will also act as a bus for an earth observation payload, the Long Wave Infrared (LWIR) Camera. Four phases of the mission, determined to either be critical to achieving requirements or phases of thermal concern, are modeled. The phases are the Right Ascension of the Ascending Node (RAAN) Change, Altitude Reduction, De-Orbit, and Science Phases. Each phase was modeled in a worst case hot environment and the coldest phase, the Science Phase, was also modeled in a worst case cold environment. The thermal environments of the spacecraft are especially important to model because iSAT has a very high power density. The satellite is the size of a 12 unit cubesat, and dissipates slightly more than 75 Watts of power as heat at times. The maximum temperatures for several components are above their maximum operational limit for one or more cases. The analysis done for the first Design and Analysis Cycle (DAC1) showed that many components were above or within 5 degrees Centigrade of their maximum operation limit. The battery is a component of concern because although it is not over its operational temperature limit, efficiency greatly decreases if it operates at the currently predicted temperatures. In the second Design and Analysis Cycle (DAC2), many steps were taken to mitigate the overheating of components, including isolating several high temperature components, removal of components, and rearrangement of systems. These changes have greatly increased the thermal margin available.

  3. CryoSat data quality assessment and product evolutions

    NASA Astrophysics Data System (ADS)

    Bouffard, Jerome; Femenias, Pierre; Parrinello, Tommaso; Fornari, Marco; Brockley, David; Scagliola, Michele; Calafat, Francisco; Roca, Monica

    2015-04-01

    The main payload of the ESA Earth Explorer CryoSat satellite is a Ku band pulse-width limited radar altimeter, operating in 3 different modes function of a mask of geographical zones. Over the ocean and ice sheet interiors, CryoSat mainly operates like a conventional pulse-limited radar altimeter whereas over sea ice, coherently transmitted echoes are combined in order to carry out measurements at a higher resolution. Around ice sheet margins, a 2nd antenna is used as an interferometer in order to determine the across-track angle to the earliest radar returns. Two kinds of data are distributed to the scientific user community and are quality controlled and validated by ESA/ESRIN SPPA office with the support of an industrial consortium: the Level 1b products essentially contain average echoes collected along the ground track while the Level 2 products contain elevations and associated geophysical parameters retrieved from these echoes. In this poster we first briefly present the characteristics of Level 1b and Level 2 CryoSat products over ocean, land ice and sea ice in addition to the results of recent quality control activities. Due to anomalies detected in previous data release and the need of continuously improving the data quality, ESA and its industrial partners has implemented a new version of the processors by the early of 2015, followed by a full reprocessing campaign. The main evolutions of this so called "Baseline C", the validation of the associated Test Data Set and the main improvements expected from this new release are also presented.

  4. CubeSat Remote Sensing: A Survey of Current Capabilities

    NASA Astrophysics Data System (ADS)

    Hegel, D.

    2014-12-01

    Recent years have seen dramatic growth in the availability and capability of very small satellites for atmospheric sensing, and other space-based science, as the simplicity of integration and low cost of these platforms enables projects that would otherwise be prohibitively expensive, or demand excessive expertise/infrastructure to execute. This paper surveys the current state-of-the-art for CubeSat performance, including pointing accuracy, geolocation, available power, and data downlink capacity. Applications for up-coming missions, such as CeREs, MinXSS, and HARP will also be discussed.

  5. EXACT - The Solar X-Ray Spectrometer CubeSat

    NASA Astrophysics Data System (ADS)

    Knuth, Trevor; Glesener, Lindsay; Gebre-Egziabher, Demoz; Vogt, Ryan; Denis, Charles; Weiher, Hannah; Runnels, Joel; Vievering, Juliana

    2016-05-01

    The Experiment for X-ray Characterization and Timing (EXACT) mission will be a CubeSat based hard X-ray spectrometer used for viewing solar flares with high time precision. Solar flares and the related coronal mass ejections affect space weather and the near-Earth environment. EXACT can study the hard X-rays generated by the Sun in the declining phase of Solar Cycle 24 in order to probe electron acceleration in solar eruptive events while also serving as a precursor to future hard X-ray spectrometers that could monitor the Sun continuously.

  6. Preliminary thermal design of the COLD-SAT spacecraft

    NASA Technical Reports Server (NTRS)

    Arif, Hugh

    1991-01-01

    The COLD-SAT free-flying spacecraft was to perform experiments with LH2 in the cryogenic fluid management technologies of storage, supply and transfer in reduced gravity. The Phase A preliminary design of the Thermal Control Subsystem (TCS) for the spacecraft exterior and interior surfaces and components of the bus subsystems is described. The TCS was composed of passive elements which were augmented with heaters. Trade studies to minimize the parasitic heat leakage into the cryogen storage tanks are described. Selection procedure for the thermally optimum on-orbit spacecraft attitude was defined. TRASYS-2 and SINDA'85 verification analysis was performed on the design and the results are presented.

  7. Solving Open Job-Shop Scheduling Problems by SAT Encoding

    NASA Astrophysics Data System (ADS)

    Koshimura, Miyuki; Nabeshima, Hidetomo; Fujita, Hiroshi; Hasegawa, Ryuzo

    This paper tries to solve open Job-Shop Scheduling Problems (JSSP) by translating them into Boolean Satisfiability Testing Problems (SAT). The encoding method is essentially the same as the one proposed by Crawford and Baker. The open problems are ABZ8, ABZ9, YN1, YN2, YN3, and YN4. We proved that the best known upper bounds 678 of ABZ9 and 884 of YN1 are indeed optimal. We also improved the upper bound of YN2 and lower bounds of ABZ8, YN2, YN3 and YN4.

  8. FalconSAT-7: A Photon Sieve Solar Telescope

    DTIC Science & Technology

    2011-09-01

    technology has only incrementally improved in areal mass since the beginning of space -based imagery. For example, the Hubble Space Telescope has a mirror... space -based photon sieve telescope from a CubeSat platform. Fig. 1: Solid Works picture of Peregrine, a 0.2m photon sieve deployed from a 3U...with 180 kg/m2 while the James Webb Space Telescope has reduced this to just 25 kg/m2 over a quarter of a century later. Not only is size an issue

  9. NittanySat Final Report for University Nanosatellite-5 Program

    DTIC Science & Technology

    2009-10-12

    NittanySat requires only one probe and the supporting circuitry for this probe. The LP experiment was developed for a M.S. thesis ( Escobar , 2009), and... Escobar , Sven G. Bilén, Robert M. Capuro 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING...team has completed the Flight Competition Review (FCR), which marks the culmination of the 2-year development of a prototype of a nanosatellite as

  10. Tunable Microwave Component Technologies for SatCom-Platforms

    NASA Astrophysics Data System (ADS)

    Maune, Holger; Jost, Matthias; Wiens, Alex; Weickhmann, Christian; Reese, Roland; Nikfalazar, Mohammad; Schuster, Christian; Franke, Tobias; Hu, Wenjuan; Nickel, Matthias; Kienemund, Daniel; Prasetiadi, Ananto Eka; Jakoby, Rolf

    2017-03-01

    Modern communication platforms require a huge amount of switched RF component banks especially made of different filters and antennas to cover all operating frequencies and bandwidth for the targeted services and application scenarios. In contrast, reconfigurable devices made of tunable components lead to a considerable reduction in complexity, size, weight, power consumption, and cost. This paper gives an overview of suitable technologies for tunable microwave components especially for SatCom applications. Special attention is given to tunable components based on functional materials such as barium strontium titanate (BST) and liquid crystal (LC).

  11. Concepts for an Enhanced CubeSat GEO Space Situational Awareness Architecture

    NASA Astrophysics Data System (ADS)

    Morris, K.; Rice, C.

    2014-09-01

    With space becoming more congested, competitive, and contested, new space situational awareness architectures are required to maintain the US advantage in space. This, along with government budget concerns, requires new and potentially radical approaches for performing Space Situational Awareness (SSA). Previous studies have shown that CubeSats can fill holes in the GEO SSA architecture and provide point of light observations of objects. The next logical step is to develop a CubeSat constellation that provides complete coverage of the GEO belt while minimizing the cost to field the architecture. CubeSats provide value to the GEO SSA mission by hosting optical systems and taking pictures along the GEO belt, however, CubeSats do have limitations when it comes to mission assurance. Because of this, mission orbits must be chosen such that failed CubeSats do not become pieces of debris. In addition, recent advances in CubeSat propulsion systems open up new orbits and constellations due to the increased thrust and Delta V. Analyzing the CubeSat capabilities along with launch rideshare options determined the most cost effective architecture to provide high accuracy tracks to all objects at GEO with minimal gaps between observations. Several mission orbits are combined to provide the access and coverage required. The few launches direct to GEO can accommodate CubeSats that can be place in a GEO +500 km orbit. The CubeSats would image the GEO belt as they drift with respect to GEO performing the track and custody missions. More launches occur to the GEO transfer orbit during the and CubeSats ridesharing on these launches reside in an elliptical orbit with the apogee at GEO and the CubeSat propulsion system can be used to raise perigee to maintain a reasonable mission life. CubeSats in this orbit can image the GEO belt near apogee from different angles than the +500 km orbits that contributes to higher accuracy tracks. Finally, ridesharing as hosted payloads on commercial

  12. Epigenetic regulation of spermidine/spermine N1-acetyltransferase (SAT1) in suicide.

    PubMed

    Fiori, Laura M; Turecki, Gustavo

    2011-09-01

    We have recently shown that the expression of spermidine/spermine N1-acetyltransferase (SAT1) is downregulated across the brains of suicide completers, and that its expression is influenced by genetic variations in the promoter. Several promoter polymorphisms in SAT1, including rs6526342, have been associated with suicide and other psychiatric disorders, and display haplotype-specific effects on expression. However, these effects cannot explain total variability in SAT1 expression, and other regulatory mechanisms, such as epigenetic factors, may also be at play. In this study, we assessed the involvement of epigenetic factors in controlling SAT1 expression in the prefrontal cortex of suicide completers by mapping CpG methylation across a 1880-bp region of the SAT1 promoter, and measuring levels of tri-methylated histone-3-lysine 27 (H3K27me3) at the promoter in suicide completers and controls. Our results demonstrated that CpG methylation was significantly negatively correlated with SAT1 expression. Although overall or site-specific CpG methylation was not associated with suicide or SAT1 expression, we observed high levels of methylation at the polymorphic CpG site created by rs6526342, indicating a relationship between promoter haplotypes and methylation. There was no association between H3K27me3 and suicide, nor was this modification associated with SAT1 expression. Overall, our results indicate that epigenetic factors in the promoter region of SAT1 influence gene expression levels, and may provide a mechanism for both our previous findings of haplotype-specific effects of promoter variations on SAT1 expression, as well as the widespread downregulation of SAT1 expression observed in the brains of suicide completers.

  13. The promise of scientific CubeSat missions

    NASA Astrophysics Data System (ADS)

    Moretto Jorgensen, Therese

    In 2008, The US National Science Foundation (NSF) started a program in support of CubeSat-based science missions for space weather and atmospheric research. This program implements a new and very different approach to providing needed scientific space measurements. It builds on recent engineering and system developments of CubeSat technology that have established the technical feasibility of tiny spacecraft missions that can be launched as secondary payloads at very low cost and rapid time scales as they pose virtually no risk to the launch vehicle or its primary payload. This makes space measurements achievable within the scope of the traditional NSF grants programs and greatly enhances the participation of the larger university community in space activities. Equally importantly, such projects offer unique opportunities for hands-on education and training for students and young professionals in aerospace engineering and experimental space science. Currently, the program supports 6 projects, the first one of which is scheduled for launch in May 2010. The presentation will describe the creation of the program, current projects, and future plans and will discuss successes and challenges encountered so far.

  14. COLD-SAT: A technology satellite for cryogenic experimentation

    NASA Technical Reports Server (NTRS)

    Arif, H.; Kroeger, E. W.

    1989-01-01

    NASA-Lewis (LeRC) is involved in the development and validation of analytical models which describe the fluid dynamic and thermodynamic processes associated with the storage, acquisition and transfer of subcritical cryogenic fluids in low gravity. Four concurrent studies, including one in-house at LeRC, are underway to determine the feasibility of performing model validation experiments aboard a free-flying spacecraft (S/C) called Cryogenic On-Orbit Liquid Depot-Storage, Acquisition and Transfer (COLD-SAT), using liquid hydrogen as the cryogen. The technology requirements for the experiments are described along with the initial LeRC concepts for the S/C and an experiment subsystem comprising of cryogenic tankage (a supply dewar and three receiver tanks), gas pressurization bottles (both helium and autogenous hydrogen), their associated plumbing, and instrumentation for data collection. Experiments were categorized into enabling/high priority Class 1 technologies and component/system Class 2 demonstrations. As initially envisioned by LeRC, COLD-SAT would have had a 1997 launch aboard a Delta-2 for a 6 month active lifetime in a 925 km orbit with a pseudo-inertial attitude.

  15. COLD-SAT: An orbital cryogenic hydrogen technology experiment

    NASA Technical Reports Server (NTRS)

    Schuster, J. R.; Wachter, Joseph P.; Powers, Albert G.

    1989-01-01

    The COLD-SAT spacecraft will perform subcritical liquid hydrogen storage and transfer experiments under low-gravity conditions to provide engineering data for future space transportation missions. Consisting of an experiment module mated to a spacecraft bus, COLD-SAT will be placed in an initial 460 km circular orbit by an Atlas I commercial launch vehicle. After deployment, the three-axis-controlled spacecraft bus will provide electric power, experiment control and data management, communications, and attitude control along with propulsive acceleration levels ranging from 10(-6) to 10(-4)g. These accelerations are an important aspect of some of the experiments, as it is desired to know the effects that low gravity levels might have on the heat and mass transfer processes involved. The experiment module will contain the three liquid hydrogen tanks, valves, pressurization equipment, and instrumentation. At launch all the hydrogen will be in the largest tank, which has helium-purged MLI and is loaded and topped off by the hydrogen tanking system used for the Centaur upper stage of the Atlas. The two smaller tanks will be utilized in orbit for performing some of the experiments. The experiments are grouped into two classes on the basis of their priority, and include six regarded as enabling technology and nine regarded as enhancing technology.

  16. The COLD-SAT Experiment for Cryogenic Fluid Management Technology

    NASA Technical Reports Server (NTRS)

    Schuster, J. R.; Wachter, J. P.; Vento, D. M.

    1990-01-01

    Future national space transportation missions will depend on the use of cryogenic fluid management technology development needs for these missions. In-space testing will be conducted in order to show low gravity cryogenic fluid management concepts and to acquire a technical data base. Liquid H2 is the preferred test fluid due to its propellant use. The design of COLD-SAT (Cryogenic On-orbit Liquid Depot Storage, Acquisition, and Transfer Satellite), an Expendable Launch Vehicle (ELV) launched orbital spacecraft that will perform subcritical liquid H2 storage and transfer experiments under low gravity conditions is studied. An Atlas launch vehicle will place COLD-SAT into a circular orbit, and the 3-axis controlled spacecraft bus will provide electric power, experiment control, and data management, attitude control, and propulsive accelerations for the experiments. Low levels of acceleration will provide data on the effects that low gravity might have on the heat and mass transfer processes used. The experiment module will contain 3 liquid H2 tanks; fluid transfer, pressurization and venting equipment; and instrumentation.

  17. South Atlantic anomaly and CubeSat design considerations

    NASA Astrophysics Data System (ADS)

    Fennelly, Judy A.; Johnston, William R.; Ober, Daniel M.; Wilson, Gordon R.; O'Brien, T. Paul; Huston, Stuart L.

    2015-09-01

    Effects of the South Atlantic Anomaly (SAA) on spacecraft in low Earth orbit (LEO) are well known and documented. The SAA exposes spacecraft in LEO to high dose of ionizing radiation as well as higher than normal rates of Single Event Upsets (SEU) and Single Event Latch-ups (SEL). CubeSats, spacecraft built around 10 x 10 x 10 cm cubes, are even more susceptible to SEUs and SELs due to the use of commercial off-the-shelf components for electronics and payload instrumentation. Examination of the SAA using both data from the Defense Meteorological Satellite Program (DMSP) and a new set of models for the flux of particles is presented. The models, AE9, AP9, and SPM for energetic electrons, energetic protons and space plasma, were developed for use in space system design. These models introduce databased statistical constraints on the uncertainties from measurements and climatological variability. Discussion of the models' capabilities and limitations with regard to LEO CubeSat design is presented.

  18. COLD-SAT - An orbital cryogenic hydrogen technology experiment

    NASA Technical Reports Server (NTRS)

    Schuster, J. R.; Wachter, Joseph P.; Powers, Albert G.

    1989-01-01

    The COLD-SAT spacecraft will perform subcritical liquid hydrogen storage and transfer experiments under low-gravity conditions to provide engineering data for future space transportation missions. Consisting of an experiment module mated to a spacecraft bus, COLD-SAT will be placed in an initial 460 km circular orbit by an Atlas I commercial launch vehicle. After deployment, the three-axis-controlled spacecraft bus will provide electric power, experiment control and data management, communications, and attitude control along with propulsive acceleration levels ranging from 10 (-6) to 10(-4) g. These accelerations are an important aspect of some of the experiments, as it is desired to know the effects that low gravity levels might have on the heat and mass transfer processes involved. The experiment module will contain the three liquid hydrogen tanks, valves, pressurization equipment, and instrumentation. At launch all the hydrogen will be in the largest tank, which has helium-purged MLI and is loaded and topped off by the hydrogen tanking system used for the Centaur upper stage of the Atlas. The two smaller tanks will be utilized in orbit for performing some of the experiments. The experiments are grouped into two classes on the basis of their priority, and include six regarded as enabling technology and nine regarded as enhancing technology.

  19. Characterization of Debris from the DebriSat Hypervelocity Test

    NASA Technical Reports Server (NTRS)

    Rivero, M.; Kleespies, J.; Patankar, K.; Fitz-Coy, N.; Liou, J.-C.; Sorge, M.; Huynh, T.; Opiela, J.; Krisko, P.; Cowardin, H.

    2015-01-01

    The DebriSat project is an effort by NASA and the DoD to update the standard break-up model for objects in orbit. The DebriSat object, a 56 kg representative LEO satellite, was subjected to a hypervelocity impact in April 2014. For the hypervelocity test, the representative satellite was suspended within a "soft-catch" arena formed by polyurethane foam panels to minimize the interactions between the debris generated from the hypervelocity impact and the metallic walls of the test chamber. After the impact, the foam panels and debris not caught by the panels were collected and shipped to the University of Florida where the project has now advanced to the debris characterization stage. The characterization effort has been divided into debris collection, measurement, and cataloguing. Debris collection and cataloguing involves the retrieval of debris from the foam panels and cataloguing the debris in a database. Debris collection is a three-step process: removal of loose debris fragments from the surface of the foam panels; X-ray imaging to identify/locate debris fragments embedded within the foam panel; extraction of the embedded debris fragments identified during the X-ray imaging process. As debris fragments are collected, they are catalogued into a database specifically designed for this project. Measurement involves determination of size, mass, shape, material, and other physical properties and well as images of the fragment. Cataloguing involves a assigning a unique identifier for each fragment along with the characterization information.

  20. On the Factorial Structure of the SAT and Implications for Next-Generation College Readiness Assessments

    ERIC Educational Resources Information Center

    Wiley, Edward W.; Shavelson, Richard J.; Kurpius, Amy A.

    2014-01-01

    The name "SAT" has become synonymous with college admissions testing; it has been dubbed "the gold standard." Numerous studies on its reliability and predictive validity show that the SAT predicts college performance beyond high school grade point average. Surprisingly, studies of the factorial structure of the current version…

  1. The Rainbow Project: Enhancing the SAT through Assessments of Analytical, Practical, and Creative Skills

    ERIC Educational Resources Information Center

    Sternberg, Robert J.

    2006-01-01

    This article describes the formulation and execution of the Rainbow Project, Phase I, funded by the College Board. Past data suggest that the SAT is a good predictor of performance in college. But in terms of the amount of variance explained by the SAT, there is room for improvement, as there would be for virtually any single test battery. Phase I…

  2. The Relationship between SAT Scores and Retention to the Third Year: 2006 Cohort. Statistical Report

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Patterson, Brian F.

    2010-01-01

    Results show that SAT performance is related to third year retention rates. Even after controlling for student and institutional characteristics, returners had higher SAT total scores than non-returners, and the performance gap is not due to differences in the demographic makeup of the two groups. Furthermore, while differences in retention can be…

  3. CloudSat Preps for Launch at Vandenberg Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The CloudSat spacecraft sits encapsulated within its Boeing Delta launch vehicle dual payload attach fitting at Vandenberg Air Force Base, Calif. CloudSat will share its ride to orbit late next month with NASA's CALIPSO spacecraft. The two spacecraft are designed to reveal the secrets of clouds and aerosols.

  4. PowerSat: A technology demonstration of a solar power satellite

    NASA Technical Reports Server (NTRS)

    Sigler, Douglas L. (Editor); Riedman, John; Duracinski, Jon; Edwards, Joe; Brown, Garry; Webb, Ron; Platzke, Mike; Yuan, Xiaolin; Rogers, Pete; Khan, Afsar

    1994-01-01

    PowerSat is a preliminary design strategy for microwave wireless power transfer of solar energy. Solar power satellites convert solar power into microwave energy and use wireless power transmission to transfer the power to the Earth's surface. The PowerSat project will show how new developments in inflatable technology can be used to deploy solar panels and phased array antennas.

  5. Non-"g" Residuals of the SAT and ACT Predict Specific Abilities

    ERIC Educational Resources Information Center

    Coyle, Thomas R.; Purcell, Jason M.; Snyder, Anissa C.; Kochunov, Peter

    2013-01-01

    This research examined whether non-"g" residuals of the SAT and ACT subtests, obtained after removing g, predicted specific abilities. Non-"g" residuals of the verbal and math subtests of the SAT and ACT were correlated with academic (verbal and math) and non-academic abilities (speed and shop), both based on the Armed Services…

  6. SAT Validity for Linguistic Minorities at the University of California, Santa Barbara

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Schlemer, Lizabeth

    2004-01-01

    The validity of the SAT as an admissions criterion for Latinos and Asian Americans who are not native English speakers was examined. The analyses, based on 1997 and 1998 UCSB freshmen, focused on the effectiveness of SAT scores and high school grade-point average (HSGPA) in predicting college freshman grade-point average (FGPA). When regression…

  7. New Perspectives on the Correlation of SAT Scores, High School Grades, and Socioeconomic Factors

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Greif Green, Jennifer

    2007-01-01

    In studies of the SAT, correlations of SAT scores, high school grades, and socioeconomic factors (SES) are usually obtained using a university as the unit of analysis. This approach obscures an important structural aspect of the data: The high school grades received by a given institution come from a large number of high schools, all of which have…

  8. The Achievement Gap: Should We Rely on SAT Scores to Tell Us Anything about It?

    ERIC Educational Resources Information Center

    Whittington, Dale

    2004-01-01

    Increasing numbers of students taking the SAT have declined to identify their race/ethnicity. I examined the impact of non-respondents on the validity of reported racial/ethnic differences and year-to-year changes in test performance. Using an analysis reported by Wainer (1988) and SAT data from 1996 to 2003, I confirmed Wainer's findings that…

  9. NASAs EDSN Aims to Overcome the Operational Challenges of CubeSat Constellations and Demonstrate an Economical Swarm of 8 CubeSats Useful for Space Science Investigations

    NASA Technical Reports Server (NTRS)

    Smith, Harrison Brodsky; Hu, Steven Hung Kee; Cockrell, James J.

    2013-01-01

    Operators of a constellation of CubeSats have to confront a number of daunting challenges that can be cost prohibitive, or operationally prohibitive, to missions that could otherwise be enabled by a satellite constellation. Challenges including operations complexity, intersatellite communication, intersatellite navigation, and time sharing tasks between satellites are all complicated by operating with the usual CubeSat size, power, and budget constraints. EDSN pioneers innovative solutions to these problems as they are presented on the nano-scale satellite platform.

  10. Crystal structure of di-aqua-(μ2-tri-ethyl-ene-tetra-minehexa-acetato)-dizinc tetra-hydrate.

    PubMed

    Liu, Huan; Lu, Li-Ping

    2015-03-01

    The reaction of ZnO and tri-ethyl-ene-tetra-minehexaacetic acid (H6TTHA) in aqueous solution after refluxing yields the binuclear title compound, [Zn2(C18H26N4O12)(H2O)2]·4H2O. There is a centre of symmetry in the [Zn2(H2TTHA)(H2O)2] mol-ecule in the crystalline state. Both Zn(II) ions are octahedrally surrounded and bound by an N2O3 donor set from the H2TTHA(4-) anion and a water mol-ecule; the N atoms are cis and the water mol-ecule is trans to an N atom. The Zn⋯Zn separation is 7.562 (1) Å. An intra-molecular C-H⋯O inter-action is observed and both carboxyl-ate H atoms are disordered over two adjacent sites. In the crystal, the components are linked by O-H⋯O and C-H⋯O hydrogen bonds generating a three-dimensonal network.

  11. Power generation and solar panels for an MSU CubeSat

    NASA Astrophysics Data System (ADS)

    Sassi, Soundouss

    This thesis is a power generation study of a proposed CubeSat at Mississippi State University (MSU). CubeSats are miniaturized satellites of 10 x 10 x 10 cm in dimension. Their power source once in orbit is the sun during daylight and the batteries during eclipse. MSU CubeSat is equipped with solar panels. This effort will discuss two types of cells: Gallium Arsenide and Silicon; and which one will suit MSU CubeSat best. Once the cell type is chosen, another decision regarding the electrical power subsystem will be made. Solar array design can only be done once the choice of the electrical power subsystem and the solar cells is made. Then the power calculation for different mission durations will start along with the sizing of the solar arrays. In the last part the batteries are introduced and discussed in order to choose one type of batteries for MSU CubeSat.

  12. Design of a terminal node controller hardware for CubeSat tracking applications

    NASA Astrophysics Data System (ADS)

    Ahmad, Y. A.; Nazim, N. J.; Yuhaniz, S. S.

    2016-10-01

    CubeSats enable low-cost experiment and missions to be performed by universities and research institution in space. CubeSats for research use UHF and VHF communication for its tracking and telemetry applications. The current practice of a CubeSat communication is to modify radio amateur's Terminal Node Controller (TNC) to enable data to be received in the ground station. The objective of this research is to design a hardware specifically for use as a TNC for CubeSat tracking applications. A TNC is developed as an interface to the terminal and to serve as data packetization platform. The modem is integrated with a microcontroller unit (MCU) and an audio amplifier to enable the audio signals to be smoothened, amplified and interfaced with the radio. The modem, MCU and audio amplifier circuitry are designed and integrated to form a TNC platform suitable for CubeSat communication.

  13. SmallSats, Iodine Propulsion Technology, Applications to Low-Cost Lunar Missions, and the Iodine Satellite (iSAT) Project

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.

    2014-01-01

    Closing Remarks: ?(1) SmallSats hold significant potential for future low cost high value missions; (2) Propulsion remains a key limiting capability for SmallSats that Iodine can address: High ISP * Density for volume constrained spacecraft; Indefinite quiescence, unpressurized and non-hazardous as a secondary payload; (3) Iodine enables MicroSat and SmallSat maneuverability: Enables transfer into high value orbits, constellation deployment and deorbit; (4) Iodine may enable a new class of planetary and exploration class missions: Enables GTO launched secondary spacecraft to transit to the moon, asteroids, and other interplanetary destinations for approximately 150 million dollars full life cycle cost including the launch; (5) ESPA based OTVs are also volume constrained and a shift from xenon to iodine can significantly increase the transfer vehicle change in volume capability including transfers from GTO to a range of Lunar Orbits; (6) The iSAT project is a fast pace high value iodine Hall technology demonstration mission: Partnership with NASA GRC and NASA MSFC with industry partner - Busek; (7) The iSAT mission is an approved project with PDR in November of 2014 and is targeting a flight opportunity in FY17.

  14. High Data Rates for AubieSat-2 A & B, Two CubeSats Performing High Energy Science in the Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Sims, William H.

    2015-01-01

    This paper will discuss a proposed CubeSat size (3 Units / 6 Units) telemetry system concept being developed at Marshall Space Flight Center (MSFC) in cooperation with Auburn University. The telemetry system incorporates efficient, high-bandwidth communications by developing flight-ready, low-cost, PROTOFLIGHT software defined radio (SDR) payload for use on CubeSats. The current telemetry system is slightly larger in dimension of footprint than required to fit within a 0.75 Unit CubeSat volume. Extensible and modular communications for CubeSat technologies will provide high data rates for science experiments performed by two CubeSats flying in formation in Low Earth Orbit. The project is a collaboration between the University of Alabama in Huntsville and Auburn University to study high energy phenomena in the upper atmosphere. Higher bandwidth capacity will enable high-volume, low error-rate data transfer to and from the CubeSats, while also providing additional bandwidth and error correction margin to accommodate more complex encryption algorithms and higher user volume.

  15. The Relationship between SAT® Scores and Retention to the Second Year: 2008 SAT Validity Sample. Statistical Report 2012-1

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Patterson, Brian F.

    2012-01-01

    The College Board formed a research consortium with four-year colleges and universities to build a national higher education database with the primary goal of validating the revised SAT®, which consists of three sections: critical reading (SAT-CR), mathematics (SAT-M), and writing (SAT-W), for use in college admission. A study by Mattern and…

  16. Propulsion System and Orbit Maneuver Integration in CubeSats: Trajectory Control Strategies Using Micro Ion Propulsion

    NASA Technical Reports Server (NTRS)

    Hudson, Jennifer; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Propulsion System and Orbit Maneuver Integration in CubeSats project aims to solve the challenges of integrating a micro electric propulsion system on a CubeSat in order to perform orbital maneuvers and control attitude. This represents a fundamentally new capability for CubeSats, which typically do not contain propulsion systems and cannot maneuver far beyond their initial orbits.

  17. CubeSat Cloud: A framework for distributed storage, processing and communication of remote sensing data on cubesat clusters

    NASA Astrophysics Data System (ADS)

    Challa, Obulapathi Nayudu

    CubeSat Cloud is a novel vision for a space based remote sensing network that includes a collection of small satellites (including CubeSats), ground stations, and a server, where a CubeSat is a miniaturized satellite with a volume of a 10x10x10 cm cube and has a weight of approximately 1 kg. The small form factor of CubeSats limits the processing and communication capabilities. Implemented and deployed CubeSats have demonstrated about 1 GHz processing speed and 9.6 kbps communication speed. A CubeSat in its current state can take hours to process a 100 MB image and more than a day to downlink the same, which prohibits remote sensing, considering the limitations in ground station access time for a CubeSat. This dissertation designs an architecture and supporting networking protocols to create CubeSat Cloud, a distributed processing, storage and communication framework that will enable faster execution of remote sensing missions on CubeSat clusters. The core components of CubeSat Cloud are CubeSat Distributed File System, CubeSat MapMerge, and CubeSat Torrent. The CubeSat Distributed File System has been created for distributing of large amounts of data among the satellites in the cluster. Once the data is distributed, CubeSat MapReduce has been created to process the data in parallel, thereby reducing the processing load for each CubeSat. Finally, CubeSat Torrent has been created to downlink the data at each CubeSat to a distributed set of ground stations, enabling faster asynchronous downloads. Ground stations send the downlinked data to the server to reconstruct the original image and store it for later retrieval. Analysis of the proposed CubeSat Cloud architecture was performed using a custom-designed simulator, called CubeNet and an emulation test bed using Raspberry Pi devices. Results show that for cluster sizes ranging from 5 to 25 small satellites, faster download speeds up to 4 to 22 times faster - can be achieved when using CubeSat Cloud, compared to a

  18. Deciphering Staphylococcus sciuri SAT-17 Mediated Anti-oxidative Defense Mechanisms and Growth Modulations in Salt Stressed Maize (Zea mays L.)

    PubMed Central

    Akram, Muhammad S.; Shahid, Muhammad; Tariq, Mohsin; Azeem, Muhammad; Javed, Muhammad T.; Saleem, Seemab; Riaz, Saba

    2016-01-01

    Soil salinity severely affects plant nutrient use efficiency and is a worldwide constraint for sustainable crop production. Plant growth-promoting rhizobacteria, with inherent salinity tolerance, are able to enhance plant growth and productivity by inducing modulations in various metabolic pathways. In the present study, we reported the isolation and characterization of a salt-tolerant rhizobacterium from Kallar grass [Leptochloa fusca (L.) Kunth]. Sequencing of the 16S rRNA gene revealed its lineage to Staphylococcus sciuri and it was named as SAT-17. The strain exhibited substantial potential of phosphate solubilization as well as indole-3-acetic acid production (up to 2 M NaCl) and 1-aminocyclopropane-1-carboxylic acid deaminase activity (up to 1.5 M NaCl). Inoculation of a rifampicin-resistant derivative of the SAT-17 with maize, in the absence of salt stress, induced a significant increase in plant biomass together with decreased reactive oxygen species and increased activity of cellular antioxidant enzymes. The derivative strain also significantly accumulated nutrients in roots and shoots, and enhanced chlorophyll and protein contents in comparison with non-inoculated plants. Similar positive effects were observed in the presence of salt stress, although the effect was more prominent at 75 mM in comparison to higher NaCl level (150 mM). The strain survived in the rhizosphere up to 30 days at an optimal population density (ca. 1 × 106 CFU mL-1). It was concluded that S. sciuri strain SAT-17 alleviated maize plants from salt-induced cellular oxidative damage and enhanced growth. Further field experiments should be conducted, considering SAT-17 as a potential bio-fertilizer, to draw parallels between PGPR inoculation, elemental mobility patterns, crop growth and productivity in salt-stressed semi-arid and arid regions. PMID:27375588

  19. Initial assessment of CryoSat-2 Performance.

    NASA Astrophysics Data System (ADS)

    Wingham, D.; Galin, N.; Ridout, A.; Cullen, R.; Giles, K. A.; Laxon, S. W.

    2011-12-01

    Following the launch of CryoSat-2 in April 2010, we have examined the performance of the CryoSat-2 SAR Interferometer over the continental ice sheets of Antarctica and Greenland, the Artic Ocean, and, for the purposes of calibration, over the oceans. Our aim has been to provide confirmation of the engineering performance of the radar interferometer, and to provide an initial geophysical validation of the resulting elevation measurements. We have confirmed the engineering performance at system level of the interferometer through performing a sequence of satellite rolls over the oceans, which provide a surface of known behavior and surface gradient. The activity has identified some errors in the SARIN L1b data products presently issued by ESA. Once corrected, the ocean calibration has demonstrated that the interferometer measures across-track surface slopes with a precision of 25 micro-radians and an accuracy of 10 micro-radians, which may be compared with a pre-launch estimation of 100 micro-radians; in short, the engineering performance greatly its the specification. The elevation measurement over the ice sheets combines the interferometer measurement of across track slope with the range measurement deduced from the SAR echoes. We have examined the performance of the range estimation, and determined the range precision to be 19 cm RMS at 20 Hz. We have examined the retrieval of the phase information over the ice sheets, and found the phase estimates to be robust and little affected by the uncertain ice sheet topography. Based on the calibration of the interferometer, the contribution of the across track slope error is, at 0.4 mm, negligible. While the quantity of data available to us that contains the corrections identified by the interferometer is limited, we have been able to confirm the range precision values from a limited cross-over analysis. Over marine sea ice, we have verified the discrimination of sea ice and ocean lead returns using contemporaneous SAR

  20. Interpretation of MODIS Cloud Images by CloudSat/CALIPSO Cloud Vertical Profiles

    NASA Astrophysics Data System (ADS)

    Wang, T.; Fetzer, E. J.; Wong, S.; Yue, Q.

    2015-12-01

    Clouds observed by passive remote-sensing imager (Aqua-MODIS) are collocated to cloud vertical profiles observed by active profiling sensors (CloudSat radar and CALIPSO lidar) at the pixel-scale. By comparing different layers of cloud types classified in the 2B-CLDCLASS-LIDAR product from CloudSat+CALIPSO to those cloud properties observed by MODIS, we evaluate the occurrence frequencies of cloud types and cloud-overlap in CloudSat+CALIPSO for each MODIS cloud regime defined by cloud optical depth (τ) and cloud-top pressure (P) histograms. We find that about 70% of MODIS clear sky agrees with the clear category in CloudSat+CALIPSO; whereas the remainder is either single layer (~25%) cirrus (Ci), low-level cumulus (Cu), stratocumulus (Sc), or multi-layer (<5%) clouds in CloudSat+CALIPSO. Under MODIS cloudy conditions, 60%, 28%, and 8% of the occurrences show single-, double-, and triple-layer clouds, respectively in CloudSat+CALIPSO. When MODIS identifies single-layer clouds, 50-60% of the MODIS low-level clouds are categorized as stratus (Sc) in CloudSat+CALIPSO. Over the tropics, ~70% of MODIS high and optically thin clouds (considered as cirrus in the histogram) is also identified as Ci in CloudSat+CALIPSO, and ~40% of MODIS high and optically thick clouds (considered as convective in the histogram) agrees with CloudSat+CALIPSO deep convections (DC). Over mid-latitudes these numbers drop to 45% and 10%, respectively. The best agreement occurs in tropical single-layer cloud regimes, where 90% of MODIS high-thin clouds are identified as Ci by CloudSat+CALIPSO and 60% of MODIS high-thick clouds are identified as DC. Worst agreement is found for multi-layer clouds, where cirrus on top of low- and mid-level clouds in MODIS are frequently categorized as high-thick clouds by passive imaging - among these only 5-12% are DC in CloudSat+CALIPSO. It is encouraging that both MODIS low-level clouds (regardless of optical thickness) and high-level thin clouds are consistently

  1. CubeSat: Colorado Student Space Weather Experiment

    NASA Astrophysics Data System (ADS)

    Li, X.; Palo, S. E.; Turner, D. L.; Gerhardt, D.; Redick, T.; Tao, J.

    2009-12-01

    Energetic particles, electrons and protons either directly associated with solar flares or trapped in the terrestrial radiation belt, have a profound space weather impact. A 3U CubeSat mission with a single instrument, Relativistic Electrons and Proton Telescope integrated little experiment (REPTile), is proposed to address fundamental questions relating to the relationship between solar flares and energetic particles and the acceleration and loss mechanism of outer radiation belt electrons. REPTile, in a highly inclined low earth orbit, will measure differential fluxes of relativistic electrons in the energy range of 0.5-3.5 MeV and protons in 10-40 MeV. This project is a collaborative effort between the Laboratory for Atmospheric and Space Physics and the Department of Aerospace Engineering Sciences at the University of Colorado, which includes the integration of students, faculty, and professional engineers.

  2. EarthSat spring wheat yield system test 1975

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The results of an operational test of the EarthSat System during the period 1 June - 30 August 1975 over the spring wheat regions of North Dakota, South Dakota, and Minnesota are presented. The errors associated with each sub-element of the system during the operational test and the sensitivity of the complete system and each major functional sub-element of the system to the observed errors were evaluated. Evaluations and recommendations for future operational users of the system include: (1) changes in various system sub-elements, (2) changes in the yield model to affect improved accuracy, (3) changes in the number of geobased cells needed to develop an accurate aggregated yield estimate, (4) changes associated with the implementation of future operational satellites and data processing systems, and (5) detailed system documentation.

  3. In-orbit performance of SXT aboard AstroSat

    NASA Astrophysics Data System (ADS)

    Singh, Kulinder Pal; Stewart, Gordon C.; Chandra, Sunil; Mukerjee, Kallol; Kotak, Sanket; Beardmore, Andy P.; Chitnis, Varsha; Dewangan, Gulab C.; Bhattacharyya, Sudip; Mirza, Irfan; Kamble, Nilima; Navalkar, Vinita; Shah, Harshit; Vishwakarma, S.; Koyande, J.

    2016-07-01

    A soft X-ray focusing Telescope (SXT) was launched in a near Earth, near equatorial orbit aboard the AstroSat on September 28th, 2015. The SXT electronics was switched on within 3 days of the launch and the first light was seen on October 26th, 2015 after a sequence of operations involving venting of the camera, cooling of the CCD, opening of the telescope door followed by the opening of the camera door. Several cosmic X-ray sources have been observed since then during the Performance Verification phase. A few near-simultaneous observations have also been carried out with the Swift observatory. The in-orbit performance of the SXT based on these observations is presented here.

  4. Globally Gridded Satellite (GridSat) Observations for Climate Studies

    NASA Technical Reports Server (NTRS)

    Knapp, Kenneth R.; Ansari, Steve; Bain, Caroline L.; Bourassa, Mark A.; Dickinson, Michael J.; Funk, Chris; Helms, Chip N.; Hennon, Christopher C.; Holmes, Christopher D.; Huffman, George J.; Kossin, James P.; Lee, Hai-Tien; Loew, Alexander; Magnusdottir, Gudrun

    2012-01-01

    Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them: there is no central archive of geostationary data for all international satellites, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multi-satellite climate studies. The International Satellite Cloud Climatology Project set the stage for overcoming these issues by archiving a subset of the full resolution geostationary data at approx.10 km resolution at 3 hourly intervals since 1983. Recent efforts at NOAA s National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in the netCDF format using standards that permit a wide variety of tools and libraries to quickly and easily process the data. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

  5. First results on GlioLab/GlioSat Precursors Missions

    NASA Astrophysics Data System (ADS)

    Cappelletti, Chantal; Notarangelo, Angelo; Demoss, Darrin; Carella, Massimo

    2012-07-01

    Since 2009 GAUSS group is involved in a joint collaboration with Morehead State University (MSU) Space Science Center and IRCCS Casa Sollievo della Sofferenza (CSS) research labs with the aim to design a biomedical project in order to investigate if the combined effects of microgravity conditions and ionizing radiation increase or decrease the survival rate of cancer cells. The biological sample consists of Glioblastoma cancer cell line ANGM-CSS. Glioblastoma is a kind of cancer that can be treated after surgery only by radiotherapy using ionizing radiation. This treatment, anyway, results in a very low survival rate. This project uses different university space platforms: a CubeLab, named GlioLab, on board the International Space Station and the university microsatellite UniSat-5 designed by GAUSS. In addition a GlioLab/GlioSat precursor experiment has already flown two times with the Space Shuttle during the missions STS-134 and STS-135. The phase 0 or the precursor of GlioLab uses a COTS system, named Liquid Mixing Apparatus (LMA), to board the biological samples inside the Space Shuttle for thirty day . The LMA allows to board liquids inside a vial but is not equipped with environment control system. After landing the samples were investigated by researchers at CSS in Italy and at MSU in Kentucky. This paper deals with the experimental set up and the results obtained during the STS-134 and STS-135 missions and with the new evidences on the behavior of this kind of cancer. In particular the results obtained on the DNA analysis give a confirmation of the original idea of GLioLab/Gliosat project justifying the development of the two systems.

  6. Survey on the implementation and reliability of CubeSat electrical bus interfaces

    NASA Astrophysics Data System (ADS)

    Bouwmeester, Jasper; Langer, Martin; Gill, Eberhard

    2016-09-01

    This paper provides results and conclusions on a survey on the implementation and reliability aspects of CubeSat bus interfaces, with an emphasis on the data bus and power distribution. It provides recommendations for a future CubeSat bus standard. The survey is based on a literature study and a questionnaire representing 60 launched CubeSats and 44 to be launched CubeSats. It is found that the bus interfaces are not the main driver for mission failures. However, it is concluded that the Inter Integrated Circuit (I2C) data bus, as implemented in a great majority of the CubeSats, caused some catastrophic satellite failures and a vast amount of bus lockups. The power distribution may lead to catastrophic failures if the power lines are not protected against overcurrent. A connector and wiring standard widely implemented in CubeSats is based on the PC/104 standard. Most participants find the 104 pin connector of this standard too large. For a future CubeSat bus interface standard, it is recommended to implement a reliable data bus, a power distribution with overcurrent protection and a wiring harness with smaller connectors compared with PC/104.

  7. Activation of SAT1 engages polyamine metabolism with p53-mediated ferroptotic responses.

    PubMed

    Ou, Yang; Wang, Shang-Jui; Li, Dawei; Chu, Bo; Gu, Wei

    2016-11-01

    Although p53-mediated cell-cycle arrest, senescence, and apoptosis remain critical barriers to cancer development, the emerging role of p53 in cell metabolism, oxidative responses, and ferroptotic cell death has been a topic of great interest. Nevertheless, it is unclear how p53 orchestrates its activities in multiple metabolic pathways into tumor suppressive effects. Here, we identified the SAT1 (spermidine/spermine N(1)-acetyltransferase 1) gene as a transcription target of p53. SAT1 is a rate-limiting enzyme in polyamine catabolism critically involved in the conversion of spermidine and spermine back to putrescine. Surprisingly, we found that activation of SAT1 expression induces lipid peroxidation and sensitizes cells to undergo ferroptosis upon reactive oxygen species (ROS)-induced stress, which also leads to suppression of tumor growth in xenograft tumor models. Notably, SAT1 expression is down-regulated in human tumors, and CRISPR-cas9-mediated knockout of SAT1 expression partially abrogates p53-mediated ferroptosis. Moreover, SAT1 induction is correlated with the expression levels of arachidonate 15-lipoxygenase (ALOX15), and SAT1-induced ferroptosis is significantly abrogated in the presence of PD146176, a specific inhibitor of ALOX15. Thus, our findings uncover a metabolic target of p53 involved in ferroptotic cell death and provide insight into the regulation of polyamine metabolism and ferroptosis-mediated tumor suppression.

  8. CpSAT-1, a transcribed satellite sequence from the codling moth, Cydia pomonella.

    PubMed

    Věchtová, Pavlína; Dalíková, Martina; Sýkorová, Miroslava; Žurovcová, Martina; Füssy, Zoltán; Zrzavá, Magda

    2016-08-01

    Satellite DNA (satDNA) is a non-coding component of eukaryotic genomes, located mainly in heterochromatic regions. Relevance of satDNA began to emerge with accumulating evidence of its potential yet hardly comprehensible role that it can play in the genome of many organisms. We isolated the first satDNA of the codling moth (Cydia pomonella, Tortricidae, Lepidoptera), a species with holokinetic chromosomes and a single large heterochromatic element, the W chromosome in females. The satDNA, called CpSAT-1, is located on all chromosomes of the complement, although in different amounts. Surprisingly, the satellite is almost missing in the heterochromatic W chromosome. Additionally, we isolated mRNA from all developmental stages (1st-5th instar larva, pupa, adult), both sexes (adult male and female) and several tissues (Malpighian tubules, gut, heart, testes, and ovaries) of the codling moth and showed the CpSAT-1 sequence was transcribed in all tested samples. Using CpSAT-1 specific primers we amplified, cloned and sequenced 40 monomers from cDNA and gDNA, respectively. The sequence analysis revealed a high mutation rate and the presence of potentially functional motifs, mainly in non-conserved regions of the monomers. Both the chromosomal distribution and the sequence analysis suggest that CPSAT-1 has no function in the C. pomonella genome.

  9. How CubeSats contribute to Science and Technology in Astronomy and Astrophysics

    NASA Astrophysics Data System (ADS)

    Cahoy, Kerri Lynn; Douglas, Ewan; Carlton, Ashley; Clark, James; Haughwout, Christian

    2017-01-01

    CubeSats are nanosatellites, spacecraft typically the size of a shoebox or backpack. CubeSats are made up of one or more 10 cm x 10 cm x 10 cm units weighing 1.33 kg (each cube is called a “U”). CubeSats benefit from relatively easy and inexpensive access to space because they are designed to slide into fully enclosed spring-loaded deployer pods before being attached as an auxiliary payload to a larger vehicle, without adding risk to the vehicle or its primary payload(s). Even though CubeSats have inherent resource and aperture limitations due to their small size, over the past fifteen years, researchers and engineers have miniaturized components and subsystems, greatly increasing the capabilities of CubeSats. We discuss how state of the art CubeSats can address both science objectives and technology objectives in Astronomy and Astrophysics. CubeSats can contribute toward science objectives such as cosmic dawn, galactic evolution, stellar evolution, extrasolar planets and interstellar exploration.CubeSats can contribute to understanding how key technologies for larger missions, like detectors, microelectromechanical systems, and integrated optical elements, can not only survive launch and operational environments (which can often be simulated on the ground), but also meet performance specifications over long periods of time in environments that are harder to simulate properly, such as ionizing radiation, the plasma environment, spacecraft charging, and microgravity. CubeSats can also contribute to both science and technology advancements as multi-element space-based platforms that coordinate distributed measurements and use formation flying and large separation baselines to counter their restricted individual apertures.

  10. Pi-Sat: A Low Cost Small Satellite and Distributed Spacecraft Mission System Test Platform

    NASA Technical Reports Server (NTRS)

    Cudmore, Alan

    2015-01-01

    Current technology and budget trends indicate a shift in satellite architectures from large, expensive single satellite missions, to small, low cost distributed spacecraft missions. At the center of this shift is the SmallSatCubesat architecture. The primary goal of the Pi-Sat project is to create a low cost, and easy to use Distributed Spacecraft Mission (DSM) test bed to facilitate the research and development of next-generation DSM technologies and concepts. This test bed also serves as a realistic software development platform for Small Satellite and Cubesat architectures. The Pi-Sat is based on the popular $35 Raspberry Pi single board computer featuring a 700Mhz ARM processor, 512MB of RAM, a flash memory card, and a wealth of IO options. The Raspberry Pi runs the Linux operating system and can easily run Code 582s Core Flight System flight software architecture. The low cost and high availability of the Raspberry Pi make it an ideal platform for a Distributed Spacecraft Mission and Cubesat software development. The Pi-Sat models currently include a Pi-Sat 1U Cube, a Pi-Sat Wireless Node, and a Pi-Sat Cubesat processor card.The Pi-Sat project takes advantage of many popular trends in the Maker community including low cost electronics, 3d printing, and rapid prototyping in order to provide a realistic platform for flight software testing, training, and technology development. The Pi-Sat has also provided fantastic hands on training opportunities for NASA summer interns and Pathways students.

  11. Mothership - Affordable Exploration of Planetary Bodies through Individual Nano-Sats and Swarms

    NASA Astrophysics Data System (ADS)

    DiCorcia, James D.; Ernst, Sebastian M.; Grace, J. Mike; Gump, David P.; Lewis, John S.; Foulds, Craig F.; Faber, Daniel R.

    2015-04-01

    One concept to enable broad participation in the scientific exploration of small bodies is the Mothership mission architecture which delivers third-party nano-sats, experiments, and sensors to a near Earth asteroid or comet. Deep Space Industries' Mothership service includes delivery of nano-sats, communication to Earth, and visuals of the asteroid surface and surrounding area. It allows researchers to house their instruments in a low-cost nano-sat platform that does not require the high-performance propulsion or deep space communication capabilities that otherwise would be required for a solo asteroid mission. This enables organizations with relatively low operating budgets to closely examine an asteroid with highly specialized sensors of their own choosing, while the nano-sats can be built or commissioned by a variety of smaller institutions, companies, or agencies. In addition, the Mothership and its deployed nano-sats can offer a platform for instruments which need to be distributed over multiple spacecraft. The Mothership is designed to carry 10 to 12 nano-sats, based upon a variation of the Cubesat standard, with some flexibility on the specific geometry. The Deep Space Nano-Sat reference design is a 14.5 cm cube, which accomodates the same volume as a traditional 3U Cubesat. This design was found to be more favorable for deep space due to its thermal characteristics. The CubeSat standard was originally designed with operations in low Earth orbit in mind. By deliberately breaking the standard, Deep Space Nano-Sats offer better performance with less chance of a critical malfunction in the more hostile deep space environment. The first mission can launch as early as Q4 2017, with subsequent, regular launches through the 2020's.

  12. Improved Oceanographic Measurements with CryoSat SAR Altimetry: Applications to the Coastal Zone and Arctic

    NASA Astrophysics Data System (ADS)

    Cotton, D.; Garcia, P. N.; Cancet, M.; Andersen, O.; Stenseng, L.; Martin, F.; Cipollini, P.; Calafat, F. M.; Passaro, M.; Restano, M.; Ambrozio, A.; Benveniste, J.

    2016-08-01

    The ESA CryoSat-2 mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar (SAR) mode. Although the prime objective of the CryoSat-2 mission is dedicated to monitoring land and marine ice, the SAR mode capability of the CryoSat-2 SIRAL altimeter also presents significant potential benefits for ocean applications including improved range precision and finer along track spatial resolution.The "CryoSat Plus for Oceans" (CP4O) project, supported by the ESA Support to Science Element (STSE) Programme and by CNES, was dedicated to the exploitation of CryoSat-2 data over the open and coastal ocean. The general objectives of the CP4O project were: to build a sound scientific basis for new oceanographic applications of CryoSat-2 data; to generate and evaluate new methods and products that will enable the full exploitation of the capabilities of the CryoSat-2 SIRAL altimeter, and to ensure that the scientific return of the CryoSat-2 mission is maximised. Cotton et al, (2015) is the final report on this work.However, whilst the results from CP4O were highly promising and confirmed the potential of SAR altimetry to support new scientific and operational oceanographic applications, it was also apparent that further work was needed in some key areas to fully realise the original project objectives. Thus additional work in four areas has been supported by ESA under a Contract Change Notice:• Developments in SARin data processing for Coastal Altimetry (isardSAT).• Implementation of a Regional Tidal Atlas for the Arctic Ocean (Noveltis and DTU Space).• Improvements to the SAMOSA re-tracker: Implementation and Evaluation- Optimised Thermal Noise Estimation. (Starlab and SatOC).• Extended evaluation of CryoSat-2 SAR data for Coastal Applications (NOC).This work was managed by SatOC. The results of this work are summarized here. Detailed information regarding the CP4O project can be found at: http://www.satoc.eu/projects/CP4O/

  13. Characterisation of a SAT-1 outbreak of foot-and-mouth disease in captive African buffalo (Syncerus caffer): clinical symptoms, genetic characterisation and phylogenetic comparison of outbreak isolates.

    PubMed

    Vosloo, W; de Klerk, L-M; Boshoff, C I; Botha, B; Dwarka, R M; Keet, D; Haydon, D T

    2007-03-10

    African buffalo (Syncerus caffer) play an important role in the maintenance of the SAT types of foot-and-mouth disease (FMD) in southern Africa. These long-term carriers mostly become sub-clinically infected, maintaining the disease and posing a threat to other susceptible wildlife and domestic species. During an unrelated bovine tuberculosis experiment using captive buffalo in the Kruger National Park (KNP), an outbreak of SAT-1 occurred and was further investigated. The clinical signs were recorded and all animals demonstrated significant weight loss and lymphopenia that lasted 100 days. In addition, the mean cell volume and mean cell haemoglobin values were significantly higher than before the outbreak started. Virus was isolated from several buffalo over a period of 167 days post infection and the molecular clock estimated to be 3 x 10(-5) nucleotide substitutions per site per day. Seven amino acid changes occurred of which four occurred in hypervariable regions previously described for SAT-1. The genetic relationship of the outbreak virus was compared to buffalo viruses previously obtained from the KNP but the phylogeny was largely unresolved, therefore the relationship of this outbreak strain to others isolated from the KNP remains unclear.

  14. Extending Clause Learning of SAT Solvers with Boolean Gröbner Bases

    NASA Astrophysics Data System (ADS)

    Zengler, Christoph; Küchlin, Wolfgang

    We extend clause learning as performed by most modern SAT Solvers by integrating the computation of Boolean Gröbner bases into the conflict learning process. Instead of learning only one clause per conflict, we compute and learn additional binary clauses from a Gröbner basis of the current conflict. We used the Gröbner basis engine of the logic package Redlog contained in the computer algebra system Reduce to extend the SAT solver MiniSAT with Gröbner basis learning. Our approach shows a significant reduction of conflicts and a reduction of restarts and computation time on many hard problems from the SAT 2009 competition.

  15. River flood events in Thailand and Bangladesh observed by CryoSat-2

    NASA Astrophysics Data System (ADS)

    Nielsen, Karina; Villadsen, Heidi; Andersen, Ole; Stenseng, Lars; Knudsen, Per

    2015-04-01

    The high along track resolution of the SIRAL altimeter carried on-board CryoSat-2 offers a wide range of unique opportunities for satellite monitoring. This study focuses on the ability of CryoSat-2 to detect the effects of flood events such as increased river levels and inundation of land. Here we study two flood events; the Bangladesh flood event of June 2012 and the flooding in Thailand that lasted between July 2011 and January 2012. The flooding in these areas was caused by abnormal monsoonal rainfall and affected millions of people. We process CryoSat-2 level 1b SAR mode data to derive water levels for the areas and compare these levels before, during and after the flooding events. Other parameters such as the backscatter coefficient and pulse peakiness are also considered. To verify the extent of the flooding observed by CryoSat-2 we compare with independent sources such as Landsat images.

  16. CS2SAT: THE CONTROL SYSTEMS CYBER SECURITY SELF-ASSESSMENT TOOL

    SciTech Connect

    Kathleen A. Lee

    2008-01-01

    The Department of Homeland Security National Cyber Security Division has developed the Control System Cyber Security Self-Assessment Tool (CS2SAT) that provides users with a systematic and repeatable approach for assessing the cyber-security posture of their industrial control system networks. The CS2SAT was developed by cyber security experts from Department of Energy National Laboratories and with assistance from the National Institute of Standards and Technology. The CS2SAT is a desktop software tool that guides users through a step-by-step process to collect facility-specific control system information and then makes appropriate recommendations for improving the system’s cyber-security posture. The CS2SAT provides recommendations from a database of industry available cyber-security practices, which have been adapted specifically for application to industry control system networks and components. Each recommendation is linked to a set of actions that can be applied to remediate-specific security vulnerabilities.

  17. MinXSS CubeSat Brings New Information to Study of Solar Flares

    NASA Video Gallery

    Along with the visible light and warmth constantly emitted by our sun comes a whole spectrum of X-ray and ultraviolet radiation that streams toward Earth. A new CubeSat – a miniature satellite that...

  18. Flight Technical Error Analysis of the SATS Higher Volume Operations Simulation and Flight Experiments

    NASA Technical Reports Server (NTRS)

    Williams, Daniel M.; Consiglio, Maria C.; Murdoch, Jennifer L.; Adams, Catherine H.

    2005-01-01

    This paper provides an analysis of Flight Technical Error (FTE) from recent SATS experiments, called the Higher Volume Operations (HVO) Simulation and Flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with today s system (baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to today s system. In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative Human in the Loop (HITL) studies of SATS HVO and Baseline operations.

  19. Achieving Visionary Planetary Science Goals with Deep Space CubeSats

    NASA Astrophysics Data System (ADS)

    Hardgrove, C.; Ehlmann, B. L.

    2017-02-01

    Throughout the 2020’s–2050’s, CubeSats will help enrich the scientific return from large planetary science missions by providing high-risk, high-reward complementary data to the primary spacecraft mission.

  20. Pulsed Plasma Propulsion - Making CubeSat Missions Beyond Low Earth Orbit Possible

    NASA Astrophysics Data System (ADS)

    Northway, P.

    2015-12-01

    As CubeSat missions become more and more popular means of scientific exploration of space, the current direction of interest is to utilize them in areas beyond low earth orbit. The University of Washington CubeSat program focuses on examining possible mission scenarios in addition to technology development and integration. Specifically, we are developing an inert CubeSat propulsion system in the form of a pulsed plasma thruster (PPT) capable of orbit maneuvers. Such a system would allow for missions at the Earth beyond LEO, extended missions at the Moon, and even missions at Europa, when assisted to the Jovian system. We will discuss how starting with a CubeSat design using PPTs for orbital maneuvers, other developing compact technology can be adapted to create a full suite of systems that would meet the requirements for a mission traveling outside low earth orbit.

  1. Preliminary Characterization Results from the DebriSat Project

    NASA Technical Reports Server (NTRS)

    Rivero, M.; Shiotani, B.; Kleespies, J.; Toledo-Burdett, R.; Moraguez, M.; Carrasquila, M.; Fitz-Coy, N.; Liou, J.-C.; Sorge, M.; Huynh, T.

    2016-01-01

    The DebriSat project is a continuing effort sponsored by NASA and DoD to update existing break-up models using data obtained from two separate hypervelocity impact tests used to simulate on-orbit collisions. To protect the fragments resulting from the impact tests, "soft-catch" arenas made of polyurethane foam panels were utilized. After each impact test, the test chamber was cleaned and debris resulting from the catastrophic demise of the test article were collected and shipped to the University of Florida for post-impact processing. The post-impact processing activities include collecting, characterizing, and cataloging of the fragments. Since the impact tests, a team of students has been working to characterize the fragments in terms of their mass, size, shape, color and material content. The focus of the 20 months since the impact tests has been on the collection of 2 millimeters- and larger fragments resulting from impact test on the 56 kilogram-representative LEO (Low Earth Orbit) satellite referred to as DebriSat. To date we have recovered in excess of 115,000 fragments, 30,000 more than the prediction of 85,000 fragments from the existing model. We continue to collect fragments but have transitioned to the characterization phase of the post-impact activities. Since the start of the characterization phase, the focus has been to utilize automation to (i) expedite fragment characterization process and (ii) minimize human-in-the- loop. We have developed and implemented such automated processes; e.g., we have automated the data entry process to reduce operator errors during transcription of the measurement data. However, at all steps of the process, there is human oversight to ensure the integrity of the data. Additionally, we have developed and implemented repeatability and reproducibility tests to ensure that the instrumentation used in the characterization process is accurate and properly calibrated. In this paper, the implemented processes are described and

  2. Molecular differentiation and phylogenetic analysis of the Egyptian foot-and-mouth disease virus SAT2.

    PubMed

    El-Shehawy, Laila I; Abu-Elnaga, Hany I; Rizk, Sonia A; Abd El-Kreem, Ahmed S; Mohamed, A A; Fawzy, Hossam G

    2014-03-01

    In February 2012, a massive new foot-and-mouth disease (FMD) outbreak struck Egypt. In this work, one-step RT-PCR assays were used for in-house detection and differentiation of foot-and-mouth disease virus (FMDV) in Egypt in this year using pan-serotypic and serotype-targeting sequence primers. FMDV SAT2 was the dominant virus in the examined isolates from the epidemic. The complete VP1 coding regions of two isolates were sequenced. The two isolates had 99.2 % sequence identity to most contemporary Egyptian SAT2 reference viruses, whereas they had 89.7-90.1 % identity to the SAT2/EGY/2/2012 isolate, which was collected from Alexandria, Egypt, and previously sequenced by WRLFMD. Phylogenetic analysis showed that Egypt had one topotype and two lineage of FMDV SAT2 in 2012. The Egyptian and the Palestinian 2012 strains were associated mainly with topotype VII, lineage SAT2/VII/Ghb-12, while the virus isolated from Alexandria Governorate belonged to the SAT2/VII/Alx-12 lineage. Topotype VII also comprised lineages that included strains isolated from Libya in 2012 and 2003. Furthermore, within the same topotype, the Egyptian SAT2/2012 isolates were related to strains from Saudi Arabia, Sudan, Eritrea, Cameroon and Nigeria. Nevertheless, more epidemiological work with neighboring countries is needed to prevent cross-border spread of disease and to reach a precise conclusion about the origin of the 2012 FMDV SAT2 emergency in the Middle East.

  3. Abstract Model of the SATS Concept of Operations: Initial Results and Recommendations

    NASA Technical Reports Server (NTRS)

    Dowek, Gilles; Munoz, Cesar; Carreno, Victor A.

    2004-01-01

    An abstract mathematical model of the concept of operations for the Small Aircraft Transportation System (SATS) is presented. The Concept of Operations consist of several procedures that describe nominal operations for SATS, Several safety properties of the system are proven using formal techniques. The final goal of the verification effort is to show that under nominal operations, aircraft are safely separated. The abstract model was written and formally verified in the Prototype Verification System (PVS).

  4. Study Pollution Impacts on Upper-Tropospheric Clouds with Aura, CloudSat, and CALIPSO Data

    NASA Technical Reports Server (NTRS)

    Wu, Dong

    2007-01-01

    This viewgraph presentation reviews the impact of pollution on clouds in the Upper Troposphere. Using the data from the Aura Microwave Limb Sounder (MLS), CloudSat, CALIPSO the presentation shows signatures of pollution impacts on clouds in the upper troposphere. The presentation demonstrates the complementary sensitivities of MLS , CloudSat and CALIPSO to upper tropospheric clouds. It also calls for careful analysis required to sort out microphysical changes from dynamical changes.

  5. Space Environment NanoSat Experiment (SENSE) - A New Frontier in Operational Space Environmental Monitoring (Invited)

    NASA Astrophysics Data System (ADS)

    Kalamaroff, K. I.; Thompson, D. C.; Cooke, D. L.; Gentile, L. C.; Bonito, N. A.; La Tour, P.; Sondecker, G.; Bishop, R. L.; Nicholas, A. C.; Doe, R. A.

    2013-12-01

    The Space Environmental NanoSat Experiment (SENSE) program is a rapid development effort of the USAF Space and Missiles Center Development Planning Directorate (SMC/XR) which will demonstrate the capability of NanoSats to perform space missions in an affordable and resilient manner. The three primary objectives for the SENSE mission are: 1) to develop best practices for operational CubeSat/NanoSat procurement, development, test, and operations; 2) to mature CubeSat bus and sensor component technology readiness levels; and 3) to demonstrate the operational utility of CubeSat measurements by flowing validated, low-latency data into operational space weather models. SENSE consists of two 3-U CubeSats built by Boeing Phantom Works. Both satellites are 3-axis stabilized with star cameras for attitude determination and are equipped with a Compact Total Electron Density Sensor (CTECS) to provide radio occultation measurements of total electron content and L-band scintillation. One satellite has a Cubesat Tiny Ionospheric Photometer (CTIP) monitoring 135.6 nm photons produced by the recombination of O+ ions and electrons. The other satellite has a Wind Ion Neutral Composite Suite (WINCS) to acquire simultaneous co-located, in situ measurements of atmospheric and ionospheric density, composition, temperature and winds/drifts. Mission data will be used to improve current and future space weather models and demonstrate the utility of data from CubeSats for operational weather requirements. Launch is scheduled for November 2013, and we will discuss the first 30 days of on-orbit operations.

  6. Study of LEO-SAT microwave link for broad-band mobile satellite communication system

    NASA Technical Reports Server (NTRS)

    Fujise, Masayuki; Chujo, Wataru; Chiba, Isamu; Furuhama, Yoji; Kawabata, Kazuaki; Konishi, Yoshihiko

    1993-01-01

    In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

  7. Application of parallel algorithmic differentiation to optimal CubeSat trajectory design

    NASA Astrophysics Data System (ADS)

    Ghosh, Alexander; Coverstone, Victoria

    2017-01-01

    CubeSats, the class of small standardized satellites, are becoming a viable scientific research platform. At present, a variety of high value Earth Science missions require multiple collecting instruments on separate platforms maintained in precise configurations. A new software tool was created to compute propellant-minimizing maneuvers for multiple CubeSats for use with mission preliminary design. This tool incorporates parallelization of the derivative calculations, and demonstrates speed improvements over previous parallel formulations of small satellite cooperative trajectory design problems.

  8. Electrical Power Subsystem Integration and Test for the NPS Solar Cell Array Tester CubeSat

    DTIC Science & Technology

    2010-12-01

    a standardized CubeSat architecture developed by Pumpkin Inc. The CSK allows rapid integration of a fully functional CubeSat that conforms to...the FM430 command and data handling system (C&DH). The FM430 real time operating system (RTOS) is Salvo developed by Pumpkin Inc. COTS components...manufactured by Pumpkin Inc. This subassembly houses the MSP430F1612 microcontroller, which serves as the central processing unit (CPU) for SCAT

  9. SeaSat-A Satellite Scatterometer Mission Summary and Engineering Assessment Report

    NASA Technical Reports Server (NTRS)

    Johnson, J. W.; Lee, W. H.; Williams, L. A., Jr.

    1979-01-01

    The SeaSat-A satellite was launched on June 26, 1978 and operated in orbit through October 9, 1978. The SeaSat-A satellite scatterometer ocean surface wind field sensor began taking data on July 10, 1978 with virtually continuous operation for 95-1/2 days. A review of mission events significant to the scatterometer and a report on the hardware and software engineering assessment are presented.

  10. Integration of a MicroCAT Propulsion System and a PhoneSat Bus into a 1.5U CubeSat

    NASA Technical Reports Server (NTRS)

    Agasid, Elwood Floyd; Perez, Andres Dono; Gazulla, Oriol Tintore; Trinh, Greenfield Tran; Uribe, Eddie Anthony; Keidar, Michael; Haque, Samudra; Teel, George

    2014-01-01

    NASA Ames Research Center and the George Washington University have developed an electric propulsion subsystem that can be integrated into the PhoneSat bus. Experimental tests have shown a reliable performance by firing three different thrusters at various frequencies in vacuum conditions. The three thrusters were controlled by a SmartPhone that was running the PhoneSat software. The subsystem is fully operational and it requires low average power to function (about 0.1 W). The interface consists of a microcontroller that sends a trigger pulses to the PPU (Plasma Processing Unit), which is responsible for the thruster operation. Frequencies ranging from 1 to 50Hz have been tested, showing a strong flexibility. A SmartPhone acts as the main user interface for the selection of commands that control the entire system. The micro cathode arc thruster MicroCAT provides a high 1(sub sp) of 3000s that allows a 4kg satellite to obtain a (delta)V of 300m/s. The system mass is only 200g with a total of volume of 200(cu cm). The propellant is based on a solid cylinder made of Titanium, which is the cathode at the same time. This simplicity in the design avoids miniaturization and manufacturing problems. The characteristics of this thruster allow an array of MicroCATs to perform attitude control and orbital correcton maneuvers that will open the door for the implementation of an extensive collection of new mission concepts and space applications for CubeSats. NASA Ames is currently working on the integration of the system to fit the thrusters and PPU inside a 1.5U CubeSat together with the PhoneSat bus into a 1.5U CubeSat. This satellite is intended to be deployed from the ISS in 2015 and test the functionality of the thrusters by spinning the satellite around its long axis and measure the rotational speed with the phone byros. This test flight will raise the TRL of the propulsion system from 5 to 7 and will be a first test for further CubeSats with propulsion systems, a key

  11. Characterization of spacecraft and environmental disturbances on a SmallSat

    NASA Technical Reports Server (NTRS)

    Johnson, Thomas A.; Nguyen, Dung Phu Chi; Cuda, Vince; Freesland, Doug

    1994-01-01

    The objective of this study is to model the on-orbit vibration environment encountered by a SmallSat. Vibration control issues are common to the Earth observing, imaging, and microgravity communities. A spacecraft may contain dozens of support systems and instruments each a potential source of vibration. The quality of payload data depends on constraining vibration so that parasitic disturbances do not affect the payload's pointing or microgravity requirement. In practice, payloads are designed incorporating existing flight hardware in many cases with nonspecific vibration performance. Thus, for the development of a payload, designers require a thorough knowledge of existing mechanical devices and their associated disturbance levels. This study evaluates a SmallSat mission and seeks to answer basic questions concerning on-orbit vibration. Payloads were considered from the Earth observing, microgravity, and imaging communities. Candidate payload requirements were matched to spacecraft bus resources of present day SmallSats. From the set of candidate payloads, the representative payload GLAS (Geoscience Laser Altimeter System) was selected. The requirements of GLAS were considered very stringent for the 150 - 500 kg class of payloads. Once the payload was selected, a generic SmallSat was designed in order to accommodate the payload requirements (weight, size, power, etc.). This study seeks to characterize the on-orbit vibration environment of a SmallSat designed for this type of mission and to determine whether a SmallSat can provide the precision pointing and jitter control required for earth observing payloads.

  12. Using Additive Manufacturing to Print a CubeSat Propulsion System

    NASA Technical Reports Server (NTRS)

    Marshall, William M.

    2015-01-01

    CubeSats are increasingly being utilized for missions traditionally ascribed to larger satellites CubeSat unit (1U) defined as 10 cm x 10 cm x 11 cm. Have been built up to 6U sizes. CubeSats are typically built up from commercially available off-the-shelf components, but have limited capabilities. By using additive manufacturing, mission specific capabilities (such as propulsion), can be built into a system. This effort is part of STMD Small Satellite program Printing the Complete CubeSat. Interest in propulsion concepts for CubeSats is rapidly gaining interest-Numerous concepts exist for CubeSat scale propulsion concepts. The focus of this effort is how to incorporate into structure using additive manufacturing. End-use of propulsion system dictates which type of system to develop-Pulse-mode RCS would require different system than a delta-V orbital maneuvering system. Team chose an RCS system based on available propulsion systems and feasibility of printing using a materials extrusion process. Initially investigated a cold-gas propulsion system for RCS applications-Materials extrusion process did not permit adequate sealing of part to make this a functional approach.

  13. CubeSat-Associated Radiation Belt Research: Recent and Upcoming Observations

    NASA Astrophysics Data System (ADS)

    Blum, Lauren; Li, Xinlin; Schiller, Quintin

    2016-07-01

    Interest in CubeSats has grown dramatically in the past decade within the space physics community. While CubeSats are generally accepted now to be useful tools for education and technology development/demonstration, their ability to provide scientific value is often still questioned. Radiation belt physics, however, is one area in which the scientific utility of these small platforms has been demonstrated and continues to offer great promise. The Colorado Student Space Weather Experiment (CSSWE) CubeSat, designed, built, tested, and operated by students at University of Colorado with mentoring from LASP professionals, was one of the first of now a long line of CubeSats designed to study radiation belt dynamics. Launched in September 2012, just a few weeks after NASA's Van Allen Probes, CSSWE provided valuable measurements of energetic electrons and protons from low-Earth orbit for two years, well beyond its nominal 3-month mission lifetime. The status of and results from CSSWE will be presented, with an emphasis on how these measurements have been combined with those from balloons and larger satellite missions to better understand radiation belt electron acceleration and loss processes. Some highlights from other radiation belt-related CubeSats will also be presented, along with upcoming missions. Radiation belt studies are a prime example of how small inexpensive CubeSats can be used to provide valuable scientific measurements and complement larger missions.

  14. PSDE/SAT-2: Communication system architecture study, executive summary

    NASA Astrophysics Data System (ADS)

    The PSDE/SAT-2 multimission satellite designed to offer a flight opportunity to different experimental communication payloads and verify the feasibility of advanced space technologies is described. It was conceived for expriment in the framework of the European DRS (Data Relay Satellite) program thus providing intersatellite and interorbit communication links, but also experimental and preoperative services. Payloads include optical communication single access payload (LSA); S-Band single access payload; S-Band multiple access payload; land mobile experimental payload; navigation payload; 40/50 GHz communication payload; and millimeter wave propagation payload. The orbital slot and interference analysis identified a limited number of orbital positions for the mission interleaved between Eutelsat satellites (i.e., 14 deg 30 min E and 17 deg 30 min E). A coordination is required in Ku-Band with Eutelsat satellites and in Ka-Band with ITALSAT (Italy) and TOR-12 (USSR) systems. The link budget analysis shows that the feeder link can be correctly dimensioned assuming the ground segment as specified by ESA and the feeder link payload interface compatible with the presently available hardware technology. A feeder link interface payload was designed, matching the overall system specifications. The TT and C system architecture is shown to be adequate.

  15. The TechSat 21 Autonomous Sciencecraft Experiment

    NASA Technical Reports Server (NTRS)

    Sherwood, Robert; Knight, Russell; Rabideau, Gregg; Chien, Steve; Tran, Daniel; Cichy, Benjamin; Castano, Rebecca; Stough, Timothy; Davies, Ashley

    2004-01-01

    Software has been developed to perform a number of functions essential to autonomous operation in the Autonomous Sciencecraft Experiment (ASE), which is scheduled to be demonstrated aboard a constellation of three spacecraft, denoted TechSat 21, to be launched by the Air Force into orbit around the Earth in January 2006. A prior version of this software was reported in Software for an Autonomous Constellation of Satellites (NPO-30355), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 44. The software includes the following components: Algorithms to analyze image data, generate scientific data products, and detect conditions, features, and events of potential scientific interest; A program that uses component-based computational models of hardware to analyze anomalous situations and to generate novel command sequences, including (when possible) commands to repair components diagnosed as faulty; A robust-execution-management component that uses the Spacecraft Command Language (SCL) software to enable event-driven processing and low-level autonomy; and The Continuous Activity Scheduling, Planning, Execution, and Replanning (CASPER) program for replanning activities, including downlink sessions, on the basis of scientific observations performed during previous orbit cycles.

  16. CryoSat-2 commissioning phase results summary

    NASA Astrophysics Data System (ADS)

    Cullen, R.

    2010-12-01

    CryoSat-2 was launched on 8th April 2010 and following a 3 day LEOP entered its 6 month commissioning phase. The primary payload of the platform consists of the Synthetic Interferometric Radar Altimeter (SIRAL-2) with support for its data processing coming from data acquired from on-board DORIS DGXX and star trackers. We present a description of the payload and provide post-launch performance summaries in terms of SIRAL internal/external calibration in combination with an assessment of global data acquisition achievement in each of the three science modes: Low resolution pulse-width limited mode (LRM) over interior land-ice and ocean to support POD, Synthetic aperture radar mode (SARM) for sea-ice and SAR interferometric mode (SARInM) for higher surface slope land-ice sheet margin acquisitions. Commissioning activities are summarised with examples and we provide conclusions on the experiences gained with the data during this period. Specific issues are highlighted and that Users of the data products should consider taking into account with their analyses. Finally, present performances of the three science modes over transponders and open ocean calibration zones are provided in addition to specific cases over land and sea ice. Preliminary performances of DORIS and star trackers will be provided in the context of overall SIRAL performance.

  17. CryoSat Products and Data Quality Assessment

    NASA Astrophysics Data System (ADS)

    Scagliola, M.; Mannan, R.; Fornari, M.; Bouzinac, C.

    2012-12-01

    The main payload of CryoSat-2 is a Ku band pulse-width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach an along-track resolution of about 250 meters which is a significant improvement over traditional pulse-width limited radar altimeters. There are three operating modes: Low-Resolution mode (LRM), Synthetic Aperture Radar (SAR) and Synthetic Aperture Radar Interferometric (SARIn). Both the Level 1b and the Level 2 data products are defined depending on the operating mode used by the instrument. However, Level 1b products essentially contain an average echo for each location along the ground track while Level 2 products contains an elevation for each location along the satellite track. In this paper we will detail as first the different data products and then the quality achieved on those products will be described after almost two years of operational activity of the Cryosat-2 satellite.

  18. Satisfiability Threshold for Random Regular nae-sat

    NASA Astrophysics Data System (ADS)

    Ding, Jian; Sly, Allan; Sun, Nike

    2016-01-01

    We consider the random regular k- nae- sat problem with n variables, each appearing in exactly d clauses. For all k exceeding an absolute constant {{k}_0}, we establish explicitly the satisfiability threshold {{{d_star} equiv {d_star(k)}}}. We prove that for {{d < d_star}} the problem is satisfiable with high probability, while for {{d > d_star}} the problem is unsatisfiable with high probability. If the threshold {{d_star}} lands exactly on an integer, we show that the problem is satisfiable with probability bounded away from both zero and one. This is the first result to locate the exact satisfiability threshold in a random constraint satisfaction problem exhibiting the condensation phenomenon identified by Krzakała et al. [Proc Natl Acad Sci 104(25):10318-10323, 2007]. Our proof verifies the one-step replica symmetry breaking formalism for this model. We expect our methods to be applicable to a broad range of random constraint satisfaction problems and combinatorial problems on random graphs.

  19. LifeSat engineering in-house vehicle design

    NASA Technical Reports Server (NTRS)

    Adkins, A.; Badhwar, G.; Bryant, L.; Caram, J.; Conley, G.; Crull, T.; Cuthbert, P.; Darcy, E.; Delaune, P.; Edeen, M.

    1992-01-01

    The LifeSat program was initiated to research the effects of microgravity and cosmic radiation on living organisms. The effects of long-term human exposure to free-space radiation fields over a range of gravitational environments has long been recognized as one of the primary design uncertainties for human space exploration. A critical design issue in the radiation biology requirements was the lack of definition of the minimum radiation absorbed dosage required to produce statistically meaningful data. The Phase A study produced a spacecraft conceptual design resembling a Discoverer configuration with a total weight of approximately 2800 pounds that would carry a 525-pound payload module (45 inches in diameter and 36 inches long) and support up to 12 rodents and a general biology module supporting lower life forms for an on-orbit duration of up to 60 days. The phase B conceptual designs focused on gravitational biology requirements and only briefly addressed the design impacts of the shift toward radiobiological science that occurred during the latter half of the Phase B studies.

  20. DebriSat Fragment Characterization System and Processing Status

    NASA Technical Reports Server (NTRS)

    Rivero, M.; Shiotani, B.; M. Carrasquilla; Fitz-Coy, N.; Liou, J. C.; Sorge, M.; Huynh, T.; Opiela, J.; Krisko, P.; Cowardin, H.

    2016-01-01

    The DebriSat project is a continuing effort sponsored by NASA and DoD to update existing break-up models using data obtained from hypervelocity impact tests performed to simulate on-orbit collisions. After the impact tests, a team at the University of Florida has been working to characterize the fragments in terms of their mass, size, shape, color and material content. The focus of the post-impact effort has been the collection of 2 mm and larger fragments resulting from the hypervelocity impact test. To date, in excess of 125K fragments have been recovered which is approximately 40K more than the 85K fragments predicted by the existing models. While the fragment collection activities continue, there has been a transition to the characterization of the recovered fragments. Since the start of the characterization effort, the focus has been on the use of automation to (i) expedite the fragment characterization process and (ii) minimize the effects of human subjectivity on the results; e.g., automated data entry processes were developed and implemented to minimize errors during transcription of the measurement data. At all steps of the process, however, there is human oversight to ensure the integrity of the data. Additionally, repeatability and reproducibility tests have been developed and implemented to ensure that the instrumentations used in the characterization process are accurate and properly calibrated.

  1. Ad hoc CubeSat constellations: Secondary launch coverage and distribution

    NASA Astrophysics Data System (ADS)

    Marinan, A.; Nicholas, A.; Cahoy, K.

    The primary purpose of a constellation is to obtain global measurements with improved spatial and temporal resolution. The small size, low cost, standardized form factor, and increasing availability of commercial parts for CubeSats make them ideal for use in constellations. However, without taking advantage of secondary payload opportunities, it would be costly to launch and distribute a CubeSat constellation into a specific configuration. A cost-effective way to launch a constellation of CubeSats is via consecutive secondary payload launch opportunities, but the resulting constellation would be an ad hoc mix of orbit parameters. We focus on the feasibility of cobbling together constellation-like functionality from multiple secondary payload opportunities. Each participating CubeSat (or set of CubeSats) per launch could have completely different orbital parameters, even without propulsion onboard the CubeSats or intermediate transfer carriers. We look at the ground coverages that could be obtained for a constellation of five to six orbital planes with one to six satellites in each plane. We analyze past and announced future launch opportunities for CubeSats, including launch platforms supported by the NASA Educational Launch of Nanosatellites (ELaNa). We consider combinations of possible launch locations and temporal spacings over the course of one year and simulate the resulting ground coverage patterns and revisit times for an ad hoc constellation using these launch opportunities. We perform this analysis for two separate case studies - one with only US launches and one with both US and non-US opportunities - and vary the number of satellites per orbital plane. Typical CubeSat mission lifetimes and deorbit times for low-altitude orbits are included in these analyses. The ad hoc constellation results are compared to coverage from uniformly-placed LEO constellations and are quantified in terms of revisit time, time to 100% global coverage, and response time. For mu

  2. Invariance of Linkings of the Revised 2005 SAT Reasoning Test™ to the SAT® I: Reasoning Test across Gender Groups. Research Report No. 2005-6. ETS RR-05-17

    ERIC Educational Resources Information Center

    Liu, Jinghua; Feigenbaum, Miriam; Dorans, Neil J.

    2005-01-01

    Score equity assessment was used to evaluate linkings of new SAT® to the current SAT Reasoning Test™. Population invariance across gender groups was studied on the linkage of a new SAT critical reading prototype to a current SAT verbal section, and on the linkage of a new SAT math prototype to a current SAT math section. The results indicated that…

  3. Ten-Year Trends in SAT Scores and Other Characteristics of High School Seniors Taking the SAT and Planning To Study Mathematics, Science, or Engineering. Research Report.

    ERIC Educational Resources Information Center

    Grandy, Jerilee

    This study analyzed data from the Scholastic Aptitude Test (SAT) taken by high school seniors between 1975 and 1986. Its purpose was to study trends in the numbers, test scores, and other characteristics of examinees planning to major in mathematics, science, and engineering, and to compare these data with comparable data from examinees planning…

  4. In female rats, ethylene glycol treatment elevates protein expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) without inducing hyperoxaluria

    PubMed Central

    Breljak, Davorka; Brzica, Hrvoje; Vrhovac, Ivana; Micek, Vedran; Karaica, Dean; Ljubojević, Marija; Sekovanić, Ankica; Jurasović, Jasna; Rašić, Dubravka; Peraica, Maja; Lovrić, Mila; Schnedler, Nina; Henjakovic, Maja; Wegner, Waja; Burckhardt, Gerhard; Burckhardt, Birgitta C.; Sabolić, Ivan

    2015-01-01

    Aim To investigate whether the sex-dependent expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) changes in a rat model of ethylene glycol (EG)-induced hyperoxaluria. Methods Rats were given tap water (12 males and 12 females; controls) or EG (12 males and 12 females; 0.75% v/v in tap water) for one month. Oxaluric state was confirmed by biochemical parameters in blood plasma, urine, and tissues. Expression of sat-1 and rate-limiting enzymes of oxalate synthesis, alcohol dehydrogenase 1 (Adh1) and hydroxy-acid oxidase 1 (Hao1), was determined by immunocytochemistry (protein) and/or real time reverse transcription polymerase chain reaction (mRNA). Results EG-treated males had significantly higher (in μmol/L; mean ± standard deviation) plasma (59.7 ± 27.2 vs 12.9 ± 4.1, P < 0.001) and urine (3716 ± 1726 vs 241 ± 204, P < 0.001) oxalate levels, and more abundant oxalate crystaluria than controls, while the liver and kidney sat-1 protein and mRNA expression did not differ significantly between these groups. EG-treated females, in comparison with controls had significantly higher (in μmol/L) serum oxalate levels (18.8 ± 2.9 vs 11.6 ± 4.9, P < 0.001), unchanged urine oxalate levels, low oxalate crystaluria, and significantly higher expression (in relative fluorescence units) of the liver (1.59 ± 0.61 vs 0.56 ± 0.39, P = 0.006) and kidney (1.77 ± 0.42 vs 0.69 ± 0.27, P < 0.001) sat-1 protein, but not mRNA. The mRNA expression of Adh1 was female-dominant and that of Hao1 male-dominant, but both were unaffected by EG treatment. Conclusions An increased expression of hepatic and renal oxalate transporting protein sat-1 in EG-treated female rats could protect from hyperoxaluria and oxalate urolithiasis. PMID:26526882

  5. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterization

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Fitz-Coy, N.; Werremeyer, M.; Huynh, T.; Voelker, M.; Opiela, J.

    2012-01-01

    DebriSat is a planned laboratory ]based satellite hypervelocity impact experiment. The goal of the project is to characterize the orbital debris that would be generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 's US Navy Transit satellite. There are three phases to this project: the design and fabrication of an engineering model representing a modern, 50-cm/50-kg class LEO satellite known as DebriSat; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area ]to ]mass ratio, density, shape, material composition, optical properties, and radar cross ]section distributions, will be used to supplement the DoD fs and NASA fs satellite breakup models to better describe the breakup outcome of a modern satellite. Updated breakup models will improve mission planning, environmental models, and event response. The DebriSat project is sponsored by the Air Force fs Space and Missile Systems Center and the NASA Orbital Debris Program Office. The design and fabrication of DebriSat is led by University of Florida with subject matter experts f support from The Aerospace Corporation. The major milestones of the project include the complete fabrication of DebriSat by September 2013, the hypervelocity impact of DebriSat at the Air Force fs Arnold Engineering Development Complex in early 2014, and fragment characterization and data analyses in late 2014.

  6. Investigating the Efficacy of CubeSats for Asteroid Detection

    NASA Technical Reports Server (NTRS)

    O'Toole, Conor

    2015-01-01

    A simulation to examine the potential of a network of CubeSats for detecting Near Earth Objects is discussed, in terms of goals, methods used and initial results obtained. By designing a basic optical system and the orbital parameters of the satellites in this network, their effectiveness for detecting asteroids is examined, with a small sample of cataloged asteroids considered.The conditions to be satisfied for detection cover both the geometrical aspects of astronomy such as field of view and line of sight, along with more technical optics-based conditions such as resolution and sensitivity of our telescopes. Of special interest to us in this work is the region of the sky between 45 deg. and 90 deg. from the Sun, as seen from the Earth. This part of the sky is currently unobservable by ground-based surveys and so provides the primary reason to consider a space-based one. There exist a number of issues with the simulation which call these results into question, but an eort has been made to remove those results which exceed the possible capabilities of the satellite network, and identify those aspects of the mission which should be examined in order to provide an in-depth assessment of it's performance. With these filters applied to the overall data, a tentative result of 1458 total detections over an 85 year period has been obtained, with 14 of the 22 asteroids in the sample being detected at least once. A number of ways in which the simulation could be improved are also proposed, both in-terms of addressing the aforementioned issues, as well as how to improve on the accuracy of the simulation and capture as many aspects of a space-based optical astronomy mission as possible,with the possible nal form of the simulation being a tool for assessing the performance of any space-based optical mission to detect asteroids.

  7. Absolute calibration of the EnviSat-1 radar altimeter

    NASA Astrophysics Data System (ADS)

    Roca, Monica; Francis, Richard

    1998-12-01

    The EnviSat-1 satellite will embark an innovative radar altimeter. The calibration of the measurements of range from this instrument will be performed using novel techniques. The range measurement will be calibrated absolutely by establishing the actual geocentric sea-level along the sub- satellite tracks. These tracks are located in a limited and well-controlled region in the western Mediterranean and will include a number of fully-equipped individual sites which will provide higher confidence in the overall analysis, combined with data from the whole area at lower weight. The determination of the geocentric sea-level is performed using tide gauges and geodetic means such as leveling and floating GPS receivers. The altimeter sea-level is derived from the altimeter range corrected for propagation effects and sea- state bias, and a precise restitution of the trajectory of the satellite. These measurements comprise three vectors: range, orbital height and sea-surface height. The difference between orbital-height minus range, and sea-surface height provides the bias. The backscatter coefficient measured by previous altimeters has not been absolutely calibrated. An emerging application of the RA-2 in investigation of surface properties has identified the need to perform this calibration. A number of techniques are under study to determine the feasibility of meeting this need, including the use of well-controlled natural targets, the use of the altimeter receiver as a passive radiometer in order to determine its gain and the use of a transponder to return a precisely known return echo power to the radar.

  8. The Social Attribution Task-Multiple Choice (SAT-MC): A Psychometric and Equivalence Study of an Alternate Form.

    PubMed

    Johannesen, Jason K; Lurie, Jessica B; Fiszdon, Joanna M; Bell, Morris D

    2013-01-01

    The Social Attribution Task-Multiple Choice (SAT-MC) uses a 64-second video of geometric shapes set in motion to portray themes of social relatedness and intentions. Considered a test of "Theory of Mind," the SAT-MC assesses implicit social attribution formation while reducing verbal and basic cognitive demands required of other common measures. We present a comparability analysis of the SAT-MC and the new SAT-MC-II, an alternate form created for repeat testing, in a university sample (n = 92). Score distributions and patterns of association with external validation measures were nearly identical between the two forms, with convergent and discriminant validity supported by association with affect recognition ability and lack of association with basic visual reasoning. Internal consistency of the SAT-MC-II was superior (alpha = .81) to the SAT-MC (alpha = .56). Results support the use of SAT-MC and new SAT-MC-II as equivalent test forms. Demonstrating relatively higher association to social cognitive than basic cognitive abilities, the SAT-MC may provide enhanced sensitivity as an outcome measure of social cognitive intervention trials.

  9. Assessing the format of the presentation of text in developing a Reading Strategy Assessment Tool (R-SAT).

    PubMed

    Gilliam, Sara; Magliano, Joseph P; Millis, Keith K; Levinstein, Irwin; Boonthum, Chutima

    2007-05-01

    We are constructing a new computerized test of reading comprehension called the Reading Strategy Assessment Tool (R-SAT). R-SAT elicits and analyzes verbal protocols that readers generate in response to questions as they read texts. We examined whether the amount of information available to the reader when reading and answering questions influenced the extent to which R-SAT accounts for comprehension. We found that R-SAT was most predictive of comprehension when the readers did not have access to the text as they answered questions.

  10. Integrated monitoring technologies for the management of a Soil-Aquifer-Treatment (SAT) system

    NASA Astrophysics Data System (ADS)

    Kallioras, Andreas; Kofakis, Petros; Bumberger, Jan; Athanasiou, Georgios; Schimdt, Felix; Apostolopoulos, Georgios; Uzunoglou, Nikolaos; Dietrich, Peter; Schuth, Christoph

    2015-04-01

    Artificial recharge of groundwater has an important role to play in water reuse as treated wastewater effluent can be infiltrated into the ground for aquifer recharge. As the effluent moves through the soil and the aquifer, it undergoes significant quality improvements through physical, chemical, and biological processes in the underground environment. Collectively, these processes and the water quality improvement obtained are called soil-aquifer-treatment (SAT) or geopurification. The pilot site of Lavrion Technological & Cultural Park (LTCP) of the National Technical University of Athens (NTUA), involves the employment of plot infiltration basins at experimental scale, which will be using waters of impaired quality as a recharge source, and hence acting as a Soil-Aquifer-Treatment, SAT, system. Τhe LTCP site will be employed as a pilot SAT system complemented by new technological developments, which will be providing continuous monitoring of the quantitative and qualitative characteristics of infiltrating groundwater through all hydrologic zones (i.e. surface, unsaturated and saturated zone). This will be achieved by the development and installation of an integrated system of prototype sensing technologies, installed on-site, and offering a continuous evaluation of the performance of the SAT system. An integrated approach of the performance evaluation of any operating SAT system should aim at parallel monitoring of all hydrologic zones, proving the sustainability of all involved water quality treatment processes within unsaturated and saturated zone. Hence a prototype system of Time and Frequency Domain Reflectometry (TDR & FDR) sensors is developed and will be installed, in order to achieve continuous quantitative monitoring of the unsaturated zone through the entire soil column down to significant depths below the SAT basin. Additionally, the system contains two different radar-based sensing systems that will be offering (i) identification of preferential

  11. PlumeSat: A Micro-Satellite Based Plume Imagery Collection Experiment

    SciTech Connect

    Ledebuhr, A.G.; Ng, L.C.

    2002-06-30

    This paper describes a technical approach to cost-effectively collect plume imagery of boosting targets using a novel micro-satellite based platform operating in low earth orbit (LEO). The plume collection Micro-satellite or PlueSat for short, will be capable of carrying an array of multi-spectral (UV through LWIR) passive and active (Imaging LADAR) sensors and maneuvering with a lateral divert propulsion system to different observation altitudes (100 to 300 km) and different closing geometries to achieve a range of aspect angles (15 to 60 degrees) in order to simulate a variety of boost phase intercept missions. The PlumeSat will be a cost effective platform to collect boost phase plume imagery from within 1 to 10 km ranges, resulting in 0.1 to 1 meter resolution imagery of a variety of potential target missiles with a goal of demonstrating reliable plume-to-hardbody handover algorithms for future boost phase intercept missions. Once deployed on orbit, the PlumeSat would perform a series phenomenology collection experiments until expends its on-board propellants. The baseline PlumeSat concept is sized to provide from 5 to 7 separate fly by data collects of boosting targets. The total number of data collects will depend on the orbital basing altitude and the accuracy in delivering the boosting target vehicle to the nominal PlumeSat fly-by volume.

  12. From laboratory plasma experiments to space plasma experiments with `CubeSat' nano-satellites

    NASA Astrophysics Data System (ADS)

    Charles, Christine

    2016-09-01

    `CubeSat' nano-satellites provide low-cost access to space. SP3 laboratory's involvement in the European Union `QB50' `CubeSat' project [www.qb50.eu] which will launch into space 50 `CubeSats' from 27 Countries to study the ionosphere and the lower thermosphere will be presented. The Chi Kung laboratory plasma experiment and the Helicon Double Layer Thruster prototype can be tailored to investigate expanding magnetized plasma physics relevant to space physics (solar corona, Earth's aurora, adiabatic expansion and polytropic studies). Chi Kung is also used as a plasma wind tunnel for ground-based calibration of the University College London QB50 Ion Neutral Mass Spectrometer. Space qualification of the three Australian QB50 `CubeSats' (June 2016) is carried out in the WOMBAT XL space simulation chamber. The QB50 satellites have attitude control but altitude control is not a requirement. SP3 is developing end-to-end miniaturised radiofrequency plasma propulsion systems (such as the Pocket Rocket and the MiniHel thrusters with power and propellant sub-systems) for future `CubeSat' missions.

  13. Building the future of WaferSat spacecraft for relativistic spacecraft

    NASA Astrophysics Data System (ADS)

    Brashears, Travis; Lubin, Philip; Rupert, Nic; Stanton, Eric; Mehta, Amal; Knowles, Patrick; Hughes, Gary B.

    2016-09-01

    Recently, there has been a dramatic change in the way space missions are viewed. Large spacecraft with massive propellant-filled launch stages have dominated the space industry since the 1960's, but low-mass CubeSats and low-cost rockets have enabled a new approach to space exploration. In recent work, we have built upon the idea of extremely low mass (sub 1 kg), propellant-less spacecraft that are accelerated by photon propulsion from dedicated directed-energy facilities. Advanced photonics on a chip with hybridized electronics can be used to implement a laser-based communication system on board a sub 1U spacecraft that we call a WaferSat. WaferSat spacecraft are equipped with reflective sails suitable for propulsion by directed-energy beams. This low-mass spacecraft design does not require onboard propellant, creating significant new opportunities for deep space exploration at a very low cost. In this paper, we describe the design of a prototype WaferSat spacecraft, constructed on a printed circuit board. The prototype is envisioned as a step toward a design that could be launched on an early mission into Low Earth Orbit (LEO), as a key milestone in the roadmap to interstellar flight. In addition to laser communication, the WaferSat prototype includes subsystems for power source, attitude control, digital image acquisition, and inter-system communications.

  14. General Aviation in Nebraska: Nebraska SATS Project Background Paper No. 1

    NASA Technical Reports Server (NTRS)

    Smith, Russell; Wachal, Jocelyn

    2000-01-01

    The Nebraska SATS project is a state-level component of NASA's Small Aircraft Transportation System (SATS). During the next several years the project will examine several different factors affecting SATS implementation in Nebraska. These include economic and taxation issues, public policy issues, airport planning processes, information dissemination strategies, and systemic change factors. This background paper profiles the general aviation system in Nebraska. It is written to provide information about the "context" within which SATS will be pursued. The primary focus is thus on describing and providing background information about the current situation. A secondary focus is on drawing general conclusions about the ability of the current system to incorporate the types of changes implied by SATS. First, some brief information on the U.S. aviation system is provided. The next two sections profile the current general aviation aircraft and pilot base. Nebraska's system of general aviation airports is then described. Within this section of the paper, information is provided on the different types of general aviation airports in Nebraska, airport activity levels and current infrastructure. The fourth major section of the background paper looks at Nebraska's local airport authorities. These special purpose local governments oversee the majority of the general aviation airports in the state. Among the items examined are total expenditures, capital expenditures and planning activities. Next, the paper provides background information on the Nebraska Department of Aeronautics (NDA) and recent Federal funding for general aviation in Nebraska. The final section presents summary conclusions.

  15. Urano y sus dos satélites irregulares recientemente descubiertos

    NASA Astrophysics Data System (ADS)

    Parisi, M. G.; Brunini, A.

    Hasta hace poco tiempo, Urano era el único de los Planetas Gigantes que no poseía satélites irregulares. Esto lo diferenciaba del resto de los planetas Gigantes, al igual que la peculiar oblicuidad de su eje de spin. La gran inclinación de su eje de rotación se debe probablemente a una colisión que sufrió el planeta con otro embrión planetario al final del proceso de formación. Esta colisión habría desligado satélites exteriores preexistentes del planeta. Recientemente se han descubierto dos satélites irregulares de Urano, lo que introduce algunas nuevas cotas y condiciones en el escenario de la "Hipótesis de la Gran Colisión" . Los satélites irregulares de Urano tuvieron que ser capturados en una etapa posterior a la del escenario de la Gran Colisión, de no ser así, hubieran sido eyectados del sistema por el impulso impartido con ese gran impacto. En este trabajo, se discuten los posibles mecanismos de captura de los satélites irregulares y se presenta un nuevo posible mecanismo para dicha captura.

  16. Genetic parameters of saturated and monounsaturated fatty acid content and the ratio of saturated to unsaturated fatty acids in bovine milk.

    PubMed

    Soyeurt, H; Dardenne, P; Dehareng, F; Bastin, C; Gengler, N

    2008-09-01

    Fatty acid composition influences the nutritional quality of milk and the technological properties of butter. Using a prediction of fatty acid (FA) contents by mid-infrared (MIR) spectrometry, a large amount of data concerning the FA profile in bovine milk was collected. The large number of records permitted consideration of more complex models than those used in previous studies. The aim of the current study was to estimate the effects of season and stage of lactation as well as genetic parameters of saturated (SAT) and monounsaturated (MONO) fatty acid contents in bovine milk and milk fat, and the ratio of SAT to unsaturated fatty acids (UNSAT) that reflect the hardness of butter (SAT:UNSAT), using 7 multiple-trait, random-regression test-day models. The relationship between these FA traits with common production traits was also studied. The data set contained 100,841 test-day records of 11,626 Holstein primiparous cows. The seasonal effect was studied based on unadjusted means. These results confirmed that milk fat produced during spring and summer had greater UNSAT content compared with winter (63.13 vs. 68.94% of SAT in fat, on average). The effect of stage of lactation on FA profile was studied using the same methodology. Holstein cows in early first lactation produced a lower content of SAT in their milk fat. Variance components were estimated using a Bayesian method via Gibbs sampling. Heritability of SAT in milk (0.42) was greater than heritability of SAT in milk fat (0.24). Estimates of heritability for MONO were also different in milk and fat (0.14 vs. 0.27). Heritability of SAT:UNSAT was moderate (0.27). For all of these traits, the heritability estimates and the genetic and phenotypic correlations varied through the lactation.

  17. Integrating BalloonSAT and Atmospheric Dynamic Concepts into the Secondary Classroom

    NASA Astrophysics Data System (ADS)

    Fong, B. N.; Kennon, J. T.; Roberts, E.

    2016-05-01

    Arkansas BalloonSAT is an educational outreach and scientific research program that is part of Arkansas State University in Jonesboro, AR. The following is a unit of instruction to incorporate BalloonSAT measurements into secondary science classes. Students interpret graphs and identify several atmospheric trends and properties of a typical balloon flight. Students engage critical thinking skills in developing and answering their own questions relevant to the BalloonSAT program. Prerequisite concepts students should know are how to interpret graphs and unit conversions. Students should have a basic understanding of gravity, units of temperature and distance, and error in measurements. The unit is designed for one week after end-of-course exams and before the end of school. The unit may take two to five 50-minute periods, depending on how many activities are completed.

  18. Coastal sea level from inland CryoSat-2 interferometric SAR altimetry

    NASA Astrophysics Data System (ADS)

    Abulaitijiang, Adili; Andersen, Ole Baltazar; Stenseng, Lars

    2015-03-01

    The European Space Agency's CryoSat-2 satellite can operate in a novel synthetic aperture radar interferometric (SARIn) mode where its nominal footprint (swath) is observed by two antennas and the phase difference between the signals is used to determination the exact location of the scatterer through an off-nadir correction. The potential of SARIn for sea level determination is investigated over the fjords of Eastern Greenland. In principle the satellite should only track sea level within its nominal footprint of 7 km across track, but we observe that scattering targets (fjords) within twice its nominal footprint are frequently observed but mislocated in CryoSat-2 due to phase wrapping. We devised a way to relocate the observations and correct the range accordingly. When CryoSat-2 is flying inland we consequently observed that the satellite occasionally provide valid sea level in fjords up to 13 km away in the across-track direction.

  19. Greenland 2012 melt event effects on CryoSat-2 radar altimetry

    NASA Astrophysics Data System (ADS)

    Nilsson, Johan; Vallelonga, Paul; Simonsen, Sebastian B.; Sørensen, Louise Sandberg; Forsberg, René; Dahl-Jensen, Dorthe; Hirabayashi, Motohiro; Goto-Azuma, Kumiko; Hvidberg, Christine S.; Kjær, Helle A.; Satow, Kazuhide

    2015-05-01

    CryoSat-2 data are used to study elevation changes over an area in the interior part of the Greenland Ice Sheet during the extreme melt event in July 2012. The penetration of the radar signal into dry snow depends heavily on the snow stratigraphy, and the rapid formation of refrozen ice layers can bias the surface elevations obtained from radar altimetry. We investigate the change in CryoSat-2 waveforms and elevation estimates over the melt event and interpret the findings by comparing in situ surface and snow pit observations from the North Greenland Eemian Ice Drilling Project camp. The investigation shows a major transition of scattering properties around the area, and an apparent elevation increase of 56 ± 26 cm is observed in reprocessed CryoSat-2 data. We suggest that this jump in elevation can be explained by the formation of a refrozen melt layer that raised the reflective surface, introducing a positive elevation bias.

  20. The Iodine Satellite (iSat) Project Development Towards Critical Design Review (CDR)

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.; Selby, Michael; Polzin, Kurt A.; Kamhawi, Hani; Hickman, Tyler; Byrne, Larry

    2016-01-01

    Despite the prevalence of Small Satellites in recent years, the systems flown to date have very limited propulsion capability. SmallSats are typically secondary payloads and have significant constraints for volume, mass, and power in addition to limitations on the use of hazardous propellants or stored energy (i.e. high pressure vessels). These constraints limit the options for SmallSat maneuverability. NASA's Space Technology Mission Directorate approved the iodine Satellite flight project for a rapid demonstration of iodine Hall thruster technology in a 12U configuration under the Small Spacecraft Technology Program. The project formally began in FY15 as a partnership between NASA MSFC, NASA GRC, and Busek Co, Inc., with the Air Force supporting the propulsion technology maturation. The team is in final preparation of the Critical Design Review prior to initiating the fabrication and integration phase of the project. The iSat project is on schedule for a launch opportunity in November 2017.

  1. The Iodine Satellite (iSat) Project Development Towards Critical Design Review

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.; Calvert, Derek; Kamhawi, Hani; Hickman, Tyler; Szabo, James; Byrne, Lawrence

    2015-01-01

    Despite the prevalence of small satellites in recent years, the systems flown to date have very limited propulsion capability. SmallSats are typically secondary payloads and have significant constraints for volume, mass, and power in addition to limitations on the use of hazardous propellants or stored energy. These constraints limit the options for SmallSat maneuverability. NASA's Space Technology Mission Directorate approved the iodine Satellite flight project for a rapid demonstration of iodine Hall thruster technology in a 12U (cubesat units) configuration under the Small Spacecraft Technology Program. The mission is a partnership between NASA MSFC, NASA GRC, and Busek Co, Inc., with the Air Force supporting the propulsion technology maturation. The team is working towards the critical design review in the final design and fabrication phase of the project. The current design shows positive technical performance margins in all areas. The iSat project is planned for launch readiness in the spring of 2017.

  2. A variable neighborhood Walksat-based algorithm for MAX-SAT problems.

    PubMed

    Bouhmala, Noureddine

    2014-01-01

    The simplicity of the maximum satisfiability problem (MAX-SAT) combined with its applicability in many areas of artificial intelligence and computing science made it one of the fundamental optimization problems. This NP-complete problem refers to the task of finding a variable assignment that satisfies the maximum number of clauses (or the sum of weights of satisfied clauses) in a Boolean formula. The Walksat algorithm is considered to be the main skeleton underlying almost all local search algorithms for MAX-SAT. Most local search algorithms including Walksat rely on the 1-flip neighborhood structure. This paper introduces a variable neighborhood walksat-based algorithm. The neighborhood structure can be combined easily using any local search algorithm. Its effectiveness is compared with existing algorithms using 1-flip neighborhood structure and solvers such as CCLS and Optimax from the eighth MAX-SAT evaluation.

  3. WebSat ‐ A web software for microsatellite marker development

    PubMed Central

    Martins, Wellington Santos; Soares Lucas, Divino César; de Souza Neves, Kelligton Fabricio; Bertioli, David John

    2009-01-01

    Simple sequence repeats (SSR), also known as microsatellites, have been extensively used as molecular markers due to their abundance and high degree of polymorphism. We have developed a simple to use web software, called WebSat, for microsatellite molecular marker prediction and development. WebSat is accessible through the Internet, requiring no program installation. Although a web solution, it makes use of Ajax techniques, providing a rich, responsive user interface. WebSat allows the submission of sequences, visualization of microsatellites and the design of primers suitable for their amplification. The program allows full control of parameters and the easy export of the resulting data, thus facilitating the development of microsatellite markers. Availability The web tool may be accessed at http://purl.oclc.org/NET/websat/ PMID:19255650

  4. CloudSat First Image of a Warm Front Storm Over the Norwegian Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1

    CloudSat's first image, of a warm front storm over the Norwegian Sea, was obtained on May 20, 2006. In this horizontal cross-section of clouds, warm air is seen rising over colder air as the satellite travels from right to left. The red colors are indicative of highly reflective particles such as water droplets (or rain) or larger ice crystals (or snow), while the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudSat Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The blue line below the Cloud Profiling Radar image indicates that the data were taken over water. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) infrared image taken at nearly the same time.

  5. CHARM: A CubeSat Water Vapor Radiometer for Earth Science

    NASA Technical Reports Server (NTRS)

    Lim, Boon; Mauro, David; DeRosee, Rodolphe; Sorgenfrei, Matthew; Vance, Steve

    2012-01-01

    The Jet Propulsion Laboratory (JPL) and Ames Research Center (ARC) are partnering in the CubeSat Hydrometric Atmospheric Radiometer Mission (CHARM), a water vapor radiometer integrated on a 3U CubeSat platform, selected for implementation under NASA Hands-On Project Experience (HOPE-3). CHARM will measure 4 channels at 183 GHz water vapor line, subsets of measurements currently performed by larger and more costly spacecraft (e.g. ATMS, AMSU-B and SSMI/S). While flying a payload that supports SMD science objectives, CHARM provides a hands-on opportunity to develop technical, leadership, and project skills. CHARM will furthermore advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and the CubeSat 183 GHz radiometer system from TRL 4 to TRL 7.

  6. Fine Ice Sheet margins topography from swath processing of CryoSat SARIn mode data

    NASA Astrophysics Data System (ADS)

    Gourmelen, N.; Escorihuela, M. J.; Shepherd, A.; Foresta, L.; Muir, A.; Briggs, K.; Hogg, A. E.; Roca, M.; Baker, S.; Drinkwater, M. R.

    2014-12-01

    Reference and repeat-observations of Glacier and Ice Sheet Margin (GISM) topography are critical to identify changes in ice thickness, provide estimates of mass gain or loss and thus quantify the contribution of the cryosphere to sea level change. The lack of such sustained observations was identified in the Integrated Global Observing Strategy (IGOS) Cryosphere Theme Report as a major shortcoming. Conventional altimetry measurements over GISMs exist, but coverage has been sparse and characterized by coarse ground resolution. Additionally, and more importantly, they proved ineffective in the presence of steep slopes, a typical feature of GISM areas. Since the majority of Antarctic and Greenland ice sheet mass loss is estimated to lie within 100 km from the coast, but only about 10% is surveyed, there is the need for more robust and dense observations of GISMs, in both time and space. The ESA Altimetry mission CryoSat aims at gaining better insight into the evolution of the Cryosphere. CryoSat's revolutionary design features a Synthetic Interferometric Radar Altimeter (SIRAL), with two antennas for interferometry. The corresponding SAR Interferometer (SARIn) mode of operation increases spatial resolution while resolving the angular origin of off-nadir echoes occurring over sloping terrain. The SARIn mode is activated over GISMs and the elevation for the Point Of Closest Approach (POCA) is a standard product of the CryoSat mission. Here we present an approach for more comprehensively exploiting the SARIn mode of CryoSat and produce an ice elevation product with enhanced spatial resolution compared to standard CryoSat-2 height products. In this so called L2-swath processing approach, the full CryoSat waveform is exploited under specific conditions of signal and surface characteristics. We will present the rationale, validation exercises and preliminary results from the Eurpean Space Agency's STSE CryoTop study over selected test regions of the margins of the Greenland

  7. Integration of CubeSat Systems with Europa Surface Exploration Missions

    NASA Astrophysics Data System (ADS)

    Erdoǧan, Enes; Inalhan, Gokhan; Kemal Üre, Nazım

    2016-07-01

    Recent studies show that there is a high probability that a liquid ocean exists under thick icy surface of Jupiter's Moon Europa. The findings also show that Europa has features that are similar to Earth, such as geological activities. As a result of these studies, Europa has promising environment of being habitable and currently there are many missions in both planning and execution level that target Europa. However, these missions usually involve extremely high budgets over extended periods of time. The objective of this talk is to argue that the mission costs can be reduced significantly by integrating CubeSat systems within Europa exploration missions. In particular, we introduce an integrated CubeSat-micro probe system, which can be used for measuring the size and depth of the hypothetical liquid ocean under the icy surface of Europa. The systems consist of an entry module that houses a CubeSat combined with driller measurement probes. Driller measurement probes deploy before the system hits the surface and penetrate the surface layers of Europa. Moreover, a micro laser probe could be used to examine the layers. This process enables investigation of the properties of the icy layer and the environment beneath the surface. Through examination of different scenarios and cost analysis of the components, we show that the proposed CubeSat systems has a significant potential to reduce the cost of the overall mission. Both subsystem requirements and launch prices of CubeSats are dramatically cheaper than currently used satellites. In addition, multiple CubeSats may be used to dominate wider area in space and they are expandable in face of potential failures. In this talk we discuss both the mission design and cost reduction aspects.

  8. A CubeSat to Search for Transiting Planets Around the Young Star Beta Pictoris

    NASA Astrophysics Data System (ADS)

    Blake, Ameer; Roberge, Aki

    2016-01-01

    The goal of this project is to further our growing knowledge of exoplanets in the solar neighborhood. The nearby star Beta Pictoris, which is nearly twice the mass of the Sun, is encircled by a huge disk of dust and gas reaching out 500-800 AU from the star. This so-called "debris disk" is the product of collisions between large numbers of asteroids and comets orbiting this relatively young star. The presence of these small planetary bodies hinted that there might be planets in the disk as well, which was recently confirmed when a ground-based telescope directly imaged a super-Jupiter exoplanet orbiting the star.The debris disk of Beta Pic tells us that this planetary system is edge-on from our vantage point on Earth. Therefore, it is an ideal system to use transit photometry to search for additional planets. We hope to due so by monitoring the brightness of the star over a given period, using a telescope on small satellite (a CubeSat). A CubeSat is a very small satellite tasked with a single purpose and, in this case, a single target. The advantage of a CubeSat over a larger telescope is the low cost and fast development schedule. Since we wish to study only one star's system, a CubeSat is an economical choice, although the limited lifetime of a CubeSat means that only planets with relatively short (up to few month) periods may be found. Our preliminary calculations show that, in principle, we can discover planets from Jupiter-size down to Neptune-size around Beta Pic with a telescope sized to fit in a CubeSat.

  9. SAT2 foot-and-mouth disease virus (FMDV) structurally modified for increased thermostability.

    PubMed

    Scott, Katherine A; Kotecha, Abhay; Seago, Julian; Ren, Jingshan; Fry, Elizabeth E; Stuart, David I; Charleston, Bryan; Maree, Francois F

    2017-03-15

    Foot-and-mouth disease virus (FMDV) is notoriously unstable, particularly the O and SAT serotypes. Consequently, vaccines derived from heat-labile SAT viruses have been linked to the induction of poor duration immunity and hence require more frequent vaccinations to ensure protection. In-silico calculations predicted residue substitutions that would increase interactions at the inter-pentameric interface supporting increased stability. We assessed the stability of the 18 recombinant mutant viruses for their growth kinetics; antigenicity; plaque morphology; genetic stability; temperature, ionic and pH stability using the thermofluor and inactivation assays, in order to evaluate potential SAT2 vaccine candidates with improved stability. The most stable mutation was the single mutant S2093Y for temperature and pH stability, whilst other promising single mutants were E3198A, L2094V,S2093H and the triple mutant F2062Y-H2087M-H3143V. Although the S2093Y mutant had the greatest stability it exhibited smaller plaques; a reduced growth rate; a change in a monoclonal antibody footprint, and poor genetic stability properties compared to the wild-type virus. However, these factors affecting production can be overcome. The addition of 1M NaCl salt was found to further increase the stability of the SAT2 panel of viruses. The S2093Y and S2093H mutants were selected for future use in stabilising SAT2 vaccines.IMPORTANCE Foot-and-mouth disease virus (FMDV) causes a highly contagious acute vesicular disease in cloven-hoofed livestock and wildlife. The control of the disease by vaccination is essential, especially at livestock-wildlife interfaces. The instability of serotypes such as SAT2 affects the quality of the vaccine and therefore the duration of immunity. We have shown that by mutating residues at the capsid interface through predictive modelling we can improve the stability of SAT2 viruses. This is an important finding for the potential use of such mutants in improving the

  10. Integrated monitoring technologies for the management of a Soil-Aquifer-Treatment (SAT) system.

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Alexandros; Kallioras, Andreas; Kofakis, Petros; Bumberger, Jan; Schmidt, Felix; Athanasiou, Georgios; Uzunoglou, Nikolaos; Amditis, Angelos; Dietrich, Peter

    2016-04-01

    Artificial recharge of groundwater has an important role to play in water reuse as treated wastewater effluent can be infiltrated into the ground for aquifer recharge. As the effluent moves through the soil and the aquifer, it undergoes significant quality improvements through physical, chemical, and biological processes in the underground environment. Collectively, these processes and the water quality improvement obtained are called soil-aquifer-treatment (SAT) or geopurification. The pilot site of Lavrion Technological & Cultural Park (LTCP) of the National Technical University of Athens (NTUA), involves the employment of plot infiltration basins at experimental scale, which will be using waters of impaired quality as a recharge source, and hence acting as a Soil-Aquifer-Treatment, SAT, system. Τhe LTCP site will be employed as a pilot SAT system complemented by new technological developments, which will be providing continuous monitoring of the quantitative and qualitative characteristics of infiltrating groundwater through all hydrologic zones (i.e. surface, unsaturated and saturated zone). This will be achieved by the development and installation of an integrated system of prototype sensing technologies, installed on-site, and offering a continuous evaluation of the performance of the SAT system. An integrated approach of the performance evaluation of any operating SAT system should aim at parallel monitoring of all hydrologic zones, proving the sustainability of all involved water quality treatment processes within unsaturated and saturated zone. Hence a prototype system of Time and Frequency Domain Reflectometry (TDR & FDR) sensors is developed and will be installed, in order to achieve continuous quantitative monitoring of the unsaturated zone through the entire soil column down to significant depths below the SAT basin. Additionally, the system contains two different radar-based sensing systems that will be offering (i) identification of preferential

  11. The QBito CubeSat: Applications in Space Engineering Education at Technical University of Madrid

    NASA Astrophysics Data System (ADS)

    Fernandez Fraile, Jose Javier; Laverón-Simavilla, Ana; Calvo, Daniel; Moreno Benavides, Efren

    The QBito CubeSat is one of the 50 CubeSats that is being developed for the QB50 project. The project is funded by the 7 (th) Frame Program to launch 50 CubeSats in a ‘string-of-pearls’ configuration for multi-point, in-situ measurements in the lower thermosphere and re-entry research. The 50 CubeSats, developed by an international network of universities and research institutions, will comprise 40 double CubeSats with atmospheric sensors and 10 double or triple CubeSats for science and technology demonstration. It will be the first large-scale CubeSat constellation in orbit; a concept that has been under discussion for several years but not implemented up to now. This project has a high educational interest for universities; beyond the scientific and technological results, being part of an international group of over 90 universities all over the world working and sharing knowledge to achieve a successful mission represents an exciting opportunity. The QBito project main educational motivation is to educate students in space technologies and in space systems engineering. The Universidad Politécnica de Madrid (UPM) is designing, developing, building and testing one of the double CubeSats carrying as payload a kit of atmospheric sensors from the consortium, and other payloads developed by the team such as an IR non-refrigerated sensor, a Phase Change Material (PCM) for thermal control applications, a Fuzzy Logic Attitude Control System and other technological developments such as an optimized antenna deployment mechanism, a lightweight multi-mission configurable structure, and an efficient Electric Power System (EPS) with a Maximum Peak Power Tracker (MPPT). This project has been integrated in the training of the Aerospatiale Engineering, Master and PhD degree students by involving them in the complete engineering process, from its conceptual design to the post-flight conclusions. Three subsystems have been selected for being developed from the conceptual design

  12. Assimilation of CryoSat-2 altimetry to a hydrodynamic model of the Brahmaputra river

    NASA Astrophysics Data System (ADS)

    Schneider, Raphael; Nygaard Godiksen, Peter; Ridler, Marc-Etienne; Madsen, Henrik; Bauer-Gottwein, Peter

    2016-04-01

    Remote sensing provides valuable data for parameterization and updating of hydrological models, for example water level measurements of inland water bodies from satellite radar altimeters. Satellite altimetry data from repeat-orbit missions such as Envisat, ERS or Jason has been used in many studies, also synthetic wide-swath altimetry data as expected from the SWOT mission. This study is one of the first hydrologic applications of altimetry data from a drifting orbit satellite mission, namely CryoSat-2. CryoSat-2 is equipped with the SIRAL instrument, a new type of radar altimeter similar to SRAL on Sentinel-3. CryoSat-2 SARIn level 2 data is used to improve a 1D hydrodynamic model of the Brahmaputra river basin in South Asia set up in the DHI MIKE 11 software. CryoSat-2 water levels were extracted over river masks derived from Landsat imagery. After discharge calibration, simulated water levels were fitted to the CryoSat-2 data along the Assam valley by adapting cross section shapes and datums. The resulting hydrodynamic model shows accurate spatio-temporal representation of water levels, which is a prerequisite for real-time model updating by assimilation of CryoSat-2 altimetry or multi-mission data in general. For this task, a data assimilation framework has been developed and linked with the MIKE 11 model. It is a flexible framework that can assimilate water level data which are arbitrarily distributed in time and space. Different types of error models, data assimilation methods, etc. can easily be used and tested. Furthermore, it is not only possible to update the water level of the hydrodynamic model, but also the states of the rainfall-runoff models providing the forcing of the hydrodynamic model. The setup has been used to assimilate CryoSat-2 observations over the Assam valley for the years 2010 to 2013. Different data assimilation methods and localizations were tested, together with different model error representations. Furthermore, the impact of

  13. ASPECT spectral imaging satellite proposal to AIDA/AIM CubeSat payload

    NASA Astrophysics Data System (ADS)

    Kohout, Tomas; Näsilä, Antti; Tikka, Tuomas; Penttilä, Antti; Muinonen, Karri; Kestilä, Antti; Granvik, Mikael; Kallio, Esa

    2016-04-01

    ASPECT (Asteroid Spectral Imaging Mission) is a part of AIDA/AIM project and aims to study the composition of the Didymos binary asteroid and the effects of space weathering and shock metamorphism in order to gain understanding of the formation and evolution of the Solar System. The joint ESA/NASA AIDA (Asteroid Impact & Deflection Assessment) mission to binary asteroid Didymos consists of AIM (Asteroid Impact Mission, ESA) and DART (Double Asteroid Redirection Test, NASA). DART is targeted to impact Didymos secondary component (Didymoon) and serve as a kinetic impactor to demonstrate deflection of potentially hazardous asteroids. AIM will serve as an observational spacecraft to evaluate the effects of the impact and resulting changes in the Didymos dynamic parameters. The AIM mission will also carry two CubeSat miniaturized satellites, released in Didymoon proximity. This arrangement opens up a possibility for secondary scientific experiments. ASPECT is one of the proposed CubeSat payloads. Whereas Didymos is a space-weathered binary asteroid, the DART impactor is expected to produce a crater and excavate fresh material from the secondary component (Didymoon). Spectral comparison of the mature surface to the freshly exposed material will allow to directly deter-mine space weathering effects. It will be also possible to study spectral shock effects within the impact crater. ASPECT will also demonstrate for the first time the joint spacecraft - CubeSat operations in asteroid proximity and miniature spectral imager operation in deep-space environment. Science objectives: 1. Study of the surface composition of the Didymos system. 2. Photometric observations (and modeling) under varying phase angle and distance. 3. Study of space weathering effects on asteroids (comparison of mature / freshly exposed material). 4. Study of shock effects (spectral properties of crater interior). 5. Observations during the DART impact. Engineering objectives: 1. Demonstration of CubeSat

  14. Analysis of reentry into the White Sands Missile Range (WSMR) for the LifeSat mission

    NASA Technical Reports Server (NTRS)

    Hametz, M.; Roszman, L.; Snow, F.; Cooley, J.

    1993-01-01

    This study investigates the reentry of the LifeSat vehicles into the WSMR. The LifeSat mission consists of two reusable reentry satellites, each carrying a removable payload module, which scientists will use to study long-term effects of microgravity, Van Allen belt radiation, and galactic cosmic rays on living organisms. A series of missions is planned for both low-Earth circular orbits and highly elliptic orbits. To recover the payload module with the specimens intact, a soft parachute landing and recovery at the WSMR is planned. This analysis examines operational issues surrounding the reentry scenario to assess the feasibility of the reentry.

  15. SAT Participation and Performance and the Attainment of College and Career Readiness Benchmark Scores for the Class of 2013. Memorandum

    ERIC Educational Resources Information Center

    Sanderson, Geoffrey T.

    2013-01-01

    This memorandum describes the SAT participation and performance for the Montgomery County (Maryland) Public Schools (MCPS) Class of 2013 compared with the graduating seniors in Maryland and the nation. Detailed results of SAT and ACT by high school and student group for graduates in 2011-2013 are included. MCPS students continue to outperform the…

  16. Synthesis of Recent SAT Validity Findings: Trend Data over Time and Cohorts. Research in Review 2014-1

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Patterson, Brian F.

    2014-01-01

    In March 2005, substantial revisions were made to the SAT, to better align test specifications with K-12 curriculum (Lawrence, Rigol, Van Essen & Jackson, 2003). Over the last five years, the College Board has made a concerted effort to collect higher education outcome data to document evidence of the validity of the SAT for use in college…

  17. The Effect of the BalloonSat Project on Middle and High School Students' Attitude toward Science

    ERIC Educational Resources Information Center

    Verhage, L. Paul

    2012-01-01

    This study measured the effect of completing a BalloonSat project on student attitude toward science. Seven categories of student attitudes toward science were measured using the Test of Science Relate Attitudes survey (TOSRA). The research anticipated that the BalloonSat project would have similar effects on student attitudes as found in robotics…

  18. The coordination complex structures and hydrogen bonding in the three-dimensional alkaline earth metal salts (Mg, Ca, Sr and Ba) of (4-aminophenyl)arsonic acid.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2017-01-01

    (4-Aminophenyl)arsonic acid (p-arsanilic acid) is used as an antihelminth in veterinary applications and was earlier used in the monosodium salt dihydrate form as the antisyphilitic drug atoxyl. Examples of complexes with this acid are rare. The structures of the alkaline earth metal (Mg, Ca, Sr and Ba) complexes with (4-aminophenyl)arsonic acid (p-arsanilic acid) have been determined, viz. hexaaquamagnesium bis[hydrogen (4-aminophenyl)arsonate] tetrahydrate, [Mg(H2O)6](C6H7AsNO3)·4H2O, (I), catena-poly[[[diaquacalcium]-bis[μ2-hydrogen (4-aminophenyl)arsonato-κ(2)O:O']-[diaquacalcium]-bis[μ2-hydrogen (4-aminophenyl)arsonato-κ(2)O:O

  19. Accuracy analysis of CryoSat-2 SARIn mode data over Antarctica

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Bamber, Jonathan; Cheng, Xiao

    2015-04-01

    In 2010, CryoSat-2 was launched, carrying a unique satellite radar altimetry (SRA) instrument called SAR/Interferometric Radar Altimeter (SIRAL), with the aim of measuring and monitoring sea ice, ice sheets and mountain glaciers. The novel SAR Interferometric mode (SARInM) of CryoSat-2 is designed to improve the accuracy, resolution and geolocation of height measurements over the steeper margins of ice sheets and ice caps. Over these areas, it employs the synthetic aperture radar (SAR) capability to reduce the size of the footprint to effectively 450m along track and ~1km across track implemented from an airborne prototype originally termed a delay-Doppler altimeter. Additionally, CryoSat-2 used the phase difference between its two antennas to estimate surface slope in the across-track direction and identify the point of closed approach directly. The phase difference is 2pi for a surface slope of approximately 1deg. If the slope is above this threshold, the tracked surface in the returned waveform may be not the point of closed approach causing an error in slope correction. For this reason, the analysis was limited to slopes of 1deg or less in this study. We used extensive coverage of Antarctica provided by the ICESat laser altimeter mission between 2003 and 2009 to assess the accuracy of SARInM data. We corrected for changes in elevations due to the interval between the acquisition of the ICESat and CryoSat-2 data (from July 2010 and December 2013). Two methods were used: (1) the ICESat point was compared with a DEM derived from CryoSat-2 data (Point-to-DEM; PtoDEM), and (2) the ICESat point was compared with a CryoSat-2 point directly (Point-to-Point; PtoP). For PtoDEM, CryoSat-2 elevations were interpolated onto a regular 1km polar stereographic grid with a standard parallel of 71°S, using ordinary kriging. For PtoP, the maximum distance between a CryoSat-2 point location and ICESat point location was set to 35m. For the areas with slopes less than 0.2deg, the

  20. Operations cost Reduction for a Jovian Science Mission Using CubeSats

    NASA Astrophysics Data System (ADS)

    Rajguru, A.; Faler, A. C.

    2014-06-01

    This paper proposes the operation of a mission architecture for jovian satellite tour, that uses small orbiter 6U CubeSats, airless body landers of the same order of 6U size and a mothership carrier that will act as a communication hub to DSN.

  1. River flood events in Thailand and Bangladesh observed by CryoSat

    NASA Astrophysics Data System (ADS)

    Andersen, O. B.; Nielsen, K.; Villadsen, H.; Stenseng, L.; Knudsen, P.

    2014-12-01

    The high along track resolution of the SIRAL altimeter carried on-board CryoSat-2 offers a wide range of unique opportunities for satellite monitoring of inland water level. This study focuses on the ability of CryoSat-2 to detect the effects of flood events such as increased river levels and inundation of land. Here we study two flood events; the Bangladesh flood event of June 2012 and the flooding in Thailand that lasted between July 2011 and January 2012. The flooding in these areas was caused by abnormal monsoonal rainfall and affected millions of people. We process CryoSat-2 level 1b SAR mode data to derive water levels for the areas and compare these levels before, during and after the flooding events. Other parameters such as the backscatter coefficient and pulse peakiness are also considered. To verify the extent of the flooding observed by CryoSat-2 we compare with independent sources such as Landsat images.

  2. Discrepant SAT Critical Reading and Writing Scores: Implications for College Performance

    ERIC Educational Resources Information Center

    Shaw, Emily J.; Mattern, Krista D.; Patterson, Brian F.

    2011-01-01

    Despite the similarities that researchers note between the cognitive processes and knowledge involved in reading and writing, there are students who are much stronger readers than writers and those who are much stronger writers than readers. The addition of the writing section to the SAT provides an opportunity to examine whether certain groups of…

  3. Lipometer subcutaneous adipose tissue topography (SAT-Top) reflects serum leptin levels varying in circadian rhythms

    NASA Astrophysics Data System (ADS)

    Moeller, Reinhard; Tafeit, Erwin; Sudi, Karl; Vrecko, Karoline; Horejsi, Renate; Hinghofer-Szalkay, Helmut G.; Reibnegger, Gilbert

    1998-05-01

    Recent advances in obesity research have shown that the product of the ob-gene named leptin is related to total body fast mass in humans. There is, however, a debate if leptin levels are pulsatile and linked to body fat distribution. In this study we therefore investigated the subcutaneous adipose tissue topography (SAT-Top) measured by means of the newly developed device Lipometer and leptin levels during a 24 hours beginning at 0715am ending the same time in the next day. Blood samples for measurement of leptin were taken every 3 hours in a male subject. Measurements of SAT-Top were performed at 15 body sites from neck to calf at the left and right body site at the same time interval. We observed an almost symmetrically reaction of the left and right body site with a maximum of the mean value of all body sites in the evening at 0715pm. There was a negative correlation between serum leptin levels and SAT-Top using the set of certain body sites (R2 equals 0.80, p equals 0.01). If these combination of body sites is inversed and set against serum leptin levels, both curves show almost identical shape and time dependence. We conclude that SAT-Top by means of Lipometer is changed in a short time and related to leptin levels in the investigated male subject.

  4. A Comparison of the Kernel Equating Method with Traditional Equating Methods Using SAT[R] Data

    ERIC Educational Resources Information Center

    Liu, Jinghua; Low, Albert C.

    2008-01-01

    This study applied kernel equating (KE) in two scenarios: equating to a very similar population and equating to a very different population, referred to as a distant population, using SAT[R] data. The KE results were compared to the results obtained from analogous traditional equating methods in both scenarios. The results indicate that KE results…

  5. Georgia Is All Business as It Moves to Improve State's Showing on SAT

    ERIC Educational Resources Information Center

    Jacobson, Linda

    2005-01-01

    Students are not the only ones in Georgia fretting over scores from the recent SAT exams. More than perhaps any other state, Georgia has linked its reputation as a place to live, send children to school, and do business to the state's performance on the college-entrance test. Since Governor Sonny Perdue launched a statewide effort to raise those…

  6. NASA Near Earth Network (NEN) and Space Network (SN) Support of CubeSat Communications

    NASA Technical Reports Server (NTRS)

    Schaire, Scott H.; Shaw, Harry C.; Altunc, Serhat; Bussey, George; Celeste, Peter; Kegege, Obadiah; Wong, Yen; Zhang, Yuwen; Patel, Chitra; Raphael, David; Burke, Jacob; Cooper, La Vida; Schier, James; Horne, William; Pierce, David

    2016-01-01

    There has been a historical trend to increase capability and drive down the Size, Weight and Power (SWAP) of satellites and that trend continues today. NASA scientists and engineers across many of NASAs Mission Directorates and Centers are developing exciting CubeSat concepts and welcome potential partnerships for CubeSat endeavors. From a Telemetry, Tracking and Command (TTC) Systems and Flight Operations for Small Satellites point of view, small satellites including CubeSats are a challenge to coordinate because of existing small spacecraft constraints, such as limited SWAP and attitude control, and the potential for high numbers of operational spacecraft. The NASA Space Communications and Navigation (SCaN) Programs Near Earth Network (NEN) and Space Network (SN) are customer driven organizations that provide comprehensive communications services for space assets including data transport between a missions orbiting satellite and its Mission Operations Center (MOC). This paper presents how well the SCaN networks, SN and NEN, are currently positioned to support the emerging small small satellite and CubeSat market as well as planned enhancements for future support.

  7. NASA Near Earth Network (NEN) and Space Network (SN) CubeSat Communications

    NASA Technical Reports Server (NTRS)

    Schaire, Scott H.; Shaw, Harry; Altunc, Serhat; Bussey, George; Celeste, Peter; Kegege, Obadiah; Wong, Yen; Zhang, Yuwen; Patel, Chitra; Raphael, David; Burke, Jacob; Cooper, La Vida; Schier, James; Horne, William; Pierce, David

    2016-01-01

    There has been a recent trend to increase capability and drive down the Size, Weight and Power (SWAP) of satellites. NASA scientists and engineers across many of NASA's Mission Directorates and Centers are developing exciting CubeSat concepts and welcome potential partnerships for CubeSat endeavors. From a "Telemetry, Tracking and Command (TT&C) Systems and Flight Operations for Small Satellites" point of view, small satellites including CubeSats are a challenge to coordinate because of existing small spacecraft constraints, such as limited SWAP and attitude control, and the potential for high numbers of operational spacecraft. The NASA Space Communications and Navigation (SCaN) Program's Near Earth Network (NEN) and Space Network (SN) are customer driven organizations that provide comprehensive communications services for space assets including data transport between a mission's orbiting satellite and its Mission Operations Center (MOC). This paper presents how well the SCaN networks, SN and NEN, are currently positioned to support the emerging small small satellite and CubeSat market as well as planned enhancements for future support.

  8. Characteristics of Minority Students Who Excel on the SAT and in the Classroom. Policy Information Report

    ERIC Educational Resources Information Center

    Bridgeman, Brent; Wendler, Cathy

    2004-01-01

    After a few decades of keeping a watchful eye, substantial gaps in the average standardized test scores of White and some minority group students persist. The average group differences on the SAT are among the most visible examples of this pattern, but when we focus only on mean score differences among students, we tend to overlook the relatively…

  9. Select Psychometric Properties and Predictive Validity of Scores on the SAT Writing Section

    ERIC Educational Resources Information Center

    Proctor, Thomas P.; Kim, YoungKoung Rachel

    2009-01-01

    Presented at the national conference for the American Educational Research Association (AERA) in April 2009. This study examined the utility of scores on the SAT writing test, specifically examining the reliability of scores using generalizability and item response theories. The study also provides an overview of current predictive validity…

  10. Minority Contributions to the SAT Score Turnaround: An Example of Simpson's Paradox.

    ERIC Educational Resources Information Center

    Wainer, Howard

    1986-01-01

    Between 1980 and 1984 SAT scores rose 8 points for whites and 15 points for non-whites, but the overall mean increased only 7 points. This article explains that this is not an arithmetic error, but an example of a statistical phenomenon called Simpson's Paradox. It describes how to avoid it. (JAZ)

  11. The SAT: Four Major Modifications of the 1970-85 Era.

    ERIC Educational Resources Information Center

    Valley, John R.

    From 1970 to 1985, the Scholastic Aptitude Test (SAT) underwent major modifications caused by: (1) the addition of the Test of Standard Written English (TSWE) to the College Board's Admissions Testing Program (ATP); (2) the passage of test disclosure legislation; (3) the institution of test sensitivity reviews; and (4) the use of item response…

  12. Measuring Statistics Attitudes: Structure of the Survey of Attitudes toward Statistics (SATS-36)

    ERIC Educational Resources Information Center

    VanHoof, Stijn; Kuppens, Sofie; Sotos, Ana Elisa Castro; Verschaffel, Lieven; Onghena, Patrick

    2011-01-01

    Although a number of instruments for assessing attitudes toward statistics have been developed, several questions with regard to the structure and item functioning remain unresolved. In this study, the structure of the Survey of Attitudes Toward Statistics (SATS-36), a widely used questionnaire to measure six aspects of students' attitudes toward…

  13. Student Characteristics and the Use of the SAT Test Disclosure Materials.

    ERIC Educational Resources Information Center

    Lockheed, Marlaine E.; And Others

    Following the enactment of the New York State standardized admissions testing law, students taking the Scholastic Aptitude Test (SAT) in New York acquired the right to request a copy of test questions used in calculating their scores, a copy of their answer sheet, and various interpretive materials. This study examined (1) the differences between…

  14. Gaps in College Readiness: ACT and SAT Differences by Ethnicity across 10 School Years

    ERIC Educational Resources Information Center

    Harvey, Donzel Wayne

    2013-01-01

    Purpose: The purpose of this study was to examine the college-readiness rates of Black, Hispanic, White, and Asian graduates of public secondary schools in Texas using archival data from the Texas Education Agency Academic Excellence Indicator System. Data examined were the average ACT and SAT scores for the past 10 school years (i.e., 2001-2002…

  15. The Role of Socioeconomic Status in SAT-Freshman Grade Relationships across Gender and Racial Subgroups

    ERIC Educational Resources Information Center

    Higdem, Jana L.; Kostal, Jack W.; Kuncel, Nathan R.; Sackett, Paul R.; Shen, Winny; Beatty, Adam S.; Kiger, Thomas B.

    2016-01-01

    Recent research has shown that admissions tests retain the vast majority of their predictive power after controlling for socioeconomic status (SES), and that SES provides only a slight increment over SAT and high school grades (high school grade point average [HSGPA]) in predicting academic performance. To address the possibility that these…

  16. Application of the CloudSat and NEXRAD Radars Toward Improvements in High Resolution Operational Forecasts

    NASA Technical Reports Server (NTRS)

    Molthan, A. L.; Haynes, J. A.; Case, J. L.; Jedlovec, G. L.; Lapenta, W. M.

    2008-01-01

    As computational power increases, operational forecast models are performing simulations with higher spatial resolution allowing for the transition from sub-grid scale cloud parameterizations to an explicit forecast of cloud characteristics and precipitation through the use of single- or multi-moment bulk water microphysics schemes. investments in space-borne and terrestrial remote sensing have developed the NASA CloudSat Cloud Profiling Radar and the NOAA National Weather Service NEXRAD system, each providing observations related to the bulk properties of clouds and precipitation through measurements of reflectivity. CloudSat and NEXRAD system radars observed light to moderate snowfall in association with a cold-season, midlatitude cyclone traversing the Central United States in February 2007. These systems are responsible for widespread cloud cover and various types of precipitation, are of economic consequence, and pose a challenge to operational forecasters. This event is simulated with the Weather Research and Forecast (WRF) Model, utilizing the NASA Goddard Cumulus Ensemble microphysics scheme. Comparisons are made between WRF-simulated and observed reflectivity available from the CloudSat and NEXRAD systems. The application of CloudSat reflectivity is made possible through the QuickBeam radiative transfer model, with cautious application applied in light of single scattering characteristics and spherical target assumptions. Significant differences are noted within modeled and observed cloud profiles, based upon simulated reflectivity, and modifications to the single-moment scheme are tested through a supplemental WRF forecast that incorporates a temperature dependent snow crystal size distribution.

  17. Enhancing the Arctic Mean Sea Surface and Mean Dynamic Topography with CryoSat-2 Data

    NASA Astrophysics Data System (ADS)

    Stenseng, Lars; Andersen, Ole B.; Knudsen, Per

    2014-05-01

    A reliable mean sea surface (MSS) is essential to derive a good mean dynamic topography (MDT) and for the estimation of short and long-term changes in the sea surface. The lack of satellite radar altimetry observations above 82 degrees latitude means that existing mean sea surface models have been unreliable in the Arctic Ocean. We here present the latest DTU mean sea surface and mean dynamic topography models that includes CryoSat-2 data to improve the reliability in the Arctic Ocean. In an attempt to extrapolate across the gap above 82 degrees latitude the previously models included ICESat data, gravimetrical geoids, ocean circulation models and various combinations hereof. Unfortunately cloud cover and the short periods of operation has a negative effect on the number of ICESat sea surface observations. DTU13MSS and DTU13MDT are the new generation of state of the art global high-resolution models that includes CryoSat-2 data to extend the satellite radar altimetry coverage up to 88 degrees latitude. Furthermore the SAR and SARin capability of CryoSat-2 dramatically increases the amount of useable sea surface returns in sea-ice covered areas compared to conventional radar altimeters like ENVISAT and ERS-1/2. With the inclusion of CryoSat-2 data the new mean sea surface is improved by more than 20 cm above 82 degrees latitude compared with the previous generation of mean sea surfaces.

  18. Conquering the SAT: How Parents Can Help Teens Overcome the Pressure and Succeed

    ERIC Educational Resources Information Center

    Johnson, Ned; Eskelsen, Emily Warner

    2006-01-01

    This insightful and practical guide for parents shows how they often undermine rather than encourage their teens' success on one of the most stressful standardized tests--the SAT--and what strategies will remedy the problem. In recent years this test has taken on fearsome proportions, matched only by the growing competition for slots at major…

  19. Nine Facts about the SAT That Might Surprise You. Statistical Report

    ERIC Educational Resources Information Center

    Letukas, Lynn

    2015-01-01

    The purpose of this document is to identify and dispel rumors that are frequently cited about the SAT. The following is a compilation of nine popular rumors organized into three areas: "Student Demographics," "Test Preparation/Test Prediction," and "Test Utilization."

  20. Point of View--The Sat and the Assault on Literature

    ERIC Educational Resources Information Center

    Ruenzel, David

    2004-01-01

    It was during the early 1990s that the author began to suspect that teenagers were reading less--and less deeply--than they had been 10 and certainly 20 years ago. He found this paradoxical, because it was during the 1990s that SAT scores seemed to soar along with the economy. Students talked about them constantly, like securities traders in a…

  1. Using Additive Manufacturing to Print a CubeSat Propulsion System

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Zemba, Michael; Shemelya, Corey; Wicker, Ryan; Espalin, David; MacDonald, Eric; Keif, Craig; Kwas, Andrew

    2015-01-01

    Small satellites, such as CubeSats, are increasingly being called upon to perform missions traditionally ascribed to larger satellite systems. However, the market of components and hardware for small satellites, particularly CubeSats, still falls short of providing the necessary capabilities required by ever increasing mission demands. One way to overcome this shortfall is to develop the ability to customize every build. By utilizing fabrication methods such as additive manufacturing, mission specific capabilities can be built into a system, or into the structure, that commercial off-the-shelf components may not be able to provide. A partnership between the University of Texas at El Paso, COSMIAC at the University of New Mexico, Northrop Grumman, and the NASA Glenn Research Center is looking into using additive manufacturing techniques to build a complete CubeSat, under the Small Spacecraft Technology Program. The W. M. Keck Center at the University of Texas at El Paso has previously demonstrated the ability to embed electronics and wires into the addtively manufactured structures. Using this technique, features such as antennas and propulsion systems can be included into the CubeSat structural body. Of interest to this paper, the team is investigating the ability to take a commercial micro pulsed plasma thruster and embed it into the printing process. Tests demonstrating the dielectric strength of the printed material and proof-of-concept demonstration of the printed thruster will be shown.

  2. Keyword Mnemonic Strategy: A Study of SAT Vocabulary in High School English

    ERIC Educational Resources Information Center

    DeWitt, Kristina Callihan

    2010-01-01

    The purpose for this research study was to introduce and develop supplementary English material for SAT vocabulary instruction by providing memory-enhancing strategies for students with and without disabilities. Five inclusive English classrooms were assigned treatments in a within-subjects crossover design where all students received both…

  3. The National SAT Validity Study: Sharing Results from Recent College Success Research

    ERIC Educational Resources Information Center

    Shaw, Emily J.; McKenzie, Elizabeth

    2010-01-01

    [Slides] presented at the annual conference of the Southern Association for College Admission Counseling, April 2010. This presentation summarizes recent research from the national SAT Validity Study and includes information on the Admitted Class Evaluation Service (ACES) system and how ACES can help institutions conduct their own validity…

  4. Multidirectional Cosmic Ray Ion Detector for Deep Space CubeSats

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.

    2016-01-01

    NASA Glenn Research Center has proposed a CubeSat-based instrument to study solar and cosmic ray ions in lunar orbit or deep space. The objective of Solar Proton Anisotropy and Galactic cosmic ray High Energy Transport Instrument (SPAGHETI) is to provide multi-directional ion data to further understand anisotropies in SEP and GCR flux.

  5. The Internal Construct Validity of the SAT across Handicapped and Nonhandicapped Populations.

    ERIC Educational Resources Information Center

    Rock, Donald A.; And Others

    The comparability of Scholastic Aptitude Test (SAT) Verbal and Mathematical scores was investigated for one nonhandicapped and nine handicapped populations. The handicapped populations included hearing impaired, visually impaired, learning disabled, and physically disabled students. Special methods of test administration included Braille and large…

  6. ACT/SAT Test Preparation and Coaching Programs. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2016

    2016-01-01

    Most colleges and universities in the United States require students to take the SAT or ACT as part of the college application process. These tests are high stakes in at least three ways. First, most universities factor scores on these tests into admissions decisions. Second, higher scores can increase a student's chances of being admitted to…

  7. Use of the SAT in Advisement and Placement: What the Research Tells Us

    ERIC Educational Resources Information Center

    Shaw, Emily J.

    2009-01-01

    Presented at the College Board Western Regional Office (WRO) Forum in San Diego in February 2009. This presentation explores SAT test validity and how it can be used to inform both advisement and placement at the national or institution level. Institutional validity can be measured using the Admitted Class Evaluation Service (ACES) which schools…

  8. Unfair Treatment? The Case of Freedle, the SAT, and the Standardization Approach to Differential Item Functioning

    ERIC Educational Resources Information Center

    Santelices, Maria Veronica; Wilson, Mark

    2010-01-01

    In 2003, the "Harvard Educational Review" published a controversial article by Roy Freedle that claimed bias against African American students in the SAT college admissions test. Freedle's work stimulated national media attention and faced an onslaught of criticism from experts at the Educational Testing Service (ETS), the agency…

  9. Propulsion Technology Demonstrator. [Demonstrating Novel CubeSat Technologies in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Marmie, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    NASA's Pathfinder Technology Demonstrator (PTD) project will test the operation of a variety of novel CubeSat technologies in low- Earth orbit, providing significant enhancements to the performance of these small and effective spacecraft. Each Pathfinder Technology Demonstrator mission consists of a 6-unit (6U) CubeSat weighing approximately 26 pounds (12 kilograms) and measuring 12 inches x 10 inches x 4 inches (30 centimeters x 25 centimeters x 10 centimeters), comparable in size to a common shoebox. CubeSats are a class of nanosatellites that use a standard size and form factor. The standard Cube- Sat size uses a "one unit" or "1U" measuring 4 inches x 4 inches x 4 inches (10x10x10 centimeters) and is extendable to larger sizes by "stacking" a number of the 1U blocks to form a larger spacecraft. Each PTD spacecraft will also be equipped with deployable solar arrays that provide an average of 44 watts of power while in orbit.

  10. Cryogenic On-Orbit Liquid Depot Storage, Acquisition, and Transfer satellite (COLD-SAT) feasibility study

    NASA Technical Reports Server (NTRS)

    Bailey, William J.; Weiner, Stephen P.; Beekman, Douglas H.; Dennis, Mark F.; Martin, Timothy A.

    1990-01-01

    The Cryogenic On-Orbit Liquid Depot Storage, Acquisition, and Transfer Satellite (COLD-SAT) is an experimental spacecraft launched from an expendable launch vehicle which is designed to investigate the systems and technologies required for efficient, effective, and reliable management of cryogenic fluid in the reduced gravity space environment. The COLD-SAT program will provide the necessary data base and provide low-g proving of fluid and thermal models of cryogenic storage, transfer, and resupply concepts and processes. A conceptual approach was developed and an overview of the results of the 24 month COLD-SAT Phase A feasibility is described which includes: (1) a definition of the technology needs and the accompanying experimental 3 month baseline mission; (2) a description of the experiment subsystem, major features and rationale for satisfaction of primary and secondary experiment requirements using liquid hydrogen as the test fluid; and (3) a presentation of the conceptual design of the COLD-SAT spacecraft subsystems which support the on-orbit experiment with emphasis on areas of greatest challenge.

  11. A systematic risk management approach employed on the CloudSat project

    NASA Technical Reports Server (NTRS)

    Basilio, R. R.; Plourde, K. S.; Lam, T.

    2000-01-01

    The CloudSat Project has developed a simplified approach for fault tree analysis and probabilistic risk assessment. A system-level fault tree has been constructed to identify credible fault scenarios and failure modes leading up to a potential failure to meet the nominal mission success criteria.

  12. Development of a Solar Array Drive Assembly for CubeSat

    NASA Technical Reports Server (NTRS)

    Passaretti, Mike; Hayes, Ron

    2010-01-01

    Small satellites and in particular CubeSats, have increasingly become more viable as platforms for payloads typically requiring much larger bus structures. As advances in technology make payloads and instruments for space missions smaller, lighter and more power efficient, a niche market is emerging from the university community to perform rapidly developed, low-cost missions on very small spacecraft - micro, nano, and picosatellites. In just the last few years, imaging, biological and new technology demonstration missions have been either proposed or have flown using variations of the CubeSat structure as a basis. As these missions have become more complex, and the CubeSat standard has increased in both size (number of cubes) and mass, available power has become an issue. Body-mounted solar cells provide a minimal amount of power; deployable arrays improve on that baseline but are still limited. To truly achieve maximum power, deployed tracked arrays are necessary. To this end, Honeybee Robotics Spacecraft Mechanisms Corporation, along with MMA of Nederland Colorado, has developed a solar array drive assembly (SADA) and deployable solar arrays specifically for CubeSat missions. In this paper, we discuss the development of the SADA.

  13. Mobile CubeSat Command and Control: Assembly and Lessons Learned

    DTIC Science & Technology

    2011-09-01

    suppliers like Pumpkin , Clyde Space, and GomSpace which share exhibition booths with students from top universities around the world. The week of...integrated and tested. 1. Hardware and Software The NRL Colony I satellites, designated QbX 1 and 2, were based on the Pumpkin XS-25a CubeSat bus

  14. Determinants of Undergraduate GPAs: SAT Scores, High-School GPA and High-School Rank

    ERIC Educational Resources Information Center

    Cohn, Elchanan; Cohn, Sharon; Balch, Donald C.; Bradley, James, Jr.

    2004-01-01

    The primary purpose of the study is to assess the degree to which SAT scores, high-school GPA (HSGPA) and class rank predict success in college. Data collected from students enrolled in several sections of Principles of Economics at the University of South Carolina in 2000 and 2001 are used to study the relation between college GPA (the dependent…

  15. The CarbonSat Earth Explorer 8 candidate mission: Error analysis for carbon dioxide and methane

    NASA Astrophysics Data System (ADS)

    Buchwitz, Michael; Bovensmann, Heinrich; Reuter, Maximilian; Gerilowski, Konstantin; Meijer, Yasjka; Sierk, Bernd; Caron, Jerome; Loescher, Armin; Ingmann, Paul; Burrows, John P.

    2015-04-01

    CarbonSat is one of two candidate missions for ESA's Earth Explorer 8 (EE8) satellite to be launched around 2022. The main goal of CarbonSat is to advance our knowledge on the natural and man-made sources and sinks of the two most important anthropogenic greenhouse gases (GHGs) carbon dioxide (CO2) and methane (CH4) on various temporal and spatial scales (e.g., regional, city and point source scale), as well as related climate feedbacks. CarbonSat will be the first satellite mission optimised to detect emission hot spots of CO2 (e.g., cities, industrialised areas, power plants) and CH4 (e.g., oil and gas fields) and to quantify their emissions. Furthermore, CarbonSat will deliver a number of important by-products such as Vegetation Chlorophyll Fluorescence (VCF, also called Solar Induced Fluorescence (SIF)) at 755 nm. These applications require appropriate retrieval algorithms which are currently being optimized and used for error analysis. The status of this error analysis will be presented based on the latest version of the CO2 and CH4 retrieval algorithm and taking the current instrument specification into account. An overview will be presented focusing on nadir observations over land. Focus will be on specific issues such as errors of the CO2 and CH4 products due to residual polarization related errors and errors related to inhomogeneous ground scenes.

  16. SeaSat-A Satellite Scatterometer (SASS) Validation and Experiment Plan

    NASA Technical Reports Server (NTRS)

    Schroeder, L. C. (Editor)

    1978-01-01

    This plan was generated by the SeaSat-A satellite scatterometer experiment team to define the pre-and post-launch activities necessary to conduct sensor validation and geophysical evaluation. Details included are an instrument and experiment description/performance requirements, success criteria, constraints, mission requirements, data processing requirement and data analysis responsibilities.

  17. Time-Resolved CubeSat Photometry with a Low Cost Electro-Optics System

    NASA Astrophysics Data System (ADS)

    Gasdia, F.; Barjatya, A.; Bilardi, S.

    2016-09-01

    Once the orbits of small debris or CubeSats are determined, optical rate-track follow-up observations can provide information for characterization or identification of these objects. Using the Celestron 11" RASA telescope and an inexpensive CMOS machine vision camera, we have obtained time-series photometry from dozens of passes of small satellites and CubeSats over sites in Florida and Massachusetts. The fast readout time of the CMOS detector allows temporally resolved sampling of glints from small wire antennae and structural facets of rapidly tumbling objects. Because the shape of most CubeSats is known, these light curves can be used in a mission support function for small satellite operators to diagnose or verify the proper functioning of an attitude control system or deployed antenna or instrument. We call this telescope system and the accompanying analysis tools OSCOM for Optical tracking and Spectral characterization of CubeSats for Operational Missions. We introduce the capability of OSCOM for space object characterization, and present photometric observations demonstrating the potential of high frame rate small satellite photometry.

  18. Autonomous planning and scheduling on the TechSat 21 mission

    NASA Technical Reports Server (NTRS)

    Sherwood, R.; Chien, S.; Castano, R.; Rabideau, G.

    2002-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting.

  19. Could There Be a Medical Basis for the Declining SAT Scores?

    ERIC Educational Resources Information Center

    Arnold, Charles B.

    The scores of the Scholastic Aptitude Test (SAT) have been declining since 1963. While this decline has occurred, scores on achievement tests administered to students in grades 3 to 11 have been stable. An alalysis of the medical and epidemiological literature was conducted to determine whether there could be a health factor that might have caused…

  20. A Fractionated Space Weather Base at L5 using CubeSats and Solar Sails

    NASA Astrophysics Data System (ADS)

    Liewer, Paulett C.; Klesh, A.; Lo, M.; Murphy, N.; Staehle, R. L.; Vourlidas, A.; Cutler, J. W.; Lightsey, G.

    2013-07-01

    The Sun-Earth L5 Lagrange point is an ideal location for an operational space weather mission to provide early warning of Earth-directed solar storms (CMEs, shocks and associated solar energetic particles) so the effects on power grids, spacecraft and communications systems can be mitigated. Such missions have been proposed using conventional spacecraft and chemical propulsion at costs of hundreds of millions of dollars. Here we describe a mission that can accomplish the goals at a much lower cost by dividing the payload among a cluster of interplanetary CubeSats that reach orbits around L5 using solar sails. The ascendancy of CubeSats has brought renewed interest in solar sail propulsion because sail area scales directly with spacecraft mass. The concept presented here draws heavily on a NIAC study (Staehle et al., AIAA, 2012) that developed a 6U CubeSat architecture for interplanetary missions. This study allocated 2U for a solar sail; the sail system was based on the Planetary Society’s LightSail-1TM architecture. At a recent workshop on small satellites, hosted by the Keck Institute for Space Studies, a concept was developed for a fractionated Space Weather Base (SWB) at L5. In this concept, a loose formation of CubeSats, each ~6U in size and each carrying a portion of the science payload, can accomplish, at a much reduced cost, many of the goals of a conventional single-spacecraft L5 mission, as described in the 2013 NRC Solar and Space Physics Decadal report. Each of the small ~6U interplanetary CubeSats reaches an orbit around L5 using its own solar sail of approximately 64 m2 which fits in ~2U. Key to the mission is that only one of the CubeSats carries a high-gain antenna and other hardware necessary for sending high-rate science data to Earth. The other CubeSats, in addition to carrying one or two science instruments, carry a much smaller communication system to send the science data to the communication hub and low-rate engineering data to Earth. The

  1. Interplanetary CubeSats system for space weather evaluations and technology demonstration

    NASA Astrophysics Data System (ADS)

    Viscio, Maria Antonietta; Viola, Nicole; Corpino, Sabrina; Stesina, Fabrizio; Fineschi, Silvano; Fumenti, Federico; Circi, Christian

    2014-11-01

    The paper deals with the mission analysis and conceptual design of an interplanetary 6U CubeSats system to be implemented in the L1 Earth-Sun Lagrangian Point mission for solar observation and in-situ space weather measurements. Interplanetary CubeSats could be an interesting alternative to big missions, to fulfill both scientific and technological tasks in deep space, as proved by the growing interest in this kind of application in the scientific community and most of all at NASA. Such systems allow less costly missions, due to their reduced sizes and volumes, and consequently less demanding launches requirements. The CubeSats mission presented in this paper is aimed at supporting measurements of space weather. The mission envisages the deployment of a 6U CubeSats system in the L1 Earth-Sun Lagrangian Point, where solar observations for in situ measurements of space weather to provide additional warning time to Earth can be carried out. The proposed mission is also intended as a technology validation mission, giving the chance to test advanced technologies, such as telecommunications and solar sails, envisaged as propulsion system. Furthermore, traveling outside the Van Allen belts, the 6U CubeSats system gives the opportunity to further investigate the space radiation environment: radiation dosimeters and advanced materials are envisaged to be implemented, in order to test their response to the harsh space environment, even in view of future implementation on other spacecrafts (e.g. manned spacecrafts). The main issue related to CubeSats is how to fit big science within a small package - namely power, mass, volume, and data limitations. One of the objectives of the work is therefore to identify and size the required subsystems and equipment, needed to accomplish specific mission objectives, and to investigate the most suitable configuration, in order to be compatible with the typical CubeSats (multi units) standards. The work has been developed as collaboration

  2. A Potential Operational CryoSat Follow-on Mission Concept and Design

    NASA Astrophysics Data System (ADS)

    Cullen, R.

    2015-12-01

    CryoSat was a planned as a 3 year mission with clear mission objectives to allow the assessment rates of change of thickness in the land and marine ice fields with reduced uncertainties with relation to other non-dedicated missions. Although CryoSat suffered a launch failure in Oct 2005, the mission was recovered with a launch in April 2010 of CryoSat-2. The nominal mission has now been completed, all mission requirements have been fulfilled and CryoSat has been shown to be most successful as a dedicated polar ice sheet measurement system demonstrated by nearly 200 peer reviewed publications within the first four years of launch. Following the completion of the nominal mission in Oct 2013 the platform was shown to be in good health and with a scientific backing provided by the ESA Earth Science Advisory Committee (ESAC) the mission has been extended until Feb 2017 by the ESA Programme Board for Earth Observation. Though not designed to provide data for science and operational services beyond its original mission requirements, a number of services have been developed for exploitation and these are expected to increase over the next few years. Services cover a number of aspects of land and marine ice fields in addition to complementary activities covering glacial monitoring, inland water in addition to coastal and open ocean surface topography science that CryoSat has demonstrated world leading advances with. This paper will present the overall concept for a potential low-cost follow-on to the CryoSat mission with the objective to provide both continuity of the existing CryoSat based data sets, i.e., longer term science and operational services that cannot be provided by the existing Copernicus complement of satellites. This is, in part, due to the high inclination (92°) drifting orbit and state of the art Synthetic Aperture Interferometer Radar Altimeter (SIRAL). In addition, further improvements in performance are expected by use of the instrument timing and

  3. The CloudSat Education Network: A Model for Worldwide Scientist/Student/Teacher/Community Partnerships

    NASA Astrophysics Data System (ADS)

    Krumm, D. K.; Lockett, J. L.

    2005-05-01

    CloudSat, a NASA Earth System Science Pathfinder Mission, will launch into orbit the world's most advanced weather radar designed to measure properties of clouds that are essential for accurate understanding of Earth's weather and climate processes. Providing the first vertical profiles of global measurements of cloud thickness, height, water and ice content and a wide range of precipitation data linked to cloud development, CloudSat measurements will fill a critical gap in understanding how clouds affect climate (http://cloudsat.atmos.colostate.edu/). Any mission of this nature requires extensive ground-based reference data. The CloudSat Education Network provides the opportunity for schools around the world to partner with the CloudSat Science and Education Teams. The Network will use proven science and education programs such as GLOBE (http://www.globe.gov) to link together scientists, students, teachers, and their communities to give students meaningful, authentic and contemporary high quality educational experiences. Student activities and learning outcomes designed within the program have been chosen to meet both general education outcomes and specific standards or objectives from local school curricula. The main focus of the knowledge development component of the project is to help students better understand long-term climate change and the climatic processes that maintain the Earth's Energy balance. Scientists will receive research-quality data in support of the mission and in return interact with students, teachers and their students to promote interest in science. Launch of the CloudSat satellite is anticipated for mid 2005. Participation in the network throughout the duration of the project will be monitored and schools will need to maintain levels of participation in order to maintain "Membership" in the network. The base level of participation is the reporting of environmental data identified in the project every 16 days coinciding with the CloudSat

  4. Improved Oceanographic Measurements with CryoSat SAR Altimetry: Application to the Coastal Zone and Arctic

    NASA Astrophysics Data System (ADS)

    Cotton, David; Nilo Garcia, Pablo; Cancet, Mathilde; Andersen, Ole; Stenseng, Lars; Martin, Francisco; Cipollini, Paolo; Benveniste, Jérôme; Restano, Marco; Ambrósio, Américo

    2016-04-01

    The ESA CryoSat mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar "SAR" (or delay-Doppler) and interferometric SAR (SARin) modes. Studies on CryoSat data have analysed and confirmed the improved ocean measuring capability offered by SAR mode altimetry, through increased resolution and precision in sea surface height and wave height measurements, and have also added significantly to our understanding of the issues around the processing and interpretation of SAR altimeter echoes. We present work in four themes, building on work initiated in the CryoSat Plus for Oceans project (CP4O), each investigating different aspects of the opportunities offered by this new technology. The first two studies address the coastal zone, a critical region for providing a link between open-ocean and shelf sea measurements with those from coastal in-situ measurements, in particular tide gauges. Although much has been achieved in recent years through the Coastal Altimetry community, (http://www.coastalt.eu/community) there is a limit to the capabilities of pulse-limited altimetry which often leaves an un-measured "white strip" right at the coastline. Firstly, a thorough analysis was made of the performance of "SAR" altimeter data (delay-Doppler processed) in the coastal zone. This quantified the performance, confirming the significant improvement over "conventional" pulse-limited altimetry. In the second study a processing scheme was developed with CryoSat SARin mode data to enable the retrieval of valid oceanographic measurements in coastal areas with complex topography. Thanks to further development of the algorithms, a new approach was achieved that can also be applied to SAR and conventional altimetry data (e.g., Sentinel-3, Jason series, EnviSat). The third part of the project developed and evaluated improvements to the SAMOSA altimeter re-tracker that is implemented in the Sentinel-3 processing chain. The modifications to the

  5. An Optimum Space-to-Ground Communication Concept for CubeSat Platform Utilizing NASA Space Network and Near Earth Network

    NASA Technical Reports Server (NTRS)

    Wong, Yen F.; Kegege, Obadiah; Schaire, Scott H.; Bussey, George; Altunc, Serhat; Zhang, Yuwen; Patel Chitra

    2016-01-01

    National Aeronautics and Space Administration (NASA) CubeSat missions are expected to grow rapidly in the next decade. Higher data rate CubeSats are transitioning away from Amateur Radio bands to higher frequency bands. A high-level communication architecture for future space-to-ground CubeSat communication was proposed within NASA Goddard Space Flight Center. This architecture addresses CubeSat direct-to-ground communication, CubeSat to Tracking Data Relay Satellite System (TDRSS) communication, CubeSat constellation with Mothership direct-to-ground communication, and CubeSat Constellation with Mothership communication through K-Band Single Access (KSA). A study has been performed to explore this communication architecture, through simulations, analyses, and identifying technologies, to develop the optimum communication concepts for CubeSat communications. This paper presents details of the simulation and analysis that include CubeSat swarm, daughter ship/mother ship constellation, Near Earth Network (NEN) S and X-band direct to ground link, TDRSS Multiple Access (MA) array vs Single Access mode, notional transceiver/antenna configurations, ground asset configurations and Code Division Multiple Access (CDMA) signal trades for daughter ship/mother ship CubeSat constellation inter-satellite cross link. Results of space science X-band 10 MHz maximum achievable data rate study are summarized. CubeSat NEN Ka-Band end-to-end communication analysis is provided. Current CubeSat communication technologies capabilities are presented. Compatibility test of the CubeSat transceiver through NEN and SN is discussed. Based on the analyses, signal trade studies and technology assessments, the desired CubeSat transceiver features and operation concepts for future CubeSat end-to-end communications are derived.

  6. Electrospray Thrusters for Attitude Control of a 1-U CubeSat

    NASA Astrophysics Data System (ADS)

    Timilsina, Navin

    With a rapid increase in the interest in use of nanosatellites in the past decade, finding a precise and low-power-consuming attitude control system for these satellites has been a real challenge. In this thesis, it is intended to design and test an electrospray thruster system that could perform the attitude control of a 1-unit CubeSat. Firstly, an experimental setup is built to calculate the conductivity of different liquids that could be used as propellants for the CubeSat. Secondly, a Time-Of-Flight experiment is performed to find out the thrust and specific impulse given by these liquids and hence selecting the optimum propellant. On the other hand, a colloidal thruster system for a 1-U CubeSat is designed in Solidworks and fabricated using Lathe and CNC Milling Machine. Afterwards, passive propellant feeding is tested in this thruster system. Finally, the electronic circuit and wireless control system necessary to remotely control the CubeSat is designed and the final testing is performed. Among the propellants studied, Ethyl ammonium nitrate (EAN) was selected as the best propellant for the CubeSat. Theoretical design and fabrication of the thruster system was performed successfully and so was the passive propellant feeding test. The satellite was assembled for the final experiment but unfortunately the microcontroller broke down during the first test and no promising results were found out. However, after proving that one thruster works with passive feeding, it could be said that the ACS testing would have worked if we had performed vacuum compatibility tests for other components beforehand.

  7. MarsCAT: Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster

    NASA Astrophysics Data System (ADS)

    Bering, Edgar Andrew; Pinsky, Lawrence S.; Li, Liming; Jackson, David; Chen, Ji; Reed, Helen; Moldwin, Mark; Kasper, Justin; Sheehan, J. P.; Forbes, James Richard; Heine, Thomas; Case, Anthony; Stevens, Michael; Sibeck, David G.

    2015-11-01

    The MarsCAT (Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster) Mission is a two 6U CubeSat mission to study the ionosphere of Mars proposed for the NASA SIMPLeX opportunity. The mission will investigate the plasma and magnetic structure of the Martian ionosphere, including transient plasma structures, magnetic field structure and dynamics, and energetic particle activity. The transit plan calls for a piggy back ride with Mars 2020 using a CAT burn for MOI, the first demonstration of CubeSat propulsion for interplanetary travel. MarsCAT will make correlated multipoint studies of the ionosphere and magnetic field of Mars. Specifically, the two spacecraft will make in situ observations of the plasma density, temperature, and convection in the ionosphere of Mars. They will also make total electron content measurements along the line of sight between the two spacecraft and simultaneous 3-axis local magnetic field measurements in two locations. Additionally, MarsCAT will demonstrate the performance of new CubeSat telemetry antennas designed at the University of Houston that are designed to be low profile, rugged, and with a higher gain than conventional monopole (whip) antennas. The two MarsCAT CubeSats will have five science instruments: a 3-axis DC magnetometer, adouble-Langmuir probe, a Faraday cup, a solid state energetic particle detector (Science Enhancement Option), and interspacecraft total electron content radio occulation experiment. The MarsCAT spacecraft will be solar powered and equipped with a CAT thruster that can provide up to 4.8 km/s of delta-V, which is sufficient to achieve Mars orbit using the Mars 2020 piggyback. They have an active attitude control system, using a sun sensor and flight-proven star tracker for determination, and momentum wheels for 3-axis attitude control.

  8. MarsCAT: Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster

    NASA Astrophysics Data System (ADS)

    Bering, E. A., III; Pinsky, L.; Li, L.; Jackson, D. R.; Chen, J.; Reed, H.; Moldwin, M.; Kasper, J. C.; Sheehan, J. P.; Forbes, J.; Heine, T.; Case, A. W.; Stevens, M. L.; Sibeck, D. G.

    2015-12-01

    The MarsCAT (Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster) Mission is a two 6U CubeSat mission to study the ionosphere of Mars proposed for the NASA SIMPLeX opportunity. The mission will investigate the plasma and magnetic structure of the Martian ionosphere, including transient plasma structures, magnetic field structure and dynamics, and energetic particle activity. The transit plan calls for a piggy back ride with Mars 2020 using a CAT burn for MOI, the first demonstration of CubeSat propulsion for interplanetary travel. MarsCAT will make correlated multipoint studies of the ionosphere and magnetic field of Mars. Specifically, the two spacecraft will make in situ observations of the plasma density, temperature, and convection in the ionosphere of Mars. They will also make total electron content measurements along the line of sight between the two spacecraft and simultaneous 3-axis local magnetic field measurements in two locations. Additionally, MarsCAT will demonstrate the performance of new CubeSat telemetry antennas designed at the University of Houston that are designed to be low profile, rugged, and with a higher gain than conventional monopole (whip) antennas. The two MarsCAT CubeSats will have five science instruments: a 3-axis DC magnetometer, adouble-Langmuir probe, a Faraday cup, a solid state energetic particle detector (Science Enhancement Option), and interspacecraft total electron content radio occulation experiment. The MarsCAT spacecraft will be solar powered and equipped with a CAT thruster that can provide up to 4.8 km/s of delta-V, which is sufficient to achieve Mars orbit using the Mars 2020 piggyback. They have an active attitude control system, using a sun sensor and flight-proven star tracker for determination, and momentum wheels for 3-axis attitude control.

  9. Fine Ice Sheet margins topography from swath processing of CryoSat SARIn mode data

    NASA Astrophysics Data System (ADS)

    Foresta, Luca; Gourmelen, Noel; Shepherd, Andrew; Escorihuela, Maria Jose; Muir, Alan; Briggs, Kate; Roca, Monica; Baker, Steven; Drinkwater, Mark; Nienow, Pete

    2014-05-01

    Reference and repeat-observations of Glacier and Ice Sheet Margin (GISM) topography are critical to identify changes in ice thickness, provide estimates of mass gain or loss and thus quantify the contribution of the cryosphere to sea level change. The lack of such sustained observations was identified in the Integrated Global Observing Strategy (IGOS) Cryosphere Theme Report as a major shortcoming. Conventional altimetry measurements over GISMs exist, but coverage has been sparse and characterized by coarse ground resolution. Additionally, and more importantly, they proved ineffective in the presence of steep slopes, a typical feature of GISM areas. Since the majority of Antarctic and Greenland ice sheet mass loss is estimated to lie within 100 km from the coast, but only about 10% is surveyed, there is the need for more robust and dense observations of GISMs, in both time and space. The ESA Altimetry mission CryoSat aims at gaining better insight into the evolution of the Cryosphere. CryoSat's revolutionary design features a Synthetic Interferometric Radar Altimeter (SIRAL), with two antennas for interferometry. The corresponding SAR Interferometer (SARIn) mode of operation increases spatial resolution while resolving the angular origin of off-nadir echoes occurring over sloping terrain. The SARIn mode is activated over GISMs and the elevation for the Point Of Closest Approach (POCA) is a standard product of the CryoSat mission. Here we present a new approach for more comprehensively exploiting the SARIn mode of CryoSat and produce an ice elevation product with enhanced spatial resolution compared to standard CryoSat-2 height products. In this so called L2-swath processing approach, the signal beyond the POCA is exploited when signal and surface characteristics are favourable. We will present the rationale, validation exercises and preliminary results from the STSE CryoTop study over selected test regions of the margins of the Greenland and Antarctic Ice Sheets.

  10. Time series over the Brahmaputra River from CryoSat-2/SIRAL altimetry

    NASA Astrophysics Data System (ADS)

    Villadsen, Heidi; Baltazar Andersen, Ole; Knudsen, Per; Nielsen, Karina; Stenseng, Lars

    2014-05-01

    CryoSat-2 was launched in 2010 with the purpose of monitoring polar ice caps, but the satellite has also proven to be useful for studies at lower latitudes. CryoSat-2 carries a new type of instrument, the SIRAL altimeter, which implements SAR and SARIn mode in addition to the standard LRM. In these modes the along-track resolution is 300m, giving rise to new opportunities for inland water altimetry, which requires a high along-track resolution in order to accurately capture the return signals from the water bodies. Here, we have investigated the possibilities for monitoring river water levels with CryoSat-2 as a part of the EU FP7 LOTUS (Preparing Land and Ocean Take Up from Sentinel-3). The LOTUS project will develop new methodologies, data processing chains, and applications of the SAR mode data for the inland water levels in rivers and lakes. Time series analysis for CryoSat-2 altimetry is not straightforward due to the satellite's very long repeat period of 369 days. It is therefore necessary to take new methods into use. Using slope correction, i.e. taking advantage of the drifting orbit, we have derived time series from retracked heights in all three modes of the CryoSat-2 altimeter over the Brahmaputra River. From the time series we can estimate the amplitude and the seasonal signal of the flow in the river. Presented here is a comparison of the results between modes and with Envisat time series.

  11. An improved wet tropospheric correction for CryoSat-2 over open and coastal ocean

    NASA Astrophysics Data System (ADS)

    Joana Fernandes, M.; Lázaro, Clara; Nunes, Alexandra L.; Pires, Nelson; Dinardo, Salvatore; Benveniste, Jérôme

    2014-05-01

    In the scope of the CryoSat Plus for Oceans (CP4O) project, encouraged by the European Space Agency, a data combination (DComb) algorithm has been developed for the computation of the wet tropospheric correction (WTC) for CryoSat-2, which does not possess an onboard microwave radiometer (MWR), thus relying on a model-based WTC provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). This WTC is based on the objective analysis of all available wet path delay data sources (e.g. from scanning imaging MWR (SI MWR) on board remote sensing satellites, those derived from Global Navigation Satellite Systems (GNSS) measurements at coastal stations and from an atmospheric model such as the ECMWF ReAnalysis (ERA) Interim. This presentation gives a brief description of the DComb algorithm and its application to CryoSat-2. The algorithm was first applied to Jason-2 and compared with the correction from the Jason-2 advanced microwave radiometer (AMR) present on the version D of the Geophysical Data Records (GDR-D), known to be a well calibrated and accurate correction, with improved performance in coastal regions. These results show that for epochs and locations for which SI-MWR measurements are available, the DComb WTC is very similar to that of AMR, evidencing that the SI-MWR water vapour products, previously calibrated with respect to AMR, are an extremely valuable data set for the estimation of the WTC for any altimeter mission, including those which possess an onboard MWR. For both Jason-2 and CryoSat-2 the new correction was validated through analysis of sea level anomaly variance at crossovers, function of distance from the coast and latitude. The influence of the GNSS-derived wet path delays in the coastal regions, of major importance for the full exploitation of CryoSat-2 data, in particular those acquired in the Synthetic Aperture Radar (SAR) mode, is also shown.

  12. Near-real-time Arctic sea ice thickness and volume from CryoSat-2

    NASA Astrophysics Data System (ADS)

    Tilling, Rachel L.; Ridout, Andy; Shepherd, Andrew

    2016-09-01

    Timely observations of sea ice thickness help us to understand the Arctic climate, and have the potential to support seasonal forecasts and operational activities in the polar regions. Although it is possible to calculate Arctic sea ice thickness using measurements acquired by CryoSat-2, the latency of the final release data set is typically 1 month due to the time required to determine precise satellite orbits. We use a new fast-delivery CryoSat-2 data set based on preliminary orbits to compute Arctic sea ice thickness in near real time (NRT), and analyse this data for one sea ice growth season from October 2014 to April 2015. We show that this NRT sea-ice-thickness product is of comparable accuracy to that produced using the final release CryoSat-2 data, with a mean thickness difference of 0.9 cm, demonstrating that the satellite orbit is not a critical factor in determining sea ice freeboard. In addition, the CryoSat-2 fast-delivery product also provides measurements of Arctic sea ice thickness within 3 days of acquisition by the satellite, and a measurement is delivered, on average, within 14, 7 and 6 km of each location in the Arctic every 2, 14 and 28 days respectively. The CryoSat-2 NRT sea-ice-thickness data set provides an additional constraint for short-term and seasonal predictions of changes in the Arctic ice cover and could support industries such as tourism and transport through assimilation in operational models.

  13. A 6U CubeSat Constellation for Atmospheric Temperature and Humidity Sounding

    NASA Technical Reports Server (NTRS)

    Padmanabhan, Sharmila; Brown, Shannon; Kangaslahti, Pekka; Cofield, Richard; Russell, Damon; Stachnik, Robert; Steinkraus, Joel; Lim, Boon

    2013-01-01

    We are currently developing a 118/183 GHz sensor that will enable observations of temperature and precipitation profiles over land and ocean. The 118/183 GHz system is well suited for a CubeSat deployment as 10cm antenna aperture provides sufficiently small footprint sizes (is approx. 25km). This project will enable low cost, compact radiometer instrumentation at 118 and 183 GHz that would fit in a 6U CubeSat with the objective of mass-producing this design to enable a suite of small satellites to image the key geophysical parameters that are needed to improve prediction of extreme weather events. We will take advantage of past and current technology developments at JPL viz. HAMSR (High Altitude Microwave Scanning Radiometer), Advanced Component Technology (ACT'08) to enable low-mass and low-power high frequency airborne radiometers. The 35 nm InP enabling technology provides significant reduction in power consumption (Low Noise Amplifier + Mixer Block consumes 24 mW). In this paper, we will describe the design and implementation of the 118 GHz temperature sounder and 183 GHz humidity sounder instrument on the 6U CubeSat. In addition, a summary of radiometer calibration and retrieval techniques of the temperature and humidity will be discussed. The successful demonstration of this instrument on the 6U CubeSat would pave the way for the development of a constellation consisting of suite of these instruments. The proposed constellation of these 6U CubeSat radiometers would allow sampling of tropospheric temperature and humidity with fine temporal (on the order of minutes) and spatial resolution (is approx. 25 km).

  14. Measurement approach and design of the CubeSat Infrared Atmospheric Sounder (CIRAS)

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Rider, David; Rud, Mayer; Ting, David; Yee, Karl

    2016-09-01

    The CubeSat Infrared Atmospheric Sounder (CIRAS) will measure upwelling infrared radiation of the Earth in the MWIR region of the spectrum from space on a CubeSat. The observed radiances have information of potential value to weather forecasting agencies and can be used to retrieve lower tropospheric temperature and water vapor globally for weather and climate science investigations. Multiple units can be flown to improve temporal coverage or in formation to provide new data products including 3D atmospheric motion vector winds. CIRAS incorporates key new instrument technologies including a 2D array of High Operating Temperature Barrier Infrared Detector (HOT-BIRD) material, selected for its high uniformity, low cost, low noise and higher operating temperatures than traditional materials. The detectors are hybridized to a commercial ROIC and commercial camera electronics. The second key technology is an MWIR Grating Spectrometer (MGS) designed to provide imaging spectroscopy for atmospheric sounding in a CubeSat volume. The MGS has no moving parts and includes an immersion grating to reduce the volume and reduce distortion. The third key technology is an infrared blackbody fabricated with black silicon to have very high emissivity in a flat plate construction. JPL will also develop the mechanical, electronic and thermal subsystems for CIRAS, while the spacecraft will be a commercially available CubeSat. The integrated system will be a complete 6U CubeSat capable of measuring temperature and water vapor profiles with good lower tropospheric sensitivity. The CIRAS is the first step towards the development of an Earth Observation Nanosatellite Infrared (EON-IR) capable of operational readiness to mitigate a potential loss of CrIS on JPSS or complement the current observing system with different orbit crossing times.

  15. In-depth analyses of oceanic CloudSat reflectivity profiles burdened by multiple-scattering

    NASA Astrophysics Data System (ADS)

    Battaglia, A.; Simmer, C.

    2009-04-01

    Multiple scattering strongly affects the CloudSat Profiling Radar reflectivity when the satellite is over-passing moderate and heavy precipitation systems. Following a criterion developed by the authors in the past (Battaglia et al., 2008) and based on the freezing level altitude (FLA) and on the path integrated attenuation (PIA), oceanic CloudSat reflectivities profiles affected by multiple scattering are identified and further analysed. Profiles are clustered according to PIA, FLA, position and value of the profile maximum reflectivity, jump of the reflectivity from pixels close to the surface to the surface pixel. This last variable represents a rough estimate of the multiple-scattering strength, i.e. of the reflectivity enhancement produced by higher-than-one scattering orders in proximity to the surface. The slopes of the reflectivity profiles (which results from the combined effect of vertical variability, attenuation and multiple scattering) are then computed at different altitudes above the surface and their variability is discussed in relationships to the profile characteristic variables. Results from one full year of CloudSat data are discussed and compared with numerical simulation outputs based on Cloud Resolving Model (Battaglia and Simmer 2008). This study has strong relevance for attenuation-based retrievals of rainfall from high frequency space-borne radars (Matrosov et al., 2008). Battaglia, A., J. Haynes, T. L'Ecuyer, and C. Simmer, Identifying multiple-scattering-affected profiles in CloudSat observations over the Oceans, J. Geoph. Res., 113, D00A17, doi:101029/2008JD009960 Battaglia, A., and C. Simmer, How does multiple scattering affect the spaceborne W-band radar measurements at ranges close to and crossing the surface-range?, IEEE Tran. Geo. Rem. Sens., , Vol. 46, No. 6,1644-1651, 2008 Matrosov, S., Battaglia, A., Rodriguez, P. Effects of multiple scattering on attenuation-based retrievals of stratiform rainfall from CloudSat, J. Atm. Oc

  16. Micro Cathode Arc Thruster for PhoneSat: Development and Potential Applications

    NASA Technical Reports Server (NTRS)

    Gazulla, Oriol Tintore; Perez, Andres Dono; Agasid, Elwood; Uribe, Eddie; Trinh, Greenfield; Keidar, Michael; Teel, George; Haque, Samudra; Lukas, Joseph; Salas, Alberto Guillen; Wolfe, Jasper; Attai, Watson; Oyadomari, Ken; Priscal, Cedric; Schimmin, Rogan

    2014-01-01

    NASA Ames Research Center and the George Washington University are developing an electric propulsion subsystem that will be integrated into the PhoneSat bus. Experimental tests have shown a reliable performance by firing three different thrusters at various frequencies in vacuum conditions. The interface consists of a microcontroller that sends a trigger pulse to the Pulsed Plasma Unit that is responsible for the thruster operation. A Smartphone is utilized as the main user interface for the selection of commands that control the entire system. The propellant, which is the cathode itself, is a solid cylinder made of Titanium. This simplicity in the design avoids miniaturization and manufacturing problems. The characteristics of this thruster allow an array of µCATs to perform attitude control and orbital correction maneuvers that will open the door for the implementation of an extensive collection of new mission concepts and space applications for CubeSats. NASA Ames is currently working on the integration of the system to fit the thrusters and the PPU inside a 1.5U CubeSat together with the PhoneSat bus. This satellite is intended to be deployed from the ISS in 2015 and test the functionality of the thrusters by spinning the satellite around its long axis and measure the rotational speed with the phone gyros. This test flight will raise the TRL of the propulsion system from 5 to 7 and will be a first test for further CubeSats with propulsion systems, a key subsystem for long duration or interplanetary small satellite missions.

  17. Intra-serotype SAT2 chimeric foot-and-mouth disease vaccine protects cattle against FMDV challenge.

    PubMed

    Maree, Francois F; Nsamba, Peninah; Mutowembwa, Paidamwoyo; Rotherham, Lia S; Esterhuysen, Jan; Scott, Katherine

    2015-06-09

    The genetic diversity of the three Southern African Territories (SAT) types of foot-and-mouth disease virus (FMDV) reflects high antigenic variation, and indications are that vaccines targeting each SAT-specific topotype may be needed. This has serious implications for control of FMD using vaccines as well as the choice of strains to include in regional antigen banks. Here, we investigated an intra-serotype chimeric virus, vSAT2(ZIM14)-SAT2, which was engineered by replacing the surface-exposed capsid-coding region (1B-1D/2A) of a SAT2 genome-length clone, pSAT2, with that of the field isolate, SAT2/ZIM/14/90. The chimeric FMDV produced by this technique was viable, grew to high titres and stably maintained the 1B-1D/2A sequence upon passage. Chemically inactivated, oil adjuvanted vaccines of both the chimeric and parental immunogens were used to vaccinate cattle. The serological response to vaccination showed the production of strong neutralizing antibody titres that correlated with protection against homologous FMDV challenge. We also predicted a good likelihood that cattle vaccinated with an intra-serotype chimeric vaccine would be protected against challenge with viruses that caused recent outbreaks in southern Africa. These results provide support that chimeric vaccines containing the external capsid of field isolates induce protective immune responses in FMD host species similar to the parental vaccine.

  18. TacSat-2: Path finder for a Close Space Support Asset

    NASA Astrophysics Data System (ADS)

    Bhopale, A.; Finley, C.

    2008-08-01

    With th e launch of TacSat-2, the Oper ationally Responsive Sp ace (O RS) commun ity had its f irst on- orbit asset and opportunity to prove or disprove the premise that small, in expensiv e, and quickly constructed spacecraf t could perform useful operation al missions when needed and for as long as need ed. All of the components of the comp lex TacSat-2 system had to work together to answer the basic questions, "In a crisis, can a lab-developed spacecraf t and ground architecture competen tly p erform th e mission of systems that cost twen ty times the price and tak e four times as long to develop? Mor eover, can th is system actu ally improve on the responsiveness of Nation al Systems to a certain set of underserv ed Oper ational customers?" When all w as said and done, TacSat-2 was a sp acecraf t that h ad to: 1) Carry th irteen tactical and scientific payloads to orbit, many of which doubled as essen tial, non-redundant subsystems; 2) Launch from an unproven launch base on a last minute "rep lacement" launch vehicle; and 3) Fulfill about 140 on-orbit mission requirements. It had tactical sensors, two unproven communication links, numerous next-gen eration single- string componen ts (e.g., h igh-efficiency propulsion system, thin-film so lar arrays, low-power versatile star camera) , and autonomous softw are to mak e the system more friendly and familiar to Tactical, rather than Spacecraf t Op erators. However, the mission was as mu ch about the implementation as it w as about the components. TacSat-2 was designed for and emp loyed with a different concept of operations ( CONOPS) than tradition al N ational Operational Assets. It w as designed to be th e fir st-ev er Clo se Space Support platform and operated in a manner more analogous to Close Air Support aircraf t than to tr aditional spacecraft. Therefore, th e primary objective of the TacSat-2 mission was to use th e TacSat-2 system to id entify those parts of the spacecr aft, ground system, and CON OPS

  19. NASA's Space Launch System: A New Opportunity for CubeSats

    NASA Technical Reports Server (NTRS)

    Hitt, David; Robinson, Kimberly F.; Creech, Stephen D.

    2016-01-01

    Designed for human exploration missions into deep space, NASA's Space Launch System (SLS) represents a new spaceflight infrastructure asset, enabling a wide variety of unique utilization opportunities. Together with the Orion crew vehicle and ground operations at NASA's Kennedy Space Center in Florida, SLS is a foundational capability for NASA's Journey to Mars. From the beginning of the SLS flight program, utilization of the vehicle will also include launching secondary payloads, including CubeSats, to deep-space destinations. Currently, SLS is making rapid progress toward readiness for its first launch in 2018, using the initial configuration of the vehicle, which is capable of delivering 70 metric tons (t) to Low Earth Orbit (LEO). On its first flight, Exploration Mission-1, SLS will launch an uncrewed test flight of the Orion spacecraft into distant retrograde orbit around the moon. Accompanying Orion on SLS will be 13 CubeSats, which will deploy in cislunar space. These CubeSats will include not only NASA research, but also spacecraft from industry and international partners and potentially academia. Following its first flight and potentially as early as its second, which will launch a crewed Orion spacecraft into cislunar space, SLS will evolve into a more powerful configuration with a larger upper stage. This configuration will initially be able to deliver 105 t to LEO and will continue to be upgraded to a performance of greater than 130 t to LEO. While the addition of the more powerful upper stage will mean a change to the secondary payload accommodations from Block 1, the SLS Program is already evaluating options for future secondary payload opportunities. Early discussions are also already underway for the use of SLS to launch spacecraft on interplanetary trajectories, which could open additional opportunities for CubeSats. This presentation will include an overview of the SLS vehicle and its capabilities, including the current status of progress toward

  20. CryoSat-2 swath interferometric altimetry for mapping polar land ice terrain and elevation change

    NASA Astrophysics Data System (ADS)

    Gourmelen, N.; Escorihuela, M. J.; Foresta, L.; Shepherd, A.; Muir, A.; Hogg, A. E.; Roca, M.; Nagler, T.; Baker, S.; Drinkwater, M. R.

    2015-12-01

    Reference and repeat-observations of Glacier and Ice Sheet Margin (GISM) topography are critical to identify changes in ice thickness, provide estimates of mass gain or loss and thus quantify the contribution of the cryosphere to sea level change. The lack of such sustained observations was identified in the Integrated Global Observing Strategy (IGOS) Cryosphere Theme Report as a major shortcoming. Conventional altimetry measurements over GISMs exist, but coverage has been sparse and characterized by coarse ground resolution. Additionally, and more importantly, they proved ineffective in the presence of steep slopes, a typical feature of GISM areas. Since the majority of Antarctic and Greenland ice sheet mass loss is estimated to lie within 100 km from the coast, but only about 10% is surveyed, there is the need for more robust and dense observations of GISMs, in both time and space. The ESA Altimetry mission CryoSat aims at gaining better insight into the evolution of the Cryosphere. CryoSat's revolutionary design features a Synthetic Interferometric Radar Altimeter (SIRAL), with two antennas for interferometry. The corresponding SAR Interferometer (SARIn) mode of operation increases spatial resolution while resolving the angular origin of off-nadir echoes occurring over sloping terrain. The SARIn mode is activated over GISMs and the elevation for the Point Of Closest Approach (POCA) is a standard product of the CryoSat mission. Here we present, through a wide range of examples in Polar settings, a new approach for more comprehensively exploiting the SARIn mode of CryoSat and produce ice elevation and elevation change with enhanced spatial resolution compared to standard CryoSat elevation products. In this so-called CryoSat Swath SARIn (CSSARIn) approach, the signal beyond the POCA is analysed, leading to between 1 and 2 orders of magnitude more elevation measurements than conventional approaches, and providing elevation where conventional POCA fails. We will

  1. An investigation into using differential drag for controlling a formation of CubeSats

    NASA Astrophysics Data System (ADS)

    Horsley, M.

    2011-09-01

    As the SSA system upgrades its existing capabilities and adds new ones, the potential offered by inexpensive CubeSat-based systems is growing more attractive. The potential benefits of using CubeSats increase if they are operated in groups to form ‘virtual’ satellites, which have the same functionality of a much larger satellite, but at a fraction of the cost. This paper will investigate the feasibility of using differential aerodynamic forces to control a formation of CubeSats in order to form a virtual satellite. Unfortunately, due to third body gravitational forces, solar radiation pressure, and other perturbing forces, the satellites will drift apart if no control mechanism is employed to maintain the formation. However, providing for a control mechanism is difficult. Using a rocket engine is expensive, increases mission risk, and requires fuel to be carried in the rather limited volume available in a typical CubeSat. However, passive techniques that take advantage of the differential aerodynamic forces experienced by two spacecraft can be used to exert a modest amount of control over the formation. Techniques for doing this have been discussed in the literature. These techniques rely on a simple drag plate, and only allow modest control of the formation in the plane defined by the spacecrafts orbit. An alternative is to treat the drag plate as an aerodynamic control surface, much as is done with an aircraft. This technique allows the control surface to be oriented in a fully 3 dimensional fashion, allowing a greater range of control of the satellite formation. A challenge in treating the drag plate as a 3 dimensional control surface is that the equations of motion describing the relative motions of the satellites become fully coupled with their relative orientations. Thus, controlling the satellite formation by adjusting the relative orientations of the different satellites will require solving a fully coupled set of differential equations and devising a

  2. Captura de satélites durante a formação de Júpiter

    NASA Astrophysics Data System (ADS)

    Winter, O. C.; Vieira Neto, E.; Yokoyama, T.

    2003-08-01

    O planeta Jupiter apresenta um grande número de satélites irregulares. As características das órbitas destes objetos indicam que os mesmos não teriam se formado ao redor do planeta que se encontram. As teorias existentes são de que estes objetos teriam se formado em uma região distante do planeta e sua evolução dinâmica os teria levado a uma captura gravitacional pelo planeta. Tendo em vista que o processo de captura gravitacional sem efeitos dissipativos não produz uma captura permanente, estudamos o processo de captura durante o estágio de formação do planeta. Realizamos simulações numéricas para os casos de satélites prógrados e retrógrados que inicialmente se encontram ao redor de Jupiter com sua massa atual e então, evoluimos a integração voltando no tempo de modo que o planeta sofra uma redução em sua massa (de 100% para 10% de sua massa atual) e verificamos o instante em que o satélites escapa do planeta (quando sua energia do problema de dois corpos se torna positiva). Assim, analisando o problema inverso no tempo, obtivemos em qual estágio de formação de Jupiter aquele hipotético satélite teria sido capturado. Os resultados mostram que os satélites retrógrados são capturados assim que entram na região delimitada pela esfera de Hill do planeta, enquanto que os satélites prógrados só são capturados quando entram numa região bem mais próxima ao planeta, uma fração da esfera de Hill.

  3. A dominant negative mutation in the conserved RNA helicase motif 'SAT' causes splicing factor PRP2 to stall in spliceosomes.

    PubMed Central

    Plumpton, M; McGarvey, M; Beggs, J D

    1994-01-01

    To characterize sequences in the RNA helicase-like PRP2 protein of Saccharomyces cerevisiae that are essential for its function in pre-mRNA splicing, a pool of random PRP2 mutants was generated. A dominant negative allele was isolated which, when overexpressed in a wild-type yeast strain, inhibited cell growth by causing a defect in pre-mRNA splicing. This defect was partially alleviated by simultaneous co-overexpression of wild-type PRP2. The dominant negative PRP2 protein inhibited splicing in vitro and caused the accumulation of stalled splicing complexes. Immunoprecipitation with anti-PRP2 antibodies confirmed that dominant negative PRP2 protein competed with its wild-type counterpart for interaction with spliceosomes, with which the mutant protein remained associated. The PRP2-dn1 mutation led to a single amino acid change within the conserved SAT motif that in the prototype helicase eIF-4A is required for RNA unwinding. Purified dominant negative PRP2 protein had approximately 40% of the wild-type level of RNA-stimulated ATPase activity. As ATPase activity was reduced only slightly, but splicing activity was abolished, we propose that the dominant negative phenotype is due primarily to a defect in the putative RNA helicase activity of PRP2 protein. Images PMID:8112301

  4. Small Aircraft Transportation System (SATS): A Collaborative Effort Between Nebraska EPSCoR and NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Implementing SATS in Nebraska will require a number of changes, both technical and administrative. SATS will require major improvements in the infrastructure of Nebraska airports. Improving airport infrastructure so that it can accommodate SATS is first and most obvious goal. A second goal is to make airports financially sustainable over the long term with limited federal assistance. A third goal, closely related to the second, is to link the implementation of SATS with anticipated local economic growth. This can leverage local funds without tax increases, enhance the equity of the finance approach, improve planning of facility size, and reduce long-term per unit cost. Many of these goals are national issues, and presumably federal policy will determine how these goals are addressed. This study examines several financing options and discusses their ease of application to Nebraska's airports.

  5. The International Space Station as a Launch Platform for CubeSats to Study Space Weather

    NASA Astrophysics Data System (ADS)

    Fish, C. S.; Swenson, C.; Sojka, J. J.

    2011-12-01

    The Ionosphere-Thermosphere-Mesosphere (ITM) region (80 to 250 km) is the boundary between the sensible atmosphere of the Earth and space. This region receives energy and momentum contributions from the sun in the form of solar ultra-violet light and electromagnetic energy coupled via the earth's magnetosphere. The ITM region also receives energy and momentum from the lower atmosphere via waves that break and terminate turbulently in this beach-like region. The various processes, acting both as system drivers and feedback elements in the ITM region, are still poorly understood and the weather of the ITM region cannot be predicted. It is also the area where satellite drag ensures a quick end to satellite lifetimes and it has thus become known as the "inaccessible region." As the terrestrial populations wrestle with the question of "change" (global, climate, etc), our need to continue making long-term measurements is crucial, but is hampered by cost and launch opportunities for even smaller dedicated satellites. The ITM region itself has been identified as a region where almost un-measurable atmospheric changes have very measurable consequences. The International Space Station (ISS), orbiting just above this "inaccessible region", is an ideal platform from which CubeSats can be launched to study the region below. It could become a permanent launch platform for regular or responsive deployment of the small satellite fleet. For example, a group of satellites could be launched in response to a storm or an important lower atmospheric event that has been identified as occurring. Such satellites would last approximately one year before re-entering the upper atmosphere. It is an ideal location from which to routinely launch probes into the inaccessible region below to maintain a long term climate observational capability. The advantage of the ISS is that deployments of these small satellites is not contingent on finding a suitable ground based launch opportunity, whose

  6. SCION: CubeSat Mission Concept to Observe Midlatitude Small-Scale Irregularities and Scintillation

    NASA Astrophysics Data System (ADS)

    Heine, T.; Moldwin, M.

    2014-12-01

    The SCintillation and Ionospheric Occultation NanoSats (SCION) mission concept is to deploy two low-cost CubeSat spacecraft that maintain a separation distance <1 km to measure scintillation and associated small-scale density irregularities in the midlatitude ionosphere. Each spacecraft is equipped with a dual frequency GPS receiver to measure total electron content (TEC) and the S4 scintillation index along raypaths from the receiver to the GPS constellation. Scintillation causing small-scale density irregularities are increasingly observed in the vicinity of large TEC gradients associated with storm enhanced density (SED) regions. Detection of irregularities of the scale that cause GPS and VHF scintillation has previously relied on assumptions about their structural stability and drift speed. Space-based, multipoint observations would provide broad, regional coverage and disambiguation of temporal and spatial density fluctuations in order to detect small-scale irregularities without these assumptions.

  7. Influence of multiple scattering on CloudSat measurements in snow: A model study

    NASA Astrophysics Data System (ADS)

    Matrosov, Sergey Y.; Battaglia, Alessandro

    2009-06-01

    The effects of multiple scattering on larger precipitating hydrometers have an influence on measurements of the spaceborne W-band (94 GHz) CloudSat radar. This study presents initial quantitative estimates of these effects in “dry” snow using radiative transfer calculations for appropriate snowfall models. It is shown that these effects become significant (i.e., greater than approximately 1 dB) when snowfall radar reflectivity factors are greater than about 10-15 dBZ. Reflectivity enhancement due to multiple scattering can reach 4-5 dB in heavier stratiform snowfalls. Multiple scattering effects counteract signal attenuation, so the observed CloudSat reflectivity factors in snowfall could be relatively close to the values that would be observed in the case of single scattering and the absence of attenuation.

  8. Economic Analysis of a Laser-Powered, Global Small Aerospacecraft Transportation System (G-SATS)

    NASA Astrophysics Data System (ADS)

    Walton, David; List, George; Myrabo, Leik N.

    2005-04-01

    A first-order economic analysis is performed for a revolutionary transport technology intended for hypersonic world travel — powered by laser energy beamed from satellite solar power stations, with relay mirrors in low Earth orbit. A fleet of 1-person to 5-person, `tractor-beam' lightcraft will enable direct port-to-port (no refueling) trips, half-way around the globe in under an hour — riding suborbital boost-glide trajectories through space. Estimates are presented of vehicle size, ridership, revenues, fleet size, capital, operating and maintenance costs, and expected profitability for a lightcraft-based global transportation system called G-SATS. On a net present value basis, over a 20-year time span, G-SATS should have a profit margin of over 20% — implying not only the ability to be profitable, but also a potential market penetrability that goes well beyond the conservative assumptions made in this analysis.

  9. The Iodine Satellite (iSAT) Hall Thruster Demonstration Mission Concept and Development

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.; Polzin, Kurt A.; Calvert, Derek; Kamhawi, Hani

    2014-01-01

    The use of iodine propellant for Hall thrusters has been studied and proposed by multiple organizations due to the potential mission benefits over xenon. In 2013, NASA Marshall Space Flight Center competitively selected a project for the maturation of an iodine flight operational feed system through the Technology Investment Program. Multiple partnerships and collaborations have allowed the team to expand the scope to include additional mission concept development and risk reduction to support a flight system demonstration, the iodine Satellite (iSAT). The iSAT project was initiated and is progressing towards a technology demonstration mission preliminary design review. The current status of the mission concept development and risk reduction efforts in support of this project is presented.

  10. Sistema Planeta-Satélite. Simulación orbital y potenciales gravitatorios

    NASA Astrophysics Data System (ADS)

    Medina, C.; Carrillo, M.

    Se presenta un programa (desarrollado en Quick Basic 4.5) que simula, en tres dimensiones, el movimiento orbital de un satélite (o luna) alrededor de un planeta, al tiempo que calcula y grafica, en un plano, el potencial gravitatorio del sistema en función de la distancia al planeta. Para la simulación orbital, se emplea la matriz de transformación entre el sistema del planeta y el plano orbital. Para el cálculo y graficación del potencial se aplica un desarrollo en serie hasta el segundo orden, que da cuenta del efecto de achatamiento de los polos, en caso de que éste exista. Las longitudes de los ejes del planeta, la masa de éste y del satélite, sus tamaños aparentes, y los parámetros orbitales son introducidos por el usuario.

  11. The Small Aircraft Transportation System (SATS): Research Collaborations with the NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Tarry, Scott E.; Bowen, Brent D.; Nickerson, Jocelyn S.

    2002-01-01

    The aviation industry is an integral part of the world s economy. Travelers have consistently chosen aviation as their mode of transportation as it is reliable, time efficient and safe. The out- dated Hub and Spoke system, coupled with high demand, has led to delays, cancellations and gridlock. NASA is developing innovative solutions to these and other air transportation problems. This research is being conducted through partnerships with federal agencies, industry stakeholders, and academia, specifically the University of Nebraska at Omaha. Each collaborator is pursuing the NASA General Aviation Roadmap through their involvement in the expansion of the Small Aircraft Transportation System (SATS). SATS will utilize technologically advanced small aircraft to transport travelers to and from rural and isolated communities. Additionally, this system will provide a safe alternative to the hub and spoke system, giving more time to more people through high-speed mobility and increased accessibility.

  12. Test and On-Orbit Experiences of FalconSAT-3

    NASA Astrophysics Data System (ADS)

    Saylor, W. W.; France, M. E. B.

    2008-08-01

    The fundamental objectives of the capstone design project in the Department of Astronautics at the United States Air Force Academy (USAFA) are for cadets to learn important engineering lessons by executing a real space mission on a Department of Defense-funded satellite project. FalconSAT-3 is a 50 kg, gravity gradient-stabilized designed and built by cadets and launched March 2007 on the first ESPA (Enhanced extended launch vehicle Satellite Payload Adapter) mission. FalconSAT-3 was one of six satellites integrated onto the launch vehicle and the nature of the mission made it that the satellite was subject to the full formality of testing requirements. Two successive gravity gradient booms failed either design requirements or environmental testing; design requirements grew dramatically during the design phase; ambiguous thermal vacuum test results led to uncertainty at launch; and after launch it was not possible to contact the satellite for several weeks.

  13. Design and Functional Validation of a Mechanism for Dual-Spinning CubeSats

    NASA Technical Reports Server (NTRS)

    Peters, Eric; Dave, Pratik; Kingsbury, Ryan; Marinan, Anne; Wise, Evan; Pong, Chris; Prinkey, Meghan; Cahoy, Kerri; Miller, David W.; Sklair, Devon

    2014-01-01

    The mission of the Micro-sized Microwave Atmospheric Satellite (MicroMAS) is to collect useful atmospheric images using a miniature passive microwave radiometer payload hosted on a low-cost CubeSat platform. In order to collect this data, the microwave radiometer payload must rotate to scan the ground-track perpendicular to the satellite's direction of travel. A custom motor assembly was developed to facilitate the rotation of the payload while allowing the spacecraft bus to remained fixed in the local-vertical, local-horizontal (LVLH) frame for increased pointing accuracy. This paper describes the mechanism used to enable this dual-spinning operation for CubeSats, and the lessons learned during the design, fabrication, integration, and testing phases of the mechanism's development lifecycle.

  14. Terrestrial gamma-ray flashes monitor demonstrator on CubeSat

    NASA Astrophysics Data System (ADS)

    Dániel, V.; Pína, L.; Inneman, A.; Zadražil, V.; Báča, T.; Platkevič, M.; Stehlíková, V.; Nentvich, O.; Urban, M.

    2016-09-01

    The CubeSat mission with the demonstrator of miniaturized X-ray telescope is presented. The paper presents one of the mission objectives of using the instrument for remote sensing of the Terrestrial Gamma-ray Flashes (TGFs). TGFs are intense sources of gamma-rays associated with lightning bolt activity and tropical thunderstorms. The measurement of TGFs exists and was measured by sounding rockets, high altitude balloons or several satellite missions. Past satellite missions were equipped with different detectors working from 10 keV up to 10 MeV. The RHESSI mission spectrum measurement of TGFs shows the maximum counts per second around 75 keV. The used detectors were in general big in volume and cannot be utilized by the CubeSat mission. The presented CubeSat is equipped with miniaturized X-ray telescope using the Timepix non-cooled pixel detector. The detector works between 3 and 60 keV in counting mode (dosimetry) or in spectrum mode with resolution 5 keV. The wide-field X-ray "Lobster-eye" optics/collimator (depending on energy) is used with a view angle of 3 degrees for the source location definition. The UV detectors with FOV 30 degrees and 1.5 degrees are added parallel with the optic as a part of the telescope. The telescope is equipped with software distinguishing between the photons and other particles. Using this software the TGF's detection is possible also in the field of South Atlantic anomaly. For the total ionization dose, the additional detector is used based on Silicone (12-60 keV) and CdTe (20 keV - 1 MeV). The presented instruments are the demonstrators suitable also for the astrophysical, sun and moon observation. The paper shows the details of TGF's observation modes, detectors details, data processing and handling system and mission. The CubeSat launch is planned to summer 2016.

  15. EarthSat spring wheat yield system test 1975, appendix 4

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A computer system is presented which processes meteorological data from both ground observations and meteorologic satellites to define plant weather aspects on a four time per day basis. Plant growth stages are calculated and soil moisture profiles are defined by the system. The EarthSat system assesses plant stress and prepares forecasts of end-of-year yields. The system was used to forecast spring wheat yields in the upper Great Plains states. Hardware and software documentation is provided.

  16. Calibration And Validation Of CryoSat-2 Low Resolution Mode Data

    NASA Astrophysics Data System (ADS)

    Naeije, M.; Schrama, E.; Scharroo, R.

    2011-02-01

    Running ahead of the continuously growing need for operational use of sea level products, TUDelft started off the Radar Altimeter Database System RADS many years ago. This system attends to a global international sea- level service. It supports, on one hand, science, like studies on ocean circulation, El Nio, sea level change, and ice topography, and on the other hand (offshore) operations, like delivery of ocean current information, wind and wave statistics, ice detection and ice classification. At present, the database is used by a large scientific community throughout the world, and is daily maintained and developed by Altimetrics LLC, TUDelft and NOAA. It contains all historic altimeter data, and now has to be up- dated with the data from ESAs ice mission CryoSat-2, which was launched successfully in April 2010. These new data are important to augment the data set and by that to improve the estimates of sea level change and its contributors. For this the data have to be validated and calibrated, necessary corrections added and improved (including modelling of corrections that are not directly available from the CryoSat-2 platform), and the orbit ac- curacy verified and if possible the orbits brushed up. Subsequently, value-added ocean and ice products need to be developed in synergy with all the other satellite altimeter data. During the commissioning phase we primarily looked at the sanity of the available level-1b and level-2 Low Resolution Mode (LRM) data. Here, for the 2011 CryoSat Validation Workshop, we present the results of our calibration and validation of LRM L2 data by internal comparison of CryoSat-2 and external comparison with other satellites. We have established a range bias of 3.77 (measurement range too long) and a timing bias of 8.2ms (measurement range too late).

  17. MightySat II.1 Hyperspectral Imager: Summary of On-Orbit Performance

    DTIC Science & Technology

    2002-01-01

    system is composed of a telescope and a re-imaging system4 (Figure 1). The telescope is a 165mm clear aperture Ritchey - Cretien design.3 The system...tolerances. Camera Lens Assembly Interferometer Telescope Figure 1: Exploded view of the Fourier Transform Hyperspectral Instrument on-board MightySat II.1...launch (as of 2 July 2001). The temperature sensors are located on or near the telescope (HSITT), interferometer (HSIIT), and the camera (HSICT). All

  18. Application of CryoSat-2 altimetry data for river analysis and modelling

    NASA Astrophysics Data System (ADS)

    Schneider, Raphael; Nygaard Godiksen, Peter; Villadsen, Heidi; Madsen, Henrik; Bauer-Gottwein, Peter

    2017-02-01

    Availability of in situ river monitoring data, especially of data shared across boundaries, is decreasing, despite growing challenges for water resource management across the entire globe. This is especially valid for the case study of this work, the Brahmaputra Basin in South Asia. Commonly, satellite altimeters are used in various ways to provide information about such river basins. Most missions provide virtual station time series of water levels at locations where their repeat orbits cross rivers. CryoSat-2 is equipped with a new type of altimeter, providing estimates of the actual ground location seen in the reflected signal. It also uses a drifting orbit, challenging conventional ways of processing altimetry data to river water levels and their incorporation in hydrologic-hydrodynamic models. However, CryoSat-2 altimetry data provides an unprecedentedly high spatial resolution. This paper suggests a procedure to (i) filter CryoSat-2 observations over rivers to extract water-level profiles along the river, and (ii) use this information in combination with a hydrologic-hydrodynamic model to fit the simulated water levels with an accuracy that cannot be reached using information from globally available digital elevation models (DEMs) such as from the Shuttle Radar Topography Mission (SRTM) only. The filtering was done based on dynamic river masks extracted from Landsat imagery, providing spatial and temporal resolutions high enough to map the braided river channels and their dynamic morphology. This allowed extraction of river water levels over previously unmonitored narrow stretches of the river. In the Assam Valley section of the Brahmaputra River, CryoSat-2 data and Envisat virtual station data were combined to calibrate cross sections in a 1-D hydrodynamic model of the river. The hydrologic-hydrodynamic model setup and calibration are almost exclusively based on openly available remote sensing data and other global data sources, ensuring transferability of

  19. Enhanced Arctic Mean Sea Surface and Mean Dynamic Topography including retracked CryoSat-2 Data

    NASA Astrophysics Data System (ADS)

    Andersen, O. B.; Jain, M.; Stenseng, L.; Knudsen, P.

    2014-12-01

    A reliable mean sea surface (MSS) is essential to derive a good mean dynamic topography (MDT) and for the estimation of short and long-term changes in the sea surface. The lack of satellite radar altimetry observations above 82 degrees latitude means that existing mean sea surface models have been unreliable in the Arctic Ocean. We here present the latest DTU mean sea surface and mean dynamic topography models combining conventional altimetry with retracked CryoSat-2 data to improve the reliability in the Arctic Ocean. For the derivation of a mean dynamic topography the ESA GOCE derived geoid model have been used to constrain the longer wavelength. We present the retracking of C2 SAR data using various retrackes and how we have been able to combine data from various retrackers under various sea ice conditions. DTU13MSS and DTU13MDT are the newest state of the art global high-resolution models including CryoSat-2 data to extend the satellite radar altimetry coverage up to 88 degrees latitude and through combination with a GOCE geoid model completes coverage all the way to the North Pole. Furthermore the SAR and SARin capability of CryoSat-2 dramatically increases the amount of useable sea surface returns in sea-ice covered areas compared to conventional radar altimeters like ENVISAT and ERS-1/2. With the inclusion of CryoSat-2 data the new mean sea surface is improved by more than 20 cm above 82 degrees latitude compared with the previous generation of mean sea surfaces.

  20. CryoSat Level1b SAR/SARin: quality improvements towards BaselineC

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; Bouzinac, Catherine; Tagliani, Nicolas; Parrinello, Tommaso

    2014-05-01

    CryoSat was launched on the 8th April 2010 and it is the first European ice mission dedicated to monitoring precise changes in the thickness of polar ice sheets and floating sea ice over a 3-year period. Cryosat carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach a significantly improved along track resolution with respect to traditional pulse-width limited altimeters. CryoSat is the first altimetry mission operating in SAR mode and continuous improvement in the Level1 Instrument Processing Facility (IPF1) are being identified, tested and validated in order to improve the quality of the Level1b products. Towards the release of the BaselineC of the CryoSat Level1b SAR/SARin products, that is expected during 2014, several improvements have been identified: • a datation bias of about -0.5195 ms will be corrected • a range bias of about -0.6730 m will be corrected • the waveform length in the Level1b product will be doubled with respect to BaselineB • improved processing for 1Hz echoes to have sharper waveforms • surface sample stack weighting to filter out the single look echoes acquired at highest look angle, that results in a sharpening of the 20Hz waveforms This poster details the main improvements that are foreseen to be included in the CryoSat Level1b SAR/SARin products in BaselineC.

  1. CloudSat system engineering: techniques that point to a future success

    NASA Technical Reports Server (NTRS)

    Basilio, R. R.; Boain, R. J.; Lam, T.

    2002-01-01

    Over the past three years the CloutSat Project, a NASA Earth System Science Pathfinder mission to provide from space the first global survey of cloud profiles and cloud physical properties, has implemented a successful project system engineering approach. Techniques learned through heuristic reasoning of past project events and professional experience were applied along with select methods recently touted to increase effectiveness without compromising effiency.

  2. CanSat Competition: Contributing to the Development of NASA's Vision for Robotic Space Exploration

    NASA Technical Reports Server (NTRS)

    Berman, Joshua; Berman, Timothy; Billheimer, Thomas; Biclmer. Elizabeth; Hood, Stuart; Neas, Charles

    2007-01-01

    CanSat is an international student design-build-launch competition organized by the American Astronautical Society (AAS) and American Institute of Aeronautics and Astronautics (AIAA). The competition is also sponsored by the Naval Research Laboratory (NRL) and the National Aeronautics and Space Administration (NASA). The CanSat competition is designed for college, university and high school students wanting to participate in an applicable space-related competition. The objective of the CanSat competition is to complete space exploration missions by designing a specific system for a small sounding rocket payload which will follow and perform to a specific set of rules and guidelines for each year's competition. The competition encompasses a complete life-cycle of one year which includes all phases of design, integration, testing, judging and competition. The mission guidelines are based from space exploration missions and include bonus requirement options which teams may choose to participate in. The fundamental goal of the competition is to educate future engineers and scientists. This is accomplished by students applying systems engineering practices to a development project that incorporates an end-to-end life cycle, from requirements analysis, through preliminary design, integration and testing, an actual flight of the CanSat, and concluding with a post-mission debrief. This is done specifically with space related missions to bring a unique aspect of engineering and design to the competition. The competition has been progressing since its creation in 2005. The competition was originally meant to purely convey the engineering and design process to its participants, but through many experiences the competition has also undergone a learning experience with respect to systems engineering process and design. According

  3. CryoSat-2 Arctic Sea-Ice Thickness: Uncertainties and Outlook

    NASA Astrophysics Data System (ADS)

    Ricker, R.; Hendricks, S.; Helm, V.; Haas, C.; Davidson, M.

    2014-12-01

    The CryoSat-2 satellite is in the 4th year of its mission. It has collected a unique altimetry dataset with higher spatial resolution and a better coverage of Arctic sea ice than any previous radar altimeter mission. The along-track sharpened footprint allows resolving fine-scale features of the ice pack and the examination of retrievable information from the SAR waveforms is a field of ongoing research. Different methods can be applied to CryoSat-2 data: threshold retrackers that use the leading edge; or fitted forward models, which are applied to full waveforms. The uncertainty of these methods propagates into the uncertainty of the final sea-ice thickness estimate via the freeboard to thickness conversion. Theoretical considerations show that the magnitude of uncertainties in the radar retracking may be a major if not dominating contribution to the uncertainty budget of sea-ice thickness retrieval from CryoSat-2. We present a break-down of the uncertainty budget of CryoSat-2 Arctic sea-ice thickness of the threshold retracker based sea-ice thickness data product of the Alfred Wegener Institute. We discuss the differences in the radar waveform properties and the identification of leads in first-year and multi-year ice covered areas with the aim to mitigate ice type dependent biases. Though threshold retrackers are prone to a simplistic interpretation of the SAR waveforms we investigate the potential of this fast and robust method to retrieve additional physical properties at the sea ice surface.

  4. Cal/Val activities for DubaiSat-2 performance assessment

    NASA Astrophysics Data System (ADS)

    Bushahab, A.; Al-Mansoori, S.; Al-Suwaidi, K.; Al Matroushi, Hessa; Al-Tunaiji, E.; Al Shamsi, Meera

    2014-10-01

    Emirates Institution for Advanced Science and Technology (EIAST) was established by the Dubai Government in 2006. After three years of working together with Satrec Initiative (South Korea), EIAST was able to launch DubaiSat-1 on the 29th of July 2009. Building on the success of DubaiSat-1 and the roll out of the knowledge transfer program, UAE engineers were involved in almost 70% of the total build and design of DubaiSat-2. Targeting the commercial market, DubaiSat-2 was launched on the 21st of November 2013 for capturing 1-meter resolution images. The 1st Cal/Val phase was the most critical phase in the satellite life-time, where most of the initial measurements took place. This phase extended over the period of 25/11/2013 till 12/12/2013. Moreover, this phase included most of the relative calibration tasks, color balancing and band matching. 2nd Cal/Val phase included most of the debugging and the pointing accuracy calibration tests. This phase extended over the period of 11/02/2014 till 09/03/2014. This phase emphasized on the calibration of the pointing accuracy. The 3rd Cal/Val phase included fine tuning for the Gyro system to further increase the stability of the satellite and thus improve the pointing accuracy. Moreover, new techniques were implemented to the Pan-Sharpening and to the MTF compensation procedures to enhance the final product. This phase extended over the period of 04/05/2014 till 21/05/2014.

  5. FalconSAT-7: Towards Rapidly Deployable Space-Based Surveillance

    DTIC Science & Technology

    2013-09-01

    the flight model for launch sometime in 2015. REFERENCES 1. Fresnel , M. A., Memoire sur la diffraction de la lumiere, Memoires de l’Academie...membrane solar telescope to be deployed from a 3U CubeSat in LEO. The primary optic is a 0.2m photon sieve – a diffractive element consisting of...size of monolithic (or even segmented) reflectors that can be put in orbit. Ensuring a diffraction limited surface is one issue, but more fundamentally

  6. CubeSat Packaged Electrospray Thruster Evaluation for Enhanced Operationally Responsive Space Capabilities

    DTIC Science & Technology

    2011-03-24

    These satellites can perform many missions including: close formation flying with other CubeSats, and possible docking with a large satellite to...in 2008 to fly on the NASA LISA mission. LISA, the Laser Interferometer Space Antenna, is a joint NASA–ESA mission to observe astrophysical and...for mass spectrometry of large organic molecules popularized the technology and made components such as needles or other components readily

  7. SkySat-1: very high-resolution imagery from a small satellite

    NASA Astrophysics Data System (ADS)

    Murthy, Kiran; Shearn, Michael; Smiley, Byron D.; Chau, Alexandra H.; Levine, Josh; Robinson, M. Dirk

    2014-10-01

    This paper presents details of the SkySat-1 mission, which is the first microsatellite-class commercial earth- observation system to generate sub-meter resolution panchromatic imagery, in addition to sub-meter resolution 4-band pan-sharpened imagery. SkySat-1 was built and launched for an order of magnitude lower cost than similarly performing missions. The low-cost design enables the deployment of a large imaging constellation that can provide imagery with both high temporal resolution and high spatial resolution. One key enabler of the SkySat-1 mission was simplifying the spacecraft design and instead relying on ground- based image processing to achieve high-performance at the system level. The imaging instrument consists of a custom-designed high-quality optical telescope and commercially-available high frame rate CMOS image sen- sors. While each individually captured raw image frame shows moderate quality, ground-based image processing algorithms improve the raw data by combining data from multiple frames to boost image signal-to-noise ratio (SNR) and decrease the ground sample distance (GSD) in a process Skybox calls "digital TDI". Careful qual-ity assessment and tuning of the spacecraft, payload, and algorithms was necessary to generate high-quality panchromatic, multispectral, and pan-sharpened imagery. Furthermore, the framing sensor configuration en- abled the first commercial High-Definition full-frame rate panchromatic video to be captured from space, with approximately 1 meter ground sample distance. Details of the SkySat-1 imaging instrument and ground-based image processing system are presented, as well as an overview of the work involved with calibrating and validating the system. Examples of raw and processed imagery are shown, and the raw imagery is compared to pre-launch simulated imagery used to tune the image processing algorithms.

  8. Fate and transport of carbamazepine in soil aquifer treatment (SAT) infiltration basin soils.

    PubMed

    Arye, Gilboa; Dror, Ishai; Berkowitz, Brian

    2011-01-01

    The transport and fate of the pharmaceutical carbamazepine (CBZ) were investigated in the Dan Region Reclamation Project (SHAFDAN), Tel-Aviv, Israel. Soil samples were taken from seven subsections of soil profiles (150 cm) in infiltration basins of a soil aquifer treatment (SAT) system. The transport characteristics were studied from the release dynamics of soil-resident CBZ and, subsequently, from applying a pulse input of wastewater containing CBZ. In addition, a monitoring study was performed to evaluate the fate of CBZ after the SAT. Results of this study indicate adsorption, and consequently retardation, in CBZ transport through the top soil layer (0-5 cm) and to a lesser extent in the second layer (5-25 cm), but not in deeper soil layers (25-150 cm). The soluble and adsorbed fractions of CBZ obtained from the two upper soil layers comprised 45% of the total CBZ content in the entire soil profile. This behavior correlated to the higher organic matter content observed in the upper soil layers (0-25 cm). It is therefore deduced that when accounting for the full flow path of CBZ through the vadose zone to the groundwater region, the overall transport of CBZ in the SAT system is essentially conservative. The monitoring study revealed that the average concentration of CBZ decreased from 1094 ± 166 ng L⁻¹ in the recharged wastewater to 560 ± 175 ng L⁻¹ after the SAT. This reduction is explained by dilution of the recharged wastewater with resident groundwater, which may occur as it flows to active reclamation wells.

  9. An Optimum Space-to-Ground Communication Concept for CubeSat Platform Utilizing NASA Space Network and Near Earth Network

    NASA Technical Reports Server (NTRS)

    Wong, Yen F.; Kegege, Obadiah; Schaire, Scott H.; Bussey, George; Altunc, Serhat; Zhang, Yuwen; Patel, Chitra

    2016-01-01

    National Aeronautics and Space Administration (NASA) CubeSat missions are expected to grow rapidly in the next decade. Higher data rate CubeSats are transitioning away from Amateur Radio bands to higher frequency bands. A high-level communication architecture for future space-to-ground CubeSat communication was proposed within NASA Goddard Space Flight Center. This architecture addresses CubeSat direct-to-ground communication, CubeSat to Tracking Data Relay Satellite System (TDRSS) communication, CubeSat constellation with Mothership direct-to-ground communication, and CubeSat Constellation with Mothership communication through K-Band Single Access (KSA).A Study has been performed to explore this communication architecture, through simulations, analyses, and identifying technologies, to develop the optimum communication concepts for CubeSat communications. This paper will present details of the simulation and analysis that include CubeSat swarm, daughter shipmother ship constellation, Near Earth Network (NEN) S and X-band direct to ground link, TDRS Multiple Access (MA) array vs Single Access mode, notional transceiverantenna configurations, ground asset configurations and Code Division Multiple Access (CDMA) signal trades for daughter mother CubeSat constellation inter-satellite crosslink. Results of Space Science X-band 10 MHz maximum achievable data rate study will be summarized. Assessment of Technology Readiness Level (TRL) of current CubeSat communication technologies capabilities will be presented. Compatibility test of the CubeSat transceiver through NEN and Space Network (SN) will be discussed. Based on the analyses, signal trade studies and technology assessments, the functional design and performance requirements as well as operation concepts for future CubeSat end-to-end communications will be derived.

  10. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterizations

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Clark, S.; Fitz-Coy, N.; Huynh, T.; Opiela, J.; Polk, M.; Roebuck, B.; Rushing, R.; Sorge, M.; Werremeyer, M.

    2013-01-01

    The goal of the DebriSat project is to characterize fragments generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 s US Navy Transit satellite. There are three phases to this project: the design and fabrication of DebriSat - an engineering model representing a modern, 60-cm/50-kg class LEO satellite; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area-to-mass ratio, density, shape, material composition, optical properties, and radar cross-section distributions, will be used to supplement the DoD s and NASA s satellite breakup models to better describe the breakup outcome of a modern satellite.

  11. ASPECT spectral imaging satellite proposal to AIDA/AIM CubeSat payload

    NASA Astrophysics Data System (ADS)

    Kohout, Tomas; Näsilä, Antti; Tikka, Tuomas; Penttilä, Antti; Muinonen, Karri; Kestilä, Antti; Granvik, Mikael; Kallio, Esa

    2016-10-01

    The Asteroid Spectral Imaging Mission (ASPECT) is a part of the Asteroid Impact Mission (AIM) project, and aims to study the composition of the Didymos binary asteroid and the efects of space weathering and shock metamorphism in order to gain understanding of the formation and evolution of the Solar System. The joint ESA/NASA Asteroid Impact Detection Assessment (AIDA) mission to binary asteroid Didymos consists of the Asteroid Impact Mission (AIM) by ESA and the Double Asteroid Redirection Test (DART) by NASA. DART is targeted to impact the Didymos secondary component (Didymoon) while AIM monitors the impact efects. This will demonstrate the use of a kinetic impactor to detect potentially hazardous asteroids. Both spacecraft will be launched in 2020 and will arrive to Didymos in 2022. The AIM mission will also include two or three CubeSats, which will be released in the Didymos system. This arrangement opens up a possibility for secondary scientifc experiments. ASPECT is one of the proposed CubeSat payloads. ASPECT is a 3U CubeSat equipped with a VIS-NIR spectral imager and it will be used to measure the spectral characteristics of the impact site before and after the DART impact, as the impactor should bring fresh material to the surface. This gives a unique opportunity to study space weathering and shock efects on asteroids.

  12. Micropulsed Plasma Thrusters for Attitude Control of a Low-Earth-Orbiting CubeSat

    NASA Technical Reports Server (NTRS)

    Gatsonis, Nikolaos A.; Lu, Ye; Blandino, John; Demetriou, Michael A.; Paschalidis, Nicholas

    2016-01-01

    This study presents a 3-Unit CubeSat design with commercial-off-the-shelf hardware, Teflon-fueled micropulsed plasma thrusters, and an attitude determination and control approach. The micropulsed plasma thruster is sized by the impulse bit and pulse frequency required for continuous compensation of expected maximum disturbance torques at altitudes between 400 and 1000 km, as well as to perform stabilization of up to 20 deg /s and slew maneuvers of up to 180 deg. The study involves realistic power constraints anticipated on the 3-Unit CubeSat. Attitude estimation is implemented using the q method for static attitude determination of the quaternion using pairs of the spacecraft-sun and magnetic-field vectors. The quaternion estimate and the gyroscope measurements are used with an extended Kalman filter to obtain the attitude estimates. Proportional-derivative control algorithms use the static attitude estimates in order to calculate the torque required to compensate for the disturbance torques and to achieve specified stabilization and slewing maneuvers or combinations. The controller includes a thruster-allocation method, which determines the optimal utilization of the available thrusters and introduces redundancy in case of failure. Simulation results are presented for a 3-Unit CubeSat under detumbling, pointing, and pointing and spinning scenarios, as well as comparisons between the thruster-allocation and the paired-firing methods under thruster failure.

  13. "SeismoSAT" project results in connecting seismic data centres via satellite

    NASA Astrophysics Data System (ADS)

    Pesaresi, Damiano; Lenhardt, Wolfgang; Rauch, Markus; Živčić, Mladen; Steiner, Rudolf; Bertoni, Michele; Delazer, Heimo

    2016-04-01

    Since 2002 the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Udine (Italy), the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Vienna (Austria), and the Agencija Republike Slovenije za Okolje (ARSO) in Ljubljana (Slovenia) are collecting, analysing, archiving and exchanging seismic data in real time. Up to now the data exchange between the seismic data centres relied on internet: this however was not an ideal condition for civil protection purposes, since internet reliability is poor. For this reason, in 2012 the Protezione Civile della Provincia Autonoma di Bolzano in Bolzano (Italy) joined OGS, ZAMG and ARSO in the Interreg IV Italia-Austria project "SeismoSAT" (Progetto SeismoSAT, 2014) aimed in connecting the seismic data centres in real time via satellite. As already presented in the past, the general technical schema of the project has been outlined, data bandwidths and monthly volumes required have been quantified, the common satellite provider has been selected and the hardware has been purchased and installed. Right before the end of its financial period, the SeismoSAT project proved to be successful guaranteeing data connection stability between the involved data centres during an internet outage.

  14. Sea surface retracking and classification of CryoSat-2 altimetry observations in the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Stenseng, L.; Piccioni, G.; Andersen, O. B.; Knudsen, P.

    2015-12-01

    In this study we present the retracking and classification methods for CryoSat-2 SAR waveforms, developed for the determination of sea surface heights in the Arctic Ocean. The obtained sea surface heights (SSH) are used to decrease the gap in satellite observations from 82 degrees North to 88 degrees North in the DTU15 mean sea surface (MSS) and mean dynamic topography (MDT).Radar altimetry satellites has observed the sea surface for more than 25 years and thereby obtain data to determine accurate MSSs and estimate sea level trends related to climate changes. In combination with the improvements of global geoids it has furthermore provided an opportunity to improve the MDT related to ocean currents.After the launch of CryoSat-2 in 2010 the coverage was increased dramatically while the introduction of the synthetic aperture radar (SAR) and SAR interferometry (SARin) mode increased the amount of useful echoes in the Arctic Ocean. The new types of radar observation modes have been investigated and methods to retrack and classify the waveforms have been implemented in LARS the advanced retracking system (LARS). Finally the SSH observations obtained from CryoSat-2 with LARS is merged with previous satellite radar altimetry data to derive the DTU15 MSS.

  15. Cloud Features Detected by MODIS But Not by CloudSat and CALIOP

    NASA Technical Reports Server (NTRS)

    Chan, Mark Aaron; Comiso, Josefino C.

    2011-01-01

    The ability to characterize the global cloud cover from space has been greatly enhanced by the availability of MODIS, CloudSat, and CALIOP data. The three sensors provide good complementary information about clouds. In this study, we investigated unexpected observations of certain types of clouds apparent in the MODIS data but not detected by CloudSat and CALIOP. Several examples are presented and generally these undetected clouds are geometrically thin, low-level clouds. In particular, they are located in the Arctic region and have optical thicknesses of less than 14, top height altitudes of below 2.5 km, and layer thickness of less than 1 km. CloudSat may miss such low-level clouds because of its coarse vertical resolution of about 500 m and it has limited sensitivity near the surface. Unexpectedly, CALIOP with a much higher vertical resolution of 30 m also misses these clouds and this is due to the cloud s geometrically thin nature and surface proximity.

  16. Multidirectional Cosmic Ray Ion Detector for Deep Space CubeSats

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.

    2016-01-01

    Understanding the nature of anisotropy of solar energetic protons (SEPs) and galactic cosmic ray (GCR) fluxes in the interplanetary medium is crucial in characterizing time-dependent radiation exposure in interplanetary space for future exploration missions. NASA Glenn Research Center has proposed a CubeSat-based instrument to study solar and cosmic ray ions in lunar orbit or deep space. The objective of Solar Proton Anisotropy and Galactic cosmic ray High Energy Transport Instrument (SPAGHETI) is to provide multi-directional ion data to further understand anisotropies in SEP and GCR flux. The instrument is to be developed using large area detectors fabricated from high density, high purity silicon carbide (SiC) to measure linear energy transfer (LET) of ions. Stacks of these LET detectors are arranged in a CubeSat at orthogonal directions to provide multidirectional measurements. The low-noise, thermally-stable nature of silicon carbide and its radiation tolerance allows the multidirectional array of detector stacks to be packed in a 6U CubeSat without active cooling. A concept involving additional coincidence/anticoincidence detectors and a high energy Cherenkov detector is possible to further expand ion energy range and sensitivity.

  17. Implications of the differences between daytime and nighttime CloudSat observations over the tropics

    NASA Astrophysics Data System (ADS)

    Liu, Chuntao; Zipser, Edward J.; Mace, Gerald G.; Benson, Sally

    2008-04-01

    Using 1 year of CloudSat level 2B Cloud Geometrical Profile product, the vertical structures, geographical distributions, and seasonal variations of cloud occurrence at the daytime (1330 LT) and the nighttime (0130 LT) overpasses and their differences over tropical land and ocean are presented separately. The differences between the cloud and precipitation occurrence at 0130 and 1330 LT and the 24 h mean are quantitatively evaluated using climatologies of diurnal variation from 9 years of TRMM observations. Then the vertical structures, geographical distributions, and seasonal variations of cloud and precipitation near the two CloudSat overpass times are generated from 9 years of TRMM observations and compared to those from CloudSat. Larger differences between cloud and precipitation occurrences at 0130 LT and those at 1330 LT were found at high altitudes because the amplitude of diurnal variation increases with height. Cloud and precipitation occurrences show day versus night differences which are opposite with respect to each other in the upper troposphere over the tropics. For example, near 1330 LT over tropical oceans, there are more clouds, but less precipitation at 13-14 km than near 0130 LT except over Panama. This may be explained with the phase lags between precipitation and clouds in the life cycles of the convective systems over land and ocean. The differences between the seasonal cycles of cloud and precipitation sampled at the 0130 and 1330 LT A-Train overpass times and the seasonal cycles generated from full day samples are shown.

  18. The NSF CubeSat Program: The Promise of Scientific Projects (Invited)

    NASA Astrophysics Data System (ADS)

    Moretto, T.

    2009-12-01

    Working in the cubesat regime of space missions imposes obvious limitations on the complexity and scope of experiments that can be accomplished. However, these very small satellite projects also offer substantial advantages. In comparison to the traditional large satellite missions they provide a means to fast, near immediate, implementation of scientific ideas; to narrowly focused science investigations; to extended multi-point measurements; and to try out creative new, but high-risk, experimental approaches. Relatively simple but well-chosen measurements from CubeSat missions can complement observations from ground or large spacecraft missions to observe phenomena of interest over different geographic locations, at higher or lower altitudes, an at different local times. They can also provide crucial information on the small-scale structure of phenomena or help provide a global view. The powerful utility of all of these features is verified in the rich collection of scientific ideas emerging in response to the newly established NSF CubeSat program. The assortment of scientific investigations being proposed spans all across solar, magnetospheric, ionospheric, upper-atmospheric, and space weather research. Based on examples from current projects and potential future directions for the NSF CubeSat program, the presentation will explore the prolific scientific promise of the program.

  19. Feasibility for Orbital Life Extension of a CubeSat in the Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Blandino, John J.; Martinez-Baquero, Nicolas; Demetriou, Michael A.; Gatsonis, Nikolaos A.; Paschalidis, Nicholas

    2016-01-01

    Orbital flight of CubeSats at altitudes between 150 and 250 km has the potential to enable a new class of scientific, commercial, and defense-related missions. A study is presented to demonstrate the feasibility of extending the orbital lifetime of a CubeSat in a 210 km orbit. Propulsion consists of an electrospray thruster operating at a 2 W, 0.175 mN thrust, and an specific impulse (Isp) of 500 s. The mission consists of two phases. In phase 1, the CubeSat is deployed from a 414 km orbit and uses the thruster to deorbit to the target altitude of 210 km. In phase 2, the propulsion system is used to extend the mission lifetime until propellant is fully expended. A control algorithm based on maintaining a target orbital energy is presented that uses an extended Kalman filter to generate estimates of the orbital dynamic state, which are periodically updated by Global Positioning System measurements. For phase 1, the spacecraft requires 25.21 days to descend from 414 to 210 km, corresponding to a delta V = 96.25 m/s and a propellant consumption of 77.8 g. Phase 2 lasts 57.83 days, corresponding to a delta V = 119.15 m/s, during which the remaining 94.2 g of propellant are consumed.

  20. Development of a pointing, acquisition, and tracking system for a CubeSat optical communication module

    NASA Astrophysics Data System (ADS)

    Nguyen, Tam; Riesing, Kathleen; Kingsbury, Ryan; Cahoy, Kerri

    2015-03-01

    Miniaturized satellites such as CubeSats continue to improve their capabilities to enable missions that can produce significant amounts of data. For most CubeSat missions, data must be downlinked during short low-earth orbit ground station passes, a task currently performed using traditional radio systems. Free-space optical communications take advantage of the high gain of a narrow optical beam to achieve better link efficiency, allowing more valuable data to be downlinked over the mission lifetime. We present the Nanosatellite Optical Downlink Experiment (NODE) design, capable of providing a typical 3U (30 x 10 x 10 cm) CubeSat with a comparatively high data-rate downlink. The NODE optical communication module is designed to fit within a 5 x 10 x 10 cm volume, weigh less than 1 kg, and consume no more than 10Wof power during active communication periods. Our design incorporates a fine-steering mechanism and beacon-tracking system to achieve a 10 Mbps link rate. We describe the system-level requirements and designs for key components, including a transmitter, a beacon tracking camera, and a fast-steering mirror. We present simulation results of the uplink beacon tracking and fine steering of the downlink beam, including the effects of atmospheric fading and on-orbit environmental disturbances to demonstrate the feasibility of this approach.

  1. On-Orbit Results From the TacSat-2 ACTD Target Indicator Experiment AIS Payload

    NASA Astrophysics Data System (ADS)

    Duffey, T.; Huffine, C.; Nicholson, S.

    2008-08-01

    As part of the US Department of Defense's Operationally Responsive Space (ORS) initiative, the Naval Research Laboratory (NRL) developed the Target Indicator Experiment (TIE) payload for the TacSat-2 spacecraft, which was launched 16 December, 2006 on a Minotaur 1 launch vehicle from Wallops Island, Virginia. The TIE payload was an improved version of the primary payload developed for the TacSat-1 spacecraft. One of the main enhancements was the addition of a software definable radio receiver and demodulator for the collection of the Automated Identification System (AIS) signal now required globally on large ships for maritime safety and security. While several systems have been proposed, TacSat-2 was the first small satellite to successfully collect AIS signals from space. This paper presents an overview of the design of the TIE payload AIS system, the collection experiments that were performed during the life of the spacecraft, the results of those experiments, samples of the data collected, and recommendations for future systems.

  2. Signal Amplification Technique (SAT): an approach for improving resolution and reducing image noise in computed tomography

    SciTech Connect

    Phelps, M.E.; Huang, S.C.; Hoffman, E.J.; Plummer, D.; Carson, R.

    1981-01-01

    Spatial resolution improvements in computed tomography (CT) have been limited by the large and unique error propagation properties of this technique. The desire to provide maximum image resolution has resulted in the use of reconstruction filter functions designed to produce tomographic images with resolution as close as possible to the intrinsic detector resolution. Thus, many CT systems produce images with excessive noise with the system resolution determined by the detector resolution rather than the reconstruction algorithm. CT is a rigorous mathematical technique which applies an increasing amplification to increasing spatial frequencies in the measured data. This mathematical approach to spatial frequency amplification cannot distinguish between signal and noise and therefore both are amplified equally. We report here a method in which tomographic resolution is improved by using very small detectors to selectively amplify the signal and not noise. Thus, this approach is referred to as the signal amplification technique (SAT). SAT can provide dramatic improvements in image resolution without increases in statistical noise or dose because increases in the cutoff frequency of the reconstruction algorithm are not required to improve image resolution. Alternatively, in cases where image counts are low, such as in rapid dynamic or receptor studies, statistical noise can be reduced by lowering the cutoff frequency while still maintaining the best possible image resolution. A possible system design for a positron CT system with SAT is described.

  3. Smartphone qualification & linux-based tools for CubeSat computing payloads

    NASA Astrophysics Data System (ADS)

    Bridges, C. P.; Yeomans, B.; Iacopino, C.; Frame, T. E.; Schofield, A.; Kenyon, S.; Sweeting, M. N.

    Modern computers are now far in advance of satellite systems and leveraging of these technologies for space applications could lead to cheaper and more capable spacecraft. Together with NASA AMES's PhoneSat, the STRaND-1 nanosatellite team has been developing and designing new ways to include smart-phone technologies to the popular CubeSat platform whilst mitigating numerous risks. Surrey Space Centre (SSC) and Surrey Satellite Technology Ltd. (SSTL) have led in qualifying state-of-the-art COTS technologies and capabilities - contributing to numerous low-cost satellite missions. The focus of this paper is to answer if 1) modern smart-phone software is compatible for fast and low-cost development as required by CubeSats, and 2) if the components utilised are robust to the space environment. The STRaND-1 smart-phone payload software explored in this paper is united using various open-source Linux tools and generic interfaces found in terrestrial systems. A major result from our developments is that many existing software and hardware processes are more than sufficient to provide autonomous and operational payload object-to-object and file-based management solutions. The paper will provide methodologies on the software chains and tools used for the STRaND-1 smartphone computing platform, the hardware built with space qualification results (thermal, thermal vacuum, and TID radiation), and how they can be implemented in future missions.

  4. DebriSat- A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterization

    NASA Astrophysics Data System (ADS)

    Liou, J.-C.; Clark, S.; Fitz-Coy, N.; Huynh, T.; Opiela, J.; Polk, M.; Roebuck, B.; Rushing, R.; Sorge, M.; Werremeyer, M.

    2013-08-01

    The goal of the DebriSat project is to characterize fragments generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960s U.S. Navy Transit satellite. There are three phases to this project: the design and fabrication of DebriSat - an engineering model representing a modern, 60-cm/50-kg LEO satellite; performance of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area-to-mass ratio, density, shape, material composition, optical properties, and radar cross-section distributions, will be used to supplement the DoD and NASA satellite breakup models to better describe the breakup outcome of a modern satellite.

  5. Structural Qualification Testing of the WindSat Payload Using Sine Bursts Near Structural Resonance

    NASA Technical Reports Server (NTRS)

    Pontius, Jim; Barnes, Donald; Broduer, Steve (Technical Monitor)

    2001-01-01

    Sine burst tests are often used for structural qualification of space flight hardware. In most instances, the driving frequency of the shaker is specified far below the structure's first resonant mode, such that the entire test article sees uniform acceleration. For large structures, this limits qualification testing to lower parts of the structure, or else it over-tests the lower structure to achieve qualification of the upper structure. The WindSat payload, a 10.5 foot tall graphite/epoxy, titanium, and aluminum radiometer, experiences accelerations at the six foot diameter reflector nearly four times that at the spacecraft interface. Due to size of the payload, the number of bonded joints, and the lightweight reflector support structure design and construction, using static pull testing to qualify all of the bonded joints in the upper structure would result in large, expensive, and extensive test fixturing. Sine burst testing near the first two structural resonant modes was performed on the WindSat payload to achieve the correct load factor distribution up the stack for structural qualification. In this presentation, how finite element method (FEM) sine burst predictions were used in conjunction with low level random and sine burst tests to achieve correct qualification test load factor distribution on the WindSat payload is discussed. Also presented is the risk mitigation approach for using the uncorrelated FEM in this procedure.

  6. Science Results and Lessons Learned from CubeSat: Colorado Space Weather Experiment (CSSWE)

    NASA Astrophysics Data System (ADS)

    Li, Xinlin

    The Relativistic Electron and Proton Telescope integrated little experiment (REPTile) is a loaded-disc collimated solid-state particle telescope, designed, built, tested, and operated by a team of students at the University of Colorado. It is the only science payload onboard the Colorado Student Space Weather Experiment (CSSWE), a 3U CubeSat (10cm x 10cm x 30cm) launched into a low-Earth, 480km x 780km, and highly inclined (65 deg) orbit on 13 September 2012. REPTile measures differential fluxes of 0.58 to >3.8 MeV electrons and 9-40 MeV protons. These measurements, by themselves and in conjunction with other larger missions, are critical to understand the dynamics of these energetic particles. Miniaturizing a power- and mass-hungry particle telescope to return clean measurements from a CubeSat platform is challenging. To overcome these challenges, REPTile underwent a rigorous design and testing phase. Despite the limitations inherent with CubeSats, REPTile to date (still in operation) has returned more than 300 days of valuable science data, more than tripling its nominal mission lifetime of 90 days. The data are clean, as REPTile is able to clearly distinguish between particle species. Important science results using REPTile data, some of which have been published in peer-reviewed journals, will be presented in this presentation.

  7. Downregulation of de Novo Fatty Acid Synthesis in Subcutaneous Adipose Tissue of Moderately Obese Women.

    PubMed

    Guiu-Jurado, Esther; Auguet, Teresa; Berlanga, Alba; Aragonès, Gemma; Aguilar, Carmen; Sabench, Fàtima; Armengol, Sandra; Porras, José Antonio; Martí, Andreu; Jorba, Rosa; Hernández, Mercè; del Castillo, Daniel; Richart, Cristóbal

    2015-12-16

    The purpose of this work was to evaluate the expression of fatty acid metabolism-related genes in human adipose tissue from moderately obese women. We used qRT-PCR and Western Blot to analyze visceral (VAT) and subcutaneous (SAT) adipose tissue mRNA expression involved in de novo fatty acid synthesis (ACC1, FAS), fatty acid oxidation (PPARα, PPARδ) and inflammation (IL6, TNFα), in normal weight control women (BMI < 25 kg/m², n = 35) and moderately obese women (BMI 30-38 kg/m², n = 55). In SAT, ACC1, FAS and PPARα mRNA expression were significantly decreased in moderately obese women compared to controls. The downregulation reported in SAT was more pronounced when BMI increased. In VAT, lipogenic-related genes and PPARα were similar in both groups. Only PPARδ gene expression was significantly increased in moderately obese women. As far as inflammation is concerned, TNFα and IL6 were significantly increased in moderate obesity in both tissues. Our results indicate that there is a progressive downregulation in lipogenesis in SAT as BMI increases, which suggests that SAT decreases the synthesis of fatty acid de novo during the development of obesity, whereas in VAT lipogenesis remains active regardless of the degree of obesity.

  8. Molecular characterization of SAT-2 foot-and-mouth disease virus isolates obtained from cattle during a four-month period in 2001 in Limpopo Province, South Africa.

    PubMed

    Phologane, B S; Dwarka, R M; Haydon, D T; Gerber, L J; Vosloo, W

    2008-12-01

    Foot-and-mouth disease (FMD) is an acute, highly contagious viral infection of domestic and wild cloven-hoofed animals. The virus is a single-stranded RNA virus that has a high rate of nucleotide mutation and amino acid substitution. In southern Africa the South African Territories (SAT) 1-3 serotypes of FMD virus are maintained by large numbers of African buffaloes (Syncerus caffer), which provide a potential source of infection for domestic livestock and wild animals. During February 2001, an outbreak of SAT-2 was recorded in cattle in the FMD control zone of South Africa, adjacent to the Kruger National Park (KNP). They had not been vaccinated against the disease since they form the buffer between the vaccination and free zones but in the face of the outbreak, they were vaccinated as part of the control measures to contain the disease. The virus was, however, isolated from some of them on several occasions up to May 2001. These isolates were characterized to determine the rate of genetic change in the main antigenic determinant, the 1 D/2A gene. Nucleotide substitutions at 12 different sites were identified of which five led to amino acid changes. Three of these occurred in known antigenic sites, viz. the GH-loop and C-terminal part of the protein, and two of these have previously been shown to be subject to positive selection. Likelihood models indicated that the ratio of non-synonymous to synonymous changes among the outbreak sequences recovered from cattle was four times higher than among comparable sequences isolated from wildlife, suggesting that the virus may be under greater selective pressure during rapid transmission events.

  9. A Review Of CryoSat-2/SIRAL Applications For The Monitoring Of River Water Levels

    NASA Astrophysics Data System (ADS)

    Bercher, Nicolas; Dinardo, Salvatore; Lucas, Bruno Manuel; Fleury, Sara; Calmant, Stephane; Femenias, Pierre; Boy, Francois; Picot, Nicolas; Benveniste, Jerome

    2013-12-01

    Regarding hydrology applications and particularly the monitoring of river water levels from space, the CryoSat- 2 ice mission has two main valuable characteristics: (1) its geodetic orbit and (2) the altimeter's SAR and SARin modes. The benefits of the geodetic orbit of the satellite have been illustrated in the frame of the ”20 years of progress in radar altimetry” symposium (Venice, 2012) [2]. It has been shown that, with such an orbit, the way river water level was monitored using conventional altimeters had to be revisited. In particular, using LRM mode only, CryoSat-2 allowed us to build spatio-temporal time series of the river water level, to map river's topography and eventually derive pseudo-time series and pseudo-profiles of the river. This paper focuses on the new ways to use altimetry for the monitoring of river water levels. SIRAL's (CryoSat-2 altimeter) SAR and SARin modes have the ability to deliver surface heights with an unprecedented along-track resolution of about 300 m. Moreover, using the SARin mode (involving the satellite's two antennas), the cross- track angle of the retracked echo is also available in routine. These two aspects of the SARin mode (high resolution and cross-track angle) make it a new tool to distinguish whether the retracked echo came from the sur- face of interest (e.g., a river) or any other reflective object nearby the surface of interest (e.g., another river section, lakes or temporary lake after flooding events or any other specular surfaces). We introduce the multiple benefits of using the intermediate multi-look matrix (also known as stack matrix), among them: (1) to refine and select among the multiple Doppler-beam waveforms before averaging and retracking them, and (2) to be able to study the surfaces response according to their view angle. Custom products processed at ESA (ESRIN) by Dinardo et al. [7], in the perspective of Sentinel-3, as well as official CryoSat-2 L1b and L2 products were used to illustrate

  10. Estimation of Arctic Sea Ice Freeboard and Thickness Using CryoSat-2

    NASA Astrophysics Data System (ADS)

    Lee, Sanggyun; Im, Jungho; yoon, Hyeonjin; Shin, Minso; Kim, Miae

    2014-05-01

    Arctic sea ice is one of the significant components of the global climate system as it plays a significant role in driving global ocean circulation, provides a continuous insulating layer at air-sea interface, and reflects a large portion of the incoming solar radiation in Polar Regions. Sea ice extent has constantly declined since 1980s. Its area was the lowest ever recorded on 16 September 2012 since the satellite record began in 1979. Arctic sea ice thickness has also been diminishing along with the decreasing sea ice extent. Because extent and thickness, two main characteristics of sea ice, are important indicators of the polar response to on-going climate change, there has been a great effort to quantify them using various approaches. Sea ice thickness has been measured with numerous field techniques such as surface drilling and deploying buoys. These techniques provide sparse and discontinuous data in spatiotemporal domain. Spaceborne radar and laser altimeters can overcome these limitations and have been used to estimate sea ice thickness. Ice Cloud and land Elevation Satellite (ICEsat), a laser altimeter from National Aeronautics and Space Administration (NASA), provided data to detect polar area elevation change between 2003 and 2009. CryoSat-2 launched with Synthetic Aperture Radar (SAR)/Interferometric Radar Altimeter (SIRAL) on April 2010 can provide data to estimate time-series of Arctic sea ice thickness. In this study, Arctic sea ice freeboard and thickness in 2012 and 2013 were estimated using CryoSat-2 SAR mode data that has sea ice surface height relative to the reference ellipsoid WGS84. In order to estimate sea ice thickness, freeboard height, elevation difference between the top of sea ice surface and leads should be calculated. CryoSat-2 profiles such as pulse peakiness, backscatter sigma-0, number of echoes, and significant wave height were examined to distinguish leads from sea ice. Several near-real time cloud-free MODIS images as CryoSat-2

  11. The CryoSat Interferometer after 6 years in orbit: calibration and achievable performance

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; De Bartolomei, Maurizio; Bouffard, Jerome; Parrinello, Tommaso

    2016-04-01

    The main payload of CryoSat is a Ku-band pulse width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. In fact, the across-track echo direction can be derived by exploiting the precise knowledge of the baseline vector (i.e. the vector between the two antennas centers of phase) and simple geometry. The end-to-end calibration strategy for the CryoSat interferometer consists on in-orbit calibration campaigns following the approach described in [1]. From the beginning of the CryoSat mission, about once a year the interferometer calibration campaigns have been periodically performed by rolling left and right the spacecraft of about ±0.4 deg. This abstract is aimed at presenting our analysis of the calibration parameters and of the achievable performance of the CryoSat interferometer over the 6 years of mission. Additionally, some further studies have been performed to assess the accuracy of the roll angle computed on ground as function of the aberration (the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the object) correction applied to the attitude quaternions, provided by the Star Tracker mounted on-board. In fact, being the roll information crucial to obtain an accurate estimate of the angle of arrival, the data from interferometer calibration campaigns have been used to verify how the application of the aberration correction affects the roll information and, in turns, the measured angle of arrival. [1] Galin, N.; Wingham, D.J.; Cullen, R.; Fornari, M.; Smith, W.H.F.; Abdalla, S., "Calibration of the CryoSat-2 Interferometer and Measurement of Across

  12. Electro-Optical Payloads and CubeSat Missions for Earth and Space Science

    NASA Astrophysics Data System (ADS)

    Swenson, C.; Marchant, A.

    2015-12-01

    Small, low-power electro-optical scientific payloads are required if small satellites and CubeSats are to become significant enablers of new science. Although these are just one class of scientific instrumentation they have often played a key role in many scientific discoveries. The most significant advances in Earth and space science, over the next decade are most likely to derive from new observational techniques. The connection between advances in scientific understanding and technology has historically been demonstrated across many disciplines and time. In this paper we present a review of three such sensors and the associated CubeSat missions and scientific investigation enabled. Each mission involves a relatively recently developed small electro-optical sensor which is tightly integrated with the small satellite bus in to a "Science Craft". The first is the NSF funded OPAL mission which makes use of a high-sensitivity, hyper-spectral limb imager to observe the daytime O2 A-band (near 762nm) emission. These observations allow the temperature of the lower thermosphere to be determined and address questions on the energy budget and response of the thermosphere to geomagnetic storms. The second is the MeNISCuS mission Methane Nadir Imaging Spatial-heterodyne CubeSat Spectrometer which is a demonstration of the volume holographic grating (VHG) spatial heterodyne spectrometer developed under a NASA-sponsored STTR contract. Methane (CH4) is the second most important greenhouse gas and although burning methane produces less CO2 than oil or coal, methane's global warming potential is about ~30 times higher. As a result, if methane leak rates are greater than 3-5%, the warming potential will outweigh the benefit of reduced CO2. The sources of such leaks can be discovered using missions like MeNISCuS. The third instrument and mission is SEDI a CubeSat scaled Fabry-Perot spectrometer focused on a narrow band around the OI(630) red line for observing winds in the

  13. CryoSat-2: Measuring fluctuations of land and marine ice fields from space

    NASA Astrophysics Data System (ADS)

    Francis, Richard; Wingham, Duncan; Cullen, Robert

    2010-05-01

    1. INTRODUCTION CryoSat was chosen as the first of ESA's Earth Explorer Opportunity missions in late 1999, following a competitive selection process [1]. Unfortunately, the CryoSat satellite was lost as the result of a launch failure on 8 October 2005. The decision was made to rebuild the satellite in order to complete the mission, and as a result of this the new satellite, CryoSat-2, will be launched on 25 February 2010. 2. MISSION OBJECTIVES The mission goal of CryoSat is the measurement of secular change in the cryosphere, particularly in the elevation of the ice caps and the thickness of sea ice [2]. The required accuracy corresponds to about half of the variation expected due to natural variability, over reasonable scales for the surfaces concerned. The selected technique is radar altimetry, although the instrument has been modified to provide the enhanced capabilities needed to significantly extend the spatial coverage of previous altimetry missions, particularly ERS and EnviSat. Thus the radar includes a synthetic aperture mode which enables the along- track resolution to be improved to about 250 m. This will enable detection of leads in sea-ice which are narrower than those detected hitherto, so that operation deeper into pack-ice can be achieved with a consequent reduction in errors due to omission. Altimetry over the steep edges of ice caps is hampered by the irregular topography which, since the radar ranging is performed to the closest reflector rather than the point directly below, introduces uncertainty into the exactitude of repeat measurements. CryoSat's radar includes a second antenna and receiver chain so that interferometry may be used to determine the arrival angle of the echo and so improve localisation of the reflection. The satellite payload, which includes a DORIS receiver for precise orbit determination and a set of star trackers to measure the orientation of the interferometer, is quite complex and demanding. 3. CRYOSAT-1 LAUNCH FAILURE

  14. Global Tropical Cyclone Winds from the QuikSCAT and OceanSAT-2 Scatterometers

    NASA Astrophysics Data System (ADS)

    Stiles, B. W.; Danielson, R. E.; Poulsen, W. L.; Fore, A.; Brennan, M. J.; Shen, T. J.; Hristova-Veleva, S. M.

    2012-12-01

    We have produced a comprehensive set of tropical cyclone storm wind retrieval scenes for all ten years of QuikSCAT data and one year of OceanSAT-2 data. The wind speeds were corrected for rain and optimized to avoid saturation at high winds using an artificial neural network method similar to that in [1] and [2]. The QuikSCAT wind imagery and the quantitative speed, direction, and backscatter data can be obtained at http://tropicalcyclone.jpl.nasa.gov. The QuikSCAT wind speeds have been validated against best track intensity (i.e., maximum wind speeds), H*WIND tropical cyclone wind model analysis fields, and wind speeds from aircraft overflights (GPS drop wind sondes and step frequency microwave radiometer (SFMR) wind measurements). Storms from all basins are included for a total of 21600 scenes over the ten years of nominal QuikSCAT operations. Of these, 11435 scenes include the best track center of the cyclone in the retrieved wind field. Among these, 3295 were of tropical storms and 788, 367, 330, 289, and 55 were of category 1, 2, 3, 4 and 5 hurricanes, respectively, on the Saffir-Simpson Hurricane Wind Scale. In addition to the QuikSCAT hurricane winds, we have also processed one year of wind fields from the Indian Space Research organization (ISRO) OceanSAT-2 satellite. OceanSAT-2 employs a scanning pencil beam Ku-band scatterometer with a design similar to QuikSCAT. JPL and NOAA have been working extensively with ISRO to aid in cross calibration between OceanSAT-2 and QuikSCAT. Toward this end the QuikSCAT instrument has been repointed in order to acquire data at the OceanSAT-2 incidence angles, and several meetings in India between the teams have taken place. The neural network that was trained on QuikSCAT data was used to retrieve OceanSAT-2 winds. The backscatter inputs to the network were transformed to match the histograms of the corresponding values in the QuikSCAT data set. We examine the scatterometer winds to investigate the relationship between

  15. Combining Envisat type and CryoSat-2 altimetry to inform hydrodynamic models

    NASA Astrophysics Data System (ADS)

    Schneider, Raphael; Nygaard Godiksen, Peter; Villadsen, Heidi; Madsen, Henrik; Bauer-Gottwein, Peter

    2015-04-01

    Hydrological models are developed and used for flood forecasting and water resources management. Such models rely on a variety of input and calibration data. In general, and especially in data scarce areas, remote sensing provides valuable data for the parameterization and updating of such models. Satellite radar altimeters provide water level measurements of inland water bodies. So far, many studies making use of satellite altimeters have been based on data from repeat-orbit missions such as Envisat, ERS or Jason or on synthetic wide-swath altimetry data as expected from the SWOT mission. This work represents one of the first hydrologic applications of altimetry data from a drifting orbit satellite mission, using data from CryoSat-2. We present an application where CryoSat-2 data is used to improve a hydrodynamic model of the Ganges and Brahmaputra river basins in South Asia set up in the DHI MIKE 11 software. The model's parameterization and forcing is mainly based on remote sensing data, for example the TRMM 3B42 precipitation product and the SRTM DEM for river and subcatchment delineation. CryoSat-2 water levels were extracted over a river mask derived from Landsat 7 and 8 imagery. After calibrating the hydrological-hydrodynamic model against observed discharge, simulated water levels were fitted to the CryoSat-2 data, with a focus on the Brahmaputra river in the Assam valley: The average simulated water level in the hydrodynamic model was fitted to the average water level along the river's course as observed by CryoSat-2 over the years 2011-2013 by adjusting the river bed elevation. In a second step, the cross section shapes were adjusted so that the simulated water level dynamics matched those obtained from Envisat virtual station time series. The discharge calibration resulted in Nash-Sutcliffe coefficients of 0.86 and 0.94 for the Ganges and Brahmaputra. Using the Landsat river mask, the CryoSat-2 water levels show consistency along the river and are in

  16. Crystal structure of bis-(tri-ethano-lamine-κ(3) N,O,O')nickel(II) bis-(3-hy-droxy-benzoate) tetra-hydrate.

    PubMed

    Ibragimov, Aziz B

    2016-05-01

    The reaction of 3-hy-droxy-benzoic (m-hy-droxy-benzoic) acid (MHBA), tri-ethano-lamine (TEA) and Ni(NO3)2 in aqueous solution led to formation of the hydrated title salt, [Ni(C6H15NO3)2](C7H5O3)·4H2O. In the complex cation, the Ni(2+) ion is located on an inversion centre. Two symmetry-related TEA ligands occupy all coordination sites in an N,O,O'-tridentate coordination, leading to a slightly distorted NiN2O4 octa-hedron. Two ethanol groups of each TEA ligand form two five-membered chelate rings around Ni(2+), while the third ethanol group does not coordinate to the metal atom. Two MHBA(-) anions in the benzoate form are situated in the outer coordination sphere for charge compensation. An intricate network of hydrogen bonds between the free and coordinating hy-droxy groups of the TEA ligands, the O atoms of the MHBA(-) anions and the water mol-ecules leads to the formation of a two-dimensional structure extending parallel to (010).

  17. Can rare SAT formulae be easily recognized? On the efficiency of message-passing algorithms for K-SAT at large clause-to-variable ratios

    NASA Astrophysics Data System (ADS)

    Altarelli, Fabrizio; Monasson, Rémi; Zamponi, Francesco

    2007-02-01

    For large clause-to-variable ratios, typical K-SAT instances drawn from the uniform distribution have no solution. We argue, based on statistical mechanics calculations using the replica and cavity methods, that rare satisfiable instances from the uniform distribution are very similar to typical instances drawn from the so-called planted distribution, where instances are chosen uniformly between the ones that admit a given solution. It then follows, from a recent article by Feige, Mossel and Vilenchik (2006 Complete convergence of message passing algorithms for some satisfiability problems Proc. Random 2006 pp 339-50), that these rare instances can be easily recognized (in O(log N) time and with probability close to 1) by a simple message-passing algorithm.

  18. Effects of fatty acid supplements on milk yield and energy balance of lactating dairy cows.

    PubMed

    Harvatine, K J; Allen, M S

    2006-03-01

    Saturated and unsaturated fatty acid supplements (FS) were evaluated for effects on yield of milk and milk components, concentration of milk components including milk fatty acid profile, and energy balance. Eight ruminally and duodenally cannulated cows and 8 noncannulated cows were used in a replicated 4 x 4 Latin square design experiment with 21-d periods. Treatments were control and a linear substitution of 2.5% fatty acids from saturated FS (SAT; prilled, hydrogenated free fatty acids) for partially unsaturated FS (UNS; calcium soaps of long-chain fatty acids). The SAT treatment did not change milk fat concentration, but UNS linearly decreased milk fat in cannulated cows and tended to decrease milk fat in noncannulated cows compared with control. Milk fat depression with UNS corresponded to increased concentrations of trans-10, cis-12 conjugated linoleic acid and trans C18:1 fatty acids in milk. Milk fat profile was similar for SAT and control, but UNS decreased concentration of short- and medium-chain FA. Digestible energy intake tended to decrease linearly with increasing unsaturated FS in cannulated and noncannulated cows. Increasing unsaturated FS linearly increased empty body weight and net energy gain in cannulated cows, whereas increasing saturated FS linearly increased plasma insulin. Efficiency of conversion of digestible energy to milk tended to decrease linearly with increasing unsaturated FS for cannulated cows only. Addition of SAT provided little benefit to production and energy balance, whereas UNS decreased energy intake and milk energy yield.

  19. A Toolkit For CryoSat Investigations By The ESRIN EOP-SER Altimetry Team

    NASA Astrophysics Data System (ADS)

    Dinardo, Salvatore; Bruno, Lucas; Benveniste, Jerome

    2013-12-01

    The scope of this work is to feature the new tool for the exploitation of the CryoSat data, designed and developed entirely by the Altimetry Team at ESRIN EOP-SER (Earth Observation - Exploitation, Research and Development). The tool framework is composed of two separate components: the first one handles the data collection and management, the second one is the processing toolkit. The CryoSat FBR (Full Bit Rate) data is downlinked uncompressed from the satellite, containing un-averaged individual echoes. This data is made available in the Kiruna CalVal server in a 10 day rolling archive. Daily at ESRIN all the CryoSat FBR data, in SAR and SARin Mode, are downloaded (around 30 Gigabytes) catalogued and archived in local ESRIN EOP-SER workstations. As of March 2013, the total amount of FBR data is over 9 Terabytes, with CryoSat acquisition dates spanning January 2011 to February 2013 (with some gaps). This archive was built by merging partial datasets available at ESTEC and NOAA, that have been kindly made available for EOP-SER team. The on-demand access to this low level data is restricted to expert users with validated ESA P.I. credentials. Currently the main users of the archiving functionality are the team members of the Project CP4O (STSE- CryoSat Plus for Ocean), CNES and NOAA. The second component of the service is the processing toolkit. On the EOP-SER workstations there is internally and independently developed software that is able to process the FBR data in SAR/SARin mode to generate multi-looked echoes (Level 1B) and subsequently able to re-track them in SAR and SARin mode (Level 2) over open ocean, exploiting the SAMOSA model and other internally developed models. The processing segment is used for research & development scopes, supporting the development contracts awarded confronting the deliverables to ESA, on site demonstrations/training to selected users, cross- comparison against third part products (CLS/CNES CPP Products for instance), preparation

  20. The Measurement of Landfill Gas Emissions with the Orbiting Carbon Observatory and CarbonSAT Satellites

    NASA Astrophysics Data System (ADS)

    Vigil, S. A.; Bovensmann, H.

    2010-12-01

    Landfill gas is a significant contributor to anthropogenic emissions of CH4 and CO2. The U.S. Environmental Protection Agency has estimated the total U.S. 2007 emissions of the CH4 component of landfill gas at 132.9 Tg CO2 Equivalent. This compares to total CH4 emission from all US sources in 2007 at 585.3 Tg CO2 Equivalent. Worldwide CH4 emissions from landfill gas have been estimated at 668 Tg CO2 Equivalent. Satellite remote sensing can also be used to characterize landfill gas emissions. The NASA Orbiting Carbon Observatory (OCO-2) and the proposed CarbonSAT (University of Bremen) satellites are particularly suited for this purpose. The Orbiting Carbon Observatory (OCO) was designed to provided high spatial resolution ( < 3 km2 footprints) and high accuracy ( 0.5 to 3 ppm) CO2 measurements. The original OCO satellite failed to achieve orbit in February 2009. A replacement satellite (OCO-2) is under construction and scheduled for launch in February 2013. These characteristics will allow the measurement of CO2 emissions from large landfills on the orbit path. Because surface landfill gas emissions include both CH4 and CO2 , the CH4 concentration can be inferred from CO2 concentrations. The CarbonSAT satellite which is being designed by the University of Bremen, Institute for Environmental Physics, has similar characteristics to OCO-2 but it has been optimized for measurement of both CH4 and CO2 . Key specifications for the CarbonSAT satellite include XCO2 single measurement error of < 1 to 3 ppm and XCH4 single measurement error of < 10 to 18 ppb. These characteristics will make it possible to detect both CO2 and CH4 emissions from large landfills. The spatial resolution and accuracy of the CO2 measurements from OCO-2 and CO2 and CH4 measurements from CarbonSAT present a unique opportunity to measure landfill gas emissions from large landfills such as exist in the United States and other developed countries. In general, landfills in the developed countries have

  1. CLIpSAT for Interplanetary Missions: Common Low-cost Interplanetary Spacecraft with Autonomy Technologies

    NASA Astrophysics Data System (ADS)

    Grasso, C.

    2015-10-01

    Blue Sun Enterprises, Inc. is creating a common deep space bus capable of a wide variety of Mars, asteroid, and comet science missions, observational missions in and near GEO, and interplanetary delivery missions. The spacecraft are modular and highly autonomous, featuring a common core and optional expansion for variable-sized science or commercial payloads. Initial spacecraft designs are targeted for Mars atmospheric science, a Phobos sample return mission, geosynchronous reconnaissance, and en-masse delivery of payloads using packetized propulsion modules. By combining design, build, and operations processes for these missions, the cost and effort for creating the bus is shared across a variety of initial missions, reducing overall costs. A CLIpSAT can be delivered to different orbits and still be able to reach interplanetary targets like Mars due to up to 14.5 km/sec of delta-V provided by its high-ISP Xenon ion thruster(s). A 6U version of the spacecraft form fits PPOD-standard deployment systems, with up to 9 km/s of delta-V. A larger 12-U (with the addition of an expansion module) enables higher overall delta-V, and has the ability to jettison the expansion module and return to the Earth-Moon system from Mars orbit with the main spacecraft. CLIpSAT utilizes radiation-hardened electronics and RF equipment, 140+ We of power at earth (60 We at Mars), a compact navigation camera that doubles as a science imager, and communications of 2000 bps from Mars to the DSN via X-band. This bus could form the cornerstone of a large number asteroid survey projects, comet intercept missions, and planetary observation missions. The TugBot architecture uses groups of CLIpSATs attached to payloads lacking innate high-delta-V propulsion. The TugBots use coordinated trajectory following by each individual spacecraft to move the payload to the desired orbit - for example, a defense asset might be moved from GEO to lunar transfer orbit in order to protect and hide it, then returned

  2. ΔDsat, a QB50 CubeSat mission to study rarefied-gas drag modelling

    NASA Astrophysics Data System (ADS)

    Virgili, Josep; Roberts, Peter C. E.

    2013-08-01

    A CubeSat mission to study the impact of flow incidence angle, surface material and surface roughness on gas-surface interactions on spacecraft in low Earth orbits has been designed. To accomplish this scientific goal the CubeSat deploys a variable geometry aerofoil capable of exposing different surfaces to the flow at different incident angles. By using the on-board GPS measurements and an orbit determination technique the drag experienced by the CubeSat can be estimated. The CubeSat has been designed to be part of the QB50 mission, and hence it carries a sensor that can take in-situ measurements of the atmosphere. This is then used to estimate the atmospheric density and hence to extract information on the drag coefficient. To minimise any bias present in the measurement chain a differential approach is used. Therefore no absolute drag coefficients are estimated, instead, ratios of drag coefficients are computed. This allows direct comparisons of the drag coefficients of different materials, different surface roughness or different incident angles. Simulations indicate that this CubeSat mission will be able to obtain drag coefficient ratios with an uncertainty level of less than 5%.

  3. CryoSat-2 science algorithm status, expected future improvements and impacts concerning Sentinel-3 and Jason-CS missions

    NASA Astrophysics Data System (ADS)

    Cullen, R.; Wingham, D.; Francis, R.; Parrinello, T.

    2011-12-01

    With CryoSat-2 soon to enter its second year of post commissioning operations there is now sufficient experience and evidence showing improvements of the SIRAL's (Synthetic interferometric radar altimeter) SAR and SARIn modes over conventional pulse-width limited altimeters for both the targeted marine/land ice fields but also for non mission relevant surfaces such as the ocean, for example. In the process of understanding the CryoSat data some side effects of the end-to-end platform measurement and ground retrieval system have been identified and whilst those key to mission success are understood and are being handled others, remain open and pave the way to longer term fine-tuning. Of interest to the session will be a summary of the manditory changes made during 2011 to all the modes of CryoSat-2 science processing with a view to longer term algorithm improvements that could benefit the planned mid-to-late nominal operations re-processing. Since some of the science processor improvements have direct implication to the SAR mode processing of Sentinel-3 and Jason-CS science then these will also be highlighted. Finally a summary of the CryoSat-2 in-orbit platform and payload performances and their stability will also be provided. Expectations of the longer term uses of CryoSat's primary sensor (SIRAL) and its successors will be discussed.

  4. ESA Earth Explorer 8 Candidate Mission CarbonSat: Error Budget for Atmospheric Carbon Dioxide and Methane Retrievals

    NASA Astrophysics Data System (ADS)

    Buchwitz, M.; Bovensmann, H.; Reuter, M.; Krings, T.; Heymann, J.; Schneising, O.; Burrows, J. P.; Boesch, H.; Meijer, Y.; Sierk, B.; Loscher, A.; Caron, J.; Ingmann, P.

    2015-11-01

    CarbonSat is one of two candidate missions for ESA's Earth Explorer 8 (EE8) satellite; one of them will be selected for implementation in November 2015 for a targeted launch date around 2023. The main goal of CarbonSat is to advance our knowledge of the sources and sinks, both natural and man-made, of the two most important anthropogenic greenhouse gases; carbon dioxide (CO2) and methane (CH4) from the global via the sub-continental to the local scale. CarbonSat will be the first satellite mission to image local scale emission hot spots of CO2 (e.g., cities, volcanoes, industrial areas) and CH4 (e.g., fossil fuel production, landfills, seeps) and to quantify their emissions and discriminate them from surrounding biospheric fluxes. The primary geophysical data products of CarbonSat are atmospheric column- averaged dry air mole fractions of CO2 and CH4, i.e., XCO2 (in ppm) and XCH4 (in ppb), respectively. In addition, CarbonSat will deliver a number of secondary data products, which will also be of good quality, such as vegetation chlorophyll Sun-Induced Fluorescence (SIF) as retrieved from clear solar Fraunhofer lines located at 755 nm; SIF will be retrieved simultaneously with the primary products. Here we present an updated error budget using the latest retrieval algorithm and instrument/mission specification focusing on nadir observations over land.

  5. A scalable and accurate targeted gene assembly tool (SAT-Assembler) for next-generation sequencing data.

    PubMed

    Zhang, Yuan; Sun, Yanni; Cole, James R

    2014-08-01

    Gene assembly, which recovers gene segments from short reads, is an important step in functional analysis of next-generation sequencing data. Lacking quality reference genomes, de novo assembly is commonly used for RNA-Seq data of non-model organisms and metagenomic data. However, heterogeneous sequence coverage caused by heterogeneous expression or species abundance, similarity between isoforms or homologous genes, and large data size all pose challenges to de novo assembly. As a result, existing assembly tools tend to output fragmented contigs or chimeric contigs, or have high memory footprint. In this work, we introduce a targeted gene assembly program SAT-Assembler, which aims to recover gene families of particular interest to biologists. It addresses the above challenges by conducting family-specific homology search, homology-guided overlap graph construction, and careful graph traversal. It can be applied to both RNA-Seq and metagenomic data. Our experimental results on an Arabidopsis RNA-Seq data set and two metagenomic data sets show that SAT-Assembler has smaller memory usage, comparable or better gene coverage, and lower chimera rate for assembling a set of genes from one or multiple pathways compared with other assembly tools. Moreover, the family-specific design and rapid homology search allow SAT-Assembler to be naturally compatible with parallel computing platforms. The source code of SAT-Assembler is available at https://sourceforge.net/projects/sat-assembler/. The data sets and experimental settings can be found in supplementary material.

  6. Preliminary Analysis of Delta-V Requirements for a Lunar CubeSat Impactor with Deployment Altitude Variations

    NASA Astrophysics Data System (ADS)

    Song, Young-Joo; Ho, Jin; Kim, Bang-Yeop

    2015-09-01

    Characteristics of delta-V requirements for deploying an impactor from a mother-ship at different orbital altitudes are analyzed in order to prepare for a future lunar CubeSat impactor mission. A mother-ship is assumed to be orbiting the moon with a circular orbit at a 90 deg inclination and having 50, 100, 150, 200 km altitudes. Critical design parameters that are directly related to the success of the impactor mission are also analyzed including deploy directions, CubeSat flight time, impact velocity, and associated impact angles. Based on derived delta-V requirements, required thruster burn time and fuel mass are analyzed by adapting four different miniaturized commercial onboard thrusters currently developed for CubeSat applications. As a result, CubeSat impact trajectories as well as thruster burn characteristics deployed at different orbital altitudes are found to satisfy the mission objectives. It is concluded that thrust burn time should considered as the more critical design parameter than the required fuel mass when deducing the onboard propulsion system requirements. Results provided through this work will be helpful in further detailed system definition and design activities for future lunar missions with a CubeSat-based payload.

  7. Freezing of stratospheric aerosol droplets

    NASA Astrophysics Data System (ADS)

    Luo, Beiping; Peter, Thomas; Crutzen, Paul

    Theoretical calculations are presented for homogeneous and heterogeneous freezing of sulfuric acid droplets under stratospheric conditions, based on classical nucleation theory. In contrast to previous results it is shown that a prominent candidate for freezing, sulfuric acid tetrahydrate (SAT ≡ H2SO4·4H2O), does not freeze homogeneously. The theoretical results limit the homogeneous freezing rate at 200 K to much less than 1 cm-3s-1, a value that may be estimated from bulk phase laboratory experiments. This suggests that the experimental value is likely to be a measure of heterogeneous, not homogeneous nucleation. Thus, under statospheric conditions, freezing of SAT can only occur in the presence of suitable nuclei; however, even for heterogeneous nucleation experimental results impose strong constraints. Since a nitric acid trihydrate (NAT) embryo probably needs a solid body for nucleation, these results put an important constraint on the theory of NAT formation in polar stratospheric clouds.

  8. CryoSat-2 Processing and Model Interpretation of Greenland Ice Sheet Volume Changes

    NASA Astrophysics Data System (ADS)

    Nilsson, J.; Gardner, A. S.; Sandberg Sorensen, L.

    2015-12-01

    CryoSat-2 was launched in late 2010 tasked with monitoring the changes of the Earth's land and sea ice. It carries a novel radar altimeter allowing the satellite to monitor changes in highly complex terrain, such as smaller ice caps, glaciers and the marginal areas of the ice sheets. Here we present on the development and validation of an independent elevation retrieval processing chain and respective elevation changes based on ESA's L1B data. Overall we find large improvement in both accuracy and precision over Greenland relative to ESA's L2 product when comparing against both airborne data and crossover analysis. The seasonal component and spatial sampling of the surface elevation changes where also compared against ICESat derived changes from 2003-2009. The comparison showed good agreement between the to product on a local scale. However, a global sampling bias was detected in the seasonal signal due to the clustering of CryoSat-2 data in higher elevation areas. The retrieval processing chain presented here does not correct for changes in surface scattering conditions and appears to be insensitive to the 2012 melt event (Nilsson et al., 2015). This in contrast to the elevation changes derived from ESA's L2 elevation product, which where found to be sensitive to the effects of the melt event. The positive elevation bias created by the event introduced a discrepancy between the two products with a magnitude of roughly 90 km3/year. This difference can directly be attributed to the differences in retracking procedure pointing to the importance of the retracking of the radar waveforms for altimetric volume change studies. Greenland 2012 melt event effects on CryoSat-2 radar altimetry./ Nilsson, Johan; Vallelonga, Paul Travis; Simonsen, Sebastian Bjerregaard; Sørensen, Louise Sandberg; Forsberg, René; Dahl-Jensen, Dorthe; Hirabayashi, Motohiro; Goto-Azuma, Kumiko; Hvidberg, Christine S.; Kjær, Helle A.; Satow, Kazuhide.

  9. Complementary information from TRMM and CloudSat to improve our global estimate of precipitation

    NASA Astrophysics Data System (ADS)

    Behrangi, A.; Stephens, G. L.; Adler, R. F.; Huffman, G. J.; Lambrigtsen, B.; Lebsock, M. D.

    2013-12-01

    Complementary information from CloudSat Cloud Profiling Radar (CPR), TRMM PR, and AMSR-E are used to investigate the precipitation detection and estimation performance of a suite of precipitation measuring sensors, commonly used in the production of the merged precipitation products. CPR has high sensitivity to liquid and frozen hydrometeors and can provide added information with respect to the measurement of light rain and snowfall within 80oS-80oN. PR has also enabled significant advancement in quantification of moderate to intense rainfall. The study requires careful consideration of the scale issues among different sensors that will be discussed. Furthermore, we expand the sensor-level analysis to investigate the performance of the global precipitation climatology products: GPCP and CMAP. CloudSat together with TRMM and AMSR-E are used to calculate the mean global precipitation rate and its zonal distribution through a merging process constrained by precipitation occurrence from CloudSat. The three sensors have not been used in GPCP and CMAP thus give us an independent estimate of global precipitation and can be used to understand and assess the strengths and potential weaknesses of the two products. The insights gained from the analysis are found extremely useful to guide our future updates of the products as well as to design future precipitation measuring sensors. The study highlights the important role of GPM to better detect and quantify global precipitation using its Ka/Ku band dual frequency precipitation radar (DPR) and multichannel passive microwave imager (GMI).

  10. Modelling of XCO₂ Surfaces Based on Flight Tests of TanSat Instruments.

    PubMed

    Zhang, Li Li; Yue, Tian Xiang; Wilson, John P; Wang, Ding Yi; Zhao, Na; Liu, Yu; Liu, Dong Dong; Du, Zheng Ping; Wang, Yi Fu; Lin, Chao; Zheng, Yu Quan; Guo, Jian Hong

    2016-11-01

    The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km² and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO₂) surface based on flight test data which measured the near- and short-wave infrared (NIR) reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO₂ in the flight area using the limited flight test data and the approximate surface of XCO₂, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM) platform to fill the gaps where there is no information on XCO₂ in the flight test area, which takes the approximate surface of XCO₂ as its driving field and the XCO₂ observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO₂ were constructed with HASM based on the flight's observations. The results showed that the mean XCO₂ in the flight test area is about 400 ppm and that XCO₂ over urban areas is much higher than in other places. Compared with OCO-2's XCO₂, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO₂ surface based on the flight test of the TanSat instruments fell within an expected and acceptable range.

  11. Improving the Arctic Mean Sea Surface with CryoSat-2 Data

    NASA Astrophysics Data System (ADS)

    Stenseng, L.; Andersen, O. B.

    2013-12-01

    A fundamental basis for estimating short and long-term changes in the sea surface is a reliable mean sea surface (MSS). Existing MSS models, derived from satellite radar altimetry, generally lack observations above 82 degrees latitude making high Arctic sea surface change estimates unreliable. Most current MSS models use ICESat data, geoid models, ocean circulation models, or a combination of these to extrapolate the MSS above 82 degrees latitude. This approach makes the MSS models unsuited for deriving sea surface anomalies from short-term observations like airborne campaigns (e.g. operation IceBridge). The new state of the art DTU13MSS is a global high-resolution MSS that includes retracked CryoSat-2 data and thereby extends the polar data coverage up to 88 degrees latitude. Furthermore, in the sea-ice covered areas, the SAR and SARin feature of the altimeter on-board CryoSat-2 increases the amount of useable observations dramatically compared to conventional altimeters like ENVISAT and ERS-1/2. Finally the continuous time-series, below 82 degrees latitude, has been extended to cover more than 20 years compared to the 17 years use for the DTU10MSS model. A comparison between DTU13MSS and DTU10MSS show an improvement of more than 20 cm between 82 and 88 degrees latitude. For the first time the three years of retracked CryoSat-2 data will, in combination with DTU13MSS, allow reliable estimation of the trend and annual variations in the high Arctic Ocean sea surface height.

  12. Cold Season QPF: Sensitivities to Snow Parameterizations and Comparisons to NASA CloudSat Observations

    NASA Technical Reports Server (NTRS)

    Molthan, A. L.; Haynes, J. A.; Jedlovec, G. L.; Lapenta, W. M.

    2009-01-01

    As operational numerical weather prediction is performed at increasingly finer spatial resolution, precipitation traditionally represented by sub-grid scale parameterization schemes is now being calculated explicitly through the use of single- or multi-moment, bulk water microphysics schemes. As computational resources grow, the real-time application of these schemes is becoming available to a broader audience, ranging from national meteorological centers to their component forecast offices. A need for improved quantitative precipitation forecasts has been highlighted by the United States Weather Research Program, which advised that gains in forecasting skill will draw upon improved simulations of clouds and cloud microphysical processes. Investments in space-borne remote sensing have produced the NASA A-Train of polar orbiting satellites, specially equipped to observe and catalog cloud properties. The NASA CloudSat instrument, a recent addition to the A-Train and the first 94 GHz radar system operated in space, provides a unique opportunity to compare observed cloud profiles to their modeled counterparts. Comparisons are available through the use of a radiative transfer model (QuickBeam), which simulates 94 GHz radar returns based on the microphysics of cloudy model profiles and the prescribed characteristics of their constituent hydrometeor classes. CloudSat observations of snowfall are presented for a case in the central United States, with comparisons made to precipitating clouds as simulated by the Weather Research and Forecasting Model and the Goddard single-moment microphysics scheme. An additional forecast cycle is performed with a temperature-based parameterization of the snow distribution slope parameter, with comparisons to CloudSat observations provided through the QuickBeam simulator.

  13. Uncertain Ground: Mapping Errors through the POM-SAT Model of Paleoclimatic Reconstruction

    NASA Astrophysics Data System (ADS)

    Bartlett, M. G.

    2011-12-01

    Borehole temperature-depth profiles contain information about the ground surface temperatures (GST) history of a locale and can be useful in climate change detection and quantification. The borehole method of climate reconstruction assumes that the dominant heat transport mechanism in the upper few hundred meters of the earth's crust is conduction; mathematically, conduction is a compressive (information losing) mapping from the space of GST to the temperature-depth profile (T-z). Because the mapping is compressive, multiple GST histories can map into the same T-z profile; the solution suffers from non-uniqueness. One means of dealing with the non-uniqueness problem is to limit the number of parameters sought in the solution space. However, even when only a single parameter (the pre-observation mean GST, or POM) is sought in the inversion, a certain amount of a priori information must be introduced including the surface-air temperature history (SAT), the thermal parameterization of the ground medium, and the background (non-climatic) heat flux. I perform a set of Monte Carlo analyses to investigate how uncertainties in these a priori model parameters are mapped into the solution space of the POM-SAT method of climate reconstruction from borehole data. Results indicate that uncertainties in the SAT time series and thermal parameterization of the ground are generally reduced by an order of magnitude, though a significant non-linearity is introduced by the model which can lead to erroneous solutions for large magnitudes of actual warming or cooling. More problematically, uncertainties in the background (non-climatic) thermal regime are magnified by an order of magnitude in the solution-space. These results suggest a degree of prudence should be exercised in interpreting surface temperature histories from borehole data.

  14. Modelling of XCO2 Surfaces Based on Flight Tests of TanSat Instruments

    PubMed Central

    Zhang, Li Li; Yue, Tian Xiang; Wilson, John P.; Wang, Ding Yi; Zhao, Na; Liu, Yu; Liu, Dong Dong; Du, Zheng Ping; Wang, Yi Fu; Lin, Chao; Zheng, Yu Quan; Guo, Jian Hong

    2016-01-01

    The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km2 and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO2) surface based on flight test data which measured the near- and short-wave infrared (NIR) reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO2 in the flight area using the limited flight test data and the approximate surface of XCO2, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM) platform to fill the gaps where there is no information on XCO2 in the flight test area, which takes the approximate surface of XCO2 as its driving field and the XCO2 observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO2 were constructed with HASM based on the flight’s observations. The results showed that the mean XCO2 in the flight test area is about 400 ppm and that XCO2 over urban areas is much higher than in other places. Compared with OCO-2’s XCO2, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO2 surface based on the flight test of the TanSat instruments fell within an expected and acceptable range. PMID:27809272

  15. NASA's Physics of the Cosmos and Cosmic Origins programs manage Strategic Astrophysics Technology (SAT) development

    NASA Astrophysics Data System (ADS)

    Pham, Thai; Thronson, Harley; Seery, Bernard; Ganel, Opher

    2016-07-01

    The strategic astrophysics missions of the coming decades will help answer the questions "How did our universe begin and evolve?" "How did galaxies, stars, and planets come to be?" and "Are we alone?" Enabling these missions requires advances in key technologies far beyond the current state of the art. NASA's Physics of the Cosmos2 (PCOS), Cosmic Origins3 (COR), and Exoplanet Exploration Program4 (ExEP) Program Offices manage technology maturation projects funded through the Strategic Astrophysics Technology (SAT) program to accomplish such advances. The PCOS and COR Program Offices, residing at the NASA Goddard Space Flight Center (GSFC), were established in 2011, and serve as the implementation arm for the Astrophysics Division at NASA Headquarters. We present an overview of the Programs' technology development activities and the current technology investment portfolio of 23 technology advancements. We discuss the process for addressing community-provided technology gaps and Technology Management Board (TMB)-vetted prioritization and investment recommendations that inform the SAT program. The process improves the transparency and relevance of our technology investments, provides the community a voice in the process, and promotes targeted external technology investments by defining needs and identifying customers. The Programs' priorities are driven by strategic direction from the Astrophysics Division, which is informed by the National Research Council's (NRC) "New Worlds, New Horizons in Astronomy and Astrophysics" (NWNH) 2010 Decadal Survey report [1], the Astrophysics Implementation Plan (AIP) [2] as updated, and the Astrophysics Roadmap "Enduring Quests, Daring Visions" [3]. These priorities include technology development for missions to study dark energy, gravitational waves, X-ray and inflation probe science, and large far-infrared (IR) and ultraviolet (UV)/optical/IR telescopes to conduct imaging and spectroscopy studies. The SAT program is the

  16. Overcoming CubeSat downlink limits with vitamin: A new variable coded modulation protocol

    NASA Astrophysics Data System (ADS)

    Sielicki, Thomas A.

    Many space missions, including low earth orbit CubeSats, communicate in a highly dynamic environment because of variations in geometry, weather, and interference. At the same time, most missions communicate using fixed channel codes, modulations, and symbol rates, resulting in a constant data rate that does not adapt to the dynamic conditions. When conditions are good, the fixed date rate can be far below the theoretical maximum, called the Shannon limit; when conditions are bad, the fixed data rate may not work at all. To move beyond these fixed communications and achieve higher total data volume from emerging high-tech instruments, this thesis investigates the use of error correcting codes and different modulations. Variable coded modulation (VCM) takes advantage of the dynamic link by transmitting more information when the signal-to-noise ratio (SNR) is high. Likewise, VCM can throttle down the information rate when SNR is low without having to stop all communications. VCM outperforms fixed communications which can only operate at a fixed information rate as long as a certain signal threshold is met. This thesis presents a new VCM protocol and tests its performance in both software and hardware simulations. The protocol is geared towards CubeSat downlinks as complexity is focused in the receiver, while the transmission operations are kept simple. This thesis explores bin-packing as a way to optimize the selection of VCM modes based on expected SNR levels over time. Working end-to-end simulations were created using MATLAB and LabVIEW, while the hardware simulations were done with software defined radios. Results show that a CubeSat using VCM communications will deliver twice the data throughput of a fixed communications system.

  17. The role of dietary fatty acids in predicting myocardial structure in fat-fed rats

    PubMed Central

    2011-01-01

    Background Obesity increases the risk for development of cardiomyopathy in the absence of hypertension, diabetes or myocardial ischemia. Not all obese individuals, however, progress to heart failure. Indeed, obesity may provide protection from cardiovascular mortality in some populations. The fatty acid milieu, modulated by diet, may modify obesity-induced myocardial structure and function, lending partial explanation for the array of cardiomyopathic phenotypy in obese individuals. Methods Adult male Sprague-Dawley rats were fed 1 of the following 4 diets for 32 weeks: control (CON); 50% saturated fat (SAT); 40% saturated fat + 10% linoleic acid (SAT+LA); 40% saturated fat + 10% α-linolenic acid (SAT+ALA). Serum leptin, insulin, glucose, free fatty acids and triglycerides were quantitated. In vivo cardiovascular outcomes included blood pressure, heart rate and echocardiographic measurements of structure and function. The rats were sacrificed and myocardium was processed for fatty acid analysis (TLC-GC), and evaluation of potential modifiers of myocardial structure including collagen (Masson's trichrome, hydroxyproline quantitation), lipid (Oil Red O, triglyceride quantitation) and myocyte cross sectional area. Results Rats fed SAT+LA and SAT+ALA diets had greater cranial LV wall thickness compared to rats fed CON and SAT diets, in the absence of hypertension or apparent insulin resistance. Treatment was not associated with changes in myocardial function. Myocardial collagen and triglycerides were similar among treatment groups; however, rats fed the high-fat diets, regardless of composition, demonstrated increased myocyte cross sectional area. Conclusions Under conditions of high-fat feeding, replacement of 10% saturated fat with either LA or ALA is associated with thickening of the cranial LV wall, but without concomitant functional changes. Increased myocyte size appears to be a more likely contributor to early LV thickening in response to high-fat feeding

  18. Xatcobeo: Small Mechanisms for CubeSat Satellites - Antenna and Solar Array Deployment

    NASA Technical Reports Server (NTRS)

    EncinasPlaza, Jose Miguel; VilanVilan, Jose Antonio; AquadoAgelet, Fernando; BrandiaranMancheno, Javier; LopezEstevez, Miguel; MartinezFernandez, Cesar; SarmientoAres, Fany

    2010-01-01

    The Xatcobeo project, which includes the mechanisms dealt with here, is principally a university project to design and construct a CubeSat 1U-type satellite. This work describes the design and operational features of the system for antenna storage and deployment, and the design and simulations of the solar array deployment system. It explains the various problems faced and solutions adopted, with a view to providing valid data for any other applications that could find them useful, be they of a similar nature or not.

  19. Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2

    NASA Astrophysics Data System (ADS)

    Helm, V.; Humbert, A.; Miller, H.

    2014-03-01

    The ESA satellite CryoSat-2 has been observing Earth's polar regions since April 2010. It carries a sophisticated radar altimeter and aims for the detection of changes in sea ice thickness as well as surface elevation changes of Earth's land and marine ice sheets. This study focuses on the Greenland and Antarctic ice sheets, considering the contemporary elevation of their surfaces. Based on 2 years of CryoSat-2 data acquisition, elevation change maps and mass balance estimates are presented. Additionally, new digital elevation models (DEMs) and the corresponding error maps are derived. Due to the high orbit of CryoSat-2 (88° N/S) and the narrow across-track spacing, more than 99% of Antarctica's surface area is covered. In contrast, previous radar altimeter measurements of ERS1/2 and ENVISAT were limited to latitudes between 81.5° N and 81.5° S and to surface slopes below 1°. The derived DEMs for Greenland and Antarctica have an accuracy which is similar to previous DEMs obtained by satellite-based laser and radar altimetry (Liu et al., 2001; Bamber et al., 2009, 2013; Fretwell et al., 2013; Howat et al., 2014). Comparisons with ICESat data show that 80% of the CryoSat-2 DEMs have an error of less than 3 m ± 30 m. For both ice sheets the surface elevation change rates between 2011 and 2012 are presented at a resolution of 1 km. Negative elevation changes are concentrated at the west and south-east coast of Greenland and in the Amundsen Sea embayment in West Antarctica (e.g. Pine Island and Thwaites glaciers). They agree well with the dynamic mass loss observed by ICESat between 2003 and 2008 (Pritchard et al., 2009). Thickening occurs along the main trunk of Kamb Ice Stream and in Dronning Maud Land. While the former is a consequence of an ice stream stagnated ∼150 years ago (Rose, 1979; Retzlaff and Bentley, 1993), the latter represents a known large-scale accumulation event (Lenaerts et al., 2013). This anomaly partly compensates for the observed

  20. Modelling suspended sediment distribution in the Selenga River Delta using LandSat data

    NASA Astrophysics Data System (ADS)

    Chalov, Sergey R.; Bazilova, Varvara O.; Tarasov, Mikhail K.

    2017-03-01

    The Selenga River is the largest tributary of Baikal Lake and it's delta covers around 600 km2. Suspended sediment concentrations (SSC) in the Selenga river delta were modelled based on LandSat images data. The seasonal variability in suspended sediment retention during the period 1989 to 2015 was calculated. The results suggest that sediment storage in the Selenga delta is observed during high discharges (> 1500 m3 s-1), whereas sediment export increases under lower flow conditions (< 1500 m3 s-1). The changes in seasonal SSC patterns are explained by wetland inundation during floods and channel erosion or Baikal wind surge during low flow periods.

  1. Estimation of Arctic Sea Ice Freeboard and Thickness Using CryoSat-2

    NASA Astrophysics Data System (ADS)

    Lee, S.; Im, J.; Kim, J. W.; Kim, M.; Shin, M.

    2014-12-01

    Arctic sea ice is one of the significant components of the global climate system as it plays a significant role in driving global ocean circulation. Sea ice extent has constantly declined since 1980s. Arctic sea ice thickness has also been diminishing along with the decreasing sea ice extent. Because extent and thickness, two main characteristics of sea ice, are important indicators of the polar response to on-going climate change. Sea ice thickness has been measured with numerous field techniques such as surface drilling and deploying buoys. These techniques provide sparse and discontinuous data in spatiotemporal domain. Spaceborne radar and laser altimeters can overcome these limitations and have been used to estimate sea ice thickness. Ice Cloud and land Elevation Satellite (ICEsat), a laser altimeter provided data to detect polar area elevation change between 2003 and 2009. CryoSat-2 launched with Synthetic Aperture Radar (SAR)/Interferometric Radar Altimeter (SIRAL) in April 2010 can provide data to estimate time-series of Arctic sea ice thickness. In this study, Arctic sea ice freeboard and thickness between 2011 and 2014 were estimated using CryoSat-2 SAR and SARIn mode data that have sea ice surface height relative to the reference ellipsoid WGS84. In order to estimate sea ice thickness, freeboard, i.e., elevation difference between the top of sea ice surface should be calculated. Freeboard can be estimated through detecting leads. We proposed a novel lead detection approach. CryoSat-2 profiles such as pulse peakiness, backscatter sigma-0, stack standard deviation, skewness and kurtosis were examined to distinguish leads from sea ice. Near-real time cloud-free MODIS images corresponding to CryoSat-2 data measured were used to visually identify leads. Rule-based machine learning approaches such as See5.0 and random forest were used to identify leads. The proposed lead detection approach better distinguished leads from sea ice than the existing approaches

  2. CryoSat-2: Post launch performance of SIRAL-2 and its calibration/validation

    NASA Astrophysics Data System (ADS)

    Cullen, Robert; Francis, Richard; Davidson, Malcolm; Wingham, Duncan

    2010-05-01

    1. INTRODUCTION The main payload of CryoSat-2 [1], SIRAL (Synthetic interferometric radar altimeter), is a Ku band pulse-width limited radar altimeter which transmits pulses at a high pulse repetition frequency thus making received echoes phase coherent and suitable for azimuth processing [2]. The azimuth processing in conjunction with correction for slant range improves along track resolution to about 250 meters which is a significant improvement over traditional pulse-width limited systems such as Envisat RA-2, [3]. CryoSat-2 will be launched on 25th February 2010 and this paper describes the pre and post launch measures of CryoSat/SIRAL performance and the status of mission validation planning. 2. SIRAL PERFORMANCE: INTERNAL AND EXTERNAL CALIBRATION Phase coherent pulse-width limited radar altimeters such as SIRAL-2 pose a new challenge when considering a strategy for calibration. Along with the need to generate the well understood corrections for transfer function amplitude with respect to frequency, gain and instrument path delay there is also a need to provide corrections for transfer function phase with respect to frequency and AGC setting, phase variation across bursts of pulses. Furthermore, since some components of these radars are temperature sensitive one needs to be careful when the deciding how often calibrations are performed whilst not impacting mission performance. Several internal calibration ground processors have been developed to model imperfections within the CryoSat-2 radar altimeter (SIRAL-2) hardware and reduce their effect from the science data stream via the use of calibration correction auxiliary products within the ground segment. We present the methods and results used to model and remove imperfections and describe the baseline for usage of SIRAL-2 calibration modes during the commissioning phase and the operational exploitation phases of the mission. Additionally we present early results derived from external calibration of SIRAL via

  3. NASA Launch Services Program - Project ELaNa and Educational CubeSat Initiative

    NASA Technical Reports Server (NTRS)

    Skrobot, Garrett Lee

    2010-01-01

    This slide presentation reviews the NASA program to use expendable lift vehicles (ELVs) to launch nanosatellites for the purpose of enhancing educational research. The Education Launch of Nanosatellite (ELaNa) project, run out of the Launch Services Program is requesting proposals for CubeSat type payload to provide information that will aid or verify NASA Projects designs while providing higher educational research opportunities. Information is included about the launch vehicles, launch sites that are available to support the Poly Picosatellite Orbital Developer System (PPOD) that could be used on the available ELVs. There is an overview of the services that are provided for a launch.

  4. Formal Modeling and Analysis of a Preliminary Small Aircraft Transportation System (SATS)Concept

    NASA Technical Reports Server (NTRS)

    Carrreno, Victor A.; Gottliebsen, Hanne; Butler, Ricky; Kalvala, Sara

    2004-01-01

    New concepts for automating air traffic management functions at small non-towered airports raise serious safety issues associated with the software implementations and their underlying key algorithms. The criticality of such software systems necessitates that strong guarantees of the safety be developed for them. In this paper we present a formal method for modeling and verifying such systems using the PVS theorem proving system. The method is demonstrated on a preliminary concept of operation for the Small Aircraft Transportation System (SATS) project at NASA Langley.

  5. HyperCube: a hyperspectral CubeSat constellation for measurements of 3D winds

    NASA Astrophysics Data System (ADS)

    Glumb, Ronald; Lapsley, Michael; Luce, Scott; Déry, Jean-Philippe; Scott, Deron; Nielsen, Tim

    2016-09-01

    Global measurements of vertically resolved atmospheric wind profiles offer the potential for improved weather forecasts and superior predictions of atmospheric wind patterns. Harris' HyperCube constellation of twelve 6U hyperspectral CubeSats can provide measurements of global tropospheric wind profiles from space at very low cost. It is a commercially funded enterprise in which the data from the satellites is provided to users on a subscription basis. This requires that the design of each satellite be optimized for minimum cost, yet with a reasonably long service life. This paper will focus on the design, operations, and projected performance of the HyperCube system.

  6. The DeMi CubeSat: Wavefront Control with a MEMS Deformable Mirror in Space

    NASA Astrophysics Data System (ADS)

    Douglas, Ewan S.; Bendek, Eduardo; Marinan, Anne; Belikov, Ruslan; Merck, John; Cahoy, Kerri Lynn

    2017-01-01

    High-contrast imaging instruments on future space telescopes will require precise wavefront correction to detect small exoplanets near their host stars. High-actuator count microelectromechanical system (MEMS) deformable mirrors provide a compact form of wavefront control. The 6U DeMi CubeSat will demonstrate wavefront control with a MEMS deformable mirror over a yearlong mission. The payload includes both an internal laser source and a small telescope, with both focal plane and pupil plane sensing, for deformable mirror characterization. We detail the DeMi payload design, and describe future astrophysics enabled by high-actuator count deformable mirrors and small satellites.

  7. Mapping distortion of detectors in UVIT onboard AstroSat observatory

    NASA Astrophysics Data System (ADS)

    Girish, V.; Tandon, Shyam N.; Sriram, S.; Kumar, Amit; Postma, Joe

    2017-02-01

    Ultraviolet Imaging Telescope (UVIT) is one of the payloads onboard AstroSat, India's first multi-wavelength Astronomy mission. UVIT is primarily designed to make high resolution images in wide field, in three wavelength channels simultaneously: FUV (130-180 nm), NUV (200-300 nm) and VIS (320-550 nm). The intensified imagers used in UVIT suffer from distortions, and a correction is necessary for these to achieve good astrometry. In this article we describe the methodology and calculations used to estimate the distortions in ground calibrations.

  8. NASA's Participation in Joint SatOPS Compatibility Efforts 2009-2010

    NASA Technical Reports Server (NTRS)

    Smith, Danford

    2010-01-01

    Many U.S. government organizations build or fly space systems: a) NASA, NOAA, Navy, Air Force, NRO, ORS. Others? b) Through the Joint SatOps Compatibility Committee (JSCC) we have increased the grass-roots interaction between many of these organizations. c) We all deal with many of the same challenges: More rapid deployments, lower budgets; Advancing technologies - frameworks, clouds, virtualization; Evolving concepts - automation, situational awareness, enterprise mngt. Standardization - formal or by common use. There is an inherently governmental role in creating the business case for contractors and commercial product vendors to move in directions beneficial to multiple government space organizations.

  9. The Brazilian INPE-UFSM NANOSATC-BR CubeSat Development Capacity Building Program

    NASA Astrophysics Data System (ADS)

    Schuch, Nelson Jorge; Cupertino Durao, Otavio S.

    The Brazilian INPE-UFSM NANOSATC-BR CubeSat Development Capacity Building Program (CBP) and the results of the NANOSATC-BR1, the first Brazilian CubeSat launching, expected for 2014's first semester, are presented. The CBP consists of two CubeSats, NANOSATC-BR 1 (1U) & 2 (2U) and is expected operate in orbit for at least 12 months each, with capacity building in space science, engineering and computer sciences for the development of space technologies using CubeSats satellites. The INPE-UFSM’s CBP Cooperation is basically among: (i) the Southern Regional Space Research Center (CRS), from the Brazilian INPE/MCTI, where acts the Program's General Coordinator and Projects NANOSATC-BR 1 & 2 Manager, having technical collaboration and management of the Mission’s General Coordinator for Engineering and Space Technology at INPE’s Headquarter (HQ), in São José dos Campos, São Paulo; (ii) the Santa Maria Space Science Laboratory (LACESM/CT) from the Federal University of Santa Maria - (UFSM); (iii) the Santa Maria Design House (SMDH); (iv) the Graduate Program in Microelectronics from the Federal University of Rio Grande do Sul (MG/II/UFRGS); and (v) the Aeronautic Institute of Technology (ITA/DCTA/CA-MD). The INPE-UFSM’s CBP has the involvement of UFSM' undergraduate students and graduate students from: INPE/MCTI, MG/II/UFRGS and ITA/DCTA/CA-MD. The NANOSATC-BR 1 & 2 Projects Ground Stations (GS) capacity building operation with VHF/UHF band and S-band antennas, are described in two specific papers at this COSPAR-2014. This paper focuses on the development of NANOSATC-BR 1 & 2 and on the launching of NANOSATC-BR1. The Projects' concepts were developed to: i) monitor, in real time, the Geospace, the Ionosphere, the energetic particle precipitation and the disturbances at the Earth's Magnetosphere over the Brazilian Territory, and ii) the determination of their effects on regions such as the South American Magnetic Anomaly (SAMA) and the Brazilian sector of the

  10. Extrapolating the Results of DICE to Constellation CubeSat Missions for Space Science

    NASA Astrophysics Data System (ADS)

    Swenson, C.; Fish, C. S.; Crowley, G.; Gunther, J.

    2012-12-01

    One of the most promising observation strategies still to be developed to advance space science is the capability to conduct simultaneous multipoint observations of the Earth system from space. These types of observations are required to understand the "big picture" of coupling between disparate regions: solar-wind, magnetosphere, ionosphere, thermosphere, mesosphere, atmosphere, land, ocean on a planetary scale. Affordable large constellations of scientific "space-buoys" can only be achieved through miniature spacecraft such as CubeSats due to the high cost of launching larger spacecraft. What has not yet been explored is how constellations of such satellites can be made effective for multipoint scientific studies. To be effective the architecture must: 1) Allow large amounts, Gigabits of data per day, of scientific data to be retrieved from the constellation and, 2) Address the orbital configuration and control of the constellation. The communications architecture, in which a constellation of "space-buoys" that are size, weight and power constrained addresses these needs, is lacking. The "Dynamic Ionosphere CubeSat Experiment" or "DICE" mission was selected and funded by the National Science Foundation in October 2009 in response to a cooperative proposal from ASTRA LLC, Utah State University's Space Dynamics Laboratory (USU/SDL), and Embry Riddle University. DICE consists of two identical "CubeSats" launched on October 27, 2011 as secondary payloads from a Delta II rocket and released into an 809 to 457 km at 102° inclination with one satellite chasing the other. The DICE mission is not using traditional CubeSat communications systems, but is instead using government radio bands and high speed downlink rates that are consistent with a NSF funded mission. A half-duplex UHF modem developed for DICE provides a 3 Mbit/s downlink and a 19.2 kbit/s uplink. The ground stations are located at Wallops Island on the east coast and/or at SRI on the west coast. In this

  11. A New Lower Bound on the Maximum Number of Satisfied Clauses in Max-SAT and Its Algorithmic Application

    NASA Astrophysics Data System (ADS)

    Crowston, Robert; Gutin, Gregory; Jones, Mark; Yeo, Anders

    For a formula F in conjunctive normal form (CNF), let sat(F) be the maximum number of clauses of F that can be satisfied by a truth assignment, and let m be the number of clauses in F. It is well-known that for every CNF formula F, sat(F) ≥ m/2 and the bound is tight when F consists of conflicting unit clauses (x) and (bar{x}). Since each truth assignment satisfies exactly one clause in each pair of conflicting unit clauses, it is natural to reduce F to the unit-conflict free (UCF) form. If F is UCF, then Lieberherr and Specker (J. ACM 28(2):411-421, 1981) proved that sat(F)ge {hat{φ}} m, where {hat{φ}} =(sqrt{5}-1)/2.

  12. A CubeSat for Calibrating Ground-Based and Sub-Orbital Millimeter-Wave Polarimeters

    NASA Astrophysics Data System (ADS)

    Johnson, Bradley

    2016-06-01

    We describe a low-cost, open-access, CubeSat-based calibration instrument that is designed to support ground-based and sub-orbital experiments searching for various polarization signals in the cosmic microwave background (CMB). All modern CMB polarization experiments require a robust calibration program that will allow the effects of instrument-induced signals to be mitigated during data analysis. A bright, compact, and linearly polarized astrophysical source with polarization properties known to adequate precision does not exist. Therefore, we designed a space-based millimeter-wave calibration instrument, called CalSat, to serve as an open-access calibrator, and this paper describes the results of our design study. The calibration source on board CalSat is composed of five "tones'" with one each at 47.1, 80.0, 140, 249 and 309 GHz. The five tones we chose are well matched to (i) the observation windows in the atmospheric transmittance spectra, (ii) the spectral bands commonly used in polarimeters by the CMB community, and (iii) The Amateur Satellite Service bands in the Table of Frequency Allocations used by the Federal Communications Commission. CalSat will be placed in a polar orbit allowing visibility from observatories in the Northern Hemisphere, such as Mauna~Kea in Hawaii and Summit Station in Greenland, and the Southern Hemisphere, such as the Atacama Desert in Chile and the South Pole. CalSat also will be observable by balloon-borne instruments launched from a range of locations around the world. This global visibility makes CalSat the only source that can be observed by all terrestrial and sub-orbital observatories, thereby providing a universal standard that permits comparison between experiments using appreciably different measurement approaches.

  13. Investigating the Utility of Swath Mode CryoSat Data for Determining Ice Sheet Grounding Line Locations

    NASA Astrophysics Data System (ADS)

    Hogg, A. E.; Shepherd, A.; Gourmelen, N.; Foresta, L.

    2014-12-01

    Surface elevation measurements derived from Swath Mode processing of CryoSat data are examined to determine their utility for measuring ice sheet grounding line locations. Ice sheet grounding lines are the boundary between floating ice in hydrostatic equilibrium with the ocean, and grounded glacial ice. In reality grounding lines are a transitory feature with a location that can fluctuate on short, sub-daily timescales due to the effect of ocean tides, and long, decadal timescales due to the effect of ice mass loss. Grounding line retreat is a key indicator of change in mass balance and internal instability in marine terminating ice masses therefore it is important to develop new techniques to measure change in this important geophysical parameter. As part of the ESA STSE CryoTop project, Synthetic Aperture Radar Interferometer (SARIn) mode CryoSat data was processed in 'Swath Mode', which uses the full altimeter waveform to retrieve surface elevation measurements at a fine spatial resolution across the CryoSat ground track. This results in a narrow digital elevation model for each CryoSat ground track with a high density of points relative to traditional pulse limited altimetry. As part of the ESA STSE GLITter project, Swath Mode CryoSat data was differenced from tracks acquired at different times. The resulting surface elevation difference is caused by variation in the ocean tide amplitude which we use here to determine the ice sheet grounding line location. Our CryoSat grounding line location result is inter-compared with a cotemporaneous grounding line location derived from the established technique of differential interferometry (DInSAR).

  14. Towards Disentangling Natural and Anthropogenic GHG Fluxes from Space - The CarbonSat Earth Explorer 8 Candidate Mission

    NASA Astrophysics Data System (ADS)

    Bovensmann, H.; Buchwitz, M.; Reuter, M.; Gerilowski, K.; Krings, T.; Burrows, J. P.; Crisp, D.; Boesch, H.; Brunner, D.; Ciais, P.; Bréon, F. M.; Dolman, A. J.; Hayman, G.; Houweling, S.; Lichtenberg, G.; Ingmann, P.; Sierk, B.; Loescher, A.; Meijer, Y.

    2014-12-01

    CarbonSat was selected by ESA as one of two candidates for the Earth Explorer Opportunity mission (EE8). Understanding and quantifying climate feedback and forcing mechanisms involving the two most important anthropogenic greenhouse gases, CO2 and CH4, requires the discrimination of natural and anthropogenic CO2 and CH4 fluxes globally, with regional to local spatial scale resolution. The objective of the CarbonSat mission is therefore to quantify natural and anthropogenic sources and sinks of CO2 and CH4. The unique feature of the CarbonSat mission concept is its "GHG imaging capability", which is achieved by combining high spatial resolution (6 km2) and good spatial coverage (breakthrough: 240 km swath, contiguous ground sampling). This capability enables global imaging of localized strong emission source areas such as cities, power plants, methane seeps, landfills and volcanoes and better separation of natural and anthropogenic GHG sources and sinks. The latter will be further supported by CarbonSat's ability to constrain the fluxes of CO2 exchanged to and from the land biosphere by simultaneously measuring CO2 and sun induced chlorophyll fluorescence (SIF), a process strongly associated with Gross Primary Production (GPP). Source/sink information will be derived from the retrieved atmospheric column-averaged mole fractions of CO2 and CH4 via inverse modelling. CarbonSat aims to deliver spatially-resolved time varying global estimates of dry column mixing ratios of CO2 and CH4 with high precision (~1 to 2 ppm and ~12 ppb, respectively) and rel. accuracy (~0.5 ppm and 5 ppb, respectively). Benefiting from its imaging capabilities along and across track, CarbonSat will provide at least an order of magnitude larger number of cloud-free CO2 soundings than GOSAT and OCO-2. Recent results from the scientific studies and supporting campaigns documenting the expected data quality and potential application areas will be presented.

  15. Towards Disentangling Natural and Anthropogenic GHG Fluxes from Space - The CarbonSat Earth Explorer 8 Candidate Mission

    NASA Astrophysics Data System (ADS)

    Bovensmann, Heinrich

    2015-04-01

    CarbonSat was selected by ESA as one of two candidates for the Earth Explorer Opportunity mission (EE8). Understanding and quantifying climate feedback and forcing mechanisms involving the two most important anthropogenic greenhouse gases, CO2 and CH4, requires the discrimination of natural and anthropogenic CO2 and CH4 fluxes globally, with regional to local spatial scale resolution. The objective of the CarbonSat mission is therefore to quantify natural and anthropogenic sources and sinks of CO2 and CH4. The unique feature of the CarbonSat mission concept is its 'GHG imaging capability', which is achieved by combining high spatial resolution (6 km2) and good spatial coverage (breakthrough: 240 km swath, contiguous ground sampling). This capability enables global imaging of localized strong emission source areas such as cities, power plants, methane seeps, landfills and volcanoes and better separation of natural and anthropogenic GHG sources and sinks. The latter will be further supported by CarbonSat's ability to constrain the fluxes of CO2 exchanged to and from the land biosphere by simultaneously measuring CO2 and sun induced chlorophyll fluorescence (SIF), a process strongly associated with Gross Primary Production (GPP). Source/sink information will be derived from the retrieved atmospheric column-averaged mole fractions of CO2 and CH4 via inverse modelling. CarbonSat aims to deliver spatially-resolved time varying global estimates of dry column mixing ratios of CO2 and CH4 with high precision (~1 to 2 ppm and ~12 ppb, respectively) and rel. accuracy (~0.5 ppm and 5 ppb, respectively). Benefiting from its imaging capabilities along and across track, CarbonSat will provide at least an order of magnitude larger number of cloud-free CO2 soundings than GOSAT and OCO-2. Recent results from the scientific studies and supporting campaigns documenting the expected data quality and potential application areas will be summarised.

  16. The Small Aircraft Transportation System (SATS), Higher Volume Operations (HVO) Off-Nominal Operations

    NASA Technical Reports Server (NTRS)

    Baxley, B.; Williams, D.; Consiglio, M.; Conway, S.; Adams, C.; Abbott, T.

    2005-01-01

    The ability to conduct concurrent, multiple aircraft operations in poor weather, at virtually any airport, offers an important opportunity for a significant increase in the rate of flight operations, a major improvement in passenger convenience, and the potential to foster growth of charter operations at small airports. The Small Aircraft Transportation System, (SATS) Higher Volume Operations (HVO) concept is designed to increase traffic flow at any of the 3400 nonradar, non-towered airports in the United States where operations are currently restricted to one-in/one-out procedural separation during Instrument Meteorological Conditions (IMC). The concept's key feature is pilots maintain their own separation from other aircraft using procedures, aircraft flight data sent via air-to-air datalink, cockpit displays, and on-board software. This is done within the Self-Controlled Area (SCA), an area of flight operations established during poor visibility or low ceilings around an airport without Air Traffic Control (ATC) services. The research described in this paper expands the HVO concept to include most off-nominal situations that could be expected to occur in a future SATS environment. The situations were categorized into routine off-nominal operations, procedural deviations, equipment malfunctions, and aircraft emergencies. The combination of normal and off-nominal HVO procedures provides evidence for an operational concept that is safe, requires little ground infrastructure, and enables concurrent flight operations in poor weather.

  17. Lazy Clause Generation: Combining the Power of SAT and CP (and MIP?) Solving

    NASA Astrophysics Data System (ADS)

    Stuckey, Peter J.

    Finite domain propagation solving, the basis of constraint programming (CP) solvers, allows building very high-level models of problems, and using highly specific inference encapsulated in complex global constraints, as well as programming the search for solutions to take into account problem structure. Boolean satisfiability (SAT) solving allows the construction of a graph of inferences made in order to determine and record effective nogoods which prevent the searching of similar parts of the problem, as well as the determination of those variables which form a tightly connected hard part of the problem, thus allowing highly effective automatic search strategies concentrating on these hard parts. Lazy clause generation is a hybrid of CP and SAT solving that combines the strengths of the two approaches. It provides state-of-the-art solutions for a number of hard combinatorial optimization and satisfaction problems. In this invited talk we explain lazy clause generation, and explore some of the many design choices in building such a hybrid system, we also discuss how to further incorporate mixed integer programming (MIP) solving to see if we can also inherit its advantages in combinatorial optimization.

  18. BurstCube: A CubeSat for Gravitational Wave Counterparts

    NASA Astrophysics Data System (ADS)

    Racusin, Judith L.; Perkins, Jeremy S.; Briggs, Michael Stephen; De Nolfo, Georgia; Krizmanic, John; Connaughton, Valerie; McEnery, Julie E.

    2016-01-01

    We present BurstCube, a novel CubeSat that will detect and localize Gamma-ray Bursts (GRBs). BurstCube will detect both long GRBs attributed to the collapse of massive stars, and short GRBs that are the result of a binary neutron star merger, which are also predicted to be the counterparts of gravitational wave sources soon to be detectable by advanced LIGO/Virgo, as well as other gamma-ray (10-1000 keV) transients. BurstCube contains 4 CsI scintillators coupled with arrays of compact low-power Silicon photomultipliers (SiPMs) on a 6U CubeSat incorporating in-house front-end electronics for large-area arrays of SiPMs, off-the-shelf spacecraft components and a straightforward design and implementation. BurstCube will potentially complement existing facilities such as Swift and Fermi in the short term, and provide a means for GRB detection, localization, and characterization in the interim time before the next generation future gamma-ray mission flies, as well as space-qualify SiPMs and test technologies that may be used on the next generation gamma-ray probe or flagship. The ultimate configuration of BurstCube is to have a set of ~10 BurstCubes to provide all-sky coverage to GRBs for substantially lower cost than a full-scale mission.

  19. Design of a small robust DASH interferometer suitable for CubeSat observations of Thermospheric winds

    NASA Astrophysics Data System (ADS)

    Harlander, J.; Englert, C. R.

    2012-12-01

    The Doppler Asymmetric Spatial Heterodyne (DASH) concept has been proposed to measure upper atmospheric winds. The approach is identical to the concept of Spatial Heterodyne Spectroscopy (SHS) except one interferometer arm exhibits an additional optical path offset which optimizes the instrument for the measurement of atmospheric winds. A DASH interferometer is a field-widened Michelson that utilizes diffraction gratings instead of mirrors to measure an interferogram over a large path difference interval without moving parts. This feature enables the instrument to simultaneously monitor multiple atmospheric lines and calibration lines to track instrumental drifts. The DASH interferometer described in this paper is designed for satellite measurements of thermospheric winds using the upper atmospheric red line at λ=630.0 nm in a limb imaging geometry. The interferometer departs from previous designs in that the fringes are localized on a plane following the interferometer which eliminates the need for exit optics to re-image the interferogram onto the detector. Only one focusing optic is required to form an image of the limb through the interferometer onto the fringe localization plane. The resulting instrument assembly is smaller and lighter than previous designs making it suitable for deployment on a multi-U CubeSat platform. This paper will discuss the design of the real-fringe interferometer, its advantages and limitations when compared to earlier DASH designs and its possible implementation on a CubeSat.

  20. Mothership of Asteroid CubeSats - Enabling Low Cost Swarm Based Investigations of Small Bodies

    NASA Astrophysics Data System (ADS)

    DiCorcia, J. D.; Ernst, S. M.; Gump, D.; Owens, A.; Lewis, J. S.; Foulds, C.; Faber, D.

    2014-12-01

    Deep Space Industries is under contract to NASA to evaluate options for secondary spacecraft in support of the Asteroid Redirect Mission. One concept to enable broad participation by the scientific community is the Mothership of Asteroid CubeSats to deliver third-party experiments and sensors to a near Earth asteroid. The Mothership service includes delivery of nanosats built by a variety of non-DSI researchers, communications relay to Earth, and visuals of the asteroid surface and surrounding area. This service allows researchers to house their instruments in a low-cost nanosat body that does not require the high-performance propulsion or deep space communications capabilities that otherwise would be required for an asteroid mission. This enables organizations with relatively low operating budgets to closely examine an asteroid with highly specialized sensors of their own choosing. In addition, the Mothership and its deployed nanosats can offer a platform for instruments, that need to be distributed over multiple spacecraft. The Mothership would be designed to carry a variety of form factors, from chipsats to 1U to 8U CubeSats. The initial missions would begin as early as fourth quarter 2017 and continue through 2018-19. Special interest groups are being conducted for gathering input from the small body research community.

  1. Variability of Arctic sea ice thickness and volume from CryoSat-2.

    PubMed

    Kwok, R; Cunningham, G F

    2015-07-13

    We present our estimates of the thickness and volume of the Arctic Ocean ice cover from CryoSat-2 data acquired between October 2010 and May 2014. Average ice thickness and draft differences are within 0.16 m of measurements from other sources (moorings, submarine, electromagnetic sensors, IceBridge). The choice of parameters that affect the conversion of ice freeboard to thickness is discussed. Estimates between 2011 and 2013 suggest moderate decreases in volume followed by a notable increase of more than 2500 km(3) (or 0.34 m of thickness over the basin) in 2014, which could be attributed to not only a cooler summer in 2013 but also to large-scale ice convergence just west of the Canadian Arctic Archipelago due to wind-driven onshore drift. Variability of volume and thickness in the multiyear ice zone underscores the importance of dynamics in maintaining the thickness of the Arctic ice cover. Volume estimates are compared with those from ICESat as well as the trends in ice thickness derived from submarine ice draft between 1980 and 2004. The combined ICESat and CryoSat-2 record yields reduced trends in volume loss compared with the 5 year ICESat record, which was weighted by the record-setting ice extent after the summer of 2007.

  2. Three-dimensional mapping by CryoSat-2 of subglacial lake volume changes

    NASA Astrophysics Data System (ADS)

    McMillan, Malcolm; Corr, Hugh; Shepherd, Andrew; Ridout, Andrew; Laxon, Seymour; Cullen, Robert

    2013-08-01

    analyze data acquired by the CryoSat-2 interferometric radar altimeter and demonstrate its novel capability to track topographic features on the Antarctic Ice Sheet. We map the perimeter and depth of a 260 km2 surface depression above an Antarctic subglacial lake (SGL) and, in combination with Ice, Cloud and land Elevation Satellite laser altimetry, chart decadal changes in SGL volume. During 2007-2008, between 4.9 and 6.4 km3 of water drained from the SGL, and peak discharge exceeded 160 m3 s-1. The flood was twice as large as any previously recorded and equivalent to ~ 10% of the meltwater generated annually beneath the ice sheet. The ice surface has since uplifted at a rate of 5.6 ± 2.8 m yr-1. Our study demonstrates the ability of CryoSat-2 to provide detailed maps of ice sheet topography, its potential to accurately measure SGL drainage events, and the contribution it can make to understanding water flow beneath Antarctica.

  3. Ice sheet elevation change in West Antarctica from CryoSat interferometric altimetry

    NASA Astrophysics Data System (ADS)

    McMillan, M.; Shepherd, A.; Ridout, A.; Sundal, A.

    2013-12-01

    Two decades of radar altimetry have shown accelerating mass losses from the Amundsen Sea Sector of West Antarctica. The mass imbalance of this region, which dominates that of all Antarctica, manifests as sustained ice thinning focussed upon fast-flowing ice streams and their tributaries. Ongoing observations are required to determine whether rates of mass loss continue to increase and, more widely, to monitor the stability of this sector of the ice sheet. With the retirement of the ERS-2 satellite in 2011 and the loss of Envisat in 2012, CryoSat-2 offers the unique potential to extend the current altimetry record. In coastal regions of Antarctica the satellite operates in a novel Synthetic Aperture Radar interferometric (SARin) mode, which enables improved resolution and echo location. Here, we apply a repeat track algorithm to SARin mode data to derive ice sheet elevation, volume and mass changes during the period 2010-2013, focussing upon the Amundsen Sea Sector of West Antarctica. Binning elevation change measurements at 5 km resolution gives on average 40 observations per grid cell, illustrating the high sampling density offered by CryoSat-2. We find that, since the cessation of ERS and Envisat measurements, thinning continues to be most pronounced along the fast-flowing ice streams and tributaries, with rates of 4-8 m/yr near the grounding lines of the Pine Island, Thwaites and Smith Glaciers. We compare these new observations to previous measurements made by the ERS and Envisat satellites.

  4. HawkEye: CubeSat SeaWiFS update

    NASA Astrophysics Data System (ADS)

    Schueler, Carl; Holmes, Alan

    2016-09-01

    The SeaHawk 3U CubeSat program is funded by the Gordon and Betty Moore Foundation of San Francisco, and managed by John Morrison of the University of North Carolina-Wilmington (UNC-W). Cloudland Instruments is developing HawkEye for SeaHawk. HawkEye is a multispectral ocean color imager of SeaWiFS quality with 120 meter nadir resolution from an orbit altitude of 540 km to provide observation of sub-mesoscale variability for insights into poorly understood mixing dynamics. 120 meter imagery improves ability, relative to SeaWiFS 1km resolution, to monitor fjords, estuaries, coral reefs and other near-shore environments where anthropogenic stresses are often most acute and where there are considerable security and commercial interests. The optics, filters, and arrays comprise a cube 10 cm on a side to fit a 3U CubeSat manufactured by ClydeSpace of Glasgow Scotland, and provide a 350 km swath cross-track.

  5. Lake levels based on CryoSat-2 SAR radar altimetry

    NASA Astrophysics Data System (ADS)

    Nielsen, K.; Villadsen, H.; Stenseng, L.; Andersen, O. B.; Knudsen, P.

    2015-12-01

    CryoSat-2 is the satellite that carries a synthetic aperture radar (SAR) altimeter on-board. The SAR technology provides an along-track resolution of approximately 300 m. The higher resolution makes it possible to accurately monitor much smaller water bodies than previously. In this study, which is part of the FP7 project Land and Ocean take up from Sentinel-3 (LOTUS), we investigate the potential of SAR altimetry. To derive lake levels we use novel empirical threshold retrackers and the physical SAMOSA retracker. We consider lakes at various sizes and evaluate the CryoSat-2 derived lake levels in terms of along-track precision and agreement with in-situ data. We find that the precision of the along-track mean water level is a few cm, even for lakes with a surface area of just 9 km^2. The high precision makes it possible to detect water level variations below the decimeter level. To derive lake level time series we apply a state-space model with a robust handling of erroneous data. Instead of attempting to identify and remove the polluted observations we use a mixture distribution to describe the observation noise, which prevents the polluted observations from biasing our final reconstructed time series. These results demonstrate the promising possibilities of the upcoming Sentinel-3 mission, which potentially will be able to provide accurate time series for small lakes.

  6. DebriSat: The New Hypervelocity Impact Test for Satellite Breakup Fragment Characterization

    NASA Technical Reports Server (NTRS)

    Cowardin, Heather

    2015-01-01

    To replicate a hyper-velocity fragmentation event using modern-day spacecraft materials and construction techniques to better improve the existing DoD and NASA breakup models: DebriSat is intended to be representative of modern LEO satellites. Major design decisions were reviewed and approved by Aerospace subject matter experts from different disciplines. DebriSat includes 7 major subsystems. Attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. center dotA key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), supporting the development of the DoD and NASA satellite breakup models was conducted at AEDC in 1992. Breakup models based on SOCIT have supported many applications and matched on-orbit events reasonably well over the years.

  7. Comparison of Antarctic Basin Scale Mass Change from GRACE/GOCE and CryoSat-2

    NASA Astrophysics Data System (ADS)

    Bouman, J.; McMillan, M.; Ivins, E. R.; Blossfeld, M.; Fuchs, M.; Horwath, M.

    2014-12-01

    When data of the GRACE satellite gravity mission are combined with those of the satellite gravity gradiometer mission GOCE, it can be shown that trends in ice mass balance can be resolved at basin scale for the Amundsen Sea Sector in West Antarctica. We will extend our analysis to the complete Antarctic continent, paying special attention to unavoidable leakage effects between basins, and glacial isotactic adjustment and its uncertainty. In addition, it is known that the gravitational flattening coefficient is better determined from satellite laser ranging (SLR) than from GRACE. The GRACE C20 coefficients are therefore routinely replaced by those from SLR. We will show that an alternative SLR time series, using tracking data to more satellites, may give ice mass trend differences of 10 - 15 Gt/yr (in the order of 13% of the total signal) compared with the commonly applied SLR time series. With data of the CryoSat-2 radar altimeter mission Antarctic ice sheet elevation changes can be determined, which can be converted to mass changes. GRACE/GOCE and CryoSat-2 ice mass trends will be compared and the possible cause of differences will be discussed.

  8. The Application of the Logo Language for Future Astronomical PocketQubes and CubeSats

    NASA Astrophysics Data System (ADS)

    Jernigan, J. Garrett

    2014-06-01

    The PocketQube T-LogoQube was a successful test of a Logo based system for future astronomical CubeSats. The flight and ground software for T-LogoQube is based on the Logo programing language. This flight software is the first use of the Logo language for the control of any satellite. The T-LogoQube team is compised of ~50 people (professional mentors, faculty, and students). The T-LogoQube uLogo based flight system acheived the following goals:(1) Transmission of fours types of packet data with the RFM22B transceiver.(2) Ability to control T-LogoQube with a "one line uLogo program".(3) The uLogo VM includes a unigue time stamp for all data.(4) Past beacon packets are telemetered for a history of T-LogoQube.(5) Realtime flight analysis of the Magnetometer to measure spin rate on orbit(6) Ability to upload new uLogo code to extend the on orbit operation.(7) Single torque coil to point the T-LogoQube spin axis in any direction(8) Detection and ability to correct SEUsWe will present evolution of Logo for future CubeSats for space based astronomy projects.

  9. Geolocation and Pointing Accuracy Analysis for the WindSat Sensor

    NASA Technical Reports Server (NTRS)

    Meissner, Thomas; Wentz, Frank J.; Purdy, William E.; Gaiser, Peter W.; Poe, Gene; Uliana, Enzo A.

    2006-01-01

    Geolocation and pointing accuracy analyses of the WindSat flight data are presented. The two topics were intertwined in the flight data analysis and will be addressed together. WindSat has no unusual geolocation requirements relative to other sensors, but its beam pointing knowledge accuracy is especially critical to support accurate polarimetric radiometry. Pointing accuracy was improved and verified using geolocation analysis in conjunction with scan bias analysis. nvo methods were needed to properly identify and differentiate between data time tagging and pointing knowledge errors. Matchups comparing coastlines indicated in imagery data with their known geographic locations were used to identify geolocation errors. These coastline matchups showed possible pointing errors with ambiguities as to the true source of the errors. Scan bias analysis of U, the third Stokes parameter, and of vertical and horizontal polarizations provided measurement of pointing offsets resolving ambiguities in the coastline matchup analysis. Several geolocation and pointing bias sources were incfementally eliminated resulting in pointing knowledge and geolocation accuracy that met all design requirements.

  10. BioSentinel: Enabling CubeSat-Scale Biogical Research Beyond Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Sorgenfrei, Matt; Lewis, Brian S.

    2014-01-01

    The introduction of the Space Launch System will provide NASA with a new means of access to space beyond low Earth orbit (LEO), creating opportunities for scientific research in a range of spacecraft sizes. This presentation describes the preliminary design of the BioSentinel spacecraft, a CubeSat measuring 10cm x 20cm x 30cm, which has been manifested for launch on the maiden voyage of the Space Launch System in 2017. BioSentinel will provide the first direct experimental data from a biological study conducted beyond LEO in over forty years, which in turn will help to pave the way for future human exploration missions. The combination of an advanced biology payload with standard spacecraft bus components required for operation in deep space within a CubeSat form factor poses a unique challenge, and this paper will describe the early design trades under consideration. The baseline spacecraft design calls for the biology payload to occupy four cube-units of volume (denoted 4U), with all spacecraft bus components occupying the remaining 2U.

  11. The RAVAN CubeSat mission: Progress toward a new measurement of Earth outgoing radiation

    NASA Astrophysics Data System (ADS)

    Swartz, B. H.; Dyrud, L. P.; Lorentz, S. R.; Wu, D. L.; Wiscombe, W. J.; Papadakis, S.; Huang, P. M.; Smith, A.; Deglau, D.

    2014-12-01

    The Earth radiation imbalance (ERI) is the single most important quantity for predicting the course of climate change over the next century. The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat mission, funded by NASA's Earth Science Technology Office, will demonstrate an affordable, accurate radiometer that directly measures Earth-leaving fluxes of total and solar-reflected radiation. The objective of RAVAN is to demonstrate that a compact spaceborne radiometer that is absolutely accurate to NIST-traceable standards can be built for low cost. The key technologies that enable a radiometer with all these attributes are: a vertically aligned carbon nanotube (VACNT) absorber and a gallium fixed-point blackbody as a built-in calibration source. VACNTs are exceedingly black and spectrally flat, making them ideal radiometer absorbers. We present results from the fabrication and calibration of the RAVAN radiometer and plans for CubeSat hosting and launch. RAVAN will help enable the development of a constellation Earth radiation budget mission that can provide the measurements needed for superior predictions of future climate change.

  12. CryoSat Ice Processor: Known Processor Anomalies and Potential Future Product Evolutions

    NASA Astrophysics Data System (ADS)

    Mannan, R.; Webb, E.; Hall, A.; Bouffard, J.; Femenias, P.; Parrinello, T.; Bouffard, J.; Brockley, D.; Baker, S.; Scagliola, M.; Urien, S.

    2016-08-01

    Launched in 2010, CryoSat was designed to measure changes in polar sea ice thickness and ice sheet elevation. To reach this goal the CryoSat data products have to meet the highest performance standards and are subjected to a continual cycle of improvement achieved through upgrades to the Instrument Processing Facilities (IPFs). Following the switch to the Baseline-C Ice IPFs there are already planned evolutions for the next processing Baseline, based on recommendations from the Scientific Community, Expert Support Laboratory (ESL), Quality Control (QC) Centres and Validation campaigns. Some of the proposed evolutions, to be discussed with the scientific community, include the activation of freeboard computation in SARin mode, the potential operation of SARin mode over flat-to-slope transitory land ice areas, further tuning of the land ice retracker, the switch to NetCDF format and the resolution of anomalies arising in Baseline-C. This paper describes some of the anomalies known to affect Baseline-C in addition to potential evolutions that are planned and foreseen for Baseline-D.

  13. Adaptive fuzzy logic controller with direct action type structures for InnoSAT attitude control system

    NASA Astrophysics Data System (ADS)

    Bakri, F. A.; Mashor, M. Y.; Sharun, S. M.; Bibi Sarpinah, S. N.; Abu Bakar, Z.

    2016-10-01

    This study proposes an adaptive fuzzy controller for attitude control system (ACS) of Innovative Satellite (InnoSAT) based on direct action type structure. In order to study new methods used in satellite attitude control, this paper presents three structures of controllers: Fuzzy PI, Fuzzy PD and conventional Fuzzy PID. The objective of this work is to compare the time response and tracking performance among the three different structures of controllers. The parameters of controller were tuned on-line by adjustment mechanism, which was an approach similar to a PID error that could minimize errors between actual and model reference output. This paper also presents a Model References Adaptive Control (MRAC) as a control scheme to control time varying systems where the performance specifications were given in terms of the reference model. All the controllers were tested using InnoSAT system under some operating conditions such as disturbance, varying gain, measurement noise and time delay. In conclusion, among all considered DA-type structures, AFPID controller was observed as the best structure since it outperformed other controllers in most conditions.

  14. COVE, MARINA, and the Future of On-Board Processing (OBP) Platforms for CubeSat Science Missions

    NASA Astrophysics Data System (ADS)

    Pingree, P.; Bekker, D. L.; Bryk, M.; DeLucca, J.; Franklin, B.; Hancock, B.; Klesh, A. T.; Meehan, C.; Meshkaty, N.; Nichols, J.; Peay, C.; Rider, D. M.; Werne, T.; Wu, Y.

    2012-12-01

    The CubeSat On-board processing Validation Experiment (COVE), JPL's first CubeSat payload launched on October 28, 2011, features the Xilinx Virtex-5QV Single event Immune Reconfigurable FPGA (SIRF). The technology demonstration mission was to validate the SIRF device running an on-board processing (OBP) algorithm developed to reduce the data set by 2-orders of magnitude for the Multi-angle SpectroPolarimetric Imager (MSPI), an instrument under development at JPL (PI: D. Diner). COVE has a single data interface to the CubeSat flight computer that is used to transfer a static image taken from the CubeSat camera and store it to local memory where the FPGA then reads it to run the algorithm on it. In the next generation COVE design, called MARINA, developed for the GRIFEX CubeSat project, the OBP board is extended, using rigid-flex PCB technology, to provide an interface to a JPL-developed Read-Out Integrated Circuit (ROIC) hybridized to a detector developed by Raytheon. In this configuration the focal plane array (FPA) data can be streamed directly to the FPGA for data processing or for storage to local memory. The MARINA rigid-flex PCB design is integrated with a commercial camera lens to create a 1U instrument payload for integration with a CubeSat under development by the University of Michigan and planned for launch in 2014. In the GRIFEX technology demonstration, the limited on-board storage capacity is filled by high-rate FPA data in less than a second. The system is also limited by the CubeSat downlink data rate and several ground station passes are required to transmit this limited amount of data. While this system is sufficient to validate the ROIC technology on-orbit, the system cannot be operated in a way to perform continuous science observations due to the on-board storage and data downlink constraints. In order to advance the current platform to support sustained science observations, more on-board storage is needed. Radiation tolerant memory

  15. The Relationship between SAT® Scores and Retention to the Second Year: Replication with the 2010 SAT Validity Sample. Statistical Report 2013-1

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Patterson, Brian F.

    2013-01-01

    The College Board formed a research consortium with four-year colleges and universities to build a national higher education database with the primary goal of validating the revised SAT for use in college admission. A study by Mattern and Patterson (2009) examined the relationship between SAT scores and retention to the second year. The sample…

  16. SAT Scores, 2013-14: Wake County Public School System (WCPSS). Measuring Up. D&A Report No. 14.14

    ERIC Educational Resources Information Center

    Gilleland, Kevin; Muli, Juliana

    2014-01-01

    The SAT is a national college entrance examination offered by the College Board and consists of three parts: Mathematics, Critical Reading, and Writing. The top score for each part is 800, for a total possible score of 2400. Colleges use SAT scores, in conjunction with other tools, to measure students' potential for success at the postsecondary…

  17. Phase Transition in Computing Cost of Overconstrained NP-Complete 3-SAT Problems

    NASA Astrophysics Data System (ADS)

    Woodson, Adam; O'Donnell, Thomas; Maniloff, Peter

    2002-03-01

    Many intractable, NP-Complete problems such as Traveling Salesmen (TSP) and 3-Satisfiability (3-Sat) which arise in hundreds of computer science, industrial and commercial applications, are now known to exhibit phase transitions in computational cost. While these problems appear to not have any structure which would make them amenable to attack with quantum computing, their critical behavior may allow physical insights derived from statistical mechanics and critical theory to shed light on these computationally ``hardest" of problems. While computational theory indicates that ``the intractability of the NP-Complete class resides solely in the exponential growth of the possible solutions" with the number of variables, n, the present work instead investigates the complex patterns of ``overlap" amongst 3-SAT clauses (their combined effects) when n-tuples of these act in succession to reduce the space of valid solutions. An exhaustive-search algorithm was used to eliminate `bad' states from amongst the `good' states residing within the spaces of all 2^n--possible solutions of randomly generated 3-Sat problems. No backtracking nor optimization heuristics were employed, nor was problem structure exploited (i.e., phtypical cases were generated), and the (k=3)-Sat propositional logic problems generated were in standard, conjunctive normal form (CNF). Each problem had an effectively infinite number of clauses, m (i.e., with r = m/n >= 10), to insure every problem would not be satisfiable (i.e. that each would fail), and duplicate clauses were not permitted. This process was repeated for each of several low values of n (i.e., 4 <= n <= 20). The entire history of solution-states elimination as successive clauses were applied was archived until, in each instance, sufficient clauses were applied to kill all possible solutions . An asymmetric, sigmoid-shaped phase transition is observed in Fg = F_g(m'/n), the fraction of the original 2^n ``good" solutions remaining valid as a

  18. CryoSat Plus for Oceans - analysis of the state-of-the-art

    NASA Astrophysics Data System (ADS)

    Naeije, Marc; Gommenginger, Christine; Moreau, Thomas; Cotton, David; Benveniste, Jerome; Dinardo Dinardo, Salvatore

    2013-04-01

    The CryoSat Plus for Oceans (CP4O) project is an ESA initiative carried out by a European wide consortium of altimetry experts. It aims to build a sound scientific basis for new scientific and operational applications of data coming from CryoSat-2 over the open ocean, polar ocean, coastal seas and for seafloor mapping. It also generates and evaluates new methods and products that will enable the full exploitation of the capabilities of the CryoSat-2 SIRAL altimeter, and extend their application beyond the initial mission objectives. It therefore also acts as a preparation for the upcoming Sentinel and Jason SAR enabled altimetry missions. In this paper we address the review of the CryoSat state-of-the-art, relevant current initiatives, algorithms, models and Earth Observation based products and datasets that are relevant in the Cryosat+ ocean theme. Compared to conventional (pulse-limited) altimeter missions, Cryosat-2 is not a dedicated platform for ocean research: typically the microwave radiometer (MWR) for wet tropospheric corrections is lacking, as is the direct measurement of the first order ionospheric effect by means of a dual-frequency altimeter. Also the orbit of Cryosat-2 has a rather long repetition period, unsuited for collinear tracks analyses. These three particular features have been studied already in the HERACLES project on the eve of the first CryoSat launch. We revisit the outcome of this study, update to current understanding and perception, and ultimately develop what was, is and will be proposed in these problem areas. Clearly, we question the standard ionosphere corrections, the wet troposphere corrections and the accuracy of the mean sea surface (MSS) underlying the accuracy of derived sea level anomalies. In addition, Cryosat-2 provides the first innovative altimeter with SAR and SARIn modes. This raises the direct problem of "how to process these data", simply because this has not been done before. Compared to pulse-limited altimetry it

  19. CryoSat-2 Estimates of Sea Ice Freeboard in the Greenland Sea of Arctic

    NASA Astrophysics Data System (ADS)

    Zhang, S.

    2015-12-01

    Arctic region is one of the most important parts that contribute to the global climate system. As an important climatic indicator, sea ice has also undergone dramatic changes. Due to the limitations of poor geographical conditions and a lack of in-situ observations, knowledge about Arctic sea ice has not been explored well for a long time, furthermore it is especial difficult to get a high quality of Arctic Sea ice thickness information.Equipped with a Ku-band SIRAL, CryoSat-2 has been launched in 2010 as an important European Space Agency Earth Explorer Opportunity mission. CryoSat-2 has the advantage of measuring the thickness of polar sea ice and monitoring changes in the ice sheets that blanket Greenland and Antarctica with high precision. In this paper, the CryoSat-2/SIRAL radar altimeter data were used to retrieve the sea ice thickness in the Greenland Sea, Arctic, validated with the Ice, Cloud, and Land Elevation (ICESat) laser altimeter measurements from National Aeronautics and Space Administration (NASA) and Beaufort Gyre Experiment Program (BGEP) Upward Looking Sonar (ULS) measurements. Results show that the sea ice freeboard in Greenland Sea has a remarkable seasonal variation and presents an evident regional characteristics. As it show below, during the frozen season in autumn and winter the sea ice freeboard concentrated in around 0.23m , the average freeboard in Greenland Sea in June decreased to around 0.18m, the minimum freeboard 0.12m appeared in September. In the Western Greenland Sea near the Greenland and the Fram Strait with higher-latitude where multi-year ice occupy most has a larger freeboard around 0.3m in winter. In the south-eastern Greenland Sea with lower-latitude and shallow sea water, the freeboard composed by first-year ice concentrated in around 0.1m in winter. At the same time, the sea ice area also had seasonal variations, its maximum was in January and March, and minimum was in September.

  20. Winter QPF Sensitivities to Snow Parameterizations and Comparisons to NASA CloudSat Observations

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew; Haynes, John M.; Jedlovec, Gary J.; Lapenta, William M.

    2009-01-01

    Steady increases in computing power have allowed for numerical weather prediction models to be initialized and run at high spatial resolution, permitting a transition from larger scale parameterizations of the effects of clouds and precipitation to the simulation of specific microphysical processes and hydrometeor size distributions. Although still relatively coarse in comparison to true cloud resolving models, these high resolution forecasts (on the order of 4 km or less) have demonstrated value in the prediction of severe storm mode and evolution and are being explored for use in winter weather events . Several single-moment bulk water microphysics schemes are available within the latest release of the Weather Research and Forecast (WRF) model suite, including the NASA Goddard Cumulus Ensemble, which incorporate some assumptions in the size distribution of a small number of hydrometeor classes in order to predict their evolution, advection and precipitation within the forecast domain. Although many of these schemes produce similar forecasts of events on the synoptic scale, there are often significant details regarding precipitation and cloud cover, as well as the distribution of water mass among the constituent hydrometeor classes. Unfortunately, validating data for cloud resolving model simulations are sparse. Field campaigns require in-cloud measurements of hydrometeors from aircraft in coordination with extensive and coincident ground based measurements. Radar remote sensing is utilized to detect the spatial coverage and structure of precipitation. Here, two radar systems characterize the structure of winter precipitation for comparison to equivalent features within a forecast model: a 3 GHz, Weather Surveillance Radar-1988 Doppler (WSR-88D) based in Omaha, Nebraska, and the 94 GHz NASA CloudSat Cloud Profiling Radar, a spaceborne instrument and member of the afternoon or "A-Train" of polar orbiting satellites tasked with cataloguing global cloud