WorldWideScience

Sample records for satellites europa ganymede

  1. Stability of orbits around planetary satellites considering a disturbing body in an elliptical orbit: Applications to Europa and Ganymede

    Science.gov (United States)

    Cardoso dos Santos, Josué; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho

    Europa and Ganymede are two of the four Jupiter’s moons which compose the Galilean satellite. These ones are planetary satellites of greater interest at the present moment among the scientific community. There are some missions being planned to visit them and and the Jovian system. One of them is the cooperation between NASA and ESA for the Europa Jupiter System Mission (EJSM). In this mission are planned the insertion of the spacecrafts JEO (Jupiter Europa Orbiter) and JGO (Jupiter Ganymede Orbiter) into Europa and Ganymede’s orbit. Thus, there is a great necessity for having a better comprehension of the dynamics of the orbits around this planetary satellite. This comprehension is essential for the success of this type of mission. In this context, this work aims to perform a search for low-altitude orbits around these planetary satellites. An emphasis is given in polar orbits. These orbits can be useful in the planning of aerospace activities to be conducted around this planetary satellite, with respect to the stability of orbits of artificial satellites. The study considers orbits of an artificial satellite around Europa and Ganymede under the influence of the third-body perturbation (the gravitational attraction of Jupiter) and the polygenic perturbations. These last ones occur due to forces such as the non-uniform distribution of mass (J2 and J3) of the main (central) body. A simplified dynamic model for polygenic perturbations is used. A new model for the third-body disturbance is presented considering it in an elliptical orbit. The Lagrange planetary equations, which compose a system of nonlinear differential equations, are used to describe the orbital motion of the artificial satellite around Ganymede. The equations showed here are developed in closed form to avoid expansions in inclination and eccentricity.

  2. The gravity fields of Ganymede, Callisto and Europa: how well can JUICE do?

    Science.gov (United States)

    Parisi, Marzia; Iess, Luciano; Finocchiaro, Stefano

    2014-05-01

    With 20 flybys of Callisto, 2 of Europa and an extended orbital phase around Ganymede, ESA's JUICE mission offers an excellent opportunity to investigate the interiors of the three Galilean satellites. All of these moons can host an internal ocean, but the evidence is compelling only for Europa, where Galileo's measurements of the induced magnetic field are not marred by an intrinsic field as for Ganymede. However, both Europa's and Ganymede's appear to be differentiated (Showman and Malhotra, 1999), and probably hosting a subsurface liquid water ocean underneath the icy surface (Khurana et al., 1998; Kivelson et al., 2002). But even for Callisto, which appears as an undifferentiated body of ice and rock (Showman and Malhotra, 1999), a global or partial subsurface ocean cannot be ruled out (Khurana et al., 1998). The determination of the interior structure of the Galilean satellites, one of the main goal of the JUICE mission, can be accomplished by a combination of gravity, altimetric and magnetic measurements. Gravity measurements are addressed by the 3GM (Geodesy and Geophysics of Jupiter and the Galilean Moons) by means of highly accurate Doppler tracking of the spacecraft from ground antennas. Precise range rate measurements are enabled by a dedicated Ka-band (32-34 GHz) transponder, heritage from the Juno and BepiColombo missions. The expected range rate accuracies are around 0.01 mm/s at 60 s integration time, at nearly all solar elongation angles. A complete cancellation of the interplanetary plasma noise is indeed possible by operating simultaneously the links at X and Ka band. The current mission profile envisages two, low altitude, orbital phases around Ganymede: a circular polar, orbit at an altitude of 500 km for the first 102 days, and circular polar orbit at an altitude of 200 km for the last 30 days. The low altitude will permit the determination of Ganymede's gravity field with a relative accuracy of about 10^-5 for both J2 and C22. The 18 tidal

  3. Can a future mission detect a habitable ecosystem on Europa, or Ganymede?

    Science.gov (United States)

    Chela Flores, Julian

    2010-05-01

    orbital probes in the future exploration of Jupiter's System (Gowen et al., 2009). There are alternative views on the effect of space weather on the radiation-induced S-cycles produced on the surficial molecules; but S is common to both interpretations (Carlson et al., 1999; McCord et al., 1999). The largest known S-fractionations are due to microbial reduction, and not to thermochemical processes. Besides, sulphate abiotic reductions are generally not as large as the biogenic ones (Kiyosu and Krouse, 1990). From experience with a natural population, this type of biota is able to fractionate efficiently the S-isotopes up to delta 34S of -70 per mil (Wortmann et al., 2001). Dissimilatory sulphate reducers are ubiquitous on Earth, producing the largest fractionations in the sulphur stable isotopes. These microbes are widely distributed in terrestrial anoxic environments.Consequently, sulphate reducers are the most evident candidates for the microorganisms populating a habitable Europan ecosystem. Microbial fractionation of stable S-isotopes argue in favour of penetrators for surveying the surface of not only Europa, but also of Ganymede, where surficial sulphur has been detected (McCord et al., 1997). The Europa-Jupiter System Mission (EJSM) intends to explore in the 2020s both of these satellites (Grasset et al., 2009). According to our hypothesis we predict that penetrators (supplied with mass spectrometry) should yield different results for fractionated sulphur. The icy patches on Europa should give substantial depletions of delta 34S, while measurements on Ganymede should give significantly lower values for the depletion of delta 34S. (Since the largest of the Galilean satellites lacks an ocean-core interface, according to our hypothesis it would not support life.) These diverging results—a large minus delta 34S for the Europan sulphur patches, and a small minus delta 34S for the Ganymede surficial sulphur—would provide a clear test for the hypothesis that a

  4. Satellites

    International Nuclear Information System (INIS)

    Burns, J.A.; Matthews, M.S.

    1986-01-01

    The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system

  5. The Longevity of Water Ice on Ganymedes and Europas around Migrated Giant Planets

    International Nuclear Information System (INIS)

    Lehmer, Owen R.; Catling, David C.; Zahnle, Kevin J.

    2017-01-01

    The gas giant planets in the Solar System have a retinue of icy moons, and we expect giant exoplanets to have similar satellite systems. If a Jupiter-like planet were to migrate toward its parent star the icy moons orbiting it would evaporate, creating atmospheres and possible habitable surface oceans. Here, we examine how long the surface ice and possible oceans would last before being hydrodynamically lost to space. The hydrodynamic loss rate from the moons is determined, in large part, by the stellar flux available for absorption, which increases as the giant planet and icy moons migrate closer to the star. At some planet–star distance the stellar flux incident on the icy moons becomes so great that they enter a runaway greenhouse state. This runaway greenhouse state rapidly transfers all available surface water to the atmosphere as vapor, where it is easily lost from the small moons. However, for icy moons of Ganymede’s size around a Sun-like star we found that surface water (either ice or liquid) can persist indefinitely outside the runaway greenhouse orbital distance. In contrast, the surface water on smaller moons of Europa’s size will only persist on timescales greater than 1 Gyr at distances ranging 1.49–0.74 au around a Sun-like star for Bond albedos of 0.2 and 0.8, where the lower albedo becomes relevant if ice melts. Consequently, small moons can lose their icy shells, which would create a torus of H atoms around their host planet that might be detectable in future observations.

  6. The Longevity of Water Ice on Ganymedes and Europas around Migrated Giant Planets

    Energy Technology Data Exchange (ETDEWEB)

    Lehmer, Owen R.; Catling, David C. [Dept. of Earth and Space Sciences/Astrobiology Program, University of Washington, Seattle, WA (United States); Zahnle, Kevin J., E-mail: olehmer@gmail.com [NASA Ames Research Center, Moffett Field, CA (United States)

    2017-04-10

    The gas giant planets in the Solar System have a retinue of icy moons, and we expect giant exoplanets to have similar satellite systems. If a Jupiter-like planet were to migrate toward its parent star the icy moons orbiting it would evaporate, creating atmospheres and possible habitable surface oceans. Here, we examine how long the surface ice and possible oceans would last before being hydrodynamically lost to space. The hydrodynamic loss rate from the moons is determined, in large part, by the stellar flux available for absorption, which increases as the giant planet and icy moons migrate closer to the star. At some planet–star distance the stellar flux incident on the icy moons becomes so great that they enter a runaway greenhouse state. This runaway greenhouse state rapidly transfers all available surface water to the atmosphere as vapor, where it is easily lost from the small moons. However, for icy moons of Ganymede’s size around a Sun-like star we found that surface water (either ice or liquid) can persist indefinitely outside the runaway greenhouse orbital distance. In contrast, the surface water on smaller moons of Europa’s size will only persist on timescales greater than 1 Gyr at distances ranging 1.49–0.74 au around a Sun-like star for Bond albedos of 0.2 and 0.8, where the lower albedo becomes relevant if ice melts. Consequently, small moons can lose their icy shells, which would create a torus of H atoms around their host planet that might be detectable in future observations.

  7. Europa

    International Nuclear Information System (INIS)

    Malin, M.C.; Pieri, D.C.

    1986-01-01

    Europa, the second major satellite outward from Jupiter, is a lunar-sized object in synchronous rotation about that planet. Its high albedo and spectral characteristics indicate the presence of surface water ice and/or frost. Its density suggests a substantial silicate component of at least 85 percent by volume. A limited variety of landforms is seen in Voyager images, most likely because of poor spatial resolution of these data. The absence of numerous impact craters is interpreted as indicating a youthful surface and /or surface regenerating processes. A planet-wide lineament system has been interpreted to result from tectonic stresses induced by evolution of Europa's orbit and interior. Present data do not permit unambiguous tests of such interpretations. Greater insight may come from analytical or numerical models and future spacecraft observations

  8. Europa

    DEFF Research Database (Denmark)

    Hansen, Ole Erik

    2000-01-01

    Artiklen behandler, hvordan Europa blev centrum for den globale økonomiske udvikling, og hvilken rolle nationalstaterne har spillet for Europas udvikling. Derudover behandles det, hvordan den europæiske integrationsproces kan ses som et forsøg på at genskabe Europas centrale politiske og økonomis...

  9. Stable low-altitude orbits around Ganymede considering a disturbing body in a circular orbit

    Science.gov (United States)

    Cardoso dos Santos, J.; Carvalho, J. P. S.; Vilhena de Moraes, R.

    2014-10-01

    Some missions are being planned to visit Ganymede like the Europa Jupiter System Mission that is a cooperation between NASA and ESA to insert the spacecraft JGO (Jupiter Ganymede Orbiter) into Ganymedes orbit. This comprehension of the dynamics of these orbits around this planetary satellite is essential for the success of this type of mission. Thus, this work aims to perform a search for low-altitude orbits around Ganymede. An emphasis is given in polar orbits and it can be useful in the planning of space missions to be conducted around, with respect to the stability of orbits of artificial satellites. The study considers orbits of artificial satellites around Ganymede under the influence of the third-body (Jupiter's gravitational attraction) and the polygenic perturbations like those due to non-uniform distribution of mass (J_2 and J_3) of the main body. A simplified dynamic model for these perturbations is used. The Lagrange planetary equations are used to describe the orbital motion of the artificial satellite. The equations of motion are developed in closed form to avoid expansions in eccentricity and inclination. The results show the argument of pericenter circulating. However, low-altitude (100 and 150 km) polar orbits are stable. Another orbital elements behaved variating with small amplitudes. Thus, such orbits are convenient to be applied to future space missions to Ganymede. Acknowledgments: FAPESP (processes n° 2011/05671-5, 2012/12539-9 and 2012/21023-6).

  10. Studying the Formation, Evolution, and Habitability of the Galilean Satellites

    Science.gov (United States)

    McGrath, M.; Waite, J. H. Jr.; Brockwell, T.; McKinnon, W.; Wyrick, D.; Mousis, O.; Magee, B.

    2013-01-01

    Highly sensitive, high-mass resolution mass spectrometry is an important in situ tool for the study of solar system bodies. In this talk we detail the science objectives, develop the rationale for the measurement requirements, and describe potential instrument/mission methodologies for studying the formation, evolution, and habitability of the Galilean satellites. We emphasize our studies of Ganymede and Europa as described in our instrument proposals for the recently selected JUICE mission and the proposed Europa Clipper mission.

  11. Dusk/dawn atmospheric asymmetries on tidally-locked satellites: O2 at Europa

    Science.gov (United States)

    Oza, Apurva V.; Johnson, Robert E.; Leblanc, François

    2018-05-01

    We use a simple analytic model to examine the effect of the atmospheric source properties on the spatial distribution of a volatile in a surface-bounded atmosphere on a satellite that is tidally-locked to its planet. Spatial asymmetries in the O2 exosphere of Europa observed using the Hubble Space Telescope appear to reveal on average a dusk enhancement in the near-surface ultraviolet auroral emissions. Since the hop distances in these ballistic atmospheres are small, we use a 1-D mass conservation equation to estimate the latitudinally-averaged column densities produced by suggested O2 sources. Although spatial asymmetries in the plasma flow and in the surface properties certainly affect the spatial distribution of the near-surface aurora, the dusk enhancements at Europa can be understood using a relatively simple thermally-dependent source. Such a source is consistent with the fact that radiolytically produced O2 permeates their porous regoliths and is not so sensitive to the local production rate from ice. The size of the shift towards dusk is determined by the ratio of the rotation rate and atmospheric loss rate. A thermally-dependent source emanating from a large reservoir of O2 permeating Europa's icy regolith is consistent with the suggestion that its subsurface ocean might be oxidized by subduction of such radiolytic products.

  12. The Ultraviolet Albedo of Ganymede

    Science.gov (United States)

    McGrath, Melissa; Hendrix, A.

    2013-10-01

    A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede’s stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede’s UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values. References Carlson, R. and 39 co-authors, Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: Results from Galileo’s initial orbit, Science, 274, 385-388, 1996. Eviatar, A., D. F. Strobel, B. C. Wolven, P. D. Feldman, M. A. McGrath, and D. J. Williams, Excitation of the Ganymede ultraviolet aurora, Astrophys. J, 555, 1013-1019, 2001. Feldman, P. D., M. A. McGrath, D. F. Strobel, H. W. Moos, K. D. Retherford, and B. C. Wolven, HST/STIS imaging of ultraviolet aurora on Ganymede, Astrophys. J, 535, 1085-1090, 2000. McGrath M. A., Lellouch E., Strobel D. F., Feldman P. D., Johnson R. E., Satellite Atmospheres, Chapter 19 in Jupiter: The Planet, Satellites and Magnetosphere, ed. F. Bagenal, T. Dowling, W. McKinnon, Cambridge University Press, 2004. McGrath M. A., Jia, Xianzhe; Retherford, Kurt; Feldman, Paul D.; Strobel, Darrell F.; Saur, Joachim, Aurora on Ganymede, J. Geophys. Res., doi: 10.1002/jgra.50122, 2013. Saur, J., S. Duling, S., L. Roth, P. D. Feldman, D. F. Strobel, K. D. Retherford, M. A. McGrath, A. Wennmacher, American Geophysical Union, Fall Meeting

  13. Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa

    Science.gov (United States)

    Prieto-Ballesteros, O.; Kargel, J.S.

    2005-01-01

    The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are "painted" into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in some areas, but in other places there are other minerals involved. Non-ice minerals are visually recognized by their low albedo and reddish color either when first emplaced or, more likely, after alteration by Europan weathering processes, especially sublimation and alteration by ionizing radiation. While red chromophoric material could be due to endogenic production of solid sulfur allotropes or other compounds, most likely the red substance is an impurity produced by radiation alteration of hydrated sulfate salts or sulphuric acid of mainly internal origin. If the non-ice red materials or their precursors have a source in the satellite interior, and if they are not merely trace contaminants, then they can play an important role in the evolution of the icy crust, including structural differentiation and the internal dynamics. Here we assume that these substances are major components of Europa's cryo/hydrosphere, as some models have predicted they should be. If this is an accurate assumption, then these substances should not be neglected in physical, chemical, and biological models of Europa, even if major uncertainties remain as to the exact identity, abundance, and distribution of the non-ice materials. The physical chemical properties of the ice-associated materials will contribute to the physical state of the crust today and in the geological past. In order to model the influence of them on the thermal state and the geology, we have determined the thermal properties of the hydrated salts. Our new lab data reveal very low thermal conductivities for hydrated salts compared to water ice. Lower conductivities of salty ice would

  14. Review of Exchange Processes on Ganymede in View of Its Planetary Protection Categorisation

    Science.gov (United States)

    Grasset, O.; Bunce, E. J.; Coustenis, A.; Dougherty, M. K.; Erd, C.; Hussmann, H.; Jaumann, R.; Prieto-Ballesteros, O.

    2013-09-01

    The outer planet satellites are a rich and diverse set of planetary bodies, with great relevance to astrobiological studies, satisfying a number or all of the prerequisites for habitability. Some of them show evidence for organic chemistry in their atmospheres, surfaces or interiors. Many of the satellites, including the smallest, thus contain organic material. In addition, the largest satellites are believed to hide global-scale oceans within. During the earlier Galileo mission, strong evidence for the presence of an internal ocean was obtained at Europa. Since then, the evidence has accumulated for such sub-surface liquid water oceans to exist not only on Europa but also on the two other icy Galilean satellites, Ganymede, and Callisto. Our current understanding of the deep habitats has raised the question of the necessary measures regarding planetary protection procedures for future missions. Many of the science questions relate to the prospects for life and habitability in the Solar System. As a consequence, some of the future mission opportunities and their potential encounters with habitable zones raise serious questions about biological or organic forward contamination that may be caused by these missions. In the 2012 NAP report[1], it is suggested that Ganymede is of significant interest relative to the process of chemical evolution and the origin of life, but that there is only a remote chance that contamination by a spacecraft could compromise future investigations. Still, further studies were desired to assess the possibility, the timescale, and the mechanisms of transport of any organism from the surface to the liquid layer. This is the purpose of this work.

  15. Ganymede and Callisto

    Science.gov (United States)

    Squyres, S. W.

    1983-01-01

    It is noted that even though the two moons have very similar masses and densities and formed in the same part of the solar system, Ganymede underwent widespread geologic activity whereas Callisto appears to have remained dormant. It is believed that the reason for this may involve several factors. Callisto has undoubtedly experienced at least some internal differentiation; if, however, the differentiation was less complete than for Ganymede or if it took place more slowly, some expansion could have occurred without the crust ever having been fractured. All the major heat sources in these moons produce more heat in Ganymede than in Callisto. Since Ganymede is more massive and dense than Callisto, its silicate content is significantly higher. Because the major radioactive elements are present only in the silicates, radiogenic heating is greater for Ganymede than for Callisto (by an estimated 60%) Ganymede has also undergone significantly more accretional heating than Callisto, not only because of its greater mass and stronger gravitational attraction, which lead to higher impact velocities, but also because it lies closer to Jupiter. The strong gravitational attraction of Jupiter greatly increases the impact velocities of any debris coming from outside the Jupiter system.

  16. The rotation of Titan and Ganymede

    Science.gov (United States)

    Van Hoolst, Tim; Coyette, Alexis; Baland, Rose-Marie; Trinh, Antony

    2016-10-01

    The rotation rates of Titan and Ganymede, the largest satellites of Saturn and Jupiter, are on average equal to their orbital mean motion. Here we discuss small deviations from the average rotation for both satellites and evaluate the polar motion of Titan induced by its surface fluid layers. We examine different causes at various time scales and assess possible consequences and the potential of using librations and polar motion as probes of the interior structure of the satellites.The rotation rate of Titan and Ganymede cannot be constant on the orbital time scale as a result of the gravitational torque of the central planet acting on the satellites. Titan is moreover expected to show significant polar motion and additional variations in the rotation rate due to angular momentum exchange with the atmosphere, mainly at seasonal periods. Observational evidence for deviations from the synchronous state has been reported several times for Titan but is unfortunately inconclusive. The measurements of the rotation variations are based on determinations of the shift in position of Cassini radar images taken during different flybys. The ESA JUICE (JUpiter ICy moons Explorer) mission will measure the rotation variations of Ganymede during its orbital phase around the satellite starting in 2032.We report on different theoretical aspects of the librations and polar motion. We consider the influence of the rheology of the ice shell and take into account Cassini measurements of the external gravitational field and of the topography of Titan and similar Galileo data about Ganymede. We also evaluate the librations and polar motion induced by Titan's hydrocarbon seas and use the most recent results of Titan's atmosphere dynamics. We finally evaluate the potential of rotation variations to constrain the satellite's interior structure, in particular its ice shell and ocean.

  17. Galileo's first images of Jupiter and the Galilean satellites

    Science.gov (United States)

    Belton, M.J.S.; Head, J. W.; Ingersoll, A.P.; Greeley, R.; McEwen, A.S.; Klaasen, K.P.; Senske, D.; Pappalardo, R.; Collins, G.; Vasavada, A.R.; Sullivan, R.; Simonelli, D.; Geissler, P.; Carr, M.H.; Davies, M.E.; Veverka, J.; Gierasch, P.J.; Banfield, D.; Bell, M.; Chapman, C.R.; Anger, C.; Greenberg, R.; Neukum, G.; Pilcher, C.B.; Beebe, R.F.; Burns, J.A.; Fanale, F.; Ip, W.; Johnson, T.V.; Morrison, D.; Moore, J.; Orton, G.S.; Thomas, P.; West, R.A.

    1996-01-01

    The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on lo. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution.

  18. The impact of ice I rheology on interior models of Ganymede: The elastic vs. the visco-elastic case

    Science.gov (United States)

    Steinbrügge, Gregor; Hussmann, Hauke; Sohl, Frank; Oberst, Jürgen

    2015-04-01

    Many investigations on key processes of icy satellites are driven by the rheological behavior of planetary ices. Future missions to Jupiter's icy moons (e.g. JUICE / Europa clipper) aimed at constraining the thickness of the outer ice shell using radio science and/or laser altimetry will have to address this problem. We investigate for the case of Ganymede under which conditions the ice I viscosity could be constrained by measuring the phase-lag of the tidal response using laser altimetry. In the absence of seismic data, interior structure models are constrained by the satellite's mean density and mean moment-of-inertia factor. One key observable to reduce the ambiguity of the corresponding structural models is the measurement of the dynamic response of the satellite's outer ice shells to tidal forces exerted by Jupiter and characterized by the body tide surface Love numbers h2 and k2. The Love number k2 measures the variation of the gravitational potential due to tidally induced internal redistribution of mass and can be inferred from radio science experiments. The Love number h2 is a measure for the tide-induced radial displacement of the satellite's surface. It is an advantage that Ganymede's surface displacement Love number h2 can be expected to be measured with a high accuracy using laser altimetry (Steinbrügge et al., 2014). However, the determination of the resulting ice thickness further depends on the possible existence of a liquid subsurface water ocean and on the tidally effective rheology of the outer ice shell (Moore and Schubert, 2003). Here, we distinguish between an elastic, visco-elastic or even fluid behavior in the sense of the Maxwell model and alternative rheological models. In the case of Ganymede the fluid case would imply high ice temperatures which are at odds with thermal equilibrium models calculated by Spohn and Schubert (2003). However the visco-elastic case is still possible. Laboratory measurements of ice I (e.g. Sotin et al., 1998

  19. Energetic Ion and Electron Irradiation of the Icy Galilean Satellites

    Science.gov (United States)

    Cooper, John F.; Johnson, Robert E.; Mauk, Barry H.; Garrett, Henry B.; Gehrels, Neil

    2001-01-01

    Galileo Orbiter measurements of energetic ions (20 keV to 100 MeV) and electrons (20-700 keV) in Jupiter's magnetosphere are used, in conjunction with the JPL electron model (less than 40 MeV), to compute irradiation effects in the surface layers of Europa, Ganymede, and Callisto. Significant elemental modifications are produced on unshielded surfaces to approximately centimeter depths in times of less than or equal to 10(exp 6) years, whereas micrometer depths on Europa are fully processed in approximately 10 years. Most observations of surface composition are limited to optical depths of approximately 1 mm, which are indirect contact with the space environment. Incident flux modeling includes Stormer deflection by the Ganymede dipole magnetic field, likely variable over that satellite's irradiation history. Delivered energy flux of approximately 8 x 10(exp 10) keV/square cm-s at Europa is comparable to total internal heat flux in the same units from tidal and radiogenic sources, while exceeding that for solar UV energies (greater than 6 eV) relevant to ice chemistry. Particle energy fluxes to Ganymede's equator and Callisto are similar at approximately 2-3 x 10(exp 8) keV/square cm-s with 5 x 10(exp 9) at Ganymede's polar cap, the latter being comparable to radiogenic energy input. Rates of change in optical reflectance and molecular composition on Europa, and on Ganymede's polar cap, are strongly driven by energy from irradiation, even in relatively young regions. Irradiation of nonice materials can produce SO2 and CO2, detected on Callisto and Europa, and simple to complex hydrocarbons. Iogenic neutral atoms and meteoroids deliver negligible energy approximately 10(exp 4-5) keV/square cm-s but impacts of the latter are important for burial or removal of irradiation products. Downward transport of radiation produced oxidants and hydrocarbons could deliver significant chemical energy into the satellite interiors for astrobiological evolution in putative sub

  20. Signature of Europa's Ocean Density on Gravity Data

    Science.gov (United States)

    Castillo, J. C.; Rambaux, N.

    2015-12-01

    Observations by the Galileo mission at Europa and Cassini-Huygens mission at Europa, Ganymede, Callisto, Enceladus, and Titan have found deep oceans at these objects with evidence for the presence of salts. Salt compounds are the products of aqueous alteration of the rock phase under hydrothermal conditions and have been predicted theoretically for these objects per analogy with carbonaceous chondrite parent bodies. Evidence for salt enrichment comes from magnetometer measurements (Galilean satellites), direct detection in the case of Enceladus, and inversion of the gravity data obtained at Titan. While there is direct detection for the presence of chlorides in icy grains ejected from Enceladus, the chemistry of the oceans detected so far, or even their densities, remain mostly unconstrained. However the increased ocean density impacts the interpretation of the tidal Love number k2and this may introduce confusion in the inference of the icy shell thickness from that parameter. We will present estimates of k2for a range of assumptions on Europa's hydrospheric structure that build on geophysical observations obtained by the Galileo mission combined with new models of Europa's interior. These models keep track of the compositions of the hydrated core and oceanic composition in a self-consistent manner. We will also estimate the electrical conductivity corresponding to the modeled oceanic composition. Finally we will explore how combining electromagnetic, topographic, and gravity data can decouple the signatures of the shell thickness and ocean composition on these geophysical observations. Acknowledgement: This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Government sponsorship acknowledged.

  1. Global Europa

    DEFF Research Database (Denmark)

    Manners, Ian

    2010-01-01

    at the mythology of ‘global Europa' - the EU in the world. It concludes with a reflection on the way in which the many diverse myths of global Europa compete for daily attention, whether as lore, ideology, or pleasure. In this respect the mythology of global Europa is part of our everyday existence, part of the EU...

  2. Dome craters on Ganymede

    International Nuclear Information System (INIS)

    Moore, J.M.; Malin, M.C.

    1987-01-01

    Voyager observations reveal impact craters on Ganymede that are characterized by the presence of broad, high albedo, topographic domes situated within a central pit. Fifty-seven craters with central domes were identified in images covering approx. 50% of the surface. Owing to limitations in resolution, and viewing and illumination angles, the features identified are most likely a subset of dome craters. The sample appears to be sufficiently large to infer statistically meaningful trends. Dome craters appear to fall into two distinct populations on plots of the ratio of dome diameter to crater rim diameter, large-dome craters and small-dome craters. The two classes are morphologically distinct from one another. In general, large dome craters show little relief and their constituent landforms appear subdued with respect to fresh craters. The physical attributes of small-dome craters are more sharply defined, a characteristic they share with young impact craters of comparable size observed elsewhere in the solar system. Both types of dome craters exhibit central pits in which the dome is located. As it is difficult to produce domes by impact and/or erosional processes, an endogenic origin for the domes is reasonably inferred. Several hypotheses for their origin are proposed. These hypotheses are briefly reviewed

  3. Macula on Europa

    Science.gov (United States)

    1997-01-01

    This image of Europa, an icy satellite of Jupiter about the size of the Earth's Moon, was obtained from a range of 7415 miles (11933 kilometers) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans 30 miles by 57 miles (48 km by 91 km) and shows features as small as 800 feet (240 meters) across. The large circular feature centered in the upper middle of the image is called a macula, and could be the scar of a large meteorite impact. The surface of Europa is composed mostly of water ice, so large impact craters on Europa could look different from large bowl-shaped depressions formed by impact into rock, such as on the Moon. On Europa's icy surface, the original impact crater has been modified into a central zone of rugged topography surrounded by circular fractures which reflect adjustments to stress in the surrounding icy crust.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  4. The Ganymede Laser Altimeter (GALA)

    Science.gov (United States)

    Hussmann, H.

    2015-12-01

    The Ganymede Laser Altimeter (GALA) is one of the instruments selected for ESA's Jupiter Icy Moons Explorer (JUICE). A fundamental goal of any exploratory space mission is to characterize and measure the shape, topography, and rotation of the target bodies. A state of the art tool for this task is laser altimetry because it can provide absolute topographic height and position with respect to a body centered reference system. With respect to Ganymede, the GALA instrument aims at mapping of global, regional and local topography; confirming the global subsurface ocean and further characterization of the water-ice/liquid shell by monitoring the dynamic response of the ice shell to tidal forces; providing constraints on the forced physical librations and spin-axis obliquity; determining Ganymede's shape; obtaining detailed topographic profiles across the linear features of grooved terrain, impact structures, possible cryo-volcanic features and other different surface units; providing information about slope, roughness and albedo (at 1064nm) of Ganymede's surface. GALA uses the direct-detection (classical) approach of laser altimetry. Laser pulses are emitted at a wavelength of 1064 nm by using an actively Q-switched Nd:Yag laser. The pulse energy and pulse repetition frequency are 17 mJ at 30 Hz, respectively. The emission time of each pulse is measured by the detector. The beam is reflected from the surface and received at a 25 cm diameter F/1 telescope. The returning laser pulse is refocused onto a silicon avalanche photodiode (APD) through back-end optics including a narrow bandpass interference filter for isolating the 1064 nm wavelength. The APD-signal is then amplified, sampled and fed to a digital range finder. The minimum acceptable SNR is approx. 1.2. This system determines the time of flight, pulse intensity, width and full shape. The GALA instrument is developed in collaboration of institutes and industry from Germany, Japan, Switzerland and Spain.

  5. Pensar Europa

    Directory of Open Access Journals (Sweden)

    Sonia Reverter

    2012-02-01

    Full Text Available Como dijo el profesor Fernando Montero "hay que reconocer que Europa es una extraña entidad, a mitad camino entre los seres reales y las ficciones". Desde el mismo mito de Europa, como princesa fenicia raptada por Zeus convertido en un toro blanco y llevada a Creta, hasta el discurso actual que promueve una idea de Europa como entidad transnacional, nos hallamos frente a la realidad de Europa como cuna de ideas e idea ella misma. La reflexividad que caracteriza al pensamiento filosófico y a la racionalidad crítica vuelve su mirada hacia la misma razón que se piensa, por tanto, a sí misma. Y es en ese punto en el que la cultura europea se ha destacado y tal vez debamos admitir también, se ha desgastado. Europa, desde la racionalidad de los griegos hasta la crisis de la razón actual ha pensado sobre sí misma al preguntarse por la razón misma. Podemos decir, de alguna manera, que Europa se piensa a sí misma al pensar en la razón humana. En este número monográfico de Recerca presentamos precisamente eso, una reflexión de Europa, que es a su vez una reflexión sobre algunos de los temas no sólo abiertos en ese quehacer constante que Europa se ha convertido, sino de gran calado para lo que Europa en un futuro pueda ser.

  6. Various Landscapes and Features on Europa

    Science.gov (United States)

    1997-01-01

    These 15 frames show the great variety of surface features on Jupiter's icy moon, Europa, which have been revealed by the Galileo spacecraft Solid State Imaging (CCD) system during its first six orbits around Jupiter from June 1996 to February 1997. North is to the top of each of the images. The features seen on Europa's surface document both internal and external processes shaping the icy crust. Internal processes and the possible presence of liquid water beneath the ice are indicated by features such as 'dark spots', lobe-shaped flow features, 'puddles','mottled terrain', knobs, pits, and the darker areas along ridges and triple bands.Europa is subjected to constant tugging from the giant planet, Jupiter, as well as from its neighboring moons, Io and Ganymede. This causes 'tidal' forces that affect Europa's interior and surface. Evidence for such forces includes ridges, fractures, wedge-shaped bands, and areas of 'chaos'. Some of these features result from alternate extension and compression buckling and pulling apart Europa's icy shell.Impact craters document external effects on a planet's surface. Although present on Europa, impact craters are relatively scarce compared to the number seen on Ganymede, Callisto, and on the surfaces of most other 'rocky' planets and moons in our solar system. This scarcity of craters suggests that the surface of Europa is very young. 'Maculae' on Europa may be the scars from large impact events.These images have resolutions from 27 meters (89 feet) to 7 kilometers (4.3 miles) per picture element (pixel) and were taken by Galileo at ranges of 2,500 kilometers (1,525 miles) to 677,000 kilometers (413,000 miles) from Europa.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo

  7. Ganymede's internal structure including thermodynamics of magnesium sulfate oceans in contact with ice

    Science.gov (United States)

    Vance, Steve; Bouffard, Mathieu; Choukroun, Mathieu; Sotin, Christophe

    2014-06-01

    The large icy moons of Jupiter contain vast quantities of liquid water, a key ingredient for life. Ganymede and Callisto are weaker candidates for habitability than Europa, in part because of the model-based assumption that high-pressure ice layers cover their seafloors and prevent significant water-rock interaction. Water-rock interactions may occur, however, if heating at the rock-ice interface melts the high pressure ice. Highly saline fluids would be gravitationally stable, and might accumulate under the ice due to upward migration, refreezing, and fractionation of salt from less concentrated liquids. To assess the influence of salinity on Ganymede's internal structure, we use available phase-equilibrium data to calculate activity coefficients and predict the freezing of water ice in the presence of aqueous magnesium sulfate. We couple this new equation of state with thermal profiles in Ganymede's interior-employing recently published thermodynamic data for the aqueous phase-to estimate the thicknesses of layers of ice I, III, V, and VI. We compute core and silicate mantle radii consistent with available constraints on Ganymede's mass and gravitational moment of inertia. Mantle radii range from 800 to 900 km for the values of salt and heat flux considered here (4-44 mW m-2 and 0 to 10 wt% MgSO4). Ocean concentrations with salinity higher than 10 wt% have little high pressure ice. Even in a Ganymede ocean that is mostly liquid, achieving such high ocean salinity is permissible for the range of likely S/Si ratios. However, elevated salinity requires a smaller silicate mantle radius to satisfy mass and moment-of-inertia constraints, so ice VI is always present in Ganymede's ocean. For lower values of heat flux, oceans with salinity as low as 3 wt% can co-exist with ice III. Available experimental data indicate that ice phases III and VI become buoyant for salinity higher than 5 wt% and 10 wt%, respectively. Similar behavior probably occurs for ice V at salinities

  8. Trajectory Design for the Europa Clipper Mission Concept

    Science.gov (United States)

    Buffington, Brent

    2014-01-01

    Europa is one of the most scientifically intriguing targets in planetary science due to its potential suitability for extant life. As such, NASA has funded the California Institute of Technology Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory to jointly determine and develop the best mission concept to explore Europa in the near future. The result of nearly 4 years of work--the Europa Clipper mission concept--is a multiple Europa flyby mission that could efficiently execute a number of high caliber science investigations to meet Europa science priorities specified in the 2011 NRC Decadal Survey, and is capable of providing reconnaissance data to maximize the probability of both a safe landing and access to surface material of high scientific value for a future Europa lander. This paper will focus on the major enabling component for this mission concept--the trajectory. A representative trajectory, referred to as 13F7-A21, would obtain global-regional coverage of Europa via a complex network of 45 flybys over the course of 3.5 years while also mitigating the effects of the harsh Jovian radiation environment. In addition, 5 Ganymede and 9 Callisto flybys would be used to manipulate the trajectory relative to Europa. The tour would reach a maximum Jovicentric inclination of 20.1 deg. have a deterministic (Delta)V of 164 m/s (post periapsis raise maneuver), and a total ionizing dose of 2.8 Mrad (Si).

  9. Rotational Dynamics of Icy Satellites : Tidal response and forced longitudinal librations at the surface of a viscoelastic Europa

    NARCIS (Netherlands)

    Jara Orue, H.M.

    2016-01-01

    The icy satellites of the giant planets Jupiter and Saturn are among the most interesting celestial bodies in our Solar System. The interpretation of various remote sensing observations performed by the Voyager, Galileo and Cassini-Huygens missions strongly suggests that many icy satellites harbor a

  10. Europa: Processes and Habitability

    Science.gov (United States)

    Pappalardo, Robert T.

    2006-01-01

    This viewgraph presentation reviews the known and possible geologic processes of Europa. It shows slides of Europa, with different terrains (ridged plains and molten plains), and a possible view of the interior. Europa's eccentric orbit is reviewed. The presentation also reviews Europa's composition. The possible reasons for Europa's geology are reviewed. Also the possiblity that life exists on Europa is raised. The planned Europa Geophysical Explorer mission is also reviewed.

  11. Relaxed impact craters on Ganymede: Regional variation and high heat flows

    Science.gov (United States)

    Singer, Kelsi N.; Bland, Michael T.; Schenk, Paul M.; McKinnon, William B.

    2018-01-01

    Viscously relaxed craters provide a window into the thermal history of Ganymede, a satellite with copious geologic signs of past high heat flows. Here we present measurements of relaxed craters in four regions for which suitable imaging exists: near Anshar Sulcus, Tiamat Sulcus, northern Marius Regio, and Ganymede's south pole. We describe a technique to measure apparent depth, or depth of the crater with respect to the surrounding terrain elevation. Measured relaxation states are compared with results from finite element modeling to constrain heat flow scenarios [see companion paper: Bland et al. (2017)]. The presence of numerous, substantially relaxed craters indicates high heat flows—in excess of 30–40 mW m−2 over 2 Gyr, with many small (heat flows. Crater relaxation states are bimodal for some equatorial regions but not in the region studied near the south pole, which suggests regional variations in Ganymede's thermal history.

  12. Relaxed impact craters on Ganymede: Regional variation and high heat flows

    Science.gov (United States)

    Singer, Kelsi N.; Bland, Michael T.; Schenk, Paul M.; McKinnon, William B.

    2018-05-01

    Viscously relaxed craters provide a window into the thermal history of Ganymede, a satellite with copious geologic signs of past high heat flows. Here we present measurements of relaxed craters in four regions for which suitable imaging exists: near Anshar Sulcus, Tiamat Sulcus, northern Marius Regio, and Ganymede's south pole. We describe a technique to measure apparent depth, or depth of the crater with respect to the surrounding terrain elevation. Measured relaxation states are compared with results from finite element modeling to constrain heat flow scenarios [see companion paper: Bland et al. (2017)]. The presence of numerous, substantially relaxed craters indicates high heat flows-in excess of 30-40 mW m-2 over 2 Gyr, with many small (heat flows. Crater relaxation states are bimodal for some equatorial regions but not in the region studied near the south pole, which suggests regional variations in Ganymede's thermal history.

  13. Europa central

    Directory of Open Access Journals (Sweden)

    Karel BARTOSEK

    2010-02-01

    Full Text Available La investigación francesa continúa interesándose por Europa Central. Desde luego, hay límites a este interés en el ambiente general de mi nueva patria: en la ignorancia, producto del largo desinterés de Francia por este espacio después de la Segunda Guerra Mundial, y en el comportamiento y la reflexión de la clase política y de los medios de comunicación (una anécdota para ilustrar este ambiente: durante la preparación de nuestro coloquio «Refugiados e inmigrantes de Europa Central en el movimiento antifascista y la Resistencia en Francia, 1933-1945», celebrado en París en octubre de 1986, el problema de la definición fue planteado concreta y «prácticamente». ¡Y hubo entonces un historiador eminente, para quién Alemania no formaría parte de Europa Central!.

  14. The Europa Clipper Mission Concept

    Science.gov (United States)

    Pappalardo, Robert; Goldstein, Barry; Magner, Thomas; Prockter, Louise; Senske, David; Paczkowski, Brian; Cooke, Brian; Vance, Steve; Wes Patterson, G.; Craft, Kate

    2014-05-01

    A NASA-appointed Science Definition Team (SDT), working closely with a technical team from the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL), recently considered options for a future strategic mission to Europa, with the stated science goal: Explore Europa to investigate its habitability. The group considered several mission options, which were fully technically developed, then costed and reviewed by technical review boards and planetary science community groups. There was strong convergence on a favored architecture consisting of a spacecraft in Jupiter orbit making many close flybys of Europa, concentrating on remote sensing to explore the moon. Innovative mission design would use gravitational perturbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of the moon's surface, with nominally 45 close flybys at altitudes from 25 to 100 km. We will present the science and reconnaissance goals and objectives, a mission design overview, and the notional spacecraft for this concept, which has become known as the Europa Clipper. The Europa Clipper concept provides a cost-efficient means to explore Europa and investigate its habitability, through understanding the satellite's ice and ocean, composition, and geology. The set of investigations derived from the Europa Clipper science objectives traces to a notional payload for science, consisting of: Ice Penetrating Radar (for sounding of ice-water interfaces within and beneath the ice shell), Topographical Imager (for stereo imaging of the surface), ShortWave Infrared Spectrometer (for surface composition), Neutral Mass Spectrometer (for atmospheric composition), Magnetometer and Langmuir Probes (for inferring the satellite's induction field to characterize an ocean), and Gravity Science (to confirm an ocean).The mission would also include the capability to perform reconnaissance for a future lander

  15. The Giant Planet Satellite Exospheres

    Science.gov (United States)

    McGrath, Melissa A.

    2014-01-01

    Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., lo, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

  16. Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A new technique to investigate Jovian upper atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tsumura, K. [Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Arimatsu, K.; Matsuura, S.; Shirahata, M.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronoutical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Egami, E. [Department of Astronomy, Arizona University, Tucson, AZ 85721 (United States); Hayano, Y.; Minowa, Y. [Hawaii Observatory, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Honda, C. [Research Center for Advanced Information Science and Technology, Aizu Research Cluster for Space Science, The University of Aizu, Aizu-Wakamatsu, Fukushima 965-8589 (Japan); Kimura, J. [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Kuramoto, K.; Takahashi, Y. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Nakajima, K. [Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Nakamoto, T. [Department of Earth and Planetary Sciences, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Surace, J., E-mail: tsumura@astr.tohoku.ac.jp [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-07-10

    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10{sup –6}-10{sup –7} of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

  17. Stratigraphy of the south polar region of Ganymede

    Science.gov (United States)

    Dehon, R. A.

    1987-01-01

    A preliminary assessment is made of the stratigraphy and geology in the south polar region of the Jovian satellite, Ganymede. Geologic mapping is based on inspection of Voyager images and compilation on an airbrush base map at a scale of 1:5M. Illumination and resolution vary greatly in the region. Approximately half of the quadripole is beyond the terminator. Low angle illumination over a large part of the area precludes distinction of some units by albedo characteristics. Several types of grooved terrain and groove related terrain occur in the southern polar region. Grooves typically occur in straight to curvilinear sets or lanes. Bright lanes and grooved lanes intersect at high angles outlining polygons of dark cratered terrain. Groove sets exhibit a range of ages as shown by superposition or truncation and by crater superposition ages.

  18. Biogeochemical Reactions Under Simulated Europa Ocean Conditions

    Science.gov (United States)

    Amashukeli, X.; Connon, S. A.; Gleeson, D. F.; Kowalczyk, R. S.; Pappalardo, R. T.

    2007-12-01

    Galileo data have demonstrated the probable presence of a liquid water ocean on Europa, and existence of salts and carbon dioxide in the satellite's surface ice (e.g., Carr et al., 1998; McCord et al., 1999, Pappalardo et al., 1999; Kivelson et al., 2000). Subsequently, the discovery of chemical signatures of extinct or extant life in Europa's ocean and on its surface became a distinct possibility. Moreover, understanding of Europa's potential habitability is now one of the major goals of the Europa Orbiter Flagship mission. It is likely, that in the early stages of Europa's ocean formation, moderately alkaline oceanic sulfate-carbonate species and a magnetite-silicate mantel could have participated in low-temperature biogeochemical sulfur, iron and carbon cycles facilitated by primitive organisms (Zolotov and Shock, 2004). If periodic supplies of fresh rock and sulfate-carbonate ions are available in Europa's ocean, then an exciting prospect exists that life may be present in Europa's ocean today. In our laboratory, we began the study of the plausible biogeochemical reactions under conditions appropriate to Europa's ocean using barophilic psychrophilic organisms that thrive under anaerobic conditions. In the near absence of abiotic synthetic pathways due to low Europa's temperatures, the biotic synthesis may present a viable opportunity for the formation of the organic and inorganic compounds under these extreme conditions. This work is independent of assumptions regarding hydrothermal vents at Europa's ocean floor or surface-derived oxidant sources. For our studies, we have fabricated a high-pressure (5,000 psi) reaction vessel that simulates aqueous conditions on Europa. We were also successful at reviving barophilic psychrophilic strains of Shewanella bacterium, which serve as test organisms in this investigation. Currently, facultative barophilic psychrophilic stains of Shewanella are grown in the presence of ferric food source; the strains exhibiting iron

  19. Exogenic and endogenic Europa minerals

    Science.gov (United States)

    Maynard-Casely, H. E.; Brand, H. E. A.; Wilson, S. A.

    2016-12-01

    The Galileo Near Infrared Mapping Spectrometer (NIMS) identified a significant `non-ice' component upon the surface of Jupiter's moon Europa. Current explanations invoke both endogenic and exogenic origins for this material. It has long been suggested that magnesium and sodium sulfate minerals could have leached from the rock below a putative ocean (endogenic) 1 and that sulfuric acid hydrate minerals could have been radiologically produced from ionised sulfur originally from Io's volcanoes (exogenic) 2. However, a more recent theory proposes that the `non-ice' component could be radiation damaged NaCl leached from Europa's speculative ocean 3. What if the minerals are actually from combination of both endogenic and exogenic sources? To investigate this possibility we have focused on discovering new minerals that might form in the combination of the latter two cases, that is a mixture of leached sulfates hydrates with radiologically produced sulfuric acid. To this end we have explored a number of solutions in the MgSO4-H2SO4-H2O and Na2SO4-H2SO4-H2O systems, between 80 and 280 K with synchrotron x-ray powder diffraction. We report a number of new materials formed in this these ternary systems. This suggests that it should be considered that the `non-ice' component of the Europa's surface could be a material derived from endogenic and exogenic components. 1 Kargel, J. S. Brine volcanism and the interior structures of asteroids and icy satellites. Icarus 94, 368-390 (1991). 2 Carlson, R. W., Anderson, M. S., Mehlman, R. & Johnson, R. E. Distribution of hydrate on Europa: Further evidence for sulfuric acid hydrate. Icarus 177, 461-471, doi:10.1016/j.icarus.2005.03.026 (2005). 3 Hand, K. P. & Carlson, R. W. Europa's surface color suggests an ocean rich with sodium chloride. Geophysical Research Letters, 2015GL063559, doi:10.1002/2015gl063559 (2015).

  20. Disturbances observed near Ganymede by Voyager 2

    International Nuclear Information System (INIS)

    Burlaga, L.F.; Belcher, J.W.; Ness, N.F.

    1980-01-01

    We investigated disturbances in the field and particle environment observed by Voyager 2 as it passed near the Jovian moon Ganymede in Jupiter's magnetosphere. The plasma analyzer observed at least a dozen sharply bounded depressions in density (cavities). We estimated that they probably extended at least 20 RGAMMA along the ambient magnetic field lines (R/sub G/=2635 km is the radius of Ganymede) and between 2--50 R/sub G/ in the directions transverse to B. Depressions in the magnetic field strength of the order of 5% of the ambient field strength (60nT to 135nT) were observed at the boundaries of the cavities in more than half of the cases; they were probably produced by currents flowing transverse to B on the boundaries. In some cases, the magnetic field strength inside the cavities was a few percent higher than the ambient value. This gives an upper limit on β=nkT/(B 2 /8π) outside the cavities, viz. Beta 2.5 MeV protons was strongly anti-correlated with the plasma density, the flux being higher inside the cavities than outside. One possible mechanism for the production of these flux enhancements and the cavities themselves is a local, magnetic field-aligned electric field, E. It is possible that Ganymede is responsible for the energetic protons in the cavities, in which case vertical-bar E vertical-barapprox.50 mV/m. Such a localized source implies radial motions of the magnetospheric plasma with speeds of the order of a few hundred km/s. Such motions could be produced by long-wavelength, small-amplitude Alfven waves in Jupiter's magnetosphere

  1. The Europa Global Geologic Map

    Science.gov (United States)

    Leonard, E. J.; Patthoff, D. A.; Senske, D. A.; Collins, G. C.

    2018-06-01

    The Europa Global Geologic Map reveals three periods in Europa's surface history as well as an interesting distribution of microchaos. We will discuss the mapping and the interesting implications of our analysis of Europa's surface.

  2. Ripple Ring Basins on Ganymede and Callisto

    Science.gov (United States)

    Croft, S. K.

    1985-01-01

    The unusual morphology of the Valhalla multiple or ripple-ring basin in Callisto was totally unexpected in light of the morphologies of large impact structures on the terrestrial planets. Two other ripple-ring basins (RRB's), Asgard and a smaller structure near the crater Adlinda are also described. Several additional RRB's were found on Callisto, an example of which is shown. A previously unrecognized RRB on Ganymede was also found. An image and geologic sketch map of this RRB are shown. Morphometric and positional data for all known RRB's are given.

  3. Understanding Regolith Physical Properties of Atmosphereless Solar System Bodies Based on Remote Sensing Photopolarimetric Observations: Evidence for Europa's Porous Surface

    Science.gov (United States)

    Nelson, R. M.; Boryta, M. D.; Hapke, B. W.; Manatt, K. S.; Shkuratov, Y.; Psarev, V.; Vandervoort, K.; Kroner, D. O.; Nebedum, A.; Vides, C.; Quinones, J.

    2017-12-01

    We studied the polarization and reflective properties of a suite of planetary regolith analogues with physical characteristics that might be expected to be found on a high albedo atmosphereless solar system body (ASSB). The angular scattering properties of thirteen well-sorted particle size fractions of aluminum oxide (Al2O3) were measured in the laboratory with a goniometric photopolarimeter (GPP) of unique design. Our results provide insight in support of efforts to understand the unusual reflectance and negative polarization behavior observed near small phase angles that has been reported over several decades on highly reflective ASSBs such as the asteroids 44 Nysa, 64 Angelina (Harris et al., 1989) and the Galilean satellites Io, Europa and Ganymede (Rosenbush et al., 1997; Mishchenko et al., 2006). Our measurements are consistent with the hypothesis that the surfaces of these ASSBs effectively scatter electromagnetic radiation as if they were extremely fine grained with void space > 95%, and grain sizes of the order landing on Europa's surface would require wheel or footpads that would protect it from settling deeply into the surface. These results also have relevance to the field of terrestrial geo-engineering particularly to proposals for modifying Earth's radiation balance by injecting high albedo Al2O3 particulates into Earth's atmosphere for the purpose of Solar Radiation Management by reflecting sunlight back into space hence, offsetting the global warming effects of anthropogenic greenhouse gas emissions such as carbon dioxide(Teller et al., 1997). This work partially supported by the Cassini Saturn Orbiter Progrem Harris et al., 1989 . Icarus 81, 365-374. Mishchenko et al., 2006 Applied Optics, 45, 4459-4463. Rosenbush et al, 1997, Astrophys. J. 487, 402-414. Teller et al., 1997. UCRL-JC-128715.

  4. Geology of Europa

    Science.gov (United States)

    Greeley, R.; Chyba, C.; Head, J. W.; McCord, T.; McKinnon, W. B.; Pappalardo, R. T.

    2004-01-01

    Europa is a rocky object of radius 1565 km (slightly smaller than Earth s moon) and has an outer shell of water composition estimated to be of order 100 km thick, the surface of which is frozen. The total volume of water is about 3 x 10(exp 9) cubic kilometers, or twice the amount of water on Earth. Moreover, like its neighbor Io, Europa experiences internal heating generated from tidal flexing during its eccentric orbit around Jupiter. This raises the possibility that some of the water beneath the icy crust is liquid. The proportion of rock to ice, the generation of internal heat, and the possibility of liquid water make Europa unique in the Solar System. In this chapter, we outline the sources of data available for Europa (with a focus on the Galileo mission), review previous and on-going research on its surface geology, discuss the astrobiological potential of Europa, and consider plans for future exploration.

  5. Three-layered models of Ganymede and Callisto - compositions, structures, and aspects of evolution

    International Nuclear Information System (INIS)

    Mueller, S.; Mckinnon, W.B.

    1988-01-01

    The structural models presently defined for Ganymede and Callisto, which encompass a pure-ice upper layer, a mixed ice/rock lower mantle, and a rock core, incorporate three alternative rock component candidates representing various degrees of silicate hydration and oxidation. The three-layered model facilitates close study of the radius increase required for the internal differentiation of an ice-rock satellite; such expansion is determined to be most significant early in the process, and less so as differentiation approaches completion. The probability of postaccretional melting due to radiogenic heating is calculated. 78 references

  6. Local-scale stratigraphy of grooved terrain on Ganymede

    Science.gov (United States)

    Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

    1987-01-01

    The surface of the Jovian satellite, Ganymede, is divided into two main units, dark terrain cut by arcuate and subradial furrows, and light terrain consisting largely of areas with pervasive U-shaped grooves. The grooved terrain may be subdivided on the basis of pervasive morphology of groove domains into four terrain types: (1) elongate bands of parallel grooves (groove lanes); (2) polygonal domains of parallel grooves (grooved polygons); (3) polygonal domains of two orthogonal groove sets (reticulate terrain); and (4) polygons having two to several complexly cross-cutting groove sets (complex grooved terrain). Reticulate terrain is frequently dark and not extensively resurfaced, and grades to a more hummocky terrain type. The other three grooved terrain types have almost universally been resurfaced by light material during their emplacement. The sequence of events during grooved terrain emplacement has been investigated. An attempt is made to integrate observed geologic and tectonic patterns to better constrain the relative ages and styles of emplacement of grooved terrain types. A revised model of grooved terrain emplacement is proposed and is tested using detailed geologic mapping and measurement of crater density.

  7. REASON for Europa

    Science.gov (United States)

    Moussessian, A.; Blankenship, D. D.; Plaut, J. J.; Patterson, G. W.; Gim, Y.; Schroeder, D. M.; Soderlund, K. M.; Grima, C.; Young, D. A.; Chapin, E.

    2015-12-01

    The science goal of the Europa multiple flyby mission is to "explore Europa to investigate its habitability". One of the primary instruments selected for the scientific payload is a multi-frequency, multi-channel ice penetrating radar system. This "Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON)" would revolutionize our understanding of Europa's ice shell by providing the first direct measurements of its surface character and subsurface structure. REASON addresses key questions regarding Europa's habitability, including the existence of any liquid water, through the innovative use of radar sounding, altimetry, reflectometry, and plasma/particles analyses. These investigations require a dual-frequency radar (HF and VHF frequencies) instrument with concurrent shallow and deep sounding that is designed for performance robustness in the challenging environment of Europa. The flyby-centric mission configuration is an opportunity to collect and transmit minimally processed data back to Earth and exploit advanced processing approaches developed for terrestrial airborne data sets. The observation and characterization of subsurface features beneath Europa's chaotic surface require discriminating abundant surface clutter from a relatively weak subsurface signal. Finally, the mission plan also includes using REASON as a nadir altimeter capable of measuring tides to test ice shell and ocean hypotheses as well as characterizing roughness across the surface statistically to identify potential follow-on landing sites. We will present a variety of measurement concepts for addressing these challenges.

  8. Science and Reconnaissance from the Europa Clipper Mission Concept: Exploring Europa's Habitability

    Science.gov (United States)

    Pappalardo, Robert; Senske, David; Prockter, Louise; Paczkowski, Brian; Vance, Steve; Goldstein, Barry; Magner, Thomas; Cooke, Brian

    2015-04-01

    capability to perform reconnais-sance for a future lander. In consultation with NASA Headquarters, the SDT developed a reconnaissance goal: Characterize Scientifically Compelling Sites, and Hazards, for a Potential Future Landed Mission to Europa. This leads to two reconnaissance objectives: Site Safety: Assess the distribution of surface hazards, the load-bearing capacity of the surface, the structure of the subsurface, and the regolith thickness; and Sci-ence Value: Assess the composition of surface materi-als, the geologic context of the surface, the potential for geological activity, the proximity of near surface water, and the potential for active upwelling of ocean material. The Europa Clipper mission concept provides an efficient means to explore Europa and investigate its habitability through understanding the satellite's ice shell and ocean, composition, and geology. It also provides for surface reconnaissance for potential future landed exploration of Europa. Development of the Eu-ropa Clipper mission concept is ongoing, with current studies focusing on spacecraft design trades and re-finements, launch vehicle options (EELV and SLS), and power source (MMRTG and solar), to name a few. We will provide an update on status of the science and reconnaissance effort, as well as the results of trade studies as relevant to the science and reconnaissance potential of the mission concept.

  9. Exploring Europa's Habitability: Science achieved from the Europa Orbiter and Clipper Mission Concepts

    Science.gov (United States)

    Senske, D. A.; Prockter, L. M.; Pappalardo, R. T.; Patterson, G. W.; Vance, S.

    2012-12-01

    Europa is a prime candidate in the search for present-day habitable environments in our solar system. Europa is unique among the large icy satellites because it probably has a saltwater ocean today beneath an ice shell that is geodynamically active. The combination of irradiation of its surface and tidal heating of its interior could make Europa a rich source of chemical energy for life. Perhaps most importantly, Europa's ocean is believed to be in direct contact with its rocky mantle, where conditions could be similar to those on Earth's biologically rich sea floor. Hydrothermal zones on Earth's seafloor are known to be rich with life, powered by energy and nutrients that result from reactions between the seawater and the warm rocky ocean floor. Life as we know it depends on three principal "ingredients": 1) a sustained liquid water environment; 2) essential chemical elements that are critical for building life; and 3) a source of energy that could be utilized by life. Europa's habitability requires understanding whether it possesses these three ingredients. NASA has enlisted a study team to consider Europa mission options feasible over the next decade, compatible with NASA's projected planetary science budget and addressing Planetary Decadal Survey priorities. Two Europa mission concepts (Orbiter and multiple flyby—call the "Clipper") are undergoing continued study with the goal to "Explore Europa to investigate its habitability." Each mission would address this goal in complementary ways, with high science value of its own. The Orbiter and Clipper architectures lend themselves to specific types of scientific measurements. The Orbiter concept is tailored to the unique geophysical science that requires being in orbit at Europa. This includes confirming the existence of an ocean and characterizing that ocean through geophysical measurements of Europa's gravitational tides and magnetic induction response. It also includes mapping of the global morphology and

  10. Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

    Science.gov (United States)

    Pettinelli, Elena; Cosciotti, Barbara; Di Paolo, Federico; Lauro, Sebastian Emanuel; Mattei, Elisabetta; Orosei, Roberto; Vannaroni, Giuliano

    2015-09-01

    The first European mission dedicated to the exploration of Jupiter and its icy moons (JUpiter ICy moons Explorer—JUICE) will be launched in 2022 and will reach its final destination in 2030. The main goals of this mission are to understand the internal structure of the icy crusts of three Galilean satellites (Europa, Ganymede, and Callisto) and, ultimately, to detect Europa's subsurface ocean, which is believed to be the closest to the surface among those hypothesized to exist on these moons. JUICE will be equipped with the 9 MHz subsurface-penetrating radar RIME (Radar for Icy Moon Exploration), which is designed to image the ice down to a depth of 9 km. Moreover, a parallel mission to Europa, which will host onboard REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) equipped with 9MHz and 60MHz antennas, has been recently approved by NASA. The success of these experiments strongly relies on the accurate prediction of the radar performance and on the optimal processing and interpretation of radar echoes that, in turn, depend on the dielectric properties of the materials composing the icy satellite crusts. In the present review we report a complete range of potential ice types that may occur on these icy satellites to understand how they may affect the results of the proposed missions. First, we discuss the experimental results on pure and doped water ice in the framework of the Jaccard theory, highlighting the critical aspects in terms of a lack of standard laboratory procedures and inconsistency in data interpretation. We then describe the dielectric behavior of extraterrestrial ice analogs like hydrates and icy mixtures, carbon dioxide ice and ammonia ice. Building on this review, we have selected the most suitable data to compute dielectric attenuation, velocity, vertical resolution, and reflection coefficients for such icy moon environments, with the final goal being to estimate the potential capabilities of the radar missions as a

  11. Active Cryovolcanism on Europa?

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, W. B.; Cracraft, M.; Deustua, S. E [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Schmidt, B. E. [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, 311 Ferst Drive, Atlanta, GA 30332 (United States); McGrath, M. A. [SETI Institute, 189 N. Bernardo Avenue, Mountain View, CA 94043 (United States); Hand, K. P. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Spencer, J. R., E-mail: sparks@stsci.edu [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2017-04-20

    Evidence for plumes of water on Europa has previously been found using the Hubble Space Telescope using two different observing techniques. Roth et al. found line emission from the dissociation products of water. Sparks et al. found evidence for off-limb continuum absorption as Europa transited Jupiter. Here, we present a new transit observation of Europa that shows a second event at the same location as a previous plume candidate from Sparks et al., raising the possibility of a consistently active source of erupting material on Europa. This conclusion is bolstered by comparison with a nighttime thermal image from the Galileo Photopolarimeter-Radiometer that shows a thermal anomaly at the same location, within the uncertainties. The anomaly has the highest observed brightness temperature on the Europa nightside. If heat flow from a subsurface liquid water reservoir causes the thermal anomaly, its depth is ≈1.8–2 km, under simple modeling assumptions, consistent with scenarios in which a liquid water reservoir has formed within a thick ice shell. Models that favor thin regions within the ice shell that connect directly to the ocean, however, cannot be excluded, nor modifications to surface thermal inertia by subsurface activity. Alternatively, vapor deposition surrounding an active vent could increase the thermal inertia of the surface and cause the thermal anomaly. This candidate plume region may offer a promising location for an initial characterization of Europa’s internal water and ice and for seeking evidence of Europa’s habitability.

  12. Descent with Modification: Thermal Reactions of Subsurface H2O2 of Relevance to Icy Satellites and Other Small Bodies

    Science.gov (United States)

    Hudson, Reggie L.; Loefler, Mark J.

    2012-01-01

    Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Similarly, cosmic radiation (mainly protons) acting on cometary and interstellar ices can promote extensive chemical change. Among the products that have been identified in irradiated H20-ice is hydrogen peroxide (H202), which has been observed on Europa and is suspected on other worlds. Although the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, the thermally-induced solid-phase chemistry of H2O2 is largely unknown. Therefore, in this presentation we report new laboratory results on reactions at 50 - 130 K in ices containing H2O2 and other molecules, both in the presence and absence of H2O. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to SO4(2-). We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto. If other molecules prove to be just as reactive with frozen H2O2 then it may explain why H2O2 has been absent from surfaces of many of the small icy bodies that are known to be exposed to ionizing radiation. Our results also have implications for the survival of H2O2 as it descends towards a subsurface ocean on Europa.

  13. Material Units, Structures/Landforms, and Stratigraphy for the Global Geologic Map of Ganymede (1:15M)

    Science.gov (United States)

    Patterson, G. Wesley; Head, James W.; Collins, Geoffrey C.; Pappalardo, Robert T.; Prockter, Louis M.; Lucchitta, Baerbel K.

    2008-01-01

    In the coming year a global geological map of Ganymede will be completed that represents the most recent understanding of the satellite on the basis of Galileo mission results. This contribution builds on important previous accomplishments in the study of Ganymede utilizing Voyager data and incorporates the many new discoveries that were brought about by examination of Galileo data. Material units have been defined, structural landforms have been identified, and an approximate stratigraphy has been determined utilizing a global mosaic of the surface with a nominal resolution of 1 km/pixel assembled by the USGS. This mosaic incorporates the best available Voyager and Galileo regional coverage and high resolution imagery (100-200 m/pixel) of characteristic features and terrain types obtained by the Galileo spacecraft. This map has given us a more complete understanding of: 1) the major geological processes operating on Ganymede, 2) the characteristics of the geological units making up its surface, 3) the stratigraphic relationships of geological units and structures, and 4) the geological history inferred from these relationships. A summary of these efforts is provided here.

  14. Solar Electric Propulsion Triple-Satellite-Aided Capture With Mars Flyby

    Science.gov (United States)

    Patrick, Sean

    Triple-Satellite-aided-capture sequences use gravity-assists at three of Jupiter's four massive Galilean moons to reduce the DeltaV required to enter into Jupiter orbit. A triple-satellite-aided capture at Callisto, Ganymede, and Io is proposed to capture a SEP spacecraft into Jupiter orbit from an interplanetary Earth-Jupiter trajectory that employs low-thrust maneuvers. The principal advantage of this method is that it combines the ISP efficiency of ion propulsion with nearly impulsive but propellant-free gravity assists. For this thesis, two main chapters are devoted to the exploration of low-thrust triple-flyby capture trajectories. Specifically, the design and optimization of these trajectories are explored heavily. The first chapter explores the design of two solar electric propulsion (SEP), low-thrust trajectories developed using the JPL's MALTO software. The two trajectories combined represent a full Earth to Jupiter capture split into a heliocentric Earth to Jupiter Sphere of Influence (SOI) trajectory and a Joviocentric capture trajectory. The Joviocentric trajectory makes use of gravity assist flybys of Callisto, Ganymede, and Io to capture into Jupiter orbit with a period of 106.3 days. Following this, in chapter two, three more SEP low-thrust trajectories were developed based upon those in chapter one. These trajectories, devised using the high-fidelity Mystic software, also developed by JPL, improve upon the original trajectories developed in chapter one. Here, the developed trajectories are each three separate, full Earth to Jupiter capture orbits. As in chapter one, a Mars gravity assist is used to augment the heliocentric trajectories. Gravity-assist flybys of Callisto, Ganymede, and Io or Europa are used to capture into Jupiter Orbit. With between 89.8 and 137.2-day periods, the orbits developed in chapters one and two are shorter than most Jupiter capture orbits achieved using low-thrust propulsion techniques. Finally, chapter 3 presents an

  15. High spatial resolution radiation budget for Europe: derived from satellite data, validation of a regional model; Raeumlich hochaufgeloeste Strahlungsbilanz ueber Europa: Ableitung aus Satellitendaten, Validation eines regionalen Modells

    Energy Technology Data Exchange (ETDEWEB)

    Hollmann, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

    2000-07-01

    Since forty years instruments onboard satellites have been demonstrated their usefulness for many applications in the field of meteorology and oceanography. Several experiments, like ERBE, are dedicated to establish a climatology of the global Earth radiation budget at the top of the atmosphere. Now the focus has been changed to the regional scale, e.g. GEWEX with its regional sub-experiments like BALTEX. To obtain a regional radiation budget for Europe in the first part of the work the well calibrated measurements from ScaRaB (scanner for radiation budget) are used to derive a narrow-to-broadband conversion, which is applicable to the AVHRR (advanced very high resolution radiometer). It is shown, that the accuracy of the method is in the order of that from SCaRaB itself. In the second part of the work, results of REMO have been compared with measurements of ScaRaB and AVHRR for March 1994. The model reproduces the measurements overall well, but it is overestimating the cold areas and underestimating the warm areas in the longwave spectral domain. Similarly it is overestimating the dark areas and underestimating the bright areas in the solar spectral domain. (orig.)

  16. Microbial mats in Antarctica as models for the search of life on the Jovian moon Europa

    International Nuclear Information System (INIS)

    Dudeja, S.; Bhattacherjee, A.B.; Chela-Flores, J.

    2008-06-01

    The possibility of sulfur patches on the Jovian satellite Europa being of biogenic origin is discussed. The presence of microbial mats and the accumulation of sulfur on the surface of some Antarctic subglacial lakes are correlated with the sulfur traces found on Europa by means of microbiological processes. Special attention has been paid to the influence of temperature and radiation on the icy surface of this Jovian satellite. An optimum penetration depth to look for biomarkers is proposed based on biogeochemical parameters. (author)

  17. Viscous relaxation as a prerequisite for tectonic resurfacing on Ganymede: Insights from numerical models of lithospheric extension

    Science.gov (United States)

    Bland, Michael T.; McKinnon, William B.

    2018-05-01

    Ganymede's bright terrain formed during a near-global resurfacing event (or events) that produced both heavily tectonized and relatively smooth terrains. The mechanism(s) by which resurfacing occurred on Ganymede (e.g., cryovolcanic or tectonic), and the relationship between the older, dark and the younger, bright terrain are fundamental to understanding the geological evolution of the satellite. Using a two-dimensional numerical model of lithospheric extension that has previously been used to successfully simulate surface deformation consistent with grooved terrain morphologies, we investigate whether large-amplitude preexisting topography can be resurfaced (erased) by extension (i.e., tectonic resurfacing). Using synthetically produced initial topography, we show that when the total relief of the initial topography is larger than 25-50 m, periodic groove-like structures fail to form. Instead, extension is localized in a few individual, isolated troughs. These results pose a challenge to the tectonic resurfacing hypothesis. We further investigate the effects of preexisting topography by performing suites of simulations initialized with topography derived from digital terrain models of Ganymede's surface. These include dark terrain, fresh (relatively deep) impact craters, smooth bright terrain, and a viscously relaxed impact crater. The simulations using dark terrain and fresh impact craters are consistent with our simulations using synthetic topography: periodic groove-like deformation fails to form. In contrast, when simulations were initialized with bright smooth terrain topography, groove-like deformation results from a wide variety of heat flow and surface temperature conditions. Similarly, when a viscously relaxed impact crater was used, groove-like structures were able to form during extension. These results suggest that tectonic resurfacing may require that the amplitude of the initial topography be reduced before extension begins. We emphasize that viscous

  18. The Europa Ocean Discovery mission

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, B.C. [Los Alamos National Lab., NM (United States); Chyba, C.F. [Univ. of Arizona, Tucson, AZ (United States); Abshire, J.B. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center] [and others

    1997-06-01

    Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`s surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges.

  19. Exploring Ocean-World Habitability within the Planned Europa Clipper Mission

    Science.gov (United States)

    Pappalardo, R. T.; Senske, D.; Korth, H.; Blaney, D. L.; Blankenship, D. D.; Collins, G. C.; Christensen, P. R.; Gudipati, M. S.; Kempf, S.; Lunine, J. I.; Paty, C. S.; Raymond, C. A.; Rathbun, J.; Retherford, K. D.; Roberts, J. H.; Schmidt, B. E.; Soderblom, J. M.; Turtle, E. P.; Waite, J. H., Jr.; Westlake, J. H.

    2017-12-01

    A key driver of planetary exploration is to understand the processes that lead to potential habitability across the solar system, including within oceans hosted by some icy satellites of the outer planets. In this context, it is the overarching science goal of the planned Europa Clipper mission is: Explore Europa to investigate its habitability. Following from this goal are three mission objectives: (1) Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; (2) Understand the habitability of Europa's ocean through composition and chemistry; and (3) Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. Folded into these objectives is the desire to search for and characterize any current activity, notably plumes and thermal anomalies. A suite of nine remote-sensing and in-situ observing instruments is being developed that synergistically addresses these objectives. The remote-sensing instruments are the Europa UltraViolet Spectrograph (Europa-UVS), the Europa Imaging System (EIS), the Mapping Imaging Spectrometer for Europa (MISE), the Europa THErMal Imaging System (E-THEMIS), and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The instruments providing in-situ observations are the Interior Characterization of Europa using Magnetometry (ICEMAG), the Plasma Instrument for Magnetic Sounding (PIMS), the MAss Spectrometer for Planetary EXploration (MASPEX), and the SUrface Dust Analyzer (SUDA). In addition, gravity science can be achieved via the spacecraft's telecommunication system, and the planned radiation monitoring system could provide information on Europa's energetic particle environment. Working together, the mission's robust investigation suite can be used to test hypotheses and enable discoveries relevant to the interior, composition, and geology of

  20. Akon - A Penetrator for Europa

    Science.gov (United States)

    Jones, Geraint

    2016-04-01

    Jupiter's moon Europa is one of the most intriguing objects in our Solar System. This 2000km-wide body has a geologically young solid water ice crust that is believed to cover a global ocean of liquid water. The presence of this ocean, together with a source of heating through tidal forces, make Europa a conceivable location for extraterrestrial life. The science case for exploring all aspects of this icy world is compelling. NASA has selected the Europa Mission (formerly Europa Clipper) to study Europa in detail in the 2020s through multiple flybys, and ESA's JUICE mission will perform two flybys of the body in the 2030s. The US agency has extended to the European Space Agency an invitation to provide a contribution to their mission. European scientists interested in Europa science and exploration are currently organizing themselves, in the framework of a coordinated Europa M5 Inititative to study concurrently the main options for this ESA contribution, from a simple addition of individual instruments to the NASA spacecraft, to a lander to investigate Europa's surface in situ. A high speed lander - a penetrator - is by far the most promising technology to achieve this latter option within the anticipated mass constraints, and studies of such a hard lander, many funded by ESA, are now at an advanced level. An international team to formally propose an Europa penetrator to ESA in response to the anticipated ESA M5 call is growing. The working title of this proposal is Akon (Άκων), named after the highly accurate javelin gifted to Europa by Zeus in ancient Greek mythology. We present plans for the Akon penetrator, which would impact Europa's surface at several hundred metres per second, and travel up to several metres into the moon's subsurface. To achieve this, the penetrator would be delivered to the surface by a dedicated descent module, to be destroyed on impact following release of the penetrator above the surface. It is planned that the instruments to be

  1. Polymerization of Building Blocks of Life on Europa and Other Icy Moons.

    Science.gov (United States)

    Kimura, Jun; Kitadai, Norio

    2015-06-01

    The outer Solar System may provide a potential habitat for extraterrestrial life. Remote sensing data from the Galileo spacecraft suggest that the jovian icy moons--Europa, Ganymede, and possibly Callisto--may harbor liquid water oceans underneath their icy crusts. Although compositional information required for the discussion of habitability is limited because of significantly restricted observation data, organic molecules are ubiquitous in the Universe. Recently, in situ spacecraft measurements and experiments suggest that amino acids can be formed abiotically on interstellar ices and comets. These amino acids could be continuously delivered by meteorite or comet impacts to icy moons. Here, we show that polymerization of organic monomers, in particular amino acids and nucleotides, could proceed spontaneously in the cold environment of icy moons, in particular the jovian icy moon Europa as a typical example, based on thermodynamic calculations, though kinetics of formation are not addressed. Observed surface temperature on Europa is 120 and 80 K in the equatorial region and polar region, respectively. At such low temperatures, Gibbs energies of polymerization become negative, and the estimated thermal structure of the icy crust should contain a shallow region (i.e., at a depth of only a few kilometers) favorable for polymerization. Investigation of the possibility of organic monomer polymerization on icy moons could provide good constraints on the origin and early evolution of extraterrestrial life.

  2. Digitalisierung des Kulturellen Erbes (Europas)

    NARCIS (Netherlands)

    Gruber, Marion

    2011-01-01

    Gruber, M. R. (2011, 13 December). Digitalisierung des Kulturellen Erbes (Europas). Guest lecture at the IPMZ - Institute of Mass Communication and Media Research, Devision Media Change & Innovation, University of Zurich, Switzerland.

  3. Europa Kinetic Ice Penetrator (EKIP)

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the proposed work is to validate an initial design for a Europa penetrator that can withstand the high g load associated with the expected hypervelocity...

  4. Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution

    Science.gov (United States)

    Wagner, R.; Neukum, G.; Wolf, U.; Greeley, R.; Klemaszewski, J. E.

    2003-04-01

    It has been conjectured that the projectile family which impacted the Galilean Satellites of Jupiter was depleted in large projectiles, concluded from a ''dearth'' in large craters (> 60 km) (e.g. [1]). Geologic mapping, aided by spatial filtering of new Galileo as well as older Voyager data shows, however, that large projectiles have left an imprint of palimpsests and multi-ring structures on both Ganymede and Callisto (e. g. [2]). Most of these impact structures are heavily degraded and hence difficult to recognize. In this paper, we present (1) maps showing the outlines of these basins, and (2) derive updated crater size-frequency diagrams of the two satellites. The crater diameter from a palimpsest diameter was reconstructed using a formula derived by [3]. The calculation of the crater diameter Dc from the outer boundary Do of a multi-ring structure is much less constrained and on the order of Dc = k \\cdot Do , with k ≈ 0.25-0.3 [4]. Despite the uncertainties in locating the ''true'' crater rims, the resulting shape of the distribution in the range from kilometer-sized craters to sizes of ≈ 500 km is lunar-like and strongly suggests a collisionally evolved projectile family, very likely of asteroidal origin. An alternative explanation for this shape could be that comets are collisionally evolved bodies in a similar way as are asteroids, which as of yet is still uncertain and in discussion. Also, the crater size distributions on Ganymede and Callisto are shifted towards smaller crater sizes compared to the Moon, caused by a much lower impact velocity of impactors which preferentially were in planetocentric orbits [5]. References: [1] Strom et al., JGR 86, 8659-8674, 1981. [2] J. E. Klemaszewski et al., Ann. Geophys. 16, suppl. III, 1998. [3] Iaquinta-Ridolfi &Schenk, LPSC XXVI (abstr.), 651-652, 1995. [4] Schenk &Moore, LPSC XXX, abstr. No. 1786 [CD-Rom], 1999. [5] Horedt & Neukum, JGR 89, 10,405-10,410, 1984.

  5. Habitability potential of satellites around Jupiter and Saturn

    Science.gov (United States)

    Coustenis, Athena; Raulin, Francois; Encrenaz, Therese; Grasset, Olivier; Solomonidou, Anezina

    2016-07-01

    In looking for habitable conditions in the outer solar system recent research focuses on the natural satellites rather than the planets themselves. Indeed, the habitable zone as traditionally defined may be larger than originally conceived. The outer solar system satellites provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the ground but also by the Voyager, Galileo and the Cassini spacecrafts revealed the potential of these satellites in this context, and our understanding of habitability in the solar system and beyond can be greatly enhanced by investigating several of these bodies together [1]. Their environments seem to satisfy many of the "classical" criteria for habitability (liquid water, energy sources to sustain metabolism and chemical compounds that can be used as nutrients over a period of time long enough to allow the development of life). Indeed, several of the moons show promising conditions for habitability and the development and/or maintenance of life. The strong gravitational pull caused by the giant planets may produce enough energy to sufficiently heat the cores of orbiting icy moons. Europa and Ganymede may be hiding, under their icy crust, putative undersurface liquid water oceans [2] which, in the case of Europa [3], may be in direct contact with a silicate mantle floor and kept warm by tidally generated heat [4]. Titan and Enceladus, Saturn's satellites, were found by the Cassini-Huygens mission to possess active organic chemistries with seasonal variations, unique geological features and possibly internal liquid water oceans. Titan's rigid crust and the probable existence of a subsurface ocean create an analogy with terrestrial-type plate tectonics, at least surficial [5], while Enceladus' plumes find an analogue in geysers. As revealed by Cassini the liquid hydrocarbon lakes [6] distributed mainly at polar latitudes on Titan are ideal isolated environments to look for

  6. Europa's Habitability follows from Classical Dynamical Astronomy

    Science.gov (United States)

    Greenberg, R.

    2001-11-01

    Celestial mechanics is responsible for Jupiter's satellite Europa being a possible site for life in the solar system. The Laplace orbital resonance drives a substantial eccentricity. The mutually dependent relationship between orbital and rotational evolution and tidal processes in turn controls Europa's heating and stress. Heat is likely adequate to maintain a liquid water ocean, and to keep the surface ice thin. Tidal stress can explain characteristic and ubiquitous crack patterns (global and cycloidal), as well as drive observed shear displacement features. The characteristic ridge sets that cover tectonic terrain are likely built by tidal pumping of oceanic fluid and slush through cracks to the surface on a daily basis. Nearly half the surface is chaotic terrain, with morphology and other characteristics indicative of melt-through from below. Formation of both chaotic and tectonic terrains has continually resurfaced the satellite, while connecting the ocean to the surface and providing a variety of evolving environmental niches. As a result of tides, liquid water would daily bathe crustal cracks and surfaces with heat, transporting and mixing substances vertically. Thus a variety of habitable environments likely exist in the crust. Moreover, exposure of the ocean to the surface in the ways described here satisfies a necessary condition for life in the ocean as well, by providing access to oxidants which are available near the surface. These processes were recent, and thus most likely continue today. Longer term changes in environmental conditions in the crust, such as deactivation of individual cracks after thousands of years (due to non-synchronous rotation) and later crustal thawing (releasing any trapped organisms), provided drivers for adaptation, as well as opportunity for evolution. This work is supported by the NASA Planetary Geology and Geophysics Program and the NSF Life in Extreme Environments Program.

  7. Europa: Initial Galileo Geological Observations

    Science.gov (United States)

    Greeley, R.; Sullivan, R.; Klemaszewski, J.; Homan, K.; Head, J. W.; Pappalardo, R.T.; Veverka, J.; Clark, B.E.; Johnson, T.V.; Klaasen, K.P.; Belton, M.; Moore, J.; Asphaug, E.; Carr, M.H.; Neukum, G.; Denk, T.; Chapman, C.R.; Pilcher, C.B.; Geissler, P.E.; Greenberg, R.; Tufts, R.

    1998-01-01

    Images of Europa from the Galileo spacecraft show a surface with a complex history involving tectonic deformation, impact cratering, and possible emplacement of ice-rich materials and perhaps liquids on the surface. Differences in impact crater distributions suggest that some areas have been resurfaced more recently than others; Europa could experience current cryovolcanic and tectonic activity. Global-scale patterns of tectonic features suggest deformation resulting from non-synchronous rotation of Europa around Jupiter. Some regions of the lithosphere have been fractured, with icy plates separated and rotated into new positions. The dimensions of these plates suggest that the depth to liquid or mobile ice was only a few kilometers at the time of disruption. Some surfaces have also been upwarped, possibly by diapirs, cryomagmatic intrusions, or convective upwelling. In some places, this deformation has led to the development of chaotic terrain in which surface material has collapsed and/or been eroded. ?? 1998 Academic Press.

  8. A Dynamical Systems Approach to the Design of the Science Orbit Around Europa

    Science.gov (United States)

    Gomez, Gerard; Lara, Martin; Russell, Ryan P.

    2006-01-01

    The science orbit for a future mission to Europa requires low eccentricity, low altitude, and high inclination. However, high inclination orbits around planetary satellites are unstable due to third-body perturbations. Without control, the orbiter impacts Europa after few weeks. To minimize control, a tour over the stable-unstable, averaged manifolds of unstable frozen orbits has been suggested. We proceed with the unaveraged equations and study the manifolds of unstable orbits that are periodic in a rotating frame attached to Europa. Massive numerical computation helps in understanding the unstable dynamics close to Europa, and, thus, in selecting long lifetime high inclination orbits. A final test of a selected set of initial conditions on a high fidelity, ephemeris model, validate the results.

  9. Europa como cultura

    Directory of Open Access Journals (Sweden)

    Javier San Martín

    2012-02-01

    Full Text Available El presente texto tiene un origen muy concreto. El día 15 de marzo de 2002, con motivo de la Cumbre Europea de Barcelona, Jorge Semprún reflexionaba, en las páginas de un conocido diario madrileño, sobre el significado que para él tenía ser europeo. Para ello emprendía tres "viajes intelectuales" a Viena, Praga y Buchenwald, los tres de gran significado histórico y cultural. Dado el interés del texto y del momento, me pareció entonces oportuno glosar algunos aspectos de aquel artículo, primero, para subrayar el valor de la aportación de Semprún, luego para corregir alguna inexactitud de carácter biográfico, debida posiblemente a la rapidez de la traducción, y, tercero, para ampliar con algún comentario la valiosa contribución de Sempnín, sobre todo en lo que concierne al sentido de Europa. En este texto se toma aquel comentario como punto de partida.The origins of this text are very specific. On 15 March 2002, on the occasion of the European Summit in Barcelona, and on the pages of a well-known Madrid newspaper, Jorge Semprún reflected on the meaning that being European had for him. To do this, he embarked on three "intellectual journeys" to Vienna, Prague and Buchenwald, all three of great historical and cultural significance. Given the interest of the text and of the moment, I considered it appropriate to comment on aspects of the article -firstly, to underline the value of Semprún's contribution; secondly, to correct certain biographical inaccuracies, possibly due to a hasty translation; and thirdly, to complement Semprún's valuable contribution, essentially concerning the meaning of Europe. This text takes that comment as its starting point.

  10. Inmigraciones en Europa

    Directory of Open Access Journals (Sweden)

    Cebrián, Juan A.

    2012-12-01

    Full Text Available In an interval of only six decades 1950-2010, we have witnessed the five centuries old emigration process interruption that has shaped modern European history. At the end of World War II begins an intense opposite migration flow from former European colonies to their historic metropolis, which had also incorporated other areas that never had that relationship of dependency. This phenomenon is undoubtedly the most important contemporary social process that has taken place in Europe. Such a transformation could only occur by the confluence of important complementary factors. In separate sections of this article we present the main causes of recent immigrations in Europe and what flows within Europe and from other continents can be identified. Second, we explore the key aspects of immigration: demographics, gender and labor market. Then, we study the problems of integration in the host societies and immigration policies that facilitate it. We ended our discussion with references to the singular case of Spain.

    En un intervalo de sólo seis décadas 1950-2010, hemos sido testigos de la interrupción del proceso multisecular emigratorio que ha marcado toda la historia moderna europea. Al término de la Segunda Guerra Mundial comienza un intenso reflejo de movilidad opuesta, desde las antiguas colonias europeas hacia su metrópoli histórica, que se ha contagiado también a otras áreas que nunca tuvieron esa relación de dependencia. Este fenómeno constituye, sin duda, el proceso social contemporáneo más importante que ha tenido lugar en Europa. Una transformación así sólo ha podido ocurrir por la confluencia de importantes factores complementarios. En diferentes apartados de este artículo exponemos las principales causas de la inmigración reciente en Europa y qué flujos intraeuropeos y procedentes de otros continentes pueden identificarse. En segundo término, nos interesamos por los aspectos claves del fenómeno inmigratorio

  11. On the origin of alkali metals in Europa exosphere

    Science.gov (United States)

    Ozgurel, Ozge; Pauzat, Françoise; Ellinger, Yves; Markovits, Alexis; Mousis, Olivier; LCT, LAM

    2016-10-01

    At a time when Europa is considered as a plausible habitat for the development of an early form of life, of particular concern is the origin of neutral sodium and potassium atoms already detected in its exosphere (together with magnesium though in smaller abundance), since these atoms are known to be crucial for building the necessary bricks of prebiotic species. However their origin and history are still poorly understood. The most likely sources could be exogenous and result from the contamination produced by Io's intense volcanism and/or by meteoritic bombardment. These sources could also be endogenous if these volatile elements originate directly from Europa's icy mantle. Here we explore the possibility that neutral sodium and potassium atoms were delivered to the satellite's surface via the upwelling of ices formed in contact with the hidden ocean. These metallic elements would have been transferred as ions to the ocean at early epochs after Europa's formation, by direct contact of water with the rocky core. During Europa's subsequent cooling, the icy layers formed at the top of the ocean would have kept trapped the sodium and potassium, allowing their future progression to the surface and final identification in the exosphere of the satellite. To support this scenario, we have used chemistry numerical models based on first principle periodic density functional theory (DFT). These models are shown to be well adapted to the description of compact ice and are capable to describe the trapping and neutralization of the initial ions in the ice matrix. The process is found relevant for all the elements considered, alkali metals like Na and K, as well as for Mg and probably for Ca, their respective abundances depending essentially of their solubility and chemical capabilities to blend with water ices.

  12. An Overview of the Jupiter Europa Orbiter Concept's Europa Science Phase Orbit Design

    Science.gov (United States)

    Lock, Robert E.; Ludwinski, Jan M.; Petropoulos, Anastassios E.; Clark, Karla B.; Pappalardo, Robert T.

    2009-01-01

    Jupiter Europa Orbiter (JEO), the proposed NASA element of the proposed joint NASA-ESA Europa Jupiter System Mission (EJSM), could launch in February 2020 and conceivably arrive at Jupiter in December of 2025. The concept is to perform a multi-year study of Europa and the Jupiter system, including 30 months of Jupiter system science and a comprehensive Europa orbit phase of 9 months. This paper provides an overview of the JEO concept and describes the Europa Science phase orbit design and the related science priorities, model pay-load and operations scenarios needed to conduct the Europa Science phase. This overview is for planning and discussion purposes only.

  13. GO JUP POS GLL TRAJECTORY MOON CENTERED COORDS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains Galileo trajectory data in moon (Amalthea, Io, Europa, Ganymede, Callisto) centered coordinates for all of the near satellite encounters....

  14. A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

    International Nuclear Information System (INIS)

    Hörst, S. M.; Brown, M. E.

    2013-01-01

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

  15. The ionosphere of Europa from Galileo radio occultations

    Science.gov (United States)

    Kliore, A. J.; Hinson, D. P.; Flasar, F. M.; Nagy, A. F.; Cravens, T. E.

    1997-01-01

    The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required.

  16. Analysis of mutual events of Galilean satellites observed from VBO during 2014-2015

    Science.gov (United States)

    Vasundhara, R.; Selvakumar, G.; Anbazhagan, P.

    2017-06-01

    Results of analysis of 23 events of the 2014-2015 mutual event series from the Vainu Bappu Observatory are presented. Our intensity distribution model for the eclipsed/occulted satellite is based on the criterion that it simulates a rotational light curve that matches the ground-based light curve. Dichotomy in the scattering characteristics of the leading and trailing sides explains the basic shape of the rotational light curves of Europa, Ganymede and Callisto. In the case of Io, the albedo map (courtesy United States Geological Survey) along with global values of scattering parameters works well. Mean values of residuals in (O - C) along and perpendicular to the track are found to be -3.3 and -3.4 mas, respectively, compared to 'L2' theory for the seven 2E1/2O1 events. The corresponding rms values are 8.7 and 7.8 mas, respectively. For the five 1E3/1O3 events, the along and perpendicular to the track mean residuals are 5.6 and 3.2 mas, respectively. The corresponding rms residuals are 6.8 and 10.5 mas, respectively. We compare the results using the chosen model (Model 1) with a uniform but limb-darkened disc (Model 2). The residuals with Model 2 of the 2E1/2O1 and 1E3/1O3 events indicate a bias along the satellite track. The extent and direction of bias are consistent with the shift of the light centre from the geometric centre. Results using Model 1, which intrinsically takes into account the intensity distribution, show no such bias.

  17. High Resolution Integral Field Spectroscopy of Europa's Sodium Clouds: Evidence for a Component with Origins in Iogenic Plasma.

    Science.gov (United States)

    Schmidt, C.; Johnson, R. E.; Mendillo, M.; Baumgardner, J. L.; Moore, L.; O'Donoghue, J.; Leblanc, F.

    2015-12-01

    With the object of constraining Iogenic contributions and identifying drivers for variability, we report new observations of neutral sodium in Europa's exosphere. An R~20000 integral field spectrograph at McDonald Observatory is used to generate Doppler maps of sodium cloud structures with a resolution of 2.8 km/s/pixel. In the five nights of observations since 2011, measurements on UT 6.15-6.31 May 2015 uniquely feature fast (10s of km/s) neutral sodium clouds extending nearly 100 Europa radii, more distant than in any previous findings. During these measurements, the satellite geometry was favorable for the transfer of Na from Io to Europa, located at 1:55 to 4:00 and 3:38 to 4:39 Jovian local time, respectively. Eastward emission (away from Jupiter) extends 10-20 Europa radii retaining the moon's rest velocity, while westward emission blue-shifts with distance, and a broad range of velocities are measured, reaching at least 70 km/s at 80 Europa radii. These cloud features are distinct from Io's "banana" and "stream" features, the distant Jupiter-orbiting nebula, and from terrestrial OH and Na contaminant emissions. Io's production was quiescent during this observation, following an extremely active phase in February 2015. These results are consistent with previous findings that Europa's Na exosphere has peak emission between midnight and dawn Jovian local time and support the idea that sodium escape from Io can significantly enhance the emission intensity measured at Europa.

  18. Halotolerant and halophilic bacteria in the oceans of the icy satellites

    Science.gov (United States)

    Ramirez, S. I.; Montoya, L.; Avendaño, R.

    2013-05-01

    Halotolerant and halophilic prokaryotes require salt concentrations equal to or higher than those present at terrestrial oceans (Rothschild and Mancinelli, 2001). They are a particular kind of extremophiles and as expected, their halotolerance is mainly expressed in terms of a certain NaCl percentage, at least on Earth. With the discovery of putative salty liquid oceans beneath the iced surfaces of some of the satellites of Jupiter and Saturn (Mueller and McKinnon, 1988; Kargel et al., 2000; Zolotov, 2007), information about the impact of other types of salts, different from NaCl, on the growth of complex biological systems is necessary. We have found that when three specific bacteria strains are growing in media enriched with salts containing chaotropic and kosmotropic ions, their specific optimal growth value is modified (Montoya et al., 2010). The changes can be broadly explained in terms of the Hofmeister series (Zhang and Cremer, 2006). These results can be used to infer an extension in the limits of biological activity. For terrestrial organisms there is scarce information to determine the impact of another salt in the growth of an organism. In these sense we have found that when media enriched with magnesium sulfate (MgSO4) at water activity values (aw) similar to those reported as optimal for NaCl, their growth and tolerance is considerably enhanced. On the other hand, the combination of chaotropic and kosmotropic ions result in salts of astrobiological importance such as the sulphate already mentioned, carbonates or chlorides that can tentatively exist in the putative ocean of Europa, Ganymedes, or Enceladus or even at the subsurface of Mars. In this frame, we studied the growth rate of Halomonas halodurans, H. magadiensis and Bacillus pumillus when exposed to media enriched with NaCl, MgSO4, Mg(NO3)2, MgCl2, Na2SO4 and NH4SO4. Equivalent values of water activity (aw) for each salt were compared and correlated with microbial activity (Montoya et al., 2010

  19. A Pragmatic Path to Investigating Europa's Habitability

    Science.gov (United States)

    Pappalardo; Bengenal; Bar; Bills; Blankenship; Connerney; Kurth; McGrath; Moore; Prockter; hide

    2011-01-01

    Assessment of Europa's habitability, as an overarching science goal, will progress via a comprehensive investigation of Europa's subsurface ocean, chemical composition, and internal dynamical processes, The National Research Council's Planetary Decadal Survey placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (1EO) mission concept is incompatible with NASA's projected planetary science budget Thus, NASA enlisted a small Europa Science Definition Team (ESDT) to consider more pragmatic Europa mission options, In its preliminary findings (May, 2011), the ESDT embraces a science scope and instrument complement comparable to the science "floor" for JEO, but with a radically different mission implementation. The ESDT is studying a two-element mission architecture, in which two relatively low-cost spacecraft would fulfill the Europa science objectives, An envisioned Europa orbital element would carry only a very small geophysics payload, addressing those investigations that are best carried out from Europa orbit An envisioned separate multiple Europa flyby element (in orbit about Jupiter) would emphasize remote sensing, This mission architecture would provide for a subset of radiation-shielded instruments (all relatively low mass, power, and data rate) to be delivered into Europa orbit by a modest spacecraft, saving on propellant and other spacecraft resources, More resource-intensive remote sensing instruments would achieve their science objectives through a conservative multiple-flyby approach, that is better situated to handle larger masses and higher data volumes, and which aims to limit radiation exposure, Separation of the payload into two spacecraft elements, phased in time, would permit costs to be spread more uniformly over mUltiple years, avoiding an excessively high peak in the funding profile, Implementation of each spacecraft would be greatly simplified compared to previous Europa mission

  20. Searching Less Perturbed Circular Orbits for a Spacecraft Travelling around Europa

    Directory of Open Access Journals (Sweden)

    J. P. S. Carvalho

    2014-01-01

    Full Text Available Space missions to visit the natural satellite of Jupiter, Europa, constitute an important topic in space activities today, because missions to this moon are under study now. Several considerations have to be made for these missions. The present paper searches for less perturbed circular orbits around Europa. This search is made based on the total effects of the perturbing forces over the time, evaluated by the integral of those forces over the time. This value depends on the dynamical model and on the orbit of the spacecraft. The perturbing forces considered are the third-body perturbation that comes from Jupiter and the J2, J3, and C22 terms of the gravitational potential of Europa. Several numerical studies are performed and the results show the locations of the less perturbed orbits. Using those results, it is possible to find near-circular frozen orbits with smaller amplitudes of variations of the orbital elements.

  1. Integration of CubeSat Systems with Europa Surface Exploration Missions

    Science.gov (United States)

    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.

  2. Jupiter Icy Moons Explorer (JUICE) : Science Objectives, Mission and Instruments (abstract)

    NARCIS (Netherlands)

    Gurvits, L.; Plaut, J.J.; Barabash, S.; Bruzzone, L.; Dougherty, M.; Erd, C.; Fletcher, L.; Gladstone, R.; Grasset, O.; Hartogh, P.; Hussmann, H.; Iess, L.; Jaumann, R.; Langevin, Y.; Palumbo, P.; Piccioni, G.; Titov, D.; Wahlund, J.E.

    2014-01-01

    The JUpiter ICy Moons Explorer (JUICE) is a European Space Agency mission that will fly by and observe the Galilean satellites Europa, Ganymede and Callisto, characterize the Jovian system in a lengthy Jupiter-orbit phase, and ultimately orbit Ganymede for in-depth studies of habitability, evolution

  3. The ``Perrier Oceans'' Of Europa And Enceladus (Invited)

    Science.gov (United States)

    Matson, D.; Johnson, T. V.; Lunine, J. I.; Castillo, J. C.

    2010-12-01

    Icy satellites of the outer solar system can have subsurface oceans that contain significant amounts of dissolved gases. Crawford and Stevenson in their 1988 study of Europa introduced the term “Perrier Ocean” as a descriptive appellation for such situations. When pressure is reduced, for example as a consequence of faulting, over water from a Perrier ocean, gas comes out of solution in the form of bubbles. The density of the liquid is immediately reduced, and if the bubble volume is sufficient the fluid can become buoyant with respect to the icy crust. If so, the seawater-bubble mixture can rise to the surface or very near to the surface. Europa and Enceladus may represent the end-member examples of Perrier oceans. Today, Europa appears passive whereas Enceladus is erupting. Some characteristics seen at Enceladus that may be indicative of an active Perrier ocean are eruptive plumes and localized, relatively warm (“hot-spot”) thermal anomalies of significantly high heat flow (i.e., >15 GW of integrated power over Enceladus’ South Polar Region). Since Enceladus is smaller than Europa it is easier for it to erupt because less work has to be done against gravity to bring water to the surface. Crawford and Stevenson found that under today’s conditions eruptions at Europa would be difficult but not necessarily impossible. However, in the past, when the icy crust was thinner, the interior warmer, eruption of liquid to the surface regions could have been easier. Morphological evidence for past eruptions from a Perrier ocean is not necessarily unambiguous in that it may admit alternate interpretations. However, the best evidence for relatively recent activity may be some sort of thermal signature. Such anomalies may be observable to depths of tens of meters in relatively clean ice by space-borne high-precision microwave radiometry and ground-penetrating radar. This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology under

  4. Surface composition of Europa based on VLT observations

    Science.gov (United States)

    Ligier, N.; Poulet, F.; Carter, J.

    2016-12-01

    Jupiter's moon Europa may harbor a global salty ocean under an 80-170 km thick outer layer consisting of an icy crust (Anderson et al. 1998). Meanwhile, the 10-50 My old surface, dated by cratering rates (Pappalardo et al. 1999) implies rapid surface recycling and reprocessing that could result in tectonic activity (Kattenhorn et al. 2014) and plumes (Roth et al. 2014). The surface could thus exhibit fingerprints of chemical species, as minerals characteristics of an ocean-mantle interaction and/or organics of exobiological interest, directly originating from the subglacial ocean. In order to re-investigate the composition of Europa's surface, a global mapping campaign of the satellite was performed with the near-infrared integral field spectrograph SINFONI on the Very Large Telescope (VLT) in Chile. The high spectral binning of this instrument (0.5 nm) and large signal noise ratio in comparison to previous observations are adequate to detect sharp absorptions in the wavelength range 1.45-2.45 μm. In addition, the spatially resolved spectra we obtained over five epochs nearly cover the entire surface of Europa with a pixel scale of 12.5 by 25 m.a.s ( 35 by 70 km on Europa's surface), thus permitting a global scale study. Several icy and non-icy compounds were detected and mapped at <100 km resolution. They are unevenly distributed on the moon's surface. Amorphous and crystalline water ice are both present and, in spite of a particularly strong amorphization process likely engendered by the Io plasma torus, the crystalline form is found to be approximately twice as abundant as the amorphous ice based on the analysis of the 1.65 μm band. If the surface is dominated by small and mid-sized water ice grains (25-200 μm), crystalline water-ice grains exhibit spatial inhomogeneities in their distribution. The sulfuric acid hydrate distribution exhibits the typical "bullseye" feature on the trailing hemisphere. The presence of Mg-bearing chlorinated salts (chloride

  5. Thick or Thin Ice Shell on Europa?

    Science.gov (United States)

    2007-01-01

    Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

  6. Review of exchange processes on Ganymede in view of its planetary protection categorization.

    Science.gov (United States)

    Grasset, O; Bunce, E J; Coustenis, A; Dougherty, M K; Erd, C; Hussmann, H; Jaumann, R; Prieto-Ballesteros, O

    2013-10-01

    In this paper, we provide a detailed review of Ganymede's characteristics that are germane to any consideration of its planetary protection requirements. Ganymede is the largest moon in our solar system and is the subject of one of the main science objectives of the JUICE mission to the jovian system. We explore the probability of the occurrence of potentially habitable zones within Ganymede at present, including those both within the deep liquid ocean and those in shallow liquid reservoirs. We consider the possible exchange processes between the surface and any putative habitats to set some constraints on the planetary protection approach for this moon. As a conclusion, the "remote" versus "significant" chance of contamination will be discussed, according to our current understanding of this giant icy moon. Based on the different estimates we investigate here, it appears extremely unlikely that material would be exchanged downward through the upper icy layer of Ganymede and, thus, bring material into the ocean over timescales consistent with the survival of microorganisms.

  7. Impact cratering experiments in Bingham materials and the morphology of craters on Mars and Ganymede

    Science.gov (United States)

    Fink, J. H.; Greeley, R.; Gault, D. E.

    1982-01-01

    Results from a series of laboratory impacts into clay slurry targets are compared with photographs of impact craters on Mars and Ganymede. The interior and ejecta lobe morphology of rampart-type craters, as well as the progression of crater forms seen with increasing diameter on both Mars and Ganymede, are equalitatively explained by a model for impact into Bingham materials. For increasing impact energies and constant target rheology, laboratory craters exhibit a morphologic progression from bowl-shaped forms that are typical of dry planetary surfaces to craters with ejecta flow lobes and decreasing interior relief, characteristic of more volatile-rich planets. A similar sequence is seen for uniform impact energy in slurries of decreasing yield strength. The planetary progressions are explained by assuming that volatile-rich or icy planetary surfaces behave locally in the same way as Bingham materials and produce ejecta slurries with yield strenghs and viscosities comparable to terrestrial debris flows. Hypothetical impact into Mars and Ganymede are compared, and it is concluded that less ejecta would be produced on Ganymede owing to its lower gravitational acceleration, surface temperature, and density of surface materials.

  8. MISE: A Search for Organics on Europa

    Science.gov (United States)

    Whalen, Kelly; Lunine, Jonathan I.; Blaney, Diana L.

    2017-01-01

    NASA’s planned Europa Flyby Mission will try to assess the habitability of Jupiter’s moon, Europa. One of the selected instruments on the mission is the Mapping Imaging Spectrometer for Europa (MISE). MISE is a near-infrared imaging spectrometer that takes spectra in the 0.8-5 micron range, and it will be capable of mapping Europa’s surface chemical composition. A primary goal of the MISE instrument is to determine if Europa is capable of supporting life by searching for amino acid signatures in the infrared spectra. We present spectra of pure amino acid at MISE’s resolution, and we analyze the effect of chirality on these spectra. Lastly, we present model spectra for diluted/mixed amino acids to simulate more realistic concentrations. We show MISE can distinguish between different types of amino acids, such as isoleucine, leucine, and their enantiomers.

  9. SLUSH: Europa Hybrid Deep Drill, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There are at least two fundamental design approaches one could use when trying to penetrate the icy shell on Europa and other planetary bodies: a melt probe and an...

  10. Seismometers on Europa: Insights from Modeling and Antarctic Ice Shelf Analogs (Invited)

    Science.gov (United States)

    Schmerr, N. C.; Brunt, K. M.; Cammarano, F.; Hurford, T. A.; Lekic, V.; Panning, M. P.; Rhoden, A.; Sauber, J. M.

    2013-12-01

    The outer satellites of the Solar System are a diverse suite of objects that span a large spectrum of sizes, compositions, and evolutionary histories; constraining their internal structures is key for understanding their formation, evolution, and dynamics. In particular, Jupiter's icy satellite Europa has compelling evidence for the existence of a global subsurface ocean beneath a surface layer of water ice. This ocean decouples the ice shell from the solid silicate mantle, and amplifies tidally driven large-scale surface deformation. The complex fissures and cracks seen by orbital flybys suggest brittle failure is an ongoing and active process in the ice crust, therefore indicating a high level of associated seismic activity. Seismic probing of the ice, oceanic, and rocky layers would provide altogether new information on the structure, evolution, and even habitability of Europa. Any future missions (penetrators, landers, and rovers) planning to take advantage of seismometers to image the Europan interior would need to be built around predictions for the expected background noise levels, seismicity, wavefields, and elastic properties of the interior. A preliminary suite of seismic velocity profiles for Europa has been calculated using moment of inertia constraints, planetary mass and density, estimates of moon composition, thermal structure, and experimentally determined relationships of elastic properties for relevant materials at pressure, temperature and depth. While the uncertainties in these models are high, they allow us to calculate a first-order seismic response using 1-D and 3-D high frequency wave propagation codes for global and regional scale structures. Here, we show how future seismic instruments could provide detailed elastic information and reduced uncertainties on the internal structure of Europa. For example, receiver functions and surface wave orbits calculated for a single seismic instrument would provide information on crustal thickness and

  11. Modeling Europa's Ice-Ocean Interface

    Science.gov (United States)

    Elsenousy, A.; Vance, S.; Bills, B. G.

    2014-12-01

    This work focuses on modeling the ice-ocean interface on Jupiter's Moon (Europa); mainly from the standpoint of heat and salt transfer relationship with emphasis on the basal ice growth rate and its implications to Europa's tidal response. Modeling the heat and salt flux at Europa's ice/ocean interface is necessary to understand the dynamics of Europa's ocean and its interaction with the upper ice shell as well as the history of active turbulence at this area. To achieve this goal, we used McPhee et al., 2008 parameterizations on Earth's ice/ocean interface that was developed to meet Europa's ocean dynamics. We varied one parameter at a time to test its influence on both; "h" the basal ice growth rate and on "R" the double diffusion tendency strength. The double diffusion tendency "R" was calculated as the ratio between the interface heat exchange coefficient αh to the interface salt exchange coefficient αs. Our preliminary results showed a strong double diffusion tendency R ~200 at Europa's ice-ocean interface for plausible changes in the heat flux due to onset or elimination of a hydrothermal activity, suggesting supercooling and a strong tendency for forming frazil ice.

  12. Between ice and gas: CO2 on the icy satellites of Jupiter and Saturn

    Science.gov (United States)

    Hibbitts, C.

    2010-12-01

    CO2 exists in the surfaces of the icy Galilean and Saturnian satellites [1-6], yet despite its discovery over a decade ago on Ganymede, and five years ago on the Saturnian satellites, its nature is still debated [7]. On the Galilean satellites Callisto and Ganymede, the CO2 that is detected is bound to, or trapped within, the non-ice materials that prevent it from sublimating or otherwise escaping from the surface. On Europa, it resides within both the ice and nonice materials [8,9]. While greater abundances of CO2 may exist in the interiors of these moons, or small amounts may be continually created through particle bombardment of the surface, the observed CO2 is only a trace material, with a few hundred molecules responsible for the deepest absorption features and an estimated molar abundance of 0.1% [2; 10-12]. Yet its presence may provide essential clues to processes that shape the surfaces of the moon [13] and potentially key to understanding the composition of potential oceans in the subsurfaces. We continue measurements of the infrared properties associated with CO2 adsorbed onto nonice materials under pressures and at temperatures relevant to these icy satellites using bidirectional reflectance spectroscopy from ~ 1.5 to 5.5 μm. Previous measurements, using transmission spectroscopy, demonstrated both a compositional and a temperature dependence on the spectral signature of adsorbed CO2 [14]. Bidirectional spectroscopy enables detection of lower concentrations of adsorbate on fine-grained materials such as clays due to their large surface area to volume ratios and thus large surface areas that may be covered by adsorbate [15]. The effectiveness of transmission spectroscopy was also limited by the strong absorption of light within the pressed sample and its impermeability, which limited the coverage by adsorbate to the pellet’s outer surface. All measurements demonstrate that CO2 adsorbs onto montmorillonite clays, possibly due to its quadrupole moment

  13. Viscosity of high-pressure ice VI and evolution and dynamics of Ganymede

    International Nuclear Information System (INIS)

    Poirier, J.P.; Sotin, C.; Peyronneau, J.

    1981-01-01

    The viscosity of high pressure ice VI has been measured at room temperature and pressures of 1.1 to 1.2 GPa giving a value of approximately equal to 10 14 P which suggests that solid state convection might have taken place during the early evolution of Ganymede, thus preventing melting and differentiation. Measurements were carried out in a sapphire anvil cell using fine particles to visualize the flow of ice down the radial pressure gradient. (U.K.)

  14. Ocean-driven heating of Europa's icy shell at low latitudes

    Science.gov (United States)

    Soderlund, K. M.; Schmidt, B. E.; Wicht, J.; Blankenship, D. D.

    2014-01-01

    The ice shell of Jupiter's moon Europa is marked by regions of disrupted ice known as chaos terrains that cover up to 40% of the satellite's surface, most commonly occurring within 40° of the equator. Concurrence with salt deposits implies a coupling between the geologically active ice shell and the underlying liquid water ocean at lower latitudes. Europa's ocean dynamics have been assumed to adopt a two-dimensional pattern, which channels the moon's internal heat to higher latitudes. Here we present a numerical model of thermal convection in a thin, rotating spherical shell where small-scale convection instead adopts a three-dimensional structure and is more vigorous at lower latitudes. Global-scale currents are organized into three zonal jets and two equatorial Hadley-like circulation cells. We find that these convective motions transmit Europa's internal heat towards the surface most effectively in equatorial regions, where they can directly influence the thermo-compositional state and structure of the ice shell. We suggest that such heterogeneous heating promotes the formation of chaos features through increased melting of the ice shell and subsequent deposition of marine ice at low latitudes. We conclude that Europa's ocean dynamics can modulate the exchange of heat and materials between the surface and interior and explain the observed distribution of chaos terrains.

  15. Heat transfer of ascending cryomagma on Europa

    Science.gov (United States)

    Quick, Lynnae C.; Marsh, Bruce D.

    2016-06-01

    Jupiter's moon Europa has a relatively young surface (60-90 Myr on average), which may be due in part to cryovolcanic processes. Current models for both effusive and explosive cryovolcanism on Europa may be expanded and enhanced by linking the potential for cryovolcanism at the surface to subsurface cryomagmatism. The success of cryomagma transport through Europa's crust depends critically on the rate of ascent relative to the rate of solidification. The final transport distance of cryomagma is thus governed by initial melt volume, ascent rate, overall ascent distance, transport mechanism (i.e., diapirism, diking, or ascent in cylindrical conduits), and melt temperature and composition. The last two factors are especially critical in determining the budget of expendable energy before complete solidification. Here we use these factors as constraints to explore conditions under which cryomagma may arrive at Europa's surface to facilitate cryovolcanism. We find that 1-5 km radius warm ice diapirs ascending from the base of a 10 km thick stagnant lid can reach the shallow subsurface in a partially molten state. Cryomagma transport may be further facilitated if diapirs travel along pre-heated ascent paths. Under certain conditions, cryolava transported from 10 km depths in tabular dikes or pipe-like conduits may reach the surface at temperatures exceeding 250 K. Ascent rates for these geometries may be high enough that isothermal transport is approached. Cryomagmas containing significant amounts of low eutectic impurities can also be delivered to Europa's surface by propagating dikes or pipe-like conduits.

  16. Denkers over eenwording van heinde en verre - Ghandi en Europa

    NARCIS (Netherlands)

    prof. dr. Ben Hoetjes

    2006-01-01

    Europa raakt in de publieke beeldvorming in Nederland duidelijk op de achtergrond. Andere zaken - het nieuwe zorgstelsel, de pensioenen, de misdaad, het internationale terrorisme, mensenrechtenschendingen, natuurrampen - hebben allang de voorpagina's overgenomen. Voor Europa-aanhangers zoals

  17. Europa Drum Sampler (EDuS), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of the proposed work is to develop a robust and effective sample acquisition system for the Europa lander called the Europa Drum Sampler (EDuS)....

  18. An ice crystal model for jupiter's moon Europa

    DEFF Research Database (Denmark)

    Dahl-Jensen, Dorthe; schmidt, Karen Guldbae

    2003-01-01

    A simple model for crystal growth in the ice shell of Europa has been made in order to estimate the size of ice crystals at Europa's surface. If mass is lost from the surface of Europa due to sputtering processes, and the ice thickness is constant in time, ice crystals will be transported upwards...

  19. Voorbij de retoriek: sociaal Europa vanuit twaalf invalshoeken

    NARCIS (Netherlands)

    van den Burg, I.; Cremers, J.; Hamans, C.; Pilon, A.

    2014-01-01

    Voorbij de retoriek. Sociaal Europa vanuit twaalf invalshoeken is een kritische analyse van de voorbije decennia, waarin het opbouwen van een sociaal Europa is achtergebleven bij het marktgerichte Europa. Wat zijn de oorzaken, de gevolgen en de oplossingen? En vooral: hoe zorgen we ervoor dat

  20. New observations on the crustacean fauna of Europa Island ...

    African Journals Online (AJOL)

    The Crustacea Decapoda of Europa Island have been inventoried during the BIORECIE fieldwork conducted from 7-12 November 2011. Previous records for Europa Island have been also compiled and an updated documented checklist of the species is proposed. In total, 175 decapods are reported for Europa Island, ...

  1. Power Subsystem Approach for the Europa Mission

    Directory of Open Access Journals (Sweden)

    Ulloa-Severino Antonio

    2017-01-01

    Full Text Available NASA is planning to launch a spacecraft on a mission to the Jovian moon Europa, in order to conduct a detailed reconnaissance and investigation of its habitability. The spacecraft would orbit Jupiter and perform a detailed science investigation of Europa, utilizing a number of science instruments including an ice-penetrating radar to determine the icy shell thickness and presence of subsurface oceans. The spacecraft would be exposed to harsh radiation and extreme temperature environments. To meet mission objectives, the spacecraft power subsystem is being architected and designed to operate efficiently, and with a high degree of reliability.

  2. Biomarker Production and Preservation on Europa

    Science.gov (United States)

    Buffo, J.; Schmidt, B. E.

    2017-12-01

    Future landing site selection and sampling techniques for Europa will concentrate on locations of high potential biomarker preservation, however it is unclear what the best targets might be. On Europa, the scenario is quite unlike the depositional surface environments of terrestrial planets we've studied thus far-Europa's surface is passively communicating with putative habitable niches below that extend throughout the ice shell, ocean and sea floor. In this work, I approach biomarker production and preservation on Europa based by considering the many hypotheses that govern the its habitability, the processes that occur within the sea floor, ocean, and ice and exchange between them, and the geologic hypotheses for the formation of its various surfaces to establish, what journey through the planet a biomarker might take to arrive, if possible, at the surface where it is accessible to near-term landed missions. The goal of this project is to construct a simple model through which to consider the context for sampled material that will provide us with the ability to identify limitations in our intuition, understanding of the Europan system, our current hypotheses and data, and provide a road map for developing both areas for new research and identifying technology gaps that we must overcome before we can confidently select a landing site or analyze a sample from the near surface of Europa. I first consider the nature of the environment, i.e. at the sea floor interface, the ocean, or ocean-ice interface, in order to establish what the likely "biomarker" could be and then trace its path through the system: downwelling through the shell, mixing through the ocean, and pathways to the surface. Importantly, many models exist for the production of Europa's surface and subsurface geology that could affect the integrity of a putative biomarker. Often we modulate such considerations as a function of the time-scales over which the geologic process occurs, however such processes

  3. Geodesy and cartography methods of exploration of the outer planetary systems: Galilean satellites and Enceladus

    Science.gov (United States)

    Zubarev, Anatoliy; Kozlova, Natalia; Kokhanov, Alexander; Oberst, Jürgen; Nadezhdina, Irina; Patraty, Vyacheslav; Karachevtseva, Irina

    Introduction. While Galilean satellites have been observed by different spacecrafts, including Pioneer, Voyager-1 and -2, Galileo, New Horizons, and Enceladus by Cassini and Voyager-2, only data from Galileo, Cassini and the two Voyagers are useful for precise mapping [1, 2]. For purposes of future missions to the system of outer planets we have re-computed the control point network of the Io, Ganymede and Enceladus to support spacecraft navigation and coordinate knowledge. Based on the control networks, we have produced global image mosaics and maps. Geodesy approach. For future mission Laplace-P we mainly focused on Ganymede which coverage is nearly complete except for polar areas (which includes multispectral data). However, large differences exist in data resolutions (minimum global resolution: 30 km/pixel). Only few areas enjoy coverage by highest resolution images, so we suggest to obtain regional Digital Elevation Models (DEMs) from stereo images for selected areas. Also using our special software, we provide calculation of illumination conditions of Ganymede surface in various representations [3]. Finally, we propose a careful evaluation of all available data from the previous Voyager and Galileo missions to re-determine geodetic control and rotation model for other Galilean satellites - Callisto and Europe. Mapping. Based on re-calculated control point networks and global mosaics we have prepared new maps for Io, Ganymede and Enceladus [4]. Due to the difference in resolution between the images, which were also taken from different angles relative to the surface, we can prepare only regional high resolution shape models, so for demonstrating of topography and mapping of the satellites we used orthographic projection with different parameters. Our maps, which include roughness calculations based on our GIS technologies [5], will also be an important tool for studies of surface morphology. Conclusions. Updated data collection, including new calculation of

  4. What causes an icy fault to slip? Investigating strike-slip failure conditions on Ganymede at Dardanus and Tiamat Sulcus.

    Science.gov (United States)

    Cameron, M. E.; Smith-Konter, B. R.; Burkhard, L. M.; Collins, G. C.; Seifert, F.; Pappalardo, R. T.

    2015-12-01

    Ganymede exhibits two geologically distinct terrains known as dark and light (grooved) terrain. The mechanism for a transition from dark to light terrain remains unclear; however, inferences of strike-slip faulting and distributed shear zones suggest that strike-slip tectonism may be important to the structural development of Ganymede's surface and in this transition. Here we investigate the role of tidal stresses on Ganymede in the formation and evolution of strike-slip structures in both dark and grooved terrains. Using numerical code SatStress, we calculate both diurnal and non-synchronous rotation (NSR) tidal stresses at Ganymede's surface. Specifically, we investigate the role of fault friction and orbital eccentricity in the development of ~45 km of right-lateral offset at Dardanus Sulcus and a possible case of study with a detailed morphological mapping of strike-slip morphologies (en echelon structures, strike-slip duplexes, laterally offset pre-existing features, and possible strained craters) at Nun Sulcus and several other locations. These structures serve as example regions to provide improved constraints for global stress mechanisms responsible for strike-slip fault evolution on Ganymede.

  5. Europa the ocean moon : search for an alien biosphere

    CERN Document Server

    Greenberg, Richard

    2004-01-01

    Europa - The Ocean Moon tells the story of the Galileo spacecraft probe to Jupiter's moon, Europa. It provides a detailed description of the physical processes, including the dominating tidal forces that operate on Europa, and includes a comprehensive tour of Europa using images taken by Galileo's camera. The book reviews and evaluates the interpretative work carried out to date, providing a philosophical discussion of the scientific process of analyzing results and the pitfalls that accompany it. It also examines the astrobiological constraints on this possible biosphere, and implications for future research, exploration and planetary biological protection. Europa - The Ocean Moon provides a unique understanding of the Galileo images of Europa, discusses the theory of tidal processes that govern its icy ridged and disrupted surface, and examines in detail the physical setting that might sustain extra-terrestrial life in Europa's ocean and icy crust.

  6. Hartvig Frisch og "Pest over Europa"

    DEFF Research Database (Denmark)

    Fledelius, Karsten

    2013-01-01

    Vil populistiske bevægelser i dagens Europa udhule demokratiet og skabe stater med en formel retsorden, som bliver vendt mod syndebukke og udnyttes til diskrimination af etniske, sociale og religiøse mindretal – som i 1930erne?...

  7. Europa's Compositional Evolution and Ocean Salinity

    Science.gov (United States)

    Vance, S.; Glein, C.; Bouquet, A.; Cammarano, F.; McKinnon, W. B.

    2017-12-01

    Europa's ocean depth and composition have likely evolved through time, in step with the temperature of its mantle, and in concert with the loss of water and hydrogen to space and accretion of water and other chemical species from comets, dust, and Io's volcanism. A key aspect to understanding the consequences of these processes is combining internal structure models with detailed calculations of ocean composition, which to date has not been done. This owes in part to the unavailability of suitable thermodynamic databases for aqueous chemistry above 0.5 GPa. Recent advances in high pressure aqueous chemistry and water-rock interactions allow us to compute the equilibrium ionic conditions and pH everywhere in Europa's interior. In this work, we develop radial structure and composition models for Europa that include self-consistent thermodynamics of all materials, developed using the PlanetProfile software. We will describe the potential hydration states and porosity of the rocky interior, and the partitioning of primordial sulfur between this layer, an underlying metallic core, and the ocean above. We will use these results to compute the ocean's salinity by extraction from the upper part of the rocky layer. In this context, we will also consider the fluxes of reductants from Europa's interior due to high-temperature hydrothermalism, serpentinization, and endogenic radiolysis.

  8. Core ethical values: EuropaBio.

    Science.gov (United States)

    2002-01-01

    EuropaBio, the European Association for BioIndustries, represents 40 companies operating world wide and 14 national association (totaling around 600 small and medium-sized enterprises) involved in the research, development, testing, manufacturing, marketing, sales and distribution of biotechnology products and services in the fields of healthcare, agriculture, food and the environment.

  9. Cryovolcanic Emplacement of Domes on Europa

    Science.gov (United States)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Stephen M.

    2016-01-01

    Here we explore the hypothesis that certain domes on Europa may have been produced by the extrusion of viscous cryolavas. A new mathematical method for the emplacement and relaxation of viscous lava domes is presented and applied to putative cryovolcanic domes on Europa. A similarity solution approach is applied to the governing equation for fluid flow in a cylindrical geometry, and dome relaxation is explored assuming a volume of cryolava has been rapidly emplaced onto the surface. Nonphysical sin- gularities inherent in previous models for dome relaxation have been eliminated, and cryolava cooling is represented by a time-variable viscosity. We find that at the onset of relaxation, bulk kinematic viscosities may lie in the range between 10(exp 3) and 10(exp 6) sq m/s, while the actual fluid lava viscosity may be much lower. Plausible relaxation times to form the domes, which are linked to bulk cryolava rheology, are found to range from 3.6 days to 7.5 years. We find that cooling of the cryolava, while dominated by conduction through an icy skin, should not prevent fluids from advancing and relaxing to form domes within the timescales considered. Determining the range of emplacement conditions for putative cryolava domes will shed light on Europa's resurfacing history. In addition, the rheologies and compositions of erupted cryolavas have implications for subsurface cryomagma ascent and local surface stress conditions on Europa.

  10. Forschung weltweit anerkannt: lernen von Europa

    CERN Multimedia

    Lorbeere, K

    2006-01-01

    Europa is better than its reputation. On one hand, the old continent, with the CERN, has the most modern research center for particle physics of the world; in addition, international groupings of companies as Microsoft use the research laboratories in Europe and thus use the know-how of the European scientists

  11. Tidally Driven Failure Along Europa's Rhadamanthys Linea

    Science.gov (United States)

    Cameron, M.; Konter, B.; Pappalardo, R. T.

    2013-12-01

    The surface of Europa is crosscut by a dense network of fractures and there are many candidate faults for studying past tectonic activity. To better understand the role of tidal stress sources and implications for faulting on Europa, we investigate the relationship between shear and normal stresses at Rhadamanthys Linea, a northwest oriented fracture in the northern hemisphere. Previous work on Agenor Linea, a right-lateral strike-slip fracture in the southern hemisphere, suggests that both tidal diurnal and non-synchronous rotation (NSR) stresses play a critical role in the mechanics of Coulomb shear failure on Europa. At Agenor Linea, shear failure from diurnal tidal stress mechanisms is difficult to achieve because the relatively large over¬burden stress (ie., 1.2 MPa at 1 km depth) dominates the stress field; however, MPa order stresses from NSR permit right-lateral shear failure along the west side of the fault at shallow depths (Astypalea Linea and Conamara Chaos will also be investigated, offering a unique comparison of geologic activity of fractures residing in geographically diverse locations of Europa.

  12. L'Europa accelera sul progetto Grid

    CERN Document Server

    2003-01-01

    "Il consorzio pan-europeo Egee sta pilotando a Bruxelles la complessa operazione che dotera' l'Europa di un mercato comune delle risorse di calcolo sulla base del modello Grid (griglia di calcolo, trasporto e distribuzione di dati)" (1 page).

  13. UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

    Science.gov (United States)

    Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

    2017-12-01

    Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details

  14. Magnetically-driven oceans on Jovian satellites

    Science.gov (United States)

    Gissinger, C.; Petitdemange, L.

    2017-12-01

    During the last decade, data from Galileo space missions have added strong support for the existence of subsurface liquid oceans on several moons of Jupiter. For instance, it is now commonly accepted that an electrically conducting fluid beneath the icy crust of Europa's surface may explain the variations of the induced field measured near the satellite. These observations have raised many questions regarding the size and the salinity of such subsurface ocean, or how and why the water remains liquid. In addition, the hydrodynamics of such oceans is mostly unknown. These questions are of primary importance since Europa is often considered as a good candidate for the presence of life beyond the Earth. Here, we present the first numerical modeling of the rapidly-rotating magnetohydrodynamic (MHD) flow generated in Europa's interior: due to Jupiter's rotation with respect to Europa, we show that the Lorentz force induced by the time-varying Jovian magnetic field is able to generate an oceanic flow of a few km/h. Our results are understood in the framework of a simple theoretical model and we obtain a scaling law for the prediction of the mean oceanic velocity and the total heating generated inside the ocean of Europa. Finally, by comparing our simulations to Galileo observations, we make predictions on both the thickness and the electrical conductivity of the ocean of different Jovian's satellites.

  15. Polar Plasma at Ganymede: Ionospheric outflow and discovery of the plasma sheet

    Science.gov (United States)

    Collinson, G.; Paterson, W.; Dorelli, J.; Glocer, A.; Sarantos, M.; Wilson, R. J.; Bard, C.

    2017-12-01

    On the 27th of June 1996, the NASA Galileo spacecraft made humanities first flyby of Jupiter's largest moon, Ganymede, discovering that it is unique to science in being the only moon known to possess an internally generated magnetic dynamo field. Although Galileo carried a plasma spectrometer, the Plasma Subsystem (PLS), converting its highly complex raw data stream into meaningful plasma moments (density, temperature, velocity) is extremely challenging, and was only ever performed for the second (out of six) Ganymede flybys. Resurrecting the original Galileo PLS data analysis software, we processed the raw PLS data from G01, and for the first time present the properties of plasmas encountered. Dense, cold ions were observed outflowing from the moon's north pole (presumed to be dominated by H+ from the icy surface), with more diffuse, warmer field-aligned outflows in the lobes. Dropouts in plasma density combined with velocity perturbations either side of this suggest that Galileo briefly crossed the cusps onto closed magnetic field lines. PLS observations show that upon entry into the magnetosphere, Galileo crossed through the plasma sheet, observing plasma flows consistent with reconnection-driven convection, highly energized 105 eV ions, and a reversal in the magnetic field. The densities of plasmas flowing upwards from Ganymede's ionosphere were higher on open "lobe" field lines than on closed field lines, suggesting that the ionospheric source of these plasmas may be denser at the poles, there may be additional acceleration mechanisms at play, or the balance of ions were outside the energy range of PLS.

  16. Thermal Reactions of H2O2 on Icy Satellites and Small Bodies: Descent with Modification?

    Science.gov (United States)

    Hudson, Reggie L.; Loeffler, Mark J.

    2012-01-01

    Magnetospheric radiation drives surface and near-surface chemistry on Europa, but below a few meters Europa's chemistry is hidden from direct observation . As an example, surface radiation chemistry converts H2O and SO2 into H2O2 and (SO4)(sup 2-), respectively, and these species will be transported downward for possible thermally-driven reactions. However, while the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, this molecule's thermally-induced solid-phase chemistry has seldom been studied. Here we report new results on thermal reactions in H2O + H2O2 + SO2 ices at 50 - 130 K. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to (SO4)(sup 2-). These results have implications for the survival of H2O2 as it descends, with modification, towards a subsurface ocean on Europa. We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

  17. Europa e Africa - Anatomia di un incontro

    DEFF Research Database (Denmark)

    Zoppi, Marco

    Available at: - http://ebook.edizionieiffel.com/product.php?id_product=36 or on AMAZON at:  http://www.amazon.it/Europa-Africa-Anatomia-Marco-Zoppi-ebook/dp/B01DPSBE6C/ref=sr_1_1?ie=UTF8&qid=1460205243&sr=8-1&keywords=marco+zoppi The book title translates as: "Europe and Africa: anatomy of an enc......Available at: - http://ebook.edizionieiffel.com/product.php?id_product=36 or on AMAZON at:  http://www.amazon.it/Europa-Africa-Anatomia-Marco-Zoppi-ebook/dp/B01DPSBE6C/ref=sr_1_1?ie=UTF8&qid=1460205243&sr=8-1&keywords=marco+zoppi The book title translates as: "Europe and Africa: anatomy...

  18. Praga, el Hollywood de Europa Oriental

    Directory of Open Access Journals (Sweden)

    Raúl Sorrosa

    2015-01-01

    Full Text Available Para salvar la industria fílmica checa, tuvieron que aliarse el mundo poscomunista y el capitalismo. Praga se ha convertido en "El Hollywood de Europa del Este" o en la Meca fílmica. Los estudios Barrandov después de la caída del comunismo y el proceso de transformación económico pasaron por la privatización.

  19. Seismic signal and noise on Europa

    Science.gov (United States)

    Panning, Mark; Stähler, Simon; Bills, Bruce; Castillo Castellanos, Jorge; Huang, Hsin-Hua; Husker, Allen; Kedar, Sharon; Lorenz, Ralph; Pike, William T.; Schmerr, Nicholas; Tsai, Victor; Vance, Steven

    2017-10-01

    Seismology is one of our best tools for detailing interior structure of planetary bodies, and a seismometer is included in the baseline and threshold mission design for the upcoming Europa Lander mission. Guiding mission design and planning for adequate science return, though, requires modeling of both the anticipated signal and noise. Assuming ice seismicity on Europa behaves according to statistical properties observed in Earth catalogs and scaling cumulative seismic moment release to the moon, we can simulate long seismic records and estimate background noise and peak signal amplitudes (Panning et al., 2017). This suggests a sensitive instrument comparable to many broadband terrestrial instruments or the SP instrument from the InSight mission to Mars will be able to record signals, while high frequency geophones are likely inadequate. We extend this analysis to also begin incorporation of spatial and temporal variation due to the tidal cycle, which can help inform landing site selection. We also begin exploration of how chaotic terrane at the bottom of the ice shell and inter-ice heterogeneities (i.e. internal melt structures) may affect anticipated seismic observations using 2D numerical seismic simulations.M. P. Panning, S. C. Stähler, H.-H. Huang, S. D. Vance, S. Kedar, V. C. Tsai, W. T. Pike, R. D. Lorenz, “Expected seismicity and the seismic noise environment of Europa,” J. Geophys. Res., in revision, 2017.

  20. Dome shaped features on Europa's surface

    Science.gov (United States)

    1997-01-01

    The Solid State Imaging system aboard the spacecraft Galileo took this image of the surface of Europa on February 20, 1997 during its sixth orbit around Jupiter. The image is located near 16 North, 268 West; illumination is from the lower-right. The area covered is approximately 48 miles (80 kilometers) by 56 miles (95 kilometers) across. North is toward the top of the image.This image reveals that the icy surface of Europa has been disrupted by ridges and faults numerous times during its past. These ridges have themselves been disrupted by the localized formation of domes and other features that may be indicative of thermal upwelling of water from beneath the crust. These features provide strong evidence for the presence of subsurface liquid during Europa's recent past.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  1. Shell Tectonics: A Mechanical Model for Strike-slip Displacement on Europa

    Science.gov (United States)

    Rhoden, Alyssa Rose; Wurman, Gilead; Huff, Eric M.; Manga, Michael; Hurford, Terry A.

    2012-01-01

    We introduce a new mechanical model for producing tidally-driven strike-slip displacement along preexisting faults on Europa, which we call shell tectonics. This model differs from previous models of strike-slip on icy satellites by incorporating a Coulomb failure criterion, approximating a viscoelastic rheology, determining the slip direction based on the gradient of the tidal shear stress rather than its sign, and quantitatively determining the net offset over many orbits. This model allows us to predict the direction of net displacement along faults and determine relative accumulation rate of displacement. To test the shell tectonics model, we generate global predictions of slip direction and compare them with the observed global pattern of strike-slip displacement on Europa in which left-lateral faults dominate far north of the equator, right-lateral faults dominate in the far south, and near-equatorial regions display a mixture of both types of faults. The shell tectonics model reproduces this global pattern. Incorporating a small obliquity into calculations of tidal stresses, which are used as inputs to the shell tectonics model, can also explain regional differences in strike-slip fault populations. We also discuss implications for fault azimuths, fault depth, and Europa's tectonic history.

  2. Top-down freezing in a Fe-FeS core and Ganymede's present-day magnetic field

    Science.gov (United States)

    Rückriemen, Tina; Breuer, Doris; Spohn, Tilman

    2018-06-01

    Ganymede's core most likely possesses an active dynamo today, which produces a magnetic field at the surface of ∼ 719 nT. Thermochemical convection triggered by cooling of the core is a feasible power source for the dynamo. Experiments of different research groups indicate low pressure gradients of the melting temperatures for Fe-FeS core alloys at pressures prevailing in Ganymede's core ( < 10 GPa). This may entail that the core crystallizes from the top instead of from the bottom as is expected for Earth's core. Depending on the core sulfur concentration being more iron- or more sulfur-rich than the eutectic concentration either snowing iron crystals or a solid FeS layer can form at the top of the core. We investigate whether these two core crystallization scenarios are capable of explaining Ganymede's present magnetic activity. To do so, we set up a parametrized one-dimensional thermal evolution model. We explore a wide range of parameters by running a large set of Monte Carlo simulations. Both freezing scenarios can explain Ganymede's present-day magnetic field. Dynamos of iron snow models are rather young ( < 1 Gyr), whereas dynamos below the FeS layer can be both young and much older ( ∼ 3.8 Gyr). Successful models preferably contain less radiogenic heat sources in the mantle than the chondritic abundance and show a correlation between the reference viscosity in the mantle and the initial core sulfur concentration.

  3. Low-Temperature Thermal Reactions Between SO2 and H2O2 and Their Relevance to the Jovian Icy Satellites

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2013-01-01

    Here we present first results on a non-radiolytic, thermally-driven reaction sequence in solid H2O +SO2 + H2O2 mixtures at 50-130 K, which produces sulfate (SO(-2)/(4)), and has an activation energy of 53 kJ/mole. We suspect that these results may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

  4. Fingerprints of endogenous process on Europa through linear spectral modeling of ground-based observations (ESO/VLT/SINFONI)

    Science.gov (United States)

    Ligier, Nicolas; Carter, John; Poulet, François; Langevin, Yves; Dumas, Christophe; Gourgeot, Florian

    2016-04-01

    Jupiter's moon Europa harbors a very young surface dated, based on cratering rates, to 10-50 M.y (Zahnle et al. 1998, Pappalardo et al. 1999). This young age implies rapid surface recycling and reprocessing, partially engendered by a global salty subsurface liquid ocean that could result in tectonic activity (Schmidt et al. 2011, Kattenhorn et al. 2014) and active plumes (Roth et al. 2014). The surface of Europa should contain important clues about the composition of this sub-surface briny ocean and about the potential presence of material of exobiological interest in it, thus reinforcing Europa as a major target of interest for upcoming space missions such as the ESA L-class mission JUICE. To perform the investigation of the composition of the surface of Europa, a global mapping campaign of the satellite was performed between October 2011 and January 2012 with the integral field spectrograph SINFONI on the Very Large Telescope (VLT) in Chile. The high spectral binning of this instrument (0.5 nm) is suitable to detect any narrow mineral signature in the wavelength range 1.45-2.45 μm. The spatially resolved spectra we obtained over five epochs nearly cover the entire surface of Europa with a pixel scale of 12.5 by 25 m.a.s (~35 by 70 km on Europa's surface), thus permitting a global scale study. Until recently, a large majority of studies only proposed sulfate salts along with sulfuric acid hydrate and water-ice to be present on Europa's surface. However, recent works based on Europa's surface coloration in the visible wavelength range and NIR spectral analysis support the hypothesis of the predominance of chlorine salts instead of sulfate salts (Hand & Carlson 2015, Fischer et al. 2015). Our linear spectral modeling supports this new hypothesis insofar as the use of Mg-bearing chlorines improved the fits whatever the region. As expected, the distribution of sulfuric acid hydrate is correlated to the Iogenic sulfur ion implantation flux distribution (Hendrix et al

  5. Studies of outer planet satellites, Mercury and Uranus

    Science.gov (United States)

    Mckinnon, William B.; Schenk, Paul M.

    1987-01-01

    Arguments were made, based on geometry, for both an impact and an internal origin for the ancient, partially preserved furrow system of Ganymede. It was concluded that furrows were not concentric, but could be impact related if multiringed structures on icy satellites are initially noncircular. The geometry of the Valhalla ring structure on Callisto was examined in order to assess the circularity of an unmodified ring system. The Ganymede furrow system was remapped to make use of improvements in coordinate control. The least-squares center of curvature for all furrows in the Marius and Galileao Regio is -20.7, and 179.2 degrees. Furrows in Marius and Galileo Regio are reasonably concentric, and are much more circular than previously estimated. The perceived present nonalignment of the assumed originally concentric furrows were used to argue for large-scale lateral motion of dark terrain blocks in Ganymede's crust, presumably in association with bright terrain formation., The overall alignment of furrows as well as the inherent scatter in centers of curvature from subregions of Galileo and Marius do not support this hypothesis.

  6. The Inferred Distribution of Liquid Water in Europa's Ice Shell: Implications for the Europa Lander Mission

    Science.gov (United States)

    Noviello, J. L.; Torrano, Z. A.; Rhoden, A.; Manga, M.

    2017-12-01

    A key objective of the Europa lander mission is to identify liquid water within 30 km of the lander (Europa Lander SDT report, 2017), to provide essential context with which to evaluate samples and enable assessment of Europa's overall habitability. To inform lander mission development, we utilize a model of surface feature formation that invokes liquid water within Europa's ice shell to map out the implied 3D distribution of liquid water and assess the likelihood of a lander to be within 30 km of liquid water given regional variability. Europa's surface displays a variety of microfeatures, also called lenticulae, including pits, domes, spots, and microchaos. A recent model by Manga and Michaut (2017) attributes these features to various stages in the thermal-mechanical evolution of liquid water intrusions (i.e. sills) within the ice shell, from sill emplacement to surface breaching (in the case of microchaos) to freezing of the sill. Pits are of particular interest because they appear only when liquid water is still present. Another key feature of the model is that the size of a microfeature at the surface is controlled by the depth of the sill. Hence, we can apply this model to regions of Europa that contain microfeatures to infer the size, depth, and spatial distribution of liquid water within the ice shell. We are creating a database of microfeatures that includes digitized, collated data from previous mapping efforts along with our own mapping study. We focus on images with 220 m/pixel resolution, which includes the regional mapping data sets. Analysis of a preliminary study area suggests that sills are typically located at depths of 2km or less from the surface. We will present analysis of the full database of microfeatures and the corresponding 3D distribution of sills implied by the model. Our preliminary analysis also shows that pits are clustered in some regions, consistent with previous results, although individual pits are also observed. We apply a

  7. De historische achtergronden van een Europa in crisis

    NARCIS (Netherlands)

    van Suijlekom, L.T.

    2012-01-01

    ‘Der Euro ist unser gemeinsames Schicksal, und Europa ist unsere gemeinsame Zukunft‘ verklaarde bondskanselier Angela Merkel in 2010. De economische en monetaire crisis in Europa zet EU-regeringsleiders onder druk om vergaande beslissingen te nemen welke bepalend zullen zijn voor de toekomst van

  8. Ad populum. Parlare alla pancia: retoriche del populismo in Europa

    Directory of Open Access Journals (Sweden)

    Yulia Ivanova

    2016-12-01

    Full Text Available Recensiamo il libro Ad populum. Parlare alla pancia: retorica del populismo in Europa. Eds. Bruno Capaci e Giuditta Spassini. Bologna: I libri di Emil di Odoya srl., 2016. Stampa. Review of Ad populum. Parlare alla pancia: retorica del populismo in Europa. Eds. Bruno Capaci and Giuditta Spassini. Bologna: I libri di Emil di Odoya srl., 2016. Print

  9. Tyskland kvæler Europas økonomi

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2012-01-01

    Tyskland dikterer økonomisk smalhals i Europa de næste mange år frem. Men spareiveren virker ikke og vil føre til mere arbejdsløshed samt større splittelse mellem Europas center og periferi. Så hvorfor ikke prøve noget andet?...

  10. Thera and Thrace Macula on Europa

    Science.gov (United States)

    1997-01-01

    This image of Europa's southern hemisphere was obtained by the solid state imaging (CCD) system on board NASA's Galileo spacecraft during its sixth orbit of Jupiter. The upper left portion of the image shows the southern extent of the 'wedges' region, an area that has undergone extensive disruption. South of the wedges, the eastern extent of Agenor Linea (nearly 1000 kilometers in length) is also visible. Thera and Thrace Macula are the dark irregular features southeast of Agenor Linea. This image can be used by scientists to build a global map of Europa by tying such Galileo images together with images from 1979 during NASA's Voyager mission. Such lower resolution images also provide the context needed to interpret the higher resolution images taken by the Galileo during both its nominal mission and the upcoming Europa mission. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at -40 latitude and 180 longitude, covers an area approximately 675 by 675 kilometers. The finest details that can be discerned in this picture are about 3.3 kilometers across. The images were taken on Feb 20, 1997 at 12 hours, 55 minutes, 34 seconds Universal Time when the spacecraft was at a range of 81,707 kilometers.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  11. Jupiter Europa Orbiter Architecture Definition Process

    Science.gov (United States)

    Rasmussen, Robert; Shishko, Robert

    2011-01-01

    The proposed Jupiter Europa Orbiter mission, planned for launch in 2020, is using a new architectural process and framework tool to drive its model-based systems engineering effort. The process focuses on getting the architecture right before writing requirements and developing a point design. A new architecture framework tool provides for the structured entry and retrieval of architecture artifacts based on an emerging architecture meta-model. This paper describes the relationships among these artifacts and how they are used in the systems engineering effort. Some early lessons learned are discussed.

  12. BIZANCIO, LOS ESLAVOS Y EUROPA ORIENTAL

    Directory of Open Access Journals (Sweden)

    José Marín Riveros

    2009-01-01

    Full Text Available Resumen: en este estudio, se presenta una reflexión acerca del concepto de Europa Oriental y, luego, una revisión de la historiografía acerca del origen de los eslavos, discutiendo las tesis tradicionales, la de Pritsak y la de Curta, según la etnogénesis, la etnonimia y la etnicidad.in this article, the author presents an analytical view about de concept "East Europe" and, then, an historiographical revision about the origin of the Slavic people, discussing the traditional thesis, Pritsak's thesis and Curta's thesis, i.e., commenting the ideas of ethnogenesis, ethnonimia and ethnicity.

  13. Can evolutionary convergence be tested on Europa?

    Energy Technology Data Exchange (ETDEWEB)

    Chela-Flores, Julian [Instituto de Estudios Avanzados, Caracas (Venezuela); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]. E-mail: chelaf@ictp.trieste.it

    2002-09-01

    A major objective in solar system exploration has to be the insertion of appropriate biology-oriented experiments in future missions. We discuss various reasons for suggesting that this type of research be considered a high priority for feasibility studies and, subsequently, for technological development of appropriate melters and submersibles. With the assumption that Darwin's theory is valid for the evolution of life anywhere in the universe, various degrees of convergent phenomena argue in favor of the conjecture that universal evolution of intelligent behavior is just a matter of time and preservation of steady planetary conditions. A preliminary test of this conjecture is feasible with experiments involving evolutionary biosignatures on Europa. (author)

  14. The Global Contribution of Secondary Craters on the Icy Satellites

    Science.gov (United States)

    Hoogenboom, T.; Johnson, K. E.; Schenk, P.

    2014-12-01

    At present, surface ages of bodies in the Outer Solar System are determined only from crater size-frequency distributions (a method dependent on an understanding of the projectile populations responsible for impact craters in these planetary systems). To derive accurate ages using impact craters, the impactor population must be understood. Impact craters in the Outer Solar System can be primary, secondary or sesquinary. The contribution of secondary craters to the overall population has recently become a "topic of interest." Our objective is to better understand the contribution of dispersed secondary craters to the small crater populations, and ultimately that of small comets to the projectile flux on icy satellites in general. We measure the diameters of obvious secondary craters (determined by e.g. irregular crater shape, small size, clustering) formed by all primary craters on Ganymede for which we have sufficiently high resolution data to map secondary craters. Primary craters mapped range from approximately 40 km to 210 km. Image resolution ranges from 45 to 440 m/pixel. Bright terrain on Ganymede is our primary focus. These resurfaced terrains have relatively low crater densities and serve as a basis for characterizing secondary populations as a function of primary size on an icy body for the first time. Although focusing on Ganymede, we also investigate secondary crater size, frequency, distribution, and formation, as well as secondary crater chain formation on icy satellites throughout the Saturnian and Jovian systems principally Rhea. We compare our results to similar studies of secondary cratering on the Moon and Mercury. Using Galileo and Voyager data, we have identified approximately 3,400 secondary craters on Ganymede. In some cases, we measured crater density as a function of distance from a primary crater. Because of the limitations of the Galileo data, it is necessary to extrapolate from small data sets to the global population of secondary craters

  15. Thermal probe design for Europa sample acquisition

    Science.gov (United States)

    Horne, Mera F.

    2018-01-01

    The planned lander missions to the surface of Europa will access samples from the subsurface of the ice in a search for signs of life. A small thermal drill (probe) is proposed to meet the sample requirement of the Science Definition Team's (SDT) report for the Europa mission. The probe is 2 cm in diameter and 16 cm in length and is designed to access the subsurface to 10 cm deep and to collect five ice samples of 7 cm3 each, approximately. The energy required to penetrate the top 10 cm of ice in a vacuum is 26 Wh, approximately, and to melt 7 cm3 of ice is 1.2 Wh, approximately. The requirement stated in the SDT report of collecting samples from five different sites can be accommodated with repeated use of the same thermal drill. For smaller sample sizes, a smaller probe of 1.0 cm in diameter with the same length of 16 cm could be utilized that would require approximately 6.4 Wh to penetrate the top 10 cm of ice, and 0.02 Wh to collect 0.1 g of sample. The thermal drill has the advantage of simplicity of design and operations and the ability to penetrate ice over a range of densities and hardness while maintaining sample integrity.

  16. Life habitability in the solar system: testing the universality of biology on Europa with microprobes or lander

    International Nuclear Information System (INIS)

    Chela-Flores, J.

    2007-05-01

    We discuss whether it is possible to test the universality of biology, a quest that is of paramount relevance for one of its most recent branches, namely astrobiology. We review this topic in terms of the relative roles played on the Earth biota by contingency and evolutionary convergence. We raise the related question of whether the molecular events that were precursors to the origin of life on Earth are bound to occur elsewhere in the solar system, wherever the environmental conditions are similar to the terrestrial ones. The set of hypotheses for addressing the question of the universality of biology can be tested by future experiments that are feasible with current technology. We focus on landing on the Jovian satellite Europa and its broader implications, including selecting a landing site. We also discuss the corresponding miniaturized equipment that is already in existence. The second objective is to discuss in more detail whether sulphur traces on Jupiter's moon Europa could be of biogenic origin, and could be tested with the present level of technology readiness. To achieve reliable biosignatures in the solar system in the foreseeable future, it seems essential to go back to Europa, in addition to continuing the multiple well-funded Mars programmes. Our work highlights the type of biogenic signatures that can be searched, when probing Europa's icy and patchy surface. Definite answers can be retrieved in situ on the icy surface with instrumentation for the corresponding biogeochemistry. The measurements can be performed by, for instance, microprobes, or by landers (of the type of the original JPL studies that sadly have been suspended). Such on-site measurements could make a modest contribution to the overall question of settling one of the most significant problems in astrobiology, namely the origin of the surficial sulphur on Europa. (author)

  17. Particulates in Europe; Fijn stof in Europa

    Energy Technology Data Exchange (ETDEWEB)

    Eeftens, M.; Brunekreef, B. [Institute for Risk Assessment Sciences IRAS, Utrecht University, Utrecht (Netherlands)

    2013-08-15

    Although the same air quality standards apply across Europe, there are large differences in concentration within, but also between countries. There are also differences between the methods that these countries use for regular monitoring networks, which makes a direct comparison of concentrations difficult. The ESCAPE project (European Study of Cohorts for Air Pollution Effects) mapped the differences in the European particulate concentrations using one unified measuring method [Dutch] Hoewel voor heel Europa dezelfde luchtkwaliteitsnormen gelden, bestaan er grote concentratieverschillen binnen, maar ook tussen landen. Ook zijn er verschillen tussen de meetmethoden die deze landen binnen reguliere meetnetten hanteren, wat een directe vergelijking van concentraties vaak moeilijk maakt. Het ESCAPE-project (European Study of Cohorts for Air Pollution Effects) bracht de Europese fijnstofcontrasten in kaart met behulp van 1 identieke meetmethode.

  18. El Orinoco ilustrado en la Europa dieciochesca

    OpenAIRE

    Andrés Castro Roldán

    2011-01-01

    El presente artículo estudia el fenómeno de la lectura en la Europa del siglo XVIII, a partir del caso del Orinoco ilustrado (1741-1745), del jesuita español José Gumilla. Se trata de una primera contribución al estudio de la recepción y la circulación de esta obra, a través de las múltiples lecturas que de Gumilla hicieron sus contemporáneos en España, Francia y los Países Bajos. El objetivo es poner esta obra en el contexto de su época, tanto desde el punto de vista literario como de la his...

  19. Flow-like Features On Europa

    Science.gov (United States)

    1997-01-01

    This image shows features on Jupiter's moon Europa that may be 'flows' from ice volcanoes. It was taken by the Galileo spacecraft solid state imaging (CCD) system during its seventh orbit around Jupiter. North is to the top of the image. The sun illuminates the scene from the left, showing features with shapes similar to lava flows on Earth. Two such features can be seen in the northwest corner of the image. The southern feature appears to have flowed over a ridge along its western edge. Scientists use these types of relationships to determine which feature formed first. In this case, the ridge probably formed before the flow-like feature that covers it.The image, centered at 22.6 degrees north latitude and 106.7 degrees west longitude, covers an area of 180 by 215 kilometers (112 by 134 miles). The smallest distinguishable features in the image are about 1.1 kilometers (0.7 miles) across. This image was obtained on April 28, 1997, when Galileo was 27,590 kilometers (16,830 miles) from Europa.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  20. The Plasma Instrument for Magnetic Sounding (PIMS) on The Europa Clipper Mission

    Science.gov (United States)

    Westlake, J. H.; McNutt, R. L., Jr.; Kasper, J. C.; Battista, C.; Case, A. W.; Cochrane, C.; Grey, M.; Jia, X.; Kivelson, M.; Kim, C.; Korth, H.; Khurana, K. K.; Krupp, N.; Paty, C. S.; Roussos, E.; Rymer, A. M.; Stevens, M. L.; Slavin, J. A.; Smith, H. T.; Saur, J.; Coren, D.

    2017-12-01

    The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. The Plasma Instrument for Magnetic Sounding (PIMS) on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa's magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa's surface into the atmosphere and ionosphere; and 3) understand how Europa influences its local space environment and Jupiter's magnetosphere and vice versa. Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa's ionosphere affecting the magnetic induction signal. Plasma from Io's temporally varying torus diffuses outward and mixes with the charged particles in Europa's own torus producing highly variable plasma conditions at Europa. PIMS works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa's subsurface ocean. This investigation exploits currents induced in Europa's interior by the moon's exposure to variable magnetic fields in the Jovian system to infer properties of Europa's subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa's global liquid ocean by

  1. Europa Nostra medal Tartusse / Karin Hallas-Murula

    Index Scriptorium Estoniae

    Hallas-Murula, Karin, 1957-

    2002-01-01

    Alvar Aalto projekteeritud Tammekannu villa (1932) Tartus pälvis Europa Nostra medali, mis antakse eriti õnnestunult renoveeritud objektile. Villa renoveeriti soome arhitekti Tapani Mustoneni projekti järgi

  2. Can the biogenicity of Europa's surfical sulfur be tested simultaneously with penetrators and ion traps?

    Science.gov (United States)

    Chela-Flores, J.; Bhattacherjee, A. B.; Dudeja, S.; Kumar, N.; Seckbach, J.

    2009-04-01

    with microbial mats—well understood in the context of the Antarctic dry valley lakes for the expulsion of a large quantity of sulfur—are used in tests on the icy surface of Europa, it is pertinent to evaluate the stopping-depth for the harsh radiation on the Europan surface. Recently, we have estimated the stopping-depth that should be probed by penetrators in proposed missions, such as LAPLACE, or in future projects. We find, in agreement with others (Greenberg, 2005), that beyond a few millimeters a penetrator would be testing biogeochemistry without any interference from radiation effects (Dudeja et al., 2009). Simultaneously with the penetrators there is an alternative suitable technology available. The isotopic S fractionation on the cloud surrounding Europa should reflect to a large extent the same biogenically-driven S fractionation that is taking place on the surface. We should recall that the origin of the cloud is due to particles that have been expelled by hypervelocity impacts of micrometeoroids on the surface. The instrumentation of ion-trap mass spectrometry has already been successfully completed for tests on a comet nucleus (the Ptolemy instrument and the Rosetta space mission). Ion traps have once again been in the planning stages for their eventual application in LAPLACE, or elsewhere (Todd et al., 2006; Taylor et al., 2007). Since the cloud around Europa is constantly being replenished by the above-mentioned micrometeorites, it would be reasonable to expect the cloud to mirror the large S-isotope deviations that may be caused locally by the assumed sulfate-reducing microorganisms. Consequently, dust detectors in orbit around this satellite should record similar large fluctuations of the Luria-Delbrück type that we have conjectured to take place on Europa's icy surface. This possibility has been explained in detail recently (Chela-Flores and Kumar, 2008). Consequently, we argue in favor that the instrumentation to be selected should include

  3. Morphology and Scaling of Ejecta Deposits on Icy Satellites

    Science.gov (United States)

    Schenk, Paul M.; Ridolfi, Francis J.; Bredekamp, Joe (Technical Monitor)

    2002-01-01

    Continuous ejecta deposits on Ganymede consist of two major units, or facies: a thick inner hummocky pedestal facies, and a relatively thin outer radially scoured facies defined also by the inner limit of the secondary crater field. Both ejecta facies have a well-defined power-law relationship to crater diameter for craters ranging from 15 to approx. 600 km across. This relationship can be used to estimate the nominal crater diameter for impact features on icy satellites (such as palimpsests and multiring basins) for which the crater rim is no longer recognizable. Ejecta deposits have also been mapped on 4 other icy satellites. Although morphologically similar to eject deposits on the Moon, ejecta deposits for smaller craters are generally significantly broader in extent on the icy satellites, in apparent defiance of predictions of self-similarity. A greater degree of rim collapse and enlargement on the Moon may explain the observed difference.

  4. Anaerobic Psychrophiles from Alaska, Antarctica, and Patagonia: Implications to Possible Life on Mars and Europa

    Science.gov (United States)

    Hoover, Richard B.; Pikuta, Elena V.; Marsic, Damien; Ng, Joseph

    2002-01-01

    Microorganisms preserved within the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, asteroids, comets or other frozen worlds in the Cosmos. The psychrophilic and psychrotolerant microbes of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to where and how we should search for evidence of life elsewhere in the Universe. For this reason, the cold-loving microorganisms are directly relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years. Permafrost, ice wedges, pingos, glaciers, and polar ice sheets may contain intact ancient DNA, lipids, enzymes, proteins, genes, and even frozen and yet viable ancient microbiota. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below 0 C. Complex microbial communities live in snow, ice-bubbles, cryoconite holes on glaciers and ancient microbial ecosystems are cryopreserved within the permafrost, glaciers, and polar caps. In the Astrobiology group of the NASA Marshall Space Flight Center and the University of Alabama at Huntsville, we have employed advanced techniques for the isolation, culture, and phylogenetic analysis of many types of microbial extremophiles. We have also used the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in ancient permafrost and ice. We discuss several interesting and novel anaerobic microorganisms that we have isolated and cultured from the Pleistocene ice of the Fox Tunnel of Alaska, guano of the Magellanic Penguin, deep-sea sediments from the vicinity of the Rainbow Hydrothermal Vent and enrichment cultures from ice of the Patriot Hills of Antarctica

  5. A Search for Signs of Life and Habitability on Europa

    Science.gov (United States)

    Fonda, Mark (Technical Monitor); McKay, Christoper P.; Eicken, H.; Neuer, S.; Sogin, M.; Waite, H.; Warmflash, D.

    2003-01-01

    Europa is a key target in the search for life beyond the Earth because of consistent evidence that below the icy surface there is liquid water. Future missions to Europa could confirm the presence and nature of the ocean and determine the thickness of the ice layer. Confirming the presence of an ocean and determining the habitability of Europa are key astrobiology science objectives. Nevertheless, the highest priority objective for astrobiology will be a search for life. How could a search for life be accomplished on a near-term mission given the thick ice cover? One answer may lie in the surface materials. If Europa has an ocean, and if that ocean contains life, and if water from the ocean is carried up to the surface, then signs of life may be contained in organic material on the surface. Organics that derive from biological processes (dead organisms) are distinct from organics derived from non-biological processes in several aspects. First, biology is selective and specific in its use of molecules. For example, Earth life uses 20 left-handed amino acids. Second, biology can leave characteristic isotopic patterns. Third, biology often produces large complex molecules in high concentrations, for example lipids. Organic material that has been on the surface of Europa for long periods of time would be reprocessed by the strong radiation field probably erasing any signature of biological origin. Evidence of life in the ocean may be found on the surface of Europa if regions of the surface contained relatively recent material carried up from the ocean through cracks in the icy lithosphere. But organic material that has been on the surface of Europa for long periods of time would be reprocessed by the strong radiation field probably erasing any signature of biological origin. Thus, the detailed analysis required may not be possible via remote sensing but direct sampling of the material below the radiation processed upper meter is probably required.

  6. Surface Modification and Surface - Subsurface Exchange Processes on Europa

    Science.gov (United States)

    Phillips, C. B.; Molaro, J.; Hand, K. P.

    2017-12-01

    The surface of Jupiter's moon Europa is modified by exogenic processes such as sputtering, gardening, radiolysis, sulfur ion implantation, and thermal processing, as well as endogenic processes including tidal shaking, mass wasting, and the effects of subsurface tectonic and perhaps cryovolcanic activity. New materials are created or deposited on the surface (radiolysis, micrometeorite impacts, sulfur ion implantation, cryovolcanic plume deposits), modified in place (thermal segregation, sintering), transported either vertically or horizontally (sputtering, gardening, mass wasting, tectonic and cryovolcanic activity), or lost from Europa completely (sputtering, plumes, larger impacts). Some of these processes vary spatially, as visible in Europa's leading-trailing hemisphere brightness asymmetry. Endogenic geologic processes also vary spatially, depending on terrain type. The surface can be classified into general landform categories that include tectonic features (ridges, bands, cracks); disrupted "chaos-type" terrain (chaos blocks, matrix, domes, pits, spots); and impact craters (simple, complex, multi-ring). The spatial distribution of these terrain types is relatively random, with some differences in apex-antiapex cratering rates and latitudinal variation in chaos vs. tectonic features. In this work, we extrapolate surface processes and rates from the top meter of the surface in conjunction with global estimates of transport and resurfacing rates. We combine near-surface modification with an estimate of surface-subsurface (and vice versa) transport rates for various geologic terrains based on an average of proposed formation mechanisms, and a spatial distribution of each landform type over Europa's surface area. Understanding the rates and mass balance for each of these processes, as well as their spatial and temporal variability, allows us to estimate surface - subsurface exchange rates over the average surface age ( 50myr) of Europa. Quantifying the timescale

  7. Understanding the Cryosphere of Europa Using Imaging Spectroscopy

    Science.gov (United States)

    Blaney, D. L.; Green, R. O.; Hibbitts, C.; Clark, R. N.; Dalton, J. B.; Davies, A. G.; Langevin, Y.; Hedman, M.; Lunine, J. I.; McCord, T. B.; Murchie, S. L.; Paranicas, C.; Seelos, F. P.; Soderblom, J. M.; Diniega, S.

    2017-12-01

    Europa's surface expresses a complex interplay of geologic processes driven by the ocean beneath the cryosphere that are subsequently modified by the Jovian environment once exposed on the surface. Several recent Earth-based observations of Europa's tenuous atmosphere suggest that there may in fact be active plumes [1,2,3]. However, the frequency and the duration of activity at any specific location cannot be precisely determined by these observations, but could be with spacecraft observations. For instance, recently active areas on Europa from plumes or other processes may result in distinctive spectral signatures on the surface. Possible spectral signatures that may indicate recent activity include: differences in ice grain size or ice crystallinity; the lack of radiolytic signatures (e.g. a deficit in species due to implantation, radiation darkening of salts, degradation of organic compounds); and thermal anomalies. The Mapping Imaging Spectrometer for Europa (MISE) on NASA's Europa Clipper Mission will be able to map these species thus enabling the identification of these deposits and other young and/or least processed areas. These signatures may also enable a relative geochronology for Europa to be developed. For example, recent work by Proctor et al [4] finds that bands of different stratigraphic ages have different spectral features potentially due to radiation effects on the deposits. We will explore borrowing analyses techniques from earth observing missions of the Arctic. On Earth, data from the Airborne Visible / Infrared Imaging Spectrometer Next Generation (AVRIS-NG) (https://avirisng.jpl.nasa.gov/aviris-ng.html) is being used to explore Earth's cryosphere. AVRIS-NG data collected from the Greenland ice sheet and high latitude sea ice is being used to map of key ice properties such as grain size and contaminants. These data and processing approaches will be used to explore and validate imaging spectroscopy approaches which MISE might use on Europa.

  8. Two-phase convection in Ganymede's high-pressure ice layer - Implications for its geological evolution

    Science.gov (United States)

    Kalousová, Klára; Sotin, Christophe; Choblet, Gaël; Tobie, Gabriel; Grasset, Olivier

    2018-01-01

    Ganymede, the largest moon in the solar system, has a fully differentiated interior with a layer of high-pressure (HP) ice between its deep ocean and silicate mantle. In this paper, we study the dynamics of this layer using a numerical model of two-phase ice-water mixture in two-dimensional Cartesian geometry. While focusing on the generation of water at the silicate/HP ice interface and its upward migration towards the ocean, we investigate the effect of bottom heat flux, the layer thickness, and the HP ice viscosity and permeability. Our results suggest that melt can be generated at the silicate/HP ice interface for small layer thickness ( ≲ 200 km) and high values of heat flux ( ≳ 20 mW m-2) and viscosity ( ≳ 1015 Pa s). Once generated, the water is transported through the layer by the upwelling plumes. Depending on the vigor of convection, it stays liquid or it may freeze before melting again as the plume reaches the temperate (partially molten) layer at the boundary with the ocean. The thickness of this layer as well as the amount of melt that is extracted from it is controlled by the permeability of the HP ice. This process constitutes a means of transporting volatiles and salts that might have dissolved into the melt present at the silicate/HP ice interface. As the moon cools down, the HP ice layer becomes less permeable because the heat flux from the silicates decreases and the HP ice layer thickens.

  9. Astrobiological Aspects of Radiation Chemistry in Europa's Icy Regolith

    Science.gov (United States)

    Carlson, R. W.; Hand, K. P.

    2006-05-01

    Jupiter's moon Europa, with its likely subsurface ocean and young, active surface, is a promising habitat for life. Europa orbits in the heart of Jupiter's powerful magnetosphere and suffers intense energetic particle bombardment, producing both positive and negative aspects for astrobiology at Europa. Ionizing radiation can produce oxidants that could support a radiation-driven ecology as proposed by Chyba. On the other hand, biomolecular evidence for life that may be upwelled to the surface is rapidly altered by irradiation, complicating astrobiological searches for evidence of life. We present an overview of laboratory work performed at JPL and elsewhere and observational results related to these two aspects. The oxidants hydrogen peroxide and molecular oxygen are known to exist on Europa and the radiolytic production of these species has been studied in the laboratory for both electron and ion irradiation. Laboratory- measured equilibrium concentrations of H2O2, where production and destruction rates are equal, are in general agreement with the observed 0.1% molar abundance on Europa. The shape of Europa's peroxide band is consistent with the line shapes observed in radiolysis and with H2O2 dispersed in water ice rather than occurring as H2O2 aggregates. Surprisingly, molecular oxygen may be even more abundant on Europa even though O2 is extremely volatile ande would be expected to escape from the ice surface. Radiolysis can produce molecular oxygen and appears to simultaneously alter the ice matrix, trapping the O2. Other species observed on Europa are CO2 and SO2, and laboratory radiolysis of these species in H2O ice produces carbonic and sulfuric acid, respectively. We are studying the radiolytic degradation of biomarkers in ice at Europa temperatures by studying both simple organics and more complex biomolecules, including microorganisms. Hydrocarbon radiolysis yields carbon dioxide and methane, which can escape the system and results in loss of carbon. In

  10. Tides on Europa: The membrane paradigm

    Science.gov (United States)

    Beuthe, Mikael

    2015-03-01

    Jupiter's moon Europa has a thin icy crust which is decoupled from the mantle by a subsurface ocean. The crust thus responds to tidal forcing as a deformed membrane, cold at the top and near melting point at the bottom. In this paper I develop the membrane theory of viscoelastic shells with depth-dependent rheology with the dual goal of predicting tidal tectonics and computing tidal dissipation. Two parameters characterize the tidal response of the membrane: the effective Poisson's ratio ν bar and the membrane spring constant Λ, the latter being proportional to the crust thickness and effective shear modulus. I solve membrane theory in terms of tidal Love numbers, for which I derive analytical formulas depending on Λ, ν bar , the ocean-to-bulk density ratio and the number k2∘ representing the influence of the deep interior. Membrane formulas predict h2 and k2 with an accuracy of a few tenths of percent if the crust thickness is less than one hundred kilometers, whereas the error on l2 is a few percents. Benchmarking with the thick-shell software SatStress leads to the discovery of an error in the original, uncorrected version of the code that changes stress components by up to 40%. Regarding tectonics, I show that different stress-free states account for the conflicting predictions of thin and thick shell models about the magnitude of tensile stresses due to nonsynchronous rotation. Regarding dissipation, I prove that tidal heating in the crust is proportional to Im (Λ) and that it is equal to the global heat flow (proportional to Im (k2)) minus the core-mantle heat flow (proportional to Im (k2∘)). As an illustration, I compute the equilibrium thickness of a convecting crust. More generally, membrane formulas are useful in any application involving tidal Love numbers such as crust thickness estimates, despinning tectonics or true polar wander.

  11. Thermal Conductivity Measurements on Icy Satellite Analogs

    Science.gov (United States)

    Javeed, Aurya; Barmatz, Martin; Zhong, Fang; Choukroun, Mathieu

    2012-01-01

    With regard to planetary science, NASA aspires to: "Advance scientific knowledge of the origin and history of the solar system, the potential for life elsewhere, and the hazards and resources present as humans explore space". In pursuit of such an end, the Galileo and Cassini missions garnered spectral data of icy satellite surfaces implicative of the satellites' structure and material composition. The potential for geophysical modeling afforded by this information, coupled with the plausibility of life on icy satellites, has pushed Jupiter's Europa along with Saturn's Enceladus and Titan toward the fore of NASA's planetary focus. Understanding the evolution of, and the present processes at work on, the aforementioned satellites falls squarely in-line with NASA's cited goal.

  12. Towards a Global Unified Model of Europa's Tenuous Atmosphere

    Science.gov (United States)

    Plainaki, Christina; Cassidy, Tim A.; Shematovich, Valery I.; Milillo, Anna; Wurz, Peter; Vorburger, Audrey; Roth, Lorenz; Galli, André; Rubin, Martin; Blöcker, Aljona; Brandt, Pontus C.; Crary, Frank; Dandouras, Iannis; Jia, Xianzhe; Grassi, Davide; Hartogh, Paul; Lucchetti, Alice; McGrath, Melissa; Mangano, Valeria; Mura, Alessandro; Orsini, Stefano; Paranicas, Chris; Radioti, Aikaterini; Retherford, Kurt D.; Saur, Joachim; Teolis, Ben

    2018-02-01

    Despite the numerous modeling efforts of the past, our knowledge on the radiation-induced physical and chemical processes in Europa's tenuous atmosphere and on the exchange of material between the moon's surface and Jupiter's magnetosphere remains limited. In lack of an adequate number of in situ observations, the existence of a wide variety of models based on different scenarios and considerations has resulted in a fragmentary understanding of the interactions of the magnetospheric ion population with both the moon's icy surface and neutral gas envelope. Models show large discrepancy in the source and loss rates of the different constituents as well as in the determination of the spatial distribution of the atmosphere and its variation with time. The existence of several models based on very different approaches highlights the need of a detailed comparison among them with the final goal of developing a unified model of Europa's tenuous atmosphere. The availability to the science community of such a model could be of particular interest in view of the planning of the future mission observations (e.g., ESA's JUpiter ICy moons Explorer (JUICE) mission, and NASA's Europa Clipper mission). We review the existing models of Europa's tenuous atmosphere and discuss each of their derived characteristics of the neutral environment. We also discuss discrepancies among different models and the assumptions of the plasma environment in the vicinity of Europa. A summary of the existing observations of both the neutral and the plasma environments at Europa is also presented. The characteristics of a global unified model of the tenuous atmosphere are, then, discussed. Finally, we identify needed future experimental work in laboratories and propose some suitable observation strategies for upcoming missions.

  13. Unmasking Europa the search for life on Jupiter's ocean moon

    CERN Document Server

    Greenberg, Richard

    2008-01-01

    Jupiter's ice moon Europa is widely regarded as the most likely place to find extraterrestrial life. This book tells the engaging story of Europa, the oceanic moon. It features a large number of stunning images of the ocean moon's surface, clearly displaying the spectacular crack patterns, extensive rifts and ridges, and refrozen pools of exposed water filled with rafts of displaced ice. Coverage also features firsthand accounts of Galileo's mission to Jupiter and its moons. The book tells the rough and tumble inside story of a very human enterprise in science that lead to the discovery of a f

  14. Occurrence and Detectability of Thermal Anomalies on Europa

    Science.gov (United States)

    Hayne, Paul O.; Christensen, Philip R.; Spencer, John R.; Abramov, Oleg; Howett, Carly; Mellon, Michael; Nimmo, Francis; Piqueux, Sylvain; Rathbun, Julie A.

    2017-10-01

    Endogenic activity is likely on Europa, given its young surface age of and ongoing tidal heating by Jupiter. Temperature is a fundamental signature of activity, as witnessed on Enceladus, where plumes emanate from vents with strongly elevated temperatures. Recent observations suggest the presence of similar water plumes at Europa. Even if plumes are uncommon, resurfacing may produce elevated surface temperatures, perhaps due to near-surface liquid water. Detecting endogenic activity on Europa is one of the primary mission objectives of NASA’s planned Europa Clipper flyby mission.Here, we use a probabilistic model to assess the likelihood of detectable thermal anomalies on the surface of Europa. The Europa Thermal Emission Imaging System (E-THEMIS) investigation is designed to characterize Europa’s thermal behavior and identify any thermal anomalies due to recent or ongoing activity. We define “detectability” on the basis of expected E-THEMIS measurements, which include multi-spectral infrared emission, both day and night.Thermal anomalies on Europa may take a variety of forms, depending on the resurfacing style, frequency, and duration of events: 1) subsurface melting due to hot spots, 2) shear heating on faults, and 3) eruptions of liquid water or warm ice on the surface. We use numerical and analytical models to estimate temperatures for these features. Once activity ceases, lifetimes of thermal anomalies are estimated to be 100 - 1000 yr. On average, Europa’s 10 - 100 Myr surface age implies a resurfacing rate of ~3 - 30 km2/yr. The typical size of resurfacing features determines their frequency of occurrence. For example, if ~100 km2 chaos features dominate recent resurfacing, we expect one event every few years to decades. Smaller features, such as double-ridges, may be active much more frequently. We model each feature type as a statistically independent event, with probabilities weighted by their observed coverage of Europa’s surface. Our results

  15. A Europa no Mundo Entre as Guerras 1919-1939

    OpenAIRE

    Rollo, Maria Fernanda; Ribeiro, Maria Manuela Tavares; Pires, Ana Paula; Cunha, Alice; Valente, Isabel Maria Freitas

    2014-01-01

    O II Encontro A Europa no Mundo é dedicado ao estudo, análise, debate e interpretação das transformações políticas, económicas, sociais e culturais ocorridas na Europa durante o período entre guerras. Os textos compilados neste e-book correspondem a uma parte das comunicações apresentadas no Encontro, reflectem a investigação realizada e procuram constituir um ponto de partida para novas e mais aprofundadas reflexões.

  16. El Consejo de Europa y la abolición total de la pena de muerte en Europa

    OpenAIRE

    Bou Franch, Valentín

    2002-01-01

    1. Introducción.- 2. La parca reglamentación de la pena de muerte.- 3. La superación práctica de una mala disposición.- 3.1 .Por el Tribunal Europeo de Derechos Humanos.- 3.2. Por la práctica de los Estados Miembros del Consejo de Europa.- 3.3. Por la práctica de los órganos del Consejo de Europa.- 4. La abolición de iure de la pena de muerte en Europa.- 4.1. La prohibición de la pena de muerte en tiempo de paz.- 4.2. La abolición de la pena de muerte en todas las circunstancias:- 5. Consider...

  17. Kontrol af konventionelle våben i Europa

    DEFF Research Database (Denmark)

    Hoffmann, Rune; Kierulf, John; Pradhan-Blach, Flemming

    Rapporten indledes med en historisk gennemgang af tilblivelsen og udviklingen af Traktat om Konventionelle Væbnede Styrker i Europa (CFE), som blev iværksat af NATO og det tidligere Warszawapagten i 1973. Traktaten fastsætter et loft for antallet af kampvogne, pansrede kampkøretøjer, artilleripje...

  18. SALTS AND RADIATION PRODUCTS ON THE SURFACE OF EUROPA

    International Nuclear Information System (INIS)

    Brown, M. E.; Hand, K. P.

    2013-01-01

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution ∼40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO 2 . On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO 4 detection on the trailing side with other radiation products, we conclude that MgSO 4 is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl 2 , and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  19. Da Europa faldt i en grav, man selv havde gravet

    DEFF Research Database (Denmark)

    Necef, Mehmet Ümit

    2011-01-01

    Med premierminister Erdogan i spidsen har tyrkiske politikere og intellektuelle tolket Breiviks massakre som udtryk for den generelle islamofobi i Europa. Faktisk fremstilles Breivik ikke som afviger men som mainstream. Dæmoniseringen af den europæiske mentalitet kommer af en tendens til at opfatte...

  20. SALTS AND RADIATION PRODUCTS ON THE SURFACE OF EUROPA

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M. E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Hand, K. P., E-mail: mbrown@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2013-04-15

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution {approx}40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO{sub 2}. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO{sub 4} detection on the trailing side with other radiation products, we conclude that MgSO{sub 4} is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl{sub 2}, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  1. Europa Cinemas auhindas Sõpruse kino / Katrin Rajasaare ; interv. Annika Koppel

    Index Scriptorium Estoniae

    Rajasaare, Katrin

    2005-01-01

    Euroopa ja Vahemere regiooni kinopidajaid ühendav organisatsioon Europa Cinemas kuulutas Sõpruse kino aasta parimaks noorsooürituste korraldamise kategoorias. Oma tööst räägib Sõpruse juht, kes käis ka 18. nov. Budapestis auhinda vastu võtmas

  2. La apatridia y la crisis de refugiados en Europa

    OpenAIRE

    Berényi, Katalin

    2016-01-01

    La Unión Europea debe emitir una directiva sobre estándares comunes para los procedimientos de determinación de la apatridia para así mitigar los impactos particulares de esta condición en el contexto de la continua crisis de refugiados en Europa.

  3. Constraints on Europa's Ocean Composition Imposed by Its Surface Composition

    Science.gov (United States)

    Johnson, P. V.; Hodyss, R. P.; Vu, T. H.; Choukroun, M.

    2017-12-01

    Of the non-terrestrial environments within our Solar System, Europa's global liquid water ocean is arguably the most likely to be habitable. As such, understanding the habitability of Europa's ocean is of great interest to astrobiology and is the focus of missions currently being considered for further exploration of Europa. However, direct analysis of the ocean is unlikely in the foreseeable future. As such, our best means of constraining the subsurface ocean composition and its subsequent habitability currently is by further study of Europa's surface chemical composition. Recently, there has been a body of work published that looks at the chemistry of frozen brines representing putative ocean compositions. Here we take a simplified model of a four ionic component (Na, Mg, SO4, Cl) solution and map out what minerals are formed upon freezing as a function of relative ionic concentration, pH, etc. A `flow-chart' of the freezing sequence was developed based on both published and recently acquired experimental results. In performing this exercise, we are able to begin making meaningful links between observations of the surface chemistry and the chemical environment of the internal ocean.

  4. Modeling Thermal Transport and Surface Deformation on Europa using Realistic Rheologies

    Science.gov (United States)

    Linneman, D.; Lavier, L.; Becker, T. W.; Soderlund, K. M.

    2017-12-01

    Most existing studies of Europa's icy shell model the ice as a Maxwell visco-elastic solid or viscous fluid. However, these approaches do not allow for modeling of localized deformation of the brittle part of the ice shell, which is important for understanding the satellite's evolution and unique geology. Here, we model the shell as a visco-elasto-plastic material, with a brittle Mohr-Coulomb elasto-plastic layer on top of a convective Maxwell viscoelastic layer, to investigate how thermal transport processes relate to the observed deformation and topography on Europa's surface. We use Fast Lagrangian Analysis of Continua (FLAC) code, which employs an explicit time-stepping algorithm to simulate deformation processes in Europa's icy shell. Heat transfer drives surface deformation within the icy shell through convection and tidal dissipation due to its elliptical orbit around Jupiter. We first analyze the visco-elastic behavior of a convecting ice layer and the parameters that govern this behavior. The regime of deformation depends on the magnitude of the stress (diffusion creep at low stresses, grain-size-sensitive creep at intermediate stresses, dislocation creep at high stresses), so we calculate effective viscosity each time step using the constitutive stress-strain equation and a combined flow law that accounts for all types of deformation. Tidal dissipation rate is calculated as a function of the temperature-dependent Maxwell relaxation time and the square of the second invariant of the strain rate averaged over each orbital period. After we initiate convection in the viscoelastic layer by instituting an initial temperature perturbation, we then add an elastoplastic layer on top of the convecting layer and analyze how the brittle ice reacts to stresses from below and any resulting topography. We also take into account shear heating along fractures in the brittle layer. We vary factors such as total shell thickness and minimum viscosity, as these parameters are

  5. Radar attenuation in Europa's ice shell: obstacles and opportunities for constraining shell thickness and thermal structure

    Science.gov (United States)

    Kalousova, Klara; Schroeder, Dustin M.; Soderlund, Krista M.; Sotin, Christophe

    2016-10-01

    With its strikingly young surface and possibly recent endogenic activity, Europa is one of the most exciting bodies within our Solar System and a primary target for spacecraft exploration. Future missions to Europa are expected to carry ice penetrating radar instruments which are powerful tools to investigate the subsurface thermophysical structure of its ice shell.Several authors have addressed the 'penetration depth' of radar sounders at icy moons, however, the concept and calculation of a single value penetration depth is a potentially misleading simplification since it ignores the thermal and attenuation structure complexity of a realistic ice shell. Here we move beyond the concept of a single penetration depth by exploring the variation in two-way radar attenuation for a variety of potential thermal structures of Europa's ice shell as well as for a low loss and high loss temperature-dependent attenuation model. The possibility to detect brines is also investigated.Our results indicate that: (i) for all ice shell thicknesses investigated (5-30 km), a nominal satellite-borne radar sounder will penetrate between 15% and 100% of the total thickness, (ii) the maximum penetration depth strongly varies laterally with the deepest penetration possible through the cold downwellings, (iii) the direct detection of the ice/ocean interface might be possible for shells of up to 15 km if the radar signal travels through the cold downwelling, (iv) even if the ice/ocean interface is not detected, the penetration through most of the shell could constrain the deep shell structure through the loss of signal, and (v) for all plausible ice shells the two-way attenuation to the eutectic point is ≤30 dB which shows a robust potential for longitudinal investigation of the ice shell's shallow structure.Part of this work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. K.K. acknowledges support by the Grant Agency of the

  6. The Influence of Ice-Ocean Interactions on Europa's Overturning Circulation

    Science.gov (United States)

    Zhu, P.; Manucharyan, G. E.; Thompson, A. F.; Goodman, J. C.; Vance, S.

    2016-12-01

    Jupiter's moon Europa appears to have a global liquid ocean, which is located beneath an ice shell that covers the moon's entire surface. Linking ocean dynamics and ice-ocean interactions is crucial to understanding observed surface features on Europa as well as other satellite measurements. Ocean properties and circulation may also provide clues as to whether the moon has the potential to support extraterrestrial life through chemical transport governed by ice-ocean interactions. Previous studies have identified a Hadley cell-like overturning circulation extending from the equator to mid latitudes. However, these model simulations do not consider ice-ocean interactions. In this study, our goal is to investigate how the ocean circulation may be affected by ice. We study two ice-related processes by building idealized models. One process is horizontal convection driven by an equator-to-pole buoyancy difference due to latitudinal ice transport at the ocean surface, which is found to be much weaker than the convective overturning circulation. The second process we consider is the freshwater layer formed by ice melting at the equator. A strong buoyancy contrast between the freshwater layer and the underlying water suppresses convection and turbulent mixing, which may modify the surface heat flux from the ocean to the bottom of the ice. We find that the salinity of the ocean below the freshwater layer tends to be homogeneous both vertically and horizontally with the presence of an overturning circulation. Critical values of circulation strength constrain the freshwater layer depth, and this relationship is sensitive to the average salinity of the ocean. Further coupling of temperature and salinity of the ice and the ocean that includes mutual influences between the surface heat flux and the freshwater layer may provide additional insights into the ice-ocean feedback, and its influence on the latitudinal difference of heat transport.

  7. Lithospheric stresses due to radiogenic heating of an ice-silicate planetary body - Implications for Ganymede's tectonic evolution

    Science.gov (United States)

    Zuber, M. T.; Parmentier, E. M.

    1984-01-01

    Thermal evolution models of differentiated and undifferentiated ice-silicate bodies containing long-lived radiogenic heat sources are examined. Lithospheric sresses arise due to volume change of the interior and temperature change in the lithosphere. For an undifferentiated body, the surface stress peaks early in the evolution, while in the differentiated case, stresses peak later and continue to accumulate for longer periods of time. The variation of near-surface stress with depth shows that stresses for the undifferentiated body initially penetrate to great depths, but rapidly concentrate within a few kilometers of the surface. For the differentiated body, elastic stresses never accumulate at a depth greater than a few kilometers. These models are applied to consider long-term rdioactive heating as a possible mechanism of tectonic activity and bright terrain formation on Ganymede.

  8. An analysis of Jupiter data from the RAE-1 satellite

    Science.gov (United States)

    Carr, T. D.

    1974-01-01

    The analysis of Radio Astronomy Explorer Satellite data are presented. Radio bursts from Jupiter are reported in the frequency range 4700 KHz to 45 KHz. Strong correlations with lo were found at 4700, 3930, and 2200 KHz, while an equally strong Europa effect was observed at 1300, 900, and 700 KHz. Histograms indicating the relative probability and the successful identification of Jupiter activity were plotted, using automatic computer and visual search techniques.

  9. Moons of the solar system from giant Ganymede to dainty Dactyl

    CERN Document Server

    Hall III, James A

    2016-01-01

    This book captures the complex world of planetary moons, which are more diverse than Earth's sole satellite might lead you to believe. New missions continue to find more of these planetary satellites, making an up to date guide more necessary than ever.  Why do Mercury and Venus have no moons at all? Earth's  Moon, of course, is covered in the book with highly detailed maps. Then we move outward to the moons of Mars, then on to many of the more notable asteroid moons, and finally to a list of less-notable ones. All the major moons of the gas giant planets are covered in great detail, while the lesser-known satellites of these worlds are also touched on.  Readers will learn of the remarkable trans-Neptunian Objects – Pluto, Eris, Sedna, Quaoar –including many of those that have been given scant attention in the literature. More than just objects to read about, the planets' satellites provide us with important information about the history of the solar system. Projects to help us learn more abo...

  10. Biomarkers on Europa: Unique signatures produced by radiolysis?

    Science.gov (United States)

    Carlson, R. W.; Hand, K. P.

    A promising habitat for life is Jupiter's moon Europa, with its likely ocean under a young, active surface. Europa orbits in the heart of Jupiter's powerful magnetosphere and suffers intense energetic particle bombardment, producing both good and bad aspects for astrobiology at Europa. Ionizing radiation can produce oxidants that could support a radiation-driven ecology as proposed by Chyba. On the other hand, biomolecular evidence for oceanic life that may be emplaced on the surface is rapidly altered by radiation, perhaps complicating astrobiological searches for evidence of life. We are studying the radiolytic degradation of molecular biomarkers in ice at Europa temperatures by studying both simple organics and more complex biomolecules, including microorganisms. High energy (1-100 keV) electron irradiation is employed and the products are analyzed using infrared spectroscopy, thermal desorption mass spectroscopy, and laser desorption/ionization mass spectroscopy. Hydrocarbon radiolysis yields carbon dioxide and methane which can escape the system and results in the net loss of carbon. Aliphatic molecules with C=O bonds are formed and thought to be mainly polymethylene oxides. When heated, they polymerize to form brown, high-molecular-weight refractory residues with linear, spherical, and ring- shaped macrostructures, typically many tens of micrometers in size. Laser desorption mass spectra of the residues are not overly complex and are different for each initial species. Radiolysis of microorganisms shows the destruction of amine, amide, methyl, and methylene groups, and production of carbon dioxide, carbon monoxide, nitriles, and isocyanates. Mass spectra of irradiated B. pumilus spores are different and surprisingly less complex than those of unirradiated spores. It is possible that unique, diagnostic biosignatures may exist in mass spectra of irradiated microorganisms.

  11. The First USGS Global Geologic Map of Europa

    Science.gov (United States)

    Leonard, E. J.; Patthoff, D. A.; Senske, D.; Collins, G. C.

    2017-12-01

    Understanding the global scale geology of Europa is paramount to gaining insight into the potential habitability of this icy world. To this end, work is ongoing to complete a global geological map at the scale of 1:15 million that incorporates data at all resolutions collected by the Voyager and Galileo missions. The results of this work will aid the Europa Clipper mission, now in formulation, by providing a framework for collaborative and synergistic science investigations. To understand global geologic and tectonic relations, a total of 10 geologic units have been defined. These include: Low Albedo Ridge Material (lam)—low albedo material that irregularly surrounds large (>20 km) ridge structures; Ridged plains (pr)—distributed over all latitudes and characterized by subparallel to cross-cutting ridges and troughs visible at high resolution (material (b)—linear to curvilinear zones with a distinct, abrupt albedo change from the surrounding region; Crater material (c), Continuous Crater Ejecta (ce) and Discontinuous Crater Ejecta (dce)—features associated with impact craters including the site of the impact, crater material, and the fall-out debris respectively; Low Albedo Chaos (chl), Mottled Albedo Chaos (chm) and High Albedo Chaos (chh)—disrupted terrain with a relatively uniform low albedo, patchy/variegated albedo, and uniform high albedo appearance respectively; Knobby Chaos (chk) - disrupted terrain with rough and blocky texture occurring in the high latitudes. In addition to the geologic units, our mapping also includes structural features—Ridges, Cycloids, Undifferentiated Linea, Crater Rims, Depression Margins, Dome Margins and Troughs. We also introduce a point feature (at the global scale), Microchaos, to denote small (material. The completed map will constrain the distribution of different Europa terrains and provide a general stratigraphic framework to assess the geologic history of Europa from the regional to the global scale. Here, we

  12. Comparing the Atmospheric Losses at Io and Europa

    Science.gov (United States)

    Dols, V. J.; Bagenal, F.; Crary, F. J.; Cassidy, T.

    2017-12-01

    At Io and Europa, the interaction of the Jovian plasma with the moon atmosphere leads to a significant loss of atomic/molecular neutrals and ions to space. The processes that lead to atmospheric escape are diverse: atmospheric sputtering, molecular dissociation, molecular ion recombination, Jeans escape etc. Each process leads to neutrals escaping at different velocities (i.e. electron impact dissociation leads to very slow atomic neutrals, sputtering might eject faster molecular neutrals). Some neutrals will be ejected out of the Jovian system; others will form extended neutral clouds along the orbit of the moons. These atomic/molecular extended neutral clouds are probably the main source of plasma for the Jovian magnetosphere. They are difficult to observe directly thus their composition and density are still poorly constrained. A future modeling of the formation of these extended clouds requires an estimate of their atmospheric sources. We estimate the atmospheric losses at Io and Europa for each loss process with a multi-species chemistry model, using a prescribed atmospheric distribution consistent with the observations. We compare the neutral losses at Io and Europa.

  13. PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST /STIS

    International Nuclear Information System (INIS)

    Sparks, W. B.; Bergeron, E.; Cracraft, M.; Deustua, S. E.; Hand, K. P.; McGrath, M. A.

    2016-01-01

    Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude region on Europa: spectroscopic detection of off-limb line emission from the dissociation products of water. Here, we present Hubble Space Telescope direct images of Europa in the far-ultraviolet (FUV) as it transited the smooth face of Jupiter to measure absorption from gas or aerosols beyond the Europa limb. Out of 10 observations, we found 3 in which plume activity could be implicated. Two observations showed statistically significant features at latitudes similar to Roth et al., and the third at a more equatorial location. We consider potential systematic effects that might influence the statistical analysis and create artifacts, and are unable to find any that can definitively explain the features, although there are reasons to be cautious. If the apparent absorption features are real, the magnitude of implied outgassing is similar to that of the Roth et al. feature; however, the apparent activity appears more frequently in our data.

  14. Riding the Banzai Pipeline at Jupiter: Balancing Low Delta-V and Low Radiation to Reach Europa

    Science.gov (United States)

    McElrath, Timothy P.; Campagnola, Stefano; Strange, Nathan J.

    2012-01-01

    Europa's tantalizing allure as a possible haven for life comes cloaked in a myriad of challenges for robotic spacecraft exploration. Not only are the propulsive requirements high and the solar illumination low, but the radiation environment at Jupiter administers its inexorable death sentence on any electronics dispatched to closely examine the satellite. So to the usual trades of mass, delta-V, and cost, we must add radiation dose, which tugs the trajectory solution in a contrary direction. Previous studies have concluded that adding radiation shielding mass is more efficient than using ?V to reduce the exposure time, but that position was recently challenged by a study focusing on delivering simple landers to the Europa surface. During this work, a new trajectory option was found to occupy a strategic location in the delta-V/radiation continuum - we call it the "Banzai pipeline" due to the visual similarity with the end-on view down a breaking wave, as shown in the following figures.

  15. Growth and evolution of satellites in a Jovian massive disc

    Science.gov (United States)

    Moraes, R. A.; Kley, W.; Vieira Neto, E.

    2018-03-01

    The formation of satellite systems in circum-planetary discs is considered to be similar to the formation of rocky planets in a proto-planetary disc, especially super-Earths. Thus, it is possible to use systems with large satellites to test formation theories that are also applicable to extrasolar planets. Furthermore, a better understanding of the origin of satellites might yield important information about the environment near the growing planet during the last stages of planet formation. In this work, we investigate the formation and migration of the Jovian satellites through N-body simulations. We simulated a massive, static, low-viscosity, circum-planetary disc in agreement with the minimum mass sub-nebula model prescriptions for its total mass. In hydrodynamic simulations, we found no signs of gaps, therefore type II migration is not expected. Hence, we used analytic prescriptions for type I migration, eccentricity and inclination damping, and performed N-body simulations with damping forces added. Detailed parameter studies showed that the number of final satellites is strong influenced by the initial distribution of embryos, the disc temperature, and the initial gas density profile. For steeper initial density profiles, it is possible to form systems with multiple satellites in resonance while a flatter profile favours the formation of satellites close to the region of the Galilean satellites. We show that the formation of massive satellites such as Ganymede and Callisto can be achieved for hotter discs with an aspect ratio of H/r ˜ 0.15 for which the ice line was located around 30RJ.

  16. Prime note sulla tutela penale dei culti nei Paesi dell’Est Europa

    Directory of Open Access Journals (Sweden)

    Giovanni Cimbalo

    2011-05-01

    Full Text Available Testo della relazione tenuta al Convegno “La Carta e la Corte” (Ferrara, 27 ottobre 2007 destinata alla pubblicazione negli Atti. SOMMARIO: 1. Alcune considerazioni preliminari sullo status delle Confessioni religiose nei paesi dell’Est Europa - 2. I nuovi orientamenti del diritto penale nell’Est Europa - 3. Le norme statali in materia di tutela penale dei culti e del sentimento religioso. 3. Le norme penali relative ai culti e a al sentimento religioso prima del 1992 nei Paesi dell’Est Europa - 4. Tipologie e tecniche legislative di tutela penale dei culti dopo il 1992 nei Paesi dell’Est Europa - 5. Alcune sommarie considerazioni.

  17. Il Sistema Gateway nello sviluppo della rete del trasporto combinato in Europa: il caso del terminal di Verona Quadrante Europa

    OpenAIRE

    Grossato, Raffaella

    2008-01-01

    Il trasporto intermodale ha acquisito un ruolo sempre più importante nello scenario dei trasporti comunitari merci durante gli ultimi quindici anni. La sfida che si era posta a inizi anni novanta in Europa consisteva nello sviluppo di una rete europea di trasporto combinato strada-ferrovia. A questo fine è stata fondamentale la cooperazione tra gli operatori del settore e le istituzioni (comunitarie e nazionali), nonché l’impulso dato dalla liberalizzazione del trasporto ferrov...

  18. Mapping the Topography of Europa: The Galileo-Clipper Story

    Science.gov (United States)

    Schenk, Paul M.

    2014-11-01

    The renewed effort to return to Europa for global mapping and landing site selection raises the question: What do we know about Europa topography and how do we know it? The question relates to geologic questions of feature formation, to the issue of ice shell thickness, mechanical strength, and internal activity, and to landing hazards. Our topographic data base for Europa is sparse indeed (no global map is possible), but we are not without hope. Two prime methods have been employed in our mapping program are stereo image and shape-from-shading (PC) slope analyses. On Europa, we are fortunate that many PC-DEM areas are also controlled by stereo-DEMs, mitigating the long-wavelength uncertainties in the PC data. Due to the Galileo antenna malfunction, mapping is limited to no more than 20% of the surface, far less than for any of the inner planets. Thirty-seven individual mapping sites have been identified, scattered across the globe, and all have now been mapped. Excellent stereo mapping is possible at all Sun angles, if resolution is below ~350 m. PC mapping is possible at Sun angles greater than ~60 degrees, if emission angles are less than ~40 degrees. The only extended contiguous areas of topographic mapping larger than 150 km across are the two narrow REGMAP mapping mosaics extending pole-to-pole along longitudes 85 and 240 W. These are PC-only and subject to long-wavelength uncertainties and errors, especially in the north/south where oblique imaging produces layover. Key findings include the mean slopes of individual terrain types (Schenk, 2009), topography across chaos (Schenk and Pappalardo, 2004), topography of craters and inferences for ice shell thickness (Schenk, 2002; Schenk and Turtle, 2009), among others. A key discovery, despite the limited data, is that Europan terrains rarely have topographic amplitude greater than 250 meters, but that regionally Europa has imprinted on it topographic amplitudes of +/- 1 km, in the form of raised plateaus and

  19. Modeling the Interaction of Europa with the Jovian Magnetosphere

    Science.gov (United States)

    Rubin, M.; Combi, M. R.; Daldorff, L.; Gombosi, T. I.; Hansen, K. C.; Jia, X.; Kivelson, M. G.; Tenishev, V.

    2011-12-01

    The interaction of Jupiter's corotating magnetosphere with Europa's subsurface water ocean is responsible for the observed induced dipolar magnetic field. Furthermore the pick-up process of newly ionized particles from Europa's neutral atmosphere alters the magnetic and electric field topology around the moon. We use the Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) of the Space Weather Modeling Framework (SWMF) to model the interaction of Europa with the Jovian magnetosphere. The BATS-R-US code solves the governing equations of magnetohydrodynamics (MHD) in a fully 3D adaptive mesh. In our approach we solve the equations for one single ion species, starting from the work by Kabin et al. (J. Geophys. Res., 104, A9, 19983-19992, 1999) accounting for the exospheric mass loading, ion-neutral charge exchange, and ion-electron recombination. We continue by separately solving the electron pressure equation and furthermore extend the magnetic induction equation by the resistive and Hall terms. The resistive term accounts for the finite electron diffusivity and thus allows a more adequate description of the effect of magnetic diffusion due to collisions [Ledvina et al., Sp. Sci. Rev., 139:143-189, 2008]. For this purpose we use ion-electron and electron-neutral collision rates presented by Schunk and Nagy (Ionospheres, Cambridge University Press, 2000). The Hall term allows ions and electrons to move at different velocities while the magnetic field remains frozen to the electrons. The assumed charge neutrality of the ion-electron plasma is maintained everywhere at all times. The model is run at different phases of Jupiter's rotation reflecting the different locations of Europa with respect to the center of the plasma sheet and is compared to measurements obtained by the Galileo magnetometer [Kivelson et al., J. Geophys. Res., 104:4609-4626, 1999]. The resulting influence on the induced magnetic dipolar field is studied and compared to the results from the

  20. Saturn satellites

    International Nuclear Information System (INIS)

    Ruskol, E.L.

    1981-01-01

    The characteristics of the Saturn satellites are discussed. The satellites close to Saturn - Janus, Mimas, Enceladus, Tethys, Dione and Rhea - rotate along the circular orbits. High reflectivity is attributed to them, and the density of the satellites is 1 g/cm 3 . Titan is one of the biggest Saturn satellites. Titan has atmosphere many times more powerful than that of Mars. The Titan atmosphere is a peculiar medium with a unique methane and hydrogen distribution in the whole Solar system. The external satellites - Hyperion, Japetus and Phoebe - are poorly investigated. Neither satellite substance density, nor their composition are known. The experimental data on the Saturn rings obtained on the ''Pioneer-11'' and ''Voyager-1'' satellites are presented [ru

  1. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  2. A New Energy Source for Organic Synthesis in Europa's Surface Ice

    Science.gov (United States)

    Borucki, Jerome G.; Khare, Bishun; Cruikshank, Dale P.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Colored regions on Jupiter's satellite Europa and other icy bodies in the outer Solar System may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with projectiles with V approx. 5 km/s. Part of the projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also releases stress energy as light, heat, electrical, and magnetic fields as secondary emissions. These newly recognized energy sources suggest that the dark material in the area of impact craters are tholins generated from the energy of the impacts and that well up from the fracture zone. Large pools of liquid water would persist under the meteorite crater for thousands of years, with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions.

  3. Trabajo Social y Servicios Sociales en Europa: un paisaje cambiante

    Directory of Open Access Journals (Sweden)

    Susan Lawrence

    2013-12-01

    Full Text Available Este artículo analiza algunas de las diferencias y similitudes, así como las posibles áreas de convergencia, en las políticas de bienestar social, la organización de los Servicios Sociales, las preocupaciones, y la educación y formación de los profesionales sociales en Europa. Se centra especialmente en la Unión Europea como un bloque político dentro de una Europa más amplia, e identifica algunos aspectos de su función en la elaboración de las políticas y prácticas nacionales, incluyendo los ámbitos de la migración y la educación superior. Plantea que las influencias de las tendencias mundiales y regionales de una gran movilidad internacional de la población, conlleva que las profesiones sociales puedan verse cada vez más inmersas en intervenciones «transnacionales» y que, por lo tanto, hayan de ser conscientes de que los sistemas de bienestar y las actuaciones y prácticas profesionales van más allá de las fronteras nacionales. El respeto por la diversidad cultural y el compromiso con la promoción de los derechos humanos y la justicia social, nacional e internacional, se consideran valores esenciales que deben ser compartidos por las profesiones sociales en Europa, y adoptados por los organismos regionales de representación profesional y educativa.

  4. Epidemiología del tabaquismo en Europa

    Directory of Open Access Journals (Sweden)

    Fernández Esteve

    2002-01-01

    Full Text Available El tabaco es la causa de mortalidad prevenible más importante en los países europeos, en los que da cuenta de más de medio millón de muertes anuales. El objetivo de este trabajo es revisar la epidemiología del tabaquismo en Europa, atendiendo a la visión de conjunto sobre el impacto del tabaquismo, a la prevalencia del consumo y a su evolución en la última década, así como revisar otras características relacionadas con la difusión y mantenimiento del tabaquismo: la producción y los precios del tabaco. Treinta de cada 100 europeos adultos fuma cigarrillos a diario. En los países de la Unión Europea se estima que 1 de cada 10 adultos fumadores morirá a causa de los efectos del tabaco, razón que se eleva a 1 de cada 5 en los países del este de Europa. La prevalencia de fumadores desciende entre los hombres adultos en algunos países de la Unión Europea, mientras que aumenta en las mujeres, sobre todo jóvenes, del sur y del este de Europa. Se debe insistir en las medidas para controlar el consumo de tabaco y prevenirlo, tales como la prohibición del consumo en lugares públicos, la prohibición real de la publicidad directa e indirecta, la reducción del cultivo, o el incremento de precios. Estas acciones se deben diseñar, coordinar y desarrollar en y desde los diferentes sectores involucrados en la lucha contra el tabaco, con la participación de redes civiles impulsadas desde los diferentes niveles administrativos (local, regional, nacional con la decisiva participación de organismos y organizaciones supranacionales.

  5. A NOVA EVANGELIZAÇÃO NA EUROPA

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2013-01-01

    Full Text Available Neste estudo, o olhar dirige-se em primeiro lugar para a situação religiosa da Europa. Em seguida, resumiremos o conceito da nova evangelização de acordo com os últimos papas. O passo seguinte será perguntar o que as igrejas podem oferecer à Europa. A nova evangelização deve acontecer no horizonte do ecumenismo e da globalização. Importante ponto de conexão para a transmissão da fé é a constante sede de espiritualidade e de experiência espiritual, bem como de conhecimento da religião e da fé. Por fim, desenvolveremos algumas chances que podem relacionar-se com a nova evangelização na Europa.  ABSTRACT: In this study, the focus is directed first of ali to the religious situation in Europe. Then we will sum up the concept of the new evangelization according to the recent Popes. The next step will be to ask what the churches can offer to Europe. The new evangelization must happen on the horizon of ecumenism and globalization. An important point of connection to the transmission of the faith is the constant thirst for spirituality and spiritual experience as well as the knowledge of religion and faith. Finally, we will develop some opportunities that can relate to the new evangelization in Europe

  6. ¿Hay ahora libertad de prensa en Europa Oriental?

    Directory of Open Access Journals (Sweden)

    Raúl Sorrosa

    2015-01-01

    Full Text Available Con datos de la Freedom House que recibe el 80% de su financiación de parte del gobierno de los Estados Unidos, el articulista expone la situación de la "libertad de información" en los países de Europa Occidental. Habla de lo que fue el fin del comunismo y el control de los medios de comunicación por parte del Estado y de la transformación sufrida luego.

  7. Human Missions to Europa and Titan - Why Not?

    Science.gov (United States)

    Finarelli, Margaret G.

    2004-04-01

    This report describes a long-term development plan to enable human exploration of the outer solar system, with a focus on Europa and Titan. These are two of the most interesting moons of Jupiter and Saturn, respectively, because they are the places in the solar system with the greatest potential for harboring extraterrestrial life. Since human expeditions to these worlds are considered impossible with current capabilities, the proposal of a well-organized sequence of steps towards making this a reality was formulated. The proposed Development Plan, entitled Theseus, is the outcome of a recent multinational study by a group of students in the framework of the Master of Space Studies (MSS) 2004 course at the International Space University (ISU). The Theseus Program includes the necessary development strategies in key scientific and technological areas that are essential for identifying the requirements for the exploration of the outer planetary moons. Some of the topics that are analysed throughout the plan include: scientific observations at Europa and Titan, advanced propulsion and nuclear power systems, in-situ resource utilization, radiation mitigation techniques, closed life support systems, habitation for long-term spaceflight, and artificial gravity. In addition to the scientific and technological aspects of the Theseus Program, it was recognized that before any research and development work may begin, some level of program management must be established. Within this chapter, legal issues, national and international policy, motivation, organization and management, economic considerations, outreach, education, ethics, and social implications are all considered with respect to four possible future scenarios which enable human missions to the outer solar system. The final chapter of the report builds upon the foundations set by Theseus through a case study. This study illustrates how such accomplishments could influence a mission to Europa to search for evidence

  8. Human Missions to Europa and Titan - Why Not?

    Science.gov (United States)

    2004-01-01

    This report describes a long-term development plan to enable human exploration of the outer solar system, with a focus on Europa and Titan. These are two of the most interesting moons of Jupiter and Saturn, respectively, because they are the places in the solar system with the greatest potential for harboring extraterrestrial life. Since human expeditions to these worlds are considered impossible with current capabilities, the proposal of a well-organized sequence of steps towards making this a reality was formulated. The proposed Development Plan, entitled Theseus, is the outcome of a recent multinational study by a group of students in the framework of the Master of Space Studies (MSS) 2004 course at the International Space University (ISU). The Theseus Program includes the necessary development strategies in key scientific and technological areas that are essential for identifying the requirements for the exploration of the outer planetary moons. Some of the topics that are analysed throughout the plan include: scientific observations at Europa and Titan, advanced propulsion and nuclear power systems, in-situ resource utilization, radiation mitigation techniques, closed life support systems, habitation for long-term spaceflight, and artificial gravity. In addition to the scientific and technological aspects of the Theseus Program, it was recognized that before any research and development work may begin, some level of program management must be established. Within this chapter, legal issues, national and international policy, motivation, organization and management, economic considerations, outreach, education, ethics, and social implications are all considered with respect to four possible future scenarios which enable human missions to the outer solar system. The final chapter of the report builds upon the foundations set by Theseus through a case study. This study illustrates how such accomplishments could influence a mission to Europa to search for evidence

  9. Magnetospheric ion sputtering and water ice grain size at Europa

    Science.gov (United States)

    Cassidy, T. A.; Paranicas, C. P.; Shirley, J. H.; Dalton, J. B., III; Teolis, B. D.; Johnson, R. E.; Kamp, L.; Hendrix, A. R.

    2013-03-01

    We present the first calculation of Europa's sputtering (ion erosion) rate as a function of position on Europa's surface. We find a global sputtering rate of 2×1027 H2O s-1, some of which leaves the surface in the form of O2 and H2. The calculated O2 production rate is 1×1026 O2 s-1, H2 production is twice that value. The total sputtering rate (including all species) peaks at the trailing hemisphere apex and decreases to about 1/3rd of the peak value at the leading hemisphere apex. O2 and H2 sputtering, by contrast, is confined almost entirely to the trailing hemisphere. Most sputtering is done by energetic sulfur ions (100s of keV to MeV), but most of the O2 and H2 production is done by cold oxygen ions (temperature ∼ 100 eV, total energy ∼ 500 eV). As a part of the sputtering rate calculation we compared experimental sputtering yields with analytic estimates. We found that the experimental data are well approximated by the expressions of Famá et al. for ions with energies less than 100 keV (Famá, M., Shi, J., Baragiola, R.A., 2008. Sputtering of ice by low-energy ions. Surf. Sci. 602, 156-161), while the expressions from Johnson et al. fit the data best at higher energies (Johnson, R.E., Burger, M.H., Cassidy, T.A., Leblanc, F., Marconi, M., Smyth, W.H., 2009. Composition and Detection of Europa's Sputter-Induced Atmosphere, in: Pappalardo, R.T., McKinnon, W.B., Khurana, K.K. (Eds.), Europa. University of Arizona Press, Tucson.). We compare the calculated sputtering rate with estimates of water ice regolith grain size as estimated from Galileo Near-Infrared Mapping Spectrometer (NIMS) data, and find that they are strongly correlated as previously suggested by Clark et al. (Clark, R.N., Fanale, F.P., Zent, A.P., 1983. Frost grain size metamorphism: Implications for remote sensing of planetary surfaces. Icarus 56, 233-245.). The mechanism responsible for the sputtering rate/grain size link is uncertain. We also report a surface composition estimate using

  10. The ion environment near Europa and its role in surface energetics

    Science.gov (United States)

    Paranicas, C.; Ratliff, J. M.; Mauk, B. H.; Cohen, C.; Johnson, R. E.

    2002-03-01

    This paper gives the composition, energy spectra, and time variability of energetic ions measured just upstream of Europa. From 100 keV to 100 MeV, ion intensities vary by less than a factor of ~5 among Europa passes considered between 1997 and 2000. We use the data to estimate the radiation dose rate into Europa's surface for depths 0.01 mm - 1 m. We find that in a critical fraction of the upper layer on Europa's trailing hemisphere, energetic electrons are the principal agent for radiolysis, and their bremsstrahlung photon products, not included in previous studies, dominate the dose below about 1 m. Because ion bombardment is more uniform across Europa's surface, the radiation dose on the leading hemisphere is dominated by the proton flux. Differences exist between this calculation and published doses based on the E4 wake pass. For instance, proton doses presented here are much greater below 1 mm.

  11. Satellite Communications

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Satellite Communications. Arthur C Clarke wrote a seminal paper in 1945 in wireless world. Use three satellites in geo-synchronous orbit to enable intercontinental communications. System could be realised in '50 to 100 years'

  12. Joint Europa Mission (JEM) : A multi-scale study of Europa to characterize its habitability and search for life.

    Science.gov (United States)

    Blanc, Michel; Prieto Ballesteros, Olga; Andre, Nicolas; Cooper, John F.

    2017-04-01

    Europa is the closest and probably the most promising target to perform a comprehensive characterization of habitability and search for extant life. We propose that NASA and ESA join forces to design an ambitious planetary mission we call JEM (for Joint Europa Mission) to reach this objective. JEM will be assigned the following overarching goal: Understand Europa as a complex system responding to Jupiter system forcing, characterize the habitability of its potential biosphere, and search for life in its surface, sub-surface and exosphere. Our observation strategy to address these goals will combine three scientific measurement sequences: measurements on a high-latitude, low-latitude Europan orbit providing a continuous and global mapping of planetary fields (magnetic and gravity) and of the neutral and charged environment during a period of three months; in-situ measurements at the surface, using a soft lander operating during 35 days, to search for bio-signatures at the surface and sub-surface and operate a geophysical station; measurements of the chemical composition of the very low exosphere and plumes in search for biomolecules. The implementation of these three observation sequences will rest on the combination of two science platforms equipped with the most advanced instrumentation: a soft lander to perform all scientific measurements at the surface and sub-surface at a selected landing site, and a carrier/relay/orbiter to perform the orbital survey and descent sequences. In this concept, the orbiter will perform science operations during the relay phase on a carefully optimized halo orbit of the Europa-Jupiter system before moving to its final Europan orbit. The design of both orbiter and lander instruments will have to accommodate the very challenging radiation mitigation and Planetary Protection issues. The proposed lander science platform is composed of a geophysical station and of two complementary astrobiology facilities dedicated to bio

  13. Microbial habitability of Europa sustained by radioactive sources.

    Science.gov (United States)

    Altair, Thiago; de Avellar, Marcio G B; Rodrigues, Fabio; Galante, Douglas

    2018-01-10

    There is an increasing interest in the icy moons of the Solar System due to their potential habitability and as targets for future exploratory missions, which include astrobiological goals. Several studies have reported new results describing the details of these moons' geological settings; however, there is still a lack of information regarding the deep subsurface environment of the moons. The purpose of this article is to evaluate the microbial habitability of Europa constrained by terrestrial analogue environments and sustained by radioactive energy provided by natural unstable isotopes. The geological scenarios are based on known deep environments on Earth, and the bacterial ecosystem is based on a sulfate-reducing bacterial ecosystem found 2.8 km below the surface in a basin in South Africa. The results show the possibility of maintaining the modeled ecosystem based on the proposed scenarios and provides directions for future models and exploration missions for a more complete evaluation of the habitability of Europa and of icy moons in general.

  14. Topographic variations in chaos on Europa: Implications for diapiric formation

    Science.gov (United States)

    Schenk, Paul M.; Pappalardo, Robert T.

    2004-01-01

    Disrupted terrain, or chaos, on Europa, might have formed through melting of a floating ice shell from a subsurface ocean [Cam et al., 1998; Greenberg et al., 19991, or breakup by diapirs rising from the warm lower portion of the ice shell [Head and Pappalardo, 1999; Collins et al., 20001. Each model makes specific and testable predictions for topographic expression within chaos and relative to surrounding terrains on local and regional scales. High-resolution stereo-controlled photoclinometric topography indicates that chaos topography, including the archetypal Conamara Chaos region, is uneven and commonly higher than surrounding plains by up to 250 m. Elevated and undulating topography is more consistent with diapiric uplift of deep material in a relatively thick ice shell, rather than melt-through and refreezing of regionally or globally thin ice by a subsurface ocean. Vertical and horizontal scales of topographic doming in Conamara Chaos are consistent with a total ice shell thickness >15 km. Contact between Europa's ocean and surface may most likely be indirectly via diapirism or convection.

  15. Seguridad energética rusa: entre Europa y China

    Directory of Open Access Journals (Sweden)

    Antonio Sánchez

    2008-05-01

    Full Text Available Dentro de la seguridad energética rusa aparece como una debilidad importante la concentración de recursos en unos pocos clientes, en concreto en la UE. Por este motivo, las autoridades rusas están tratando de diversificar destinos de venta, tratando de abrir otros mercados, en especial en extremo oriente y, en particular en China. Esto acrecienta su seguridad energética, pero debilita la europea en caso de que la UE no adopte medidas activas. El abastecimiento a Europa desde Rusia, especialmente de gas, depende también de tres grandes limitaciones. En primer lugar, que existan nuevos yacimientos y su posibilidad de movilizarlos conforme aumenten las necesidades europeas. En segundo lugar, aparece el problema del surgimiento de competidores por el gas ruso y, en particular, recientemente se ha subrayado el papel de China como futuro cliente de gas ruso. En tercer lugar, se encuentra la posibilidad de que Rusia pueda ejercer un control especial sobre la oferta de gas mundial, que condicione en cantidad o/y precio el abastecimiento a Europa.

  16. Cross-cutting Relationships of Surface Features on Europa

    Science.gov (United States)

    1997-01-01

    This image of Jupiter's moon Europa shows a very complex terrain of ridges and fractures. The absence of large craters and the low number of small craters indicates that this surface is geologically young. The relative ages of the ridges can be determined by using the principle of cross-cutting relationships; i.e. older features are cross-cut by younger features. Using this principle, planetary geologists are able to unravel the sequence of events in this seemingly chaotic terrain to unfold Europa's unique geologic history.The spacecraft Galileo obtained this image on February 20, 1997. The area covered in this image is approximately 11 miles (18 kilometers) by 8.5 miles (14 kilometers) across, near 15 North, 273 West. North is toward the top of the image, with the sun illuminating from the right.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  17. Big data - modelling of midges in Europa using machine learning techniques and satellite imagery

    DEFF Research Database (Denmark)

    Cuellar, Ana Carolina; Kjær, Lene Jung; Skovgaard, Henrik

    2017-01-01

    coordinates of each trap, start and end dates of trapping. We used 120 environmental predictor variables together with Random Forest machine learning algorithms to predict the overall species distribution (probability of occurrence) and monthly abundance in Europe. We generated maps for every month...... and the Obsoletus group, although abundance was generally higher for a longer period of time for C. imicula than for the Obsoletus group. Using machine learning techniques, we were able to model the spatial distribution in Europe for C. imicola and the Obsoletus group in terms of abundance and suitability...

  18. San Andreas-sized Strike-slip Fault on Europa

    Science.gov (United States)

    1998-01-01

    This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay. In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements. [figure removed for brevity, see original site] The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart. Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above. One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension opens the fault and

  19. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  20. Europa frente a lo extraño

    Directory of Open Access Journals (Sweden)

    Bernhard Waldenfels

    2012-02-01

    Full Text Available "Pensar Europa en sus fronteras", como ya en 1992 proponían un grupo de filósofos de la Universidad de Estrasburgo -Denis Guénoun, Philippe Lacoue-Labarthe, Jean-Luc Nancy, Daniel Payot-, significa considerar qué es eso de la "geofilosofía de Europa" como una cuestión imprescindible que conlleva toda reflexión veraz en torno a la idea de Europa. El debate al que invitaron a una serie diversa de colegas y amigos, procedentes de diferentes naciones, planteaba la posibilidad misma de una identificación de Europa, así como la profundidad, esto es, la misma violencia que esta posibilidad (o imposibilidad conlleva, como los hechos de la más reciente y rabiosa actualidad han confirmado una y otra vez desde aquellas fechas. La propuesta era todo menos fútil. En efecto, como es bien sabido y ellos mismos expresaron unos meses después, en julio de 1993, lo bien cierto es que ha habido terribles furores desencadenados y atroces desgarramientos tanto intra como extraeuropeos, que como mínimo nos urgen a pensar si el proyecto de lo que merece llamarse un 'mundo' puede o no puede confundirse con la exclusiva exportación de aquello que Europa habría inventado, producido e identificado. El futuro parece atenazado por dos figuras mórbidas, dos pesadillas simétricas, la mítica de un planeta homogéneo, como una gigantesca Europa que se extendiera por doquier, y la de una Europa recluida, encerrada en sus imprecisas e inciertas fronteras, una especie de barricadas o trincheras aislantes para que ella devorase en solitario el espejismo de su supuesto bienestar. Esta deplorable alternativa concita parte de nuestras responsabilidades, pues los escenarios del futuro se alimentan necesariamente de formas y de proposiciones de pensamiento, que vale la pena tratar de sopesar y de comprender. A este reto respondió la reflexión del profesor Bernhard Waldenfeis con una memorable intervención, publicada primero en  francés de

  1. Satellite myths

    Science.gov (United States)

    Easton, Roger L.; Hall, David

    2008-01-01

    Richard Corfield's article “Sputnik's legacy” (October 2007 pp23-27) states that the satellite on board the US Vanguard rocket, which exploded during launch on 6 December 1957 two months after Sputnik's successful take-off, was “a hastily put together contraption of wires and circuitry designed only to send a radio signal back to Earth”. In fact, the Vanguard satellite was developed over a period of several years and put together carefully using the best techniques and equipment available at the time - such as transistors from Bell Laboratories/Western Electric. The satellite contained not one but two transmitters, in which the crystal-controlled oscillators had been designed to measure both the temperature of the satellite shell and of the internal package.

  2. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade....... The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites....

  3. Europa's surface radiation environment and considerations for in-situ sampling and biosignature detection

    Science.gov (United States)

    Nordheim, T.; Paranicas, C.; Hand, K. P.

    2017-12-01

    Jupiter's moon Europa is embedded deep within the Jovian magnetosphere and is thus exposed to bombardment by charged particles, from thermal plasma to more energetic particles at radiation belt energies. In particular, energetic charged particles are capable of affecting the uppermost layer of surface material on Europa, in some cases down to depths of several meters (Johnson et al., 2004; Paranicas et al., 2009, 2002). Examples of radiation-induced surface alteration include sputtering, radiolysis and grain sintering; processes that are capable of significantly altering the physical properties of surface material. Radiolysis of surface ices containing sulfur-bearing contaminants from Io has been invoked as a possible explanation for hydrated sulfuric acid detected on Europa's surface (Carlson et al., 2002, 1999) and radiolytic production of oxidants represents a potential source of energy for life that could reside within Europa's sub-surface ocean (Chyba, 2000; Hand et al., 2007; Johnson et al., 2003; Vance et al., 2016). Accurate knowledge of Europa's surface radiation environment is essential to the interpretation of space and Earth-based observations of Europa's surface and exosphere. Furthermore, future landed missions may seek to sample endogenic material emplaced on Europa's surface to investigate its chemical composition and to search for biosignatures contained within. Such material would likely be sampled from the shallow sub-surface, and thus, it becomes crucial to know to which degree this material is expected to have been radiation processed.Here we will present modeling results of energetic electron and proton bombardment of Europa's surface, including interactions between these particles and surface material. In addition, we will present predictions for biosignature destruction at different geographical locations and burial depths and discuss the implications of these results for surface sampling by future missions to Europa's surface.

  4. The Contribution of Io-Raised Tides to Europa's Diurnally-Varying Surface Stresses

    Science.gov (United States)

    Rhoden, Alyssa Rose; Hurford, Terry A,; Manga, Michael

    2011-01-01

    Europa's icy surface records a rich history of geologic activity, Several features appear to be tectonic in origin and may have formed in response to Europa's daily-varying tidal stress [I]. Strike-slip faults and arcuate features called cycloids have both been linked to the patterns of stress change caused by eccentricity and obliquity [2J[3]. In fact, as Europa's obliquity has not been directly measured, observed tectonic patterns arc currently the best indicators of a theoretically supported [4] non-negligible obliquity. The diurnal tidal stress due to eccentricity is calculated by subtracting the average (or static) tidal shape of Europa generated by Jupiter's gravitational field from the instantaneous shape, which varies as Europa moves through its eccentric orbit [5]. In other words, it is the change of shape away from average that generates tidal stress. One might expect tidal contributions from the other large moons of Jupiter to be negligible given their size and the height of the tides they raise on Europa versus Jupiter's mass and the height of the tide it raises on Europa, However, what matters for tidally-induced stress is not how large the lo-raised bulge is compared to the Jupiter-raised bulge but rather the differences bet\\Veen the instantaneous and static bulges in each case. For example, when Europa is at apocenter, Jupiter raises a tide 30m lower than its static tide. At the same time, 10 raises a tide about 0.5m higher than its static tide. Hence, the change in Io's tidal distortion is about 2% of the change in the Jovian distortion when Europa is at apocenter

  5. Tectonic and volcanic evolution of dark terrain and its implications for the internal structure and evolution of Ganymede

    International Nuclear Information System (INIS)

    Murchie, S.L.; Head, J.W.; Plescia, J.B.

    1990-01-01

    Furrows in ancient dark terrain on Ganymede form three systems that are each hemispheric or greater in scale. The oldest of the systems, designated system III, is dominated by approximately concentric troughs centered on about 60 degrees N,50 degrees W. System I, in the anti-Jovian hemisphere, contains concentric and subradial furrows arrayed around a large, degraded palimpsest centered at 15 degrees S,165 degrees W. Furrows in each system formed on and locally are buried by dark volcanic materials that embay and infill preexisting topographic features; they crosscut extremely few well preserved older craters; and they occur on surfaces having significantly different relative crater ages. System II, also in the anti-Jovian hemisphere, contains widely spaced, radially arrayed furrows commonly 500-2000 km in length, which are organized around a large area of dark smooth resurfacing material, intense dark terrain fracturing, and some of the globally oldest light material. Multiple models of the origin of each furrow system were tested using observed geologic features and patterns. Systems I and III were found to be most consistent with reactivation of impact-generated, multiringed structures by endogenic global extension, during a period of widespread dark material volcanism that obliterated a dense, ancient crater population. System II was found to be most consistent with fracturing of a single, circular, isostatic uplift covering an entire hemisphere. On the basis of geologic observations and interpretations and theoretical models of convection in spheres, it is hypothesized that the uplift developed by long-term warming of the upwelling current of a single axisymmetric convection cell in an initially cooler, undifferentiated interior. Such warming would also have created global expansion and supplied the tensional stress inferred to have formed systems I and III

  6. Boomerang Satellites

    Science.gov (United States)

    Hesselbrock, Andrew; Minton, David A.

    2017-10-01

    We recently reported that the orbital architecture of the Martian environment allows for material in orbit around the planet to ``cycle'' between orbiting the planet as a ring, or as coherent satellites. Here we generalize our previous analysis to examine several factors that determine whether satellites accreting at the edge of planetary rings will cycle. In order for the orbiting material to cycle, tidal evolution must decrease the semi-major axis of any accreting satellites. In some systems, the density of the ring/satellite material, the surface mass density of the ring, the tidal parameters of the system, and the rotation rate of the primary body contribute to a competition between resonant ring torques and tidal dissipation that prevent this from occurring, either permanently or temporarily. Analyzing these criteria, we examine various bodies in our solar system (such as Saturn, Uranus, and Eris) to identify systems where cycling may occur. We find that a ring-satellite cycle may give rise to the current Uranian ring-satellite system, and suggest that Miranda may have formed from an early, more massive Uranian ring.

  7. Ion Irradiation of Sulfuric Acid: Implications for its Stability on Europa

    Science.gov (United States)

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

    2010-01-01

    The Galileo near-infrared mapping spectrometer (NIMS) detected regions on Europa's surface containing distorted H2O bands. This distortion likely indicates that there are other molecules mixed with the water ice. Based on spectral comparison, some of the leading possibilities are sulfuric acid, salts. or possibly H3O(+). Previous laboratory studies have shown that sulfuric acid can be created by irradiation of H2OSO2 mixtures, and both molecules are present on Europa. In this project, we were interested in investigating the radiation stability of sulfuric acid (H2SO4) and determining its lifetime on the surface of Europa.

  8. Search for bacterial waste as a possible signature of life on Europa

    International Nuclear Information System (INIS)

    Bhattacherjee, A.B.; Chela-Flores, J.

    2004-07-01

    Observations of the icy Jovian moon Europa by the Galileo spacecraft served to stimulate conceptual planning for missions to Europa to search for signs of life in the volcanically-heated ocean presumed to underlie its thick icy surface. Liquid water is thought to be an essential ingredient for life, so the existence of a second water ocean in the solar system would be of paramount importance in any search for life beyond earth. In-situ measurements will be needed to directly explore the Europan ocean. The wide range of thermal and pressure environments expected on Europa provide a considerable challenge in designing an instrument package. (author)

  9. A deterministic electron, photon, proton and heavy ion transport suite for the study of the Jovian moon Europa

    International Nuclear Information System (INIS)

    Badavi, Francis F.; Blattnig, Steve R.; Atwell, William; Nealy, John E.; Norman, Ryan B.

    2011-01-01

    A Langley research center (LaRC) developed deterministic suite of radiation transport codes describing the propagation of electron, photon, proton and heavy ion in condensed media is used to simulate the exposure from the spectral distribution of the aforementioned particles in the Jovian radiation environment. Based on the measurements by the Galileo probe (1995-2003) heavy ion counter (HIC), the choice of trapped heavy ions is limited to carbon, oxygen and sulfur (COS). The deterministic particle transport suite consists of a coupled electron photon algorithm (CEPTRN) and a coupled light heavy ion algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means to the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, photon, proton and heavy ion exposure assessment in a complex space structure. In this paper, the reference radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron and proton spectra of the Jovian environment as generated by the jet propulsion laboratory (JPL) Galileo interim radiation electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter system mission (EJSM), the JPL provided Europa mission fluence spectrum, is used to produce the corresponding depth dose curve in silicon behind a default aluminum shield of 100 mils (∼0.7 g/cm 2 ). The transport suite can also accept a geometry describing ray traced thickness file from a computer aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point within the interior of the vehicle. In that regard, using a low fidelity CAD model of the Galileo probe generated by the authors, the transport suite was verified versus Monte Carlo (MC) simulation for orbits JOI-J35 of the Galileo probe

  10. The Biological Potential of Mars, the Early Earth, and Europa

    Science.gov (United States)

    Jakosky, B. M.; Shock, E. L.

    1998-09-01

    The potential biomass that could have existed on Mars is constrained by the total amount of energy available to construct it. From an inventory of the available geochemical sources of energy, we estimate that, from the time of the onset of the visible geologic record 4 b.y. ago to the present, as much as 20 g/cm2 of biota could have been constructed. This is the same amount that could have been constructed from similar sources on the early Earth in only 100 m.y. This indicates that there likely was sufficient energy available to support an origin of life on Mars, but not sufficient energy to create a ubiquitous and lush biosphere. Similar calculations for Europa suggest that even less geochemical energy would have been available there.

  11. La familia en Europa y el cambio social

    Directory of Open Access Journals (Sweden)

    JUAN DÍEZ NICOLÁS

    1983-01-01

    Full Text Available Se analizan los cambios experimentados en la estructura familiar y los modelos de vida familiar en los 21 países miembros del Consejo de Europa, usando fuentes variadas. Las tendencias básicas observadas son : descenso del número de matrimonios, incremento de las relaciones prematrimoniales y la cohabitación, matrimonios cada vez más tardíos, incremento de los divorcios, incremento de hogares monoparentales, aumento de los nacimientos ilegítimos, descenso de la natalidad, disminución del número de hijos por matrimonio, concepción más tardía e incremento del tiempo transcurrido entre una concepción y otra., e incremento de los abortos voluntarios.

  12. Galileo's Multiinstrument Spectral View of Europa's Surface Composition

    Science.gov (United States)

    Fanale, F.P.; Granahan, J.C.; McCord, T.B.; Hansen, G.; Hibbitts, C.A.; Carlson, R.; Matson, D.; Ocampo, A.; Kamp, L.; Smythe, W.; Leader, F.; Mehlman, R.; Greeley, R.; Sullivan, R.; Geissler, P.; Barth, C.; Hendrix, A.; Clark, B.; Helfenstein, P.; Veverka, J.; Belton, M.J.S.; Becker, K.; Becker, T.

    1999-01-01

    We have combined spectral reflectance data from the Solid State Imaging (SSI) experiment, the Near-Infrared Mapping Spectrometer (NIMS), and the Ultraviolet Spectrometer (UVS) in an attempt to determine the composition and implied genesis of non-H2O components in the optical surface of Europa. We have considered four terrains: (1) the "dark terrains" on the trailing hemisphere, (2) the "mottled terrain," (3) the linea on the leading hemisphere, and (4) the linea embedded in the dark terrain on the trailing hemisphere. The darker materials in these terrains exhibit remarkably similar spectra in both the visible and near infrared. In the visible, a downturn toward shorter wavelengths has been attributed to sulfur. The broad concentrations of dark material on the trailing hemisphere was originally thought to be indicative of exogenic sulfur implantation. While an exogenic cause is still probable, more recent observations by the UVS team at higher spatial resolution have led to their suggestions that the role of the bombardment may have primarily been to sputter away overlying ice and to reveal underlying endogenic non-H2O contaminants. If so, this might explain why the spectra in all these terrains are so similar despite the fact that the contaminants in the linea are clearly endogenic and those in the mottled terrain are almost certainly so. In the near infrared, all these terrains exhibit much more asymmetrical bands at 1.4 and 2.0 ??m at shorter wavelengths than spectra from elsewhere on Europa. It has been argued that this is because the water molecules are bound in hydrated salts. However, this interpretation has been challenged and it has also been argued that pure coarse ice can exhibit such asymmetric bands under certain conditions. The nature of this controversy is briefly discussed, as are theoretical and experimental studies bearing on this problem. ?? 1999 Academic Press.

  13. UV Spectrophotometry of the Galilean Satellites, Saturnian Satellites & Selected Asteroids

    Science.gov (United States)

    Nelson, Robert M.

    We propose a series of ultraviolet spectral observations of solid surfaces of selected solar system objects, specifically the Galilean satellites of Jupiter, several atmosphereless satellites of Saturn, and the asteroids, 5 Astraea, 18 Melpomene, 532 Herculina, 68 Leto, 31 Euphmsyne, 80 Sappho, 3 Juno, and 39 Laetitia. Historically such spectral observations have allowed for the Identification of spectrally active solid state materials on planetary surfaces. Furthermore, because the rotational properties are known for all the objects proposed for study, this technique will provide a longitude map of such materials on the objects' surfaces. The study of asteroid surface mineralogy is an important method of constraining solar system formation models. The asteroid spectra we have previously acquired with IUE have created unique subdivisions within the existent asteroid types. The new spectra will provide more sophisticated mineralogical characterizations of asteroid surface materials. Our other accomplishments with IUE include mapping of the distribution of condensed S02 on Io, identification of a longitudinal asymmetry on Europa associated with magnetospheric particle bombardment of the surface, and establishing the ultraviolet geometric albedo variation as a function of longitude for all the Galilean satellites. Because Io is the most volcanically active body In the solar system, and short tern variations in selected regions of the Jovian magnetosphere are known to occur, it is important to periodically check for temporal variations in the spectra of the Galilean satellites that may be due to variations n Io tectonic/volcanic activity, or magnetosphere changes. These proposed UV observations are critical to the design and operation of several instruments on Project Galileo, NASA's Jupiter Orbiter and Probe Mission. Spectra of Iapetus, Rhea and Dione have been acquired during the previous year; however, only at orbital locations near elongation. In addition, the dark

  14. Implications of Tidally Driven Convection and Lithospheric Arguments on the Topography of Europa

    Science.gov (United States)

    Sattler-Cassara, L.; Lyra, W.

    2017-11-01

    We present 3D numerical simulations of tidally driven convection in Europa. By associating the resulting normal stress from plumes with surface weakening and resistance from shallower layers, we successfully reproduce domes and double ridges.

  15. Eighth Planta Europa Conference «Save Plants for Earth's Future» (Kiev, Ukraine

    Directory of Open Access Journals (Sweden)

    Alexander N. Tashev

    2017-08-01

    Full Text Available This paper presents information about the Eighth Planta Europa Conference (Save plants for Earth's future (22–26 May 2017, Kiev, Ukraine. We presented brief data on the history of previous Planta Europa meetings. We presented general information about the main events of the Conference, its thematic areas represented by oral and poster presentations. Brief data on the number of participants, presentations and excursions into botanical gardens of Kiev are presented.

  16. The sulfur dilemma: Are there biosignatures on Europa's icy and patchy surface?

    International Nuclear Information System (INIS)

    Chela-Flores, J.

    2006-12-01

    We discuss whether sulphur traces on Jupiter's moon Europa could be of biogenic origin. The compounds detected by the Galileo mission have been conjectured to be endogenic, most likely of cryovolcanic origin, due to their non-uniform distribution in patches. The Galileo space probe first detected the sulphur compounds, as well as revealing that this moon almost certainly has a volcanically heated and potentially habitable ocean hiding beneath a surface layer of ice. In planning future exploration of Europa there are options for sorting out the source of the surficial sulphur. For instance, one possibility is searching for the sulphur source in the context of the study of the Europa Microprobe In Situ Explorer (EMPIE), which has been framed within the Jovian Minisat Explorer Technology Reference Study (ESA). It is conceivable that sulphur may have come from the nearby moon Io, where sulphur and other volcanic elements are abundant. Secondly, volcanic eruptions in Europa's seafloor may have brought sulphur to the surface. Can waste products rising from bacterial colonies beneath the icy surface be a third alternative significant factor in the sulphur patches on the Europan surface? Provided that microorganisms on Europa have the same biochemical pathways as those on Earth, over geologic time it is possible that autochthonous microbes can add substantially to the sulphur deposits on the surface of Europa. We discuss possible interpretations of the non-water-ice elements (especially the sulphur compound mercaptan) in the context of the studies for future missions. To achieve reliable biosignatures it seems essential to go back to Europa. Our work highlights the type of biogenic signatures that can be searched for when probing Europa's icy and patchy surface. (author)

  17. Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures

    Science.gov (United States)

    Jia, Xianzhe; Kivelson, Margaret G.; Khurana, Krishan K.; Kurth, William S.

    2018-05-01

    The icy surface of Jupiter's moon, Europa, is thought to lie on top of a global ocean1-4. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa's surface5,6, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data5-7, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo's closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer8 recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer9 registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter's corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa's thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.

  18. Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures

    Science.gov (United States)

    Jia, Xianzhe; Kivelson, Margaret G.; Khurana, Krishan K.; Kurth, William S.

    2018-06-01

    The icy surface of Jupiter's moon, Europa, is thought to lie on top of a global ocean1-4. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa's surface5,6, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data5-7, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo's closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer8 recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer9 registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter's corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa's thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.

  19. Satellite Radio

    Indian Academy of Sciences (India)

    Satellites have been a highly effective platform for multi- form broadcasts. This has led to a ... diversity offormats, languages, genre, and a universal reach that cannot be met by .... programs can be delivered to whom it is intended. In the case of.

  20. Examining Microbial Survival During Infall onto Europa: An Important Limit on the Origin of Potential European Life

    Science.gov (United States)

    Fries, M.; Conrad, P.; Matney, M.; Steele, A.

    2015-01-01

    Previous work shows that transfer of material from Earth to Europa is statistically possible, opening the question of whether terrestrial biota may have transferred to Europa to populate that world. Transfer of viable organisms is a function of parameters such as ejection shock, radiation exposure, and others, applied across four phases in the transfer process: ejection from the parent body, transport through interplanetary space, infall onto the target world, and biological adaptation. If terrestrial biota could survive transport to Europa, then biology on Europa may be either the product of a separate and unrelated origin or they are the descendants of transferred terrestrial organisms. If, however, transfer of viable organisms is impossible, then any biota present on Europa must be the product of a biological origin independent from terrestrial life. We will investigate the survival likelihood of material falling onto Europa.

  1. Epidemiología del tabaquismo en Europa

    Directory of Open Access Journals (Sweden)

    Esteve Fernández

    2002-01-01

    Full Text Available El tabaco es la causa de mortalidad prevenible más importante en los países europeos, en los que da cuenta de más de medio millón de muertes anuales. El objetivo de este trabajo es revisar la epidemiología del tabaquismo en Europa, atendiendo a la visión de conjunto sobre el impacto del tabaquismo, a la prevalencia del consumo y a su evolución en la última década, así como revisar otras características relacionadas con la difusión y mantenimiento del tabaquismo: la producción y los precios del tabaco. Treinta de cada 100 europeos adultos fuma cigarrillos a diario. En los países de la Unión Europea se estima que 1 de cada 10 adultos fumadores morirá a causa de los efectos del tabaco, razón que se eleva a 1 de cada 5 en los países del este de Europa. La prevalencia de fumadores desciende entre los hombres adultos en algunos países de la Unión Europea, mientras que aumenta en las mujeres, sobre todo jóvenes, del sur y del este de Europa. Se debe insistir en las medidas para controlar el consumo de tabaco y prevenirlo, tales como la prohibición del consumo en lugares públicos, la prohibición real de la publicidad directa e indirecta, la reducción del cultivo, o el incremento de precios. Estas acciones se deben diseñar, coordinar y desarrollar en y desde los diferentes sectores involucrados en la lucha contra el tabaco, con la participación de redes civiles impulsadas desde los diferentes niveles administrativos (local, regional, nacional con la decisiva participación de organismos y organizaciones supranacionales.Tobacco is the most important preventable cause of mortality in European countries, accounting for over half a million deaths per year. A review is presented on the epidemiology of tobacco smoking in Europe, using a comprehensive approach on the health effects of smoking, the prevalence of tobacco consumption, and its evolution in the past decade. Tobacco industry efforts to promote and maintain smoking through

  2. The Plasma Instrument for Magnetic Sounding (PIMS) onboard the Europa Clipper Mission

    Science.gov (United States)

    Westlake, Joseph H.; McNutt, Ralph L.; Kasper, Justin C.; Rymer, Abigail; Case, Anthony; Battista, Corina; Cochrane, Corey; Coren, David; Crew, Alexander; Grey, Matthew; Jia, Xianzhe; Khurana, Krishan; Kim, Cindy; Kivelson, Margaret G.; Korth, Haje; Krupp, Norbert; Paty, Carol; Roussos, Elias; Stevens, Michael; Slavin, James A.; Smith, Howard T.; Saur, Joachim

    2017-10-01

    Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa’s ionosphere affecting the magnetic induction signal. Plasma from Io’s temporally varying torus diffuses outward and mixes with the charged particles in Europa’s own torus producing highly variable plasma conditions. Onboard the Europa Clipper spacecraft the Plasma Instrument for Magnetic Sounding (PIMS) works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa’s subsurface ocean. This investigation exploits currents induced in Europa’s interior by the moon’s exposure to variable magnetic fields in the Jovian system to infer properties of Europa’s subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa’s global liquid ocean by accounting for contributions to the magnetic field from plasma currents.The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. PIMS on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter’s magnetosphere and Europa’s ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa’s magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa’s surface into the atmosphere and

  3. The search for active Europa plumes in Galileo plasma particle detector data: the E12 flyby

    Science.gov (United States)

    Huybrighs, H.; Roussos, E.; Krupp, N.; Fraenz, M.; Futaana, Y.; Barabash, S. V.; Glassmeier, K. H.

    2017-12-01

    Hubble Space Telescope observations of Europa's auroral emissions and transits in front of Jupiter suggest that recurring water vapour plumes originating from Europa's surface might exist. If conclusively proven, the discovery of these plumes would be significant, because Europa's potentially habitable ocean could be studied remotely by taking in-situ samples of these plumes from a flyby mission. The first opportunity to collect in-situ evidence of the plumes will not arise before the early 2030's when ESA's JUICE mission or NASA's Europa Clipper are set to arrive. However, it may be possible that NASA's Galileo mission has already encountered the plumes when it was active in the Jupiter system from 1995 to 2003. It has been suggested that the high plasma densities and anomalous magnetic fields measured during one of the Galileo flybys of Europa (flyby E12) could be connected to plume activity. In the context of the search for Europa plume signatures in Galileo particle data we present an overview of the in-situ plasma particle data obtained by the Galileo spacecraft during the E12 flyby. Focus is in particular on the data obtained with the plasma particle instruments PLS (low energy ions and electrons) and EPD (high energy ions and electrons). We search for signs of an extended exosphere/ionosphere that could be consistent with ongoing plume activity. The PLS data obtained during the E12 flyby show an extended interaction region between Europa and the plasma from Jupiter's magnetosphere, hinting at the existence of an extended ionosphere and exosphere. Furthermore we show how the EPD data are analyzed and modelled in order to evaluate whether a series of energetic ion depletions can be attributed to losses on the moon's surface or its neutral exosphere.

  4. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    noise signal level exceeds 10 times the normal background. EXPERIMENTS FOR SATELLITE ASTRONOMY 615 ANTENNA MONOPOLE -., PREAMPLFE = BANDPASS-FILTER...OUTPUT TO AND DETECTOR TELEMETRYCHANNELS (18) CALIBRATION NOISE MATRIX CLOCK NOISE SOURCE ’ON’ SOURCE COMMAND F ROM PROGRAMERP ANTENNA MONOPOLE FIGURE 13...Animal Tempera- ture Sensing for Studying the Effect of Prolonged Orbital Flight on the Circadian Rhythms of Pocket Mice . Unmanned Spacecraft Meeting

  5. Ciudadanos del este de Europa consumidores de drogas en Barcelona

    Directory of Open Access Journals (Sweden)

    González M.

    2003-01-01

    Full Text Available Desde mayo de 1999 hasta mayo de 2001, hemos contactado en el SAPS (Servicio de Atención Social y Sanitaria de Barcelona con usuarios de drogas de países del este de Europa. Acuden a centros terapéuticos gratuitos, aunque pagan por la organización del viaje unos 500 euros. Son jóvenes entre 18 y 30 años y mantienen el contacto con sus familiares. Conocen los riesgos de transmisión de enfermedades, pero suelen reutilizar las jeringas. Es alta la prevalencia de hepatitis C (92% y B (62% y menor la de infección por el VIH (19%. Si no abandonan las drogas, el retorno es un fracaso y tienen dificultades para proseguir los tratamientos con metadona o antirretrovirales. La respuesta asistencial ha de adecuarse a sus necesidades. Se debe procurar la mediación cultural y la información en los lugares de origen, supervisar los centros terapéuticos y diseñar alternativas a los abandonos. Hay que desarrollar la colaboración internacional, estimular programas de disminución de riesgos derivados del consumo y evitar que del tratamiento se haga un comercio.

  6. Solar satellites

    Energy Technology Data Exchange (ETDEWEB)

    Poher, C.

    1982-01-01

    A reference system design, projected costs, and the functional concepts of a satellite solar power system (SSPS) for converting sunlight falling on solar panels of a satellite in GEO to a multi-GW beam which could be received by a rectenna on earth are outlined. Electricity transmission by microwaves has been demonstrated, and a reference design system for supplying 5 GW dc to earth was devised. The system will use either monocrystalline Si or concentrator GaAs solar cells for energy collection in GEO. Development is still needed to improve the lifespan of the cells. Currently, the cell performance degrades 50 percent in efficiency after 7-8 yr in space. Each SSPS satellite would weigh either 34,000 tons (Si) or 51,000 tons (GaAs), thereby requiring the fabrication of a heavy lift launch vehicle or a single-stage-to-orbit transport in order to minimize launch costs. Costs for the solar panels have been estimated at $500/kW using the GaAs technology, with transport costs for materials to GEO being $40/kg.

  7. Solar satellites

    Science.gov (United States)

    Poher, C.

    A reference system design, projected costs, and the functional concepts of a satellite solar power system (SSPS) for converting sunlight falling on solar panels of a satellite in GEO to a multi-GW beam which could be received by a rectenna on earth are outlined. Electricity transmission by microwaves has been demonstrated, and a reference design system for supplying 5 GW dc to earth was devised. The system will use either monocrystalline Si or concentrator GaAs solar cells for energy collection in GEO. Development is still needed to improve the lifespan of the cells. Currently, the cell performance degrades 50 percent in efficiency after 7-8 yr in space. Each SSPS satellite would weigh either 34,000 tons (Si) or 51,000 tons (GaAs), thereby requiring the fabrication of a heavy lift launch vehicle or a single-stage-to-orbit transport in order to minimize launch costs. Costs for the solar panels have been estimated at $500/kW using the GaAs technology, with transport costs for materials to GEO being $40/kg.

  8. Insert Tidal Here: Finding Stability of Galilean Satellite Interiors

    Science.gov (United States)

    Walker, M.; Bills, B. G.; Mitchell, J.; Rhoden, A.

    2017-12-01

    The tidal environment is often hypothesized as a cause of surface expression in the satellites of the outer solar system. In two notable cases, Io's volcanism is thought to be driven by tidal heating of its mantle while the shattered surface of Europa's ice shell is said to be generated by tidal stresses in that ice. Being adjacent moons of Jupiter, these satellites give us a unique opportunity to apply a single set of general coupled models at each body to predict how one model can predict the heat generation and flow, strain and stress states, and structural parameters for each body. We include the effects of interior evolution into the tidal environment in addition to an evolving orbit. We find that the interiors of Io and Europa will evolve, as a consequence of the heat transfer from interior to surface, and stable structural and heat flow conditions are found. Then as their orbits evolve, perturbed by the mutual interactions of the Laplace mean motion resonance, those conditions of structural and heat stability also change. In particular, we find that at current orbital conditions there is sufficient heat to completely melt Io models for which a convecting interior is capped by a conducting lid. This argues for the presence of a non dissipating (or barely dissipating) core below the mantle, which future Io structure models should include. For the Europa model at current orbit, we use a silicate interior under an ocean capped by a two layer ice; convecting below with a conducting surface. We find stability in heat and structure occurs when the lower ice melts and recedes until the shell is roughly 50km thick. We present a variety of plausible structures for these bodies, and track how the stability of those structures trend as the orbit (in particular the orbital eccentricity, mean motion, and obliquity) change. We show how the Love numbers, layer thicknesses, surface heat flow, and orbital parameters are all linked. For Europa, upcoming measurements from

  9. Precise VLA positions and flux-density measurements of the Jupiter system

    International Nuclear Information System (INIS)

    Muhleman, D.O.; Berge, G.L.; Rudy, D.; Niell, A.E.

    1986-01-01

    VLA C array configuration observations at 2 and 6 cm are presented for Europa, Ganymede, and Callisto at eastern and western elongations with respect to Jupiter, which allowed measurements in right ascension and declination of the satellites with an rms precision of about + or - 0.03 arcsec. The transfer of the mean offsets of Ganymede to Jupiter yields offsets of -0.185 + or - 0.03 arcsec and -0.06 + or - 0.03 arcsec, with respect to JPL-DE-200, at the mean epoch of April 28, 1983; the large offset in right ascension is a combination of the Jupiter ephemeris error and the error in the frame tie of the Jovian planets with the VLBI system of precise positions which was used as the absolute reference frame for the observations. A significant error is noted in the orbital position of Callisto with respect to Ganymede. 12 references

  10. Viscosity of rock-ice mixtures and applications to the evolution of icy satellites

    Science.gov (United States)

    Friedson, A. J.; Stevenson, D. J.

    1983-01-01

    Theory and experiments are used to establish lower and upper bounds on the ratio of actual viscosity to pure ice viscosity for a suspension of rock particles in a water ice matrix. A rheological model for rock-ice mixtures is described, establishing bounds for the range of possible viscosity enhancements provided by a suspension of silicate spheres in an ice matrix. A parametrized thermal convection model is described and used to determine a criterion for criticality, defined as the heat flow and/or silicate volume fraction for which the satellite temperature profile intercepts the melting curve of water ice. The consequences of achieving this critical state are examined, and it is shown that under certain circumstances a 'runaway' differentiation can occur in which the silicates settle to form a core and extensive melting of water ice takes place, the latent heat being supplied by the gravitational energy of differentiation. A possible application of these results to Ganymede and Callisto is described.

  11. KECK II OBSERVATIONS OF HEMISPHERICAL DIFFERENCES IN H2O2 ON EUROPA

    International Nuclear Information System (INIS)

    Hand, K. P.; Brown, M. E.

    2013-01-01

    We present results from Keck II observations of Europa over four consecutive nights using the near-infrared spectrograph. Spectra were collected in the 3.14-4.0 μm range, enabling detection and monitoring of the 3.5 μm feature due to hydrogen peroxide. Galileo Near-Infrared Mapping Spectrometer results first revealed hydrogen peroxide on Europa in the anti-Jovian region of the leading hemisphere at a percent by number abundance of 0.13% ± 0.07% relative to water. We find comparable results for the two nights over which we observed the leading hemisphere. Significantly, we observed a small amount of hydrogen peroxide (∼0.04%) during observations of Europa's anti-Jovian and sub-Jovian hemispheres. Almost no hydrogen peroxide was detected during observations of just the trailing hemisphere. We conclude that the Galileo observations likely represent the maximum hydrogen peroxide concentration, the exception potentially being the cold water ice regions of the poles, which are not readily observable from the ground. Our mapping of the peroxide abundance across Europa requires revisions to previous estimates for Europa's global surface abundance of oxidants and leads to a reduction in the total oxidant delivery expected for the subsurface ocean if an exchange of surface material with the ocean occurs.

  12. Los primeros objetos de bronce en el occidente de Europa

    Directory of Open Access Journals (Sweden)

    Fernández-Miranda, Manuel

    1995-06-01

    Full Text Available The alloy of copper with tin is used to show cultural relations and exchanges between Bronze Age cultures in western and central Europe. At the beginning, the distribution and location of tin resources explains the variations in bronze composition, but interregional ex-change leads later to a more homogeneous alloy. During the Early Bronze Age the Iberian Peninsula was not connected to the exchange networks of western Europe, and the first true bronzes appear at least two centuries la ter. The tin alloy spread over Iberia from north to south, and arrive to South-east at the end of the Middle Brome Age, due to the isolation of this region.

    A través del uso de la aleación de cobre y estaño en la tecnología metalúrgica de la Edad del Bronce europea se analizan las relaciones culturales e intercambios que tienen lugar entre los diversos grupos culturales. Al principio la disponibilidad de recursos minerales de estaño condicionó la composición de la aleación, pero más tarde el establecimiento de relaciones comerciales condujo a una mayor homogeneización en la producción. La Península Ibérica aparece durante el Bronce Antiguo desconectada de las interacciones actuantes en el Occidente de Europa, acusando un retraso en el conocimiento del bronce de al menos dos siglos. La difusión de la aleación se produce de norte a sur, llegando al Sureste a fines del Bronce Medio como consecuencia de su aislamiento.

  13. Robert Musil y los Estados desunificados de Europa

    Directory of Open Access Journals (Sweden)

    Bayón, Fernando

    2006-12-01

    Full Text Available This article is a study of Robert Musil´s work “The Man Without Qualities” from philosophical sources. It is a novel that has produced so many overriding metaphors through which we can better understand the crises of the social identity on the horizont of the last modernity in Europe. Much of the key-concepts that helped in creating the so called “Leyend of Modernity” start to vanish in an irremediable way: not only did Musil trace the disappearance of the support for national aspirations and social cohesion, he also showed us how culture is a mad carrousel of collapsed expectations, and how the prevailing idea of “subjectivity” lacks today any solid or essential nucleus. In the middle of this disenchanted landscape of Europe, where all the modern and clasical illusions became nothing, appears however “a new human being”, since the man “without qualities” is the man with endless possibilities too.El presente ensayo es una interpretación de la novela de Robert Musil “El hombre sin atributos” a partir de fuentes filosóficas. Se trata de una obra que ha producido algunas metáforas decisivas para comprender las crisis de la identidad social en el horizonte de la última modernidad europea. Muchos de los conceptos clave que ayudaron a crear la leyenda de la modernidad empiezan a erosionarse de modo irreversible: se descomponen las aspiraciones nacionales, el sujeto pierde su núcleo sustancial y la cultura es un carrusel de esperanzas abortadas incapaces de responder a ninguna idea rectora. Y, sin embargo, en el paisaje de esta Europa tardomoderna en que se han agotado las pasadas ilusiones surge la idea de que el “hombre sin atributos” es también el “hombre de las posibilidades”.

  14. JUICE space mission to Jupiter

    CERN Document Server

    CERN. Geneva

    2018-01-01

    JUICE - JUpiter ICy moons Explorer - is the first large-class mission in ESA's Cosmic Vision 2015-2025 programme. Planned for launch in 2022 and arrival at Jupiter in 2029, it will spend at least three years making detailed observations of the giant gaseous planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. JUICE will perform detailed investigations of Jupiter and its system in all their inter-relations and complexity with particular emphasis on Ganymede as a planetary body and potential habitat. Investigations of Europa and Callisto would complete a comparative picture of the Galilean moons. Jupiter is the archetype for the giant planets of the Solar System and for the numerous giant planets now known to orbit other stars. Moreover, Jupiter's diverse Galilean satellites - three of which are believed to harbour internal oceans - are central to understanding the habitability of icy worlds. JUICE spacecraft will carry the most powerful remote sensing, geophysical, and in situ paylo...

  15. As valsas na Europa e na América do Sul

    OpenAIRE

    Almeida, Hélder António Moreira de

    2014-01-01

    Dissertação apresentado à Escola Superior de Artes Aplicadas do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Performance. O objetivo deste trabalho é mostrar a história da valsa, a sua origem e influência de países da Europa Ocidental para a Europa do Sul como também a sua exportação Transatlântica para a América do sul. Pretendemos assim, mostrar o interesse destes compositores, na escrita desta forma mu...

  16. The Heat Flux through the Ice Shell on Europa, Constraints from Measurements in Terrestrial Conditions

    Science.gov (United States)

    Hruba, J.; Kletetschka, G.

    2017-12-01

    Heat transport across the ice shell of Europa controls the thermal evolution of its interior. Such process involves energy sources that drive ice resurfacing (1). More importantly, heat flux through the ice shell controls the thickness of the ice (2), that is poorly constrained between 1 km to 30+ km (3). Thin ice would allow ocean water to be affected by radiation from space. Thick ice would limit the heat ocean sources available to the rock-ocean interface at the ocean's bottom due to tidal dissipation and potential radioactive sources. The heat flux structures control the development of geometrical configurations on the Europa's surface like double ridges, ice diapirs, chaos regions because the rheology of ice is temperature dependent (4).Analysis of temperature record of growing ice cover over a pond and water below revealed the importance of solar radiation during the ice growth. If there is no snow cover, a sufficient amount of solar radiation can penetrate through the ice and heat the water below. Due to temperature gradient, there is a heat flux from the water to the ice (Qwi), which may reduce ice growth at the bottom. Details and variables that constrain the heat flux through the ice can be utilized to estimate the ice thickness. We show with this analog analysis provides the forth step towards measurement strategy on the surface of Europa. We identify three types of thermal profiles (5) and fourth with combination of all three mechanisms.References:(1) Barr, A. C., A. P. Showman, 2009, Heat transfer in Europa's icy shell, University of Arizona Press, p. 405-430.(2) Ruiz, J., J. A. Alvarez-Gómez, R. Tejero, and N. Sánchez, 2007, Heat flow and thickness of a convective ice shell on Europa for grain size-dependent rheologies: Icarus, v. 190, p. 145-154.(3) Billings, S. E., S. A. Kattenhorn, 2005, The great thickness debate: Ice shell thickness models for Europa and comparisons with estimates based on flexure at ridges: Icarus, v. 177, p. 397-412.(4) Quick

  17. Trepartsforhandlinger i Danmark og Europa følges ikke ad

    DEFF Research Database (Denmark)

    Mailand, Mikkel

    2016-01-01

    Trepartsforhandlinger med flere emner på dagsordenen flore-rede særligt i 1990’erne og tidligt i 00’erne rundt omkring i Europa, hvor de var fraværende i Danmark. Efter den øko-nomiske krise synes billedet at være vendt.......Trepartsforhandlinger med flere emner på dagsordenen flore-rede særligt i 1990’erne og tidligt i 00’erne rundt omkring i Europa, hvor de var fraværende i Danmark. Efter den øko-nomiske krise synes billedet at være vendt....

  18. Construyendo una nueva Europa. La europeización del modelo de seguridad en Georgia

    OpenAIRE

    Janashvili, Lela; Institut de Ciències Polítiques i Socials. Barcelona, Catalunya

    2014-01-01

    La Estrategia de Seguridad Nacional de cada país se basa en el análisis de los valores, intereses y amenazas contra la seguridad interna y externa. Los intereses de Georgia y Europa con respecto al tema de seguridad coinciden plenamente uno con el otro, según se sostiene en este trabajo. La evolución de los últimos años confirma que es necesario tener grandes dosis de diálogo para construir el sistema de la seguridad europea. Para que Europa tenga una lógica común hay que trabajar para constr...

  19. Televisión regional en la Europa de las Identidades

    Directory of Open Access Journals (Sweden)

    Bernat López

    2015-01-01

    Full Text Available En Europa cerca de trescientos emisoras ahora ofrecen varios servicios comparten una característica peculiar: sirven a pequeños territorios no estatales y/o comunidades étnico-culturales diferenciadas. Comenta de hacia dónde irá la televisión regional en Europa corresponde la palabra "incertidumbre". Tan solo mediante un estrechamiento de la relación con la audiencia y una política abierta e innovadora podrán las televisiones regionales afrontar el futuro con garantías.

  20. Galilean satellite geomorphology

    Science.gov (United States)

    Malin, M. C.

    1983-01-01

    Research on this task consisted of the development and initial application of photometric and photoclinometric models using interactive computer image processing and graphics. New programs were developed to compute viewing and illumination angles for every picture element in a Voyager image using C-matrices and final Voyager ephemerides. These values were then used to transform each pixel to an illumination-oriented coordinate system. An iterative integration routine permits slope displacements to be computed from brightness variations, and correlated in the cross-sun direction, resulting in two dimensional topographic data. Figure 1 shows a 'wire-mesh' view of an impact crater on Ganymede, shown with a 10-fold vertical exaggeration. The crater, about 20 km in diameter, has a central mound and raised interior floor suggestive of viscous relaxation and rebound of the crater's topography. In addition to photoclinometry, the computer models that have been developed permit an examination on non-topographically-derived variations in surface brightness.

  1. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  2. Europas ledere må gøre op med ' folkets vilje

    DEFF Research Database (Denmark)

    Wind, Marlene

    2017-01-01

    Centerleder og professor Marlene Wind insisterer i dagens Politiken i debatindlægget: "Europas ledere må gøre op med ' folkets vilje'", at verdens ledere må stå fast ved de principper, der har været bærende for vores samfund siden anden verdenskrig. Domstolenes politiske uafhængighed, menneskeret...

  3. Salinibater Ruber as a Model for the Habitability of Europa's Ocean

    Science.gov (United States)

    Cardona, M. C.; Ramírez, S. I.

    2017-11-01

    The moon Europa has an ocean enriched with sulfate compounds. This work evaluates the adaptation strategies of Salinibacter ruber, a halophilic bacterium, when subjected to MgSO4 and NaSO4, two of the main salty components of Europás ocean.

  4. Development of a European resource on the origins of pathogens of aquaculture: The Europa Project

    DEFF Research Database (Denmark)

    Snow, M.; Barja, J.; Colquhoun, D.

    2004-01-01

    This workshop described the EUROPA project, an EU-funded program aimed at creating a web-based database of molecular sequence data-sets related to significant pathogens of aquaculture. The project aims to focus the efforts of fish health researchers into generating large, evolving and readily ava...

  5. Necesidad de una política coherente para minerales en Europa. Discusiones y acercamientos actuales

    Directory of Open Access Journals (Sweden)

    Günter Tiess

    2008-03-01

    Full Text Available El artículo resume algunos aspectos relevantes de la política mineral en Europa. Hace un llamado a la Unión Europea para concertar políticas e instrmentos de trabajo que aseguren la disponibilidad de las materias primas esenciales y la sustentabilidad de su extración y su uso.

  6. What does Cassini ENA observations tell us about gas around Europa?

    Science.gov (United States)

    Brandt, Pontus; Mauk, Barry; Westlake, Joseph; Smith, Todd; Mitchell, Donald

    2015-04-01

    From about December 2000 to January 2001 the Ion and Neutral Camera (INCA) imaged Jupiter in Energetic Neutral Atoms (ENA) from a distance of about 137-250 Jovian planetary radii (RJ) over an energy range from about 10 to 300 keV. A forward model is employed to derive column densities and assumes a neutral gas-plasma model and an energetic ion distribution based on Galileo in-situ measurements. We demonstrate that Jupiter observations by INCA are consistent with a column density peaking around Europa's orbit in the range from 2x1012 cm-2 to 7x1012 cm-2, assuming H2, and are consistent with the upper limits reported from the Cassini/UVIS observations. Most of the INCA observations are consistent with a roughly azimuthally symmetric gas distribution, but some appear consistent with an asymmetric gas distribution centred on Europa, which would directly imply that Europa is the source of the gas. Although our neutral gas model assumes a Europa source, we explore other explanations of the INCA observations including: (1) ENAs are produced by charge exchange between energetic ions and neutral hydrogen originating from charge-exchanged protons in the Io plasma torus. However, estimated densities by Cheng (1986) are about one order of magnitude too low to explain the INCA observations; (2) ENAs are produced by charge exchange between energetic ions and plasma ions such as O+ and S+ originating from Io. However, that would require O+ plasma densities higher than expected to compensate for the low charge-exchange cross section between protons and O+; (3) We re-examine the INCA Point-Spread Function (PSF) to determine if the ENA emissions in the vicinity of Europa's orbit could be explained by internal scattering of ENAs originating from Jupiter's high-latitude upper atmosphere. However, the PSF was well constrained by using Jupiter from distances where it could be considered a point source.

  7. Iodine Satellite

    Science.gov (United States)

    Kamhawi, Hani; Dankanich, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Iodine Satellite (iSat) spacecraft will be the first CubeSat to demonstrate high change in velocity from a primary propulsion system by using Hall thruster technology and iodine as a propellant. The mission will demonstrate CubeSat maneuverability, including plane change, altitude change and change in its closest approach to Earth to ensure atmospheric reentry in less than 90 days. The mission is planned for launch in fall 2017. Hall thruster technology is a type of electric propulsion. Electric propulsion uses electricity, typically from solar panels, to accelerate the propellant. Electric propulsion can accelerate propellant to 10 times higher velocities than traditional chemical propulsion systems, which significantly increases fuel efficiency. To enable the success of the propulsion subsystem, iSat will also demonstrate power management and thermal control capabilities well beyond the current state-of-the-art for spacecraft of its size. This technology is a viable primary propulsion system that can be used on small satellites ranging from about 22 pounds (10 kilograms) to more than 1,000 pounds (450 kilograms). iSat's fuel efficiency is ten times greater and its propulsion per volume is 100 times greater than current cold-gas systems and three times better than the same system operating on xenon. iSat's iodine propulsion system consists of a 200 watt (W) Hall thruster, a cathode, a tank to store solid iodine, a power processing unit (PPU) and the feed system to supply the iodine. This propulsion system is based on a 200 W Hall thruster developed by Busek Co. Inc., which was previously flown using xenon as the propellant. Several improvements have been made to the original system to include a compact PPU, targeting greater than 80 percent reduction in mass and volume of conventional PPU designs. The cathode technology is planned to enable heaterless cathode conditioning, significantly increasing total system efficiency. The feed system has been designed to

  8. Good bye, Europa del Este. La desaparición de la Europa de los dos bloques y el difícil camino hacia una nueva identidad en la Europa del Este a través del cine

    Directory of Open Access Journals (Sweden)

    Labrador Ben, Julia María

    2007-08-01

    Full Text Available The Generation of distinguishing marks is described in Europe after the Revolution Of October, the use of the movies in the United States as an element in the Cold War and the European Identity after the fall of the USSR and the Warsaw Pact.Se describe la generación de señas de identidad en Europa tras la revolución de Octubre, la utilización del cine en EEUU como elemento de combate en la guerra fría, y la nueva identidad europea tras la desaparición de la URSS y el Pacto de Varsovia.

  9. Asteroid Satellites

    Science.gov (United States)

    Merline, W. J.

    2001-11-01

    Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other

  10. An evolutionary framework for the Jovian and Saturnian satellites

    International Nuclear Information System (INIS)

    Stevenson, R.J.

    1987-01-01

    The position of the satellite within the protonebula, the influence of the parent planet, particularly the relative effects of tidal (gravitational) as opposed to radiogenic (internal) heat generating processes, as well as the type of ice, exert a control on the evolutionary histories of the Jovian and Saturnian satellites. The landscapes of the moons are modified by surface deformational processes (tectonic activity derived from within the body) and externally derived cratering. The geological history of the Galilean satellites is deduced from surface stratigraphic successions of geological units. Io and Europa, with crater-free surfaces, are tectonically more advanced than crater-saturated Callisto. Two thermal-drive models are proposed based on: an expression for externally derived gravitational influences between two bodies; and internal heat generation via radiogenic decay (expressed by surface area/volume ratio). Both parameters, for the Galilean satellites, are plotted against an inferred product of tectonic processes - the age of the surface terrain. From these diagrams, the tectonic evolutionary state of the more distant Saturnian system are predicted. These moons are fitted into an evolutionary framework for the Solar System. 34 refs.; 4 figs.; 2 tabs

  11. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  12. Benefits to the Europa Clipper Mission Provided by the Space Launch System

    Science.gov (United States)

    Creech, Stephen D.; Patel, Keyur

    2013-01-01

    The National Aeronautics and Space Administration's (NASA's) proposed Europa Clipper mission would provide an unprecedented look at the icy Jovian moon, and investigate its environment to determine the possibility that it hosts life. Focused on exploring the water, chemistry, and energy conditions on the moon, the spacecraft would examine Europa's ocean, ice shell, composition and geology by performing 32 low-altitude flybys of Europa from Jupiter orbit over 2.3 years, allowing detailed investigations of globally distributed regions of Europa. In hopes of expediting the scientific program, mission planners at NASA's Jet Propulsion Laboratory are working with the Space Launch System (SLS) program, managed at Marshall Space Flight Center. Designed to be the most powerful launch vehicle ever flown, SLS is making progress toward delivering a new capability for exploration beyond Earth orbit. The SLS rocket will offer an initial low-Earth-orbit lift capability of 70 metric tons (t) beginning with a first launch in 2017 and will then evolve into a 130 t Block 2 version. While the primary focus of the development of the initial version of SLS is on enabling human exploration missions beyond low Earth orbit using the Orion Multi-Purpose Crew Vehicle, the rocket offers unique benefits to robotic planetary exploration missions, thanks to the high characteristic energy it provides. This paper will provide an overview of both the proposed Europa Clipper mission and the Space Launch System vehicle, and explore options provided to the Europa Clipper mission for a launch within a decade by a 70 t version of SLS with a commercially available 5-meter payload fairing, through comparison with a baseline of current Evolved Expendable Launch Vehicle (EELV) capabilities. Compared to that baseline, a mission to the Jovian system could reduce transit times to less than half, or increase mass to more than double, among other benefits. In addition to these primary benefits, the paper will

  13. Encuesta sobre la construcción política de Europa = Academic survey about constitutionalization of European Union

    OpenAIRE

    Balaguer Callejón, Francisco; Bar Cendón, Antonio; Gil Robles, José María; Linde Paniagua, Enrique; Pérez Calvo, Alberto; Tajadura Tejada, Javier; Balaguer Callejón, Francisco

    2013-01-01

    En esta encuesta un grupo de Catedráticos de Derecho Público responden a preguntas sobre la construcción constitucional de Europa relacionadas con la actual situación del proceso de integración europea, la existencia de un proceso constituyente europeo y de un poder constituyente europeo, a la organización institucional de Europa y a la existencia de un derecho constitucional europeo.Constitutionalization of Europe, European constituent process, European constituent power, European ...

  14. Europa Passage, Hamburg. Pumps ensure thermal comfort at all levels; Die Europa Passage in Hamburg. Pumpen sorgen fuer Komfort auf allen Ebenen

    Energy Technology Data Exchange (ETDEWEB)

    Teders, Klaus

    2009-07-01

    The Europa Passage at Hamburg is a new shopping mall located directly on the Binnenalster river. It was constructed in 2006 and has 30,000 m{sup 2} of shop floor on five levels, which makes it one of Germany's biggest shopping malls. It is frequented every day by up to 40,000 visitors and more than 50,000 visitors on saturdays. In order to ensure optimum comfort even in peak times, the passage is equipped with state-of-the-art technical facilities. Energy-efficient pumps ensure reliable supply of all technical facilities. (orig.)

  15. Analyzing surface features on icy satellites using a new two-layer analogue model

    Science.gov (United States)

    Morales, K. M.; Leonard, E. J.; Pappalardo, R. T.; Yin, A.

    2017-12-01

    The appearance of similar surface morphologies across many icy satellites suggests potentially unified formation mechanisms. Constraining the processes that shape the surfaces of these icy worlds is fundamental to understanding their rheology and thermal evolution—factors that have implications for potential habitability. Analogue models have proven useful for investigating and quantifying surface structure formation on Earth, but have only been sparsely applied to icy bodies. In this study, we employ an innovative two-layer analogue model that simulates a warm, ductile ice layer overlain by brittle surface ice on satellites such as Europa and Enceladus. The top, brittle layer is composed of fine-grained sand while the ductile, lower viscosity layer is made of putty. These materials were chosen because they scale up reasonably to the conditions on Europa and Enceladus. Using this analogue model, we investigate the role of the ductile layer in forming contractional structures (e.g. folds) that would compensate for the over-abundance of extensional features observed on icy satellites. We do this by simulating different compressional scenarios in the analogue model and analyzing whether the resulting features resemble those on icy bodies. If the resulting structures are similar, then the model can be used to quantify the deformation by calculating strain. These values can then be scaled up to Europa or Enceladus and used to quantity the observed surface morphologies and the amount of extensional strain accommodated by certain features. This presentation will focus on the resulting surface morphologies and the calculated strain values from several analogue experiments. The methods and findings from this work can then be expanded and used to study other icy bodies, such as Triton, Miranda, Ariel, and Pluto.

  16. BOOK REVIEW: Geheimnisvolles Universum - Europas Astronomen entschleiern das Weltall

    Science.gov (United States)

    Duerbeck, H. W.; Lorenzen, D. H.

    2002-12-01

    The 25th birthday of ESO, in 1987, was celebrated by the publication of an illustrated popular book, "Exploring the Southern Sky" (Springer-Verlag 1987), which also saw editions in Danish, English, French, German, and Spanish. Written and illustrated by the ESO staff members Svend Laustsen, Claus Madsen and Richard M. West, its many pictures were mainly taken with the ESO 3.6m and Schmidt telescopes. The structure of the book - perhaps at that time somewhat unusual - started with things far away (Universe and galaxies), zoomed in to the Milky Way, and finally reached the Solar System (with a concluding chapter dealing with the La Silla observatory). Now, with the 4 units of the Very Large Telescope in full operation, and on the occasion of ESO's 40th birthday, another jubilee book has appeared: "Geheimnisvolles Universum: Europas Astronomen entschleiern das Weltall", written by the science journalist Dirk H. Lorenzen, of Hamburg, Germany, and prefaced by Catherine Cesarsky, Director General of ESO. Presumably, this book will also soon become available in more languages spoken in ESO member countries. Thus it may be worthwhile to review the first edition, although some readers may like to wait for more easily accessible editions. Before going into details, let me first mention that I find this a very impressing book, great to look at and refreshing to read. With ESO seen through the eyes of a visitor, things gain a perspective that is quite different from that of the previous book, and at least as attractive. It comes as no surprise that the book starts with a visit of ESO's showcase, the Paranal Observatory, and the writer not only notes down his own impressions, but also cites statements of some of the many people that keep Paranal going - technicians and staff astronomers. This mixture of texts provides a good impression of the operations at a large observatory for the general reader. The two more 'astronomical' parts that follow deal with star and planet

  17. Poderes probatorios de las partes y del juez en Europa

    Directory of Open Access Journals (Sweden)

    Michele Taruffo

    2006-01-01

    Full Text Available El artículo desmenuza con fuerza argumental, de fuentes, histórica y con pleno conocimiento del derecho procesal civil comparado los distintos postulados políticos, ideológicos y meta jurídicos contra el poder probatorio del juez en el proceso. Para el autor tres son los sistemas existentes en materia de actividad probatoria del juez en Europa: todos - en más o en menos - admiten la actividad probatoria de oficio por el juez. La conclusión es lapidaria: el asiento liberal de los críticos a esta realidad no es ni coherente ni preciso y que refieren al liberalismo del siglo XIX en los que estuvo vigente las concepciones del proceso civil típico del individualismo propietario. Consideraciones generales de este género serían probablemente suficientes para demostrar que las ecuaciones del tipo «poderes de instrucción del juez = régimen autoritario» y «juez pasivo = régimen liberal» son vagas y genéricas, y se reducen a slogans polémicos faltos de valor científico. Ello es, resulta un sofisma el "juez activo autoritario versus juez pasivo liberal". Existen así numerosos sistemas demócratas en los que el juez cuenta con amplios poderes de instrucción, como ocurre p.e. en Francia, en Suiza y en Alemania. En sustancia, cada decisión no es «buena» sólo porque pone punto final al conflicto; la decisión es «buena» si pone punto final al conflicto siendo fundada en criterios legales y racionales, entre los que asume importancia particular la veracidad de la comprobación de los hechos. Si se piensa en un «buen» juez, capaz de ejercer correctamente y racionalmente sus poderes, no hay razón de temer que él se vuelva parcial, e incapaz de valorar las pruebas, por el sólo hecho de haber dispuesto o sugerido su adquisición. Sólo si se piensa en un juez incapaz y psíquicamente débil se puede temer que él pierda su propia imparcialidadThe article treats different political and ideological and the meta judicial postulates

  18. Satellite image collection optimization

    Science.gov (United States)

    Martin, William

    2002-09-01

    Imaging satellite systems represent a high capital cost. Optimizing the collection of images is critical for both satisfying customer orders and building a sustainable satellite operations business. We describe the functions of an operational, multivariable, time dynamic optimization system that maximizes the daily collection of satellite images. A graphical user interface allows the operator to quickly see the results of what if adjustments to an image collection plan. Used for both long range planning and daily collection scheduling of Space Imaging's IKONOS satellite, the satellite control and tasking (SCT) software allows collection commands to be altered up to 10 min before upload to the satellite.

  19. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  20. Large Binocular Telescope Observations of Europa Occulting Io's Volcanoes at 4.8 μm

    Science.gov (United States)

    Skrutskie, Michael F.; Conrad, Albert; Resnick, Aaron; Leisenring, Jarron; Hinz, Phil; de Pater, Imke; de Kleer, Katherine; Spencer, John; Skemer, Andrew; Woodward, Charles E.; Davies, Ashley Gerard; Defrére, Denis

    2015-11-01

    On 8 March 2015 Europa passed nearly centrally in front of Io. The Large Binocular Telescope observed this event in dual-aperture AO-corrected Fizeau interferometric imaging mode using the mid-infrared imager LMIRcam operating behind the Large Binocular Telescope Interferometer (LBTI) at a broadband wavelength of 4.8 μm (M-band). Occultation light curves generated from frames recorded every 123 milliseconds show that both Loki and Pele/Pillan were well resolved. Europa's center shifted by 2 kilometers relative to Io from frame-to-frame. The derived light curve for Loki is consistent with the double-lobed structure reported by Conrad et al. (2015) using direct interferometric imaging with LBTI.

  1. Ethical, social and public awareness issues in gene therapy EuropaBio.

    Science.gov (United States)

    2002-01-01

    EuropaBio, the European Association for Bio-industries, represents 40 corporate members operating world wide and 14 national associations (totaling up to 700 small- and medium-sized enterprises) involved in research, development, testing, manufacturing, sales, and distribution of biotechnology-derived products and services in the field of health cae, agriculture, food, and the environment. AGE is a group of researchers and university professors involved in high-level professional activities related to bioethics, and particularly interested in ethical issues related to the development and use of modern technology. It is essential that industry actively participates in, and contributes to, the social debate on emerging technologies. Therefore, EuropaBio presents herein its view on gene therapy and its responsible development and use.

  2. Biomass gasification in Europe - status and perspectives; Vergasung von Biomasse in Europa - Stand und Perspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Dinkelbach, L.; Kaltschmitt, M. [Stuttgart Univ. (Germany). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER)

    1996-12-31

    Gasification of biomass is a promising option, especially in the fields of waste management and power generation, but there are considerable economic and technical problems that must be solved first. A critical analysis of biomass gasification in Europe today shows that this technology is not marketable today and cannot contribute to environmentally acceptable power supply on a short-term basis. (orig) [Deutsch] Von allen Moeglichkeiten einer energetischen Nutzung von Biomasse stellt die Technik der Vergasung insbesondere in den Bereichen Abfallentsorgung und Stromerzeugung eine vielversprechende Option dar. Einer weiteren Verbreitung dieser Technik stehen allerdings erhebliche wirtschaftliche und technische Probleme entgegen. Die kritische Analyse der derzeitigen Gegebenheiten der Biomassevergasung in Europa fuehrt zu dem Schluss, dass diese Technik noch nicht unmittelbar vor der Mrkteinfuehrung steht und somit kurzfristig keinen merklichen Beitrag zu einer umwelt- und klimavertraeglicheren Energieversorgung in Europa leisten kann. (orig)

  3. The influence of meridional ice transport on Europa's ocean stratification and heat content

    Science.gov (United States)

    Zhu, P.; Manucharyan, G.; Thompson, A. F.; Goodman, J. C.; Vance, S.

    2017-12-01

    Jupiter's moon Europa likely hosts a saltwater ocean beneath its icy surface. Geothermal heating and rotating convection in the ocean may drive a global overturning circulation that redistributes heat vertically and meridionally, preferentially warming the ice shell at the equator. Here we assess thepreviously unconstrained influence of ocean-ice coupling on Europa's ocean stratification and heat transport. We demonstrate that a relatively fresh layer can form at the ice-ocean interface due to a meridional ice transport forced by the differential ice shell heating between the equator and the poles. We provide analytical and numerical solutions for the layer's characteristics, highlighting their sensitivity to critical ocean parameters. For a weakly turbulent and highly saline ocean, a strong buoyancy gradient at the base of the freshwater layer can suppress vertical tracer exchange with the deeper ocean. As a result, the freshwater layer permits relatively warm deep ocean temperatures.

  4. Biomass gasification in Europe - status and perspectives; Vergasung von Biomasse in Europa - Stand und Perspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Dinkelbach, L; Kaltschmitt, M [Stuttgart Univ. (Germany). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER)

    1997-12-31

    Gasification of biomass is a promising option, especially in the fields of waste management and power generation, but there are considerable economic and technical problems that must be solved first. A critical analysis of biomass gasification in Europe today shows that this technology is not marketable today and cannot contribute to environmentally acceptable power supply on a short-term basis. (orig) [Deutsch] Von allen Moeglichkeiten einer energetischen Nutzung von Biomasse stellt die Technik der Vergasung insbesondere in den Bereichen Abfallentsorgung und Stromerzeugung eine vielversprechende Option dar. Einer weiteren Verbreitung dieser Technik stehen allerdings erhebliche wirtschaftliche und technische Probleme entgegen. Die kritische Analyse der derzeitigen Gegebenheiten der Biomassevergasung in Europa fuehrt zu dem Schluss, dass diese Technik noch nicht unmittelbar vor der Mrkteinfuehrung steht und somit kurzfristig keinen merklichen Beitrag zu einer umwelt- und klimavertraeglicheren Energieversorgung in Europa leisten kann. (orig)

  5. ALMA Thermal Observations of a Proposed Plume Source Region on Europa

    Energy Technology Data Exchange (ETDEWEB)

    Trumbo, Samantha K.; Brown, Michael E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Butler, Bryan J. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

    2017-10-01

    We present a daytime thermal image of Europa taken with the Atacama Large Millimeter Array. The imaged region includes the area northwest of Pwyll Crater, which is associated with a nighttime thermal excess seen by the Galileo Photopolarimeter Radiometer and with two potential plume detections. We develop a global thermal model of Europa and simulate both the daytime and nighttime thermal emission to determine if the nighttime thermal anomaly is caused by excess endogenic heat flow, as might be expected from a plume source region. We find that the nighttime and daytime brightness temperatures near Pwyll Crater cannot be matched by including excess heat flow at that location. Rather, we can successfully model both measurements by increasing the local thermal inertia of the surface.

  6. La dimensión intercomprensiva en el aprendizaje de lenguas extranjeras en Europa

    OpenAIRE

    Vez, José Manuel

    2004-01-01

    Para la comunidad de naciones que formamos Europa, unido no significa uniforme. La riqueza, la diversidad y la originalidad de sus culturas representan su propia fuerza y las condiciones de respeto que pueden hacer valer antes los demás. No hay duda que la clave de vitalidad de una cultura es su lengua, lo que supone, a escala de todo un gran continente, la existencia de un plurilingüismo real, es decir vivo y militante.

  7. Science Goals, Objectives, and Investigations of the 2016 Europa Lander Science Definition Team Report

    Science.gov (United States)

    Hand, Kevin P.; Murray, Alison; Garvin, James; and the Europa Lander Science Definition Team, Project Science Team, and Project Engineering Team.

    2017-10-01

    In June of 2016 NASA convened a 21-person team of scientists to establish the science goals, objectives, investigations, measurement requirements, and model payload of a Europa lander mission concept. The NASA HQ Charter goals, in priority order, are as follows:1) Search for evidence of life on Europa, 2) Assess the habitability of Europa via in situ techniques uniquely available to a lander mission, 3) Characterize surface and subsurface properties at the scale of the lander to support future exploration of Europa.Within Goal 1, four Objectives were developed for seeking signs of life. These include the need to: a) detect and characterize any organic indicators of past or present life, b) identify and characterize morphological, textural, and other indicators of life, c) detect and characterize any inorganic indicators of past or present life, and d) determine the provenance of Lander-sampled material. Goal 2 focuses on Europa’s habitability and ensures that even in the absence of the detection of any potential biosignatures, significant ocean world science is still achieved. Goal 3 ensures that the landing site region is quantitatively characterized in the context needed for Goals 1 and 2, and that key measurements about Europa’s ice shell are made to enable future exploration.Critically, scientific success cannot be, and should never be, contingent on finding signs of life - such criteria would be levying requirements on how the universe works. Rather, scientific success is defined here as achieving a suite of measurements such that if convincing signs of life are present on Europa’s surface they could be detected at levels comparable to those found in benchmark environments on Earth, and, further, that even if no potential biosignatures are detected, the science return of the mission will significantly advance our fundamental understanding of Europa’s chemistry, geology, geophysics, and habitability.

  8. Seismic signal and noise on Europa and how to use it

    Science.gov (United States)

    Panning, M. P.; Stähler, S. C.; Bills, B. G.; Castillo, J.; Huang, H. H.; Husker, A. L.; Kedar, S.; Lorenz, R. D.; Pike, W. T.; Schmerr, N. C.; Tsai, V. C.; Vance, S.

    2017-12-01

    Seismology is one of our best tools for detailing interior structure of planetary bodies, and a seismometer is included in the baseline and threshold mission design for a potential Europa lander mission. Guiding mission design and planning for adequate science return, though, requires modeling of both the anticipated signal and noise. Assuming ice seismicity on Europa behaves according to statistical properties observed in Earth catalogs and scaling cumulative seismic moment release to the moon, we simulate long seismic records and estimate background noise and peak signal amplitudes (Panning et al., 2017). This suggests a sensitive instrument comparable to many broadband terrestrial instruments or the SP instrument from the InSight mission to Mars will be able to record signals, while high frequency geophones are likely inadequate. We extend this analysis to also begin incorporation of spatial and temporal variation due to the tidal cycle, which can help inform landing site selection. We also begin exploration of how chaotic terrane at the bottom of the ice shell and inter-ice heterogeneities (i.e. internal melt structures) may affect predicted seismic observations using 2D numerical seismic simulations. We also show some of the key seismic observations to determine interior properties of Europa (Stähler et al., 2017). M. P. Panning, S. C. Stähler, H.-H. Huang, S. D. Vance, S. Kedar, V. C. Tsai, W. T. Pike, R. D. Lorenz, "Expected seismicity and the seismic noise environment of Europa," J. Geophys. Res., in revision, 2017. S. C. Stähler, M. P. Panning, S. D. Vance, R. D. Lorenz, M. van Driel, T. Nissen-Meyer, S. Kedar, "Seismic wave propagation in icy ocean worlds," J. Geophys. Res., in revision, 2017.

  9. Da TV pública europeia à "alienação" da Ideia de Europa

    Directory of Open Access Journals (Sweden)

    Francisco Rui Cádima

    Full Text Available Resumo As políticas europeias, em matéria de televisão pública e de produção audiovisual têm sido, de um modo geral, muito negativas para a experiência cultural europeia, e para a identidade e o reforço da Ideia de Europa. Ao fim de mais de 30 anos de políticas hesitantes e precárias que têm vindo sistematicamente a diminuir a esfera de ação cultural e a identidade europeia do audiovisual público dos Estados-membros da UE, estamos provavelmente a chegar a um ponto de não retorno, em plena fase de transição para o digital. No atual contexto político de revisão da Diretiva do audiovisual, ou essas políticas reforçam a competência das televisões públicas europeias para a construção da Ideia de Europa, ou será a própria Europa e os meios audiovisuais de difusão da sua cultura que entrarão definitivamente em perigo.

  10. Expected Recovery of Europa's Geophysical Attributes with Clipper Gravity Science Investigation

    Science.gov (United States)

    Verma, Ashok Kumar; Margot, Jean-Luc

    2017-10-01

    The primary gravity science objective of NASA’s Clipper mission to Europa is to confirm the presence or absence of a global subsurface ocean beneath Europa's icy crust. Gravity field measurements obtained with a radio science investigation can reveal much about Europa's interior structure. Here, we conduct extensive simulations of the radio science measurements with the anticipated spacecraft trajectory and attitude (17F12V2) and assets on the spacecraft and the ground, including antenna orientations and beam patterns, transmitter characteristics, and receiver noise figures. In addition to two-way Doppler measurements, we also include radar altimeter crossover range measurements. We concentrate on +/-2 hour intervals centered on the closest approach of each one of the 46 flybys. Our covariance analyses reveal the precision with which the tidal Love number k2, second-degree gravity coefficients C20 and C22, and higher-order gravity coefficients can be determined. The results depend strongly on the Deep Space Network (DSN) assets that are deployed to track the spacecraft. We find that some DSN allocations are sufficient to conclusively confirm the presence or absence of a global ocean and to evaluate whether the ice shell is hydrostatic.

  11. Jovian longitudinal asymmetry in Io-related and Europa-related auroral hot spots

    International Nuclear Information System (INIS)

    Dessler, A.J.; Chamberlain, J.W.

    1979-01-01

    Jupiter's internal magnetic field is markedly non-dipolar. We propose that Io- or Europa-generated auroral emissions (originating at the foot of either Io's or Europa's magnetic flux tube) are largely restricted to longitudes where Jupiter's ionospheric conductivity is enhanced. Trapped, energetic electrons that drift into Jupiter's atmosphere, in regions where the Jovian magnetic field is anomalously weak, produce the increased conductivity. The longitude range of enchanced auroral hot-spot emissions is thus restricted to an active sector that is determined from dekametric radio emission to lie in the northern hemisphere in the Jovian System III (1965) longitude range of 205 0 +- 30 0 . Relatively weaker auroral hot spots should occur in the southern hemisphere along the mgnetic conjugate trace covering the longitude range of 215 0 +- 55 0 . At other longitudes, the brightness of the hot spot should decrease by at least one order of magnitude. These results, with respect to both brightness and longitude, are in accord with the observations of Jovian auroral hot spots reported by Atreya et al. We show that the northern hemisphere foot of either Io's or Europa's magnetic flux tube was in the preferred longitude range (the active sector) at the time of each observation

  12. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  13. Foundational Data Products for Europa: A Planetary Spatial Data Infrastructure Example

    Science.gov (United States)

    Archinal, B. A.; Laura, J.; Becker, T. L.; Bland, M. T.; Kirk, R. L.

    2017-12-01

    Any Spatial Data Infrastructure (SDI), including a Planetary SDI (PSDI [1]), includes primary components such as "policy, access network, technical standards, people (including partnerships), and data" [2]. Data is largely categorized into critical foundational products and framework data products. Of data themes [3] previously identified for the U. S. National SDI, we identify [4] three types of products that are foundational to a PSDI: geodetic coordinate reference systems, elevation information, and orthomosaics. We previously listed examples of such products for the Moon (ibid.). Here, we list the current state of these three foundational products for Europa, a key destination in the outer Solar System. Geodetic coordinate reference systems for Europa are based on photogrammetric control networks generated from processing of Voyager and Galileo images, the most recent being that created by M. Davies and T. Colvin at The RAND Corporation in the late 1990s. The Voyager and Galileo images provide insufficient stereo coverage to derive a detailed global topographic model, but various global ellipsoidal shape models have been derived using e.g. the RAND network or limb profile data. The best-known global mosaic of Europa is a controlled orthomosaic produced by the U.S. Geological Survey [5], based on the RAND network and triaxial ellipsoid shape model. Near future needs include comparing the resolution and accuracy of these products with estimates for newer products that might supersede them, including released or unreleased regional products (such as digital terrain models or mosaics) and products that could be made by processing of extant data. Understanding these PSDI fundamental needs will also improve assessing and prioritizing products that are planned for by the upcoming NASA Europa Clipper mission. This effort is not only useful for Europa science, but is also a first step toward developing such summaries for all Solar System bodies with relevant data, which

  14. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    Science.gov (United States)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    In 1995, the Galileo spacecraft arrived at Jupiter to conduct follow-up experiments on pathfinder Pioneer and key Voyager discoveries especially at Io, Europa, Ganymede and Callisto. These new observations helped expand our scientific knowledge of the prominent Galilean satellites; studies revealed diversity with respect to their geology, internal structure, evolution and degree of past and present activity. Jupiter's diverse Galilean satellites, of which three are believed to harbor internal oceans, are central to understanding the habitability of icy worlds. Galileo provided for the first time compelling evidence of a near-surface global ocean on Europa. Furthermore, by understanding the Jupiter system and unraveling the history of its evolution from initial formation to the emergence of possible habitats and life, gives insight into how giant planets and their satellite systems form and evolve. Most important, new light is shed on the potential for the emergence and existence of life in icy satellite oceans. In 2009, NASA released a detailed Jupiter Europa Mission Study (EJSM) that proposed an ambitious Flagship Mission to understand more fully the satellites Europa and Ganymede within the context of the Jovian system. Key to EJSM is the NASA led Jupiter Europa Orbiter (JEO) and the ESA led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute a choreographed exploration of the Jovian system before settling into orbit around Europa and Ganymede, respectively. The National Academies Planetary Decadal Survey, 2011 has listed the NASA-led JEO as the second highest priority mission for the decade 2013-2022, and if chosen it would be launched in 2020 with arrival at Jupiter in 2025. If the JEO mission is not chosen it is anticipated that there will be opportunities in future decadal cycles. Jupiter Orbit Insertion (JOI) begins a 30-month Jovian system tour followed by nine months of science mapping after Europa Orbit Insertion (EOI) in July 2028. The orbiter will

  15. Static and kinematic positioning using WADGPS from geostationary satellites

    Science.gov (United States)

    Cefalo, R.; Gatti, M.

    2003-04-01

    STATIC AND KINEMATIC POSITIONING USING WADGPS CORRECTIONS FROM GEOSTATIONARY SATELLITES Cefalo R. (1), Gatti M (2) (1) Department of Civil Engineering, University of Trieste, P.le Europa 1, 34127 Trieste, Italy, cefalo@dic.univ.trieste.it, (2) Department of Engineering, University of Ferrara, via Saragat 1, 44100 Ferrara, Italy, mgatti@ing.unife.it ABSTRACT. Starting from February 2000, static and kinematic experiments have been performed at the Department of Civil Engineering of University of Trieste, Italy and the Department of Engineering of University of Ferrara, Italy, using the WADGPS (Wide Area Differential GPS) corrections up linked by Geostationary Satellites belonging to the American WAAS and European EGNOS. Recently, a prototypal service by ESA (European Space Agency) named SISNet (Signal In Space through Internet), has been introduced using Internet to diffuse the messages up linked through AOR-E and IOR Geostationary Satellites. This service will overcome the problems relative to the availability of the corrections in urban areas. This system is currently under tests by the authors in order to verify the latency of the message and the applicability and accuracies obtainable in particular in dynamic applications.

  16. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  17. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  18. Jovian magnetosphere-satellite interactions: aspects of energetic charged particle loss

    International Nuclear Information System (INIS)

    Thomsen, M.F.

    1979-01-01

    Observations of energetic charged particles obtained by Pioneers 10 and 11 near the orbits of the inner Jovian satellites are reviewed with particular emphasis on the implications of these observations with regard to possible models of the access of charged particles to the satellite surfaces. The observed effects on particle pitch angle distributions and the observed energy dependence of the intensity depletions seen at the satellite orbits are compared with predictions of satellite sweepup based on several different access models. The two major uncertainties which hamper the comparisons are those associated with the satellite conductivities and the ionospheric dynamo electric field power spectrum. The satellite conductivity is important because it governs the access of the particles to the satellite surface and therefore the lifetime tau: the dynamo power spectrum is important because it controls the magnitude and energy dependence of the radial diffusion coefficient. In spite of these uncertainties we can nevertheless make the following conclusions. The electron pitch angle distributions at Io's orbit are compatible with expectations based on sweeping. The energy dependences of the observed electron depletions at all three inner satellites (Amalthea, Io, and Europa) are incompatible with expectations based on a perfect conductor model of a satellite and its flux tube but are compatible with the energy dependence expected for perfectly insulating or partially conducting satellites However, the proton losses at Io are observed to be much stronger than the electron losses, in contradiction to expectations based on sweeping. The most attractive explanation for the proton-electron discrepancy at Io is that the large proton losses at Io's orbit are principally due to enhanced pitch angle scattering in the region of higher plasma density

  19. Antioxidant activities of some local bangladeshi fruits (Artocarpus heterophyllus, Annona squamosa, Terminalia bellirica, Syzygium samarangense, Averrhoa carambola and Olea europa).

    Science.gov (United States)

    Soubir, Titov

    2007-03-01

    In the present study, antioxidant activities of the fruits of A. heterophyllus, A. squamosa, T. bellirica, S. samarangense, A. carambola and O. europa were investigated. For this, at first matured fruits of them were sliced into small pieces and dried in the sun and finally crushed in a grinder to make powder. Ethanolic extracts of fruit powder were prepared using 99.99% ethanol. The antioxidative activities of these extracts were determined according to their abilities of scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical. It was demonstrated that all the ethanolic extracts of A. heterophyllus, A. squamosa, T. bellirica, S. samarangense, A. caranbola and O. europa showed antioxidant activities. The IC50 of the ethanolic extracts of A. heterophyllus, A. squamosa, T. bellirica, S. samarangense, A. carambola and O. europa were 410, 250, 34, 200, 30 and 76 microg/mL, respectively. Among them, A. carambola showed the highest antioxidant activities followed by T. bellirica, O. europa, S. samarangense, A. squamosa and A. heterophyllus indicating that fruits of A. carambola, T. bellirica and O. europa are very beneficial to human health.

  20. Assessing the potential for measuring Europa's tidal Love number h2 using radar sounder and topographic imager data

    Science.gov (United States)

    Steinbrügge, G.; Schroeder, D. M.; Haynes, M. S.; Hussmann, H.; Grima, C.; Blankenship, D. D.

    2018-01-01

    The tidal Love number h2 is a key geophysical measurement for the characterization of Europa's interior, especially of its outer ice shell if a subsurface ocean is present. We performed numerical simulations to assess the potential for estimating h2 using altimetric measurements with a combination of radar sounding and stereo imaging data. The measurement principle exploits both delay and Doppler information in the radar surface return in combination with topography from a digital terrain model (DTM). The resulting radar range measurements at cross-over locations can be used in combination with radio science Doppler data for an improved trajectory solution and for estimating the h2 Love number. Our simulation results suggest that the absolute accuracy of h2 from the joint analysis of REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) surface return and EIS (Europa Imaging System) DTM data will be in the range of 0.04-0.17 assuming full radio link coverage. The error is controlled by the SNR budget and DTM quality, both dependent on the surface properties of Europa. We estimate that this would unambiguously confirm (or reject) the global ocean hypothesis and, in combination with a nominal radio-science based measurement of the tidal Love number k2, constrain the thickness of Europa's outer ice shell to up to ±15 km.

  1. Lyman Alpha Camera for Io's SO2 atmosphere and Europa's water plumes

    Science.gov (United States)

    McEwen, Alfred S.; Sandel, Bill; Schneider, Nick

    2014-05-01

    The Student Lyman-Alpha Mapper (SLAM) was conceived for the Io Volcano Observer (IVO) mission proposal (McEwen et al., 2014) to determine the spatial and temporal variations in Io's SO2 atmosphere by recording the H Ly-α reflection over the disk (Feldman et al., 2000; Feaga et al., 2009). SO2 absorbs at H Ly-α, thereby modulating the brightness of sunlight reflected by the surface, and measures the density of the SO2 atmosphere and its variability with volcanic activity and time of day. Recently, enhancements at the Ly-α wavelength (121.57 nm) were seen near the limb of Europa and interpreted as active water plumes ~200 km high (Roth et al., 2014). We have a preliminary design for a very simple camera to image in a single bandpass at Ly-α, analogous to a simplified version of IMAGE EUV (Sandel et al. 2000). Our goal is at least 50 resolution elements across Io and/or Europa (~75 km/pixel), ~3x better than HST STIS, to be acquired at a range where the radiation noise is below 1E-4 hits/pixel/s. This goal is achieved with a Cassegrain-like telescope with a 10-cm aperture. The wavelength selection is achieved using a simple self-filtering mirror in combination with a solar-blind photocathode. A photon-counting detector based on a sealed image intensifier preserves the poisson statistics of the incoming photon flux. The intensifier window is coated with a solar-blind photocathode material (CsI). The location of each photon event is recorded by a position-sensitive anode based on crossed delay-line or wedge-and-strip technology. The sensitivity is 0.01 counts/pixel/sec/R, sufficient to estimate SO2 column abundances ranging from 1E15 to 1E17 per cm2 in a 5 min (300 sec) exposure. Sensitivity requirements to search for and image Europa plumes may be similar. Io's Ly-α brightness of ~3 kR exceeds the 0.8 kR brightness of Europa's plume reported by Roth et al. (2014), but the plume brightness is a direct measurement rather than inferring column abundance from

  2. DETECTION OF A HYDROGEN CORONA IN HST Ly α IMAGES OF EUROPA IN TRANSIT OF JUPITER

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Lorenz; Ivchenko, Nickolay; Schlatter, Nicola [KTH Royal Institute of Technology (Sweden); Retherford, Kurt D.; Becker, Tracy M.; Grava, Cesare [Southwest Research Institute, San Antonio, TX (United States); Strobel, Darrell F. [Johns Hopkins University, Baltimore, MD (United States)

    2017-02-01

    We report far-ultraviolet observations of Europa in transit of Jupiter obtained with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope on six occasions between 2014 December and 2015 March. Absorption of Jupiter’s bright hydrogen Ly α dayglow is detected in a region several moon radii above the limb in all observations. The observed extended absorption provides the first detection of an atomic hydrogen corona around Europa. Molecular constituents in Europa’s global sputtered atmosphere are shown to be optically thin to Ly α . The observations are consistent with a radially escaping H corona with maximum densities at the surface in the range of (1.5–2.2) × 10{sup 3} cm{sup −3}, confirming the abundances predicted by Monte Carlo simulations. In addition, we search for anomalies around the limb of Europa from absorption by localized high H{sub 2}O abundances from active plumes. No significant local absorption features are detected. We find that an H{sub 2}O plume with line-of-sight column density in the order of 10{sup 16} cm{sup −2}, as inferred by Roth et al. would not be detectable based on the statistical fluctuations of the transit measurements, and hence is not excluded or further constrained. The presence of plumes with line-of-sight column densities of >2 × 10{sup 17} cm{sup −2} can be excluded at a 3- σ level during five of our six observations.

  3. Duda y posmodernidad: el ocaso de la secularización en Europa

    Directory of Open Access Journals (Sweden)

    EDUARDO BERICAT ALASTUEY

    2008-01-01

    Full Text Available En este trabajo se presentan los resultados de un análisis empírico y teórico desarrollado con el objeto de determinar el estado actual de la religiosidad en Europa, es decir, el grado en que los europeos se adscriben bien a una cosmovisión religiosa, bien a una cosmovisión secular. Aplicando el Análisis de Correspondencias Múltiples y el Análisis de Cluster K-medias a los datos de la encuesta europea "Religión-II", del ISSP, se ha elaborado una tipología compuesta por cinco posiciones culturales básicas: religiosos, creyentes, escépticos, agnósticos y ateos. Estos resultados han puesto de manifiesto tanto la extensión cuantitativa como la importancia cualitativa del escepticismo. Mediante la interpretación del contenido de cada uno de los tipos, se muestra que el escepticismo frente a las opciones religiosa o secular constituye en este momento una clave esencial de la cultura europea. No puede hablarse de un claro retorno de lo religioso, pero es evidente que el proceso de secularización ha perdido parte de su fuerza original. La Europa posmoderna se encuentra inmersa en una encrucijada cultural, y tendrá que decidir sobre su futuro. El artículo termina exponiendo las tres posibles estrategias de salida de la duda: la resolución kierkegaardiana, mediante la que los europeos afirmarán posiciones religiosas o seculares excluyentes; la solución borgiana, mediante la que se hibridarán las formas y contenidos religiosos y seculares; y la disolución hegeliana, mediante la que quizás Europa despliegue en el futuro una síntesis cultural nueva construida con los restos de las viejas cosmovisiones religiosa y secular.

  4. Communication satellite applications

    Science.gov (United States)

    Pelton, Joseph N.

    The status and future of the technologies, numbers and services provided by communications satellites worldwide are explored. The evolution of Intelsat satellites and the associated earth terminals toward high-rate all-digital telephony, data, facsimile, videophone, videoconferencing and DBS capabilities are described. The capabilities, services and usage of the Intersputnik, Eutelsat, Arabsat and Palapa systems are also outlined. Domestic satellite communications by means of the Molniya, ANIK, Olympus, Intelsat and Palapa spacecraft are outlined, noting the fast growth of the market and the growing number of different satellite manufacturers. The technical, economic and service definition issues surrounding DBS systems are discussed, along with presently operating and planned maritime and aeronautical communications and positioning systems. Features of search and rescue and tracking, data, and relay satellite systems are summarized, and services offered or which will be offered by every existing or planned communication satellite worldwide are tabulated.

  5. Historiografía española sobre Europa Central y Oriental. Nacionalismo, transiciones poscomunistas y relaciones exteriores

    OpenAIRE

    Sánchez García, Raquel

    2009-01-01

    La historiografía española no ha prestado especial atención a la Europa central y oriental pues sus objetivos han estado localizados en otros entornos geográficos como la Europa Occidental o América. Sin embargo, desde la caída de las dictaduras comunistas se despertó un gran interés por esta zona de Europa, interés que nació primero en los estudios económicos y políticos y que poco a poco ha ido trasladándose a la historia. [ABSTRAC]Traditionally, Spanish historiography hasn’t paid attent...

  6. Historia política y social contemporánea de Europa. Siglo XIX

    OpenAIRE

    Samaniego Boneu, Mercedes

    2009-01-01

    Materiales de clase: 1.1789-1870. La era de las revoluciones. El ascenso de la burguesía y la aparición del proletariado. Tema 1: La Revolución en Francia. La penetración de la revolución en Europa. Elsistema y la obra de Napoleón. (Parte 1) (Parte 2); Tema 2: La contrarrevolución europea: El Congreso de Viena. Francia: desde laetapa de la Restauración al Segundo Imperio. Reino Unido: Restablecimiento y reforma: la era Palmerston . (Parte 1) (Parte 2); Tema 3: El diagnóstico microbiológico e...

  7. Fault offsets and lateral crustal movement on Europa - Evidence for a mobile ice shell

    International Nuclear Information System (INIS)

    Schenk, P.M.; Mckinnon, W.B.

    1989-01-01

    An examination is conducted of Europa's cross-cutting structural relationships between various lineament types, in order to constrain the type of structure involved in each such case and, where possible, to also constrain the degree of extension across the lineaments. Evidence is adduced for significant lateral crustal movement, allowing alternative models and mechanisms for lineament formation to be discussed, as well as plausible lithospheric and crustal models. The question as to whether any of the water-ice layer has been, or currently is, liquid, is also treated in light of the evidence obtained. 53 refs

  8. Las cubiertas medievales de los templos del sur de Europa: procedimientos de intervención

    OpenAIRE

    Benitez Bodes, Rosa María

    2016-01-01

    Falta resumen y palabras claves Esta Tesis centra su estudio en las cubiertas de los templos medievales (s.XIII-s.XVI) resueltas mediante azoteas o trasdosados en el Sur de Europa, solución particular que fue posible gracias a, fundamentalmente, la climatología, el comportamiento sísmico del ámbito geográfico donde se utiliza, la disponibilidad y acceso a las materias primas necesarias y la integración de culturas y tradiciones constructivas heredadas presentes en todo el arco del mar Medi...

  9. El otro como punto de referencia para la educación en Europa

    OpenAIRE

    Wulf, Christoph

    2002-01-01

    En Europa la educación se tiene que convertir en una responsabilidad intercultural que considere las similitudes y diferencias entre las diferentes culturas. Cada cultura es una diversidad profunda. Por eso es importante fortalecer eso que es "otro" y apoyar la particularidades de cada cultura dada. Aceptar las diferencias es condición para crear una conciencia intercultural. El otro es un espejo en el cual vemos, descubrimos y nos investigamos a nosotros mismos. Él es la contraparte de l...

  10. Hybrid Simulation of the Interaction of Europa's Atmosphere with the Jovian Plasma: Multiprocessor Simulations

    Science.gov (United States)

    Dols, V. J.; Delamere, P. A.; Bagenal, F.; Cassidy, T. A.; Crary, F. J.

    2014-12-01

    We model the interaction of Europa's tenuous atmosphere with the plasma of Jupiter's torus with an improved version of our hybrid plasma code. In a hybrid plasma code, the ions are treated as kinetic Macro-particles moving under the Lorentz force and the electrons as a fluid leading to a generalized formulation of Ohm's law. In this version, the spatial simulation domain is decomposed in 2 directions and is non-uniform in the plasma convection direction. The code is run on a multi-processor supercomputer that offers 16416 cores and 2GB Ram per core. This new version allows us to tap into the large memory of the supercomputer and simulate the full interaction volume (Reuropa=1561km) with a high spatial resolution (50km). Compared to Io, Europa's atmosphere is about 100 times more tenuous, the ambient magnetic field is weaker and the density of incident plasma is lower. Consequently, the electrodynamic interaction is also weaker and substantial fluxes of thermal torus ions might reach and sputter the icy surface. Molecular O2 is the dominant atmospheric product of this surface sputtering. Observations of oxygen UV emissions (specifically the ratio of OI 1356A / 1304A emissions) are roughly consistent with an atmosphere that is composed predominantely of O2 with a small amount of atomic O. Galileo observations along flybys close to Europa have revealed the existence of induced currents in a conducting ocean under the icy crust. They also showed that, from flyby to flyby, the plasma interaction is very variable. Asymmetries of the plasma density and temperature in the wake of Europa were also observed and still elude a clear explanation. Galileo mag data also detected ion cyclotron waves, which is an indication of heavy ion pickup close to the moon. We prescribe an O2 atmosphere with a vertical density column consistent with UV observations and model the plasma properties along several Galileo flybys of the moon. We compare our results with the magnetometer

  11. LA REPRODUCCIÓN ASISTIDA EN EUROPA: LA LABOR ARMONIZADORA DEL TRIBUNAL EUROPEO DE DERECHOS HUMANOS

    OpenAIRE

    Mª DEL PILAR MOLERO MARTÍN-SALAS

    2016-01-01

    Uno de los principales avances científicos de las últimas décadas ha sido la reproducción asistida. Ello ha provocado la aparición de nuevos problemas jurídicos que han sido resueltos en Europa por sus Estados miembro de manera heterogénea, convirtiendo la interpretación del Tribunal Europeo de Derechos Humanos en estos últimos años en necesaria y crucial para entender la regulación europea al respecto. En este trabajo se muestra la labor de interpretación realizada por el Tribunal respec...

  12. Revolucions, màquines i música a l'Europa de 1800

    OpenAIRE

    Brugarolas, Oriol, 1979-

    2016-01-01

    Els processos revolucionaris que es desenvoluparen a Europa entre la segona meitat del segle XVIII i el primer terç del segle XIX varen soscavar els fonaments de l’Antic Règim i van portar a la formació del món contemporani. Tot es transformà, lenta i gradualment al llarg de tres generacions: la industria va substituir l’artesania i la manufactura; els sistemes monàrquics absolutistes van anar desapareixent per donar pas a sistemes polítics liberals parlamentaris; la societat estamental va de...

  13. La justiciabilidad de los derechos sociales en el Consejo de Europa

    OpenAIRE

    Nivard, Carole

    2016-01-01

    Los derechos sociales están generalmente menos protegidos que los derechos civiles y políticos. Sin embargo, en el ámbito del Consejo de Europa, los sistemas de la Carta social europea y del Convenio europeo de los derechos humanos ofrecen las condiciones para un avanzar hacia la justiciabilidad de los derechos sociales. El Tribunal Europeo de Derechos Humanos evoluciona y adopta una interpretación dinámica que amplía los derechos del Convenio europeo hasta la esfera social. Por otra parte, e...

  14. A Europa, as migrações e o cosmopolitismo

    Directory of Open Access Journals (Sweden)

    Octávio Sacramento

    2016-07-01

    Full Text Available ResumoO análise aqui delineado discute as posturas das fronteiras europeias em relação aos desafios colocados pelos fluxos migratórios externos. É dada especial atenção à forma como a Europa, através do Acordo de Schengen, estabelece uma combinação estratégica entre a livre circulação de certas categorias de pessoas e o bloqueio de muitas outras mobilidades “indesejados”. Ao mesmo tempo, são considerados resumidamente as políticas de identidade subjacentes a seletividade do espaço Schengen e seu impacto sobre um projecto europeu pós-nacional e cosmopolita. Palavras-chave: Europa, Migração externa, Fronteiras e limites, Seletividade, Cosmopolitismo. Resumen En el análisis esbozado aquí se analizan las actitudes en las fronteras europeas en relación con los retos que plantea la migración externa. Se presta especial atención a la forma en Europa a través del Acuerdo de Schengen, establece una combinación estratégica de la libre circulación de ciertas categorías de personas y el bloqueo de muchas otras movilida- des “no deseadas”. Al mismo tiempo, se consideran brevemente la política de la identidad subyacente en la selectividad de la zona Schengen y su impacto en un proyecto europeo post-nacional y cosmopolita. Palabras clave: Europa, La migración externa, Fronteras y límites, La selectividad, Cosmopolitismo. Abstract The analysis outlined in this paper discusses the attitudes of the European borders in relation to the challenges posed by external migration flows. Special attention is given to the way Europe, through the Schengen Agreement, establishes a strategic combination between the free movement of certain categories of people and the blocking of many other “un- wanted” mobilities. At the same time, the paper briefly considers the identity policies underlying the selectivity of the Schengen area and their impact on a post-national and cosmopolitan European project

  15. Bιβλιοκρισία: M. ALTRIPP (Ηrsg., Byzanz in Europa. Europas östliches Erbe. [BYZANTIOS. Studies in Byzantine History and Civilization 2], Turnhout 2011, ISBN 978-2-503-54153-2

    Directory of Open Access Journals (Sweden)

    Στυλιανός ΛΑΜΠΑΚΗΣ

    2014-04-01

    Full Text Available Βιβλιοκρισία: M. Altripp (Ηrsg., Byzanz in Europa. Europas östliches Erbe. Akten des Kolloquiums 'Byzanz in Europa' vom 11. bis 15. Dezember 2007 in Greifswald [BYZANTIOS. Studies in Byzantine History and Civilization 2], Turnhout 2011, σελ. X + 502, 79 πίν., ISBN 978-2-503-54153-2 (printed version- 978-2-503-54193-8 (online version.

  16. Satellite services system overview

    Science.gov (United States)

    Rysavy, G.

    1982-01-01

    The benefits of a satellite services system and the basic needs of the Space Transportation System to have improved satellite service capability are identified. Specific required servicing equipment are discussed in terms of their technology development status and their operative functions. Concepts include maneuverable television systems, extravehicular maneuvering unit, orbiter exterior lighting, satellite holding and positioning aid, fluid transfer equipment, end effectors for the remote manipulator system, teleoperator maneuvering system, and hand and power tools.

  17. Improved OSC Amtec generator design to meet goals of JPL's candidate Europa Orbiter mission

    International Nuclear Information System (INIS)

    Schock, A.; Noravian, H.; Or, C.; Kumar, V.

    1998-01-01

    The preceding paper (Paper IECEC.98.244) described OSC's initial designs of AMTEC (Alkali Metal Thermal-to-Electrical Conversion) power systems, consisting of one or two generators, each with 2, 3, or 4 General Purpose Heat Source (GPHS) modules and with 16 refractory AMTEC cells containing 5 Beta Alumina Solid Electrolyte (BASE) tubes; and presented the effect of heat input and voltage output on the generator's BOM evaporator and clad temperatures and on its EOM system efficiency and power output. Comparison of the computed results with JPL's goals for the Europa Orbiter mission showed that all of the initial 16-cell design options yielded either excessive evaporator and clad temperatures or insufficient EOM power to satisfy the JPL-specified mission goals. The present paper describes modified OSC generator designs with different numbers of AMTEC cells, cell diameters, cell lengths, cell materials, BASE tube lengths, and number of tubes per cell. These efforts succeeded in identifying generator designs with only half the number of AMTEC cells which -- for the same assumptions -- can produce EOM power outputs substantially in excess of JPL's goals for NASA's Europa Orbiter mission while operating well below the prescribed BOM limits on evaporator and clad temperature; and revealed that lowering the emissivity of the generator's housing to raise the cells' condenser temperatures can achieve substantial additional performance improvement. Finally, the paper culminates in programmatic recommendations

  18. Fronteras imaginadas y estereotipos : la creación de un monstruo llamado Europa del Este

    Directory of Open Access Journals (Sweden)

    Daniel Esparza

    2009-01-01

    Full Text Available En este artículo se observa como se han formado en el «oeste», desde la Guerra Fría hasta hoy, algunos estereotipos negativos sobre la marca «Europa del Este», la cual está cargada de connotaciones negativas (ciudades grises, guerras, inmigración ilegal, pobreza o criminalidad. Al mismo tiempo, como si de un oasis se tratara, se observa parojicamente como la marca Praga o Budapest (capitales de países de «Europa del Este» no son percibidas negativamente, precisamente porque no están relacionadas directamente con el Este, sino con centroeuropa y con imágenes positivas asociadas a la herencia artístico-cultural de los imperios centrales: el sacro imperio germano-romano y el austrohúngaro.In this article it is observed how from the Cold War till today have been formed in the West significant stereotypes towards Eastern Europe, which are endowed with negative images, such as grey towns, illegal immigration, wars, poverty or criminality. At the same time it is observed, paradoxically, how the brand Prague or Budapest (capitals of «Eastern European» countries are not perceived negatively, precisely because they are not directly associated with the East, but with the cultural heritage form the old central empires: the Sacred Roman-German empire first, and the Habsburg empire later.

  19. Von der Europäischen Rechtsgeschichte zu einer Rechtsgeschichte Europas in globalhistorischer Perspektive

    Directory of Open Access Journals (Sweden)

    Thomas Duve

    2012-01-01

    In den letzten Jahren sind im Zuge der Diskussion um postkoloniale Perspektiven auf die Geschichte, um Transnationale und Globalgeschichte, viele Grundlagen der traditionellen Europahistoriographie kritisiert und massiv erschüttert worden. Das wirft Fragen auch an die Europäische Rechtsgeschichte auf: Welches Europabild liegt ihr zu Grunde? Auf welchen intellektuellen und konzeptionellen Grundlagen beruht sie? Wie antwortet sie auf die Vorwürfe des Eurozentrismus, des epistemischen Kolonialismus, wie auf die Forderung, Europa zu ›provinzialisieren‹? Wie definiert sie das Verhältnis der Europäischen zur Transnationalen und Globalen Rechtsgeschichte? – Diesen und ähnlichen Fragen wenden sich die folgenden Überlegungen zu. Der Schwerpunkt liegt auf einer Auseinandersetzung mit der Tradition, ihren konzeptionellen Grundlagen und deren wissenschaftshistorischem Kontext (1. Teil, 1.–6.. Aus dieser kritischen Bestandsaufnahme und den Ergebnissen der Debatte um Globalgeschichte ergeben sich Ausgangspunkte und Aufgaben einer in Vielem auf den Leistungen der Disziplin aufbauenden, doch notwendigerweise auf einer anderen Konzeption beruhenden Rechtsgeschichte Europas in globalhistorischer Perspektive (2. Teil, 7.–11..

  20. El caso Breivik como paradigma de la nueva violencia política en Europa

    Directory of Open Access Journals (Sweden)

    Jesús Pérez

    2014-01-01

    Full Text Available Tras el doble atentado en Noruega del 22 de julio de 2011 cometido por Anders Behring Breivik, el terrorismo en Europa se enfrenta a una nueva amenaza. La novedad ideológica de Breivik es escasa, salvo por actualizar peligros que parecían del pasado. Por el contrario, su novedad operativa sí es relevante, ya que demuestra la posibilidad de la actuación de "lobos solitarios" en Europa y ejemplifica de qué manera el occidental medio puede actuar con un potencial muy alto de causar daños. Se concluye con el avance de un nuevo paradigma, el de sujetos que actúan movidos políticamente por un objetivo irrealizable, para favorecer a grupos que son extremadamente abstractos o no existen, lo que les proporciona un blindaje ideológico sin capacidad alta de movilización pero con destacadas cotas de destrucción.

  1. Commentary: The Feasibility of Subduction and Implications for Plate Tectonics on Jupiter's Moon Europa

    Science.gov (United States)

    Kattenhorn, Simon A.

    2018-03-01

    A new modeling-based study by Johnson et al. (2017, https://doi.org/10.1002/2017JE005370) lends support to the hypothesis that portions of Europa's surface may have been removed by the process of subduction, as suggested by Kattenhorn and Prockter (2014, https://doi.org/10.1038/NGEO2245). Using a simple 1-D model that tracks the thermal and density structure of a descending ice plate, Johnson et al. show that ice plates with 10% porosity and overall salt contents of 5%, which differ in salt content by 2.5% from the surrounding reference ice shell, are nonbuoyant and thus likely to sink through the underlying, convecting portion of the ice shell. The feasibility of subduction in an ice shell is critical to the existence of icy plate tectonics, which is hypothesized to exist at least locally on Europa, potentially making it the only other Solar System body other than Earth with a surface modified by plate tectonics.

  2. Czesław Miłosz’s Migrant Perspective in Rodzinna Europa [Native Realm

    Directory of Open Access Journals (Sweden)

    Kołodziejczyk Ewa

    2017-11-01

    Full Text Available The article traces the impact of Czesław Miłosz’s first American stay on his image of Central Europe in Rodzinna Europa [Native Realm]. In the United States, the post-war immigrant from Vilnius learned to perceive, understand and evaluate American culture; he also gained a new perspective on his region of Europe and Slavic immigrants. This experience enabled him to adopt an American point of view in his autobiographical essay. Following William Faulkner, Miłosz carries on an analysis of Eastern and Central Europe’s history and identities. The uses Western historical and sociological glossary to describe processes that formed his “native realm.” Analogically, the poet from pre-war Vilnius reflects on American multi-ethnicity and religious diversity from a Central European perspective. In Rodzinna Europa, Miłosz takes the position of a migrant translator and a two-way mediator between East and West.

  3. Thermal Coupling Between the Ocean and Mantle of Europa: Implications for Ocean Convection

    Science.gov (United States)

    Soderlund, Krista M.; Schmidt, Britney E.; Wicht, Johannes; Blankenship, Donald D.

    2015-11-01

    Magnetic induction signatures at Europa indicate the presence of a subsurface ocean beneath the cold icy crust. The underlying mantle is heated by radioactive decay and tidal dissipation, leading to a thermal contrast sufficient to drive convection and active dynamics within the ocean. Radiogenic heat sources may be distributed uniformly in the interior, while tidal heating varies spatially with a pattern that depends on whether eccentricity or obliquity tides are dominant. The distribution of mantle heat flow along the seafloor may therefore be heterogeneous and impact the regional vigor of ocean convection. Here, we use numerical simulations of thermal convection in a global, Europa-like ocean to test the sensitivity of ocean dynamics to variations in mantle heat flow patterns. Towards this end, three end-member cases are considered: an isothermal seafloor associated with dominant radiogenic heating, enhanced seafloor temperatures at high latitudes associated with eccentricity tides, and enhanced equatorial seafloor temperatures associated with obliquity tides. Our analyses will focus on convective heat transfer since the heat flux pattern along the ice-ocean interface can directly impact the ice shell and the potential for geologic activity within it.

  4. Detectability of thermal signatures associated with active formation of ‘chaos terrain’ on Europa

    Science.gov (United States)

    Abramov, Oleg; Rathbun, J.; Schmidt, Britney E.; Spencer, John R.

    2013-01-01

    A recent study by Schmidt et al. (2011) suggests that Thera Macula, one of the “chaos regions” on Europa, may be actively forming over a large liquid water lens. Such a process could conceivably produce a thermal anomaly detectable by a future Europa orbiter or flyby mission, allowing for a direct verification of this finding. Here, we present a set of models that quantitatively assess the surface and subsurface temperatures associated with an actively resurfacing chaos region using constraints from Thera Macula. The results of this numerical study suggest that the surface temperature over an active chaos region can be as high as ∼200 K. However, low-resolution Galileo Photo-Polarimeter Radiometer (PPR) observations indicate temperatures below 120 K over Thera Macula. This suggests that Thera Macula is not currently active unless an insulating layer of at least a few centimeters in thickness is present, or activity is confined to small regions, reducing the overall intensity of the thermal signature. Alternatively, Thera may have been cooling for at least 10–100 yr and still contain a subsurface lake, which can take ∼300,000 yr to crystallize. According to the present study, a more sensitive instrument capable of detecting anomalies ∼5 K above ambient could detect activity at Thera Macula even if an insulating layer of ∼50 cm is present.

  5. Rutas y lugares de patrimonio industrial en Europa : consideraciones sobre su aprovechamiento turístico

    Directory of Open Access Journals (Sweden)

    Carlos J. Pardo Abad

    2002-01-01

    Full Text Available Muchas zonas de Europa se han caracterizado en los dos últimos siglos a través de la actividad industrial. Los edificios industriales son tanto el testimonio del desarrollo económico y social como la expresión de la identidad regional. Conservándolos y haciendo de ellos algo útil para la población se consigue mantener vivo un importante aspecto de la historia europea, creando una base potencial para un nuevo desarrollo económico y regional. El patrimonio industrial ofrece muchas oportunidades como recurso turístico y hay muchos ejemplos al respecto en Europa: museos, centros culturales y de interpretación se han abierto en viejas fábricas ya abandonadas.Many areas of Europe have been characterised in recent centuries by industrial activity. Industrial buildings are both the witness of economic and social development and the expression of regional identity. Preserving them and making them available to the population helps to keep this important aspect of European history alive, and creates a potential basis for new economic and regional development. Industrial heritage offers many opportunities as a tourist resource and there are numerous examples in Europe: museums, cultural and interpretation centres have been created in old abandoned faetones.

  6. The San Andreas Fault and a Strike-slip Fault on Europa

    Science.gov (United States)

    1998-01-01

    The mosaic on the right of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, the size of the California portion of the San Andreas fault on Earth which runs from the California-Mexico border north to the San Francisco Bay. The left mosaic shows the portion of the San Andreas fault near California's san Francisco Bay that has been scaled to the same size and resolution as the Europa image. Each covers an area approximately 170 by 193 kilometers(105 by 120 miles). The red line marks the once active central crack of the Europan fault (right) and the line of the San Andreas fault (left). A strike-slip fault is one in which two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. The overall motion along the Europan fault seems to have followed a continuous narrow crack along the entire length of the feature, with a path resembling stepson a staircase crossing zones which have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. Opposite sides of the fault can be reconstructed like a puzzle, matching the shape of the sides as well as older individual cracks and ridges that had been broken by its movements. Bends in the Europan fault have allowed the surface to be pulled apart. This pulling-apart along the fault's bends created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, and in Death Valley and the Dead Sea. In those cases, the pulled apart regions can include upwelled materials, but may

  7. Radiation Testing at Sandia National Laboratories: Sandia – JPL Collaboration for Europa Lander

    Energy Technology Data Exchange (ETDEWEB)

    Hattar, Khalid Mikhiel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Ion Beam Lab.; Olszewska-Wasiolek, Maryla Aleksandra [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Gamma Irradiation Facility

    2017-01-01

    Sandia National Laboratories (SNL) is assisting Jet Propulsion Laboratory in undertaking feasibility studies and performance assessments for the Planetary Protection aspect of the Europa Lander mission. The specific areas of interest for this project are described by task number. This white paper presents the evaluation results for Task 2, Radiation Testing, which was stated as follows: Survey SNL facilities and capabilities for simulating the Europan radiation environment and assess suitability for: A. Testing batteries, electronics, and other component and subsystems B. Exposing biological organisms to assess their survivability metrics. The radiation environment the Europa Lander will encounter on route and in orbit upon arrival at its destination consists primarily of charged particles, energetic protons and electrons with the energies up to 1 GeV. The charged particle environments can be simulated using the accelerators at the Ion Beam Laboratory. The Gamma Irradiation Facility and its annex, the Low Dose Rate Irradiation Facility, offer irradiations using Co-60 gamma sources (1.17 and 1.33 MeV), as well as Cs-137 gamma (0.661 MeV) AmBe neutron (0-10 MeV) sources.

  8. Satellite Communications Industry

    Science.gov (United States)

    1993-04-01

    Ariane $loom SAJAC 1 Hughes Satellite Japan 06/94 $150m SAJAC 2 Hughes Satellite Japan -- (spare) $150m SatcomHl GE GE Americom /95 $50m SOLIDARIDAD ...1 Hughes SCT (Mexico) 11/93 Ariane $loom SOLIDARIDAD 2 Hughes SCT (Mexico) /94 $loom Superbird Al Loral Space Com Gp (Jap) 11/92 Ariane $175m

  9. Partnership via Satellite.

    Science.gov (United States)

    Powell, Marie Clare

    1980-01-01

    Segments of the 1980 National Catholic Educational Association (NCEA) conference were to be telecast nationally by satellite. The author briefly explains the satellite transmission process and advises Catholic educators on how to pick up the broadcast through their local cable television system. (SJL)

  10. The satellite situation center

    International Nuclear Information System (INIS)

    Teague, M.J.; Sawyer, D.M.; Vette, J.I.

    1982-01-01

    Considerations related to the early planning for the International Magnetospheric Study (IMS) took into account the desirability of an establishment of specific entities for generating and disseminating coordination information for both retrospective and predictive periods. The organizations established include the IMS/Satellite Situation Center (IMS/SSC) operated by NASA. The activities of the SSC are related to the preparation of reports on predicted and actually achieved satellite positions, the response to inquiries, the compilation of information on satellite experiments, and the issue of periodic status summaries. Attention is given to high-altitude satellite services, other correlative satellite services, non-IMS activities of the SSC, a summary of the SSC request activity, and post-IMS and future activities

  11. Design of an Autonomous Underwater Vehicle to Calibrate the Europa Clipper Ice-Penetrating Radar

    Science.gov (United States)

    Stone, W.; Siegel, V.; Kimball, P.; Richmond, K.; Flesher, C.; Hogan, B.; Lelievre, S.

    2013-12-01

    Jupiter's moon Europa has been prioritized as the target for the Europa Clipper flyby mission. A key science objective for the mission is to remotely characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange. This objective is a critical component of the mission's overarching goal of assessing the habitability of Europa. The instrument targeted for addressing key aspects of this goal is an ice-penetrating radar (IPR). As a primary goal of our work, we will tightly couple airborne IPR studies of the Ross Ice Shelf by the Europa Clipper radar team with ground-truth data to be obtained from sub-glacial sonar and bio-geochemical mapping of the corresponding ice-water and water-rock interfaces using an advanced autonomous underwater vehicle (AUV). The ARTEMIS vehicle - a heavily morphed long-range, low drag variant of the highly successful 4-degree-of-freedom hovering sub-ice ENDURANCE bot -- will be deployed from a sea-ice drill hole adjacent the McMurdo Ice Shelf (MIS) and will perform three classes of missions. The first includes original exploration and high definition mapping of both the ice-water interface and the benthic interface on a length scale (approximately 10 kilometers under-ice penetration radius) that will definitively tie it to the synchronous airborne IPR over-flights. These exploration and mapping missions will be conducted at up to 10 different locations along the MIS in order to capture varying ice thickness and seawater intrusion into the ice shelf. Following initial mapping characterization, the vehicle will conduct astrobiology-relevant proximity operations using bio-assay sensors (custom-designed UV fluorescence and machine-vision-processed optical imagery) followed by point-targeted studies at regions of interest. Sample returns from the ice-water interface will be triggered autonomously using real-time-processed instrument data and onboard decision-to-collect algorithms

  12. The rotation and fracture history of Europa from modeling of tidal-tectonic processes

    Science.gov (United States)

    Rhoden, Alyssa Rose

    Europa's surface displays a complex history of tectonic activity, much of which has been linked to tidal stress caused by Europa's eccentric orbit and possibly non-synchronous rotation of the ice shell. Cycloids are arcuate features thought to have formed in response to tidal normal stress while strike-slip motion along preexisting faults has been attributed to tidal shear stress. Tectonic features thus provide constraints on the rotational parameters that govern tidal stress, and can help us develop an understanding of the tidal-tectonic processes operating on ice covered ocean moons. In the first part of this work (Chapter 3), I test tidal models that include obliquity, fast precession, stress due to non-synchronous rotation (NSR), and physical libration by comparing how well each model reproduces observed cycloids. To do this, I have designed and implemented an automated parameter-searching algorithm that relies on a quantitative measure of fit quality to identify the best fits to observed cycloids. I apply statistical techniques to determine the tidal model best supported by the data and constrain the values of Europa's rotational parameters. Cycloids indicate a time-varying obliquity of about 1° and a physical libration in phase with the eccentricity libration, with amplitude >1°. To obtain good fits, cycloids must be translated in longitude, which implies non-synchronous rotation of the icy shell. However, stress from NSR is not well-supported, indicating that the rotation rate is slow enough that these stresses relax. I build upon the results of cycloid modeling in the second section by applying calculations of tidal stress that include obliquity to the formation of strike-slip faults. I predict the slip directions of faults with the standard formation model---tidal walking (Chapter 5)---and with a new mechanical model I have developed, called shell tectonics (Chapter 6). The shell tectonics model incorporates linear elasticity to determine slip and stress

  13. Exploration of Icy Moons in the Outer Solar System: Updated Planetary Protection Requirements for Missions to Enceladus and Europa

    Science.gov (United States)

    Rummel, J. D.; Race, M. S.

    2016-12-01

    Enceladus and Europa are bodies with icy/watery environments and potential habitable conditions for life, making both of great interest in astrobiological studies of chemical evolution and /or origin of life. They are also of significant planetary protection concern for spacecraft missions because of the potential for harmful contamination during exploration. At a 2015 COSPAR colloquium in Bern Switzerland, international scientists identified an urgent need to establish planetary protection requirements for missions proposing to return samples to Earth from Saturn's moon Enceladus. Deliberations at the meeting resulted in recommended policy updates for both forward and back contamination requirements for missions to Europa and Enceladus, including missions sampling plumes originating from those bodies. These recently recommended COSPAR policy revisions and biological contamination requirements will be applied to future missions to Europa and Encealadus, particularly noticeable in those with plans for in situ life detection and sample return capabilities. Included in the COSPAR policy are requirementsto `break the chain of contact' with Europa or Enceladus, to keep pristine returned materials contained, and to complete required biohazard analyses, testing and/or sterilization upon return to Earth. Subsequent to the Bern meeting, additional discussions of Planetary Protection of Outer Solar System bodies (PPOSS) are underway in a 3-year study coordinated by the European Science Foundation and involving multiple international partners, including Japan, China and Russia, along with a US observer. This presentation will provide science and policy updates for those whose research or activities will involve icy moon missions and exploration.

  14. Chemistry of Frozen NaCl and MgSO4 Brines - Implications for Surface Expression of Europa's Ocean Composition

    Science.gov (United States)

    Johnson, P. V.; Hodyss, R. P.; Choukroun, M.; Vu, T. H.

    2015-12-01

    The composition of Europa's subsurface ocean is a critical determinant of its habitability, but current analysis of the ocean composition is limited to its expression on the Europan surface. While there is observational evidence indicating that ocean materials make their way to the surface, our understanding of the chemical processes that can alter this material under Europan surface conditions is limited. We present experimental data on the chemistry of mixed solutions of NaCl and MgSO4 as they are frozen to 100 K, replicating the conditions that may occur when subsurface ocean fluids are emplaced onto Europa's surface. Confocal micro-Raman spectroscopy is used to study the formation of salts during the freezing process, and the interaction of ions in the frozen brines. Our data indicate that mixed aqueous solutions of NaCl and MgSO4 form Na2SO4 and MgCl2 preferentially when frozen, rather than making NaCl and MgSO4 precipitates. The detection of epsomite (MgSO4Ÿ•7H2O) on Europa's surface may therefore imply an ocean composition relatively low in sodium, unless radiolytic chemistry converts MgCl2 to MgSO4 as suggested by Hand and Brown 2013 (ApJ 145 110). These results have important implications for the interpretation of remote sensing data of Europa's surface.

  15. Tuta absoluta: una nueva plaga para el cultivo del tomate en Europa (Sesión Técnia: Hortalizas)

    NARCIS (Netherlands)

    Stol, W.; Griepink, F.C.; Deventer, van P.

    2009-01-01

    Tuta absoluta es una polilla originaria de Chile cuyas larvas producen minas en las hojas de las plantas de tomate. En las últimas décadas de este insecto se ha extendido por gran parte del continente sudamericano. Después de su primera observación en Europa (España, Valencia) en 2007, esta polilla

  16. Main magnetic field of Jupiter and its implications for future orbiter missions

    Science.gov (United States)

    Acuna, M. H.; Ness, N. F.

    1975-01-01

    A very strong planetary magnetic field and an enormous magnetosphere with extremely intense radiation belts exist at Jupiter. Pioneer 10 and 11 fly-bys confirmed and extended the earlier ground based estimates of many of these characteristics but left unanswered or added to the list of several important and poorly understood features: the source mechanism and location of decametric emissions, and the absorption effects by the natural satellites Amalthea, Io, Europa and Ganymede. High inclination orbits (exceeding 60 deg) with low periapses (less than 2 Jupiter radii) are required to map the radiation belts and main magnetic field of Jupiter accurately so as to permit full investigation of these and associated phenomena.

  17. Probability of satellite collision

    Science.gov (United States)

    Mccarter, J. W.

    1972-01-01

    A method is presented for computing the probability of a collision between a particular artificial earth satellite and any one of the total population of earth satellites. The collision hazard incurred by the proposed modular Space Station is assessed using the technique presented. The results of a parametric study to determine what type of satellite orbits produce the greatest contribution to the total collision probability are presented. Collision probability for the Space Station is given as a function of Space Station altitude and inclination. Collision probability was also parameterized over miss distance and mission duration.

  18. Extensional and compressional instabilities in icy satellite lithospheres

    International Nuclear Information System (INIS)

    Herrick, D.L.; Stevenson, D.J.

    1990-01-01

    The plausibility of invoking a lithospheric instability mechanism to account for the grooved terrains on Ganymede, Encedalus, and Miranda is presently evaluated in light of the combination of a simple mechanical model of planetary lithospheres and asthenospheres with recent experimental data for the brittle and ductile deformation of ice. For Ganymede, high surface gravity and warm temperatures render the achievement of an instability sufficiently great for the observed topographic relief virtually impossible; an instability of sufficient strength, however, may be able to develop on such smaller, colder bodies as Encedalus and Miranda. 15 refs

  19. SIIOS in Alaska - Testing an `In-Vault' Option for a Europa Lander Seismometer.

    Science.gov (United States)

    Bray, V. J.; Weber, R. C.; DellaGiustina, D. N.; Bailey, H.; Schmerr, N. C.; Pettit, E. C.; Dahl, P.; Albert, D.; Avenson, B.; Byrne, S.; Siegler, M.; Bland, M. T.; Patterson, G. W.; Selznick, S.

    2017-12-01

    The surface environment of Europa within the radiation-heavy jovian system, poses extreme technical challenges for potential landed missions. The need for radiation shielding and protection from the cold requires instruments to be housed within a thermally insulated and radiation protected `vault'. Unfortunately, this is non-ideal for seismometers as instrument-to-surface coupling is an important factor in the quality of returned data. Delivering a seismic package to an icy world would therefore benefit from the development of a cold-tolerant, radiation-hardened sensor that can survive outside of a protective vault. If such an instrument package were not technologically mature enough, or if lander safety considerations prevent deployment on lander legs, an in-vault location is still a viable option. For such a case, a better understanding of the transmission of seismic signals received through the lander legs is necessary for interpretation of the received signals. The performance, mass, and volume of the `Seismometer to investigate ice and ocean structure' (SIIOS) already meet or exceed flight requirements identified in lander studies for the icy moon Europa. We are testing this flight-candidate in several configurations around and within a lander mock-up, assuming a 1x1 meter vault with extended legs. We compare the received signals from a SIIOS device on the ice with those received by an identical sensor directly above it in the `vault'. We also compare the data from these single-point receivers to that received by two short base-line arrays - A 4-point "in-vault" array and another 4-point array arranged at the ice surface at the base of the lander legs. Our field-testing is performed at Gulkana Glacier, Alaska. The summer melt season provides kilometer-scale regions of coexisting ice, water, and silicate material, thereby providing seismic contrasts analogous to the ice-water layers and possible sub-surface lakes expected at Europa. We demonstrate the

  20. Slush Fund: The Multiphase Nature of Oceanic Ices and Its Role in Shaping Europa's Icy Shell

    Science.gov (United States)

    Buffo, J.; Schmidt, B. E.; Huber, C.

    2017-12-01

    The role of Europa's ice shell in mediating ocean-surface interaction, constraining potential habitability of the underlying hydrosphere, and dictating the surface morphology of the moon is discussed extensively in the literature, yet the dynamics and characteristics of the shell itself remain largely unconstrained. Some of the largest unknowns arise from underrepresented physics and varying a priori assumptions built into the current ice shell models. Here we modify and apply a validated one-dimensional reactive transport model designed to simulate the formation and evolution of terrestrial sea ice to the Europa environment. The top-down freezing of sea ice due to conductive heat loss to the atmosphere is akin to the formation of the Jovian moon's outer ice shell, albeit on a different temporal and spatial scale. Nevertheless, the microscale physics that govern the formation of sea ice on Earth (heterogenous solidification leading to brine pockets and channels, multiphase reactive transport phenomena, gravity drainage) likely operate in a similar manner at the ice-ocean interface of Europa, dictating the thermal, chemical, and mechanical properties of the ice shell. Simulations of the European ice-ocean interface at different stages during the ice shell's evolution are interpolated to produce vertical profiles of temperature, salinity, solid fraction, and eutectic points throughout the entire shell. Additionally, the model is coupled to the equilibrium chemistry package FREZCHEM to investigate the impact a diverse range of putative European ocean chemistries has on ice shell properties. This method removes the need for a priori assumptions of impurity entrainment rates and ice shell properties, thus providing a first principles constraint on the stratigraphic characteristics of a simulated European ice shell. These insights have the potential to improve existing estimates for the onset of solid state convection, melt lens formation due to eutectic melting, ice

  1. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  2. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  3. SATELLITE CONSTELLATION DESIGN PARAMETER

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. SATELLITE CONSTELLATION DESIGN PARAMETER. 1. ORBIT CHARACTERISTICS. ORBITAL HEIGHT >= 20,000 KM. LONGER VISIBILITY; ORBITAL PERIOD. PERTURBATIONS(MINIMUM). SOLAR RADIATION PRESSURE (IMPACTS ECCENTRICITY); LUNI ...

  4. Origen y filogenia de los primeros homínidos de Europa

    Directory of Open Access Journals (Sweden)

    A. Gómez

    2005-01-01

    Full Text Available Se discuten el origen y relaciones filogenéticas de la especie Homo antecesor, Bermudez de Castro et al.., 1997, con especial atención a los datos aportados por la nueva mandíbula recuperada en el nivel TD6 del yacimiento de Gran Dolina, en la Sierra de Atapuerca, que refuerzan la identidad taxonómica de esta especie y su relación con el origen de H. sapiens. Se constata la hipótesis de que H. antecessor represente el último antecesor común de los neandertales y de las poblaciones modernas y se considera la posibilidad de un origen asiático para el primer poblamiento de Europa

  5. Zweiwegintegration durch zweisprachige Bildung? Ergebnisse aus der Staatlichen Europa-Schule Berlin

    Science.gov (United States)

    Meier, Gabriela

    2012-06-01

    While there is no simple recipe of how to respond to the multitude of languages present in many European schools, this article presents a promising alternative to monolingual education. The focus is on Staatliche Europa-Schule Berlin (SESB), a two-way immersion (TWI) model that unites children whose mother tongue is German with children whose mother tongue is another locally spoken language in one class and teaches them together in two languages. Thus in this model, offered by 17 primary schools and 13 secondary schools in Berlin, pupils learn in two languages from and with each other. Based on a largely quantitative, quasi-experimental study with 603 students, evidence is provided that there are a number of peace-linguistic benefits that can promote two-way social integration, besides fostering personal and societal multilingualism. This suggests that TWI education as practised in Berlin could serve as an educational model for other multilingual parts of Europe.

  6. Las Comunidades Terapéuticas para el Tratamiento de la Drogodependencia en Europa

    OpenAIRE

    Paolo Stocco

    2008-01-01

    Después de una breve introduccción sobre el concepto de drogodependencia que se podría entender como un modo de auto curación y un modo errado de resolver problemas personales y de relación y después de brindar una visión panorámica sobre el consumo de sustancias en Europa, el artículo aborda el tema de los tratamientos de rehabilitación en las comunidades terapéuticas y brinda un panorama general sobre la evolución de los escenarios terapéuticos de los tratamientos residenciales en las com...

  7. Unión Europa: deudas soberanas y financiarización

    Directory of Open Access Journals (Sweden)

    Andrea Reyes

    2014-01-01

    Full Text Available Reseña al libro de Alicia Girón y Marcia Solorza, Europa, deudas soberanas y financiarización, IIEc-UNAM, México, D. F, 2012, ISBN 978-607 02-3977-9 La crisis de deuda que aqueja a la zona euro en los últimos años ha sido definida como la crisis más grave desde la Gran Depresión de 1929. La profundidad de la crisis, los graves problemas que trajo, pero sobre todo las fuertes medidas de austeridad en la zona euro como parte de la solución, obligan a un estudio más profundo y amplio de la crisis; ya que se trata de cambios de gran calado que se evidencian en las graves secuelas que ha impuesto la hegemonía del sistema financiero.

  8. Uso de las redes sociales en el sur de Europa. Género y adolescencia

    OpenAIRE

    Málaga Pescador, José Luis

    2017-01-01

    Investigamos en esta tesis el uso de las redes sociales virtuales entre los adolescentes (de 12 a 18 años) de tres países del sur de Europa: España, Italia y Portugal. En concreto se van a estudiar el nivel de penetración de estas redes, su utilización concreta, las pautas de acceso a internet y el uso del teléfono móvil, sus hábitos como clientes o consumidores y el papel de las redes en las actividades de socialización. La información proviene de una encuesta que se aplicó a una muestra de ...

  9. Europa en crisis: El desencanto de la Unión Europea

    Directory of Open Access Journals (Sweden)

    Stella Maris Shmite

    2014-01-01

    Full Text Available Las desigualdades y las tensiones sociales se manifiestan territorialmente en las ciudades europeas, las que se constituyen en espacios estratégicos donde se materializan las reivindicaciones sociales. La combinación del proceso de globalización y la organización institucional supranacional de Europa, junto a las profundas transformaciones que afectan la economía y por lo tanto, al sistema social característico del Estado de Bienestar, conducen a la emergencia de sentimientos de insatisfacción e incertidumbre que se expresan en los movimientos sociales. En este artículo se aborda el rol de la Unión Europea frente a la crisis, las respuestas institucionales, las consecuencias económicas y sociales y la emergencia de un cuestionamiento de la sociedad al funcionamiento de los Estados y la estructura supranacional.

  10. Modernizar la Agricultura: Una nueva corriente en europa y latinoamérica

    Directory of Open Access Journals (Sweden)

    Jairo Restrepo Rivera

    2001-11-01

    Full Text Available La incorporación de los procesos naturales de forma integral en las actividades agropecuarias de producción como son las relaciones simbíoticas de los ciclos minerales con el mundo vivo; la eliminación del uso de todos los insumos nocivos y practias que perjudiquen el medio ambiente , Ia salud de los trabajadores agrícolas y de los consumidores, relacionados con la mayor utilidad del potencial natural productivo, biológico de las plantas y de los animales asociadas al manejo de las unidades productivas de acuerdo con sus limitaciones, estan determinando Ia eficiencia y la viabilidad económica de Ia modernización de Ia agricultura en Europa y Latinoamérica, con énfasis en el manejo y conservación del suelo, del agua, de la energía y de los recursos naturales.

  11. Teoría social: Las relaciones entre Europa y Estados Unidos

    Directory of Open Access Journals (Sweden)

    JOSÉP PICÓ LÓPEZ

    1997-01-01

    Full Text Available la sociologia mundial perderia la comprension de su perspectiva y la variedad de sus enfoques respecto a la realidad social si continua sufriendo la estandarizacion de la sociologia profesional americana. la sociologia europea necesita resistir a esta tendencia de la misma manera en que europa ha de resistir la macdonalizacion de la cultura con el fin de preservar la diversidad de si misma y el mundo. contra esta tesis de r. münch, jeffrey c. alexander cuestiona la forma particular en que el sociologo aleman investiga la dimension social de la ciencia y el reduccionismo de su enfoque, es decir, la asimetria entre las causas sociales y la logica teorica en su analisis de la sociologia europea y americana. este articulo trata de situar, resumir y clarificar algunos de los temas de esta polemica teorica.

  12. LA RESPUESTA A LOS PELIGROS NATURALES Y AL CAMBIO CLIMÁTICO EN EUROPA

    Directory of Open Access Journals (Sweden)

    Philipp Schmidt-Thomé

    2009-01-01

    Full Text Available Los peligros naturales son la causa de desastres terribles y también la fuente de importantes ventajas naturales, por lo que desempeñan un papel crucial al crear tanto restricciones como oportunidades para el desarrollo territorial. Por lo pronto, si la comparamos con el resto del mundo, probablemente Europa no sea propensa a sufrir los efectos más catastróficos de los desastres, aunque este continente está afectado por algunos de los más considerables. En el presente estudio, se analizan los riesgos resultantes, incluidos los efectos potenciales del cambio climático en toda Europa, con el objeto de crear medidas adecuadas para sostener el desarrollo territorial. La ordenación territorial constituye un elemento destacado en la gestión de los riesgos y de las repercusiones del cambio climático. La creciente importancia de los peligros naturales en el entorno vital ha provocado un aumento de las prácticas nacionales de ordenación territorial en las últimas décadas y, en la actualidad, también centra la atención de la Unión Europea. Aquí examinamos unaincorporación más sólida de los peligros, los impactos del cambio climático y los riesgos resultantes en la ordenación territorial y en la gestión pública de los riesgos en el ámbito nacional y local y además esbozamos propuestas para el ámbito europeo.

  13. Waste management in a Europe in the process of unification; Abfallwirtschaft in einem zusammenwachsenden Europa

    Energy Technology Data Exchange (ETDEWEB)

    Hangen, H.O. [comp.

    1998-12-31

    In a Europe in the process of unification, waste management is an important and topical issue. Decisions in the environmental protection and waste management sectors are increasingly being taken in Brussels, at the European level, and no longer by national parliaments and governments. A unified economy calls for unified conditions of production. Environmental protection cannot stop at state frontiers.- The principle of waste disposal at short distance from the source of pollution, and the demand for Europe-wide tenders and contracts for services encompass a large field of tension, not only at first glance. The European sanitary landfills recommendation, valid also for the countries of the Mediterranean, and the ambitious aims of the technical code on municipal waste are an indication of the range of the economic and political issues due to arise at least transiently. The meeting should sharpen the problem awareness of persons involved with waste management and point out the dynamics of the process leading Europe into a unified waste management. (orig.) [Deutsch] Abfallwirtschaft in einem zusammenwachsenden Europa ist ein wichtiges und aktuelles Problem. Immer mehr Entscheidungen im Bereich des Umweltschutzes und der Abfallwirtschaft werden in Bruessel auf europaeischer Ebene und nicht mehr von den nationalen Parlamenten und Regierungen getroffen. Ein einheitlicher Wirtschaftsstandort verlangt auch einheitliche Produktionsbedingungen. Umweltschutz kann an Laendergrenzen nicht Halt machen. Das Prinzip der Naehe bei der Abfallbeseitigung und die Forderung der europaweiten Ausschreibung und Vergabe von Leistungen beinhaltet nicht nur auf den ersten Anschein ein grosses Spannungsfeld. Europaeische Deponierichtlinie, gueltig auch fuer die Laender des Mittelmeerraumes, und die hochgesteckten Ziele der TA-Siedlungsabfall zeigen die Spannweite und die wirtschaftliche und politische Problematik auf, die zumindest uebergangsweise auftritt. Die Tagung soll das

  14. Satellite Communications for ATM

    Science.gov (United States)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  15. [The Reception of Medieval Europa in the Baltic Sea Region. Papers of the XIIth Visby Symposium held at Gotland University, Visby] / Stefan Donecker

    Index Scriptorium Estoniae

    Donecker, Stefan, 1977-

    2011-01-01

    Arvustus : The Reception of Medieval Europa in the Baltic Sea Region. Papers of the XIIth Visby Symposium held at Gotland University, Visby. Viby : Gotland University Press, 2009. (Acta Visbyensia. 12)

  16. Thermally-Induced Chemistry and the Jovian Icy Satellites: A Laboratory Study of the Formation of Sulfur Oxyanions

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2011-01-01

    Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Here we present new results on thermally-induced reactions at 50-100 K in solid H2O-SO2 mixtures, reactions that take place without the need for a high-radiation environment. We find that H2O and SO2 react to produce sulfur Oxyanions, such as bisulfite, that as much as 30% of the SO2 can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at temperatures relevant to the icy satellites in the Jovian system.

  17. Mirada desde Europa, una encrucijada de los medios en América Latina y España: quando la Anaconda empieza a mudar la piel

    Directory of Open Access Journals (Sweden)

    Manuel Chaparro Escudero

    Full Text Available Pensar, escribir desde Europa, o sobre Europa obliga hoy a hacer la insidiosa observación de si Europa es capaz de mirar otra cosa que no sea así misma y si, además, tiene algo nuevo que decir. La Europa que soñamos, la Europa que sirvió de modelo a las llamadas sociedades democráticas se diluye en el dibujo de una sociedad más económica que social, más especulativa que solidaria. No es una afirmación ni gratuita, ni exagerada. Europa tiene poco que decir porque hace rato que perdió su brújula. Sólo los movimientos ciudadanos surgidos en el último año (entre ellos el 15-M sugieren un fin de ciclo de una forma de hacer política que se resiste a cambiar. Frente a esta situación América Latina empieza desde hace algunos años a ofrecer regulaciones de medios más comprometidas con los intereses ciudadanos.

  18. Satellite failures revisited

    Science.gov (United States)

    Balcerak, Ernie

    2012-12-01

    In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

  19. ESA's satellite communications programme

    Science.gov (United States)

    Bartholome, P.

    1985-02-01

    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  20. Solar Power Satellites

    CERN Document Server

    Flournoy, Don M

    2012-01-01

    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  1. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  2. Exobiology of icy satellites

    Science.gov (United States)

    Simakov, M. B.

    At the beginning of 2004 the total number of discovered planets near other stars was 119 All of them are massive giants and met practically in all orbits In a habitable zone from 0 8 up to 1 1 AU at less 11 planets has been found starting with HD 134987 and up to HD 4203 It would be naive to suppose existence of life in unique known to us amino-nucleic acid form on the gas-liquid giant planets Nevertheless conditions for onset and evolutions of life can be realized on hypothetical satellites extrasolar planets All giant planets of the Solar system have a big number of satellites 61 of Jupiter 52 of Saturn known in 2003 A small part of them consist very large bodies quite comparable to planets of terrestrial type but including very significant share of water ice Some from them have an atmosphere E g the mass of a column of the Titan s atmosphere exceeds 15 times the mass of the Earth atmosphere column Formation or capture of satellites is a natural phenomenon and satellite systems definitely should exist at extrasolar planets A hypothetical satellite of the planet HD 28185 with a dense enough atmosphere and hydrosphere could have biosphere of terrestrial type within the limits of our notion about an origin of terrestrial biosphere As an example we can see on Titan the largest satellite of Saturn which has a dense nitrogen atmosphere and a large quantity of liquid water under ice cover and so has a great exobiological significance The most recent models of the Titan s interior lead to the conclusion that a substantial liquid layer

  3. Search for microorganisms on Europa and Mars in relation with the evolution of intelligent behavior on other worlds

    International Nuclear Information System (INIS)

    Chela-Flores, Julian

    2001-11-01

    Within the context of how to search for life in the Solar System, we discuss the need to consider universal evolutionary biomarkers, in addition to those of biochemical nature that have already been selected for in the biology experiments of the old Viking and future Beagle-2 landers. For the wider problem of the evolution of intelligent behavior on other worlds (the SETI program), the type of experiments suggested below aim at establishing a direct connection between Solar System exploration and the first steps along the pathway toward the evolution of intelligent behavior. The two leading sites for the implementation of the proposed first whole-cell experiments would be, firstly, Europa after the Europa-Orbiter mission, either on the ice-crust, or in the ocean itself by means of a submersible; secondly, such experiments could be implemented once isolated liquid water oases are identified in the Martian substratum. (author)

  4. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  5. La Comunità Energetica del Sud Est Europa quale fattore di stabilità nell’area Balcanica

    OpenAIRE

    Massari, Saverio Francesco

    2012-01-01

    Il lavoro cerca di valutare il possibile ruolo della Comunità Energetica del Sud Est Europa quale fattore di stabilita’ nell’area Balcanica. Il Trattato fondativo della Comunita’ assegna a questa l’obiettivo di condurre una cooperazione in campo energetico al fine diffondere istituzioni e normative condivise, quali elementi di superamento del conflitto: tuttavia, sono molti gli ostacoli posti su questo cammino sia di natura interna alla regione che esterna, per l’influenza di fattori e poter...

  6. The Possibilities and Challenges in Missions to Europa and Titan for Exploration and as a Stepping Stone to Mankind

    Science.gov (United States)

    Ganapathy, Rohan M.

    This enthusiastic project describes a long-term development plan to enable human exploration of the outer solar system, with a focus on Europa and Titan. These are two of the most interesting moons of Jupiter and Saturn, respectively, because they are the places in the solar system with the greatest potential for harboring extraterrestrial life. Since human expeditions to these worlds are considered impossible with current capabilities, the proposal of a well-organized sequence of steps towards making this a reality is formulated. The project includes the necessary development strategies in key scientic and technological areas that are essential for identifying the requirements for the exploration of the outer planetary moons. Some of the topics that are analyzed throughout the project plan include: scientic observations at Europa and Titan, advanced propulsion and nuclear power systems, in-situ resource utilization, radiation mitigation techniques, closed life support systems, habitation for long-term space flight, and artificial gravity. In addition to the scientic and technological aspects of this project, it is recognized that before any research and development work may begin, some level of program management must be established. Within this paper, legal issues, national and international policy, motivation, organization and management, economic considerations, outreach, education, ethics, and social implications are all considered with respect to possible future scenarios which enable human missions to the outer solar system. This project illustrates how such accomplishments could influence a mission to Europa to search for evidence of life in its subsurface oceans. The future remains unpredictable, as does the realization of any of these possibilities. However, projects such as this remind us that the final frontier for humans is truly outer space, and only our imagination will determine where the frontier stops. We can dream of visiting other planetary

  7. The American Satellite Company (ASC) satellite deployed from payload bay

    Science.gov (United States)

    1985-01-01

    The American Satellite Company (ASC) communications satellite is deployed from the payload bay of the Shuttle Discovery. A portion of the cloudy surface of the earth can be seen to the left of the frame.

  8. An Examination of the Sagan-Coleman formula for application to planetary protection for Europa

    Science.gov (United States)

    Barengoltz, Jack

    2016-07-01

    The Sagan-Coleman formulafootnote{ Sagan, C.; Coleman, S. (1965). "Spacecraft sterilization standards and contamination of Mars". Journal of Astronautics and Aeronautics 3 (5): 22-27.} was originally published as a method to estimate the probability of contamination of Mars by a spacecraft. This estimate was required to satisfy the NASA planetary protection requirements for Mars, which were at the time specified in terms of a maximum allowed value for the probability of contamination. The form of the formula is: P{}_{c} = N{}_{0}{}_{ }P{}_{1}*P{}_{2}*....P{}_{n}*P{}_{g} Here P{}_{c}, the probability of contamination is the probability that one or more of N{}_{0} microbes on the spacecraft will survive to a release on the surface of Mars and reproduce. P{}_{g} is the probability of growth (reproduction, per microbe). Before the identification of the necessary parameters for a flight mission to Europa, it is worthwhile to clarify the mathematical origin of the formula. In fact, the phrase ``one or more'' of the N{}_{0}{}_{ }microbes provides{}_{ }a clue. The exact mathematical form is: [P_c=1-{(1-p)}^{N_0}] Here p is the probability per microbe that it will survive and grow, 1-p is the probability that it won't, {(1-p)}^{N_0} is the probability that all N{}_{0} microbes fail to survive and grow. Thus the last value subtracted from unity is the probability of ``one or more'' surviving and growing. For the case that N{}_{0} p factor (and possibly others) may not be used to demonstrate N{}_{0} p factors may not be automatically small enough to justify the approximation. The difference in the other two categories is subtler. It concerns the difference between a reduction factor that applies to all of the microbes as a group, versus a true probability per microbe. The former factors should multiply N{}_{0} in the exact formula; the latter factors should be included in the value of p. Fortunately, there is no effect in the approximate formula. There is again some effect in

  9. ¿Qué conceptos políticos para Europa?

    Directory of Open Access Journals (Sweden)

    Duso, Giuseppe

    2007-12-01

    Full Text Available This paper aims to face up the problem of the method in connection with the political concepts which are necessaries to think about Europa. That involves a philosophical- political reflection and a table of historical- conceptual orientation. Becomes also necessary the reference to an extensive critical work about modern political concepts, which raises questions about their supposed universality, but that manages at the same time to discuss with the thought of a long tradition which has in the Greek world her origin. It seems not possible to face up and to understand the problems which come up from the process that leads to the European Union with the concepts that have resulted in the State doctrine and that are the backbone of modern constitutions. These concepts are born in the heart of the doctrines of social contract and natural right and they are useful to a political form which has as inseparables poles the rights of individuals and the sovereignty of the political corps. Europe, because indeed of the plurality of the members which make her up, requires on the one hand the superseding of the concept of sovereignty of the States but on the other hand should not think about herself as a new sovereignty, or as a new and wider state magnitude. The superseding of the political conceptuality which is condensed in the sovereignty involves at the same time the fact of rethinking about those concepts —such as individual, equality, liberty— that, in the way in which have been thought starting from the modern iusnaturalism, appear as the logical foundations of sovereignty.

    Este texto se propone afrontar el problema del método en relación con los conceptos políticos necesarios para pensar Europa. Esto implica una reflexión de tipo filosófico- político y un cuadro de orientación histórico-conceptual. Se hace necesaria la referencia a un extenso trabajo crítico acerca de los conceptos políticos modernos que pone en cuestión su

  10. Water cycle and salinity dynamics in the mangrove forests of Europa and Juan de Nova Islands, southwest Indian Ocean.

    Science.gov (United States)

    Lambs, Luc; Mangion, Perrine; Mougin, Eric; Fromard, François

    2016-01-30

    The functioning of mangrove forests found on small coralline islands is characterized by limited freshwater inputs. Here, we present data on the water cycling of such systems located on Europa and Juan de Nova Islands, Mozambique Channel. In order to better understand the water cycle and mangrove growth conditions, we have analysed the hydrological and salinity dynamics of the systems by gauge pressure and isotopic tracing (δ18O and δ2H values). Both islands have important seawater intrusion as measured by the water level change and the high salinities in the karstic ponds. Europa Island displays higher salinity stress, with its inner lagoon, but presents a pluri-specific mangrove species formation ranging from shrub to forest stands. No freshwater signal could be detected around the mangrove trees. On Juan de Nova Island, the presence of sand and detrital sediment allows the storage of some amount of rainfall to form a brackish groundwater. The mangrove surface area is very limited with only small mono-specific stands being present in karstic depression. On the drier Europa Island, the salinity of all the water points is equal to or higher than that of the seawater, and on Juan de Nova the groundwater salinity is lower (5 to 20 PSU). This preliminary study shows that the karstic pothole mangroves exist due to the sea connection through the fractured coral and the high tidal dynamics.

  11. Radar attenuation in Europa's ice shell: Obstacles and opportunities for constraining the shell thickness and its thermal structure

    Science.gov (United States)

    Kalousová, Klára; Schroeder, Dustin M.; Soderlund, Krista M.

    2017-03-01

    Young surface and possible recent endogenic activity make Europa one of the most exciting solar system bodies and a primary target for spacecraft exploration. Future Europa missions are expected to carry ice-penetrating radar instruments designed to investigate its subsurface thermophysical structure. Several authors have addressed the radar sounders' performance at icy moons, often ignoring the complex structure of a realistic ice shell. Here we explore the variation in two-way radar attenuation for a variety of potential thermal structures of Europa's shell (determined by reference viscosity, activation energy, tidal heating, surface temperature, and shell thickness) as well as for low and high loss temperature-dependent attenuation model. We found that (i) for all investigated ice shell thicknesses (5-30 km), the radar sounder will penetrate between 15% and 100% of the total thickness, (ii) the maximum penetration depth varies laterally, with deepest penetration possible through cold downwellings, (iii) direct ocean detection might be possible for shells of up to 15 km thick if the signal travels through cold downwelling ice or the shell is conductive, (iv) even if the ice/ocean interface is not directly detected, penetration through most of the shell could constrain the deep shell structure through returns from deep non-ocean interfaces or the loss of signal itself, and (v) for all plausible ice shells, the two-way attenuation to the eutectic point is ≲30 dB which shows a robust potential for longitudinal investigation of the ice shell's shallow thermophysical structure.

  12. Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

    Science.gov (United States)

    2017-09-01

    programmed for eventual integration with the Iridium Network , which is then tested. C. THESIS ORGANIZATION The thesis addresses these questions...NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS by Faisal S. Alshaya September 2017 Co-Advisors: Steven J. Iatrou...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE LEVERAGING THE NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS 5

  13. Counterintuitive Constraints on Chaos Formation Set by Heat Flux through Europa's Ocean

    Science.gov (United States)

    Goodman, J. C.

    2013-12-01

    Models for the formation of disruptive chaos features on the icy surface of Europa fall into two broad categories: either chaos is formed when basal heating causes localized melting and thinning of the ice shell, or basal heating drives diapiric convection within the ice shell. We argue that in both of these cases, heating of the ice shell from below does not lead to chaos formation at the location of heating. If chaos is formed when a localized oceanic heat source, such as a hydrothermal plume, "melts through" the ice crust, we must consider what happens to the melted liquid. If Europa's ocean is salty, the melt will form a buoyant pool inside the melted cavity, leading to a stable interface between cold fresh meltwater and warm salty seawater. This stable interface acts like an ablative heat shield, protecting the ice from further damage. Some heat can be transferred across the stable layer by double diffusion, but this transfer is very inefficient. We calculate that local ocean heating cannot be balanced by local flux through the stable layer: instead, the warm ocean water must spread laterally until it is delivering heat to the ice base on a regional or global scale (a heating zone hundreds or thousands of km across, for conservative parameters.) If chaos is formed by diapiric solid-state convection within the ice shell, many investigators have assumed that diapirism and chaos should be most prevalent where the basal heat flux is strongest. We argue that this is not the case. In Rayleigh-Benard convection, increasing the heat flux will make convection more vigorous --- if and only if the convecting layer thickness does not change. We argue that increased basal heat flux will thin the ice shell, reducing its Rayleigh number and making convection less likely, not more. This insight allows us to reverse the logic of recent discussions of the relationship between ocean circulation and chaos (for instance, Soderlund et al, 2013 LPSC). We argue that global oceanic

  14. Política y secularización en la Europa contemporánea

    Directory of Open Access Journals (Sweden)

    Manuel ÁLVAREZ TARDÍO

    2010-02-01

    Full Text Available RESUMEN: Este trabajo se ocupa de la relación entre la política y los procesos de secularización en la Europa contemporánea, estudia sus variantes y opciones ideológicas, así como sus diferentes tradiciones y situaciones nacionales, poniendo de relieve la existencia de dos grandes modelos. El primero —el de Gran Bretaaña, Bélgica y Holanda— se caracterizó por su gradualismo, tras la renuncia por parte del bloque político secular a apropiarse del Estado y su aceptación de la idea de que éste debía limitarse a proteger la libertad inherente al individuo. En cambio, el modelo de laicismo estatista —vigente en Francia, Italia y, en su versión más extrema, en la España de la II República—, partía de la idea de que el Estado era intérprete absoluto de un poder que no puede fragmentarse sin dejar de ser democrático, y se tradujo en el intento de contrarrestar la presencia católica mediante la imposición de políticas laicas, especialmente en el ámbito de la educación. Palabras Clave: Historia Contemporánea de Europa, Religión, Política, Secularización, Laicismo. ABSTRACT: This study deals with the relationship between politics and secularization processes in contemporary Europe, and studies its ideological variants and options as well as its different national traditions and situations, emphasizing the existence of two large models. The first, that of Great Britain, Belgium and Holland, is characterized by its gradualism, after the secular political block renounced appropriation of the State and accepted the idea that the State should be limited to protecting the inherent freedom of the individual. However, the model of state laicism, prevailing in France, Italy and in its most extreme versión in the Spain of the Second Republic, was based on the idea that the State was the absolute interpreter of a power that could not be fragmented without becoming undemocratic, and was expressed in the attempt to counter Catholic

  15. Educational use assessment of Geomorphosites applied to the Picos de Europa National Park (Northern Spain)

    Science.gov (United States)

    Bazán, Héctor; Serrano, Enrique; Ruiz-Flaño, Purificación

    2014-05-01

    information have been applied after assess 51 geomorphosites in Picos de Europa. Applying the accessibility criteria, 15 geomorphosites have an educational value and so the educational assessment has been made. Each geomorphosite shows educational qualities for different topics and educational or leisure levels, all of them based in experiential education. The educational assessment sheets of geomorphosites allow greater accuracy of the didactic use in the National Park of the Picos de Europa and they are a tool to be used in the teaching task as well as leisure activities. The results permit to make use of the relief in educational curricula and develop leisure strategies to divulgation and interpretation of geomorphosites in NPA.

  16. Satellite Surveillance: Domestic Issues

    National Research Council Canada - National Science Library

    Best, Jr., Richard A; Elsea, Jennifer K

    2008-01-01

    ... and law enforcement purposes, in addition to the civil applications that have been supported for years. In 2007, it moved to transfer responsibility for coordinating civilian use of satellites to the Department of Homeland Security. The transfer occurred, however, apparently without notification of key congressional oversight committees.

  17. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  18. Hurricane Satellite (HURSAT) Microwave (MW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Hurricane Satellite (HURSAT) from Microwave (MW) observations of tropical cyclones worldwide data consist of raw satellite observations. The data derive from the...

  19. Satellite transmission of oceanographic data

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; Desai, R.G.P.; DeSa, E.J.

    Oceanographic data collected on a research vessel has been transmitted to a shore laboratory using the INMARSAT maritime satellite The system configuration used, consisted of Satellite Communication Terminals interfaced to desk top computers...

  20. Satellite Ocean Heat Content Suite

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and Information...

  1. Monitoring Cyanobacteria with Satellites Webinar

    Science.gov (United States)

    real-world satellite applications can quantify cyanobacterial harmful algal blooms and related water quality parameters. Provisional satellite derived cyanobacteria data and different software tools are available to state environmental and health agencies.

  2. Defense Meteorological Satellite Program (DMSP)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Defense Meteorological Satellite Program (DMSP) satellites collect visible and infrared cloud imagery as well as monitoring the atmospheric, oceanographic,...

  3. Surface Composition Near the Trailing Hemisphere Apex on Europa: The Manannán Impact Crater and Neighboring Terrain

    Science.gov (United States)

    Dalton, J. B.; Prockter, L. M.; Shirley, J. H.; Kamp, L.; Phillips, C. B.; Valenti, M.

    2012-12-01

    The Manannán impact crater and surrounding areas were imaged by Galileo's Near Infrared Mapping Spectrometer (NIMS) during the C3 orbital encounter. We have applied a linear mixture model based on cryogenic infrared reflectance spectroscopy to a "despiked" version of this NIMS observation (C3ENLINEA01A) to estimate abundances of sulfuric acid hydrate, hydrated sulfate salts, water ice and brines in surface exposures. Here we supplement our previously reported abundance estimates (Dalton et al., 2011) with additional results from our ongoing investigation. New geologic mapping precisely registered to the NIMS observation allows the extraction of high-quality near-infrared spectra specific to individual geologic units and morphological features. Detailed high resolution geologic mapping indicates the likely presence of extensive deposits of impact melt materials largely filling the crater floor (Moore et al. 2001), together with surrounding continuous ejecta deposits that may have been excavated from Europa's interior. We find that the crater floor and nearby ejecta exhibit low sulfuric acid abundance relative to the surroundings, with the abundance increasing with radial distance. Where the ejecta begins to thin and break up, the spectral mixture resembles a combination of pre-existing, high-acid-content materials and cleaner, excavated water ice. Several geologic units exhibit significantly lower sulfuric acid hydrate than expected for this region near the trailing hemisphere apex, varying from 53-64 wt% over the observation. This suggests that these surface units have received a reduced cumulative radiation dose (electrons and ions) compared to nearby terrain; this in turn implies geologic youth. We will present model compositions for several of Manannán's key stratigraphic units, including the crater floor deposits and the adjacent chaos and linea. We will interpret these results in the context of ongoing investigations of the interplay of exogenic and

  4. Telelibrary: Library Services via Satellite.

    Science.gov (United States)

    Liu, Rosa

    1979-01-01

    Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

  5. Brine Pockets in the Icy Shell on Europa: Distribution, Chemistry, and Habitability

    Science.gov (United States)

    Zolotov, M. Yu; Shock, E. L.; Barr, A. C.; Pappalardo, R. T.

    2004-01-01

    On Earth, sea ice is rich in brine, salt, and gas inclusions that form through capturing of seawater during ice formation. Cooling of the ice over time leads to sequential freezing of captured sea-water, precipitation of salts, exsolution of gases, and formation of brine channels and pockets. Distribution and composition of brines in sea ice depend on the rate of ice formation, vertical temperature gradient, and the age of the ice. With aging, the abundance of brine pockets decreases through downward migration. De- spite low temperatures and elevated salinities, brines in sea ice provide a habitat for photosynthetic and chemosynthetic organisms. On Europa, brine pockets and channels could exist in the icy shell that may be from a few km to a few tens of km thick and is probably underlain by a water ocean. If the icy shell is relatively thick, convection could develop, affecting the temperature pattern in the ice. To predict the distribution and chemistry of brine pockets in the icy shell we have combined numerical models of the temperature distribution within a convecting shell, a model for oceanic chemistry, and a model for freezing of Europan oceanic water. Possible effects of brine and gas inclusions on ice rheology and tectonics are discussed.

  6. SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA: THE DISTINCT SPECTRUM OF LARGE-SCALE CHAOS

    International Nuclear Information System (INIS)

    Fischer, P. D.; Brown, M. E.; Hand, K. P.

    2015-01-01

    We present a comprehensive analysis of spatially resolved moderate spectral resolution near-infrared spectra obtained with the adaptive optics system at the Keck Observatory. We identify three compositionally distinct end member regions: the trailing hemisphere bullseye, the leading hemisphere upper latitudes, and a third component associated with leading hemisphere chaos units. We interpret the composition of the three end member regions to be dominated by irradiation products, water ice, and evaporite deposits or salt brines, respectively. The third component is associated with geological features and distinct from the geography of irradiation, suggesting an endogenous identity. Identifying the endogenous composition is of particular interest for revealing the subsurface composition. However, its spectrum is not consistent with linear mixtures of the salt minerals previously considered relevant to Europa. The spectrum of this component is distinguished by distorted hydration features rather than distinct spectral features, indicating hydrated minerals but making unique identification difficult. In particular, it lacks features common to hydrated sulfate minerals, challenging the traditional view of an endogenous salty component dominated by Mg-sulfates. Chloride evaporite deposits are one possible alternative

  7. A Physical Model of the Proton Radiation Belts of Jupiter inside Europa's Orbit

    Science.gov (United States)

    Nénon, Q.; Sicard, A.; Kollmann, P.; Garrett, H. B.; Sauer, S. P. A.; Paranicas, C.

    2018-05-01

    A physical model of the Jovian trapped protons with kinetic energies higher than 1 MeV inward of the orbit of the icy moon Europa is presented. The model, named Salammbô, takes into account the radial diffusion process, the absorption effect of the Jovian moons, and the Coulomb collisions and charge exchanges with the cold plasma and neutral populations of the inner Jovian magnetosphere. Preliminary modeling of the wave-particle interaction with electromagnetic ion cyclotron waves near the moon Io is also performed. Salammbô is validated against in situ proton measurements of Pioneer 10, Pioneer 11, Voyager 1, Galileo Probe, and Galileo Orbiter. A prominent feature of the MeV proton intensity distribution in the modeled area is the 2 orders of magnitude flux depletion observed in MeV measurements near the orbit of Io. Our simulations reveal that this is not due to direct interactions with the moon or its neutral environment but results from scattering of the protons by electromagnetic ion cyclotron waves.

  8. An Approach to Searching for Life on Mars, Europa, and Enceladus

    Science.gov (United States)

    McKay, Christopher P.

    2008-03-01

    Near-term missions may be able to access samples of organic material from Mars, Europa, and Enceladus. The challenge for astrobiology will be to determine if this material is the remains of dead microorganisms or merely abiotic organic material. The remains of life that shares a common origin with life on Earth will be straightforward to detect using sophisticated methods such as DNA amplification. These methods are extremely sensitive but specific to Earth-like life. Detecting the remains of alien life—that does not have a genetic or biochemical commonality with Earth life—will be much more difficult. There is a general property of life that can be used to determine if organic material is of biological origin. This general property is the repeated use of a few specific organic molecules for the construction of biopolymers. For example, Earth-like life uses 20 amino acids to construct proteins, 5 nucleotide bases to construct DNA and RNA, and a few sugars to construct polysaccharides. This selectivity will result in a statistically anomalous distribution of organic molecules distinct from organic material of non-biological origin. Such a distinctive pattern, different from the pattern of Earth-like life, will be persuasive evidence for a second genesis of life.

  9. SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA: THE DISTINCT SPECTRUM OF LARGE-SCALE CHAOS

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P. D.; Brown, M. E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Hand, K. P., E-mail: pfischer@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-11-15

    We present a comprehensive analysis of spatially resolved moderate spectral resolution near-infrared spectra obtained with the adaptive optics system at the Keck Observatory. We identify three compositionally distinct end member regions: the trailing hemisphere bullseye, the leading hemisphere upper latitudes, and a third component associated with leading hemisphere chaos units. We interpret the composition of the three end member regions to be dominated by irradiation products, water ice, and evaporite deposits or salt brines, respectively. The third component is associated with geological features and distinct from the geography of irradiation, suggesting an endogenous identity. Identifying the endogenous composition is of particular interest for revealing the subsurface composition. However, its spectrum is not consistent with linear mixtures of the salt minerals previously considered relevant to Europa. The spectrum of this component is distinguished by distorted hydration features rather than distinct spectral features, indicating hydrated minerals but making unique identification difficult. In particular, it lacks features common to hydrated sulfate minerals, challenging the traditional view of an endogenous salty component dominated by Mg-sulfates. Chloride evaporite deposits are one possible alternative.

  10. Discursos sobre la identidad como recurso adaptativo entre inmigrantes colombianos en Europa

    Directory of Open Access Journals (Sweden)

    Gregorio Hernández Pulgarín

    2016-01-01

    Full Text Available Este artículo busca comprender el papel de los discursos que integran la identidad nacional en el proceso de adaptación en condiciones límite de inmigrantes colom - bianos en Europa. El abordaje, parte de un estudio etnográfico de colombianos inmigrantes por razones económicas en Bordeaux, Francia y Sevilla, España en di - ferentes períodos, de 2006 a 2012, y de la aplicación de entrevistas a migrantes colombianos en ambos países, retornados a Pereira, Colombia. Los resultados ob - tenidos muestran que en las situaciones límite, los inmigrantes colombianos suelen responder a los retos del proceso de adaptación, basados en discursos sobre la iden - tidad nacional que producen un efecto performativo con consecuencias favorables para la concepción de sí mismos, para la adaptación a las circunstancias adversas y para continuar el proyecto migratorio.

  11. Infrared Astronomy Satellite

    Science.gov (United States)

    Ferrera, G. A.

    1981-09-01

    In 1982, the Infrared Astronomy Satellite (IRAS) will be launched into a 900-km sun-synchronous (twilight) orbit to perform an unbiased, all-sky survey of the far-infrared spectrum from 8 to 120 microns. Observations telemetered to ground stations will be compiled into an IR astronomy catalog. Attention is given the cryogenically cooled, 60-cm Ritchey-Chretien telescope carried by the satellite, whose primary and secondary mirrors are fabricated from beryllium by means of 'Cryo-Null Figuring'. This technique anticipates the mirror distortions that will result from cryogenic cooling of the telescope and introduces dimensional compensations for them during machining and polishing. Consideration is also given to the interferometric characterization of telescope performance and Cryo/Thermal/Vacuum simulated space environment testing.

  12. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements....

  13. Thematic mapping from satellite imagery

    CERN Document Server

    Denègre, J

    2013-01-01

    Thematic Mapping from Satellite Imagery: A Guidebook discusses methods in producing maps using satellite images. The book is comprised of five chapters; each chapter covers one stage of the process. Chapter 1 tackles the satellite remote sensing imaging and its cartographic significance. Chapter 2 discusses the production processes for extracting information from satellite data. The next chapter covers the methods for combining satellite-derived information with that obtained from conventional sources. Chapter 4 deals with design and semiology for cartographic representation, and Chapter 5 pre

  14. Cooperative and cognitive satellite systems

    CERN Document Server

    Chatzinotas, Symeon; De Gaudenzi, Riccardo

    2015-01-01

    Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

  15. Satellite Photometric Error Determination

    Science.gov (United States)

    2015-10-18

    Satellite Photometric Error Determination Tamara E. Payne, Philip J. Castro, Stephen A. Gregory Applied Optimization 714 East Monument Ave, Suite...advocate the adoption of new techniques based on in-frame photometric calibrations enabled by newly available all-sky star catalogs that contain highly...filter systems will likely be supplanted by the Sloan based filter systems. The Johnson photometric system is a set of filters in the optical

  16. Performance of OSC's initial Amtec generator design, and comparison with JPL's Europa Orbiter goals

    International Nuclear Information System (INIS)

    Schock, A.; Noravian, H.; Or, C.; Kumar, V.

    1998-01-01

    The procedure for the analysis (with overpotential correction) of multitube AMTEC (Alkali Metal Thermal-to-Electrical Conversion) cells described in Paper IECEC 98-243 was applied to a wide range of multicell radioisotope space power systems. System design options consisting of one or two generators, each with 2, 3, or 4 stacked GPHS (General Purpose Heat Source) modules, identical to those used on previous NASA missions, were analyzed and performance-mapped. The initial generators analyzed by OSC had 8 AMTEC cells on each end of the heat source stack, with five beta-alumina solid electrolyte (BASE) tubes per cell. The heat source and converters in the Orbital generator designs are embedded in a thermal insulation system consisting of Min-K fibrous insulation surrounded by graded-length molybdenum multifoils. Detailed analyses in previous Orbital studies found that such an insulation system could reduce extraneous heat losses to about 10%. For the above design options, the present paper presents the system mass and performance (i.e., the EOM system efficiency and power output and the BOM evaporator and clad temperatures) for a wide range of heat inputs and load voltages, and compares the results with JPL's preliminary goals for the Europa Orbiter mission to be launched in November 2003. The analytical results showed that the initial 16-cell generator designs resulted in either excessive evaporator and clad temperatures and/or insufficient power outputs to meet the JPL-specified mission goals. The computed performance of modified OSC generators with different numbers of AMTEC cells, cell diameters, cell lengths, cell materials, BASE tube lengths, and number of tubes per cell are described in Paper IECEC.98.245 in these proceedings

  17. L'integrazione delle pratiche di Sanitá Pubblica in Europa

    Directory of Open Access Journals (Sweden)

    H. Waller

    2003-05-01

    Full Text Available

    Rilevanza dell’argomento: questo tema è diventato un importante problema di Sanità Pubblica anche in Europa. Studi epidemiologici mostrano che quasi tutti i problemi di salute e la prevalenza di malattie e di disabilità sono più frequenti negli strati sociali più bassi, indipendentemente dal modo in cui la classe sociale viene misurata (con qualche eccezione come ad esempio il cancro della mammella e le allergie. Inoltre, l’associazione tra svantaggio sociale e malattia è divenuta sempre più forte negli ultimi decenni (Marmot e Wilkinson, 1999.

     La rilevanza del tema è diventata ancora più grande dal momento che in molti Paesi candidati all’ingresso nell’Unione Europea sono frequenti povertà e disgregazione sociale (Mackenbach e Bakker, 2002. Future necessita’ di ricerca: in futuro, tutte le indagini nazionali sulla salute dovranno includere la classe sociale tra le variabili registrate regolarmente. La ricerca dovrà infatti concentrarsi sulla spiegazione della correlazione tra classe sociale e malattia usando studi longitudinali ed includendo fattori sociali, oltre a determinanti medico-sanitari.

    La correlazione tra classe sociale e la presenza di problemi di salute va studiata in entrambe le direzioni: un basso status sociale come determinante di malattia, come pure la presenza di problemi di salute come causa della discesa nella “scala sociale”. La pratica di Sanità Pubblica e lo sviluppo di politiche sociali devono affrontare adeguatamente entrambe le ipotesi.

  18. EXTENSÃO UNIVERSITÁRIA NA EUROPA: A TERCEIRA MISSÃO

    Directory of Open Access Journals (Sweden)

    Pedro Nunes Teixeira

    2015-04-01

    Full Text Available In many countries, interest in greater openness and integration of universities to social and economic environment is growing. Driven by society and the knowledge economy and the social demands, the University Extension has gained increasing importance, both in Latin America where the main focus is on direct social actions, interventions promoting citizenship and fomenting local leadership, whether in developed economies where services and technology transfer receive greater attention. In continental Europe the term correlate to the most widely adopted extension is "Third Mission", and is subdivided into three sub-areas: Continuing Education, Technology Transfer and Innovation, and Social Engagement. This Academy playing field also gains strength in the "old continent".Em vários países, o interesse por maior abertura e integração das universidades ao meio social e econômico é crescente. Impulsionada pela sociedade e economia do conhecimento e pelas demandas sociais, a Extensão Universitária ganha cada vez mais importância, seja na América Latina onde o foco principal são ações sociais diretas, intervenções promotoras da cidadania e fomentadoras do protagonismo local, seja em economias mais desenvolvidas onde os serviços e a transferência de tecnologia recebem maior atenção. Na Europa continental o termo correlato à extensão mais adotado é “Terceira Missão” (Third Mission1, e subdivide-se em três sub-áreas: Educação Continuada, Transferência de Tecnologia e Inovação, e Engajamento Social. Este campo de atuação da academia também ganha força no “velho continente”.

  19. Mobile satellite service communications tests using a NASA satellite

    Science.gov (United States)

    Chambers, Katherine H.; Koschmeder, Louis A.; Hollansworth, James E.; ONeill, Jack; Jones, Robert E.; Gibbons, Richard C.

    1995-01-01

    Emerging applications of commercial mobile satellite communications include satellite delivery of compact disc (CD) quality radio to car drivers who can select their favorite programming as they drive any distance; transmission of current air traffic data to aircraft; and handheld communication of data and images from any remote corner of the world. Experiments with the enabling technologies and tests and demonstrations of these concepts are being conducted before the first satellite is launched by utilizing an existing NASA spacecraft.

  20. La criminalità organizzata nell'Europa Centro-Orientale dopo il 1989. Una prospettiva geopolitica

    Directory of Open Access Journals (Sweden)

    Stefan Bielański

    2017-08-01

    Full Text Available L’articolo riguarda lo sfondo geopolitico e i meccanismi della criminalità organizzata nell’Europa centro-orientale. L’autore presenta le caratteristiche principali della situazione geopolitica in quella regione dopo la dissoluzione dell’Unione Sovietica. La sua attenzione è rivolta in particolare alla nascita, alla struttura e alle modalità di funzionamento della criminalità organizzata sulla nuova frontiera orientale dell’Unione europea. In tal senso si sofferma sui rapporti tra la criminalità organizzata e il nuovo terrorismo indicandone il pericolo per la stabilità sociale, politica ed economica dell’Europa centro-orientale. Similmente agli studiosi ed esperti polacchi egli indica il rischio, di una “evoluzione” della criminalità organizzata al terrorismo, sostenendo che le autorità degli stati europei debbano tenerne conto con la massima responsabilità per la sicurezza dei loro paesi e dei loro cittadini. Parole chiave: Geopolitica, Europa centro-orientale, Unione europea, Criminalità organizzata, Terrorismo   The paper concerns the geopolitical background of the emergence and functioning of organized crime in Central-East Europe. The author outlines the main characteristics of the geopolitical situation of the region after the transformation. A special focus is given to the rise, structure and operational manners of organized crime at the new, eastern border of EU. Eventually the author considers the relations between organized crime and new terrorism, acknowledging both these phenomena as a threat towards social, political and economic stability in the Central-East Europe. Likewise to several Polish scholars and experts, the author recognizes the patterns of the highly dangerous process of organized crime's evolution into terrorism. The author emphasizes that authorities of the European states must take into account both dangers as deeply relevant issue for security of their countries and citizens. Keywords

  1. Escenarios de la migración latinoamericana: la vida familiar transnacional entre Europa y América Latina

    OpenAIRE

    Isabel Yepez del Castillo

    2014-01-01

    Este artículo tiene tres partes, en la primera pasamos revista a las migraciones entre Europa y América Latina desde una perspectiva de larga duración destacando las incidencias de la globalización en el aumento de las desigualdades entre países y en los procesos de movilidad social ascendente y descendente de las familias migrantes. En la segunda, abordamos los escenarios posibles y estrategias múltiples de la presencia latinoamericana en la Unión Europea en el contexto de crisis global. Fin...

  2. Surface composition of pull-apart bands in Argadnel Regio, Europa: Evidence of localized cryovolcanic resurfacing during basin formation

    Science.gov (United States)

    Prockter, Louise M.; Shirley, James H.; Dalton, James B.; Kamp, L.

    2017-03-01

    We combine Galileo Solid State Imager (SSI) and Near-Infrared Mapping Spectrometer (NIMS) data to investigate the composition of pull-apart bands in Europa's Argadnel Regio. Using spectral linear mixture modeling employing cryogenic laboratory reference spectra, we find that bands of intermediate age ("grey" bands) are compositionally distinct from bands that are stratigraphically younger ("dark" bands). The grey bands have higher abundances of larger ice grains and lower abundances of hydrated salts than the dark bands; both of these tendencies are statistically significant at the 1% level. The grey and dark bands have similar abundances of hexahydrite, a material which is relatively stable under irradiation; however, the derived abundances of frozen magnesium sulfate brine and of mirabilite, which are more susceptible to fragmentation by radiation, are significantly higher in the dark bands than in the grey bands. These results are consistent with a physical model in which the differences in composition and in ice grain sizes are linked to space weathering and radiolytic processing levels; the grey bands have presumably undergone higher levels of processing, due to being exposed on Europa's surface for a longer period of time. One prominent wedge-shaped band exhibits an anomalous albedo variation across its northern portion, appearing dark in its top third, and grey in its southernmost two-thirds. We find that the dark part of the band has a modeled composition that is in-family with other dark bands, while the grey portion has a modeled composition that is indistinguishable from other grey bands in the study area. Because these variations cannot easily be attributed to the band's formation mechanism (bands open sequentially along a central axis), we surmise that the northern part has been resurfaced, probably in response to the formation of a large topographic basin that cuts through the band. Faulting accompanying basin formation may provide conduits allowing

  3. Una visión comparada de la vivienda social en europa. El caso de Barcelona y Londres

    OpenAIRE

    Arends Morales, Lenimar Nairt; Garcia-Almirall, M. Pilar

    2014-01-01

    La política de vivienda en Europa está caracterizada por la diversidad, no existe un modelo único de gestión de la vivienda o de concepto de vivienda social. Cada país tiene sus propios criterios para enfrentar el problema de la vivienda, y se encuentran distintas visiones de gestión en relación a la población a atender, el régimen de tenencia, el tamaño de las viviendas, entre otros. Esta diferencia de enfoques está relacionada con los diferentes modelos del Estado de Bienestar (Arbaci, 2007...

  4. Marco jurídico y principales instrumentos de la cooperación transfronteriza institucional en Europa

    OpenAIRE

    Medina García, Eusebio

    2017-01-01

    En este artículo realizamos un recorrido desde los orígenes de la «cooperación transfronteriza institucional» en Europa hasta la actual «cooperación territorial». Definimos y comparamos los conceptos de «cooperación institucional» y «cooperación tradicional” y auguramos un acercamiento entre ambas. Describimos el principal marco legal de la «cooperación transfronteriza institucional» y analizamos sus principales instrumentos, prestando una atención especial a la Eurorregión, a la Agrupación E...

  5. Integrated energy data solution for energy markets of Europe: Energy Data Warehouse; Integrierte Energiedatenloesung fuer Europas Energiemaerkte: Energy Data Warehouse

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-07-01

    According to Ralf Hoffmann, head of the sales department of Goerlitz Computerbau AG, integrated problem solutions for Europe's new energy markets must be developed fast, without delay and with all efforts available. [German] 'Integrierte Problemloesungen fuer Europas neue Energiemaerkte muessen schnell und investitionssicher fuer die Anwender realisiert werden. Sie dulden keinen Aufschub. Alle unternehmerische Kraft muss und wird in die Befriedigung dieser Anforderungen gelegt.' So aeussert sich der Vorstand Absatzwirtschaft der Goerlitz Computerbau AG, Ralf Hoffmann. (orig.)

  6. Effects of drastic climate policy on air pollution in Europe; Effecten van vergaand klimaatbeleid op luchtverontreiniging in Europa

    Energy Technology Data Exchange (ETDEWEB)

    Koelemeijer, R. [Planbureau voor de Leefomgeving PBL, Den Haag (Netherlands); ; Sauter, F.; Posch, M. [Rijksinstituut voor Volksgezondheid en Milieu RIVM, Bilthoven (Netherlands); Chuwah, C. [Koninklijk Nederlands Meteorologisch Instituut KNMI, De Bilt (Netherlands)

    2012-08-15

    Greenhouse gas emissions in Europe need to be lowered by 80-95% in 2050 compared to 1990 to curb global warming to 2°C. This article addresses the consequences for air quality of various ways to realize such a drastic emission reduction [Dutch] Emissies van broeikasgassen in Europa moeten in 2050 80-95% lager zijn dan in 1990 om de opwarming van de aarde te beperken tot 2C. Dit artikel gaat in op de consequenties voor de luchtkwaliteit van verschillende manieren om zo'n vergaande emissiereductie te realiseren.

  7. Satellite disintegration dynamics

    Science.gov (United States)

    Dasenbrock, R. R.; Kaufman, B.; Heard, W. B.

    1975-01-01

    The subject of satellite disintegration is examined in detail. Elements of the orbits of individual fragments, determined by DOD space surveillance systems, are used to accurately predict the time and place of fragmentation. Dual time independent and time dependent analyses are performed for simulated and real breakups. Methods of statistical mechanics are used to study the evolution of the fragment clouds. The fragments are treated as an ensemble of non-interacting particles. A solution of Liouville's equation is obtained which enables the spatial density to be calculated as a function of position, time and initial velocity distribution.

  8. Do asteroids have satellites

    International Nuclear Information System (INIS)

    Weidenschilling, S.J.; Paolicchi, P.; Zappala, V.

    1989-01-01

    A substantial body of indirect evidence suggests that some asteroids have satelities, although none has been detected unambiguously. Collisions between asteroids provide physically plausible mechanisms for the production of binaries, but these operate with low probability; only a small minority of asteroids are likely to have satellites. The abundance of binary asteroids can constrain the collisional history of the entire belt population. The allowed angular momentum of binaries and their rate of tidal evolution limit separations to no more than a few tens of the primary's radii. Their expected properties are consistent with failure to detect them by current imaging techniques

  9. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  10. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  11. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  12. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication sa...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  13. Agent control of cooperating satellites

    OpenAIRE

    Lincoln, N.K.; Veres, S.M.; Dennis, Louise; Fisher, Michael; Lisitsa, Alexei

    2011-01-01

    A novel, hybrid, agent architecture for (small)swarms of satellites has been developed. The software architecture for each satellite comprises ahigh-level rational agent linked to a low-level control system. The rational agent forms dynamicgoals, decides how to tackle them and passes theactual implementation of these plans to the control layer. The rational agent also has access to aMatLabmodel of the satellite dynamics, thus allowing it to carry out selective hypothetical reasoningabout pote...

  14. Condiciones de trabajo saludables. Análisis de los estudios realizados en Colombia y Europa en el periodo 2002-2012

    OpenAIRE

    Leal Mejia, Carolina

    2013-01-01

    INTRODUCCIÓN. El presente trabajo explora las condiciones de trabajo saludables más frecuentemente estudiadas en Colombia y Europa en el período 2002 a 2012. OBJETIVO. Este trabajo busca definir los avances en investigación de las condiciones de trabajo saludables que presentaron Colombia y Europa en el período 2002 a 2012, a través de: el análisis del concepto de salud en el trabajo desde diferentes enfoques e investigaciones; el análisis los modelos sobre condiciones saludables en el trabaj...

  15. "Cy Twombly: Intérprete de dos mundos" [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo

    OpenAIRE

    Gras Cruz, Irene

    2017-01-01

    Esta tesis “Cy Twombly: Intérprete de dos mundos” [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo] pretende dar a conocer al artista norteamericano Cy Twombly (1928-2011) en nuestro país y destacar la importancia que tiene dentro del panorama artístico como figura clave en un momento de efervescencia —artística y creativa— americana en el que a diferencia de sus coetáneos prefirió emigrar a Europa, concretamente a Italia. Mientras todos se trasladaban a la nueva...

  16. Detención de menores extranjeros no acompañados en Europa: la necesidad de garantizar efectivamente los derechos ya reconocidos

    Directory of Open Access Journals (Sweden)

    Juan Manuel López Ulla

    Full Text Available El Consejo de Europa y la Unión Europea, en varios documentos aprobados entre 2010 y 2012, reconocen abiertamente que en Europa no se han adoptado las medidas suficientes para garantizar de manera efectiva los derechos reconocidos en la Convención de Naciones Unidas sobre los Derechos del Niño (1989 en relación con los menores extranjeros no acompañados. Por lo que se refiere a las condiciones en las que pueden ser detenidos, urge implementar un procedimiento común capaz de salvaguardar la tutela administrativa y jurisdiccional de estos menores.

  17. Sistema solar para aquecimento ambiente e aquecimento de piscinas: uma solução promissora para climas do Sul da Europa

    OpenAIRE

    Carvalho, M. J.; Neves, Ana

    2006-01-01

    A avaliação do sistema apresentado neste trabalho foi focada em sistemas que podem fornecer água quente, aquecimento ambiente e aquecimento de piscinas, e que são projectados para climas do Sul da Europa, especialmente para habitações uni-familiares. Pelas características climáticas do Sul da Europa, o aquecimento ambiente é apenas necessário para um curto período do ano, sendo para esta avaliação considerado um período de seis meses para aquecimento ambiente e um período de seis meses para a...

  18. Trends in mobile satellite communication

    Science.gov (United States)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  19. Magnetic Satellite Missions and Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Kotsiaros, Stavros

    2011-01-01

    Although the first satellite observations of the Earth’s magnetic field were already taken more than 50 years ago, continuous geomagnetic measurements from space are only available since 1999. The unprecedented time-space coverage of this recent data set opened revolutionary new possibilities...... for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...... exploration of Earth’s magnetic field with satellites....

  20. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    Science.gov (United States)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  1. Spectroscopy and viability of Bacillus subtilis spores after ultraviolet irradiation: implications for the detection of potential bacterial life on Europa.

    Science.gov (United States)

    Noell, Aaron C; Ely, Tucker; Bolser, Diana K; Darrach, Halley; Hodyss, Robert; Johnson, Paul V; Hein, Jeffrey D; Ponce, Adrian

    2015-01-01

    One of the most habitable environments in the Solar System outside of Earth may exist underneath the ice on Europa. In the near future, our best chance to look for chemical signatures of a habitable environment (or life itself) will likely be at the inhospitable icy surface. Therefore, it is important to understand the ability of organic signatures of life and life itself to persist under simulated europan surface conditions. Toward that end, this work examined the UV photolysis of Bacillus subtilis spores and their chemical marker dipicolinic acid (DPA) at temperatures and pressures relevant to Europa. In addition, inactivation curves for the spores at 100 K, 100 K covered in one micron of ice, and 298 K were measured to determine the probability for spore survival at the surface. Fourier transform infrared spectra of irradiated DPA showed a loss of carboxyl groups to CO2 as expected but unexpectedly showed significant opening of the heterocyclic ring, even for wavelengths>200 nm. Both DPA and B. subtilis spores showed identical unknown spectral bands of photoproducts after irradiation, further highlighting the importance of DPA in the photochemistry of spores. Spore survival was enhanced at 100 K by ∼5× relative to 298 K, but 99.9% of spores were still inactivated after the equivalent of ∼25 h of exposure on the europan surface.

  2. International Satellite Law

    Science.gov (United States)

    von der Dunk, Frans

    2017-07-01

    there are the major categories of space applications—as these have started to impact everyday life on earth: the involvement of satellites in communications infrastructures and services, the most commercialized area of space applications yet; the special issue of space serving to mitigate disasters and their consequences on earth; the use of satellites for remote sensing purposes ranging from weather and climate monitoring to spying; and the use of satellites for positioning, navigation, and timing.

  3. The Future of Satellite Communications Technology.

    Science.gov (United States)

    Nowland, Wayne

    1985-01-01

    Discusses technical advances in satellite technology since the 1960s, and the International Telecommunications Satellite Organization's role in these developments; describes how AUSSAT, Australia's domestic satellite system, exemplifies the latest developments in satellite technology; and reviews satellite system features, possible future…

  4. Las desigualdades educativas en Europa : una cuestión de actualidad

    Directory of Open Access Journals (Sweden)

    Marie Duru-Bellat

    2010-01-01

    Full Text Available Este texto analiza el progreso de las políticas educativas europeas, precisamente en un período de crisis económica cuando las preocupaciones por la eficiencia se ponen de relieve con más facilidad y se trasladan al ámbito educativo donde consiguen una atención privilegiada. Relanzar el crecimiento exigiría invertir masivamente en la enseñanza superior para estimular la innovación, y también desarrollar intensamente la formación de adultos, especialmente en sectores de población menos cualificados, con menor nivel de instrucción y más expuestos a los riesgos del paro y a las exigencias de reestructuración. En este sentido, Europa no ha esperado al periodo de crisis actual para hacer de la educación un instrumento de una política económica competitiva global. Así surge la Estrategia de Lisboa, en el año 2000. Además durante los últimos años, el objetivo de reforzar la cohesión social ha cobrado cada vez más importancia, llegando a convertirse en complemento del objetivo prioritario de eficacia económica. En la última parte, aborda de forma amplia el alcance de las políticas escolares en este contexto.This text analyzes the progress of European education policies, precisely at a time of economic crisis when efficiency concerns are more easily highlighted, and relocated into the educational environment wherethey get privileged attention. To strengthen growth would require massiveinvestment in higher education in orderto stimulate innovation, as well asdeveloping adult training intensely, especially in areas of population that are less qualified, less educated and more exposed to the risks of unemployment and the demands for restructuring.In this regard, Europe has not waited for the arrival oftoday´s current crisis period to make education an instrument of global competitive economic policies. Thus arises the Lisbon Strategy in 2000. Also in recent years, the goal of strengthening social cohesion has become increasingly

  5. L’INSEGNAMENTO DELLE SCIENZE IN EUROPA: ASPETTI LINGUISTICI A CONFRONTO (ITALIA, DANIMARCA, GALLES

    Directory of Open Access Journals (Sweden)

    Silvia Marianna Bollone

    2015-02-01

    Full Text Available La componente linguistica riveste un ruolo prioritario nell’insegnamento-apprendimento delle scienze, specificamente prescritto dai programmi scolastici attualmente vigenti in Europa e pienamente accolto dalle Indicazioni nazionali per il curricolo della scuola dell'infanzia e del primo ciclo d’istruzione, di cui D.M. 254/2012. Il presente lavoro intende indagare l’incidenza dell’aspetto linguistico-comunicativo nel processo di insegnamento-apprendimento delle scienze nell’ambito di tre differenti contesti europei: l’Italia, la Danimarca e il Galles, nella fascia di età compresa all’incirca tra gli 11 e 14 anni, corrispondente per l’Italia alla Scuola secondaria di primo grado, per la Danimarca ad un segmento della Folkeskole, e per il Galles alla fase iniziale della Secondary School. La ricerca, incentrata su uno specifico argomento del programma di scienze comune ai tre sistemi scolastici, prevede un’analisi dei programmi ministeriali, delle programmazioni degli insegnanti, dei manuali in uso nelle scuole, nell’intento di definire il ruolo assegnato agli aspetti linguistici nell’insegnamento delle scienze sia livello legislativo-istituzionale che nella quotidiana pratica didattica.  Teaching science in Europe: language issues compared (Italy, Denmark, Wales The linguistic component plays a major role in the teaching and learning of science, specifically prescribed by the curriculum currently in force in Europe and fully supported by the National Guidelines for the curriculum in kindergarten and the first cycle of education, regulated by DM 254/2012. This paper aims to investigate the linguistic-communicative impact in the process of teaching and learning science in three different European contexts: Italy, Denmark and Wales in children aged 11 to 14, corresponding in Italy to Middle school, in Denmark to a segment of the Folkeskole, and in Wales to the initial phase of the Secondary school. The research focused on a

  6. Clean, Logistically Light Access to Explore the Closest Places on Earth to Europa and Enceladus

    Science.gov (United States)

    Winebrenner, D. P.; Elam, W. T.; Kintner, P. M. S.; Tyler, S.; Selker, J. S.

    2016-12-01

    At present, the logistical costs of ice drilling to depths of kilometers severely limit sampling and measurements beneath ice sheets. Thus only a tiny fraction of the 400 known subglacial lakes beneath the Antarctic Ice Sheet can ever be sampled by drilling, and study of large lakes may be limited to observations at one or, at best, a few sites. Antarctic lakes are likely highly diverse in their geochemical and geothermal fluxes, the timing and duration of their glaciations, and other characteristics. They constitute a remarkable collection of natural laboratories for learning biogeochemistries and adaptations of subglacial life on Earth. Moreover, they are arguably Earth-analogs to ice-covered seas on Europa and Enceladus, closer not only in relative terms than other analogs, but also usefully close in absolute terms for learning solar-system-wide features of ice-covered seas. It is therefore essential to sample Antarctic lakes with enough range and density, in space and time, to gain better understanding of their workings than drilling alone can provide. The logistics of thermal melt probes makes them attractive, provided that key limitations can be overcome. In particular, melt probes from the 1960s through the 1990s were unreliable, all halted in their descents by electrical failures at high voltages (which are necessary for efficient power use). Moreover, the hole above a classical melt probe refreezes, so neither samples nor the probe itself can be recovered. Here we report progress in overcoming both of these limitations with modern materials and components for reliable high-voltage operation. We have demonstrated in Greenland a 6.5 cm-diameter melt probe operating at 1050V/2.15 kW (electrical) that descended at 2.4 m/hr to 80 m depth in 2013, and after restarting in 2014, to 400 m depth, where we turned it off. We also operated a probe at 2000V/4.5 kW in 2014, which descended at 6.6 m/hr (according to a validated engineering model). These results are the

  7. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements...

  8. The solar power satellite

    Energy Technology Data Exchange (ETDEWEB)

    Combes, P.F.

    1982-01-01

    The construction, launch, components, and operations of satellite solar power systems (SSPS) for direct beaming of solar energy converted to electricity to earth stations are outlined. The reference designs of either Si or concentrator GaAs solar cell assemblies large enough to project 5 GW of power are described. The beam will be furnished by klystrons or amplitrons for reception by rectennas on earth. Conforming to the law of amplitude and the equiphase law will permit high efficiencies, pointing accuracy, and low power deposition/sq cm, thus avoiding environmental problems, although some telecommunications systems may suffer interference. The construction of the dipole rectenna grid is sketched, noting that one receiver would be an ellipse sized at 10 x 13 km. Various forms of pollution which could result from the construction of an SSPS are examined.

  9. Launching the First Indian Satellite

    Indian Academy of Sciences (India)

    materials and chemicals, rocket propulsion, satellite technology, control and guidance system, etc. ... entire country, especially the rural areas, and in the survey and management of natural resources. Listeners are no .... satellite will store the information over a longer period and then on command from the ground station at ...

  10. Integrated Satellite-HAP Systems

    DEFF Research Database (Denmark)

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo

    2005-01-01

    Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element for an...

  11. Newspaper Uses of Satellite Technology.

    Science.gov (United States)

    Johns, David

    Replacing slower mail service, satellite transmission now gives the newspaper industry a practical and almost spontaneous method for sending all kinds of information to any newspaper across the country. Unlike other communication industries, newspapers did not begin to make widespread use of satellite technology until 1979, when government…

  12. Satellite Demonstration: The Videodisc Technology.

    Science.gov (United States)

    Propp, George; And Others

    1979-01-01

    Originally part of a symposium on educational media for the deaf, the paper describes a satellite demonstration of video disc materials. It is explained that a panel of deaf individuals in Washington, D.C. and another in Nebraska came into direct two-way communication for the first time, and video disc materials were broadcast via the satellite.…

  13. A Primer on Satellite Equipment.

    Science.gov (United States)

    Doan, Michael

    1992-01-01

    Information provided for school districts desiring to offer distance education courses to their students describes the kind of satellite dish needed; its size, sturdiness, placement, and number of dishes needed; satellite receivers; the function of a descrambler; copyright restrictions; features of an Integrated Receiver/Descrambler; selecting a…

  14. The Skeletal Muscle Satellite Cell

    Science.gov (United States)

    2011-01-01

    The skeletal muscle satellite cell was first described and named based on its anatomic location between the myofiber plasma and basement membranes. In 1961, two independent studies by Alexander Mauro and Bernard Katz provided the first electron microscopic descriptions of satellite cells in frog and rat muscles. These cells were soon detected in other vertebrates and acquired candidacy as the source of myogenic cells needed for myofiber growth and repair throughout life. Cultures of isolated myofibers and, subsequently, transplantation of single myofibers demonstrated that satellite cells were myogenic progenitors. More recently, satellite cells were redefined as myogenic stem cells given their ability to self-renew in addition to producing differentiated progeny. Identification of distinctively expressed molecular markers, in particular Pax7, has facilitated detection of satellite cells using light microscopy. Notwithstanding the remarkable progress made since the discovery of satellite cells, researchers have looked for alternative cells with myogenic capacity that can potentially be used for whole body cell-based therapy of skeletal muscle. Yet, new studies show that inducible ablation of satellite cells in adult muscle impairs myofiber regeneration. Thus, on the 50th anniversary since its discovery, the satellite cell’s indispensable role in muscle repair has been reaffirmed. PMID:22147605

  15. Mobility management in satellite networks

    Science.gov (United States)

    Johanson, Gary A.

    1995-01-01

    This paper addresses the methods used or proposed for use in multi-beam and/or multi-satellite networks designed to provide Mobile Satellite Services (MSS). Specific topics include beam crossover in the North American Mobile Satellite (MSAT) system as well as registration and live call hand-off for a multi-regional geosynchronous (GEO) satellite based system and a global coverage Low Earth Orbiting (LEO) system. In the MSAT system, the individual satellite beams cover very large geographic areas so the need for live call hand-off was not anticipated. This paper discusses the methods used to keep track of the beam location of the users so that incoming call announcements or other messages may be directed to them. Proposed new GEO systems with large numbers of beams will provide much smaller geographic coverage in individual beams and thus the need arises to keep track of the user's location as well as to provide live call hand-off as the user traverses from beam to beam. This situation also occurs in proposed LEO systems where the problems are worsened by the need for satellite to satellite hand-off as well as beam to beam hand-off within a single satellite. The paper discusses methods to accomplish these handoffs and proposes system architectures to address the various hand-off scenarios.

  16. Accumulation of satellites

    International Nuclear Information System (INIS)

    Safronov, V.S.; Ruskol, E.L.

    1977-01-01

    Formation and evolution of circumplanetary satellite swarms are investigated. Characteristic times of various processes are estimated. The characteristic time for the accumulation of the bodies in the swarm was several orders of magnitude shorter than that of the planet, i.e. than the time of the replenishment of the material by the swarm (10 8 yr). The model of the accumulation of the swarm is constructed taking into account the increase of its mass due to trapping of heliocentrically moving particles and its decrease due to outfall of the inner part of the swarm onto the growing planet. The accumulation of circumplanetary bodies is also considered. The main features of the evolution of the swarm essentially depend on the size distribution of bodies in the swarm and in the zone of the planet and also on the degree of the concentration of the swarm mass toward the planet. If the sum of the exponents of the inverse power laws of these distributions is less than 7, the model of the transparent swarm developed in this paper should be preferred. When this sum is greater than 7, the model of opaque swarm suggested by A. Harris and W.M. Kaula is better. There is predominant trapping of small particles into the swarm due to their more frequent collisions. Optical thickness of the protoplanetary cloud in radial direction is estimated. It is shown that at the final stage of the planetary accumulation, the cloud was semitransparent in the region of terrestrial planets and volatile substances evaporated at collisions could be swept out from the outer parts of the satellite swarm by the solar wind

  17. Sky alert! when satellites fail

    CERN Document Server

    Johnson, Les

    2013-01-01

    How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at areas where the loss could have catastrophic effects. The book - demonstrates our dependence on space technology and satellites; - outlines the effect on our economy, defense, and daily lives if satellites and orbiting spacecraft were destroyed; - illustrates the danger of dead satellites, spent rocket stages, and space debris colliding with a functioning satellites; - demonstrates the threat of dramatically increased radiation levels associated with geomagnetic storms; - introduces space as a potential area of conflict between nations.

  18. Encryption protection for communication satellites

    Science.gov (United States)

    Sood, D. R.; Hoernig, O. W., Jr.

    In connection with the growing importance of the commercial communication satellite systems and the introduction of new technological developments, users and operators of these systems become increasingly concerned with aspects of security. The user community is concerned with maintaining confidentiality and integrity of the information being transmitted over the satellite links, while the satellite operators are concerned about the safety of their assets in space. In response to these concerns, the commercial satellite operators are now taking steps to protect the communication information and the satellites. Thus, communication information is being protected by end-to-end encryption of the customer communication traffic. Attention is given to the selection of the NBS DES algorithm, the command protection systems, and the communication protection systems.

  19. Polar-Orbiting Satellite (POES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from camera systems or radiometer instruments on satellites in orbit around the poles. Satellite campaigns include...

  20. Attualità e prospettive della “Rete per l’Identità” - Argentina/Sud America/Europa

    Directory of Open Access Journals (Sweden)

    Roberta Murroni

    2010-03-01

    Full Text Available Attualità e prospettive della “Rete per l’Identità” - Argentina/Sud America/Europa
    (13-14 Novembre 2010, Centro di Documentazione Mastinu- Marras Tresnuraghes -OR-
    di Roberta Murroni

  1. Theory of satellite geodesy applications of satellites to geodesy

    CERN Document Server

    Kaula, William M

    2000-01-01

    The main purpose of this classic text is to demonstrate how Newtonian gravitational theory and Euclidean geometry can be used and developed in the earth's environment. The second is to collect and explain some of the mathematical techniques developed for measuring the earth by satellite.Book chapters include discussions of the earth's gravitational field, with special emphasis on spherical harmonies and the potential of the ellipsoid; matrices and orbital geometry; elliptic motion, linear perturbations, resonance, and other aspects of satellite orbit dynamics; the geometry of satellite obser

  2. VLBI Observations of Geostationary Satellites

    Science.gov (United States)

    Artz, T.; Nothnagel, A.; La Porta, L.

    2013-08-01

    For a consistent realization of a Global Geodetic Observing System (GGOS), a proper tie between the individual global reference systems used in the analysis of space-geodetic observations is a prerequisite. For instance, the link between the terrestrial, the celestial and the dynamic reference system of artificial Earth orbiters may be realized by Very Long O Baseline Interferometry (VLBI) observations of one or several satellites. In the preparation phase for a dedicated satellite mission, one option to realize this is using a geostationary (GEO) satellite emitting a radio signal in X-Band and/or S-Band and, thus, imitating a quasar. In this way, the GEO satellite can be observed by VLBI together with nearby quasars and the GEO orbit can, thus, be determined in a celestial reference frame. If the GEO satellite is, e.g., also equipped with a GNSS-type transmitter, a further tie between GNSS and VLBI may be realized. In this paper, a concept for the generation of a radio signal is shown. Furthermore, simulation studies for estimating the GEO position are presented with a GEO satellite included in the VLBI schedule. VLBI group delay observations are then simulated for the quasars as well as for the GEO satellite. The analysis of the simulated observations shows that constant orbit changes are adequately absorbed by estimated orbit parameters. Furthermore, the post-fit residuals are comparable to those from real VLBI sessions.

  3. Security Concepts for Satellite Links

    Science.gov (United States)

    Tobehn, C.; Penné, B.; Rathje, R.; Weigl, A.; Gorecki, Ch.; Michalik, H.

    2008-08-01

    The high costs to develop, launch and maintain a satellite network makes protecting the assets imperative. Attacks may be passive such as eavesdropping on the payload data. More serious threat are active attacks that try to gain control of the satellite, which may lead to the total lost of the satellite asset. To counter these threats, new satellite and ground systems are using cryptographic technologies to provide a range of services: confidentiality, entity & message authentication, and data integrity. Additionally, key management cryptographic services are required to support these services. This paper describes the key points of current satellite control and operations, that are authentication of the access to the satellite TMTC link and encryption of security relevant TM/TC data. For payload data management the key points are multi-user ground station access and high data rates both requiring frequent updates and uploads of keys with the corresponding key management methods. For secure satellite management authentication & key negotiation algorithms as HMAC-RIPEMD160, EC- DSA and EC-DH are used. Encryption of data uses algorithms as IDEA, AES, Triple-DES, or other. A channel coding and encryption unit for payload data provides download data rates up to Nx250 Mbps. The presented concepts are based on our experience and heritage of the security systems for all German MOD satellite projects (SATCOMBw2, SAR-Lupe multi- satellite system and German-French SAR-Lupe-Helios- II systems inter-operability) as well as for further international (KOMPSAT-II Payload data link system) and ESA activities (TMTC security and GMES).

  4. La paradoja eudemonista de la política de los países de Europa del Sur

    Directory of Open Access Journals (Sweden)

    Katerina Fédorova

    2015-01-01

    Full Text Available Las tendencias contemporáneas de la crisis financie- ra y política en los países de Europa del Sur necesitan el análisis complejo para la formación de la estrategia eficaz anticrisis del país. El énfasis se ha puesto en el conflic- to de objetivos del perfeccionismo entre dos vectores de realización –el privado y el nacional–. Se analiza profun- damente el Estado como un organismo político según la teoría orgánica de sociedad, para aclarar los procesos regresivos que se están adelantando en los países del gru- po PIIGS de Europa del Sur. Se presta especial atención al descubrimiento de la paradoja eudemonista, la eluci- dación de lo cual solucionaría los procesos de crisis. Los resultados recibidos son importantes para los países de Europa Meridional, especialmente para los que pertene- cen al grupo PIIGS, y también, los resultados que pueden ser aplicados a cada subjeto de relaciones internacionales. Asimismo, se formulan cinco fases de procesos regresivos del Estado, que ayudarán a evaluar el grado del daño de los procesos destructivos del país. Abstract Contemporary financial and political crisis tenden- cies in the Southern European countries require a com- prehensive analysis to formulate an effective anti-crisis strategy of the country. The emphasis has been placed on a conflict of the perfectionism purposes between two vec- tors of interest –the private and the national–. It is deeply analyzed the state as a political organism, based on the organic theory of society, to clarify the regressive process- es that is developing in the PIIGS group countries of the Southern Europe. The distinctiveness of this article is the discovery of the eudemonistic paradox by the author. The elucidation of the eudaimonistic paradox will solve the problems of the crisis processes. The obtained results are important for the countries of the Southern Europe, es- pecially for the PIIGS countries, and also

  5. Satellite communications principles and applications

    CERN Document Server

    Calcutt, David

    1994-01-01

    Satellites are increasingly used for global communications, as well as for radio and television transmissions. With the growth of mobile communications, and of digital technology, the use of satellite systems is set to expand substantially and already all students of electronics or communications engineering must study the subject.This book steers a middle path between offering a basic understanding of the process of communication by satellite and the methodology used; and the extensive mathematical analysis normally adopted in similar texts. It presents the basic concepts, using as mu

  6. Absence of satellites of asteroids

    International Nuclear Information System (INIS)

    Gehrels, T.; Drummond, J.D.; Levenson, N.A.

    1987-01-01

    The absence of satellites within 0.1-7.0 arcmin of minor planets noted in the present CCD imaging survey is judged consistent with previous theoretical studies of collisions in which it is held that satellites would have to be larger than about 30 km in order to be collisionally stable. In view of tidal stability, the only main belt asteroid satellites which could conceivably possess stability over eons are near-contact binaries. Any recent collisional debris would be chaotic and collisionally unstable. 15 references

  7. Alexander von Humboldt brachte Guano nach Europa - mit ungeahnten globalen Folgen

    Directory of Open Access Journals (Sweden)

    Bärbel Rott

    2016-05-01

    Full Text Available Zusammenfassung Die vorliegende Abhandlung beschäftigt sich mit einem bisher wenig beachteten Aspekt von Humboldts Amerikanischer Reise (1799─1804. Während seine Studien der Pflanzen- und Tierwelt bis heute große Aufmerksamkeit genießen, wird Humboldts Beitrag zu der Entwicklung der modernen Landwirtschaft wenig beachtet. Während seines Aufenthalts in Lima erhielt er Proben von Guano, Vogelmist von den Chincha-Inseln vor der peruanischen Küste. Einige Proben, die er von dieser Reise zurückbrachte, wurden von Wissenschaftlern in Frankreich und Deutschland untersucht. Die Analysenergebnisse zeigten außerordentlich hohe Gehalte an Pflanzennährstoffen, insbesondere Stickstoff und Phosphor. In den folgenden Jahrzehnten wurde Guano zu einem bedeutsamen Düngemittel und Auslöser eines Booms in Europa und Peru. Die Auswirkungen dieser Entwicklung sind bis heute sichtbar und werden hier unter besonderer Beachtung von Phosphor beschrieben. Abstract One aspect of Humboldt’s travel to South America (1799─1804 received little attention. The fascination of his studies of the South American flora and fauna is unbroken to the present day. Yet Humboldt’s contribution to modern agriculture remains almost unnoticed. During his stay in Lima Humboldt received samples of guano, a mixture of bird droppings from the Chincha Islands off the Peruvian coast, which he took to Europe and had analyzed by the most famous chemists in France and Germany. The results showed outstanding fertilizing effects, in particular due to the high content of nitrogen and phosphorus. The ensuing boom starting from the 1840s influenced agriculture in Europe and the economy of Peru seriously. Some aspects of this historical development may give an idea of the ensuing change not only in agriculture. Résumé Il y a un aspect du voyage de Alexander von Humboldt en Amérique du Sud (1799─1804 qui jusqu’à présent a été peu considéré. Ses études de la flore at le da

  8. Integración regional y nacionalismos en la Europa del siglo XXI

    Directory of Open Access Journals (Sweden)

    Doval Adán, Antonio

    2015-06-01

    Full Text Available In the current European geopolitical space live two antagonistic activism. One works for a more united and integrated economic and social political level by creating large supranational structures more complex and bureaucratized with extensive powers, while the other strives to claim a greater degree of sovereignty and independence for the peoples and their territorial identities. In this context, a general hoverriewof international organizations created to promote the regional integration process istakew as well as a discussion onthe main focuses and nationalist movements that operate in the European territory, delving into the resurgence of secessionist movements within the European Union in the Balkans and the former Soviet Union, not least the question of Kurdish nationalism.En el espacio geopolítico europeo actual conviven dos activismos antagónicos. Uno trabaja a favor de una Europa más unida e integrada a nivel político económico y social mediante la creación de grandes estructuras supranacionales cada vez más complejas y burocratizadas dotadas de amplios poderes, mientras que el otro se esfuerza en reivindicar un mayor grado de soberanía e independencia para los pueblos y sus identidades territoriales. En este contexto, se hace un balance general de las organizaciones internacionales creadas para impulsar el proceso de integración regional y se analizan los principales focos y movimientos nacionalistas que operan en el territorio europeo, profundizando en el rebrote de los movimientos secesionistas dentro de la Unión Europea, en los Balcanes y en el espacio postsoviético, sin olvidar la cuestión del nacionalismo kurdo. [fr] Dans la zone géopolitique européenne actuelle vivent deux activismes antagonistes. Un travaille en faveur d’une Europe plus unie et intégré à un niveau politique, économique et social par le biais de la création de grandes structures supranationales plus en plus complexes et bureaucratissées avec

  9. German energy policy in deregulated Europe; Deutsche Energiepolitik im liberalisierten Europa

    Energy Technology Data Exchange (ETDEWEB)

    Kuhnt, D. [RWE Energie AG, Essen (Germany)

    2000-07-01

    regulations on protection of cogeneration, and the rising payments for electricity from renewable sources fed into the public power grid total approx. DM 11 billion in the current year. This offsets a large part of the DM 15-20 billion savings arising to electricity consumers as a result of competition. (orig.) [German] Der Autor fordert eine Versachlichung der deutschen Energiepolitik und formuliert dazu einige Thesen: Erstens muss die deutsche Energiepolitik den neuen marktwirtschaftlichen Ordnungsrahmen in Europa akzeptieren. Das bedeutet, dass die deutschen Unternehmen nicht weiter mit der Verwirklichung politischer Zielvorstellungen belastet werden. Die deutsche Energiewirtschaft braucht Chancengleichheit mit den europaeischen Mitbewerbern. So sollten sich auch die europaeischen Partnerlaender nicht auf die Mindestbedingungen der Binnenmarkt-Richtlinie zur Marktoeffnung beschraenken. Zweitens muss die deutsche Energiepolitik im Interesse von inlaendischer Beschaeftigung und Wertschoepfung angesichts des erheblich gewachsenen Wettbwerbsdrucks neue Formen der Kooperation mit der Energiewirtschaft entwickeln. Auch die Zielkonflikte zwischen Nachhaltigkeit, Versorgungssicherheit und Wirtschaftlichkeit muessen nicht nur moderiert, sondern produktiv aufgeloest werden. Drittens bedeutet dies: Keine unzumutbare Loesung in Sachen Kernenergie. Wer die deutsche Energiewirtschaft im Interesse der heimischen Arbeitsplaetze und Zukunftschancen in ihrer Staerke erhalten will, kann nicht in Kauf nehmen, dass die deutsche Energiewirtschaft zusaetzliche Marktanteile im Inland an andere europaeische Unternehmen verliert. Viertens brauchen wir eine neue Energiepolitik, die rational und weniger emotional die Ergebnisse des Marktes zur Kenntnis nimmt. Sie sollte sich in diesem Zusammenhang kuenftig auf die marktgerechte Foerderung von erneuerbaren Energien und Technologien zur Steigerung der Energieeffizienz beschraenken. Fuenftens darf die deutsche Energiepolitik jetzt nicht den Fehler

  10. ESCENARIOS DE LA MIGRACIÓN LATINOAMERICANA: LA VIDA FAMILIAR TRANSNACIONAL ENTRE EUROPA Y AMÉRICA LATINA

    Directory of Open Access Journals (Sweden)

    Isabel Yepez del Castillo

    2014-01-01

    Full Text Available Este artículo tiene tres partes, en la primera pasamos revista a las migraciones entre Europa y América Latina desde una perspectiva de larga duración destacando las incidencias de la globalización en el aumento de las desigualdades entre países y en los procesos de movilidad social ascendente y descendente de las familias migrantes. En la segunda, abordamos los escenarios posibles y estrategias múltiples de la presencia latinoamericana en la Unión Europea en el contexto de crisis global. Finalmente, nos interrogamos sobre la incidencia que las actuales políticas migratorias, de gestión de la crisis y del mercado de trabajo, tienen sobre la vida familiar de los diferentes colectivos latinoamericanos.

  11. Escenarios de la migración latinoamericana: la vida familiar transnacional entre Europa y América Latina

    Directory of Open Access Journals (Sweden)

    Isabel Yepez del Castillo

    2014-09-01

    Full Text Available Este artículo tiene tres partes, en la primera pasamos revista a las migraciones entre Europa y América Latina desde una perspectiva de larga duración destacando las incidencias de la globalización en el aumento de las desigualdades entre países y en los procesos de movilidad social ascendente y descendente de las familias migrantes. En la segunda, abordamos los escenarios posibles y estrategias múltiples de la presencia latinoamericana en la Unión Europea en el contexto de crisis global. Finalmente, nos interrogamos sobre la incidencia que las actuales políticas migratorias, de gestión de la crisis y del mercado de trabajo, tienen sobre la vida familiar de los diferentes colectivos latinoamericanos.

  12. Transformaciones sociales en el Neolítico final de la Europa templada (4000-2000 a.C.

    Directory of Open Access Journals (Sweden)

    Kristiansen, Kristian

    1989-12-01

    Full Text Available Changes in the archaeological record of temperate Europe from the TRB/ Megalithic to the Corded/Ware/Battle / Axe/Single Grave cultural complexes are examined in terms of transformations in subsistence patterns (slash-and-burn farming vs. pastoralísm, surplus distribution (feasting vs. wealth exchange, and ritual practices (collective vs. individualizing.

    Se examinan los cambios en el registro arqueológico de la Europa templada desde los complejos culturales TRB/Megalítico al de la Cerámica cordada/Hacha de Combate/ Tumba individual atendiendo a las transformaciones en los patrones de subsistencia (agricultura de rozas vs. pastoreo, distribución del excedente (festejos (2 vs. intercambio de riqueza y prácticas rituales (colectivas vs. individualizadoras.

  13. Gas prices in Europe before oligopoly and liberalization; Il prezzo del gas in Europa tra liberalizzazione e oligopolio

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, A.

    1998-09-01

    The forthcoming incorporation of the EU Directive on the internal gas market shall set the conditions to increase competition among suppliers, thus lowering gas prices in Europe. But, in perspective, the strategic decisions taken by the majors tend to a stronger oligopoly coordination to sustain prices and share the gas price premium provided by environmental constraints and the technical dominance of combined-cycle plants. [Italiano] Con la direttiva comunitaria sul mercato interno del gas si dovrebbero creare le condizioni per una maggiore competizione tra i fornitori e, quindi, per una riduzione dei prezzi del gas in Europa. Le azioni strategiche delle major paiono invece tendere, in prospettiva, a un piu` forte coordinamento oligopolistico per sostenere i prezzi e spartirsi l`incremento di premio del gas garantito dai vincoli ambientali e dal dominio del ciclo combinato.

  14. Ampliando la protección a segundas indicaciones en Europa: swiss-type claim y european-type claim

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Conde-Gutiérrez

    2015-06-01

    Full Text Available La Oficina de Patentes Europea (EPO protege las segundas indicaciones o usos sobre composiciones o sustancias ya existentes en el estado de la técnica con el ánimo de incentivar a la industria farmacéutica en Europa. Este artículo explora los aspectos legales y técnicos mediante los cuales la EPO ha otorgado patentes no solo a segundas indicaciones, sino también a terceras o sucesivas indicaciones. En particular, se analiza el alcance del Swiss-type Claim y el European-type Claim. De igual manera, se realiza un análisis comparativo entre el Convenio sobre Patentes Europeo y decisiones de la EPO, y la Decisión 486 de 2000 de la Comunidad Andina (Régimen Común sobre Propiedad Industrial sobre segundas indicaciones.

  15. ¿Importa Europa en las elecciones europeas? Un modelo explicativo de las elecciones del 2009 al Parlamento Europeo

    Directory of Open Access Journals (Sweden)

    Paolo Bellucci

    2012-01-01

    Full Text Available Este trabajo evalúa la validez de diferentes modelos interpretativos del comportamiento electoral en las elecciones europeas partiendo del resultado de junio de 2009. Nos centramos, en primer lugar, en modelos que conectan el voto europeo con aspectos políticos basados en el nivel nacional (modelo de segundo orden y en el ciclo electoral doméstico (modelo de ciclo electoral; en segundo lugar se evalúa la capacidad explicativa de un modelo reñido con las interpretaciones tradicionales, y basado en el papel de la posición de los partidos políticos y la campaña electoral (modelo de Europa importa. Finalmente, se avanza un modelo sintético, con el objetivo de proporcionar una más sólida explicación de las elecciones de 2009 al Parlamento Europeo.

  16. Contratación Pública electrónica en Europa y América Latina

    Directory of Open Access Journals (Sweden)

    Carlos Delpiazzo

    2011-12-01

    Full Text Available La convergencia tecnológica (de la Informática y las Telecomunicaciones y la convergencia jurídica (de los Derechos administrativos impuesta por la globalización han aparejado sensibles transformaciones en el campo de la contratación pública. Partiendo de la consideranción de los acuerdos alcanzados en materia a nivel de la Organización Mundial del Comercio (OMC, de la Unión Europea (UE y del Mercado Común del Sur (MERCOSUR, el trabajo examina cómo se ha evolucionado hacia la regulación de la contratación pública por medios electrónicos en Europa y América Latina.

  17. Statistical-dynamic climate forecast for Europe and Germany. Final report; Statistisch-dynamische Klimavorhersage fuer Europa und Deutschland. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Denhard, M.; Schoenwiese, C.D.

    2001-07-01

    Principal Correlation Pattern Analysis (PCPA) maps the local circulation, temperature and precipitation anomalies in the northern hemisphere in monthly resolution and permits an interpretation of their causes. Calculations are made for the El Nino phenomenon, NAO, and the quasi-11-year cycle of solar radiation variation. Especially the El Nino calculations show the efficiency of PCPA. [German] Mit Hilfe der Principal Correlation Pattern Analysis (PCPA) koennen die von verschiedenen Klimaantrieben erzeugten lokalen Zirkulations-, Temperatur- und Niederschlagsanomalien auf der Nordhemisphaere in monatlicher Aufloesung dargestellt und ursaechlich interpretiert werden. Diese Rechnungen wurden fuer das El Nino Phaenomen, die NAO und den quasi 11-jaehrigen Zyklus der solaren Strahlungsschwankungen durchgefuehrt. Insbesondere die Untersuchungen zu Wirkungen von El Nino auf Europa zeigen, dass die PCPA die Kopplungen eines Prozesses mit dem Klimasystem sehr genau beschreibt und somit die Voraussetzungen schafft, die Wirkungen dieses Klimaantriebs zu modellieren und ihn zur Vorhersage zu nutzen. Erste einfache Vorhersageexperimente fuer das europaeische Klima bestaetigen diese Aussage. (orig.)

  18. Fatal toxic leukoencephalopathy secondary to overdose of a new psychoactive designer drug 2C-E ("Europa").

    Science.gov (United States)

    Sacks, Justin; Ray, M Jordan; Williams, Sue; Opatowsky, Michael J

    2012-10-01

    We present a case of a fatal toxic leukoencephalopathy following ingestion of a new psychoactive designer drug known as 2C-E or "Europa." Recreational drugs, particularly hallucinogenic substances, appear to be growing in popularity, with increasing amounts of information available via the Internet to entice potential users. In addition, some newer "designer" psychoactive substances are available for purchase online without adverse legal consequences, therefore adding to their popularity. We describe magnetic resonance imaging (MRI) findings to include selective diffuse toxic injury of the cerebral white matter with sparing of the cortex and most of the deep gray nuclei. To our knowledge, this is the first reported description of cerebral findings on MRI that are likely related to a lethal ingestion of 2C-E.

  19. Satellite tracking of threatened species

    Science.gov (United States)

    Williams, M.; Lunsford, A.; Ellis, D.; Robinson, J.; Coronado, P.; Campbell, W.

    1998-01-01

    In 1990, a joint effort of two U.S. federal agencies, NASA Goddard Space Flight Center (GSFC) and the Patuxent Wildlife Research Center, began. We initially joined forces in a project that used satellite telemetry to discover the winter home of a tiny dwindling population of Siberian Cranes. Since then several projects have emerged, and a web site was created to follow some of these activities. This web site is called the Satellite Tracking of Threatened Species and its location is http://sdcd.gsfc.nasa.gov/ISTO/satellite_tracking. It describes the overall program, and links you to three subsections that describe the projects in more detail: Satellite Direct Readout, Birdtracks, and Birdworld.

  20. Commercial satellite broadcasting for Europe

    Science.gov (United States)

    Forrest, J. R.

    1988-12-01

    A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future.

  1. Small Satellite Mechanical Design Experience

    OpenAIRE

    Meyers, Stewart

    1993-01-01

    The design approach used and the experience gained in the building of four small satellite payloads is explained. Specific recommendations are made and the lessons learned on the SAMPEX program are detailed.

  2. Sea Turtle Satellite Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles captured in various fishing gear (pound nets, long haul seines, gill nets) were outfitted with satellite transmitters so that their movements, migratory...

  3. Next generation satellite communications networks

    Science.gov (United States)

    Garland, P. J.; Osborne, F. J.; Streibl, I.

    The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

  4. Satellite Teleconferencing in the Caribbean.

    Science.gov (United States)

    Sankar, Hollis C.

    1985-01-01

    Discusses the need for, and the development, use, and future trends of, the University of the West Indies Distance Teaching Experiment, which utilizes telephone and communications satellite technology teleconferencing to extend educational opportunities to the peoples of the Caribbean. (MBR)

  5. The Educational Satellite in Perspective

    Science.gov (United States)

    Fraser, D. O.

    1975-01-01

    A discussion which contends that there is merit in not gearing satellite systems solely to educational broadcasting and that they should be designed for general communication, including telephony and television entertainment. (Author/HB)

  6. Descent Without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds

    Science.gov (United States)

    Loeffler, Mark Josiah; Hudson, Reggie Lester

    2015-01-01

    The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NHþ 4 and SO2 making SO2 4 by H+ and e - transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.

  7. Europa y el pensamiento político del Imperio. Hacia una crítica del modernismo imperial.

    Directory of Open Access Journals (Sweden)

    Peter Wagner

    2005-03-01

    Full Text Available Este ensayo sugiere que cierta forma de pensamiento ha alcanzado una posición central en la filosofía política contemporánea —una combinación de liberalismo individualista y racionalismo instrumental—. Aeste pensamiento lo denomino modernismo imperial porque se basa en una interpretación concreta del compromiso moderno con la autonomía, sesgado hacia la hegemonía. Desde ese planteamiento se procura mostrar que ésta no es la única interpretación sostenible de la modernidad y que puede estar surgiendo una auto-comprensión normativa concreta de la modernidad europea que se diferencie del modernismo imperial. El texto intenta elucidar esta tesis en dos pasos. Primero, ofrece una comparación algo esquemática del pensamiento social y político en Europa y EE.UU., muestra los rasgos básicos del modernismo imperial e indica algunas razones —históricas y contingentes— de su predominio en EE.UU., pese a que sus fuentes estén en Europa. Dado que este paso muestra que el individualismo y el instrumentalismo son los rasgos clave del modernismo imperial, el segundo paso discutirá las consecuencias de una posible futura hegemonía de ese pensamiento explorando en particular cómo la cuestión de lo común se ha vuelto problemática en la filosofía política desde el ascenso del liberalismo individualista.

  8. La religión como currículo social: educación, valores e Islam en Europa

    Directory of Open Access Journals (Sweden)

    Vicente Javier Llorent García

    2013-12-01

    Full Text Available Cuando la religión se convierte en parte integrante de los debates políticos modernos, las ideas religiosas influyen en las decisiones y definiciones de conceptos como la educación, la participación en el mercado laboral, la estructura y función de la familia como unidad social y la igualdad. La integración y la inmigración pasan a primer plano a medida que el concepto de ciudadanía adquiere dimensiones culturalistas y moralizantes. Finalmente, religión, política y educación se interfieren en las áreas de la vida que pertenecen a la esfera privada y pública. Desde nuestra perspectiva pedagógica, entendemos que las líneas educativas marcadas por la religión influyen notablemente en el devenir de muchos ciudadanos y se incrustan en el foro político-social. Así nos encontramos que la religión como poderoso instrumento de socialización ejerce una gran influencia intencionada en la educación y valores de los ciudadanos y se configura como el currículo social, normalmente oculto, del contexto próximo de muchos ciudadanos. La presencia del Islam y los musulmanes en Europa, aunque no es un fenómeno nuevo, es cuestionada por los Estados-nación confrontando el currículo oficial, la educación reglada, con el currículo social, muy influido por el Islam entre sus fieles. De esta manera se convierte en parte integrante de la lucha por la identidad nacional individual y colectiva, ya sea en lo referente al laicismo, la democracia o ciudadanía. Y en este sentido, queremos aportar una revisión actualizada de esta cuestión tan presente en Europa.

  9. Existence of undiscovered Uranian satellites

    International Nuclear Information System (INIS)

    Boice, D.C.

    1986-04-01

    Structure in the Uranian ring system as observed in recent occultations may contain indirect evidence for the existence of undiscovered satellites. Using the Alfven and Arrhenius (1975, 1976) scenario for the formation of planetary systems, the orbital radii of up to nine hypothetical satellites interior to Miranda are computed. These calculations should provide interesting comparisons when the results from the Voyager 2 encounter with Uranus are made public. 15 refs., 1 fig., 1 tab

  10. Satellite medical centers project

    Science.gov (United States)

    Aggarwal, Arvind

    2002-08-01

    World class health care for common man at low affordable cost: anywhere, anytime The project envisages to set up a national network of satellite Medical centers. Each SMC would be manned by doctors, nurses and technicians, six doctors, six nurses, six technicians would be required to provide 24 hour cover, each SMC would operate 24 hours x 7 days. It would be equipped with the Digital telemedicine devices for capturing clinical patient information and investigations in the form of voice, images and data and create an audiovisual text file - a virtual Digital patient. Through the broad band connectivity the virtual patient can be sent to the central hub, manned by specialists, specialists from several specialists sitting together can view the virtual patient and provide a specialized opinion, they can see the virtual patient, see the examination on line through video conference or even PCs, talk to the patient and the doctor at the SMC and controlle capturing of information during examination and investigations of the patient at the SMC - thus creating a virtual Digital consultant at the SMC. Central hub shall be connected to the doctors and consultants in remote locations or tertiary care hospitals any where in the world, thus creating a virtual hub the hierarchical system shall provide upgradation of knowledge to thedoctors in central hub and smc and thus continued medical education and benefit the patient thru the world class treatment in the smc located at his door step. SMC shall be set up by franchisee who shall get safe business opportunity with high returns, patients shall get Low cost user friendly worldclass health care anywhere anytime, Doctors can get better meaningful selfemplyment with better earnings, flexibility of working time and place. SMC shall provide a wide variety of services from primary care to world class Global consultation for difficult patients.

  11. Spanish Earth Observation Satellite System

    Science.gov (United States)

    Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.

    2010-12-01

    The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

  12. Satellites You Can See for Homework

    Science.gov (United States)

    Broderick, Stephen

    2012-01-01

    Artificial satellites are easily observed most nights when the weather is fine. The website called "Heavens Above" at www.heavens-above.com will help locate these satellites flying over one's location. It also includes how bright they will appear. The direction of travel of each satellite in the night sky also indicates the type of satellite. For…

  13. Shadow imaging of geosynchronous satellites

    Science.gov (United States)

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite

  14. La escritura humanística en la Europa del Renacimiento

    Directory of Open Access Journals (Sweden)

    Juan Carlos Galende Díaz

    1998-01-01

    Full Text Available Uno de los méritos más relevantes de la «escritura humanística» es el haberse impuesto en Europa como escritura virtualmente única y, posteriormente, haberse extendido por el resto de los continentes, siendo en América escritura sin rival —dato de sumo interés desde el punto de vista gráfico y cultural—. Pero existen otros motivos que justifican su estudio, como son: a el hecho de que dicha letra sea la base y origen de la escritura contemporánea, tanto manuscrita como impresa; b su importancia gráfico-cultural para entender el Renacimiento; c con relación al proceso gráfico y evolución de la escritura latina, la letra renacentista constituye el retorno a las formas antiguas de los modelos carolinos; d su introducción coincide con importantes cambios ideológicos y socio-culturales; y e su difusión y promoción inicial depende más de la voluntaria decisión de un restringido número de centros y fiambres cultos: los humanistas y los profesionales, V. gr. escribanos, notarios, profesores, etc. —cuyos nombres nos son histórica y documentalmente conocidos— que de la masa popular. La estructuración del presente artículo es sencilla y pretende ser clara, con los siguientes apartados: 1 breve introducción exponiendo las peculiaridades de carácter general relativas a la letra humanística; 2 panorámica histórico-cultural del período renacentista; 3 nombres con que se ha designado a esta letra; 4 origen y desarrollo de esta escritura con indicación de sus principales promotores, escuelas y círculos de intelectuales; 5 etapas básicas de su evolución; y 6 tipos de letra humanística y características de cada uno de ellos. Por último, además de una bibliografía básica, dividiéndola por temas, en orden a ilustrar los distintos aspectos tratados, se presentan una serie de reproducciones gráficas con textos en letra humanística.One of the most relevant merits of the «humanistic writing» is the fact that it was

  15. Choosing ESRO's first scientific satellites

    Science.gov (United States)

    Russo, Arturo

    1992-11-01

    The choice of the scientific payloads of the European Space Research Organization's (ESRO's) first generation of satellites is analyzed. Concentration is on those aspects of the decision process that involved more directly the scientific community and that emerged as major issues in the discussion of the Launching Program Advisory Committee (LPAC). The main theme was the growing competition between the various fields of space science within the progressive retrenching of the Organization's financial resources available for the satellite program. A general overview of the status of the program by the end of 1966 is presented. The choice of the first small satellites' payloads (ESRO 1 and 2, and HEOS-A) and the difficult definition of the TD satellite program are discussed. This part covers a time span going from early 1963 to the spring of 1966. In the second part, the narrative starts from the spring of 1967, when the decision to recommend a second HEOS-type satellite was taken, and then analyzes the complex situation determined by the crisis of the TD program in 1968, and the debates which eventually led to the abandonment of TD-2 and the start of the far less ambitious ESRO 5 project.

  16. Physical characteristics of satellite surfaces

    International Nuclear Information System (INIS)

    Veverka, J.; Thomas, P.; Johnson, T.V.; Matson, D.; Housen, K.

    1986-01-01

    Both exogenic and endogenic effects have been proposed to explain the major observed characteristics of satellite surfaces. The current view is that the basic properties of most surfaces result from the intrinsic composition of a body and its geologic history. Exogenic effects have, however, played a role in modifying the appearance of nearly all surfaces. The most important exogenic effect is impact cratering, one manifestation of which is the production of micrometeoroid gardened regoliths on airless bodies. On large, silicate bodies the micrometeoroid bombardment can produce an optically mature, dark agglutinate-rich soil; the nature of regoliths on predominantly icy satellites remains uncertain. Direct accumulation of infalling material does not appear to play a major role in modifying most surfaces. Solar wind radiation effects have not altered greatly the optical properties of solar system objects; magnetospheric charged particles may have modified the optical properties of some outer planet satellites (e.g., sulfur ion bombardment in the case of some of the satellites of Jupiter). Other effects, such as aeolian and liquid/solid chemical weathering, may be important on satellites with atmospheres like Titan and Triton

  17. Chartering Launchers for Small Satellites

    Science.gov (United States)

    Hernandez, Daniel

    The question of how to launch small satellites has been solved over the years by the larger launchers offering small satellites the possibility of piggy-backing. Specific fixtures have been developed and commercialized: Arianespace developed the ASAP interface, the USAF studied ESPA, NASA has promoted Shuttle launch possibilities, Russian authorities and companies have been able to find solutions with many different launchers... It is fair to say that most launcher suppliers have worked hard and finally often been able to find solutions to launch most small satellites into orbit. It is also true, however, that most of these small satellites were technology demonstration missions capable of accepting a wide range of orbit and launch characteristics: orbit altitude and inclination, launch date, etc. In some cases the small satellite missions required a well-defined type of orbit and have therefore been obliged to hire a small launcher on which they were the prime passenger. In our paper we would like to propose an additional solution to all these possibilities: launchers could plan well in advance (for example about 3 years), trips to precisely defined orbits to allow potential passengers to organize themselves and be ready on the D-Day. On the scheduled date the chartered launcher goes to the stated orbit while on another date, another chartered launcher goes to another orbit. The idea is to organize departures for space like trains or airplanes leaving on known schedules for known destinations.

  18. Satellite Cell Self-Renewal.

    Science.gov (United States)

    Giordani, Lorenzo; Parisi, Alice; Le Grand, Fabien

    2018-01-01

    Adult skeletal muscle is endowed with regenerative potential through partially recapitulating the embryonic developmental program. Upon acute injury or in pathological conditions, quiescent muscle-resident stem cells, called satellite cells, become activated and give rise to myogenic progenitors that massively proliferate, differentiate, and fuse to form new myofibers and restore tissue functionality. In addition, a proportion of activated cells returns back to quiescence and replenish the pool of satellite cells in order to maintain the ability of skeletal muscle tissue to repair. Self-renewal is the process by which stem cells divide to make more stem cells to maintain the stem cell population throughout life. This process is controlled by cell-intrinsic transcription factors regulated by cell-extrinsic signals from the niche and the microenvironment. This chapter provides an overview about the general aspects of satellite cell biology and focuses on the cellular and molecular aspects of satellite cell self-renewal. To date, we are still far from understanding how a very small proportion of the satellite cell progeny maintain their stem cell identity when most of their siblings progress through the myogenic program to construct myofibers. © 2018 Elsevier Inc. All rights reserved.

  19. Satellite DNA: An Evolving Topic.

    Science.gov (United States)

    Garrido-Ramos, Manuel A

    2017-09-18

    Satellite DNA represents one of the most fascinating parts of the repetitive fraction of the eukaryotic genome. Since the discovery of highly repetitive tandem DNA in the 1960s, a lot of literature has extensively covered various topics related to the structure, organization, function, and evolution of such sequences. Today, with the advent of genomic tools, the study of satellite DNA has regained a great interest. Thus, Next-Generation Sequencing (NGS), together with high-throughput in silico analysis of the information contained in NGS reads, has revolutionized the analysis of the repetitive fraction of the eukaryotic genomes. The whole of the historical and current approaches to the topic gives us a broad view of the function and evolution of satellite DNA and its role in chromosomal evolution. Currently, we have extensive information on the molecular, chromosomal, biological, and population factors that affect the evolutionary fate of satellite DNA, knowledge that gives rise to a series of hypotheses that get on well with each other about the origin, spreading, and evolution of satellite DNA. In this paper, I review these hypotheses from a methodological, conceptual, and historical perspective and frame them in the context of chromosomal organization and evolution.

  20. Space Solar Power: Satellite Concepts

    Science.gov (United States)

    Little, Frank E.

    1999-01-01

    Space Solar Power (SSP) applies broadly to the use of solar power for space related applications. The thrust of the NASA SSP initiative is to develop concepts and demonstrate technology for applying space solar power to NASA missions. Providing power from satellites in space via wireless transmission to a receiving station either on earth, another celestial body or a second satellite is one goal of the SSP initiative. The sandwich design is a satellite design in which the microwave transmitting array is the front face of a thin disk and the back of the disk is populated with solar cells, with the microwave electronics in between. The transmitter remains aimed at the earth in geostationary orbit while a system of mirrors directs sunlight to the photovoltaic cells, regardless of the satellite's orientation to the sun. The primary advantage of the sandwich design is it eliminates the need for a massive and complex electric power management and distribution system for the satellite. However, it requires a complex system for focusing sunlight onto the photovoltaic cells. In addition, positioning the photovoltaic array directly behind the transmitting array power conversion electronics will create a thermal management challenge. This project focused on developing designs and finding emerging technology to meet the challenges of solar tracking, a concentrating mirror system including materials and coatings, improved photovoltaic materials and thermal management.

  1. O Significado da Segurança na Europa: A UE – da PESC ao Colapso da Política Externa

    OpenAIRE

    Charillon, Frédéric

    2001-01-01

    O presente artigo tem por objectivo analisar o significado da segurança na Europa. A construção do processo comunitário dada a especificidade e conteúdo ambicioso do projecto envolvente, leva o autor a passar em revista vários dossiers comunitários de onde resultam consequências sobre o conceito e práticas da segurança europeia. A reinvenção do conceito de segurança na Europa passa em muito pela inserção de novas matérias no tradicional domínio da segurança entre as quais se contam e...

  2. Aus der Forschungspraxis: Journalism in a Global Context – Perspektiven für Afrika und Herausforderungen für Europa

    Directory of Open Access Journals (Sweden)

    Susanne Fengler

    2016-08-01

    Full Text Available In der gegenwärtigen Flüchtlingskrise zeigt sich auf eklatante Weise das Informationsdefizit, das die gegenseitige mediale Wahrnehmung der europäischen und afrikanischen Länder bestimmt. Während in Deutschland und Europa Fluchtursachen und -motive zumeist junger afrikanischer Migranten falsch eingeschätzt und innerkontinentale Migrationsprozesse in Afrika nur marginal in europäischen Medien thematisiert werden, nehmen auch viele Menschen in afrikanischen Ländern nur Ausschnitte aus der Realität des Lebens in Deutschland bzw. Europa wahr. Hieran hat auch die mangelnde Medienberichterstattung in afrikanischen Ländern über Hintergründe und Folgen der Flüchtlingsbewegungen erheblichen Anteil. Der Werkstattbericht bietet auf Grundlage von zwei deutsch-afrikanischen Konferenzen, Literatursichtung und eigenen Studien eine Einschätzung der Berichterstattung auf beiden Kontinenten.

  3. Gaussian entanglement distribution via satellite

    Science.gov (United States)

    Hosseinidehaj, Nedasadat; Malaney, Robert

    2015-02-01

    In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

  4. Advanced satellite servicing facility studies

    Science.gov (United States)

    Qualls, Garry D.; Ferebee, Melvin J., Jr.

    1988-01-01

    A NASA-sponsored systems analysis designed to identify and recommend advanced subsystems and technologies specifically for a manned Sun-synchronous platform for satellite management is discussed. An overview of system design, manned and unmanned servicing facilities, and representative mission scenarios are given. Mission areas discussed include facility based satellite assembly, checkout, deployment, refueling, repair, and systems upgrade. The ferrying of materials and consumables to and from manufacturing platforms, deorbit, removal, repositioning, or salvage of satellites and debris, and crew rescue of any other manned vehicles are also examined. Impacted subsytems discussed include guidance navigation and control, propulsion, data management, power, thermal control, structures, life support, and radiation management. In addition, technology issues which would have significant impacts on the system design are discussed.

  5. Small satellites and their regulation

    CERN Document Server

    Jakhu, Ram S

    2014-01-01

    Since the launch of UoSat-1 of the University of Surrey (United Kingdom) in 1981, small satellites proved regularly to be useful, beneficial, and cost-effective tools. Typical tasks cover education and workforce development, technology demonstration, verification and validation, scientific and engineering research as well as commercial applications. Today the launch masses range over almost three orders of magnitude starting at less than a kilogram up to a few hundred kilograms, with budgets of less than US$ 100.00 and up to millions within very short timeframes of sometimes less than two years. Therefore each category of small satellites provides specific challenges in design, development and operations. Small satellites offer great potentials to gain responsive, low-cost access to space within a short timeframe for institutions, companies, regions and countries beyond the traditional big players in the space arena. For these reasons (particularly the low cost of construction, launch and operation), small (m...

  6. Satellite Communications Using Commercial Protocols

    Science.gov (United States)

    Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan

    2000-01-01

    NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

  7. Leucocytes, cytokines and satellite cells

    DEFF Research Database (Denmark)

    Paulsen, Gøran; Mikkelsen, Ulla Ramer; Raastad, Truls

    2012-01-01

    uncertain. The COX enzymes regulate satellite cell activity, as demonstrated in animal models; however the roles of the COX enzymes in human skeletal muscle need further investigation. We suggest using the term 'muscle damage' with care. Comparisons between studies and individuals must consider changes......-damaging exercise', primarily eccentric exercise. We review the evidence for the notion that the degree of muscle damage is related to the magnitude of the cytokine response. In the third and final section, we look at the satellite cell response to a single bout of eccentric exercise, as well as the role...... variation in individual responses to a given exercise should, however be expected. The link between cytokine and satellite cell responses and exercise-induced muscle damage is not so clear The systemic cytokine response may be linked more closely to the metabolic demands of exercise rather than muscle...

  8. Landsat—Earth observation satellites

    Science.gov (United States)

    ,

    2015-11-25

    Since 1972, Landsat satellites have continuously acquired space-based images of the Earth’s land surface, providing data that serve as valuable resources for land use/land change research. The data are useful to a number of applications including forestry, agriculture, geology, regional planning, and education. Landsat is a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). NASA develops remote sensing instruments and the spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and data distribution. The result of this program is an unprecedented continuing record of natural and human-induced changes on the global landscape.

  9. Resonant satellite transitions in argon

    International Nuclear Information System (INIS)

    Samson, J.A.R.; Lee Eunmee; Chung, Y.

    1990-01-01

    The production of specific Ar + satellite states has been studied with synchrotron radiation at wavelengths between 300 and 350 A with an effective energy resolution of 20 meV. The specific states studied were the ( 3 P)4p( 2 P 3/2 ), ( 1 D)4p( 2 F 7/2 ), and ( 1 D)4p( 2 P 1/2 ) states. The fluorescent radiation emitted from these excited ionic states was measured at 4766, 4611, and 4133 A by the use of narrow band interference filters. The variation of the fluorescence intensity was measured as a function of wavelength. This provided a measure of the relative cross section for production of the satellite states. Each satellite state was found to be completely dominated by autoionization of the neutral doubly excited states (3s 2 3p 4 )nl, n'l' found in this spectral region. (orig.)

  10. La explotación sexual y las políticas de lucha contra la trata de seres humanos en España y Europa

    OpenAIRE

    López Villanueva, Enrique; Jornada sobre el tràfic d'éssers humans com a fenomen transnacional (2016:Mollet del Vallès)

    2016-01-01

    La trata de seres humanos, históricamente hablando, está vinculada a la esclavitud, al comercio esclavista y al tráfico ilegal de personas. La esclavitud es tan antigua como lo son las primeras civilizaciones, de hecho se conocen documentos históricos que datan de la antigua Mesopotamia. Esta ponencia explica el marco legal existente a Europa y España.

  11. Prioridades y desafíos en la cooperación ambiental entre Europa y América Latina: entre gobernanza global y sustentabilidad local

    Directory of Open Access Journals (Sweden)

    Imme Scholz

    2014-06-01

    Full Text Available La cooperación para el desarrollo está pasando por un proceso de redefinición de prioridades debido a los avances de la globalización económica, el cambio climático y los nuevos problemas de seguridad internacional. Este nuevo contexto no deja de influir las relaciones de cooperación entre Europa y América Latina.

  12. Fathoms Below: Propagation of Deep Water-driven Fractures and Implications for Surface Expression and Temporally-varying Activity at Europa

    Science.gov (United States)

    Walker, C. C.; Craft, K.; Schmidt, B. E.

    2015-12-01

    The fracture and failure of Europa's icy shell are not only observable scars of variable stress and activity throughout its evolution, they also serve key as mechanisms in the interaction of surface and subsurface material, and thus crucial aspects of the study of crustal overturn and ice shell habitability. Galileo images, our best and only reasonable-resolution views of Europa until the Europa Multiple Flyby Mission arrives in the coming decades, illustrates a single snapshot in time in Europa's history from which we deduce many temporally-based hypotheses. One of those hypotheses, which we investigate here, is that sub-surface water-both in the form of Great Lake-sized perched water pockets in the near-surface and the larger global ocean below-drives the deformation, fracture, and failure of the surface. Using Galileo's snapshot in time, we use a 2D/3D hydraulic fracturing model to investigate the propagation of vertical fractures upward into the ice shell, motion of water within and between fractures, and the subsequent break-up of ice over shallow water, forming the chaos regions and other smaller surface features. We will present results from a cohesive fragmentation model to determine the time over which chaos formation occurs, and use a fracking model to determine the time interval required to allow water to escape from basal fractures in the ice shell. In determining the style, energy, and timescale of these processes, we constrain temporal variability in observable activity and topography at the surface. Finally, we compare these results to similar settings on Earth-Antarctica-where we have much higher resolution imagery and observations to better understand how sub-surface water can affect ice surface morphology, which most certainly have implications for future flyby and surface lander exploration.

  13. Europa y calidad docente ¿convergencia o reforma educativa? presentación del «XI Congreso de Formación del Profesorado

    Directory of Open Access Journals (Sweden)

    José Emilio Palomero Pescador

    2004-01-01

    Full Text Available En este artículo se hace una breve presentación del «XI congreso de Formación del Profesorado: Europa y calidad docente ¿Convergencia o reforma educativa? » Con él se pretende aproximar al lector, desde una perspectiva crítica, a los principales temas de debate en torno al Espacio Europeo de Educación Superior.

  14. Satellite communications: possibilities and problems

    International Nuclear Information System (INIS)

    Hine, M.

    1986-01-01

    Communication links via satellites are becoming available in Europe, both as part of the development of the telephone system and as special services aimed at data traffic. They offer the possibility of speeds between 50 kb/s and 2 Mb/s, without the problems and long term commitments of long distance land lines. Such links are provided by the PTT's as circuits which can be booked for variable periods, and have error rates which can be very low and well controlled. Problems in networking can arise from the satellite delay, particularly if errors occur in the local connections, and from the leased circuit and tariff philosophies of the PTT's. (Auth.)

  15. VLT/SINFONI OBSERVATIONS OF EUROPA: NEW INSIGHTS INTO THE SURFACE COMPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Ligier, N.; Poulet, F.; Carter, J.; Brunetto, R. [Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bât. 121, F-91405 Orsay cedex (France); Gourgeot, F., E-mail: nicolas.ligier@ias.u-psud.fr [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile (Chile)

    2016-06-01

    We present new insights into Europa’s surface composition on the global scale from linear spectral modeling of a high spectral resolution data set acquired during a ground-based observation campaign using SINFONI{sup 4}, an adaptive optics near-infrared instrument on the Very Large Telescope (ESO). The spectral modeling confirms the typical “bullseye” distribution of sulfuric acid hydrate on the trailing hemisphere, which is consistent with Iogenic sulfur ion implantation. However, the traditional hypothesis of the presence of sulfate salts on the surface of the satellite is challenged as Mg-bearing chlorinated species (chloride, chlorate, and perchlorate) are found to provide improved spectral fits. The derived global distribution of Mg-chlorinated salts (and particularly chloride) is correlated with large-scale geomorphologic units such as chaos and darker areas, thus suggesting an endogenous origin. Based on the 1.65 μ m water-ice absorption band shape and position, the surface temperature is estimated to be in the range 110–130 K, and water ice is found to be predominantly in its crystalline state rather than amorphous. While amorphous water ice exhibits a strong correlation with the expected intensity of the Ionian plasma torus bombardment, crystalline water ice is instead more associated with distinct geomorphological units. Endogenous processes such as jets and ice heating due to active geology may explain this relationship. Otherwise, no evidence of a correlation between grain size for the water ice and the sputtering rate has been detected so far.

  16. L’Europa del generale De Gaulle (The Europe of General de Gaulle

    Directory of Open Access Journals (Sweden)

    Lorenzo SCARCELLI

    2016-06-01

    Full Text Available De Gaulle at the head of the French resistance against the Nazis and after the war, he defended the sovereignty of France against the idea of a supranational Europe. De Gaulle at first opposed to a united Europe and the design of a Defence Community, then became its promoter, as he saw in a united Europe the mean to achieve the interests of France, through the project for a third force, between the United States and the Soviet Union. De Gaulle, worried that the EEC could lose its independence and become a satellite of the United States, sought a closer alliance between France and Germany, through the Fouchet Plan, in order to weaken the relationship between the European Community and the United States and create French primacy in European political cooperation. But with the advance of a supranational Europe, De Gaulle began the period of the Empty Chair. After the output of de Gaulle, the leaders of the EEC, designed a new path to realize the economic, political and military integration of Europe.

  17. Satellite switched FDMA advanced communication technology satellite program

    Science.gov (United States)

    Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

    1982-01-01

    The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

  18. Satellite constellation design and radio resource management using genetic algorithm.

    OpenAIRE

    Asvial, Muhamad.

    2003-01-01

    A novel strategy for automatic satellite constellation design with satellite diversity is proposed. The automatic satellite constellation design means some parameters of satellite constellation design can be determined simultaneously. The total number of satellites, the altitude of satellite, the angle between planes, the angle shift between satellites and the inclination angle are considered for automatic satellite constellation design. Satellite constellation design is modelled using a mult...

  19. Effects of comprehensive smoke-free legislation in Europe Efectos de la legislación antitabaco en Europa

    Directory of Open Access Journals (Sweden)

    Lucia Maria Lotrean

    2008-01-01

    Full Text Available This paper reviews data regarding the effects of the legislation banning smoking in enclosed public places, including workplaces, restaurants and bars which entered into force in several countries of Europe starting with the year 2004. The source of data is represented by articles and short information published in peer reviewed journals or in electronic format between the years 2005 and 2008. Highlights include a consideration of the effects of these laws on the attitudes of the population regarding their implementation, exposure to passive smoking in public places as well as the scientific evidence on the public health and economic impact of these laws. The results of smoking ban in public places observed in several parts of Europe support initiatives in many countries toward implementing smoke-free legislation, particularly those who have ratified the Framework Convention on Tobacco Control, which calls for legislation to reduce tobacco smoke pollution.Se revisaron datos sobre el impacto de las leyes que prohíben fumar en espacios públicos cerrados, incluyendo centros de trabajo, restaurantes y bares, las cuales entraron en vigor en varios países de Europa en 2004. La fuente de datos incluye artículos indexados y notas breves publicadas en revistas científicas o en formato electrónico entre 2005 y 2008. Los hallazgos incluyen una descripción del impacto de estas leyes sobre las actitudes de la población con respecto a su implementación, la exposición al humo de tabaco ambiental en espacios públicos cerrados, así como la evidencia científica sobre el impacto de estas leyes en la salud pública y en la economía. Los resultados de la prohibición de fumar en lugares públicos que se observaron en varios países de Europa confirman la importancia de promulgar iniciativas legislativas para crear ambientes libres de humo de tabaco en varios países del mundo, en particular en aquellos que han ratificado en Convenio Marco para el

  20. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  1. Atmospheric correction of satellite data

    Science.gov (United States)

    Shmirko, Konstantin; Bobrikov, Alexey; Pavlov, Andrey

    2015-11-01

    Atmosphere responses for more than 90% of all radiation measured by satellite. Due to this, atmospheric correction plays an important role in separating water leaving radiance from the signal, evaluating concentration of various water pigments (chlorophyll-A, DOM, CDOM, etc). The elimination of atmospheric intrinsic radiance from remote sensing signal referred to as atmospheric correction.

  2. Audio Satellites: Overhearing Everyday Life

    DEFF Research Database (Denmark)

    Kirkegaard, Jonas Rasmussen; Breinbjerg, M.; Højlund, M. K.

    2017-01-01

    around or displaced arbitrarily in a given landscape. In the web browser, the different sound streams from the individual satellites can be mixed together to form a cooperative soundscape. The project thus allows people to tune into and explore the overheard soundscape of everyday life in a collaborative...

  3. Electrophotometric observations of artificial satellites

    International Nuclear Information System (INIS)

    Vovchyk, Yeva; Blagodyr, Yaroslav; Kraynyuk, Gennadiy; Bilinsky, Andriy; Lohvynenko, Alexander; Klym, Bogdan; Pochapsky, Yevhen

    2004-01-01

    Problems associated with polarimetric observations of low Earth orbit artificial satellites as important solar system objects are discussed. The instrumentation (the optical and mechanical parts, the control and drive electronics, and the application software) for performing such observations is also described

  4. The Mobile Satellite Services Market.

    Science.gov (United States)

    Anderson, Samuel

    Mobile satellite (MSAT) technology is the basis for a new component of the telecommunications industry capable of providing services to small inexpensive subscriber terminals located almost any place in the world. The market for MSAT space segment capacity (bandwidth and power) is a natural monopoly that can be logically and technically…

  5. Launching the First Indian Satellite

    Indian Academy of Sciences (India)

    long run, this is not bad since it generates self-confidence and self-reliance - which in the final analysis are .... hopes to find some new X-ray sources. The second ... from the state of health of the satellite can be judged. A tracking network gives ...

  6. GOES-R: Satellite Insight

    Science.gov (United States)

    Fitzpatrick, Austin J.; Leon, Nancy J.; Novati, Alexander; Lincoln, Laura K.; Fisher, Diane K.

    2012-01-01

    GOES-R: Satellite Insight seeks to bring awareness of the GOES-R (Geostationary Operational Environmental Satellite -- R Series) satellite currently in development to an audience of all ages on the emerging medium of mobile games. The iPhone app (Satellite Insight) was created for the GOES-R Program. The app describes in simple terms the types of data products that can be produced from GOES-R measurements. The game is easy to learn, yet challenging for all audiences. It includes educational content and a path to further information about GOESR, its technology, and the benefits of the data it collects. The game features action-puzzle game play in which the player must prevent an overflow of data by matching falling blocks that represent different types of GOES-R data. The game adds more different types of data blocks over time, as long as the player can prevent a data overflow condition. Points are awarded for matches, and players can compete with themselves to beat their highest score.

  7. University Satellite Campus Management Models

    Science.gov (United States)

    Fraser, Doug; Stott, Ken

    2015-01-01

    Among the 60 or so university satellite campuses in Australia are many that are probably failing to meet the high expectations of their universities and the communities they were designed to serve. While in some cases this may be due to the demand driven system, it may also be attributable in part to the ways in which they are managed. The…

  8. Water Quality Monitoring by Satellite

    Science.gov (United States)

    Journal of Chemical Education, 2004

    2004-01-01

    The availability of abundant water resources in the Upper Midwest of the United States is nullified by their contamination through heavy commercial and industrial activities. Scientists have taken the responsibility of detecting the water quality of these resources through remote-sensing satellites to develop a wide-ranging water purification plan…

  9. "Quo vadis", Europa? Uma pergunta que não quer calar "Quo vadis", Europe? A question that will not go away

    Directory of Open Access Journals (Sweden)

    Sonia de Camargo

    2004-06-01

    Full Text Available Dois temas básicos são discutidos e examinados neste trabalho: a incorporação de dez novos membros aos quadros da União Européia e a constitucionalização de sua estrutura jurídico-institucional. Para tanto, proponho-me, de um lado, a reconstituir os passos político-institucionais que cobrem o período que vai de uma Europa do pós-guerra, fragmentada e enfraquecida, a uma Europa pós-Guerra Fria, pronta para se estender a todo o continente, processo que se abre em maio de 2004 com a incorporação de dez Estados vindos do Leste Europeu; de outro, a reproduzir o debate institucional entre uma Europa federal e uma Europa de Estados, o qual levou a que, em junho de 2003, fosse apresentado ao Conselho Europeu reunido em Salônica o projeto do novo Tratado da União e, em dezembro de 2003, fosse discutido, na Cúpula de Chefes de Estado da UE, reunida em Bruxelas, o texto da primeira Constituição para a Europa.Two basic themes are discussed and examined in this paper: the incorporation of ten new members into the European Union frame and the creation of institutional-legal structure supported by a Constitution. To do so, I propose, on one hand, to reconstitute the political-institutional steps which covered the period coming from post-war Europe, fragmented and weakened, to a post-Cold War Europe ready to spread throughout the continent. This process began in May 2004 with the incorporation of ten States of Eastern Europe. On the other hand, I intend to reproduce the institutional debate between a Federal Europe and a Europe of States, debate which conducted to the presentation to the European Council of the project of the new Treaty of the Union, which met in Salonika, in June 2003; second, to the discussion of the text of the first European Constitution, in the Summit of Heads of States of EU, held in Brussels, December 2003.

  10. Satellite-Based Precipitation Datasets

    Science.gov (United States)

    Munchak, S. J.; Huffman, G. J.

    2017-12-01

    Of the possible sources of precipitation data, those based on satellites provide the greatest spatial coverage. There is a wide selection of datasets, algorithms, and versions from which to choose, which can be confusing to non-specialists wishing to use the data. The International Precipitation Working Group (IPWG) maintains tables of the major publicly available, long-term, quasi-global precipitation data sets (http://www.isac.cnr.it/ ipwg/data/datasets.html), and this talk briefly reviews the various categories. As examples, NASA provides two sets of quasi-global precipitation data sets: the older Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and current Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG). Both provide near-real-time and post-real-time products that are uniformly gridded in space and time. The TMPA products are 3-hourly 0.25°x0.25° on the latitude band 50°N-S for about 16 years, while the IMERG products are half-hourly 0.1°x0.1° on 60°N-S for over 3 years (with plans to go to 16+ years in Spring 2018). In addition to the precipitation estimates, each data set provides fields of other variables, such as the satellite sensor providing estimates and estimated random error. The discussion concludes with advice about determining suitability for use, the necessity of being clear about product names and versions, and the need for continued support for satellite- and surface-based observation.

  11. Satellite Tags- Guam/CNMI EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  12. New Equipment Training Center-Satellite Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Satellite Facility is a 24-hour on-site military satellite transmission and downlink capability to Southwest Asia and all other military OCONUS and CONUS...

  13. Some European capabilities in satellite cinema exhibition

    Science.gov (United States)

    Bock, Wolfgang

    1990-08-01

    The likely performance envelope and architecture for satellite cinema systems are derived from simple practical assumptions. A case is made for possible transatlantic cooperation towards establishing a satellite cinema standard.

  14. Multiple Usage of Existing Satellite Sensors (PREPRINT)

    National Research Council Canada - National Science Library

    Keeney, James T

    2006-01-01

    .... Space offers a near-perfect vacuum to operate a passive or active sensor. Volume, mass and power on satellites is limited and risk management approaches tended to remove such sensors from satellite systems...

  15. Multiple Usage of Existing Satellite Sensors

    National Research Council Canada - National Science Library

    Keeney, James T

    2006-01-01

    .... Space offers a near-perfect vacuum to operate a passive or active sensor. Volume, mass and power on satellites is limited and risk management approaches tended to remove such sensors from satellite systems...

  16. Biophysical applications of satellite remote sensing

    CERN Document Server

    Hanes, Jonathan

    2014-01-01

    Including an introduction and historical overview of the field, this comprehensive synthesis of the major biophysical applications of satellite remote sensing includes in-depth discussion of satellite-sourced biophysical metrics such as leaf area index.

  17. Clock Management Data Analysis for Satellite Communications

    National Research Council Canada - National Science Library

    Gross, Rachel; Melkers, Raimond

    2005-01-01

    The U.S. Naval Research Laboratory has installed GPS-based timing systems in several Defense Satellite Communication System "DSCS-III" satellite communication facilities to support the Single Channel Transponder "SCT" program...

  18. Core Flight System Satellite Starter Kit

    Data.gov (United States)

    National Aeronautics and Space Administration — The Core Flight System Satellite Starter Kit (cFS Kit) will allow a small satellite or CubeSat developer to rapidly develop, deploy, test, and operate flight...

  19. RFP for the italien satellite AGILE

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Riis, Troels

    1999-01-01

    The document descibes the ASC Star Tracker (performance, functionality, requirements etc.) to the Italian satellite AGILE.......The document descibes the ASC Star Tracker (performance, functionality, requirements etc.) to the Italian satellite AGILE....

  20. Highly Enhanced Risk Management Emergency Satellite

    DEFF Research Database (Denmark)

    Dalmeir, Michael; Gataullin, Yunir; Indrajit, Agung

    HERMES (Highly Enhanced Risk Management Emergency Satellite) is potential European satellite mission for global flood management, being implemented by Technical University Munich and European Space Agency. With its main instrument - a reliable and precise Synthetic Aperture Radar (SAR) antenna...