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Sample records for allen probes mission

  1. Recent Results from the Relativistic Electron Proton Telescope (REPT) onboard the Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.; Elkington, S. R.; Hoxie, V. C.; Li, X.; Spence, H. E.

    2013-05-01

    We describe recent results from the REPT instruments on board Van Allen Probes mission launched on 30 August 2012. The twin spacecraft comprising the Van Allen probes mission are identically instrumented and carry a comprehensive suite of sensors characterizing magnetospheric charged particle populations, electric and magnetic fields and plasma waves. The REPT instruments comprise a well-shielded silicon solid state detector stack, with a state of the art electronics and measure electrons of ~1.5 to > 20 MeV and protons of ~17 to > 100 MeV. The instruments were commissioned 3 days after launch and continue to provide high quality measurements. We describe the Van Allen probes and the REPT instrument and report on the new and unexpected features of the outer zone electron populations observed by REPT.

  2. Science Highlights from the RBSP-ECT Particle Instrument Suite on NASA's Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Spence, Harlan

    2014-05-01

    The NASA Van Allen Probes mission includes an instrument suite known as the Radiation Belt Storm Probes (RBSP) - Energetic Particle, Composition, and Thermal Plasma (ECT) suite. RBSP-ECT contains a well-proven complement of particle instruments to ensure the highest quality measurements ever made in the radiation belts and the inner magnetosphere. The coordinated RBSP-ECT particle measurements, analyzed in combination with fields and waves observations and state of-the-art theory and modeling, provide new understanding on the acceleration, global distribution, and variability of radiation belt electrons and ions, key science objectives of NASA's Living With a Star program and the Van Allen Probes mission. The RBSP-ECT suite consists of three highly-coordinated instruments: the Helium Oxygen Proton Electron (HOPE) spectrometer, the Magnetic Electron Ion Spectrometer (MagEIS), and the Relativistic Electron Proton Telescope (REPT). Collectively these three instrument types cover comprehensively the full electron and ion spectra from one eV to 10's of MeV with sufficient energy resolution, pitch angle coverage and resolution, and with composition measurements in the critical energy range up to 50 keV and also from a few to 50 MeV/nucleon. All three instruments are based on measurement techniques proven in the radiation belts, then optimized to provide unambiguous separation of ions and electrons and clean energy responses even in the presence of extreme penetrating background environments. In this presentation, we summarize overall ECT science goals and then show scientific results derived from the ECT suite on the dual Van Allen Probes spacecraft to date. Mission operations began only in late October 2012, and we have now achieved significant results. Results presented here will include substantial progress toward resolving primary Van Allen Probes science targets, such as: the relative role of localized acceleration versus transport-generated particle acceleration

  3. Van Allen Probes Mission Space Academy: Educating middle school students about Earth's mysterious radiation belts

    NASA Astrophysics Data System (ADS)

    Butler, L.; Turney, D.; Matiella Novak, A.; Smith, D.; Simon, M.

    2013-12-01

    How's the weather in space? Why on Earth did NASA send two satellites above Earth to study radiation belts and space weather? To learn the answer to questions about NASA's Van Allen Probes mission, 450 students and their teachers from Maryland middle schools attended Space Academy events highlighting the Van Allen Probes mission. Sponsored by the Applied Physics Laboratory (APL) and Discovery Education, the events are held at the APL campus in Laurel, MD. Space Academies take students and teachers on behind-the-scenes exploration of how spacecraft are built, what they are designed to study, and introduces them to the many professionals that work together to create some of NASA's most exciting projects. Moderated by a public relations representative in the format of an official NASA press conference, the daylong event includes a student press conference with students as reporters and mission experts as panelists. Lunch with mission team members gives students a chance to ask more questions. After lunch, students don souvenir clean room suits, enjoy interactive science demonstrations, and tour APL facilities where the Van Allen Probes were built and tested before launch. Students may even have an opportunity to peek inside a clean room to view spacecraft being assembled. Prior to the event, teachers are provided with classroom activities, lesson plans, and videos developed by APL and Discovery Education to help prepare students for the featured mission. The activities are aligned to National Science Education Standards and appropriate for use in the classroom. Following their visit, student journalists are encouraged to write a short article about their field trip; selections are posted on the Space Academy web site. Designed to engage, inspire, and influence attitudes about space science and STEM careers, Space Academies provide an opportunity to attract underserved populations and emphasize that space science is for everyone. Exposing students to a diverse group of

  4. A Union of Inner Magnetosphere Data from the Van Allen Probes and Related Missions at NASA's Space Physics Data Facility (SPDF)

    NASA Astrophysics Data System (ADS)

    McGuire, R. E.; Bilitza, D.; Candey, R. M.; Chimiak, R. A.; Cooper, J. F.; Garcia, L. N.; Harris, B. T.; Johnson, R. C.; King, J. H.; Kovalick, T. J.; Lal, N.; Leckner, H. A.; Liu, M. H.; Papitashvili, N. E.; Roberts, D.

    2013-12-01

    A wide range of current, public, science-quality particle and field data from the Van Allen Probes and related missions is being ingested, archived and served to the international science community by SPDF. As an active heliophysics archive, SPDF now serves some eighty Level-2 (and increasingly Level-3) data products that fully span the range of measurements from particles-plasma (RBSPICE, ECT) through magnetic-electric fields and waves (EMFISIS, EFW). This coherent collection of mission data, in a standard format (CDF) with standard metadata, is available through SPDF's CDAWeb user interface, CDAWeb's web services and associated APIs for IDL and Matlab users, as well as through direct FTP/HTTP download access supplemented with orbit displays through our SSCWeb and 4D Orbit Viewer services and HDP/VSPO direct links to investigator sites/resources. With the dedicated work of the project and instrument teams, these data products are of increasingly high quality and typically current within 2 months or less. Having this range of data in CDAWeb makes comparison of data among instruments and spacecraft much easier, as well as comparisons and analysis of these data with current data from other missions including THEMIS, TWINS, Cluster, ACE, Wind and now >120 ground magnetometer stations. In addition, SPDF supports data from the BARREL Antarctic balloon program and recent data from instruments on the NOAA GOES spacecraft. SPDF will also support public data from the MMS mission when launched in later 2014.

  5. Multi-Point Observations of the Inner Magnetosphere from the Van Allen Probes and Related Missions at NASA's Space Physics Data Facility (SPDF)

    NASA Astrophysics Data System (ADS)

    McGuire, R. E.; Bilitza, D.; Candey, R. M.; Chimiak, R.; Cooper, J. F.; Garcia, L. N.; Harris, B. T.; Johnson, R. C.; Kovalick, T.; Lal, N.; Leckner, H.; Liu, M.; Papitashvili, N. E.; Roberts, D. A.

    2014-12-01

    A wide range of current, public, science-quality particle and field data from the Van Allen Probes and related missions is ingested, archived and served to the international science community by SPDF. As an active heliophysics final archive, SPDF now serves 100+ Level-2 and Level-3 data products that fully span the range of measurements from particles and plasmas (RBSPICE, ECT) through magnetic-electric fields and waves (EMFISIS, EFW). This collection of mission data (in a standard CDF format with standard ISTP/SPDF) is available through SPDF's CDAWeb user interface, through CDAWeb's web services and associated APIs for IDL and Matlab users, and through direct FTP/HTTP download access. These data are supplemented with orbit displays through our SSCWeb and 4D Orbit Viewer services and HDP/VSPO direct links to investigator sites/resources. This range of data in CDAWeb makes comparison of data among instruments and spacecraft much easier, as well as comparisons and analysis of these data with current data from other missions including THEMIS, TWINS, Cluster, ACE, Wind and now >120 ground magnetometer stations. In addition, SPDF supports data from the BARREL Antarctic balloon program and new data from instruments on the NOAA GOES and POES spacecraft. SPDF will add public data from the MMS mission to this collection when launched in 2015.

  6. Van Allen Probes Science Gateway: A Centralized Data Access Point

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Ukhorskiy, A. Y.; Sotirelis, T.; Stephens, G. K.; Kessel, R.; Potter, M.

    2015-12-01

    The Van Allen Probes Science Gateway acts a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the Van Allen Probes Space Weather data to users. Over the past years, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes science and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including, simple time series, data plotted as a function of orbital location, and time versus L-Shell, capability of visualizing data from both probes (A & B) on the same plot. In cooperation with all Van Allen Probes Instrument SOCs, the Science Gateway will soon be able to serve higher level data products (Level 3), and to visualize them via the above mentioned HTML5 interface. Users will also be able to create customized CDF files on the fly.

  7. MIDL: A Demonstration of Multi-Mission Analysis of Charged Particle Data From Van Allen Probes and the Juno Earth Flyby

    NASA Astrophysics Data System (ADS)

    Brown, L. E.; Mitchell, D. G.; Paranicas, C.; Mauk, B.; Lanzerotti, L. J.; Vandegriff, J. D.

    2013-12-01

    At the present time, a fleet of heliosphere spacecraft is producing an unprecedented number of measurements of charged particles and magnetic fields throughout the solar system - from Mercury to the local interstellar medium. It is vital to have a flexible and efficient data browsing, discovery, and analysis environment to navigate this wealth of information. We present a multi-mission tool for quick look data viewing and analysis. In addition to a rich tool and feature set, MIDL3 (Mission Independent Data Layer - 3rd version) provides environments to cater to different user classes from instrument team engineers, to team scientists, to the general science community. Furthermore, MIDL3 adds a new, highly interactive, end-user visualization environment for rapid browsing and exploration of science and engineering data. Like AMDA and MAPSVIEW, MIDL has functioned for Cassini plasma and particle data as a highly successful platform for inter-comparing different instruments/sensors with minimal preparation work on the part of the user. We present a demonstration of simultaneous analysis of the JUNO Earth flyby (October 9, 2013) data from the JEDI instruments and Van Allen Probes data from the RBSPICE instruments. Since these two instrument sets share a very similar design (see presentations by C Paranicas, et al. and J Manwiler, et al. at this conference for details) we anticipate important results from this unique opportunity to compare measurements of energetic electrons and ions made by six telescopes each for the five similar instruments on three spacecraft within Earth's magnetosphere.

  8. NASA's RBSP-ECT Science Investigation of the Van Allen Probes Mission: Highlights of the Prime Mission Phase, Data Access Overview, and Opportunities to Collaborate in the Extended Mission Phase

    NASA Astrophysics Data System (ADS)

    Smith, S. S.; Friedel, R. H.; Larsen, B.; Reeves, G.; Spence, H. E.

    2015-12-01

    In this poster, we present a summary of access to the data products of the Radiation Belt Storm Probes - Energetic Particle Composition, and Thermal plasma (RBSP-ECT) suite of NASA's Van Allen Probes mission. The RBSP-ECT science investigation (http://rbsp-ect.sr.unh.edu) measures comprehensively the near-Earth charged particle environment in order to understand the processes that control the acceleration, global distribution, and variability of radiation belt electrons and ions. RBSP-ECT data products derive from the three instrument elements that comprise the suite, which collectively covers the broad energies that define the source and seed populations, the core radiation belts, and also their highest energy ultra-relativistic extensions. These RBSP-ECT instruments include, from lowest to highest energies: the Helium, Oxygen, Proton, and Electron (HOPE) sensor, the Magnetic Electron and Ion Spectrometer (MagEIS), and the Relativistic Electron and Proton Telescope (REPT). We provide a brief overview of their principles of operation, as well as a description of the Level 2-3 data products that the HOPE, MagEIS, and REPT instruments produce, both separately and together. We provide a summary of how to access these RBSP-ECT data products at our Science Operation Center and Science Data Center (http://www.rbsp-ect.lanl.gov/rbsp_ect.php ) as well as caveats for their use. Finally, in the spirit of efficiently and effectively promoting and encouraging new collaborations, we present a summary of past publications, current studies, and opportunities for your future participation in RBSP-ECT extended mission phase science.

  9. The Evolving Space Weather System—Van Allen Probes Contribution

    NASA Astrophysics Data System (ADS)

    Zanetti, L. J.; Mauk, B. H.; Fox, N. J.; Barnes, R. J.; Weiss, M.; Sotirelis, T. S.; Raouafi, N.-E.; Kessel, R. L.; Becker, H. N.

    2014-10-01

    The overarching goal and purpose of the study of space weather is clear—to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800s to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA's Van Allen Probes' twin pair of satellites, launched in August of 2012 and orbiting directly through Earth's severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP), was renamed soon after launch to honor the discoverer of Earth's radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes are one part of NASA's Living With a Star program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions, and their effects on the geospace and Earth environment.

  10. Van Allen Probes: Resolving Fundamental Physics with Practical Consequences

    NASA Astrophysics Data System (ADS)

    Ukhorskiy, Aleksandr; Sibeck, David; Fox, Nicola; Mauk, Barry; Kessel, Ramona

    The Van Allen Probes twin spacecraft were launched on 30 August 2012 into nearly identical, 1.1 x 5.8 Re elliptical, low inclination (10°) Earth orbits with one of the two spacecraft lapping the other about every 2.5 months. The goal of the mission is to provide understanding of how populations of relativistic electrons and penetrating ions in space form or change in response to variable inputs of energy from the Sun. In this paper we overview the new understanding and discoveries of the Van Allen Probes science investigations since the operational mission began on 1 November 2012, which include formation of multiple coherently ordered structures within the outer electron belt and new persistent “zebra stripes” in the inner electron belt.

  11. Van Allen Probes Science Gateway and Space Weather Data Processing

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2014-12-01

    The Van Allen Probes Science Gateway acts as a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the VAP Space Weather data to users. Over the past year, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes summary and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including simple time series, data plotted as a function of orbital location, and time versus L-Shell. We discuss the new Van Allen Probes Science Gateway and the Space Weather Data Pipeline.

  12. Global empirical models of plasmaspheric hiss using Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Spasojevic, M.; Shprits, Y. Y.; Orlova, K.

    2015-12-01

    Plasmaspheric hiss is a whistler-mode emission that permeates the Earth's plasmasphere and is a significant driver of energetic electron losses through cyclotron resonant pitch angle scattering. The Electric and Magnetic Field Instrument Suite and Integrated Science instrument on the Van Allen Probes mission provides vastly improved measurements of the hiss wave environment including continuous measurements of the wave magnetic field cross-spectral matrix and enhanced low-frequency coverage. Here, we develop empirical models of hiss wave intensity using two years of Van Allen Probes data. First, we describe the construction of the hiss database. Then, we compare the hiss spectral distribution and integrated wave amplitude obtained from Van Allen Probes to those previously extracted from the Combined Release and Radiation Effects Satellite mission. Next, we develop a cubic regression model of the average hiss magnetic field intensity as a function of Kp, L, magnetic latitude, and magnetic local time. We use the full regression model to explore general trends in the data and use insights from the model to develop a simplified model of wave intensity for straightforward inclusion in quasi-linear diffusion calculations of electron scattering rates.

  13. What have we learned about the energetic particle dynamics in the inner belt and slot region from Van Allen Probes and CSSWE missions?

    NASA Astrophysics Data System (ADS)

    Li, Xinlin; Baker, Daniel N.; Kanekal, Shrikanth; Fennell, Joseph; Selesnick, Richard; Claudepierre, Seth; Blake, Bernard; Zhao, Hong; Jaynes, Allison

    2016-07-01

    Comprehensive measurements of energetic protons (10s of MeV) in the inner belt (L<2) and slot region (2Allen Probes, in a geo-transfer-like orbit, revealed new features of these energetic protons in terms of their spectrum distribution, spatial distribution, pitch angle distribution, and their different source populations. Concurrent measurements from the Relativistic Electron-Proton Telescope integrated little experiment (REPTile) on board the Colorado Student Space Weather Experiment (CSSWE) CubeSat, in a highly inclined low Earth orbit, demonstrated that there exist sub-MeV electrons in the inner belt and their flux level is orders of magnitude higher than the background associated with the inner belt protons, while higher energy electron (>1.6 MeV) measurements cannot be distinguished from the background. Analysis on sub-MeV electrons data in the inner belt and slot region from the Magnetic Electron Ion Spectrometer (MagEIS) on board Van Allen Probes revealed rather complicated pitch angle distribution of these energetic electrons, with the 90 deg-minimum (butterfly) pitch angle distribution dominating near the magnetic equator. These are part of a summary of the most recent measurements and understanding of the dynamics of energetic particles in the inner zone and slot region to be exhibited and discussed in this presentation.

  14. Mission Specialist (MS) Allen experiments with beverage on middeck

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Mission Specialist (MS) Allen, using beverage container and drinking straw, experiments with microgravity chararcteristics of orange juice on middeck in front of the Development Flight Instrument (DFI) unit and forward lockers. Allen laughes as he watches the results of his experimentation.

  15. Observations of Whistler-Mode Chorus with Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Kurth, William; Hospodarsky, George; Santolik, Ondrej; Kletzing, Craig; Bounds, Scott

    2014-10-01

    The Van Allen Probes mission provides an excellent opportunity to observe whistler-mode chorus and its role in the radiation belts. The plasma wave instrument on the two probes, called Waves, includes six identical waveform receivers covering the frequency range from 10 Hz to 12 kHz. The instrument measures three orthogonal magnetic field components and three orthogonal electric field components of waves. This complement supports wave-normal and Poynting flux analyses of chorus as well as other wave modes that interact with radiation belt particles. Extensive use of burst modes provides multicomponent waveforms enabling the study of individual chorus elements, including their substructure. The early-mission publications confirm the importance of chorus to the local acceleration of electrons in the outer radiation belts. The orbital precession of the twin Van Allen Probes through a complete range of local times now allows for a new survey of the distribution of chorus emissions. Hence, we now have the tools to study chorus from the nonlinear growth in chorus element substructures through synoptic studies of the near-equatorial occurrence of chorus out to a distance of approximately 5.8 Earth radii.

  16. Geomagnetic Storms and EMIC waves: Van Allen Probe observations

    NASA Astrophysics Data System (ADS)

    Wang, Dedong; Yuan, Zhigang; Yu, Xiongdong; Huang, Shiyong; Deng, Xiaohua; Zhou, Meng; Li, Haimeng

    2016-04-01

    Electromagnetic Ion Cyclotron (EMIC) waves are believed to play a crucial role in the dynamics of ring current ions and radiation belt electrons, especially during geomagnetic storms. However, there is little consensus on which phase of the storm is more favorable for the generation of EMIC waves. Utilizing the data from magnetometer instrument of EMFISIS suite on board Van Allen Probe A, the occurrences of EMIC waves during geomagnetic storms are investigated in this paper. 76 storms were identified during the period under research, from 8 September 2012 to 30 April 2014, when the apogee of Van Allen Probe A covered all the MLT sectors. 50 of the 76 storms observed 124 EMIC wave events, of which 80 are found in the recovery phase, more than those observed in the main phase. Evolution of the distribution characteristics of EMIC waves respect to L and MLT in different geomagnetic phases is investigated, which is found to be consistent with that of the plasmasphere. These results are different from those derived by the observations of the CRRES satellite. The different results may result from the different orbit coverage of the two different satellite missions or from the different activity level of the magnetosphere during the different periods. Few EMIC waves in the dayside sector during the pre-onset periods are observed. It is implied that, to the generation of EMIC waves, the effect of solar wind dynamic pressure in the inner magnetosphere is not so significant as that in the outer magnetosphere.

  17. Spacecraft-level verification of the Van Allen Probes' RF communication system

    NASA Astrophysics Data System (ADS)

    Crowne, M. J.; Srinivasan, D.; Royster, D.; Weaver, G.; Matlin, D.; Mosavi, N.

    This paper presents the verification process, lessons learned, and selected test results of the radio frequency (RF) communication system of the Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP). The Van Allen Probes mission is investigating the doughnut-shaped regions of space known as the Van Allen radiation belts where the Sun interacts with charged particles trapped in Earth's magnetic field. Understanding this dynamic area that surrounds our planet is important to improving our ability to design spacecraft and missions for reliability and astronaut safety. The Van Allen Probes mission features two nearly identical spacecraft designed, built, and operated by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) for the National Aeronautics and Space Administration (NASA). The RF communication system features the JHU/APL Frontier Radio. The Frontier Radio is a software-defined radio (SDR) designed for spaceborne communications, navigation, radio science, and sensor applications. This mission marks the first spaceflight usage of the Frontier Radio. RF ground support equipment (RF GSE) was developed using a ground station receiver similar to what will be used in flight and whose capabilities provided clarity into RF system performance that was previously not obtained until compatibility testing with the ground segments. The Van Allen Probes underwent EMC, acoustic, vibration, and thermal vacuum testing at the environmental test facilities at APL. During this time the RF communication system was rigorously tested to ensure optimal performance, including system-level testing down to threshold power levels. Compatibility tests were performed with the JHU/APL Satellite Communication Facility (SCF), the Universal Space Network (USN), and the Tracking and Data Relay Satellite System (TDRSS). Successful completion of this program as described in this paper validated the design of the system and demonstrated that it will be able to me

  18. Ion spectral structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Ferradas, C.; Zhang, J.; Spence, H. E.; Kistler, L. M.; Larsen, B.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.

    2015-12-01

    During the last decades several missions have recorded the presence of dynamic spectral features of energetic ions in the inner magnetosphere. Previous studies have reported single "nose-like" structures occurring alone and simultaneous nose-like structures (up to three). These ion structures are named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. They constitute the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. The HOPE mass spectrometer onboard the Van Allen Probes measures energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet, where these ion structures are observed. We present a statistical study of nose-like structures, using 2-years measurements from the HOPE instrument. The results provide important details about the spatial distribution (dependence on geocentric distance), spectral features of the structures (differences among species), and geomagnetic conditions under which these structures occur.

  19. The Van Allen Probes first year of discovery and understanding (Invited)

    NASA Astrophysics Data System (ADS)

    Mauk, B.; Fox, N. J.; Sibeck, D. G.; Kanekal, S. G.; Kessel, R.

    2013-12-01

    The Van Allen Probes twin spacecraft were launched on 30 August 2012 and inserted into nearly identical, 1.1 x 5.8 RE elliptical, low inclination (10°), 9-hour period Earth orbits with one of the two spacecraft lapping the other about every 2.5 months. The discoveries and understandings achieved by the Van Allen Probes science investigations since the operational mission began on 1 November 2012 are all that we had hoped. The probes are discovering new and unanticipated behaviors of the radiation belts, for example coherently ordered multiple structures, and are revealing quantitatively how and why those behaviors occur. The probes are answering definitely outstanding important questions regarding Earth's inner magnetosphere, for example, the extent to which and the processes by which local acceleration contributes to creation of the belts. With its close 2-month coordination with the BARREL mission of opportunity array of Antarctic balloons, the Probes are contributing greatly to our understanding of the causes of radiation belt loss and the relationship between high and low altitude radiation belt phenomena. In this overview presentation we assess the discoveries and findings of the Van Allen Probes mission following its first year of operation, and provide a guide to the activities and achievements anticipated over the next year.

  20. Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, Irina; Kurth, William; Spasojevic, Maria; Shprits, Yuri

    2016-07-01

    We present the Neural-network-based Upper-hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made onboard NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, f_{uhr}, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the EMFISIS instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.

  1. Radition belt dynamics : Recent results from van Allen Probes and future observations from CeREs

    NASA Astrophysics Data System (ADS)

    Kanekal, Shrikanth; O'Brien, Paul; Baker, Daniel N.; Ogasawara, Keiichi; Fennell, Joseph; Christian, Eric; Claudepierre, Seth; Livi, Stefano; Desai, Mihir; Li, Xinlin; Jaynes, Allison; Turner, Drew; Jones, Ashley; Schiller, Quintin

    2016-07-01

    We describe recent observations of the Earth's radiation belts made by instruments on board the Van Allen Probes mission, particularly the Relativistic Electron Proton Telescope (REPT) and the Magnetic Electron Ion spectrometer (MagEIS). These observations have significantly advanced our understanding of terrestrial radiation belt dynamics. The Van Allen Probes mission comprises two identically instrumented spacecraft which were launched 31 August, 2012 into low-inclination lapping equatorial orbits. The orbit periods are about 9 hours, with perigees and apogees of of ~600 km and 5.8 RE respectively. We discuss the new scientific findings of the Van Allen Probes mission regarding the physics of energization and loss of relativistic electrons and their implications for future low-cost missions, especially CubeSats. We describe the CeREs (a Compact Radiation belt Explorer) CubeSat mission currently being built at the Goddard Space Flight Center, and carrying on board, an innovative instrument, the Miniaturized Electron Proton Telescope (MERiT). The MERiT is a compact low-mass low-power instrument measuring electrons from a few keV to tens of MeV in multiple differential channels. MERiT is optimized to measure electron microbursts with a high time resolution of a few milliseconds. We present and discuss possible future scientific contributions from CeREs.

  2. Gradual Diffusion and Punctuated Phase Space Density Enhancements of Highly Relativistic Electrons: Van Allen Probes Observations

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Jaynes, A. N.; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, H. E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.

    2014-01-01

    The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E (is) approximately 10MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L (is) approximately 4.0 +/- 0.5). This reveals graphically that both 'competing' mechanisms of multi-MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

  3. Astronaut Andrew M. Allen, mission commander, sets up systems for a television downlink on the

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-75 ONBOARD VIEW --- Astronaut Andrew M. Allen, mission commander, sets up systems for a television downlink on the flight deck of the Space Shuttle Columbia. Allen was joined by four other astronauts and an international payload specialist for more than 16 days of research aboard Columbia. The photograph was taken with a 70mm handheld camera.

  4. NASA's Radiation Belt Storm Probe Mission

    NASA Technical Reports Server (NTRS)

    Sibeck, David G.

    2011-01-01

    NASA's Radiation Belt Storm Probe (RBSP) mission, comprising two identically-instrumented spacecraft, is scheduled for launch in May 2012. In addition to identifying and quantifying the processes responsible for energizing, transporting, and removing energetic particles from the Earth's Van Allen radiation, the mission will determine the characteristics of the ring current and its effect upon the magnetosphere as a whole. The distances separating the two RBSP spacecraft will vary as they move along their 1000 km altitude x 5.8 RE geocentric orbits in order to enable the spacecraft to separate spatial from temporal effects, measure gradients that help identify particle sources, and determine the spatial extent of a wide array of phenomena. This talk explores the scientific objectives of the mission and the manner by which the mission has been tailored to achieve them.

  5. Van Allen Probe Charging During the St. Patrick's Day Event

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Minow, J. I.

    2015-01-01

    The geomagnetic storms on and around March 17, 2015 marked the largest storms seen in the declining phase of the solar cycle to date. We use the Helium Oxygen Proton Electron (HOPE) mass spectrometer on board the Van Allen Probe - A and B satellites to study in detail the charging effects seen on these spacecraft during this time. Ion particle flux data provides information on the magnitude of the charging events using the ion line charging signature due to low energy ions accelerated by the spacecraft potential. Electron flux observations are used to correlate the charging environment with variations in spacecraft potential through the event. We also investigate the density and temperature of ions and electrons during the time of the charging event.

  6. New results from the Colorado CubeSat and comparison with Van Allen Probes data

    NASA Astrophysics Data System (ADS)

    Li, X.

    2013-05-01

    The Colorado Student Space Weather Experiment (CSSWE) is a 3-unit (10cm x 10cm x 30cm) CubeSat mission funded by the NSF, launched into a highly inclined (650) low-Earth (490km x 790km) orbit on 09/13/12 as a secondary payload under NASA's Educational Launch of Nanosatellites (ELaNa) program. CSSWE contains a single science payload, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), which is a simplified and miniaturized version of the Relativistic Electron and Proton Telescope (REPT) built at the Laboratory for Atmospheric and Space Physics (LASP) of University of Colorado for NASA/Van Allen Probes mission, which consists of two identical spacecraft, launched on 08/30/12, that traverse the heart of the radiation belts in a low inclination (100) orbit. REPTile is designed to measure the directional differential flux of protons ranging from 9 to 40 MeV and electrons from 0.5 to >3.3 MeV. Three-month science mission (full success) was completed on 1/05/13. We are now into the extended mission phase, focusing on data analysis and modeling. REPTile measures a fraction of the total population that has small enough equatorial pitch angles to reach the altitude of CSSWE, thus measuring the precipitating population as well as the trapped population. These measurements are critical for understanding the loss of outer radiation belt electrons. New results from CSSWE and comparison with Van Allen Probes data will be presented. The CSSWE is also an ideal class project, involving over 65 graduate and undergraduate students and providing training for the next generation of engineers and scientists over the full life-cycle of a satellite project.

  7. James Van Allen and His Namesake NASA Mission

    NASA Astrophysics Data System (ADS)

    Baker, D. N.; Hoxie, V. C.; Jaynes, A.; Kale, A.; Kanekal, S. G.; Li, X.; Reeves, G. D.; Spence, H. E.

    2013-12-01

    In many ways, James A. Van Allen defined and "invented" modern space research. His example showed the way for government-university partners to pursue basic research that also served important national and international goals. He was a tireless advocate for space exploration and for the role of space science in the spectrum of national priorities.

  8. Radiation Belt Storm Probe (RBSP) Mission

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Fox, N.; Grebowsky, J. M.; Mauk, B. H.

    2009-01-01

    Scheduled to launch in May 2012, NASA's dual spacecraft Living With a Star Radiation Belt Storm Probe mission carries the field and particle instrumentation needed to determine the processes that produce enhancements in radiation belt ion and electron fluxes, the dominant mechanisms that cause the loss of relativistic electrons, and the manner by which the ring current and other geomagnetic phenomena affect radiation belt behavior. The two spacecraft will operate in low-inclination elliptical lapping orbits around the Earth, within and immediately exterior to the Van Allen radiation belts. During course of their two year primary mission, they will cover the full range of local times, measuring both AC and DC electric and magnetic fields to 10kHz, as well as ions from 50 eV to 1 GeV and electrons with energies ranging from 50 eV to 10 MeV.

  9. Inner zone electron radial diffusion coefficients - An update with Van Allen Probes MagEIS data

    NASA Astrophysics Data System (ADS)

    O'Brien, Paul; Fennell, Joseph; Guild, Timothy; Mazur, Joseph; Claudepierre, Seth; Clemmons, James; Turner, Drew; Blake, Bernard; Roeder, James

    2016-07-01

    Using MagEIS data from NASA's recent Van Allen Probes mission, we estimate the quiet-time radial diffusion coefficients for electrons in the inner radiation belt and slot, for energies up to ~700 keV. We provide observational evidence that energy diffusion is negligible. The main dynamic processes, then, are radial diffusion and elastic pitch angle scattering. We use a coordinate system in which these two modes of diffusion are separable. Then we integrate over pitch angle to obtain a field line content whose dynamics consist of radial diffusion and loss to the atmosphere. We estimate the loss timescale from periods of exponential decay in the time series. We then estimate the radial diffusion coefficient from the temporal and radial variation of the field line content. We show that our diffusion coefficients agree well with previously determined values. Our coefficients are consistent with diffusion by electrostatic impulses, whereas outer zone radial diffusion is thought to be dominated by electromagnetic fluctuations.

  10. Radiation Belt Storm Probe Mission Trailer

    NASA Video Gallery

    With launch scheduled for 2012, the Radiation Belt Storm Probe (RBSP) are two identical spacecraft that will investigate the doughnut shaped Van Allen radiation belts, the first discovery of the sp...

  11. Space Weather data processing and Science Gateway for the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2013-12-01

    A near real-time data processing pipeline for the Space Weather broadcast data from the Van Allen Probes is presented. The Van Allen Probes broadcasts a sub-set of the science data in real-time when not downlinking the principal science data. This broadcast is received by several ground stations and relayed to APL in near real time to be ingested into the space weather processing pipeline. This pipeline processes the available level zero space weather data into higher level science data products. These products are made available to the public via the Van Allen Probes Science Gateway website (http://athena.jhuapl.edu). The website acts as pivotal point though which all other instrument SOC's can be accessed. Several other data products (e.g KP/DST indices) and tools (e.g orbit calculator) are made also available to the general public.

  12. Magnetospheric Observations from JUNO and the Van Allen Probes on Oct 9, 2013 (Invited)

    NASA Astrophysics Data System (ADS)

    Thorne, R. M.

    2013-12-01

    During the Earth Flyby of JUNO on October 9, 2013, the two Van Allen probes will make observations of magnetospheric waves and particles from a near equatorial orbit with apogee near 5.8 RE in the dusk sector. Both the MagEIS and the RBSPICE instruments on the Van Allen probes will measure the radiation belt and the ring current population over an energy range similar to the JEDI instrument on JUNO, which will be used to provide an important calibration of JEDI during the flyby. Measurements at considerable higher energy obtained from the REPT and RPS instruments on the Van Allen probes can be used to investigate the sensitivity of several instruments and other critical components on JUNO to the type of high-energy penetrating particles, to which the satellite will be exposed after orbital insertion in the Jovian magnetosphere. Several other JUNO instruments such as MAG and WAVES will be operational during the flyby allowing comparison with similar measurement on the Van Allen probes. Highlights of the coordinated observations obtained during the JUNO Earth flyby will be presented.

  13. Saturn orbiter dual probe mission

    NASA Technical Reports Server (NTRS)

    Rudd, R. P.

    1978-01-01

    The described Saturn orbiter dual probe mission and spacecraft combines three systems into a multi-purpose Saturn exploration package. The spacecraft consists of: (1) Saturn orbiter; (2) Saturn probe; and (3) Titan probe or lander. This single spacecraft provides the capability to conduct in situ measurements of the Saturn and Titan atmospheres, and, possibly the Titan surface, as well as a variety of remote sensing measurements. The remote sensing capabilities will be used to study the surfaces, interiors and environments of Saturn's satellites, the rings of Saturn, Saturn's magnetosphere, and synoptic properties of Saturn's atmosphere.

  14. Plasma Wave Measurements in Earth's Magnetosphere by Juno, Van Allen Probes, and Cluster

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Hospodarsky, G. B.; Bolton, S. J.; Gurnett, D. A.; Santolik, O.; Kletzing, C.; Thorne, R. M.; Pickett, J. S.

    2013-12-01

    On October 9, 2013, Juno will fly within about 550 km of Earth in the process of executing a gravity assist on its way to its eventual arrival at Jupiter in July 2016. Since this will be the only magnetospheric plasma regime Juno will sample prior to arrival at Jupiter, it presents both engineering and scientific opportunities. One of the scientific opportunities is to make observations in the inner magnetosphere at the same time as the twin Van Allen Probes and Cluster. During the Juno flyby, which is on the dusk side at closest approach, the Van Allen Probes' apoapsis is also in the dusk sector. The Cluster orbits favor comparisons on the nightside after Juno's closest approach. Models of the radiation belts suggest that Juno will traverse both the inner and outer belts, albeit at higher latitudes than the low-inclination Van Allen Probes while the Cluster spacecraft are in a rather high inclination orbit. The Waves instrument on Juno utilizes a single electric dipole antenna and a single search coil sensor for measurements of the electric and magnetic components of plasma waves, consequently it will provide wave spectra and brief bursts of waveforms. The Waves instrument on Van Allen Probes, on the other hand makes triaxial electric and magnetic measurements of plasma waves, hence, can determine the propagation characteristics of waves such as the wave-normal angle, Poynting flux, and polarization characteristics of the waves. The Wideband Instrument on Cluster can be configured to capture single axis (electric or magnetic) waveforms at selected times to coincide with Juno and Van Allen Probes burst observations. We will compare observations of whistler-mode emissions and electron cyclotron harmonic emissions in and near the radiation belts from the vantage points of these spacecraft.

  15. Electron densities inferred from plasma wave spectra obtained by the Waves instrument on Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; De Pascuale, S.; Faden, J. B.; Kletzing, C. A.; Hospodarsky, G. B.; Thaller, S.; Wygant, J. R.

    2015-02-01

    The twin Van Allen Probe spacecraft, launched in August 2012, carry identical scientific payloads. The Electric and Magnetic Field Instrument Suite and Integrated Science suite includes a plasma wave instrument (Waves) that measures three magnetic and three electric components of plasma waves in the frequency range of 10 Hz to 12 kHz using triaxial search coils and the Electric Fields and Waves triaxial electric field sensors. The Waves instrument also measures a single electric field component of waves in the frequency range of 10 to 500 kHz. A primary objective of the higher-frequency measurements is the determination of the electron density ne at the spacecraft, primarily inferred from the upper hybrid resonance frequency fuh. Considerable work has gone into developing a process and tools for identifying and digitizing the upper hybrid resonance frequency in order to infer the electron density as an essential parameter for interpreting not only the plasma wave data from the mission but also as input to various magnetospheric models. Good progress has been made in developing algorithms to identify fuh and create a data set of electron densities. However, it is often difficult to interpret the plasma wave spectra during active times to identify fuh and accurately determine ne. In some cases, there is no clear signature of the upper hybrid band, and the low-frequency cutoff of the continuum radiation is used. We describe the expected accuracy of ne and issues in the interpretation of the electrostatic wave spectrum.

  16. Whistler-Mode Waves inside Density Ducts Observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Rosborough, S.; Bengtson, M.; Stein, R. L.; Streltsov, A. V.

    2015-12-01

    The Van Allen Probes satellites launched by NASA in 2012 are currently orbiting in Earth's radiation belts collecting data about electromagnetic waves and charged particles in the near-earth space environment. Whistler-mode waves are naturally occurring right-hand polarized, very-low frequency waves (< 30 kHz), that can efficiently interact with the energetic electrons in the earth's radiation belts magnetosphere and remediate them from the magnetosphere by precipitating these particles into the atmosphere. The important property of the whistler-mode waves is that they can be guided by density inhomogeneities extended along the ambient magnetic field and localized in the direction perpendicular to the field. Such density channels can be formed by the density enhancement or depletion and they are called ducts. The primary goal of our research is to find density duct and whistler waves in the data recorded by the Van Allen Probes satellites in the magnetosphere, and to reproduce these data with numerical simulations of time-dependent, two-dimensional electron MHD model. In this paper, we present results from our analysis of the observations performed by the Van Allen Probes satellites on 15 October 2014. Data from the probes show the electric and magnetic fields and plasma density. In this event whistler-mode waves were observed from 01:42 to 01:54 UT inside the localized density enhancement coincided with the flux of energetic electrons. Short time intervals, high concentrated electron density, and electron flux gradient activity make this event very interesting for the investigation. Numerical simulations of the electron MHD model revels reasonable quantitative agreement between numerical results and satellite observations, suggesting that the electromagnetic disturbances recorded by the Van Allen Probes satellites, are the whistler-mode waves indeed.

  17. In situ observations of EMIC waves in O+ band by the Van Allen Probe A

    NASA Astrophysics Data System (ADS)

    Yu, Xiongdong; Yuan, Zhigang; Wang, Dedong; Li, Haimeng; Huang, Shiyong; Wang, Zhenzhen; Zheng, Qiao; Zhou, Mingxia; Kletzing, C. A.; Wygant, J. R.

    2015-03-01

    Through polarization and spectra analysis of the magnetic field observed by the Van Allen Probe A, we present two typical cases of O+ band electromagnetic ion cyclotron (EMIC) waves in the outer plasmasphere or plasma trough. Although such O+ band EMIC waves are rarely observed, 18 different events of O+ band EMIC waves (16 events in the outer plasmasphere and two events in the plasma trough) are found from September 2012 to August 2014 with observations of the Van Allen Probe A. We find that the preferred region for the occurrence of O+ band EMIC waves is in L = 2-5 and magnetic local time = 03-13, 19-20, which is in accordance with the occurrence region of O+ ion torus. Therefore, our result suggests that the O+ ion torus in the outer plasmasphere during geomagnetic activities should play an important role in the generation of EMIC waves in O+ band.

  18. Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Sarno-Smith, Lois K.; Larsen, Brian A.; Skoug, Ruth M.; Liemohn, Michael W.; Breneman, Aaron; Wygant, John R.; Thomsen, Michelle F.

    2016-02-01

    Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV. It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. We also show noneclipse significant negative charging events on the Van Allen Probes.

  19. Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes

    DOE PAGESBeta

    Sarno-Smith, Lois K.; Larsen, Brian A.; Skoug, Ruth M.; Liemohn, Michael W.; Breneman, Aaron; Wygant, John R.; Thomsen, Michelle F.

    2016-02-27

    Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV.more » It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. Furthermore, we also show noneclipse significant negative charging events on the Van Allen Probes.« less

  20. Pioneer Jupiter orbiter probe mission 1980, probe description

    NASA Technical Reports Server (NTRS)

    Defrees, R. E.

    1974-01-01

    The adaptation of the Saturn-Uranus Atmospheric Entry Probe (SUAEP) to a Jupiter entry probe is summarized. This report is extracted from a comprehensive study of Jovian missions, atmospheric model definitions and probe subsystem alternatives.

  1. Electron densities inferred from plasma wave spectra obtained by the Waves instrument on Van Allen Probes

    PubMed Central

    Kurth, W S; De Pascuale, S; Faden, J B; Kletzing, C A; Hospodarsky, G B; Thaller, S; Wygant, J R

    2015-01-01

    The twin Van Allen Probe spacecraft, launched in August 2012, carry identical scientific payloads. The Electric and Magnetic Field Instrument Suite and Integrated Science suite includes a plasma wave instrument (Waves) that measures three magnetic and three electric components of plasma waves in the frequency range of 10 Hz to 12 kHz using triaxial search coils and the Electric Fields and Waves triaxial electric field sensors. The Waves instrument also measures a single electric field component of waves in the frequency range of 10 to 500 kHz. A primary objective of the higher-frequency measurements is the determination of the electron density ne at the spacecraft, primarily inferred from the upper hybrid resonance frequency fuh. Considerable work has gone into developing a process and tools for identifying and digitizing the upper hybrid resonance frequency in order to infer the electron density as an essential parameter for interpreting not only the plasma wave data from the mission but also as input to various magnetospheric models. Good progress has been made in developing algorithms to identify fuh and create a data set of electron densities. However, it is often difficult to interpret the plasma wave spectra during active times to identify fuh and accurately determine ne. In some cases, there is no clear signature of the upper hybrid band, and the low-frequency cutoff of the continuum radiation is used. We describe the expected accuracy of ne and issues in the interpretation of the electrostatic wave spectrum. PMID:26167442

  2. Climatology of the Earth's inner magnetosphere as observed by the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument on the Van Allen Probes spacecraft.

    NASA Astrophysics Data System (ADS)

    Manweiler, J. W.; Patterson, J. D.; Manweiler, R. M.; Gerrard, A. J.; Mitchell, D. G.; Lanzerotti, L. J.

    2014-12-01

    The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument on the Van Allen Probes spacecraft measures energetic ion and electron particle populations in a species dependent energy range of 10's of KeV up to an MeV. The instrument separates the ion population into component species of protons, helium, and oxygen. This paper presents a climatological survey of RBSPICE measurements over the life of the mission to date. A comparison of spectrographs of the energetic particle populations (e, p, He, and O) is shown against key standard geomagnetic indices. Also shown is a summary of key electron and ion lower energy events based upon a systematic characterization of the type of event. The analyses of these events provide verification of the difference between electron and ion drift orbits and, based upon characterization schemes, show how the different event categories can vary as a function of L and MLT.

  3. The occurrence, spatial distribution, and wave properties of hydrogen-, helium-, and oxygen-band EMIC waves observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Saikin, A.; Zhang, J.; Allen, R. C.; Smith, C. W.; Kistler, L. M.; Spence, H. E.; Torbert, R. B.; Kletzing, C.; Jordanova, V.

    2014-12-01

    Electromagnetic ion cyclotron (EMIC) waves play an important role in the overall dynamics of the Earth's magnetosphere, including the energization and loss of particles. We perform a statistical study of EMIC waves detected by the Van Allen Probes mission to investigate their occurrence, spatial distribution, and properties (e.g., wave power, normal angle, and ellipticity). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard Van Allen Probes are used to identify EMIC wave events from the beginning of the mission (September, 2012) to the present. EMIC waves are examined in hydrogen, helium and oxygen bands. So far, about 280 EMIC wave events have been identified over the three different bands. Preliminary results show that hydrogen-band EMIC waves have been primarily observed in the dusk sector, while helium-band EMIC waves have been observed in all Magnetic Local Times (MLTs). Particularly, the Van Allen Probes provide a better resolution of lower frequencies (0.2-0.9 Hz), within which oxygen-band EMIC waves can occur in the inner magnetosphere. This allows us to obtain better insight into the characteristics of this previously largely unavailable band of EMIC waves, and allows for comparisons amongst EMIC waves in different bands.

  4. Recent Results From The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Kletzing, Craig

    2014-05-01

    The physics of the creation, loss, and transport of radiation belt particles is intimately connected to the electric and magnetic fields which mediate these processes. A large range of field and particle interactions are involved in this physics which are well-measured by the twin Van Allen Probes spacecraft launched in 2012. An overview of recent results from the mission focusing on waves and wave-particle interactions measured by the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation is presented. We show examples of automated density determination and plasmapause identification as derived from the upper hybrid resonance; low frequency ULF pulsations; EMIC waves with electrostatic harmonics and their occurrence statistics; and whistler mode waves including upper and lower band chorus as well as plasmaspheric hiss and its relation to energetic particles.

  5. Outer planet probe missions, designs and science

    NASA Technical Reports Server (NTRS)

    Colin, L.

    1978-01-01

    The similarities and differences of atmosphere entry probe mission designs and sciences appropriate to certain solar system objects, are reviewed. Candidate payloads for Saturn and Titan probes are suggested. Significant supporting research and technology efforts are required to develop mission-peculiar technology for probe exploration of the Saturnian system.

  6. A neural network approach for identifying particle pitch angle distributions in Van Allen Probes data

    NASA Astrophysics Data System (ADS)

    Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.; Rockenbach, M.; Dal Lago, A.; Silveira, M. V. D.; Marchezi, J. P.; Mendes, O.; Gonzalez, W. D.; Baker, D. N.

    2016-04-01

    Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90° peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board the Van Allen Probes, but it is emphasized that our approach can also be used with multiplatform spacecraft data. Our PAD classification results are in reasonably good agreement with those obtained by standard statistical fitting algorithms. The proposed methodology has a potential use for Van Allen belt's monitoring.

  7. Investigating geomagnetic activity dependent sources of 100s of keV electrons in Earth's inner radiation belt using Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Turner, D. L.; O'Brien, T. P., III; Fennell, J. F.; Claudepierre, S. G.; Blake, J. B.; Baker, D. N.; Henderson, M. G.; Reeves, G. D.

    2015-12-01

    By providing an unprecedented level of reliability in particle flux observations at low L-shells, NASA's Van Allen Probes mission has yielded a series of discoveries and unanswered questions concerning the inner electron radiation belt. Two such discoveries are: 1) a sharp cutoff in the energy distribution of electrons at ~900 keV, such that fluxes of electrons with energies greater than ~900 keV are below the detectability threshold of the Van Allen Probes' MagEIS instruments and consistent with upper flux limits of multi-MeV electrons calculated using the Van Allen Probes' REPT instruments, and 2) that impulsive injections of up to several hundred keV electrons may act as an activity-dependent source of electrons in the slot and inner radiation belt. In this presentation, we discuss results from phase space density (PSD) analysis of inner zone electrons. Such analysis, which examines PSD as a function of the three adiabatic invariants, effectively removes adiabatic variations in the particle observations allowing one to better identify source and loss processes ongoing in the system. We demonstrate that impulsive injections do indeed act as a source of inner radiation belt electrons and, when combined with losses in the slot region, can result in peaked radial distributions of electron PSD in the inner zone. We briefly discuss the nature of these low-L injections, which penetrate inside the plasmasphere and display strong energy and species dependencies. By examining such injections throughout the Van Allen Probes era, we also i) determine the occurrence rate of injections as a function of electron energy (and first adiabatic invariant), geomagnetic activity level, and L-shell; ii) estimate the contribution of such injections to the inner belt population; and iii) investigate how such injections disrupt coherent banded flux structures in the inner zone known as "zebra stripes".

  8. Observations and Simulations of Whistler-mode Waves Detected by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Bengtson, M.; Rosborough, S.; Stein, R. L.; Streltsov, A. V.; Matheny, M. M.

    2015-12-01

    In March of 2014, Van Allen Probe A observed several packets of whistler-mode waves while passing through the apogee of an orbit on the dayside magnetosphere. These waves were localized in regions of strong density inhomogeneity. For one observed wave, the wave maximum occurred within the center of the channel formed by a density enhancement. The other two waves were observed on either side of strong density depletion. We first determine the wave characteristics using data from Van Allen Probe A. Then, we use the observations to specify parameters in an electron MHD simulation to model the propagation of whistler-mode waves inside density structures. These observations and simulations demonstrate how whistler-mode waves can become trapped inside density structures, a phenomenon known as ducting. The density ducts serve to guide the whistler-mode waves into the earth's radiation belt while minimizing damping effects. The purpose of this research is to understand the role of density ducts in guiding whistler-mode waves, which will have important applications for remediation of energetic particles from the radiation belt.

  9. 'Trunk-like' ion structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Kistler, L. M.; Spence, H.; Wolf, R.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.; Larsen, B.; Niehof, J. T.; MacDonald, E.; Friedel, R. H.

    2013-12-01

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. In this study, we report 'trunk-like' ion structures observed in situ by the Van Allen Probes on 2 November 2012. The trunk structures are present in heavy ions but not in H+. For the particular event, ion energies in the He+ trunks, located at L = 3.7-2.6, MLT = 8.8-10.3, and MLAT = -2.0-0.03°, vary monotonically from 3.5 to 0.04 keV. It is suggested that the trunk phenomenon is due to a combination of 1) deeper ion injections from storm activity, 2) the longer charge exchange lifetimes of heavy ions than H+, 3) the separation of a narrow layer of ions around the Alfvén layer from other convecting ions, and 4) the trajectory of the Van Allen Probes (i.e., an orbital effect). Both observation analysis and numerical modeling are utilized in the study.

  10. New global loss model of energetic and relativistic electrons based on Van Allen Probes measurements

    NASA Astrophysics Data System (ADS)

    Orlova, Ksenia; Shprits, Yuri; Spasojevic, Maria

    2016-02-01

    The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument on the Van Allen Probes provides a vast quantity of fully resolved wave measurements below L = 5.5, a critical region for radiation belt acceleration and loss. EMFISIS data show that plasmaspheric hiss waves can be observed at frequencies as low as 20 Hz and provide three-component magnetic field measurements that can be directly used for electron scattering calculations. Updated models of hiss properties based on statistical analysis of Van Allen Probes data were recently developed. We use these new models to compute and parameterize the lifetime of electrons as a function of kinetic energy, L shell, Kp index, and magnetic local time. We present a detailed analysis of the electron lifetime sensitivity to the model of the wave intensity and spectral distribution. We also compare the results with previous models of electron loss, which were based on single-component electric field measurements from the sweep frequency receiver on board the CRRES satellite.

  11. EMIC wave spatial and coherence scales as determined from multipoint Van Allen Probe measurements

    NASA Astrophysics Data System (ADS)

    Blum, L. W.; Agapitov, O.; Bonnell, J. W.; Kletzing, C.; Wygant, J.

    2016-05-01

    Electromagnetic ion cyclotron (EMIC) waves can provide a strong source of energetic electron pitch angle scattering. These waves are often quite localized, thus their spatial extent can have a large effect on their overall scattering efficiency. Using measurements from the dual Van Allen Probes, we examine four EMIC wave events observed simultaneously on the two probes at varying spacecraft separations. Correlation of both the wave amplitude and phase observed at both spacecraft is examined to estimate the active region and coherence scales of the waves. We find well-correlated wave amplitude and amplitude modulation across distances spanning hundreds to thousands of kilometers. Phase coherence persisting 30-60 s is observable during close conjunction events but is lost as spacecraft separations exceed ~1 Earth Radii.

  12. Overview of Key Saturn Probe Mission Trades

    NASA Technical Reports Server (NTRS)

    Balint, Tibor S.; Kowalkowski, Theresa; Folkner, Bill

    2007-01-01

    Ongoing studies, performed at NASA/JPL over the past two years in support of NASA's SSE Roadmap activities, proved the feasibility of a NF class Saturn probe mission. I. This proposed mission could also provide a good opportunity for international collaboration with the proposed Cosmic Vision KRONOS mission: a) With ESA contributed probes (descent modules) on a NASA lead mission; b) Early 2017 launch could be a good programmatic option for ESA-CV/NASA-NF. II. A number of mission architectures could be suitable for this mission: a) Probe Relay based architecture with short flight time (approx. 6.3-7 years); b) DTE probe telecom based architecture with long flight time (-11 years), and low probe data rate, but with the probes decoupled from the carrier, allowing for polar trajectories I orbiter. This option may need technology development for telecom; c) Orbiter would likely impact mission cost over flyby, but would provide significantly higher science return. The Saturn probes mission is expected to be identified in NASA's New Frontiers AO. Thus, further studies are recommended to refine the most suitable architecture. International collaboration is started through the KRONOS proposal work; further collaborated studies will follow once KRONOS is selected in October under ESA's Cosmic Vision Program.

  13. The Role of ULF Waves in Ring Current and Radiation Belt Dynamics as Revealed by NASA's Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Claudepierre, S. G.; Mann, I. R.; Takahashi, K.; Toffoletto, F. R.; Wiltberger, M. J.; O'Brien, T. P., III; Fennell, J. F.

    2015-12-01

    NASA's Van Allen Probes have been on orbit since late-August 2012, precessing through all local times over the first two years of the mission, returning high-quality wave and particle observations in the near-Earth space environment. The Probes reveal radiation belt and ring current dynamics with unrivaled accuracy and resolution, providing unambiguous evidence of resonant wave-particle interactions in the inner magnetosphere (e.g., L<7). It is well known that a class of such wave-particle interactions, namely ultra-low frequency (ULF; ~1-10 mHz) wave interactions, contribute to the radial transport of electrons and protons in this region and thus, the large-scale, global morphology of the radiation belts. We focus our investigations on observations of drift-resonance with shock-induced ULF waves, drift-resonance with localized, monochromatic ULF waves, and ULF fluctuations related to nightside particle injections. We also discuss recent advances in the modeling of ULF waves and the challenges that lie ahead.

  14. The occurrence and wave properties of H⁺-, He⁺-, and O⁺-band EMIC waves observed by the Van Allen Probes

    SciTech Connect

    Saikin, A. A.; Zhang, J. -C.; Allen, R. C.; Smith, C. W.; Kistler, L. M.; Spence, H. E.; Torbert, R. B.; Kletzing, C. A.; Jordanova, Vania K.

    2015-09-26

    We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 RE). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the mission operation (8 September 2012 to 30 June 2014). EMIC waves are examined in H⁺-, He⁺-, and O⁺-bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H⁺-band events, 438 He⁺-band events, and 68 O⁺-band events). EMIC wave events are observed between L = 2 – 8, with over 140 EMIC wave events observed below L = 4. The results show that H⁺-band EMIC waves have two peak magnetic local time (MLT) occurrence regions: pre-noon (09:00 < MLT ≤ 12:00) and afternoon (15:00 < MLT ≤ 17:00) sectors. He⁺-band EMIC waves feature an overall stronger dayside occurrence. O⁺-band EMIC waves have one peak region located in the morning sector at lower L shells (L < 4). He⁺-band EMIC waves average the highest wave power overall (>0.1 nT²/Hz), especially in the afternoon sector. Ellipticity observations reveal that linearly polarized EMIC waves dominate in lower L shells.

  15. The occurrence and wave properties of H⁺-, He⁺-, and O⁺-band EMIC waves observed by the Van Allen Probes

    DOE PAGESBeta

    Saikin, A. A.; Zhang, J. -C.; Allen, R. C.; Smith, C. W.; Kistler, L. M.; Spence, H. E.; Torbert, R. B.; Kletzing, C. A.; Jordanova, Vania K.

    2015-09-26

    We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 RE). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the mission operation (8 September 2012 to 30 June 2014). EMIC waves are examined in H⁺-,more » He⁺-, and O⁺-bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H⁺-band events, 438 He⁺-band events, and 68 O⁺-band events). EMIC wave events are observed between L = 2 – 8, with over 140 EMIC wave events observed below L = 4. The results show that H⁺-band EMIC waves have two peak magnetic local time (MLT) occurrence regions: pre-noon (09:00 < MLT ≤ 12:00) and afternoon (15:00 < MLT ≤ 17:00) sectors. He⁺-band EMIC waves feature an overall stronger dayside occurrence. O⁺-band EMIC waves have one peak region located in the morning sector at lower L shells (L < 4). He⁺-band EMIC waves average the highest wave power overall (>0.1 nT²/Hz), especially in the afternoon sector. Ellipticity observations reveal that linearly polarized EMIC waves dominate in lower L shells.« less

  16. Penetration of magnetosonic waves into the plasmasphere observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Xiao, Fuliang; Zhou, Qinghua; He, Yihua; Yang, Chang; Liu, Si; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2015-09-01

    During the small storm on 14-15 April 2014, Van Allen Probe A measured a continuously distinct proton ring distribution and enhanced magnetosonic (MS) waves along its orbit outside the plasmapause. Inside the plasmasphere, strong MS waves were still present but the distinct proton ring distribution was falling steeply with distance. We adopt a sum of subtracted bi-Maxwellian components to model the observed proton ring distribution and simulate the wave trajectory and growth. MS waves at first propagate toward lower L shells outside the plasmasphere, with rapidly increasing path gains related to the continuous proton ring distribution. The waves then gradually cross the plasmapause into the deep plasmasphere, with almost unchanged path gains due to the falling proton ring distribution and higher ambient density. These results present the first report on how MS waves penetrate into the plasmasphere with the aid of the continuous proton ring distributions during weak geomagnetic activities.

  17. Convection Electric Field Observations by THEMIS and the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Califf, S.; Li, X.; Bonnell, J. W.; Wygant, J. R.; Malaspina, D.; Hartinger, M.; Thaller, S. A.

    2013-12-01

    We present direct electric field measurements made by THEMIS and the Van Allen Probes in the inner magnetosphere, focusing on the large-scale, near-DC convection electric field. The convection electric field drives plasma Earthward from the tail into the inner magnetosphere, playing a critical role in forming the ring current. Although it is normally shielded deep inside the magnetosphere, during storm times this large-scale electric field can penetrate to low L values (L < 3), eroding the plasmasphere and also providing a mechanism for ~100 keV electron injection into the slot region and inner radiation belt. The relationship of the convection electric field with the plasmasphere is also important for understanding the dynamic outer radiation belt, as the plasmapause boundary has been strongly correlated with the dynamic variation of the outer radiation belt electrons.

  18. Lobe crossing events observed by the Van Allen Probes as tests of magnetic field line mapping

    NASA Astrophysics Data System (ADS)

    Dixon, P.; MacDonald, E.; Grande, M.; Glocer, A.

    2014-04-01

    In this paper we examine a series of lobe crossing events witnessed by the twin Van Allen Probes spacecraft between 0200 and 0515 on November 14th 2012. The events occurred on the flank between 0400 and 0635 local time and at altitudes between 5.6 and 6.2 RE. During the events Dst was less than 100nT with the IMF being strongly southward (Bz = - 15nT) and eastward (By = 20 nT). Other observations at geosynchronous orbit also show lobe crossings at dawn and dusk flanks. These events provide a chance to examine the magnetic field topology in detail and compare it with models. We will show that the spacecraft were in locations with access to the open field lines by comparison to the CRCM + BATS-RUS models as well as comparing spacecraft encounters with the lobe to the predicted magnetic field topology.

  19. Long-duration exohiss waves outside the plasmasphere: observed by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Su, Z.; Xiao, F.; Zheng, H.; Wang, Y.; He, Z.; Shen, C.; Zhang, M.; Wang, S.; Kletzing, C.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.; Baker, D. N.

    2014-12-01

    We report an exohiss event in the low-density trough region observed by Van Allen Probes on 2 February 2014. These exohiss waves are discovered in the wide MLT distribution [9.1,13.4] and low magnetic latitude, with narrow-band structure and weak intensity compared with plasmaspheric hiss. Using the Continue Waveform Burst Mode data and MAG data on the EMFISIS, we analyze the normal angle, electromagnetic planarity and anti~/parallel-propagating Poynting flux of exohiss wave. The results show indicate that exohiss waves are the result of plasmaspheric hiss leakage into the trough region. The dependence of the proportion of anti~/parallel-propagating Poynting flux on MLT can be explained by Landau damping associated with suprathermal eletrons.

  20. Variability of the Inner Proton Radiation Belt Observed by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Li, X.; Selesnick, R.; Baker, D. N.; Jaynes, A. N.; Kanekal, S. G.; Hudson, M. K.; Kress, B. T.

    2015-12-01

    Inner radiation belt protons with kinetic energy above 10 MeV are known to be highly stable, with a maximum intensity near L = 1.5 that varies little evenon solar-cycle time scales. However, for L = 2 and above, more rapid changes occur: (1) protons are trapped during solar particle events, (2) steady intensity changes near L = 2 may result from radial diffusion, (3) for L > 2 there are rapid losses during magnetic storms, and (4) the losses are replenished by albedo neutron decay. New measurements from Van Allen Probes describe each of the last three processes in detail (the first has not yet been observed). These data provide new constraints on theories of trapped proton dynamics and improved empirical estimates of transport coefficients for radiation belt modeling.

  1. Evidence for Nonlinear VLF Wave Physics from Van Allen Probe Data

    NASA Astrophysics Data System (ADS)

    Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Hospodarsky, G. B.; Kletzing, C.

    2015-12-01

    VLF waves in the whistler mode branch in the Earth's radiation belts play a critical role in both the acceleration and loss of energetic electrons. VLF waves are often observed with magnetic field amplitudes that are a significant fraction of the background magnetic field suggesting that nonlinear effects may be important. We develop new Bayesian time-series analysis tools to investigate magnetic and electric field data from the EMFISIS instrument on board the Van Allen Probes. We also validate the analysis techniques through laboratory experiments. We apply these tools to Chorus waves to show that the picture of a single coherent plane wave is insufficient to explain EMFISIS data and that nonlinear collective wave interactions play an important role in moderating Chorus wave growth. We also apply these techniques to show that nonlinear induced scattering by thermal electrons can play a significant role in controlling the propagation of large amplitude lightning generated whistlers inside the plasmasphere.

  2. Van Allen Probes Multipoint Measurements of the Spatial and Coherence Scales of EMIC Waves

    NASA Astrophysics Data System (ADS)

    Blum, L. W.; Bonnell, J. W.; Agapitov, O. V.; Bortnik, J.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves are able to resonate with MeV electrons and cause precipitation loss of radiation belt electrons. EMIC waves can provide a strong source of electron pitch angle diffusion, but the waves are often quite localized - thus the spatial extents of these waves can have a large effect on their overall scattering efficiency. Using measurements from the Van Allen Probes, we characterize the spatial extents of EMIC wave active regions, and how these depend on local time, radial distance, and driver. As the separation between the spacecraft along the orbital track varies in time, with one spacecraft lapping the other every ~70 days, we can determine the correlation between EMIC wave measurements at varying spacecraft separations. During individual events at close approaches (Jan 17 2013, for example - see attached figure), analysis of the detailed wave properties and coherence is performed. These studies provide important information on parameters relevant for determining resonance of EMIC waves with radiation belt electrons.

  3. Electron dropout echoes induced by interplanetary shock: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Hao, Y. X.; Zong, Q.-G.; Zhou, X.-Z.; Fu, S. Y.; Rankin, R.; Yuan, C.-J.; Lui, A. T. Y.; Spence, H. E.; Blake, J. B.; Baker, D. N.; Reeves, G. D.

    2016-06-01

    On 23 November 2012, a sudden dropout of the relativistic electron flux was observed after an interplanetary shock arrival. The dropout peaks at ˜1 MeV and more than 80% of the electrons disappeared from the drift shell. Van Allen twin Probes observed a sharp electron flux dropout with clear energy dispersion signals. The repeating flux dropout and recovery signatures, or "dropout echoes", constitute a new phenomenon referred to as a "drifting electron dropout" with a limited initial spatial range. The azimuthal range of the dropout is estimated to be on the duskside, from ˜1300 to 0100 LT. We conclude that the shock-induced electron dropout is not caused by the magnetopause shadowing. The dropout and consequent echoes suggest that the radial migration of relativistic electrons is induced by the strong dusk-dawn asymmetric interplanetary shock compression on the magnetosphere.

  4. Pi2 Pulsations Observed by Van Allen Probes: A Case Study

    NASA Astrophysics Data System (ADS)

    Ghamry, E.; Kim, K. H.; Kwon, H. J.; Lee, D. H.; Kletzing, C.; Kurth, W. S.

    2014-12-01

    The plasmaspheric virtual resonance model has been proposed as one of the source mechanisms for low-latitude Pi2 pulsations. Few studies have used simultaneous multipoint observations in space to examine the spatial structure of Pi2 pulsations both inside and outside the plasmasphere. In this study we show multipoint observations for Pi2 pulsations using the Van Allen Probes (RBSP-A and RBSP-B). We focus on the two events that occurred between 1700 and 2000 UT on March 12, 2013, which were simultaneously observed by Van Allen Probes and Bohyun (BOH, L = 1.35) station in South Korea. By using plasma density measurements, we determined that during this time RBSP-A was located outside the plasmasphere and RBSP-B was located inside it. We found that the poloidal, radial (δBx) and compressional (δBz), magnetic field components, and the azimuthal (Ey) electric field component observed by both RBSP-A and RBSP-B have a high correlation with the H component at BOH for both events. The δBx and δBz oscillations at both RBSP-A and RBSP-B are nearly out of phase with ground Pi2. The Ey -H cross phases at RBSP-A outside the plasmapause and RBSP-B inside the plasmapause are nearly in quadrature for the first Pi2 event. These observations indicate that the Pi2 pulsations exist outside the plasmasphere with a radially standing signature which supports the plasmaspheric virtual resonance model.

  5. Generation and effects of EMIC waves observed by the Van Allen Probes on 18 March 2013

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Saikin, A.; Gamayunov, K. V.; Spence, H. E.; Larsen, B.; Geoffrey, R.; Smith, C. W.; Torbert, R. B.; Kurth, W. S.; Kletzing, C.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves play a crucial role in particle dynamics in the Earth's magnetosphere. The free energy for EMIC wave generation is usually provided by the temperature anisotropy of the energetic ring current ions. EMIC waves can in turn cause particle energization and losses through resonant wave-particle interactions. Using measurements from the Van Allen Probes, we perform a case study of EMIC waves and associated plasma conditions observed on 18 March 2013. From 0204 to 0211 UT, the Van Allen Probe-B detected He+-band EMIC wave activity in the post-midnight sector (MLT=4.6-4.9) at very low L-shells (L=2.6-2.9). The event occurred right outside the inward-pushed plasmapause in the early recovery phase of an intense geomagnetic storm - min. Dst = -132 nT at 2100 UT on 17 March 2013. During this event, the fluxes of energetic (> 1 keV), anisotropic O+ dominate both the H+ and He+ fluxes in this energy range. Meanwhile, O+ fluxes at low energies (< 0.1 keV) are low compared to H+ and He+ fluxes in the same energy range. The fluxes of <0.1 keV He+ are clearly enhanced during the wave event, indicating a signature of wave heating. To further confirm the association of the observed plasma features with the EMIC waves, we calculate the electron minimum resonant energy (Emin) and pitch angle diffusion coefficient (Dαα) of the EMIC wave packets by using nominal ion composition, derived total ion density from the frequencies of upper hybrid resonance, and measured ambient and wave magnetic field. EMIC wave growth rates are also calculated to evaluate the role of loss-cone distributed ring current ions in the EMIC wave generation.

  6. Van Allen Probes, NOAA, and Ground Observations of an Intense Pc 1 Wave Event Extending 12 Hours in MLT

    NASA Astrophysics Data System (ADS)

    Engebretson, M. J.; Posch, J. L.; Wygant, J. R.; Kletzing, C.; Lessard, M.; Horne, R. B.; Reeves, G. D.; Gkioulidou, M.; Fennell, J.; Oksavik, K.; Raita, T.

    2014-12-01

    On February 23, 2014 a Pc 1 wave event extending 8 hours in UT and 12 hours in MLT was observed at Halley, Antarctica and Ivalo, Finland in the dawn sector, and by both Van Allen Probes spacecraft from late morning through local noon. The wave activity was stimulated by a gradual 4-hour rise and subsequent sharp increases in solar wind pressure. Intense hydrogen band, linearly polarized Pc 1 wave activity (up to 25 nT p-p) with very similar time variations also appeared for over 4 hours at both Van Allen Probes, located ~8 and ~9 hours east of Halley. Waves appeared when these spacecraft were outside the plasmapause, with densities ~5-20 cm-3. Ten passes of NOAA-POES and METOP satellites near the northern hemisphere footpoint of the Van Allen Probes (over Siberia) show the presence of 30-80 keV subauroral proton precipitation. This is the longest-duration and most intense Pc1 event we have yet observed with the Van Allen Probes. The combination of its duration, intensity, and large local time extent (from before 02 to nearly 14 hours MLT) suggests that it might have a significant effect on the ring current, and possibly even electrons in the outer radiation belt.

  7. Mission Trades to Explore Saturn with Probes

    NASA Astrophysics Data System (ADS)

    Balint, Tibor; Cutts, James; Kolawa, Elizabeth

    To understand the formation of our solar system, the National Research Council in its 2003 Decadal Survey (NRC DS) for Solar System Exploration (SSE), and NASA in its 2006 SSE Roadmap identified mission concepts for the in situ exploration of the giant planets, namely potential probe missions to Jupiter and Saturn. In response, NASA's upcoming 2008 New Frontiers Announcement of Opportunity (AO) is expected to include Saturn among the exploration targets. Our experience with the Galileo probe to Jupiter, the only mission to date to enter a giant planet, highlighted significant technology items, with a special focus on thermal protection system (TPS) performance. Similarly, a medium class, cost capped, probe mission to Saturn is expected to introduce further mission architecture and technology challenges. This paper will provide an overview of typical mission architecture trades for a Saturn multi-probe concept, addressing the impact of trajectory options; operating scenarios through mission phases in support of a not-obvious power system design for the carrier and the probes, using solar panels and batteries; communication options; and key enabling technologies for the probes that could be used on the deceleration and descent modules. While some of the probe technologies could be considered destination specific (e.g,. the highly dense carbon phenolic ablative TPS material for giant planets entries), others could be used at planetary destinations with significant atmospheres (e.g., thermal management and pressure mitigation on future Venus probes), or at exploration targets with extreme environments, as addressed in the 2007 NASA report on extreme environment technologies for planetary exploration.

  8. Empirical modeling of the storm time innermost magnetosphere using Van Allen Probes and THEMIS data: Eastward and banana currents

    NASA Astrophysics Data System (ADS)

    Stephens, G. K.; Sitnov, M. I.; Ukhorskiy, A. Y.; Roelof, E. C.; Tsyganenko, N. A.; Le, G.

    2016-01-01

    The structure of storm time currents in the inner magnetosphere, including its innermost region inside 4RE, is studied for the first time using a modification of the empirical geomagnetic field model TS07D and new data from Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms missions. It is shown that the model, which uses basis-function expansions instead of ad hoc current modules to approximate the magnetic field, consistently improves its resolution and magnetic field reconstruction with the increase of the number of basis functions and resolves the spatial structure and evolution of the innermost eastward current. This includes a connection between the westward ring current flowing largely at and the eastward ring current concentrated at resulting in a vortex current pattern. A similar pattern coined `banana current' was previously inferred from the pressure distributions based on the energetic neutral atom imaging and first-principles ring current simulations. The morphology of the equatorial currents is dependent on storm phase. During the main phase, it is complex, with several asymmetries forming banana currents. Near SYM-H minimum, the banana current is strongest, is localized in the evening-midnight sector, and is more structured compared to the main phase. It then weakens during the recovery phase resulting in the equatorial currents to become mostly azimuthally symmetric.

  9. Deeper and earlier penetrations of oxygen ions than protons into the inner magnetosphere Observed by Van Allen probes.

    NASA Astrophysics Data System (ADS)

    Mitani, K.; Seki, K.; Keika, K.; Lanzerotti, L. J.; Gkioulidou, M.; Mitchell, D. G.; Kletzing, C.

    2015-12-01

    It is observationally known that proton and oxygen ions are main components of the ring current during magnetic storms and that the proton and oxygen ions are considered to have different source and supply mechanisms. However, detailed properties of the ion supply and their dependence on ion species is far from well understood. To characterize the ion supply to the ring current during magnetic storms, we report studies of the properties of energetic proton and oxygen ion phase space densities (PSDs) during the April 23-25, 2013, geomagnetic storm observed by the Van Allen Probes mission. We used energetic ion (~50 - ~600keV protons, ~140 - ~1100keV oxygen) and magnetic field data obtained by the RBSPICE and EMFISIS, respectively, on the Van Allen Probes. We calculated ion PSDs for the specific first adiabatic invariant, mu (0.3 < mu < 12 keV/nT), and ion pitch angles near 90 degrees as a function of L for each spacecraft orbit. The results show that both proton and oxygen ions penetrated directly to L<5 during the main phase of the magnetic storm. Protons with smaller mu values (mu = 0.3 and 0.5 keV/nT) penetrated earlier than those with larger mu values (mu = 1.0 keV/nT). This result appears consistent with the energy dependence of the Alfven layer. The timing of oxygen ion penetration is approximately the same for all mu values (mu = 0.8, 1.0 and 1.2 keV/nT). The observations also show that oxygen ions penetrated more deeply in L and earlier in time than protons for the same mu value (mu = 1.0keV/nT). These results suggest that the source of the transported oxygen ions is located closer to the Earth than the inner edge of protons. The results imply the importance of the contribution from subauroral oxygen ions to the storm-time ring current. We will also discuss the possibility of non-adiabatic acceleration of oxygen ions in the inner magnetosphere.

  10. Pioneer probe mission with orbiter option

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A spacecraft is described which is based on Pioneer 10 and 11, and existing propulsion technology; it can transport and release a probe for entry into Jupiter's atmosphere, and subsequently maneuver to place the spacecraft in orbit about Jupiter. Orbital operations last 3 years and include maneuvers to provide multiple close satellite encounters which allow the orbit to be significantly changed to explore different parts of the magnetosphere. A mission summary, a guide to related documents, and background information about Jupiter are presented along with mission analysis over the complete mission profile. Other topics discussed include the launch, interplanetary flight, probe release and orbit deflection, probe entry, orbit selection, orbit insertion, periapsis raising, spacecraft description, and the effects of Jupiter's radiation belt on both orbiter and the probe.

  11. ACE EPAM and Van Allen Probes RBSPICE measurements of interplanetary oxygen injection to the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Patterson, J. D.; Manweiler, J. W.; Gerrard, A. J.; Lanzerotti, L. J.

    2015-12-01

    On March 17, 2015, a significant oxygen-rich interplanetary event was measure by the Advanced Composition Explorer (ACE) Electron Proton Alpha Monitor (EPAM) instrument. At the same time the Van Allen Probes Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument recorded significant enhancements of oxygen in the inner magnetosphere. We present a detailed analysis of this event utilizing a new method of exploiting the EPAM Pulse Height Analyzer (PHA) data to precisely resolve helium and oxygen spectra within the 0.5 to 5 MeV/nuc range. We also present the flux, partial particle pressures, and pitch angle distributions of the ion measurements from RBSPICE. During this event, both EPAM and RBSPICE measured O:He ratios greater than 10:1. The pitch angle distributions from RBSPICE-B show a strong beam of oxygen at an L ~ 5.8 early on March 17th during orbit. The timing between the observations of the oxygen peak at ACE and the beam observed at RBSPICE-B is consistent with the travel-time required for energetic particle transport from L1 to Earth and access to the magnetosphere. We assert that the oxygen seen by RBSPICE during the initial phase of this event is the result of direct injection from the interplanetary medium of energetic ions. This poster contains the observations and detailed calculations to support this assertion.

  12. Mission Overview for the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Stratton, J. M.; Harvey, R. J.; Heyler, G. A.

    2013-11-01

    Provided here is an overview of Radiation Belt Storm Probes (RBSP) mission design. The driving mission and science requirements are presented, and the unique engineering challenges of operating in Earth's radiation belts are discussed in detail. The implementation of both the space and ground segments are presented, including a discussion of the challenges inherent with operating multiple observatories concurrently and working with a distributed network of science operation centers. An overview of the launch vehicle and the overall mission design will be presented, and the plan for space weather data broadcast will be introduced.

  13. Simultaneous Pi2 observations by the Van Allen Probes inside and outside the plasmasphere

    NASA Astrophysics Data System (ADS)

    Ghamry, E.; Kim, K.-H.; Kwon, H.-J.; Lee, D.-H.; Park, J.-S.; Choi, J.; Hyun, K.; Kurth, W. S.; Kletzing, C.; Wygant, J. R.; Huang, J.

    2015-06-01

    Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid waves detected at Van Allen Probe-A (VAP-A) and Van Allen Probe-B (VAP-B), the plasmapause is identified. At the time of the Pi2 event, VAP-A was outside the plasmasphere near midnight (00:55 MLT and L =˜ 6), while VAP-B was inside the plasmasphere in the postmidnight sector (02:15 MLT and L =˜ 5). VAP-B observed oscillations in the compressional magnetic field component (Bz) and the dawn-to-dusk electric field component (Ey), having high coherence with the BOH Pi2 pulsation in the H component. The H-Bz and H-Ey cross phases at VAP-B inside the plasmasphere were near -180° and -90°, respectively. These phase relationships among Bz, Ey, and H are consistent with a radially standing oscillation of the fundamental mode reported in previous studies. At VAP-A outside the plasmasphere, Bz oscillations were highly correlated with BOH Pi2 pulsations with ˜-180° phase delay, and the H-Ey cross phase is near -90°. From these two-satellite observations, we suggest that the fundamental PVR mode is directly detected by VAP-A and VAP-B.

  14. The role of ring current particle injections: Global simulations and Van Allen Probes observations during 17 March 2013 storm

    NASA Astrophysics Data System (ADS)

    Yu, Yiqun; Jordanova, Vania; Welling, Dan; Larsen, Brian; Claudepierre, Seth G.; Kletzing, Craig

    2014-02-01

    We simulate substorm injections observed by the Van Allen Probes during the 17 March 2013 storm using a self-consistent coupling between the ring current model RAM-SCB and the global MHD model BATS-R-US. This is a significant advancement compared to previous studies that used artificially imposed electromagnetic field pulses to mimic substorm dipolarization and associated inductive electric field. Several substorm dipolarizations and injections are reproduced in the MHD model, in agreement with the timing of shape changes in the AE/AL index. The associated inductive electric field transports plasma sheet plasma to geostationary altitudes, providing the boundary plasma source to the ring current model. It is found that impulsive plasma sheet injections, together with a large-scale convection electric field, are necessary to develop a strong ring current. Comparisons with Van Allen Probes observations show that our model reasonably well captures dispersed electron injections and the global Dst index.

  15. Pulsating aurora observed on the ground and in-situ by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Lessard, M.; Cohen, I. J.; Denton, R. E.; Engebretson, M. J.; Kletzing, C.; Wygant, J. R.; Bounds, S. R.; Smith, C. W.; MacDowall, R. J.; Kurth, W. S.

    2013-12-01

    Early observations and theory related to pulsating aurora suggested that the electrons that drive this aurora originate from the equatorial region of the magnetosphere and that a likely process that can scatter these electrons would involve chorus waves. Recent satellite observations during pulsating auroral events have provided important "firsts", including evidence of strong correlations between pulsating auroral patches and in-situ lower-band chorus (THEMIS), as well as correlations with energetic electron precipitation in the vicinity of geosynchronous orbit (GOES). These results provide important information regarding particle dynamics, leading to a question about how the chorus might be driven. We present observations of the Van Allen Probes in conjunction with a pulsating aurora event, as confirmed by observations on the ground. The in-situ data again show the presence of lower-band chorus. However, magnetic and electric field data also show that the wave bursts coincide with an apparent poloidal field-line resonance, begging the question of whether the resonance might be responsible for driving the VLF waves.

  16. A Neural Network Approach for Identifying Relativistic Electron Pitch Angle Distributions in Van Allen Probes Data

    NASA Astrophysics Data System (ADS)

    Souza, V. M. C. E. S.; Vieira, L.; Alves, L. R.; Da Silva, L. A.; Koga, D.; Sibeck, D. G.; Walsh, B.; Kanekal, S. G.; Silveira, M. D.; Medeiros, C.; Mendes, O., Jr.; Marchezi, J.; Rockenbach, M.; Jauer, P. R.; Gonzalez, W.; Baker, D. N.

    2015-12-01

    A myriad of physical phenomena occur in the inner magnetosphere, in particular at the Earth's radiation belts, which can be a result of the combination of both internal and external processes. However, the connection between physical processes occurring deep within the magnetosphere and external interplanetary drivers it is not yet well understood. In this work we investigate whether a selected set of interplanetary structures affect the local time distribution of three different classes of high energy electron pitch angle distributions (PADs), namely normal, isotropic, and butterfly. We split this work into two parts: initially we focus on the methodology used which employs a Self-Organized Feature Map (SOFM) neural network for identifying different classes of electron PAD shapes in the Van Allen Probes' Relativistic Electron Proton Telescope (REPT) data. The algorithm can categorize the input data into an arbitrary number of classes from which three of them appears the most: normal, isotropic and butterfly. Other classes which are related with these three also emerge and deserve to be addressed in detail in future works. We also discuss the uncertainties of the algorithm. Then, we move to the second part where we describe in details the criteria used for selecting the interplanetary events, and also try to investigate the relation between key parameters characterizing such interplanetary structures and the local time distributions of electron PAD shapes.

  17. Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; Liu, Si; He, Yihua; Wygant, J. R.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.

    2016-05-01

    The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. Here we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ˜300-1500 Hz with the peak wave power density about 10-5 nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1 kHz are more intense and propagate over a broader area than those above 1 kHz, consistent with the observation. The current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions.

  18. "Trunk-like" heavy ion structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhang, J.-C.; Kistler, L. M.; Spence, H. E.; Wolf, R. A.; Reeves, G.; Skoug, R.; Funsten, H.; Larsen, B. A.; Niehof, J. T.; MacDonald, E. A.; Friedel, R.; Ferradas, C. P.; Luo, H.

    2015-10-01

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. We report "trunk-like" ion structures observed by the Van Allen Probes on 2 November 2012. This new type of ion structure looks like an elephant's trunk on an energy-time spectrogram, with the energy of the peak flux decreasing Earthward. The trunks are present in He+ and O+ ions but not in H+. During the event, ion energies in the He+ trunk, located at L = 3.6-2.6, magnetic local time (MLT) = 9.1-10.5, and magnetic latitude (MLAT) = -2.4-0.09°, vary monotonically from 3.5 to 0.04 keV. The values at the two end points of the O+ trunk are energy = 4.5-0.7 keV, L = 3.6-2.5, MLT = 9.1-10.7, and MLAT = -2.4-0.4°. Results from backward ion drift path tracings indicate that the trunks are likely due to (1) a gap in the nightside ion source or (2) greatly enhanced impulsive electric fields associated with elevated geomagnetic activity. Different ion loss lifetimes cause the trunks to differ among ion species.

  19. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    SciTech Connect

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; Fennell, J. F.; Roeder, J. L.; Clemmons, J. H.; Looper, M. D.; Mazur, J. E.; Mulligan, T. M.; Spence, H. E.; Reeves, G. D.; Friedel, R. H. W.; Henderson, M. G.; Larsen, B. A.

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energy channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).

  20. Van Allen Probes observations linking radiation belt electrons to chorus waves during 2014 multiple storms

    NASA Astrophysics Data System (ADS)

    Liu, Si; Xiao, Fuliang; Yang, Chang; He, Yihua; Zhou, Qinghua; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.; Baker, D. N.; Wygant, J. R.

    2015-02-01

    During 18 February to 2 March 2014, the Van Allen Probes encountered multiple geomagnetic storms and simultaneously observed intensified chorus and hiss waves. During this period, there were substantial enhancements in fluxes of energetic (53.8-108.3 keV) and relativistic (2-3.6 MeV) electrons. Chorus waves were excited at locations L = 4-6.2 after the fluxes of energetic were greatly enhanced, with a lower frequency band and wave amplitudes ˜20-100 pT. Strong hiss waves occurred primarily in the main phases or below the location L = 4 in the recovery phases. Relativistic electron fluxes decreased in the main phases due to the adiabatic (e.g., the magnetopause shadowing) or nonadiabatic (hiss-induced scattering) processes. In the recovery phases, relativistic electron fluxes either increased in the presence of enhanced chorus or remained unchanged in the absence of strong chorus or hiss. The observed relativistic electron phase space density peaked around L∗ = 4.5, characteristic of local acceleration. This multiple-storm period reveals a typical picture that chorus waves are excited by the energetic electrons at first and then produce efficient acceleration of relativistic electrons. This further demonstrates that the interplay between both competing mechanisms of chorus-driven acceleration and hiss-driven scattering often occurs in the outer radiation belts.

  1. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    DOE PAGESBeta

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; Fennell, J. F.; Roeder, J. L.; Clemmons, J. H.; Looper, M. D.; Mazur, J. E.; Mulligan, T. M.; Spence, H. E.; et al

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energymore » channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).« less

  2. Quasi-periodic Whistler Mode Waves Detected by the Van Allen Probes Spacecraft

    NASA Astrophysics Data System (ADS)

    Hospodarsky, G. B.; Santolik, O.; Nemec, F.; Kurth, W. S.; Kletzing, C.; Bounds, S. R.; Wygant, J. R.; Bonnell, J. W.

    2014-12-01

    Quasi-periodic (QP) whistler mode electromagnetic emissions have been detected in Earth's magnetosphere by the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) Waves instrument. These emissions typically consist of intervals of enhanced wave power between a few hundred Hz to a few kHz with modulation periods on the order of minutes. These emissions are primarily observed on the dayside and detected between L shells of 3 to 6, though some events are observed down to L shells of ~2. EMFISIS simultaneously measures the vector wave magnetic field and, with the support of the Electric Fields and Waves (EFW) instrument sensors, the vector wave electric field at two locations in Earth's magnetosphere in a continuous survey mode (typically with a 6 second cadence) along with a number of different burst modes to provide high time resolution waveforms (35000 samples per second). These two modes allow a systematic survey of the occurrence of these waves. By measuring all six wave components simultaneously, the wave propagation parameters, such as the wave normal angle and Poynting vector, of these plasma wave emissions are obtained. We will present a statistical survey of the properties of these waves as detected by the Van Allen Probes, examine their occurrence location and use burst data to examine the fine structure of individual events.

  3. The Global Positioning System constellation as a space weather monitor: Comparison of electron measurements with Van Allen Probes data

    NASA Astrophysics Data System (ADS)

    Morley, Steven K.; Sullivan, John P.; Henderson, Michael G.; Blake, J. Bernard; Baker, Daniel N.

    2016-02-01

    Energetic electron observations in Earth's radiation belts are typically sparse, and multipoint studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross calibration into two parts—one that removes any spectral assumptions from the CXD flux calculation and one that compares the energy spectra—we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra, we use a combination of four distributions that together capture a wide range of observed spectral shapes. Our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer and Relativistic Electron-Proton Telescope on Van Allen Probes as a "gold standard," we demonstrate that the CXD instruments are well understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies ≲4 MeV. We present data from 17 CXD-equipped GPS satellites covering the 2015 "St. Patrick's Day" geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting.

  4. The Global Positioning System constellation as a space weather monitor. Comparison of electron measurements with Van Allen Probes data

    DOE PAGESBeta

    Morley, Steven K.; Sullivan, John P.; Henderson, Michael G.; Blake, J. Bernard; Baker, Daniel N.

    2016-02-06

    Energetic electron observations in Earth's radiation belts are typically sparse, and multipoint studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross calibration into two parts—one that removes any spectral assumptions from the CXD flux calculation and one that compares the energy spectra—we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra, wemore » use a combination of four distributions that together capture a wide range of observed spectral shapes. Moreover, our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer and Relativistic Electron-Proton Telescope on Van Allen Probes as a “gold standard,” here we demonstrate that the CXD instruments are well understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies inline image4 MeV. Our team present data from 17 CXD-equipped GPS satellites covering the 2015 “St. Patrick's Day” geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting.« less

  5. Low-harmonic magnetosonic waves observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Posch, J. L.; Engebretson, M. J.; Olson, C. N.; Thaller, S. A.; Breneman, A. W.; Wygant, J. R.; Boardsen, S. A.; Kletzing, C. A.; Smith, C. W.; Reeves, G. D.

    2015-08-01

    Purely compressional electromagnetic waves (fast magnetosonic waves), generated at multiple harmonics of the local proton gyrofrequency, have been observed by various types of satellite instruments (fluxgate and search coil magnetometers and electric field sensors), but most recent studies have used data from search coil sensors, and many have been restricted to high harmonics. We report here on a survey of low-harmonic waves, based on electric and magnetic field data from the Electric Fields and Waves double probe and Electric and Magnetic Field Instrument Suite and Integrated Science fluxgate magnetometer instruments, respectively, on the Van Allen Probes spacecraft during its first full precession through all local times, from 1 October 2012 to 13 July 2014. These waves were observed both inside and outside the plasmapause (PP), at L shells from 2.4 to ~6 (the spacecraft apogee), and in regions with plasma number densities ranging from 10 to >1000 cm-3. Consistent with earlier studies, wave occurrence was sharply peaked near the magnetic equator. Waves appeared at all local times but were more common from noon to dusk, and often occurred within 3 h after substorm injections. Outside the PP occurrence maximized broadly across noon, and inside the PP occurrence maximized in the dusk sector, in an extended plasmasphere. We confirm recent ray-tracing studies showing wave refraction and/or reflection at PP-like boundaries. Comparison with waveform receiver data indicates that in some cases these low-harmonic magnetosonic wave events occurred independently of higher-harmonic waves; this indicates the importance of including this population in future studies of radiation belt dynamics.

  6. Observations of purely compressional waves in the upper ULF band observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Posch, J. L.; Engebretson, M. J.; Johnson, J.; Kim, E. H.; Thaller, S. A.; Wygant, J. R.; Kletzing, C.; Smith, C. W.; Reeves, G. D.

    2014-12-01

    Purely compressional electromagnetic waves, also denoted fast magnetosonic waves, equatorial noise, and ion Bernstein modes, can both heat thermal protons and accelerate electrons up to relativistic energies. These waves have been observed both in the near-equatorial region in the inner magnetosphere and in the plasma sheet boundary layer. Although these waves have been observed by various types of satellite instruments (DC and AC magnetometers and electric field sensors), most recent studies have used data from AC sensors, and many have been restricted to frequencies above ~50 Hz. We report here on a survey of ~200 of these waves, based on DC electric and magnetic field data from the EFW double probe and EMFISIS fluxgate magnetometer instruments, respectively, on the Van Allen Probes spacecraft during its first two years of operation. The high sampling rate of these instruments makes it possible to extend observational studies of the lower frequency population of such waves to lower L shells than any previous study. These waves, often with multiple harmonics of the local proton gyrofrequency, were observed both inside and outside the plasmapause, in regions with plasma number densities ranging from 10 to >1000 cm-3. Wave occurrence was sharply peaked near the magnetic equator and occurred at L shells from below 2 to ~6 (the spacecraft apogee). Waves appeared at all local times but were more common from noon to dusk. Outside the plasmapause, occurrence maximized broadly across noon. Inside the plasmapause, occurrence maximized in the dusk sector, in an extended plasmasphere. Every event occurred in association with a positive gradient in the HOPE omnidirectional proton flux in the range between 2 keV and 10 keV. The Poynting vector, determined for 8 events, was in all cases directed transverse to B, but with variable azimuth, consistent with earlier models and observations.

  7. Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements

    NASA Astrophysics Data System (ADS)

    Zhao, H.; Li, X.; Baker, D. N.; Claudepierre, S. G.; Fennell, J. F.; Blake, J. B.; Larsen, B. A.; Skoug, R. M.; Funsten, H. O.; Friedel, R. H. W.; Reeves, G. D.; Spence, H. E.; Mitchell, D. G.; Lanzerotti, L. J.

    2016-04-01

    Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12% for the moderate storm and ~7% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk.

  8. Outer planet probe navigation. [considering Pioneer space missions

    NASA Technical Reports Server (NTRS)

    Friedman, L.

    1974-01-01

    A series of navigation studies in conjunction with outer planet Pioneer missions are reformed to determine navigation requirements and measurement systems in order to target probes. Some particular cases are established where optical navigation is important and some cases where radio alone navigation is suffucient. Considered are a direct Saturn mission, a Saturn Uranus mission, a Jupiter Uranus mission, and a Titan probe mission.

  9. Location of EMIC Wave Events Relative to the Plasmapause: Van Allen Probes Observations

    NASA Astrophysics Data System (ADS)

    Tetrick, S.; Engebretson, M. J.; Posch, J. L.; Kletzing, C.; Smith, C. W.; Wygant, J. R.; Gkioulidou, M.; Reeves, G. D.; Fennell, J. F.

    2015-12-01

    Many early theoretical studies of electromagnetic ion cyclotron (EMIC) waves generated in Earth's magnetosphere predicted that the equatorial plasmapause (PP) would be a preferred location for their generation. However, several large statistical studies in the past two decades, most notably Fraser and Nguyen [2001], have provided little support for this location. In this study we present a survey of the most intense EMIC waves observed by the EMFISIS fluxgate magnetometer on the Van Allen Probes-A spacecraft (with apogee at 5.9 RE) from its launch through the end of 2014, and have compared their location with simultaneous electron density data obtained by the EFW electric field instrument and ring current ion flux data obtained by the HOPE and RBSPICE instruments. We show distributions of these waves as a function of distance inside or outside the PP as a function of local time sector, frequency band (H+, He+, or both), and timing relative to magnetic storms and substorms. Most EMIC waves in this data set occurred within 1 RE of the PP in all local time sectors, but very few were limited to ± 0.1 RE, and most of these occurred in the 06-12 MLT sector during non-storm conditions. The majority of storm main phase waves in the dusk sector occurred inside the PP. He+ band waves dominated at most local times inside the PP, and H+ band waves were never observed there. Although the presence of elevated fluxes of ring current protons was common to all events, the configuration of lower energy ion populations varied as a function of geomagnetic activity and storm phase.

  10. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

    SciTech Connect

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolik, O.; Clilverd, M.; Rodger, C. J.; Turunen, E.; Tsuchiya, F.

    2015-04-21

    Pulsating auroras show quasi-periodic intensity modulations caused by the precipitation of energetic electrons of the order of tens of keV. It is expected theoretically that not only these electrons but also subrelativistic/relativistic electrons precipitate simultaneously into the ionosphere owing to whistler mode wave-particle interactions. The height-resolved electron density profile was observed with the European Incoherent Scatter (EISCAT) Tromsø VHF radar on 17 November 2012. Electron density enhancements were clearly identified at altitudes >68 km in association with the pulsating aurora, suggesting precipitation of electrons with a broadband energy range from ~10 keV up to at least 200 keV. The riometer and network of subionospheric radio wave observations also showed the energetic electron precipitations during this period. During this period, the footprint of the Van Allen Probe-A satellite was very close to Tromsø and the satellite observed rising tone emissions of the lower band chorus (LBC) waves near the equatorial plane. Considering the observed LBC waves and electrons, we conducted a computer simulation of the wave-particle interactions. This showed simultaneous precipitation of electrons at both tens of keV and a few hundred keV, which is consistent with the energy spectrum estimated by the inversion method using the EISCAT observations. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora, providing the evidence that pulsating auroras are caused by whistler chorus waves. We suggest that scattering by propagating whistler simultaneously causes both the precipitations of subrelativistic electrons and the pulsating aurora.

  11. Externally driven plasmaspheric ULF waves observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazue; Denton, Richard E.; Kurth, William; Kletzing, Craig; Wygant, John; Bonnell, John; Dai, Lei; Min, Kyungguk; Smith, Charles W.; MacDowall, Robert

    2015-01-01

    We analyze data acquired by the Van Allen Probes on 8 November 2012, during a period of extended low geomagnetic activity, to gain new insight into plasmaspheric ultralow frequency (ULF) waves. The waves exhibited strong spectral power in the 5-40 mHz band and included multiharmonic toroidal waves visible up to the eleventh harmonic, unprecedented in the plasmasphere. During this wave activity, the interplanetary magnetic field cone angle was small, suggesting that the waves were driven by broadband compressional ULF waves originating in the foreshock region. This source mechanism is supported by the tailward propagation of the compressional magnetic field perturbations at a phase velocity of a few hundred kilometers per second that is determined by the cross-phase analysis of data from the two spacecraft. We also find that the coherence and phase delay of the azimuthal components of the magnetic field from the two spacecraft strongly depend on the radial separation of the spacecraft and attribute this feature to field line resonance effects. Finally, using the observed toroidal wave frequencies, we estimate the plasma mass density for L = 2.6-5.8. By comparing the mass density with the electron number density that is estimated from the spectrum of plasma waves, we infer that the plasma was dominated by H+ ions and was distributed uniformly along the magnetic field lines. The electron density is higher than the prediction of saturated plasmasphere models, and this "super saturated" plasmasphere and the uniform ion distribution are consistent with the low geomagnetic activity that prevailed.

  12. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    NASA Astrophysics Data System (ADS)

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2015-08-01

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst≈-45) and 14 January 2013 (Dst≈-18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8-6.3, with a lower frequency band 0.1-0.5fce and a peak spectral density ˜10-4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (˜10-300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations to show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ<90° or >90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Moreover, we examine a dayside event during a small storm C on 8 May 2014 (Dst≈-45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.

  13. Characterizing Total Radiation Belt Electron Content Using Van Allen Probes Data

    NASA Astrophysics Data System (ADS)

    Huang, C. L.; Spence, H. E.; Boyd, A. J.; Jordan, A.; Paulson, K. W.; Zhang, J.; Blake, J. B.; Kletzing, C.

    2014-12-01

    The comprehensive particle and wave measurements of the Van Allen Probes enable us to monitor the entire radiation belt near the equator from L-shells of 2.5 to 6. Using the particle measurements, we create an improved, high-level quantity representing the entire outer belt. This quantity, the total radiation belt electron content (TRBEC), is the half-orbit sum of outer belt electrons over the radiation belt energy ranges of importance and all pitch angles using data from RBSP-ECT instrument on board both spacecraft. The goal is to characterize statistically the dynamics of the entire radiation belt by comparing TRBEC with solar wind parameters, magnetospheric waves, and electron seed population. When comparing TRBEC with solar wind velocity, our result shows a triangle-distribution similar to that which Reeves et al. (2011) found using geosynchronous electron flux. We also correlate TRBEC with other solar wind parameters to identify which solar wind conditions effectively enhance or deplete radiation belt electrons. In addition, plasma waves in the inner magnetosphere, via wave-particle interaction, are key elements affecting the dynamics of the radiation belt. Therefore, we compare TRBEC with integrated EMIC and chorus (upper and lower bands) wave power calculated from EMFISIS wave measurements to determine the relative importance between each wave-particle process. Finally, we demonstrate the ~100 keV seed population's characteristics that correspond to the MeV population enhancement. While the gross features of the two populations are similar, the MeV population's dynamics lag behind those of the seed population by 5 to 60 hours, which implies the acceleration or loss processes vary by event.

  14. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

    DOE PAGESBeta

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolik, O.; et al

    2015-04-21

    Pulsating auroras show quasi-periodic intensity modulations caused by the precipitation of energetic electrons of the order of tens of keV. It is expected theoretically that not only these electrons but also subrelativistic/relativistic electrons precipitate simultaneously into the ionosphere owing to whistler mode wave-particle interactions. The height-resolved electron density profile was observed with the European Incoherent Scatter (EISCAT) Tromsø VHF radar on 17 November 2012. Electron density enhancements were clearly identified at altitudes >68 km in association with the pulsating aurora, suggesting precipitation of electrons with a broadband energy range from ~10 keV up to at least 200 keV. The riometermore » and network of subionospheric radio wave observations also showed the energetic electron precipitations during this period. During this period, the footprint of the Van Allen Probe-A satellite was very close to Tromsø and the satellite observed rising tone emissions of the lower band chorus (LBC) waves near the equatorial plane. Considering the observed LBC waves and electrons, we conducted a computer simulation of the wave-particle interactions. This showed simultaneous precipitation of electrons at both tens of keV and a few hundred keV, which is consistent with the energy spectrum estimated by the inversion method using the EISCAT observations. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora, providing the evidence that pulsating auroras are caused by whistler chorus waves. We suggest that scattering by propagating whistler simultaneously causes both the precipitations of subrelativistic electrons and the pulsating aurora.« less

  15. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    SciTech Connect

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations to show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.

  16. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    DOE PAGESBeta

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; et al

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations tomore » show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.« less

  17. The Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Andrews, Stephen F.; ODonnell, James R., Jr.; Ward, David K.; Ericsson, Aprille J.; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe mission is designed to produce a map of the cosmic microwave background radiation over the entire celestial sphere by executing a fast spin and a slow precession of its spin axis about the Sun line to obtain a highly interconnected set of measurements. The spacecraft attitude is sensed and controlled using an Inertial Reference Unit, two Autonomous Star Trackers, a Digital Sun Sensor, twelve Coarse Sun Sensors, three Reaction Wheel Assemblies, and a propulsion system. This paper describes the design of the attitude control system that carries out this mission and presents some early flight experience.

  18. The Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Andrews, Stephen F.; ODonnell, James R., Jr.; Ward, David K.; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe mission is designed to produce a map of the cosmic microwave background radiation over the entire celestial sphere by executing a fast spin and a slow precession of its spin axis about the Sun line to obtain a highly interconnected set of measurements. The spacecraft attitude is sensed and controlled using an inertial reference unit, two star trackers, a digital sun sensor, twelve coarse sun sensors, three reaction wheel assemblies, and a propulsion system. This paper presents an overview of the design of the attitude control system to carry out this mission and presents some early flight experience.

  19. Observational Search for >10 MeV Electrons in the Inner Magnetosphere Using the Van Allen Probes Relativistic Proton Spectrometer

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; Looper, M. D.; O'Brien, T. P., III; Blake, J. B.

    2015-12-01

    Any detection of ultra-relativistic electrons (>10 MeV) trapped in the inner magnetosphere is potentially a sensitive indicator of a unique particle acceleration process or of a unique particle source. The 24 March 1991 shock injection of >15 MeV electrons is a classic example of the former, while the latter includes measurements in low Earth orbit of >100 MeV electrons and positrons from cosmic ray interactions with the atmosphere. In this paper we use new instrumentation on the Van Allen Probes to survey the inner magnetosphere for signatures of ultra-relativistic electrons. The Relativistic Proton Spectrometer, designed primarily for spectroscopy of 60 to 2000 MeV protons in the inner belt, nonetheless is capable of detecting minimum-ionizing electrons in a silicon detector stack. More critical to this survey is the instrument's Cherenkov radiator subsystem whose response to incident electrons ranges from a threshold near 10 MeV and reaches light saturation above 50 MeV. Together with the silicon detector system we are able to explore an energy range that has not been routinely studied in the context of the Earth's magnetosphere. We will report on quiet-time and storm-time signatures in regions of the inner magnetosphere that heretofore have not been explored with an orbit like that of Van Allen Probes. We will also quantitatively compare our electron energy spectra, or flux limits, with other measurements from Van Allen Probes and prior glimpses of high-energy electrons from low Earth orbit.

  20. Van Allen Probes, THEMIS, GOES, and Cluster observations of EMIC waves, ULF pulsations, and an electron flux dropout

    NASA Astrophysics Data System (ADS)

    Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; MacDowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.; Carr, C.; Santolík, O.

    2016-03-01

    We examined an electron flux dropout during the 12-14 November 2012 geomagnetic storm using observations from seven spacecraft: the two Van Allen Probes, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A (P5), Cluster 2, and Geostationary Operational Environmental Satellites (GOES) 13, 14, and 15. The electron fluxes for energies greater than 2.0 MeV observed by GOES 13, 14, and 15 at geosynchronous orbit and by the Van Allen Probes remained at or near instrumental background levels for more than 24 h from 12 to 14 November. For energies of 0.8 MeV, the GOES satellites observed two shorter intervals of reduced electron fluxes. The first interval of reduced 0.8 MeV electron fluxes on 12-13 November was associated with an interplanetary shock and a sudden impulse. Cluster, THEMIS, and GOES observed intense He+ electromagnetic ion cyclotron (EMIC) waves from just inside geosynchronous orbit out to the magnetopause across the dayside to the dusk flank. The second interval of reduced 0.8 MeV electron fluxes on 13-14 November was associated with a solar sector boundary crossing and development of a geomagnetic storm with Dst < -100 nT. At the start of the recovery phase, both the 0.8 and 2.0 MeV electron fluxes finally returned to near prestorm values, possibly in response to strong ultralow frequency (ULF) waves observed by the Van Allen Probes near dawn. A combination of adiabatic effects, losses to the magnetopause, scattering by EMIC waves, and acceleration by ULF waves can explain the observed electron behavior.

  1. Van Allen Probes, THEMIS, GOES, and cluster observations of EMIC waves, ULF pulsations, and an electron flux dropout

    DOE PAGESBeta

    Sigsbee, K.; Kletzing, C. A.; Smith, C. W.; MacDowall, R.; Spence, H.; Reeves, G.; Blake, J. B.; Baker, D. N.; Green, J. C.; Singer, H. J.; et al

    2016-03-04

    We examined an electron flux dropout during the 12–14 November 2012 geomagnetic storm using observations from seven spacecraft: the two Van Allen Probes, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A (P5), Cluster 2, and Geostationary Operational Environmental Satellites (GOES) 13, 14, and 15. The electron fluxes for energies greater than 2.0 MeV observed by GOES 13, 14, and 15 at geosynchronous orbit and by the Van Allen Probes remained at or near instrumental background levels for more than 24 h from 12 to 14 November. For energies of 0.8 MeV, the GOES satellites observed two shorter intervalsmore » of reduced electron fluxes. The first interval of reduced 0.8 MeV electron fluxes on 12–13 November was associated with an interplanetary shock and a sudden impulse. Cluster, THEMIS, and GOES observed intense He+ electromagnetic ion cyclotron (EMIC) waves from just inside geosynchronous orbit out to the magnetopause across the dayside to the dusk flank. The second interval of reduced 0.8 MeV electron fluxes on 13–14 November was associated with a solar sector boundary crossing and development of a geomagnetic storm with Dst <–100 nT. At the start of the recovery phase, both the 0.8 and 2.0 MeV electron fluxes finally returned to near prestorm values, possibly in response to strong ultralow frequency (ULF) waves observed by the Van Allen Probes near dawn. A combination of adiabatic effects, losses to the magnetopause, scattering by EMIC waves, and acceleration by ULF waves can explain the observed electron behavior.« less

  2. Identification of the source of quasiperiodic VLF emissions using ground-based and Van Allen Probes satellite observations

    NASA Astrophysics Data System (ADS)

    Titova, E. E.; Kozelov, B. V.; Demekhov, A. G.; Manninen, J.; Santolik, O.; Kletzing, C. A.; Reeves, G.

    2015-08-01

    We report on simultaneous spacecraft and ground-based observations of quasiperiodic VLF emissions and related energetic-electron dynamics. Quasiperiodic emissions in the frequency range 2-6 kHz were observed during a substorm on 25 January 2013 by Van Allen Probe-A and a ground-based station in the Northern Finland. The spacecraft detected the VLF signals near the geomagnetic equator in the night sector at L = 3.0-4.2 when it was inside the plasmasphere. During the satellite motion toward higher latitudes, the time interval between quasiperiodic elements decreased from 6 min to 3 min. We find one-to-one correspondence between the quasiperiodic elements detected by Van Allen Probe-A and on the ground, which indicates the temporal nature of the observed variation in the time interval between quasiperiodic elements. Multi-component measurements of the wave electric and magnetic fields by the Van Allen Probe-A show that the quasiperiodic emissions were almost circularly right-hand polarized whistler mode waves and had predominantly small (below 30°) wave vector angles with respect to the magnetic field. In the probable source region of these signals (L about 4), we observed synchronous variations of electron distribution function at energies of 10-20 keV and the quasiperiodic elements. In the pause between the quasiperiodic elements pitch angle distribution of these electrons had a maximum near 90°, while they become more isotropic during the development of quasiperiodic elements. The parallel energies of the electrons for which the data suggest direct evidence of the wave-particle interactions is in a reasonable agreement with the estimated cyclotron resonance energy for the observed waves.

  3. Multi-Spacecraft Data Assimilation and Reanalysis During the THEMIS and Van Allen Probes Era

    NASA Astrophysics Data System (ADS)

    Kellerman, A. C.; Shprits, Y.; Kondrashov, D. A.; Podladchikova, T.; Drozdov, A.; Subbotin, D.

    2013-12-01

    consideration of the innovation vector may lead to a new physical understanding of the radiation belt system, which can later be used to improve our model forecasts. In the current study, we explore the radiation belt dynamics of the current era including data from the THEMIS, Van Allen Probes, GPS satellites, Akebono, NOAA and Cluster spacecraft. Intercalibration is performed between spacecraft on an individual energy channel basis, and in invariant coordinates. The global reanalysis allows an unprecedented analysis of the source-acceleration-transport-loss relationship in Earth's radiation belts. This analysis is used to refine our model capabilities, and to prepare the 3-D reanalysis for real-time data. The global 3-D reanalysis is an important step towards full-scale modeling and operational forecasting of this dynamic region of space.

  4. Van Allen Probes observations of dipolarization and its associated O+ flux variations in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Nose, M.; Keika, K.; Kletzing, C.; Smith, C. W.; MacDowall, R. J.; Reeves, G. D.; Spence, H. E.

    2015-12-01

    Recent study employing the MDS-1 satellite reveals that magnetic field dipolarization in the deep inner magnetosphere is not unusual. When the MDS-1 satellite was located at L=3.5-5.0 near the auroral onset longitude (MLT difference of ≤2.5 h), the occurrence probability of local dipolarization was about 16%. Surprisingly, an event was found at L~3.6, far inside the geosynchronous altitude. It was also shown that after the dipolarization, the oxygen ENA flux in the nightside ring current region measured by the IMAGE satellite was predominantly enhanced by a factor of 2-5 and stayed at an enhanced level for more than 1 h, while clear enhancement was scarcely seen in the hydrogen ENA flux. To better understand mechanisms of the selective acceleration of O+ ions during dipolarization, an in-situ measurement of ion fluxes is needed. However, there are few studies investigating H+ and O+ flux variations during dipolarization in the deep inner magnetosphere. In this study we investigate magnetic field dipolarization and its associated ion flux variations in the deep inner magnetosphere, using magnetic field and ion flux data obtained by the Van Allen Probes. From the magnetic field data recorded on the nightside (1800-0600 MLT) in the inner magnetosphere (L=3.0-6.6) in VDH coordinates, we select substorm-related dipolarization events in which the H component increases by more than 20 nT and the absolute value of the V component decreases by more than 8 nT in 5 minutes. About 150 dipolarization events are identified from 1 October 2012 to 30 June 2015. We find that the dipolarization mostly occurs at L=4.5-6.5 in the premidnight sector (2100-0000 MLT). No events are found at L<4.0. Some dipolarization events are accompanied by O+ flux enhancements in the energy range higher than a few keV, which have the pitch angle distribution peaked around 45 or 135 degrees. We also find that low energy O+ ions often appear after dipolarization with an energy dispersion starting from

  5. Relativistic electron response to the combined magnetospheric impact of a coronal mass ejection overlapping with a high-speed stream: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.; Henderson, M. G.; Li, W.; Fennell, J. F.; Zheng, Y.; Richardson, I. G.; Jones, A.; Ali, A. F.; Elkington, S. R.; Jaynes, A.; Li, X.; Blake, J. B.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.

    2015-09-01

    During early November 2013, the magnetosphere experienced concurrent driving by a coronal mass ejection (CME) during an ongoing high-speed stream (HSS) event. The relativistic electron response to these two kinds of drivers, i.e., HSS and CME, is typically different, with the former often leading to a slower buildup of electrons at larger radial distances, while the latter energizing electrons rapidly with flux enhancements occurring closer to the Earth. We present a detailed analysis of the relativistic electron response including radial profiles of phase space density as observed by both Magnetic Electron and Ion Sensor (MagEIS) and Relativistic Electron Proton Telescope instruments on the Van Allen Probes mission. Data from the MagEIS instrument establish the behavior of lower energy (<1 MeV) electrons which span both intermediary and seed populations during electron energization. Measurements characterizing the plasma waves and magnetospheric electric and magnetic fields during this period are obtained by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument on board Van Allen Probes, Search Coil Magnetometer and Flux Gate Magnetometer instruments on board Time History of Events and Macroscale Interactions during Substorms, and the low-altitude Polar-orbiting Operational Environmental Satellites. These observations suggest that during this time period, both radial transport and local in situ processes are involved in the energization of electrons. The energization attributable to radial diffusion is most clearly evident for the lower energy (<1 MeV) electrons, while the effects of in situ energization by interaction of chorus waves are prominent in the higher-energy electrons.

  6. Relativistic Electron Response to the Combined Magnetospheric Impact of a Coronal Mass Ejection Overlapping with a High-Speed Stream: Van Allen Probes Observations

    NASA Technical Reports Server (NTRS)

    Kanekal, S. G.; Baker, D. N.; Henderson, M. G.; Li, W.; Fennell, J. F.; Zheng, Y.; Richardson, I. G.; Jones, A.; Ali, A. F.; Elkington, S. R.; Jaynes, A.; Li, X.; Blake, J. B.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.

    2015-01-01

    During early November 2013, the magnetosphere experienced concurrent driving by a coronal mass ejection (CME) during an ongoing high-speed stream (HSS) event. The relativistic electron response to these two kinds of drivers, i.e., HSS and CME, is typically different, with the former often leading to a slower buildup of electrons at larger radial distances, while the latter energizing electrons rapidly with flux enhancements occurring closer to the Earth. We present a detailed analysis of the relativistic electron response including radial profiles of phase space density as observed by both Magnetic Electron and Ion Sensor (MagEIS) and Relativistic Electron Proton Telescope instruments on the Van Allen Probes mission. Data from the MagEIS instrument establish the behavior of lower energy (<1 MeV) electrons which span both intermediary and seed populations during electron energization. Measurements characterizing the plasma waves and magnetospheric electric and magnetic fields during this period are obtained by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument on board Van Allen Probes, Search Coil Magnetometer and Flux Gate Magnetometer instruments on board Time History of Events and Macroscale Interactions during Substorms, and the low-altitude Polar-orbiting Operational Environmental Satellites. These observations suggest that during this time period, both radial transport and local in situ processes are involved in the energization of electrons. The energization attributable to radial diffusion is most clearly evident for the lower energy (<1 MeV) electrons, while the effects of in situ energization by interaction of chorus waves are prominent in the higher-energy electrons.

  7. The Living with a Star Radiation Belt Storm Probes Mission and Related Missions of Opportunity

    NASA Technical Reports Server (NTRS)

    Sibeck, David G.; Mauk, Barry H.; Grebowsky, Joseph M.; Fox, Nicola J.

    2006-01-01

    This presentation provides an overview of the Living With a Star (LWS) Radiation Belt Storm Probes (RBSP) mission in the context of the broader Geospace program. Missions to Geospace offer an opportunity to observe in situ the fundamental processes that operate throughout the solar system and in particular those that generate hazardous space weather effects in the vicinity of Earth. The recently selected investigations on NASA's LWS program's RBSP will provide the measurements needed to characterize and quantify the processes that supply and remove energetic particles from the Earth's Van Allen radiation belts. Instruments on the RBSP spacecraft will observe charged particles that comprise the Earth's radiation belts over the full energy range from 1 eV to more than 10 MeV (including composition), the plasma waves which energize them, the electric fields which transport them, and the magnetic fields which guide their motion. The two-point measurements by the RBSP spacecraft will enable researchers to discriminate between spatial and temporal effects, and therefore between the various proposed mechanisms for particle acceleration and loss. The measurements taken by the RBSP spacecraft will be used in data modeling projects in order to improve the understanding of these fundamental processes and allow better predictions to be made. NASA's LWS program has also recently selected three teams to study concepts for Missions of Opportunity that will augment the RBSP program, by (1) providing an instrument for a Canadian spacecraft in the Earth's radiation belts, (2) quantifying the flux of particles precipitating into the Earth's atmosphere from the Earth's radiation belts, and (3) remotely sensing both spatial and temporal variations in the Earth's ionosphere and thermosphere.

  8. Global Distribution of Chorus Wave Intensity Directly Measured By Van Allen Probes and Themis and Inferred from Poes Electron Measurements

    NASA Astrophysics Data System (ADS)

    Li, W.; Thorne, R. M.; Ni, B.; Bortnik, J.; Kletzing, C.; Kurth, W. S.; Hospodarsky, G. B.; Angelopoulos, V.; Green, J. C.

    2014-12-01

    Whistler-mode chorus waves play a fundamental role in accelerating seed electrons to highly relativistic energies, as well as causing energetic electron precipitation into the upper atmosphere. Using newly available Van Allen Probes wave data and THEMIS high-resolution wave data, which provide extensive coverage in the entire inner magnetosphere, we construct an empirical global model of chorus wave intensity categorized by various levels of geomagnetic activity. Recently, we have developed a physics-based technique of linking chorus wave intensity and two-directional electron fluxes (30-100 keV) measured at the conjugate low altitudes by POES satellites to show that the inferred chorus wave intensity provides reasonable estimates on the averaged chorus wave intensity. We apply these two different methods, namely (1) the empirical chorus wave model dependent on geomagnetic activity, and (2) the inferred chorus wave intensity from two-directional POES electron measurements, to a few interesting events and evaluate their performance by comparing against in-situ observations of chorus wave intensity from Van Allen Probes and THEMIS. The developed global chorus wave model is critical in quantitatively evaluating the role of chorus waves in radiation belt and ring current electron dynamics.

  9. RAM - C P L Simulations of Electron Transport and Plasma Wave Scattering Using Van Allen Probes Data

    NASA Astrophysics Data System (ADS)

    Jordanova, V.; Zhang, J.; Saikin, A.; Albert, J.; Tu, W.; Chen, Y.; Morley, S.; De Pascuale, S.; Kletzing, C.

    2014-12-01

    The high variability of energetic electron fluxes in the inner magnetosphere remains inadequately explained due to their complex dynamics including competing particle acceleration and loss processes. We study the combined effects from scattering by chorus and EMIC waves and radial transport on ring current and radiation belt dynamics. We use our ring current-atmosphere interactions model that solves the kinetic equation for H+, O+, and He+ ions and electrons and is coupled with a time-dependent 2-D plasmasphere model (RAM-CPL). The plasma boundary conditions are specified from LANL geosynchronous observations. We simulate wave-particle interactions on a global scale as particles drift around the Earth using L and MLT-dependent event-specific chorus and EMIC wave models. The precipitating electron fluxes measured by multiple NOAA satellites are fitted to the equatorial wave measurements made by the EMFISIS instrument on the Van Allen Probes to infer the chorus wave amplitudes on a global scale. The fast dropout of the radiation belts during the October 2012 "double-dip" storm event is investigated and the role of various processes such as outward radial diffusion combined with magnetopause shadowing and enhanced electron precipitation into the atmosphere is evaluated. The simulated cold plasma densities are compared with in situ EMFISIS observations along the Van Allen Probes' orbits showing good agreement.

  10. Ring Current Pressure Estimation withRAM-SCB using Data Assimilation and VanAllen Probe Flux Data

    NASA Astrophysics Data System (ADS)

    Godinez, H. C.; Yu, Y.; Henderson, M. G.; Larsen, B.; Jordanova, V.

    2015-12-01

    Capturing and subsequently modeling the influence of tail plasma injections on the inner magnetosphere is particularly important for understanding the formation and evolution of Earth's ring current. In this study, the ring current distribution is estimated with the Ring Current-Atmosphere Interactions Model with Self-Consistent Magnetic field (RAM-SCB) using, for the first time, data assimilation techniques and particle flux data from the Van Allen Probes. The state of the ring current within the RAM-SCB is corrected via an ensemble based data assimilation technique by using proton flux from one of the Van Allen Probes, to capture the enhancement of ring current following an isolated substorm event on July 18 2013. The results show significant improvement in the estimation of the ring current particle distributions in the RAM-SCB model, leading to better agreement with observations. This newly implemented data assimilation technique in the global modeling of the ring current thus provides a promising tool to better characterize the effect of substorm injections in the near-Earth regions. The work is part of the Space Hazards Induced near Earth by Large, Dynamic Storms (SHIELDS) project in Los Alamos National Laboratory.

  11. Quantifying Energy-Time Dispersion of Relativistic Electron Microbursts to Constrain Their Generation Mechanism: Coordinated Studies Using FIREBIRD, Van Allen Probes, and BARREL

    NASA Astrophysics Data System (ADS)

    Spence, H. E.; Blake, J. B.; Crew, A. B.; Fennell, J. F.; Klumpar, D. M.; Larsen, B.; Millan, R. M.; Miyoshi, Y.; O'Brien, T. P., III; Reeves, G. D.; Smith, S. S.

    2015-12-01

    In this paper, we quantify properties of relativistic electron precipitation at low altitudes in order to constrain the mechanism(s) for microburst loss occurring in Earth's radiation belt. Though studied for decades, the physical mechanism(s) responsible for the loss of radiation belt particles through microburst precipitation to the atmosphere remains uncertain, and, unquantified in a global sense. Accordingly, we appeal to new measurements from the NSF FIREBIRD (Focused Investigation of Relativistic Electron Burst Intensity Range and Dynamics) mission. FIREBIRD comprises two 1.5U CubeSats launched in early 2015 into identical coplanar polar low altitude orbits; a small spring imparted a slow separation between the two spacecraft upon orbit insertion. Over the course of the mission, the orbits of the two identically-instrumented spacecraft slowly evolve, sampling spatial scales of electron precipitation measured simultaneously at separations of 10's to 1000's of kilometers. FIREBIRD provides electron energy spectra from ~250 keV to > 1MeV, with both high spectral resolution (6 to 12 energy channels) and high temporal resolution (principally operated at ~18 millisecond sampling). To do so, FIREBIRD employs two solid-state detectors on each CubeSat, one an uncollimated detector with a large geometric factor (optimized for weak events) and the other a collimated detector (optimized for intense events). While the primary goal of FIREBIRD is to establish the spatial/temporal coherence of microburst precipitation, it also provides the capability of quantifying on each spacecraft the dispersive properties of microbursts. In this work, we report on the energy-time dispersive qualities of individual bursts, which in turn provide a means for testing models and constraining where and how the bursts are generated. To test these models, we use measurements made near the magnetic equator by the Van Allen Probes mission during times when the two FIREBIRD and two Van Allen

  12. Measurements from the Van Allen Probes EFW instrument on the role of electric fields in controlling the structure of the inner magnetosphere and the dynamic of particle energization

    NASA Astrophysics Data System (ADS)

    Wygant, J. R.; Breneman, A. W.; Dai, L.; Thaller, S. A.; Cattell, C. A.; Bonnell, J. W.; Mozer, F.; Agapitov, O. V.; Ergun, R.; Baker, D. N.; Li, X.; Califf, S.; Malaspina, D.; Hudson, M. K.; Millan, R. M.; Halford, A.; Foster, J. C.; Erickson, P. J.; Strangeway, R. J.; Donovan, E.; Kletzing, C.; Kurth, W. S.; Bounds, S. R.; Fennell, J. F.; Reeves, G. D.; Smith, C. W.; Ukhorskiy, A. Y.; Gkioulidou, M.

    2014-12-01

    The Van Allen Probes electric field experiment (EFW) provides measurements in the inner magnetosphere of quasi-static electric fields and high time resolution burst recordings of wave electric and magnetic fields (from the EMFISIS sensors) at rates as high as 16.4 ksamples/s. The EFW instrument also provides estimates of plasma density. We present electric field measurements from the two probes of these electric fields along with magnetic fields and particles to illustrate the role of the electric fields in the erosion of the plasmasphere, the energization of ring current particles, shock acceleration of relativistic particles, and near earth plasma sheet injection of energetic particles. These analysis include comparisons to dc magnetic fields provided by the EMFISIS fluxgate magnetometer and energetic particle measurements (from 10 eV to 20 MeV) provided by HOPE, MagEIS, and REPT instruments in the ECT suite. We will also present a preliminary comparison over the complete duration of the mission between the structure and intensity of the large-scale convection electric field and its interplanetary drivers, including CMEs and SIRs.

  13. Propagation properties of plasmaspheric hiss in the radiation belts: first systematic results from the Van Allen probes

    NASA Astrophysics Data System (ADS)

    Santolik, Ondrej; Hospodarsky, George B.; Kurth, William S.; Averkamp, Terrance F.; Kletzing, Craig A.

    2014-05-01

    The electromagnetic emission of plasmaspheric hiss has been considered to be an important component in the puzzle of the dynamical behavior of Van Allen radiation belts, being held responsible for the slot region between the inner and outer belts. The origin of plasmaspheric hiss is still being debated. A systematic analysis of propagation properties of these waves can provide us with inputs for modeling of radiation belt dynamics. We use new measurements of the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft. Multicomponent data processed by the EMFISIS/Waves instrument allow us to systematically estimate the wave polarization and propagation parameters. The survey data of this instrument are recorded with a nearly 100% coverage. This growing data set allows us to determine probability density functions of characteristics of electromagnetic waves in the typical frequency range of plasmaspheric hiss. This work receives EU support through the FP7-Space grant agreement no 284520 for the MAARBLE collaborative research project.

  14. Plasmatrough exohiss waves observed by Van Allen Probes: Evidence for leakage from plasmasphere and resonant scattering of radiation belt electrons

    NASA Astrophysics Data System (ADS)

    Zhu, Hui; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Shen, Chao; Xian, Tao; Wang, Shui; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.; Baker, D. N.

    2015-02-01

    Exohiss waves are whistler mode hiss observed in the plasmatrough region. We present a case study of exohiss waves and the corresponding background plasma distributions observed by the Van Allen Probes in the dayside low-latitude region. The analysis of wave Poynting fluxes, suprathermal electron fluxes, and cold electron densities supports the scenario that exohiss leaks from the plasmasphere into the plasmatrough. Quasilinear calculations further reveal that exohiss can potentially cause the resonant scattering loss of radiation belt electrons ˜

  15. Innovations on the Solar Probe mission

    NASA Astrophysics Data System (ADS)

    Randolph, James E.; Ayon, Juan A.; Leschly, Kim; Miyake, Robert N.; Tsurutani, Bruce T.

    1998-11-01

    Both instrument and spacecraft innovations are necessary to develop a mission to four solar radii called the Solar Probe. One of the key observable is the solar wind and its characteristics. To observe the solar wind and the entire plasma distribution function near the sun, two different plasma instruments have been incorporated in the current concept. One instrument can take advantage of velocity aberration to observe the solar wind. This plasma instrument uses an innovative pixelated APS-like plasma detector to view this aberrative solar wind and to allow the sampling of a complete plasma distribution function in 10(superscript -2) sec. Another instrument innovation is the nadir viewing plasma spectrometer which will observe solar wind species in the nadir direction that have high velocities and little or no velocity aberration relative to the spacecraft. A high temperature system of electrostatic mirrors with its own solar instruments are another class of instrument innovations on the Solar Probe. Optical observations of the solar disc will be accomplished with filled aperture tubers which will contribute to the reduction of the 3000 suns solar flux to a few suns at the instrument aperture. The tubes will be fabricated form a carbon-carbon material using a process that optimizes its optical properties which reduces its temperature and its mass loss. Its parabolic shape allows the dual function of shield and antenna at the extreme perihelion temperatures of over 2000 K. he high temperature solar arrays will function near perihelion because of thee characteristics: a high temperature photovoltaic material, feathering of the solar arrays to high incidence angles, and the self occultation of the solar arrays near perihelion.

  16. Graphitic heat shields for solar probe missions

    NASA Technical Reports Server (NTRS)

    Lundell, J. H.

    1981-01-01

    The feasibility of using a graphitic heat-shield system on a solar probe going to within 4 solar radii of the center of the sun is investigated. An analysis of graphite vaporization, with commonly used vaporization coefficients, indicates that the maximum mass-loss rate from a conical shield as large as 4 m in diameter can be kept low enough to avoid interference with measurements of the solar environment. In addition to the mass-loss problem, the problem of protecting the payload from the high-temperature (up to 2300 K) primary shield must be solved. An analysis of radiation exchange between concentric disks provides a technique for designing the intermediate shielding. The technique is applied to the design of a system for the Starprobe spacecraft, and it is found that a system with 10 shields and a payload surface temperature of 600 K will have a payload diameter of 2.45 m. Since this is 61% of the 4-m diameter of the primary shield, it is concluded that a graphitic heat-shield system is feasible for the Starprobe mission.

  17. The Radiation Belt Storm Probes

    NASA Video Gallery

    The Radiation Belt Storm Probe mission (RBSP) will explore the Van Allen Radiation Belts in the Earth's magnetosphere. The charge particles in these regions can be hazardous to both spacecraft and ...

  18. Lightning VLF wave propagation from source, through ionosphere to inner magnetosphere using WWLLN and Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Holzworth, R. H.; Brundell, J. B.; Wygant, J. R.; Mozer, F.; Hospodarsky, G. B.; Jacobson, A. R.; Hutchins, M. L.; Bonnell, J. W.; Breneman, A. W.; Kersten, K.

    2013-12-01

    Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. Lightning generated VLF whistler dispersion in the ionosphere has been previously observed both from thunderstorm rockets and low altitude satellites. Previous studies also show a clear match and related attenuation between sferics detected by WWLLN and VLF whistlers observed by C/NOFS satellite. This global study can now be expanded to the magnetosphere using data from the Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)) with high sampling rates for vector electric and magnetic fields, and extended altitude cover from ~600km to ~5 Re above the ground. In our work, we will show the one-to-one coincidence between WWLLN sferics and RBSP VLF whistlers. This talk will explore the relationship between these one to one lightning whistler waves with stimulated emissions such as lower hybrid waves, and possible energy deposition as the large amplitude lightning whistlers propagate into the outer magnetosphere.

  19. ELF/VLF wave propagation at subauroral latitudes: Conjugate observation between the ground and Van Allen Probes A

    NASA Astrophysics Data System (ADS)

    Martinez-Calderon, Claudia; Shiokawa, Kazuo; Miyoshi, Yoshizumi; Keika, Kunihiro; Ozaki, Mitsunori; Schofield, Ian; Connors, Martin; Kletzing, Craig; Hanzelka, Miroslav; Santolik, Ondrej; Kurth, William S.

    2016-06-01

    We report simultaneous observation of ELF/VLF emissions, showing similar spectral and frequency features, between a VLF receiver at Athabasca (ATH), Canada, (L = 4.3) and Van Allen Probes A (Radiation Belt Storm Probes (RBSP) A). Using a statistical database from 1 November 2012 to 31 October 2013, we compared a total of 347 emissions observed on the ground with observations made by RBSP in the magnetosphere. On 25 February 2013, from 12:46 to 13:39 UT in the dawn sector (04-06 magnetic local time (MLT)), we observed a quasiperiodic (QP) emission centered at 4 kHz, and an accompanying short pulse lasting less than a second at 4.8 kHz in the dawn sector (04-06 MLT). RBSP A wave data showed both emissions as right-hand polarized with their Poynting vector earthward to the Northern Hemisphere. Using cross-correlation analysis, we did, for the first time, time delay analysis of a conjugate ELF/VLF event between ground and space, finding +2 to +4 s (ATH first) for the QP and -3 s (RBSP A first) for the pulse. Using backward tracing from ATH to the geomagnetic equator and forward tracing from the equator to RBSP A, based on plasmaspheric density observed by the spacecraft, we validate a possible propagation path for the QP emission which is consistent with the observed time delay.

  20. Near-Earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Wang, Chi; Duan, Suping; He, Zhaohai; Wygant, John R.; Cattell, Cynthia A.; Tao, Xin; Su, Zhenpeng; Kletzing, Craig; Baker, Daniel N.; Li, Xinlin; Malaspina, David; Blake, J. Bernard; Fennell, Joseph; Claudepierre, Seth; Turner, Drew L.; Reeves, Geoffrey D.; Funsten, Herbert O.; Spence, Harlan E.; Angelopoulos, Vassilis; Fruehauff, Dennis; Chen, Lunjin; Thaller, Scott; Breneman, Aaron; Tang, Xiangwei

    2015-08-01

    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeVelectron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L ˜ 5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ˜40 s and a dispersionless injection of electrons up to ˜3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.

  1. Near-earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

    DOE PAGESBeta

    Dai, Lei; Wang, Chi; Duan, Suping; He, Zhaohai; Wygant, John R.; Cattell, Cynthia A.; Tao, Xin; Su, Zhenpeng; Kletzing, Craig; Baker, Daniel N.; et al

    2015-08-10

    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeV electron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L~5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ~40 s and a dispersionless injection of electrons up to ~3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front.more » Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.« less

  2. Near-earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

    SciTech Connect

    Dai, Lei; Wang, Chi; Duan, Suping; He, Zhaohai; Wygant, John R.; Cattell, Cynthia A.; Tao, Xin; Su, Zhenpeng; Kletzing, Craig; Baker, Daniel N.; Li, Xinlin; Malaspina, David; Blake, J. Bernard; Fennell, Joseph; Claudepierre, Seth; Turner, Drew L.; Reeves, Geoffrey D.; Funsten, Herbert O.; Spence, Harlan E.; Angelopoulos, Vassilis; Fruehauff, Dennis; Chen, Lunjin; Thaller, Scott; Breneman, Aaron; Tang, Xiangwei

    2015-08-10

    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeV electron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L~5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ~40 s and a dispersionless injection of electrons up to ~3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.

  3. Scientific Value of a Saturn Atmospheric Probe Mission

    NASA Technical Reports Server (NTRS)

    Simon-Miller, A. A.; Lunine, J. I.; Atreya, S. K.; Spilker, T. R.; Coustenis, A.; Atkinson, D. H.

    2012-01-01

    Atmospheric entry probe mISSions to the giant planets can uniquely discriminate between competing theories of solar system formation and the origin and evolution of the giant planets and their atmospheres. This provides for important comparative studies of the gas and ice giants, and to provide a laboratory for studying the atmospheric chemistries, dynamics, and interiors of all the planets including Earth. The giant planets also represent a valuable link to extrasolar planetary systems. As outlined in the recent Planetary Decadal Survey, a Saturn Probe mission - with a shallow probe - ranks as a high priority for a New Frontiers class mission [1].

  4. Project Helios-A. [mission planning for solar probe

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The Helios-A solar probe which will fly within 28 million miles of the sun is described as a joint American and German project. The spacecraft and instrument designs, planned experiments, and mission are briefly discussed.

  5. Solar Power System Design for the Solar Probe+ Mission

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Schmitz, Paul C.; Kinnison, James; Fraeman, Martin; Roufberg, Lew; Vernon, Steve; Wirzburger, Melissa

    2008-01-01

    Solar Probe+ is an ambitious mission proposed to the solar corona, designed to make a perihelion approach of 9 solar radii from the surface of the sun. The high temperature, high solar flux environment makes this mission a significant challenge for power system design. This paper summarizes the power system conceptual design for the solar probe mission. Power supplies considered included nuclear, solar thermoelectric generation, solar dynamic generation using Stirling engines, and solar photovoltaic generation. The solar probe mission ranges from a starting distance from the sun of 1 AU, to a minimum distance of about 9.5 solar radii, or 0.044 AU, from the center of the sun. During the mission, the solar intensity ranges from one to about 510 times AM0. This requires power systems that can operate over nearly three orders of magnitude of incident intensity.

  6. Simulations of inner magnetosphere dynamics with an expanded RAM-SCB model and comparisons with Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Jordanova, V. K.; Yu, Y.; Niehof, J. T.; Skoug, R. M.; Reeves, G. D.; Kletzing, C. A.; Fennell, J. F.; Spence, H. E.

    2014-04-01

    Simulations from our newly expanded ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB), now valid out to 9 RE, are compared for the first time with Van Allen Probes observations. The expanded model reproduces the storm time ring current buildup due to the increased convection and inflow of plasma from the magnetotail. It matches Magnetic Electron Ion Spectrometer (MagEIS) observations of the trapped high-energy (>50 keV) ion flux; however, it underestimates the low-energy (<10 keV) Helium, Oxygen, Proton, and Electron (HOPE) observations. The dispersed injections of ring current ions observed with the Energetic particle, Composition, and Thermal plasma (ECT) suite at high (>20 keV) energy are better reproduced using a high-resolution convection model. In agreement with Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations, RAM-SCB indicates that the large-scale magnetic field is depressed as close as ˜4.5 RE during even a moderate storm. Regions of electromagnetic ion cyclotron instability are predicted on the duskside from ˜6 to ˜9 RE, indicating that previous studies confined to geosynchronous orbit may have underestimated their scattering effect on the energetic particles.

  7. Large-amplitude electric fields in the inner magnetosphere: Van Allen Probes observations of subauroral polarization streams

    NASA Astrophysics Data System (ADS)

    Califf, S.; Li, X.; Wolf, R. A.; Zhao, H.; Jaynes, A. N.; Wilder, F. D.; Malaspina, D. M.; Redmon, R.

    2016-06-01

    The subauroral polarization stream (SAPS) is an important magnetosphere-ionosphere (MI) coupling phenomenon that impacts a range of particle populations in the inner magnetosphere. SAPS studies often emphasize ionospheric signatures of fast westward flows, but the equatorial magnetosphere is also affected through strong radial electric fields in the dusk sector. This study focuses on a period of steady southward interplanetary magnetic field (IMF) during the 29 June 2013 geomagnetic storm where the Van Allen Probes observe a region of intense electric fields near the plasmapause over multiple consecutive outbound duskside passes. We show that the large-amplitude electric fields near the equatorial plane are consistent with SAPS by investigating the relationship between plasma sheet ion and electron boundaries, associated field-aligned currents, and the spatial location of the electric fields. By incorporating high-inclination DMSP data we demonstrate the spatial and temporal variability of the SAPS region, and we suggest that discrete, earthward propagating injections are driving the observed strong electric fields at low L shells in the equatorial magnetosphere. We also show the relationship between SAPS and plasmasphere erosion, as well as a possible correlation with flux enhancements for 100s keV electrons.

  8. Statistical properties of plasmaspheric hiss derived from Van Allen Probes data and their effects on radiation belt electron dynamics

    NASA Astrophysics Data System (ADS)

    Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Nishimura, Y.

    2015-05-01

    Plasmaspheric hiss is known to play an important role in controlling the overall structure and dynamics of radiation belt electrons inside the plasmasphere. Using newly available Van Allen Probes wave data, which provide excellent coverage in the entire inner magnetosphere, we evaluate the global distribution of the hiss wave frequency spectrum and wave intensity for different levels of substorm activity. Our statistical results show that observed hiss peak frequencies are generally lower than the commonly adopted value (~550 Hz), which was in frequent use, and that the hiss wave power frequently extends below 100 Hz, particularly at larger L shells (> ~3) on the dayside during enhanced levels of substorm activity. We also compare electron pitch angle scattering rates caused by hiss using the new statistical frequency spectrum and the previously adopted Gaussian spectrum and find that the differences are up to a factor of ~5 and are dependent on energy and L shell. Moreover, the new statistical hiss wave frequency spectrum including wave power below 100 Hz leads to increased pitch angle scattering rates by a factor of ~1.5 for electrons above ~100 keV at L~5, although their effect is negligible at L ≤ 3. Consequently, we suggest that the new realistic hiss wave frequency spectrum should be incorporated into future modeling of radiation belt electron dynamics.

  9. Modeling gradual diffusion changes in radiation belt electron phase space density for the March 2013 Van Allen Probes case study

    NASA Astrophysics Data System (ADS)

    Li, Zhao; Hudson, Mary; Jaynes, Allison; Boyd, Alexander; Malaspina, David; Thaller, Scott; Wygant, John; Henderson, Michael

    2014-10-01

    March 2013 provided the first equinoctial period when all of the instruments on the Van Allen Probes spacecraft were fully operational. This interval was characterized by disturbances of outer zone electrons with two time scales of variation, diffusive and rapid dropout and restoration. A radial diffusion model was applied to the monthlong interval to confirm that electron phase space density is well described by radial diffusion for the whole month at low first invariant ≤ 400 MeV/G but peaks in phase space density observed by the Energetic Particle, Composition, and Thermal Plasma (ECT) instrument suite at higher first invariant are not reproduced by radial transport from a source at higher L. The model does well for much of the monthlong interval, capturing three of four enhancements in phase space density which emerge from the outer boundary, while the strong enhancement following dropout on 17-18 March requires local acceleration at higher first invariant (M=1000 MeV/G versus 200 MeV/G) not included in our model. We have incorporated phase space density from ECT measurement at the outer boundary and plasmapause determination from the Electric Field and Waves (EFW) instrument to separate hiss and chorus loss models.

  10. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    PubMed Central

    Fu, Xiangrong; Cowee, Misa M; Friedel, Reinhard H; Funsten, Herbert O; Gary, S Peter; Hospodarsky, George B; Kletzing, Craig; Kurth, William; Larsen, Brian A; Liu, Kaijun; MacDonald, Elizabeth A; Min, Kyungguk; Reeves, Geoffrey D; Skoug, Ruth M; Winske, Dan

    2014-01-01

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr<Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr≃Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ∼Ωe/2 is a natural consequence of the growth of two whistler modes with different properties. PMID:26167433

  11. Intense low-frequency chorus waves observed by Van Allen Probes: Fine structures and potential effect on radiation belt electrons

    NASA Astrophysics Data System (ADS)

    Gao, Zhonglei; Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Shen, Chao; Wang, Shui

    2016-02-01

    Frequency distribution is a vital factor in determining the contribution of whistler mode chorus to radiation belt electron dynamics. Chorus is usually considered to occur in the frequency range 0.1-0.8fce_eq (with the equatorial electron gyrofrequency fce_eq). We here report an event of intense low-frequency chorus with nearly half of wave power distributed below 0.1fce_eq observed by Van Allen Probe A on 27 August 2014. This emission propagated quasi-parallel to the magnetic field and exhibited hiss-like signatures most of the time. The low-frequency chorus can produce the rapid loss of low-energy (˜0.1 MeV) electrons, different from the normal chorus. For high-energy (≥0.5 MeV) electrons, the low-frequency chorus can yield comparable momentum diffusion to that of the normal chorus but much stronger (up to 2 orders of magnitude) pitch angle diffusion near the loss cone.

  12. Charged Particle Behavior in the Growth and Damping Stages of Ultralow Frequency Waves: Theory and Van Allen Probes Observations

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Zhou, X.; Zong, Q.; Chen, X.

    2015-12-01

    Ultralow frequency (ULF) electromagnetic oscillations in the magnetosphere can accelerate electrons via a process called drift resonance. In the conventional drift-resonance theory [Southwood & Kivelson, 1981], a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this may not be always the case in the magnetosphere. The ULF waves should have experienced a growth stage when their energy was taken from external and/or internal sources, and as time progresses the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF waves is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the conventional drift-resonance theory, to study the particle interactions with the waves during the entire wave lifespan. We then predict from the generalized theory the particle signatures for different stages of the waves, which agree very well with Van Allen Probe observations. The more generalized theory, therefore, provides a new understanding of wave-particle interactions and ULF wave evolution in the magnetosphere.

  13. Charged particle behavior in the growth and damping stages of ultralow frequency waves: Theory and Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret G.; Chen, Xing-Ran; Blake, J. Bernard; Wygant, John R.; Kletzing, Craig A.

    2016-04-01

    Ultralow frequency (ULF) electromagnetic waves in Earth's magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift resonance theory, a default assumption is that the wave growth rate is time independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift resonance theory, so that the wave-particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave-particle interactions in the magnetosphere.

  14. A statistical study of whistler waves observed by Van Allen Probes (RBSP) and lightning detected by WWLLN

    NASA Astrophysics Data System (ADS)

    Zheng, Hao; Holzworth, Robert H.; Brundell, James B.; Jacobson, Abram R.; Wygant, John R.; Hospodarsky, George B.; Mozer, Forrest S.; Bonnell, John

    2016-03-01

    Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80% of downloaded waveform data. About 22.9% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1-3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L≥4.

  15. Concepts for a Titan Lake Probe Mission

    NASA Astrophysics Data System (ADS)

    Elliott, John; Waite, Hunter

    2010-05-01

    The lakes of Titan represent an increasingly tantalizing target for future exploration. As Cassini continues to reveal more details the lakes appear to offer a particularly rich reservoir of knowledge that could provide insights to Titan's formation and evolution, as well as an ideal location to explore Titan's potential for pre-biotic chemistry. This talk will discuss the status and preliminary results of a study to evaluate options for missions to investigate Titan's lakes (one of several dozen studies commissioned by the NRC's Planetary Decadal Survey to explore the technical readiness, feasibility and affordability of scientifically promising mission scenarios). In this study a range of potential mission architectures were considered, including in-situ vehicle delivery by a future Titan flagship mission, as well as options for lower cost, standalone missions that could be performed in the next decade. Detailed point designs have been developed for in-situ elements including both floating platforms and submersibles, instrumented to meet varying ranges of science objectives. In this talk we will present an overview of the science objectives of the missions, the mission architecture and surface element trades, and the detailed point designs chosen for more in-depth analysis.

  16. Survey of radiation belt energetic electron pitch angle distributions based on the Van Allen Probes MagEIS measurements

    NASA Astrophysics Data System (ADS)

    Shi, Run; Summers, Danny; Ni, Binbin; Fennell, Joseph F.; Blake, J. Bernard; Spence, Harlan E.; Reeves, Geoffrey D.

    2016-02-01

    A statistical survey of electron pitch angle distributions (PADs) is performed based on the pitch angle-resolved flux observations from the Magnetic Electron Ion Spectrometer (MagEIS) instrument on board the Van Allen Probes during the period from 1 October 2012 to 1 May 2015. By fitting the measured PADs to a sinnα form, where α is the local pitch angle and n is the power law index, we investigate the dependence of PADs on electron kinetic energy, magnetic local time (MLT), the geomagnetic Kp index, and L shell. The difference in electron PADs between the inner and outer belt is distinct. In the outer belt, the common averaged n values are less than 1.5, except for large values of the Kp index and high electron energies. The averaged n values vary considerably with MLT, with a peak in the afternoon sector and an increase with increasing L shell. In the inner belt, the averaged n values are much larger, with a common value greater than 2. The PADs show a slight dependence on MLT, with a weak maximum at noon. A distinct region with steep PADs lies in the outer edge of the inner belt where the electron flux is relatively low. The distance between the inner and outer belt and the intensity of the geomagnetic activity together determine the variation of PADs in the inner belt. Besides being dependent on electron energy, magnetic activity, and L shell, the results show a clear dependence on MLT, with higher n values on the dayside.

  17. Occurrence characteristics of outer zone relativistic electron butterfly distribution: A survey of Van Allen Probes REPT measurements

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Zou, Zhengyang; Li, Xinlin; Bortnik, Jacob; Xie, Lun; Gu, Xudong

    2016-06-01

    Using Van Allen Probes Relativistic Electron Proton Telescope (REPT) pitch angle resolved electron flux data from September 2012 to March 2015, we investigate in detail the global occurrence pattern of equatorial (|λ| ≤ 3°) butterfly distribution of outer zone relativistic electrons and its potential correlation with the solar wind dynamic pressure. The statistical results demonstrate that these butterfly distributions occur with the highest occurrence rate ~ 80% at ~ 20-04 magnetic local time (MLT) and L > ~ 5.5 and with the second peak (> ~ 50%) at ~ 11-15 MLT of lower L shells ~ 4.0. They can also extend to L = 3.5 and to other MLT intervals but with the occurrence rates predominantly < ~25%. It is further shown that outer zone relativistic electron butterfly distributions are likely to peak between 58° and 79° for L = 4.0 and 5.0 and between 37° and 58° for L = 6.0, regardless of the level of solar wind dynamic pressure. Relativistic electron butterfly distributions at L = 4.0 also exhibit a pronounced day-night asymmetry in response to the Pdyn variations. Compared to the significant L shell and MLT dependence of the global occurrence pattern, outer zone relativistic electron butterfly distributions show much less but still discernable sensitivity to Pdyn, geomagnetic activity level, and electron energy, the full understanding of which requires future attempts of detailed simulations that combine and differentiate underlying physical mechanisms of the geomagnetic field asymmetry and scattering by various magnetospheric waves.

  18. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    SciTech Connect

    Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; Funsten, Herbert O.; Gary, S. Peter; Hospodarsky, George B.; Kletzing, Craig; Kurth, William; Larsen, Brian A.; Liu, Kaijun; MacDonald, Elizabeth A.; Reeves, Geoffrey D.; Skoug, Ruth M.; Winske, Dan

    2014-10-22

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ~Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

  19. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    DOE PAGESBeta

    Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; Funsten, Herbert O.; Gary, S. Peter; Hospodarsky, George B.; Kletzing, Craig; Kurth, William; Larsen, Brian A.; Liu, Kaijun; et al

    2014-10-22

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a bandedmore » chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ~Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.« less

  20. O+ ion conic and plasma sheet dynamics observed by Van Allen Probe satellites during the 1 June 2013 magnetic storm

    NASA Astrophysics Data System (ADS)

    Burke, W. J.; Erickson, P. J.; Yang, J.; Foster, J.; Wygant, J.; Reeves, G.; Kletzing, C.

    2016-05-01

    The Van Allen Probe satellites were near apogee in the late evening local time sector during the 1 June 2013 magnetic storm's main phase. About an hour after crossing the ring current's "nose structure" into the plasma sheet, the satellites encountered a quasiperiodic sequence of 0.08-3 keV O+ ions. Pitch angle distributions of this population consistently peaked nearly antiparallel to the local magnetic field. We interpret this population as O+ conics originating in the northern ionosphere. Sequences began as fairly steady state conic fluxes with energies in the ~ 80 to 100 eV range. Over about a half hour buildup phase, O+ energies peaked near 1 keV. During subsequent release phases lasting ~ 20 min, O+ energies returned to low-energy starting points. We argue these observations reflect repeated formations and dissolutions of downward, magnetically aligned electric fields (ɛ||) layers trapping O+ conics between mirror points within heating layers below and electrostatic barriers above. Nearly identical variations were observed at the locations of both satellites during 9 of these 13 conic cycles. Phase differences between cycles were observed at both spacecraft during the remaining events. Most "buildup" to "release" phase transitions coincided with AL index minima. However, in situ magnetometer measurements indicate only weak dipolarizations of tail-like magnetic fields. The lack of field-aligned reflected O+ and tail-like magnetic fields suggest that both ionospheres may be active. However, Southern Hemisphere origin conics cannot be observed since they would be isotropized and accelerated during neutral sheet crossings.

  1. Van Allen Probe Observations: Near-Earth injections of Mev Electrons Associated with Intense Substorm Electric Fields

    NASA Astrophysics Data System (ADS)

    Dai, L.; Wygant, J. R.; Bonnell, J. W.; Cattell, C. A.; Kletzing, C.; Baker, D. N.; Li, X.; Malaspina, D.; Blake, J. B.; Fennell, J.; Claudepierre, S. G.; Takahashi, K.; Funsten, H. O.; Reeves, G. D.; Spence, H. E.; Angelopoulos, V.; Glassmeier, K. H.; Turner, D. L.; Thaller, S. A.; Breneman, A. W.; Kersten, K.; Tang, X.; Tao, X.

    2014-12-01

    With their unique orbit, the Van Allen Probes (RBSP) spacecraft are well suited to investigate near-Earth substorm injections that penetrate into the heart of outer radiation belts. Substorms are generally conceived to inject 10s-100s keV electrons but intense substorm electric fields have been shown capable of injecting ~MeV electrons as well at the geosynchronous altitude. An intriguing question is whether such MeV electron injections can penetrate to lower L shells and directly contribute to the relativistic electron population of the outer radiation belt. In this talk, we present RBSP observations of near-Earth substorm injection of MeV relativistic particles and associated intense dipolarization electric field at L ~5.5. The substorm injection occurred during a moderate storm (DST~-30 to -20) with steady solar wind conditions. RBSP-A observed dispersionless injection of electrons from 10s keV up to 3 MeV in the pre-mid night sector (MLT=22UT). The injection was associated with unusually large (60mV/m) dipolarization electric fields that lasted 1 minute. At about the same time, THEMIS-D observed energy-dispersive injection of electrons at energies as high as at least 720keV at L~6.8 in the pre-dawn sector. Injection of energetic protons (~1MeV) and proton drift echos were observed at RBSP-A as well. RBSP-A observed a broad spectrum of nonlinear electric field structures but no whistler waves at the injection. The properties of the observed dipolarization electric field constrain the acceleration mechanism responsible for the MeV electron injection. We will discuss the implications of these observations on the direct impact of substorms on the outer radiation belt.

  2. Modeling Loss and Rebuilding of the Earth's Outer Zone Electrons and Comparison with Van Allen Probes Measurements

    NASA Astrophysics Data System (ADS)

    Hudson, M. K.; Kress, B. T.; Li, Z.; Paral, J.; Wiltberger, M. J.

    2014-12-01

    Quantifying the competition between radiation belt electron energization due to radial transport and loss to the magnetopause and to the atmosphere is critical to understanding the dynamic changes in outer zone radiation belt electron flux response to solar wind drivers. Plasmasheet electron injection, both due to enhanced convection and substorm dipolarization, provides a source population for generation of whistler mode chorus and seed population for local acceleration. We now have available ~22 months of unprecedented measurements in energy and pitch angle resolution of electrons spanning the energy range from injected plasmasheet to multi-MeV electrons from the twin Van Allen Probes spacecraft in near-equatorial plane elliptical orbits, with apogee at 5.8 Re; and two Balloon Array for Relativistic Radiation Belt Electron Losses (BARREL) campaigns during January-February 2013 and 2014, each establishing a longitudinal array of precipitation measurements extending to relativistic energies via measured Bremsstrahlung x-rays. In addition to this arsenal of data, a set of modeling tools has been developed to examine dynamics of electrons in the magnetosphere. These tools calculate electron trajectories in time-dependent magnetohydrodyanmic (MHD) fields using the Lyon-Fedder-Mobarry global MHD model coupled with the Rice Convection Model to determine the E and B field response to solar wind drivers. With these tools we can follow electron dynamics including response to Ultra Low Frequency (ULF) waves which cause radial transport and energization for inward radial gradient as well as enhanced loss to the magnetopause for outward gradient. These tools have been applied to date to the large equinoctial storms of fall 2012, spring and fall 2013, in addition to moderate storms during BARREL balloon campaigns in both winters 2013 and 2014. Isolated substorm response can clearly be identified for the latter, while plasmasheet injection of electrons during periods of strong

  3. Weak kinetic Alfvén waves turbulence during the 14 November 2012 geomagnetic storm: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Moya, Pablo. S.; Pinto, Víctor A.; Viñas, Adolfo F.; Sibeck, David G.; Kurth, William S.; Hospodarsky, George B.; Wygant, John R.

    2015-07-01

    In the dawn sector, L ˜ 5.5 and MLT ˜ 4-7, from 01:30 to 06:00 UT during the 14 November 2012 geomagnetic storm, both Van Allen Probes observed an alternating sequence of locally quiet and disturbed intervals with two strikingly different power fluctuation levels and magnetic field orientations: either small (˜10-2 nT2) total power with strong GSM Bx and weak By or large (˜10 nT2) total power with weak Bx and strong By and Bz components. During both kinds of intervals the fluctuations occur in the vicinity of the local ion gyrofrequencies (0.01-10 Hz) in the spacecraft frame, propagate oblique to the magnetic field, (θ ˜ 60∘), and have magnetic compressibility C=|δB∥|/|δB⊥|˜1, where δB∥ (δB⊥) are the average amplitudes of the fluctuations parallel (perpendicular) to the mean field. Electric field fluctuations are present whenever the magnetic field is disturbed, and large electric field fluctuations follow the same pattern for quiet and disturbed intervals. Magnetic frequency power spectra at both spacecraft correspond to steep power laws ˜f-α with 4 < α < 5 for f ≲ 2 Hz, and 1.1 < α < 1.7 for f≳ 2 Hz, spectral profiles that are consistent with weak kinetic Alfvén wave (KAW) turbulence. Electric power is larger than magnetic power for all frequencies above 0.1 Hz, and the ratio increases with increasing frequency. Vlasov linear analysis is consistent with the presence of compressive KAW with k⊥ρi≲1, right-handed polarization and positive magnetic helicity, in the plasma frame, considering a multiion plasma. All these results suggest the presence of weak KAW turbulence which dissipates the energy associated with the intermittent sudden changes in the magnetic field during the main phase of the storm.

  4. Solar Probe Plus: Mission design challenges and trades

    NASA Astrophysics Data System (ADS)

    Guo, Yanping

    2010-11-01

    NASA plans to launch the first mission to the Sun, named Solar Probe Plus, as early as 2015, after a comprehensive feasibility study that significantly changed the original Solar Probe mission concept. The original Solar Probe mission concept, based on a Jupiter gravity assist trajectory, was no longer feasible under the new guidelines given to the mission. A complete redesign of the mission was required, which called for developing alternative trajectories that excluded a flyby of Jupiter. Without the very powerful gravity assist from Jupiter it was extremely difficult to get to the Sun, so designing a trajectory to reach the Sun that is technically feasible under the new mission guidelines became a key enabler to this highly challenging mission. Mission design requirements and challenges unique to this mission are reviewed and discussed, including various mission scenarios and six different trajectory designs utilizing various planetary gravity assists that were considered. The V 5GA trajectory design using five Venus gravity assists achieves a perihelion of 11.8 solar radii ( RS) in 3.3 years without any deep space maneuver (DSM). The V 7GA trajectory design reaches a perihelion of 9.5 RS using seven Venus gravity assists in 6.39 years without any DSM. With nine Venus gravity assists, the V 9GA trajectory design shows a solar orbit at inclination as high as 37.9° from the ecliptic plane can be achieved with the time of flight of 5.8 years. Using combined Earth and Venus gravity assists, as close as 9 RS from the Sun can be achieved in less than 10 years of flight time at moderate launch C3. Ultimately the V 7GA trajectory was chosen as the new baseline mission trajectory. Its design allowing for science investigation right after launch and continuing for nearly 7 years is unprecedented for interplanetary missions. The redesigned Solar Probe Plus mission is not only feasible under the new guidelines but also significantly outperforms the original mission concept

  5. Saturn Uranus atmospheric entry probe mission spacecraft system definition study

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The modifications required of the Pioneer F/G spacecraft design for it to deliver an atmospheric entry probe to the planets Saturn and Uranus are investigated. It is concluded that it is feasible to conduct such a mission within the constraints and interfaces defined. The spacecraft required to perform the mission is derived from the Pioneer F/G design, and the modifications required are generally routinely conceived and executed. The entry probe is necessarily a new design, although it draws on the technology of past, present, and imminent programs of planetary atmospheric investigations.

  6. Scientific Rationale of a Saturn Probe Mission

    NASA Astrophysics Data System (ADS)

    Mousis, Olivier; Fletcher, Leigh N.; Lebreton, Jean-Pierre; Wurz, Peter; Cavalié, Thibault; Coustenis, Athena; Atkinson, Dave H.; Atreya, Sushil; Gautier, Daniel; Guillot, Tristan; Lunine, Jonathan I.; Marty, Bernard; Morse, Andrew D.; Rey, Kim R.; Simon-Miller, Amy; Spilker, Thomas R.; Waite, Jack Hunter

    2014-05-01

    Remote sensing observations meet some limitations when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the unicity of in situ probe measurements is illustrated by the exploration of Jupiter, where key measurements such as noble gases abundances and the precise measurement of the helium mixing ratio have only been made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by future in situ exploration of Saturn. Planet formation: To understand the formation of giant planets and the origin of our Solar System, statistical data obtained from the observation of exoplanetary systems must be supplemented by direct measurements of the composition of the planets in our solar system. A giant planet's bulk composition depends on the timing and location of planet formation, subsequent migration and the delivery mechanisms for the heavier elements. By measuring a giant planet's chemical inventory, and contrasting these with measurements of (i) other giant planets, (ii) primitive materials found in small bodies, and (iii) the composition of our parent star and the local interstellar medium, much can be revealed about the conditions at work during the formation of our planetary system [1]. To date, the Galileo probe at Jupiter (1995) remains our only data point for interpreting the bulk composi-tion of the giant planets. Galileo found that Jupiter exhibited an enrichment in C, N, S, Ar, Kr and Xe compared to the solar photospheric abundances, with some notable exceptions - water was found depleted, possibly due to meteorological processes at the probe entry site; and neon was also found depleted, possibly due to rain-out to deeper levels [2]. Explaining the high abundance of noble gases requires either condensing these elements directly at low-temperature in the form of amorphous ices [3], trapping them as clathrates [4-7] or photoevaporating the

  7. Scientific Rationale of a Saturn Probe Mission

    NASA Astrophysics Data System (ADS)

    Mousis, Olivier; Fletcher, Leigh N.; Lebreton, Jean-Pierre; Wurz, Peter; Cavalié, Thibault; Coustenis, Athena; Atkinson, Dave H.; Atreya, Sushil; Gautier, Daniel; Guillot, Tristan; Lunine, Jonathan I.; Marty, Bernard; Morse, Andrew D.; Rey, Kim R.; Simon-Miller, Amy; Spilker, Thomas R.; Waite, Jack Hunter

    2014-05-01

    Remote sensing observations meet some limitations when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the unicity of in situ probe measurements is illustrated by the exploration of Jupiter, where key measurements such as noble gases abundances and the precise measurement of the helium mixing ratio have only been made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by future in situ exploration of Saturn. Planet formation: To understand the formation of giant planets and the origin of our Solar System, statistical data obtained from the observation of exoplanetary systems must be supplemented by direct measurements of the composition of the planets in our solar system. A giant planet's bulk composition depends on the timing and location of planet formation, subsequent migration and the delivery mechanisms for the heavier elements. By measuring a giant planet's chemical inventory, and contrasting these with measurements of (i) other giant planets, (ii) primitive materials found in small bodies, and (iii) the composition of our parent star and the local interstellar medium, much can be revealed about the conditions at work during the formation of our planetary system [1]. To date, the Galileo probe at Jupiter (1995) remains our only data point for interpreting the bulk composi-tion of the giant planets. Galileo found that Jupiter exhibited an enrichment in C, N, S, Ar, Kr and Xe compared to the solar photospheric abundances, with some notable exceptions - water was found depleted, possibly due to meteorological processes at the probe entry site; and neon was also found depleted, possibly due to rain-out to deeper levels [2]. Explaining the high abundance of noble gases requires either condensing these elements directly at low-temperature in the form of amorphous ices [3], trapping them as clathrates [4-7] or photoevaporating the

  8. Van Allen probes, NOAA, GOES, and ground observations of an intense EMIC wave event extending over 12 h in magnetic local time

    NASA Astrophysics Data System (ADS)

    Engebretson, M. J.; Posch, J. L.; Wygant, J. R.; Kletzing, C. A.; Lessard, M. R.; Huang, C.-L.; Spence, H. E.; Smith, C. W.; Singer, H. J.; Omura, Y.; Horne, R. B.; Reeves, G. D.; Baker, D. N.; Gkioulidou, M.; Oksavik, K.; Mann, I. R.; Raita, T.; Shiokawa, K.

    2015-07-01

    Although most studies of the effects of electromagnetic ion cyclotron (EMIC) waves on Earth's outer radiation belt have focused on events in the afternoon sector in the outer plasmasphere or plume region, strong magnetospheric compressions provide an additional stimulus for EMIC wave generation across a large range of local times and L shells. We present here observations of the effects of a wave event on 23 February 2014 that extended over 8 h in UT and over 12 h in local time, stimulated by a gradual 4 h rise and subsequent sharp increases in solar wind pressure. Large-amplitude linearly polarized hydrogen band EMIC waves (up to 25 nT p-p) appeared for over 4 h at both Van Allen Probes, from late morning through local noon, when these spacecraft were outside the plasmapause, with densities ~5-20 cm-3. Waves were also observed by ground-based induction magnetometers in Antarctica (near dawn), Finland (near local noon), Russia (in the afternoon), and in Canada (from dusk to midnight). Ten passes of NOAA-POES and METOP satellites near the northern foot point of the Van Allen Probes observed 30-80 keV subauroral proton precipitation, often over extended L shell ranges; other passes identified a narrow L shell region of precipitation over Canada. Observations of relativistic electrons by the Van Allen Probes showed that the fluxes of more field-aligned and more energetic radiation belt electrons were reduced in response to both the emission over Canada and the more spatially extended emission associated with the compression, confirming the effectiveness of EMIC-induced loss processes for this event.

  9. Mission to Jupiter. [Pioneer 10 and 11 space probes

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The Pioneer 10 and Pioneer 11 space probes and their missions to Jupiter are discussed along with the experiments and investigations which will be conducted onboard. Jupiter's atmosphere, its magnetic fields, radiation belts, the spacecraft instruments, and the Jovian system will be investigated. Educational study projects are also included.

  10. Auroral Spatial Structures Probe Sub-Orbital Mission Preliminary Results

    NASA Astrophysics Data System (ADS)

    Pratt, J.; Swenson, C.; Martineau, R. J.; Fish, C. S.; Conde, M.; Hampton, D.; Crowley, G.

    2015-12-01

    The NASA Auroral Spatial Structures Probe, 49.002, was launched January 28, 2015 from the Poker Flat Research Range into active aurora over the northern coast of Alaska. The primary objective of this mission was to determine the contribution of small spatial and temporal scale fluctuations of the electric fields to the larger-scale energy deposition processes associated with the aurora. The Auroral Spatial Structures Probe Sub-Orbital Mission consisted of a formation of 7 spacecraft (a main payload with 6 deployable sub-payloads) designed for multiple temporally spaced co-located measurements of electric and magnetic fields in the earth's ionosphere. The mission was able to make observations at a short time scale and small spatial scale convergence that is unobservable by either satellite or ground-based observations. The payloads included magnetometers, electric field double probes, and Langmuir probes as well as a sweeping impedance probe on the main payload. We present here preliminary results from the measurements taken that hint at the underlying spatial structure of the currents and energy deposition in the aurora. The Poynting flux derived from the observations is shown and implications are discussed in terms of the contribution of small spatial scale, rapid temporal scale fluctuations in the currents that deposit energy in the auroral region. Funding provided by NASA Grants NNX11AE23G and NNX13AN20A.

  11. Analysis of plasmaspheric hiss wave amplitudes inferred from low-altitude POES electron data: Validation with conjunctive Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Soria-Santacruz, M.; Li, W.; Thorne, R. M.; Ma, Q.; Bortnik, J.; Ni, B.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.

    2015-10-01

    Plasmaspheric hiss plays an important role in controlling the overall structure and dynamics of the Earth's radiation belts. The interaction of plasmaspheric hiss with radiation belt electrons is commonly evaluated using diffusion codes, which rely on statistical models of wave observations that may not accurately reproduce the instantaneous global wave distribution or the limited in situ satellite wave measurements. This paper evaluates the performance and limitations of a novel technique capable of inferring wave amplitudes from low-altitude electron flux observations from the Polar Orbiting Environmental Satellites (POES), which provide extensive coverage in shell and magnetic local time (MLT). We found that, within its limitations, this technique could potentially be used to build a dynamic global model of the plasmaspheric hiss wave intensity. The technique is validated by analyzing the conjunctions between the POES spacecraft and the Van Allen Probes from September 2012 to June 2014. The technique performs well for moderate-to-strong hiss activity (≥30 pT) with sufficiently high electron fluxes. The main source of these limitations is the number of counts of energetic electrons measured by the POES spacecraft capable of resonating with hiss waves. For moderate-to-strong hiss events, the results show that the wave amplitudes from the EMFISIS instruments on board the Van Allen Probes are well reproduced by the POES technique, which provides more consistent estimates than the parameterized statistical hiss wave model based on CRRES data.

  12. Using ACE Observations of Interplanetary Particles and Magnetic Fields as Possible Contributors to Variations Observed at Van Allen Probes during Major events in 2013

    NASA Astrophysics Data System (ADS)

    Armstrong, T. P.; Manweiler, J. W.; Gerrard, A. J.; Gkioulidou, M.; Lanzerotti, L. J.; Patterson, J. D.

    2013-12-01

    Observations from ACE EPAM including energy spectra of protons, helium, and oxygen will be prepared for coordinated use in estimating the direct and indirect access of energetic particles to inner and outer geomagnetic trapping zones. Complete temporal coverage from ACE at 12 seconds, 5 minutes, 17 minutes, hourly and daily cadences will be used to catalog interplanetary events arriving at Earth including interplanetary magnetic field sector boundaries, interplanetary shocks, and interplanetary coronal mass ejections, ICMEs. The first 6 months of 2013 have included both highly disturbed times, March 17 and May 22, and extended quiet periods of little or no variations. Among the specific questions that ACE and Van Allen Probes coordinated observations may aid in resolving are: 1. How much, if any, direct capture of interplanetary energetic particles occurs and what conditions account for it? 2. How much influence do interplanetary field and particle variations have on energization and/or loss of geomagnetically trapped populations? The poster will also present important links and describe methods and important details of access to numerically expressed ACE EPAM and Van Allen Probes RBSPICE observations that can be flexibly and easily accessed via the internet for student and senior researcher use.

  13. The dependence on geomagnetic conditions and solar wind dynamic pressure of the spatial distributions of EMIC waves observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Saikin, A. A.; Zhang, J.-C.; Smith, C. W.; Spence, H. E.; Torbert, R. B.; Kletzing, C. A.

    2016-05-01

    A statistical examination on the spatial distributions of electromagnetic ion cyclotron (EMIC) waves observed by the Van Allen Probes against varying levels of geomagnetic activity (i.e., AE and SYM-H) and dynamic pressure has been performed. Measurements taken by the Electric and Magnetic Field Instrument Suite and Integrated Science for the first full magnetic local time (MLT) precession of the Van Allen Probes (September 2012-June 2014) are used to identify over 700 EMIC wave events. Spatial distributions of EMIC waves are found to vary depending on the level of geomagnetic activity and solar wind dynamic pressure. EMIC wave events were observed under quiet (AE ≤ 100 nT, 325 wave events), moderate (100 nT < AE ≤ 300 nT, 218 wave events), and disturbed (AE > 300 nT, 228 wave events) geomagnetic conditions and are primarily observed in the prenoon sector (~800 < MLT ≤ ~1100) at L ≈ 5.5 during quiet activity times. As AE increases to disturbed levels, the peak occurrence rates shift to the afternoon sector (1200 < MLT ≤ 1800) between L = 4 and L = 6. A majority of EMIC wave events (~56%) were observed during nonstorm times (defined by SYM-H). Consistent with the quiet AE levels, nonstorm EMIC waves are observed in the prenoon sector. EMIC waves observed through the duration of a geomagnetic storm are primarily located in the afternoon sector. High solar wind pressure (Pdyn > 3 nPa) correlates to mostly afternoon EMIC wave observations.

  14. Possible concepts for an in situ Saturn probe mission

    NASA Astrophysics Data System (ADS)

    Coustenis, Athena; Lebreton, Jean-Pierre; Mousis, Olivier; Atkinson, David H.; Lunine, Jonathan I.; Reh, Kim R.; Fletcher, Leigh N.; Simon-Miller, Amy A.; Atreya, Sushil; Brinckerhoff, William B.; Cavalie, Thibault; Colaprete, Anthony; Gautier, Daniel; Guillot, Tristan; Mahaffy, Paul R.; Marty, Bernard; Morse, Andy; Sims, Jon; Spilker, Tom; Spilker, Linda

    2014-05-01

    In situ exploration of Saturn's atmosphere would bring insights in two broad themes: the formation history of our solar system and the processes at play in planetary atmospheres. The science case for in situ measurements at Saturn are developed in [1] and two companion abstracts (see Mousis et al., and Atkinson et al.). They are summarized here. Measurements of Saturn's bulk chemical and isotopic composition would place important constraints on the volatile reservoirs in the protosolar nebula and hence on the formation mechanisms. An in situ probe, penetrating from the upper atmosphere (μbar level) into the convective weather layer to a minimum depth of 10 bar, would also contribute to our knowledge of Saturn's atmospheric structure, dynamics, composition, chemistry and cloud-forming processes. Different mission architectures are envisaged, all based on an entry probe that would descend through Saturn's stratosphere and troposphere under parachute down to a minimum of 10 bars [1]. Future studies will focus on the trade-offs between science return and the added design complexity of a probe that could operate at pressures larger than 10 bars. Accelerometry measurements may also be performed during the entry phase in the higher part of the stratosphere prior to starting measurements under parachute. A carrier system would be required to deliver the probe along its interplanetary trajectory to the desired atmospheric entry point at Saturn. The entry site would be carefully selected. Three possible mission configurations are currently under study (with different risk/cost trades): • Configuration 1: Probe + Carrier. After probe delivery, the carrier would follow its path and be destroyed during atmospheric entry, but could perform pre-entry science. The carrier would not be used as a radio relay, but the probe would transmit its data to the ground system via a direct-to-Earth (DTE) RF link; • Configuration 2: Probe + Carrier/Relay. The probe would detach from the

  15. Van Allen Probes observations of intense parallel Poynting flux associated with magnetic dipolarization, conjugate discrete auroral arcs, and energetic particle injection

    NASA Astrophysics Data System (ADS)

    Wygant, J. R.; Thaller, S. A.; Breneman, A. W.; Tian, S.; Cattell, C. A.; Chaston, C. C.; Mozer, F.; Bonnell, J. W.; Kistler, L. M.; Mouikis, C.; Hudson, M. K.; Claudepierre, S. G.; Fennell, J. F.; Reeves, G. D.; Baker, D. N.; Donovan, E.; Spanswick, E.; Kletzing, C.

    2015-12-01

    We present measurements from the Van Allen Probes, in the near Earth tail, at the outer boundary of the plasma sheet, of a magnetic dipolarization/injection event characterized by unusually strong earthward poynting flux flowing along magnetic field lines with amplitudes of 200 mW/m2 lasting ~ 1 minute. The Poynting flux was conjugate to a 30 km wide discrete auroral arc observed by the THEMIS auroral array. The observations were obtained at 5.8 Re in the pre-midnight sector during the main phase of a geomagnetic storm on 5/01/2013. This brief interval transferred more electromagnetic energy (at the spacecraft position) than that transferred during entire remainder of the main phase of the storm. The parallel Poynting flux coincided with a local section of the "cross tail current sheet" which generated the dipolarization signature. The latitudinal width of the arc, mapped along magnetic field lines, provides an estimate of the spatial scale of the Poynting flux, the electric fields, and the current sheets (parallel and perpendicular). It is estimated that the latitudinal width of the Poynting flux "sheet" was ~600 km or ~1-2 H+ inertial lengths. An estimate of the ∫E·dl across the current sheet along the direction normal to the plasma sheet is ~20-40 kilovolts. The "normal" to the plasma sheet component of the electric field (~70 mV/m) strongly dominated the azimuthal component(which is reponsible for drift energetization). The dipolarization event resulted in the local dispersion-less injection of electrons between 50 keV and ~2 MeV at the Van Allen Probe position. The injection event involved brief (factor of two) local spike in ~2 MeV electron fluxes. Measurements from the Los Alamos geosynchronous spacecraft, displaced eastward from the Van Allen probes, provided evidence for dispersive energy-time electron signatures consistent with injection and energization at the RBSP position. The Poynting flux also coincided with the energy peak in the up

  16. Van Allen Probe measurements of the electric drift E × B/B2 at Arecibo's L = 1.4 field line coordinate

    NASA Astrophysics Data System (ADS)

    Lejosne, Solène; Mozer, F. S.

    2016-07-01

    We have used electric and magnetic measurements by Van Allen Probe B from 2013 to 2014 to examine the equatorial electric drift E × B/B2 at one field line coordinate set to Arecibo's incoherent scatter radar location (L = 1.43). We report on departures from the traditional picture of corotational motion with the Earth in two ways: (1) the rotational angular speed is found to be 10% smaller than the rotational angular speed of the Earth, in agreement with previous works on plasmaspheric notches, and (2) the equatorial electric drift displays a dependence in magnetic local time, with a pattern consistent with the mapping of the Arecibo ionosphere dynamo electric fields along equipotential magnetic field lines. The electric fields due to the ionosphere dynamo are therefore expected to play a significant role when discussing, for instance, the structure and dynamics of the plasmasphere or the transport of trapped particles in the inner belt.

  17. Novel Estimates of ULF Wave Radial Diffusion of Relativistic Electrons in the Radiation Belts using the Van Allen Probes, THEMIS and GOES

    NASA Astrophysics Data System (ADS)

    Sarris, T. E.; Li, X.; Schiller, Q.

    2014-12-01

    Ultra-Low Frequency (ULF) waves are critical in radial diffusion processes of relativistic electrons in the radiation belts and their Power Spectral Density as a function of L is an integral part of the radial diffusion coefficients and of assimilative models of the radiation belts. Using simultaneous measurements from two GOES geosynchronous satellites, three spacecraft of the THEMIS constellation and the two Van Allen probes, we calculate the Power Spectral Density of ULF pulsations at different L, through which we provide improved estimates of the diffusion coefficient due to compressional magnetic perturbations as a function of L and Kp. These results can have significant implications in better defining the regions where radial diffusion can be effective vs. the regions where it cannot account for the observed changes in the phase space density of relativistic electrons.

  18. First evidence for chorus at a large geocentric distance as a source of plasmaspheric hiss: Coordinated THEMIS and Van Allen Probes observation

    NASA Astrophysics Data System (ADS)

    Li, W.; Chen, L.; Bortnik, J.; Thorne, R. M.; Angelopoulos, V.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.

    2015-01-01

    ray tracing suggests that plasmaspheric hiss can originate from chorus observed outside of the plasmapause. Although a few individual events have been reported to support this mechanism, the number of reported conjugate events is still very limited. Using coordinated observations between Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Van Allen Probes, we report on an interesting event, where chorus was observed at a large L shell (~9.8), different from previously reported events at L < 6, but still exhibited a remarkable correlation with hiss observed in the outer plasmasphere (L ~ 5.5). Ray tracing indicates that a subset of chorus can propagate into the observed location of hiss on a timescale of ~5-6 s, in excellent agreement with the observed time lag between chorus and hiss. This provides quantitative support that chorus from large L shells, where it was previously considered unable to propagate into the plasmasphere, can in fact be the source of hiss.

  19. Mission and instrumentation concept for the baryonic structure probe

    NASA Astrophysics Data System (ADS)

    Ebbets, Dennis; DeCino, James; Turner-Valle, Jennifer; Sembach, Kenneth

    2006-06-01

    There is a growing consensus that a substantial fraction of the matter in the universe, especially what we think of as normal baryonic matter, exists in a tenuous, hot filamentary intergalactic medium often referred to as the Cosmic Web. Improving our understanding of the web has been a high priority scientific goal in NASA's planning and roadmapping activities. NASA recently supported an Origins Probe study that explored the observable phenomenology of the web in detail and developed concepts for the instrumentation and mission. The Baryonic Structure Probe operates in the ultraviolet spectral region, using primarily O VI (λλ 1032, 1038 angstrom) and HI Ly α (λ 1216 angstrom) as tracers of the web. A productive investigation requires both moderate resolution (R = λ/Δλ ~ 30000) absorption line spectroscopy using faint background quasars as continuum sources, and imaging of the diffuse filaments in emission lines of the same ions. Spectroscopic sensitivity to quasars as faint as V ~ 19 will probe a large number of sight lines to derive physical diagnostics over the redshift range 0 < z < 1. Spectral imaging with a wide field of view and sensitivity to a redshift range 0 < z < 0.3 will map the filaments in a large volume of the universe after the web had evolved to near its modern structure. This paper summarizes the scientific goals, identifies the measurement requirements derived from them, and describes the instrument concepts and overall mission architecture developed by the BSP study team.

  20. Fast E-sail Uranus entry probe mission

    NASA Astrophysics Data System (ADS)

    Janhunen, Pekka; Lebreton, Jean-Pierre; Merikallio, Sini; Paton, Mark; Mengali, Giovanni; Quarta, Alessandro A.

    2014-12-01

    The electric solar wind sail is a novel propellantless space propulsion concept. According to numerical estimates, the electric solar wind sail can produce a large total impulse per propulsion system mass. Here we consider using a 0.5 N electric solar wind sail for boosting a 550 kg spacecraft to Uranus in less than 6 years. The spacecraft is a stack consisting of the electric solar wind sail module which is jettisoned roughly at Saturn distance, a carrier module and a probe for Uranus atmospheric entry. The carrier module has a chemical propulsion ability for orbital corrections and it uses its antenna for picking up the probe's data transmission and later relaying it to Earth. The scientific output of the mission is similar to what the Galileo Probe did at Jupiter. Measurements of the chemical and isotope composition of the Uranian atmosphere can give key constraints to different formation theories of the Solar System. A similar method could also be applied to other giant planets and Titan by using a fleet of more or less identical probes.

  1. RF communications subsystem for the Radiation Belt Storm Probes mission

    NASA Astrophysics Data System (ADS)

    Srinivasan, Dipak K.; Artis, David; Baker, Ben; Stilwell, Robert; Wallis, Robert

    2009-12-01

    The NASA Radiation Belt Storm Probes (RBSP) mission, currently in Phase B, is a two-spacecraft, Earth-orbiting mission, which will launch in 2012. The spacecraft's S-band radio frequency (RF) telecommunications subsystem has three primary functions: provide spacecraft command capability, provide spacecraft telemetry and science data return, and provide accurate Doppler data for navigation. The primary communications link to the ground is via the Johns Hopkins University Applied Physics Laboratory's (JHU/APL) 18 m dish, with secondary links to the NASA 13 m Ground Network and the Tracking and Data Relay Spacecraft System (TDRSS) in single-access mode. The on-board RF subsystem features the APL-built coherent transceiver and in-house builds of a solid-state power amplifier and conical bifilar helix broad-beam antennas. The coherent transceiver provides coherency digitally, and controls the downlink data rate and encoding within its field-programmable gate array (FPGA). The transceiver also provides a critical command decoder (CCD) function, which is used to protect against box-level upsets in the C&DH subsystem. Because RBSP is a spin-stabilized mission, the antennas must be symmetric about the spin axis. Two broad-beam antennas point along both ends of the spin axis, providing communication coverage from boresight to 70°. An RF splitter excites both antennas; therefore, the mission is designed such that no communications are required close to 90° from the spin axis due to the interferometer effect from the two antennas. To maximize the total downlink volume from the spacecraft, the CCSDS File Delivery Protocol (CFDP) has been baselined for the RBSP mission. During real-time ground contacts with the APL ground station, downlinked files are checked for errors. Handshaking between flight and ground CFDP software results in requests to retransmit only the file fragments lost due to dropouts. This allows minimization of RF link margins, thereby maximizing data rate and

  2. Using the cold plasma dispersion relation and whistler mode waves to quantify the antenna sheath impedance of the Van Allen Probes EFW instrument

    NASA Astrophysics Data System (ADS)

    Hartley, D. P.; Kletzing, C. A.; Kurth, W. S.; Bounds, S. R.; Averkamp, T. F.; Hospodarsky, G. B.; Wygant, J. R.; Bonnell, J. W.; Santolík, O.; Watt, C. E. J.

    2016-05-01

    Cold plasma theory and parallel wave propagation are often assumed when approximating the whistler mode magnetic field wave power from electric field observations. The current study is the first to include the wave normal angle from the Electric and Magnetic Field Instrument Suite and Integrated Science package on board the Van Allen Probes in the conversion factor, thus allowing for the accuracy of these assumptions to be quantified. Results indicate that removing the assumption of parallel propagation does not significantly affect calculated plasmaspheric hiss wave powers. Hence, the assumption of parallel propagation is valid. For chorus waves, inclusion of the wave normal angle in the conversion factor leads to significant alterations in the distribution of wave power ratios (observed/ calculated); the percentage of overestimates decreases, the percentage of underestimates increases, and the spread of values is significantly reduced. Calculated plasmaspheric hiss wave powers are, on average, a good estimate of those observed, whereas calculated chorus wave powers are persistently and systematically underestimated. Investigation of wave power ratios (observed/calculated), as a function of frequency and plasma density, reveals a structure consistent with signal attenuation via the formation of a plasma sheath around the Electric Field and Waves spherical double probes instrument. A simple, density-dependent model is developed in order to quantify this effect of variable impedance between the electric field antenna and the plasma interface. This sheath impedance model is then demonstrated to be successful in significantly improving agreement between calculated and observed power spectra and wave powers.

  3. The Hera Entry Probe Mission to Saturn, an ESA M-class mission proposal

    NASA Astrophysics Data System (ADS)

    Mousis, O.; Atkinson, D. H.; Spilker, T.; Venkatapathy, E.; Poncy, J.; Coustenis, A.; Reh, K.

    2015-10-01

    A fundamental goal of solar system exploration is to understand the origin of the solar system, the initial stages, conditions, and processes by which the solar system formed, how the formation process was initiated, and the nature of the interstellar seed material from which the solar system was born. Key to understanding solar system formation and subsequent dynamical and chemical evolution is the origin and evolution of the giant planets and their atmospheres. Additionally, the atmospheres of the giant planets serve as laboratories to better understand the atmospheric chemistries, dynamics, processes, and climates on all planets in the solar system including Earth, offer a context and provide a ground truth for exoplanets and exoplanetary systems,and have long been thought to play a critical role in the development of potentially habitable planetary systems. Remote sensing observations are limited when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the value of in situ probe measurements is illustrated by the exploration of Jupiter, where key measurements such as noble gases abundances and the precise measurement of the helium mixing ratio have only been made available through in situ measurements by the Galileo probe. Representing the only method providing ground-truth to connect the remote sensing inferences with physical reality, in situ measurements have only been accomplished twice in the history of outer solar system exploration, via the Galileo probe for Jupiter and the Huygens probe for Titan. In situ measurements provide access to atmospheric regions that are beyond the reach of remote sensing, enabling the dynamical, chemical and aerosol-forming processes at work from the thermosphere to the troposphere below the cloud decks to be studied. A proposal for a Saturn entry probe mission named Hera was recently submitted to the European Space Agency Medium Class mission announcement of

  4. Astrometric Gravitation Probe: a space mission concept for fundamental physics

    NASA Astrophysics Data System (ADS)

    Vecchiato, Alberto; Fienga, Agnes; Gai, Mario; Lattanzi, Mario G.; Riva, Alberto; Busonero, Deborah

    2015-08-01

    Modern technological developments have pushed the accuracy of astrometric measurements in the visible band down to the micro-arcsec level. This allows to test theories of gravity in the weak field limit to unprecedented level, with possible consequences spanning from the validity of fundamental physics principles, to tests of theories describing cosmological and galactic dynamics without resorting to Dark Matter and Dark Energy.This is the main goal of Astrometric Gravitation Probe (AGP) mission, which will be achieved by highly accurate astrometric determination of light deflection (as a modern rendition of the Dyson, Eddington, and Robertson eclipse experiment of 1919), aberration, and of the orbits of selected Solar System objects, with specific reference to the excess shift of the pericentre effect.The AGP concept was recently proposed for the recent call for ESA M4 missions as a collaboration among several scientists coming from many different European and US institutions. Its payload is based on a 1.15 m diameter telescope fed through a coronagraphic system by four fields, two set in symmetric positions around the Sun, and two in the opposite direction, all imaged on a CCD detector. Large parts of the instrument are common mode to all fields. The baseline operation mode is the scan of the ±1.13 deg Ecliptic strip, repeated for a minimum of 3 years and up to an optimal duration of 5 years. Operations and calibrations are simultaneous, defined in order to ensure common mode instrumental effects, identified and removed in data reduction. The astrometric and coronagraphic technologies build on the heritage of Gaia and Solar Orbiter.We review the mission concept and its science case, and discuss how this measurement concepts can be scaled to different mission implementations.

  5. NASA's Van Allen Probes RBSP-ECT Data Products and Access to Them: An Insider's Outlook on the Inner and Outer Belts (and We Don't Mean the Nation's Beltway...)

    NASA Astrophysics Data System (ADS)

    Smith, S. S.; Friedel, R. H. W.; Henderson, M. G.; Larsen, B.; Reeves, G. D.; Spence, H. E.

    2014-12-01

    In this poster, we present a summary of access to the data products of the Radiation Belt Storm Probes - Energetic Particle Composition, and Thermal plasma (RBSP-ECT) suite of NASA's Van Allen Probes mission. The RBSP-ECT science investigation (http://rbsp-ect.sr.unh.edu) measures comprehensively the near-Earth charged particle environment in order to understand the processes that control the acceleration, global distribution, and variability of radiation belt electrons and ions. RBSP-ECT data products derive from the three instrument elements that comprise the suite, which collectively covers the broad energies that define the source and seed populations, the core radiation belts, and also their highest energy ultra-relativistic extensions. These RBSP-ECT instruments include, from lowest to highest energies: the Helium, Oxygen, Proton, and Electron (HOPE) sensor, the Magnetic Electron and Ion Spectrometer (MagEIS), and the Relativistic Electron and Proton Telescope (REPT). We provide a brief overview of their principles of operation, as well as a description of the Level 1-3 data products that the HOPE, MagEIS, and REPT instruments produce, both separately and together. We provide a summary of how to access these RBSP-ECT data products at our Science Operation Center and Science Data Center (http://www.rbsp-ect.lanl.gov/rbsp_ect.php ) as well as caveats for their use. Finally, in the spirit of efficiently and effectively promoting and encouraging new collaborations, we present a summary of past publications, current studies, and opportunities for your future participation in RBSP-ECT science analyses.

  6. Statistics of VLF/ELF emissions at subauroral latitudes in Athabasca, Canada and their correspondence to the Van Allen Probes observations.

    NASA Astrophysics Data System (ADS)

    Martinez C, C.; Shiokawa, K.; Miyoshi, Y.; Keika, K.; Ozaki, M.; Schofield, I.; Connors, M. G.; Kletzing, C.

    2014-12-01

    Using a high-sampling rate (100 kHz) loop antenna installed at subauroral latitudes in Athabasca (ATH), Canada (54.7N, 246.7E, L=4) we have been able to continuously monitor VLF/ELF emissions since September 2012. Several types of VLF/ELF emissions were observed, including chorus, hiss and quasi-periodic emissions. We report statistics of VLF/ELF emissions using a one-year data set from November 1, 2012 until October 31, 2013. Using 10 minute and 24 hour spectra, we selected clearly defined emissions with a minimum intensity of 2.10-5 pT2/Hz and recorded their starting time, duration, frequency range and spectral characteristics. This data set allowed us to calculate their occurrence rate as a function of AE, Dst and other geomagnetic parameters. We found similar occurrence rates on the ground in all cases, showing a peak around 07 MLT (7-10%) and a minimum from 18 to 02 MLT (1-3%), in agreement with previous satellite measurements at the geomagnetic equator. However, occurrence rates on the ground can be 8 times lower than those observed at the equator. This could be caused by the ionosphere preventing some frequencies to go all the way through, but could also suggest an interference in the propagation process between the generation region in the geomagnetic equator and the ground. To investigate this, we compared this data set of VLF/ELF emissions with the observations made by the Van Allen Probes near the equatorial plane. We found 77 conjugate events for which the footprints of either the Van Allen Probes A or B (or both) were within 1000 km of ATH. Using the L2 magnetic field data from the EMFISIS instrument (CDF files available at https://emfisis.physics.uiowa.edu/), we were able to determine that the satellites observed VLF/ELF emissions for at least 54 of those events, suggesting that the spatial extent of the emissions is large. Within these events, we found 8 cases showing similar frequency and spectral features on the ground and on the satellite(s). We

  7. Comparing Local-Time and Storm-Phase Distributions of EMIC Waves Observed by Van Allen Probes A, GOES-13, and Halley, Antarctica

    NASA Astrophysics Data System (ADS)

    Ohnsted, M.; Engebretson, M. J.; Posch, J. L.; Lessard, M.; Singer, H. J.; Kletzing, C.; Smith, C. W.; Horne, R. B.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves are expected to be highly efficient in depleting the ring current and in removing outer radiation belt electrons. However, the distribution of these waves in subauroral regions has not been well characterized. In this study we present 0-5 Hz magnetic field data from the Van Allen Probes A (RBSP A) spacecraft (in elliptical equatorial orbit with apogee at 5.8 RE), 0-1 Hz data from GOES-13 (in geosynchronous orbit), and 0-5 Hz data from Halley, Antarctica (L ~4.6), during the first full local-time precession of the Van Allen Probes from October 2012 through July 2014. The considerably different hourly local time vs. L distributions observed point to distinct locations and geomagnetic activity-dependent patterns of EMIC wave activity. GOES-13 wave occurrences exhibited a broad peak in the noon-to-dusk sector. He+ band events peaked near dusk, while H+ band waves peaked near noon, with a secondary peak centered near dawn. More EMIC waves occurred during storm main phase in the He+ band (5%) than in the H+ band (1%), and 80% and 89% of the He+ and H+ band waves, respectively, occurred under late storm recovery or quiet conditions. During all storm phases the local time occurrence patterns of < 0.4 Hz and 0.4-1.0 Hz events at Halley resembled those of He+ and H+ band waves, respectively, at GOES-13. The relatively few wave events at Halley with f > 1.0 Hz occurred at all local times, but with a modest, broad peak near dawn. Roughly 90% of both the 1570 Halley events < 1.0 Hz and the 142 Halley events > 1.0 Hz occurred during late storm recovery and quiet conditions. Events during compressions at GOES-13 (10%), Halley (6%), and RBSP A (6%) peaked near local noon, but with a secondary peak near midnight. Waves observed by RBSP A were distributed rather evenly in local time in all L shell ranges between 3 and 6, and the percentage occurring during late storm recovery or quiet conditions was only 65%. We interpret the difference in

  8. A Preliminary Study of a Solar-Probe Mission

    NASA Technical Reports Server (NTRS)

    Dugan, Duane W.

    1961-01-01

    A preliminary study is made of some problems associated with the sending of an instrumented probe close to the Sun for the purpose of gathering and telemetering back to Earth information concerning solar phenomena and circumsolar space. The problems considered are primarily those relating to heating and to launch requirements. A nonanalytic discussion of the communications problem of a solar-probe mission is presented to obtain order-of-magnitude estimates of the output and weight of an auxiliary power supply which might be required. From the study it is believed that approaches to the Sun as close as about 4 or 5 million miles do not present insuperable difficulties insofar as heating and communications are concerned. Guidance requirements, in general, do not appear to be stringent. However, in terms of current experience, velocity requirements may be large. It is found, for example, that to achieve perihelion distances between the orbit of Mercury and the visible disc of the Sun, total burnout velocities ranging between 50,000 and 100,000 feet per second are required.

  9. Science Planning for the Solar Probe Plus NASA Mission

    NASA Astrophysics Data System (ADS)

    Kusterer, M. B.; Fox, N. J.; Turner, F. S.; Vandegriff, J. D.

    2015-12-01

    With a planned launch in 2018, there are a number of challenges for the Science Planning Team (SPT) of the Solar Probe Plus mission. The geometry of the celestial bodies and the spacecraft during some of the Solar Probe Plus mission orbits cause limited uplink and downlink opportunities. The payload teams must manage the volume of data that they write to the spacecraft solid-state recorders (SSR) for their individual instruments for downlink to the ground. The aim is to write the instrument data to the spacecraft SSR for downlink before a set of data downlink opportunities large enough to get the data to the ground and before the start of another data collection cycle. The SPT also intend to coordinate observations with other spacecraft and ground based systems. To add further complexity, two of the spacecraft payloads have the capability to write a large volumes of data to their internal payload SSR while sending a smaller "survey" portion of the data to the spacecraft SSR for downlink. The instrument scientists would then view the survey data on the ground, determine the most interesting data from their payload SSR, send commands to transfer that data from their payload SSR to the spacecraft SSR for downlink. The timing required for downlink and analysis of the survey data, identifying uplink opportunities for commanding data transfers, and downlink opportunities big enough for the selected data within the data collection period is critical. To solve these challenges, the Solar Probe Plus Science Working Group has designed a orbit-type optimized data file priority downlink scheme to downlink high priority survey data quickly. This file priority scheme would maximize the reaction time that the payload teams have to perform the survey and selected data method on orbits where the downlink and uplink availability will support using this method. An interactive display and analysis science planning tool is being designed for the SPT to use as an aid to planning. The

  10. Calculating ultra-low-frequency wave power of the compressional magnetic field vs. L and time: multi-spacecraft analysis using the Van Allen probes, THEMIS and GOES

    NASA Astrophysics Data System (ADS)

    Sarris, Theodore E.; Li, Xinlin

    2016-06-01

    Ultra-low-frequency (ULF) pulsations are critical in radial diffusion processes of energetic particles, and the power spectral density (PSD) of these fluctuations is an integral part of the radial diffusion coefficients and of assimilative models of the radiation belts. Using simultaneous measurements from two Geostationary Operational Environmental Satellites (GOES) geosynchronous satellites, three satellites of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft constellation and the two Van Allen probes during a 10-day period of intense geomagnetic activity and ULF pulsations of October 2012, we calculate the PSDs of ULF pulsations at different L shells. By following the time history of measurements at different L it is shown that, during this time, ULF wave power is not enhanced uniformly throughout the magnetosphere but instead is mostly enhanced in the outer L shells, close to the magnetopause, and to a lesser extent in the inner magnetosphere, closer to the plasmapause. Furthermore, by using phase differences between two GOES geosynchronous satellite pairs, we estimate the daily-averaged distribution of power at different azimuthal wave numbers. These results can have significant implications in better defining the effect of radial diffusion in the phase space density of energetic particles for different wave numbers or L shell distributions of ULF power.

  11. Van Allen Probes based investigation of storm time enhancements in the duskward electric field to lower L shells and its effect on ring current formation and plasmasphere erosion.

    NASA Astrophysics Data System (ADS)

    Thaller, S. A.; Wygant, J. R.; Dai, L.; Breneman, A. W.; Kersten, K.; Kletzing, C.; Kurth, W. S.; De Pascuale, S.; Bonnell, J. W.; Hospodarsky, G. B.; Gkioulidou, M.; Fennell, J. F.

    2014-12-01

    The large scale convection electric field plays a central role in the dynamics of the inner magnetosphere; among which processes are ring current particle injection and plasmasphere erosion. Both of these are important for radiation belt dynamics. The ring current affects magnetic field geometry which in turn affects particle drift paths and plasmasphere erosion shrinks the region characterized by plasmaspheric hiss which would otherwise be present to scatter population of radiation belt seed electrons. Using the Van Allen Probes we investigate enhancements in the duskward electric field to lower L shells (L < 4 RE) and its role in ring current particle energization and erosion of the plasmasphere during two major storms; June 1, 2013 and February 19, 2014. During these storms, the electric field enhanced to low L shells with magnitudes ~1-2 mV/m in the co-rotating frame. The corresponding storm time ring current enhancements and plasmasphere erosions are examined in the context of these electric fields. The intensification in the duskward electric field is of long enough duration to transport particles from locations characteristic of the earthward edge of the plasma sheet (L shells ~ 8-10 RE) to the observed location of the ring current while energizing them though conservation of the first adiabatic invariant to energies typical of the ring current. It is also observed that the range in L shell over which the most intense nightside, duskward, electric field is observed is also that over which the higher pressure region of the ring current is located.

  12. Variation in crossover frequency of EMIC waves in plasmasphere estimated from ion cyclotron whistler waves observed by Van Allen Probe A

    NASA Astrophysics Data System (ADS)

    Matsuda, Shoya; Kasahara, Yoshiya; Kletzing, Craig A.

    2016-01-01

    We report variations in the propagation of the H+ band ion cyclotron whistlers observed by Van Allen Probe A. Ion cyclotron whistlers are one of the EMIC (electromagnetic ion cyclotron) waves generated by mode conversion from lightning whistlers. Crossover frequency is an important frequency for the ion cyclotron whistlers, which is a function of the variations in the local heavy-ion composition. We surveyed waveform data obtained by the Electric and Magnetic Field Instrument and Integrated Science instrument and found that 3461 H+ band ion cyclotron whistlers were observed from 572 km to 5992 km in altitude. The main finding is that the crossover frequencies of the observed events decreased with increasing altitude. These results support the hypothesis that the total heavy-ion density decreases with increasing altitude. Furthermore, in 96% of all observed events, the crossover frequencies exceeded 0.5fH+, which suggests that the EMIC dispersion relation contains a frequency gap of around 0.5fH+.

  13. A Dream of a Mission: Stellar Imager and Seismic Probe

    NASA Technical Reports Server (NTRS)

    Carpenter, Kenneth G.; Schrijver, Carolus J.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    The Stellar Imager and Seismic Probe (SISP) is a mission to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. SISP will zoom in on what today - with few exceptions - we only know as point sources, revealing processes never before seen, thus providing a tool to astrophysics as fundamental as the microscope is to the study of life on Earth. SISP is an ultraviolet aperture-synthesis imager with 8-10 telescopes with meter-class apertures, and a central hub with focal-plane instrumentation that allows spectrophotometry in passbands as narrow as a few Angstroms up to hundreds of Angstroms. SISP will image stars and binaries with one hundred to one thousand resolution elements on their surface, and sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations; this will provide accurate knowledge of stellar structure and evolution and complex transport processes, and will impact numerous branches of (astro)physics ranging from the Big Bang to the future of the Universe. Fitting naturally within the NASA long-term time line, SISP complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets.

  14. Initial measurements of O-ion and He-ion decay rates observed from the Van Allen probes RBSPICE instrument

    PubMed Central

    Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro

    2014-01-01

    H-ion (∼45 keV to ∼600 keV), He-ion (∼65 keV to ∼520 keV), and O-ion (∼140 keV to ∼1130 keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first 9 months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L shells, on the order of ∼0.8 day at L shells of 3–4, and decay more slowly with higher L shell, on the order of ∼1.7 days at L shells of 5–6. Conversely, O-ions decay very rapidly (∼1.5 h) across all L shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher-energy (> 500 keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high-energy O-ion loss rates, which have not been adequately studied in the literature to date. Key Points We report initial observations of ring current ions We show that He-ion decay rates are consistent with theory We show that O-ions with energies greater than 500 keV decay very rapidly PMID:26167435

  15. Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

    NASA Astrophysics Data System (ADS)

    Jaynes, A. N.; Lessard, M. R.; Takahashi, K.; Ali, A. F.; Malaspina, D. M.; Michell, R. G.; Spanswick, E. L.; Baker, D. N.; Blake, J. B.; Cully, C.; Donovan, E. F.; Kletzing, C. A.; Reeves, G. D.; Samara, M.; Spence, H. E.; Wygant, J. R.

    2015-10-01

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4-5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorus waves and an apparent field line resonance (in the Pc4-5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4-5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. Such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.

  16. Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

    SciTech Connect

    Jaynes, A. N.; Lessard, M. R.; Takahashi, K.; Ali, A. F.; Malaspina, D. M.; Michell, R. G.; Spanswick, E. L.; Baker, D. N.; Blake, J. B.; Cully, C.; Donovan, E. F.; Kletzing, C. A.; Reeves, G. D.; Samara, M.; Spence, H. E.; Wygant, J. R.

    2015-10-28

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4–5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorus waves and an apparent field line resonance (in the Pc4–5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4–5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. As a result, such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.

  17. Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

    DOE PAGESBeta

    Jaynes, A. N.; Lessard, M. R.; Takahashi, K.; Ali, A. F.; Malaspina, D. M.; Michell, R. G.; Spanswick, E. L.; Baker, D. N.; Blake, J. B.; Cully, C.; et al

    2015-10-28

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4–5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorusmore » waves and an apparent field line resonance (in the Pc4–5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4–5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. As a result, such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.« less

  18. Solar Probe: A Mission to the Sun and the Inner Core of the Heliosphere

    NASA Technical Reports Server (NTRS)

    Tsurutani, B.; Gloeckler, G.; Feldman, W.; Habbal, S.; McNutt, R.; Randolph, J.; Title, A.

    1998-01-01

    Following a brief review of out current knowledge of the solar wind and processes on the solar surface, we describe the baseline Solar Probe mission, its prime scientific objectives and its strawman instrument payload.

  19. The electrical performance of Ag Zn batteries for the Venus multi-probe mission

    NASA Technical Reports Server (NTRS)

    Palandati, C.

    1975-01-01

    An evaluation of 5 Ah and 21 Ah Silver-Zinc batteries was made to determine their suitability to meet the energy storage requirements of the bus vehicle, 3 small probes and large probe for the Venus multi-probe mission. The evaluation included a 4 Ah battery for the small probe, a 21 Ah battery for the large probe, one battery of each size for the bus vehicle power, a periodic cycling test on each size battery and a wet stand test of charged and discharged cells of both cell designs. The study on the probe batteries and bus vehicle batteries included both electrical and thermal simulation for the entire mission. The effects on silver migration and zinc penetration of the cellophane separators caused by the various test parameters were determined by visual and X-ray fluorescence analysis. The 5 Ah batteries supported the power requirements for the bus vehicle and small probe. The 21 Ah large probe battery supplied the required mission power. Both probe batteries delivered in excess of 132 percent of rated capacity at the completion of the mission simulation.

  20. Science investigation options with a NASA New Frontiers Program Saturn entry probe mission

    NASA Astrophysics Data System (ADS)

    Spilker, T. R.; Atreya, S. K.; Atkinson, D. H.; Colaprete, A.; Coustenis, A.

    2012-09-01

    In 2011 the Space Studies Board of the US National Research Council released its report, "Vision and Voyages for Planetary Science in the Decade 2013- 2022" [1] (PSDS). This document is intended to be the guiding document for NASA's planetary science and space flight mission priorities for that decade. The PSDS treats three classes of flight missions: small, medium, and large. Small missions are ones that could be flown within the resource constraints of NASA's Discovery Program, a program of PI-led, competed missions, including a US 500 million (FY 2015) recommended cost cap, excluding the launch vehicle. The PSDS makes no specific recommendations for science objectives or destinations for small missions. Medium missions could be flown under NASA's New Frontiers Program, also a program of PI-led, competed missions, with a recommended cost cap of US 1 billion excluding the launch vehicle. Both of these competed mission programs have been highly successful, with multiple spacecraft currently in flight and more either under development or in the final steps of competition. Large missions, generally called flagship missions, would have total mission costs exceeding US $1 billion and would be directed by NASA, not PI-led. Unlike Small class missions, the PSDS recommends specific science objectives for Medium class missions. Four Medium class mission concepts and their science objectives carry over from the previous PSDS [2]: • Comet Surface Sample Return • Lunar South-Pole Aitken Basin Sample Return • Trojan Tour and Rendezvous • Venus In Situ Explorer The current PSDS adds a fifth mission concept to the list for the next New Frontiers Program AO ("NF-4"), currently anticipated in 2016: a Saturn probe mission. This mission would deliver an atmospheric entry probe into Saturn's atmosphere to make composition and atmospheric structure measurements critical to understanding the materials, processes, and time scales of Saturn's formation, and by comparison to

  1. The energetic particle environment of the solar probe mission: As estimated by the participants of the Solar Probe Environment Workshop

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.; Fisk, L. A.; Gold, R. E.; Lin, R. P.; Newkirk, G.; Simpson, J. A.; Vanhollebeke, M. A. I.

    1978-01-01

    NASA's long-range plan for the study of solar-terrestrial relations includes a Solar Probe Mission in which a spacecraft is placed in an eccentric orbit with perihelion at four solar radii. Possible radiation damage to the spacecraft and mission from energetic particles was discussed at a Solar Probe Environment Workshop which concluded that it would be unlikely for such a spacecraft to suffer fatal radiation damage, although a severe problem exists in limiting the neutron flux from a radioactive power supply enough to allow solar neutrons to be detected.

  2. Variability of the pitch angle distribution of radiation belt ultrarelativistic electrons during and following intense geomagnetic storms: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Zou, Z.; Ni, B.; Gu, X.; Zhao, Z.; Zhou, C.

    2015-12-01

    Fifteen month of pitch angle resolved Van Allen Probes Relativistic Electron-Proton Telescope (REPT) measurements of differential electron flux are analyzed to investigate the characteristics of the pitch angle distribution of radiation belt ultrarelativistic(> 2 MeV) electrons during storm conditions and during the long-storm decay. By modeling the ultrarelativistic electron pitch angle distribution as ,where is the equatorial pitch angle we examine the spatiotemporal variations of n value. The results show that in general n values increases with the level of geomagnetic activity. In principle the ultrarelativistic electrons respond to geomagnetic storms by becoming peaked at 90° pitch angle with n-values of 2 - 3 as a supportive signature of chorus acceleration outside the plasmasphere. High n-values also exists inside the plasmasphere, being localized adjacent to the plasmapause and energy dependent, which suggests a significant contribution from electronmagnetic ion cyclotron (EMIC) waves scattering. During quiet periods, n values generally evolve to become small, i.e., 0-1. The slow and long-term decays of the ultrarelativistic electrons after geomagnetic storms, while prominent, produce energy and L-shell-dependent decay time scales in association with the solar and geomagnetic activity and wave-particle interaction processes. At lower L shells inside the plasmasphere, the decay time scales for electrons at REPT energies are generally larger, varying from tens of days to hundreds of days, which can be mainly attributed to the combined effect of hiss-induced pitch angle scattering and inward radial diffusion. As L shell increases to L~3.5, a narrow region exists (with a width of ~0.5 L), where the observed ultrarelativistic electrons decay fastest, possibly resulting from efficient EMIC wave scattering. As L shell continues to increase, generally becomes larger again, indicating an overall slower loss process by waves at high L shells. Our investigation based

  3. Variability of the pitch angle distribution of radiation belt ultrarelativistic electrons during and following intense geomagnetic storms: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Zou, Zhengyang; Gu, Xudong; Zhou, Chen; Thorne, Richard M.; Bortnik, Jacob; Shi, Run; Zhao, Zhengyu; Baker, Daniel N.; Kanekal, Shrikhanth G.; Spence, Harlan E.; Reeves, Geoffrey D.; Li, Xinlin

    2015-06-01

    Fifteen months of pitch angle resolved Van Allen Probes Relativistic Electron-Proton Telescope (REPT) measurements of differential electron flux are analyzed to investigate the characteristic variability of the pitch angle distribution of radiation belt ultrarelativistic (>2 MeV) electrons during storm conditions and during the long-term poststorm decay. By modeling the ultrarelativistic electron pitch angle distribution as sinnα, where α is the equatorial pitch angle, we examine the spatiotemporal variations of the n value. The results show that, in general, n values increase with the level of geomagnetic activity. In principle, ultrarelativistic electrons respond to geomagnetic storms by becoming more peaked at 90° pitch angle with n values of 2-3 as a supportive signature of chorus acceleration outside the plasmasphere. High n values also exist inside the plasmasphere, being localized adjacent to the plasmapause and exhibiting energy dependence, which suggests a significant contribution from electromagnetic ion cyclotron (EMIC) wave scattering. During quiet periods, n values generally evolve to become small, i.e., 0-1. The slow and long-term decays of the ultrarelativistic electrons after geomagnetic storms, while prominent, produce energy and L-shell-dependent decay time scales in association with the solar and geomagnetic activity and wave-particle interaction processes. At lower L shells inside the plasmasphere, the decay time scales τd for electrons at REPT energies are generally larger, varying from tens of days to hundreds of days, which can be mainly attributed to the combined effect of hiss-induced pitch angle scattering and inward radial diffusion. As L shell increases to L~3.5, a narrow region exists (with a width of ~0.5 L), where the observed ultrarelativistic electrons decay fastest, possibly resulting from efficient EMIC wave scattering. As L shell continues to increase, τd generally becomes larger again, indicating an overall slower loss

  4. ExoExoZodi Mapper: a starshade probe mission

    NASA Astrophysics Data System (ADS)

    Glassman, Tiffany; Lo, Amy

    2012-09-01

    Direct detection and imaging of Exo-Earths is a prime candidate for the next Astrophysics flagship mission. Much effort is focused on developing the mission concept and technology to enable the direct imaging of an Exo-Earth. However, several key astronomical unknowns stand in the way of a fully optimized Exo-Earth imaging mission, the primary of which is the uncertainty in the Exo-Zodi brightness. By analogy to our own Zodiacal dust, Exo-Zodiacal dust is predicted to exist in the habitable zones of other stars, exactly in the locations where Exo-Earths would reside. Reflected light from this dust could be a primary background contribution to measurements of the Exo-Earth. We propose a mission concept called the Exo-Zodi Mapper (EZM) to obtain definitive measurements of the brightness of the Exo-Zodi dust around target stars which are the prime targets for a future mission aimed at the direct detection of Exo-Earths. Our mission concept uses a medium sized starshade that works with the James Webb Space Telescope to image and characterize the brightness and distribution of Exo-Zodiacal dust around ~40 primary target stars. This measurement would provide more precise requirements for the eventual Exo-Earth flagship mission, which may translate into significant savings. In addition, EZM can provide a host of ancillary science information on these important targets, including detailed maps of their dust distribution, studies of outer, giant planets, and exploration of the overall architecture of these planetary systems. The EZM starshade can also be used to enable high-contrast imaging of other targets of value to the astronomical community such as debris disks around young stars. We present an overview of the science that motivated the mission concept, the driving requirements, and the top level mission architecture.

  5. Exoplanet Direct Imaging: Coronagraph Probe Mission Study EXO-C

    NASA Technical Reports Server (NTRS)

    Stapelfeldt, Karl R.

    2013-01-01

    Flagship mission for spectroscopy of ExoEarths is a long-term priority for space astrophysics (Astro2010). Requires 10(exp 10) contrast at 3 lambda/D separation, ( (is) greater than 10,000 times beyond HST performance) and large telescope (is) greater than 4m aperture. Big step. Mission for spectroscopy of giant planets and imaging of disks requires 10(exp 9) contrast at 3 lambda/D (already demonstrated in lab) and (is) approximately 1.5m telescope. Should be much more affordable, good intermediate step.Various PIs have proposed many versions of the latter mission 17 times since 1999; no unified approach.

  6. Laser driven light sails: An examination of the possibilities for interstellar probes and other missions

    NASA Technical Reports Server (NTRS)

    Rather, J. D. G.; Zeiders, G. W.; Vogelsang, K. R.

    1976-01-01

    A theoretical discussion of high energy laser propelled light sails is presented. Selection of sail materials, interstellar drag forces, beam pointing, flight velocity, probe mass, and radiation shielding are among the factors discussed. Interstellar probe missions and colonization of the solar system via the light sail are considered.

  7. Pioneer III Probe

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Looking more like surgeons, these technicians wearing 'cleanroom' attire inspect the Pioneer III probe before shipping it to Cape Canaveral, Florida. Pioneer III was launched on December 6, 1958 aboard a Juno II rocket at the Atlantic Missile Range, Cape Canaveral, Florida. The mission objectives were to measure the radiation intensity of the Van Allen radiation belt, test long range communication systems, the launch vehicle and other subsystems. The Juno II failed to reach proper orbital escape velocity. The probe re-entered the Earth's atmosphere on December 7th ending its brief mission.

  8. The Exo-S probe class starshade mission

    NASA Astrophysics Data System (ADS)

    Seager, Sara; Turnbull, Margaret; Sparks, William; Thomson, Mark; Shaklan, Stuart B.; Roberge, Aki; Kuchner, Marc; Kasdin, N. Jeremy; Domagal-Goldman, Shawn; Cash, Webster; Warfield, Keith; Lisman, Doug; Scharf, Dan; Webb, David; Trabert, Rachel; Martin, Stefan; Cady, Eric; Heneghan, Cate

    2015-09-01

    Exo-S is a direct imaging space-based mission to discover and characterize exoplanets. With its modest size, Exo-S bridges the gap between census missions like Kepler and a future space-based flagship direct imaging exoplanet mission. With the ability to reach down to Earth-size planets in the habitable zones of nearly two dozen nearby stars, Exo-S is a powerful first step in the search for and identification of Earth-like planets. Compelling science can be returned at the same time as the technological and scientific framework is developed for a larger flagship mission. The Exo-S Science and Technology Definition Team studied two viable starshade-telescope missions for exoplanet direct imaging, targeted to the $1B cost guideline. The first Exo-S mission concept is a starshade and telescope system dedicated to each other for the sole purpose of direct imaging for exoplanets (The "Starshade Dedicated Mission"). The starshade and commercial, 1.1-m diameter telescope co-launch, sharing the same low-cost launch vehicle, conserving cost. The Dedicated mission orbits in a heliocentric, Earth leading, Earth-drift away orbit. The telescope has a conventional instrument package that includes the planet camera, a basic spectrometer, and a guide camera. The second Exo-S mission concept is a starshade that launches separately to rendezvous with an existing on-orbit space telescope (the "Starshade Rendezvous Mission"). The existing telescope adopted for the study is the WFIRST-AFTA (Wide-Field Infrared Survey Telescope Astrophysics Focused Telescope Asset). The WFIRST-AFTA 2.4-m telescope is assumed to have previously launched to a Halo orbit about the Earth-Sun L2 point, away from the gravity gradient of Earth orbit which is unsuitable for formation flying of the starshade and telescope. The impact on WFIRST-AFTA for starshade readiness is minimized; the existing coronagraph instrument performs as the starshade science instrument, while formation guidance is handled by the

  9. Gravitational experiments on a solar probe mission: Scientific objectives and technology considerations

    NASA Technical Reports Server (NTRS)

    Anderson, John D.

    1989-01-01

    The concept of a solar impact probe (either solar plunger or sun grazer) led to the initiation of a NASA study at JPL in 1978 on the engineering and scientific feasibility of a Solar Probe Mission, named Starprobe, in which a spacecraft is placed in a high eccentricity orbit with a perihelion near 4 solar radii. The Starprobe study showed that the concept was feasible and in fact preliminary mission and spacecraft designs were developed. In the early stages of the Solar Probe studies the emphasis was placed on gravitational science, but by the time of a workshop at Caltech in May 1978 (Neugebauer and Davies, 1978) there was about an equal division of interest between heliospheric physics and gravitation. The last of the gravitational studies for Solar Probe was conducted at JPL in 1983. Since that time, the Committee on Solar and Space Physics (CSSP) of the National Academy of Sciences has recommended the pursuit of a focused mission, featuring fields and particles instrumentation and emphasizing studies of the solar wind source region. Such a solar probe mission is currently listed as the 1994 Major New Star candidate. In the remainder of this review, the unique gravitational science that can be accomplished with a solar probe mission is reviewed. In addition the technology issues that were identified in 1980 by the ad hoc working group for Gravity and Relativity Science are addressed.

  10. New Results About the Earth’s Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Baker, Daniel

    2015-01-01

    The first great scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or 'belts', of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons in the energy range 100 keV < E< 1 MeV often populated both the inner and outer zones with a pronounced 'slot' region relatively devoid of energetic electrons existing between them. This two-belt structure for the Van Allen moderate-energy electron component was explained as being due to strong interactions of electrons with electromagnetic waves just inside the cold plasma (plasmapause) boundary. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. However, recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed wholly unexpected properties of the radiation belts, especially at highly relativistic (E > 2 MeV) and ultra-relativistic (E > 5 MeV) kinetic energies. In this presentation we show using high spatial and temporal resolution data from the Relativistic Electron-Proton Telescope (REPT) experiment on board the Van Allen Probes that multiple belts can exist concurrently and that an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Using additionally available Van Allen Probes data, we demonstrate that these remarkable features of energetic electrons are not due to a physical boundary within Earth's intrinsic magnetic field. Neither is it likely that human-generated electromagnetic transmitter wave fields might produce such effects. Rather, we conclude from these unique measurements that slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle

  11. Coordinated science with the Solar Orbiter, Solar Probe Plus, Interhelioprobe and SPORT missions

    NASA Astrophysics Data System (ADS)

    Maksimovic, Milan; Vourlidas, Angelos; Zimovets, Ivan; Velli, Marco; Zhukov, Andrei; Kuznetsov, Vladimir; Liu, Ying; Bale, Stuart; Ming, Xiong

    The concurrent science operations of the ESA Solar Orbiter (SO), NASA Solar Probe Plus (SPP), Russian Interhelioprobe (IHP) and Chinese SPORT missions will offer a truly unique epoch in heliospheric science. While each mission will achieve its own important science objectives, taken together the four missions will be capable of doing the multi-point measurements required to address many problems in Heliophysics such as the coronal origin of the solar wind plasma and magnetic field or the way the Solar transients drive the heliospheric variability. In this presentation, we discuss the capabilities of the four missions and the Science synergy that will be realized by concurrent operations

  12. An Update on the FIRE (Solar Probe) Mission

    NASA Technical Reports Server (NTRS)

    Randolph, James E.

    1995-01-01

    A joint U.S.-Russian mission to the sun named FIRE is currently being planned. The mission consists of two spacecraft, one U.S. built and the other Russian built. Both spacecraft will be launched from a single vehicle, separate after launch, travel to Jupiter for a gravity assist that will maneuver the spacecraft into highly elliptical polar orbits about the sun. The U.S. spacecraft will have a perihelion of 4 Rs and the Russian 10 Rs. A full complement of in situ fields and particles instruments are planned for both spacecraft to measure acceleration mechanisms and other characteristics of the solar wind. The strawman payloads and expected science return will be discussed.

  13. Earthquake-Lightning Signature Probed by Tropical Rainfall Measuring Mission

    NASA Astrophysics Data System (ADS)

    Lee, Hao; Liu, Jann-Yenq Tiger

    2016-04-01

    The lightning activity is one of the key parameters to understand the atmospheric electric fields near the Earth's surface and the lithosphere-atmosphere-ionosphere coupling during the earthquake preparation period. A statistical study shows more lightning before magnitude M>=5.0 earthquakes in Taiwan during 1993-2004. In this paper, the Lightning Imaging Sensor (LIS) onboard Tropical Rainfall Measuring Mission (TRMM) is used to statistically exam the lightning activity 30 days before and after 198 M>=7.0 earthquakes in the tropical area of the globe during the 17-year period of 1988-2014. The statistical results show that lightning activities over epicenter significantly enhance before the earthquakes.

  14. A close-up of the sun. [solar probe mission planning conference

    NASA Technical Reports Server (NTRS)

    Neugebauer, M. (Editor); Davies, R. W. (Editor)

    1978-01-01

    NASA's long-range plan for the study of solar-terrestrial relations includes a Solar Probe Mission in which a spacecraft is put into an eccentric orbit with perihelion near 4 solar radii (0.02 AU). The scientific experiments which might be done with such a mission are discussed. Topics include the distribution of mass within the Sun, solar angular momentum, the fine structure of the solar surface and corona, the acceleration of the solar wind and energetic particles, and the evolution of interplanetary dust. The mission could also contribute to high-accuracy tests of general relativity and the search for cosmic gravitational radiation.

  15. Gradiometry coexperiments to the gravity probe B and step missions

    SciTech Connect

    Tapley, M.; Breakwell, J.; Everitt, C.W.F.; Vanpatten, R.; Worden, P.

    1990-01-01

    The Gravity Probe-B (GP-B) spacecraft, designed to test predictions of general relativity, will fly in the mid 1990s. It will carry four electrostatically suspended gyroscopes in a cryogenic environment and will have a drag-free control system to minimize disturbances on the gyroscopes. The Stanford Test of Equivalence Principle (STEP) spacecraft, to fly later, will carry a set of test masses under very similar conditions. The possibility of using differential measurements of the GP-B gyroscopes suspension forces and the STEP tests mass displacement readout to form single-axis gravity gradiometers is explored. It is shown that the noise in the suspension systems is sufficiently small in the relevant frequency range, and that enough information is collected to compensate for the spacecrafts' attitude motion. Finally, using Breakwell's flat-earth approximation, these experiments are compared to other geodesy experiments and predict the contribution they can make to the knowledge of the Earth's geopotential.

  16. Contingency Planning for the Microwave Anisotropy Probe Mission

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Rohrbaugh, David; Schiff, Conrad; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) utilized a phasing loop/lunar encounter strategy to achieve a small amplitude Lissajous orbit about the Sun-Earth/Moon L2 libration point. The use of phasing loops was key in minimizing MAP's overall deltaV needs while also providing ample opportunities for contingency resolution. This paper will discuss the different contingencies and responses studied for MAP. These contingencies included accommodating excessive launch vehicle errors (beyond 3 sigma), splitting perigee maneuvers to achieve ground station coverage through the Deep Space Network (DSN), delaying the start of a perigee maneuver, aborting a perigee maneuver in the middle of execution, missing a perigee maneuver altogether, and missing the lunar encounter (crucial to achieving the final Lissajous orbit). It is determined that using a phasing loop approach permits many opportunities to correct for a majority of these contingencies.

  17. CASSIOPE Enhanced Polar Outflow Probe (e-POP) Mission Overview

    NASA Astrophysics Data System (ADS)

    Yau, A. W.; James, H. G.

    2015-06-01

    The Enhanced Polar Outflow Probe (e-POP) on the polar-orbiting CASSIOPE small satellite (325×1500 km, 80° inclination) is a suite of 8 plasma instruments, including imaging plasma and neutral particle sensors, magnetometers, dual-frequency Global Positioning System (GPS) receivers, charge coupled-device (CCD) cameras, a radio wave receiver and a beacon transmitter. The scientific objective of e-POP is to make observations of mesoscale and microscale plasma processes in the topside high-latitude ionosphere at the highest-possible resolution, specifically to study the microscale characteristics of plasma outflow and related acceleration processes, the occurrence morphology of neutral escape, and the effects of auroral currents on plasma outflow and those of plasma microstructures on radio propagation: the strategy is to use the large data storage and high-speed telemetry downlink capacity of a companion, experimental communications payload on board CASSIOPE to support the high-resolution observations of particle distributions, waves and magnetic fields to 10-ms time scale (˜100 m spatial scale) and the imaging of the aurora on 100-ms time scale, as well as imaging studies of the ionosphere in conjunction with ground-based transmitters and ground receiving stations on comparable (10-100 ms) time scales.

  18. Comparative Planetology at Saturn: Mission Concept for a Flyby with Shallow Probes

    NASA Astrophysics Data System (ADS)

    Dawson, Olivia R.; Strong, S.; Likar, J.; Watson, A.; Balint, T.; Aubrey, A.; Bramall, N.; Chereck, A.; Dominguez, G.; Hultgren, E.; Levy, J.; Liu, T.; Elwood Madden, M.; Plesko, C.; Sigel, D.; Soderlund, K.; Takahashi, Y.; Thompson, S.; Thomson, B.; Wiese, D.

    2006-12-01

    As part of the 2006 NASA JPL Planetary Science Summer School, we conducted a trade study of an innovative New Frontiers class mission concept that would measure essential elemental abundances in Saturn’s atmosphere. Characterizing the abundance of heavy elements (mass > 4He) and dynamical processes at depth in the outer planets is vital to understanding the origin and evolution of the Solar System and, consequentially, extra-solar systems (Atreya, S.K. et al., 2006). Comparing the heavy element abundance ratios among the Sun and outer planets is required to refine Solar System formation scenarios. Since water was presumably the primary carrier of heavy elements to the outer planets, quantifying the O/H ratio is critical to determining the enrichment factor of the gas giants’ composition with respect to solar values. Elemental abundance information, including water content, will be available for Jupiter following Juno’s primary mission completion in 2017, but comparable data for Saturn is not, and cannot be provided by the Cassini mission. There are no in situ measurements of Saturn to date. Water (hence O/H) abundance may only be accurately ascertained deep in Saturn’s well-mixed atmosphere, where high temperatures and pressures make in situ data collection challenging. Our mission design, proposed for a 2015 launch, consists of a fly-by spacecraft that would release two identical instrument-carrying probes into different locations in Saturn’s atmosphere. The probes would gather in situ measurements down to at least 10 bars, to characterize the atmospheric composition and dynamics, and would also measure the water content down to 100 bars using the remote sensing technique of microwave radiometry. Here we discuss the detailed mission design of the fly-by carrier spacecraft and the probes, illustrating the feasibility of our mission concept and the ground-breaking science and engineering that would ensue from a successful mission.

  19. Conformal Ablative Thermal Protection System for Small and Large Scale Missions: Approaching TRL 6 for Planetary and Human Exploration Missions and TRL 9 for Small Probe Missions

    NASA Technical Reports Server (NTRS)

    Beck, R. A. S.; Gasch, M. J.; Milos, F. S.; Stackpoole, M. M.; Smith, B. P.; Switzer, M. R.; Venkatapathy, E.; Wilder, M. C.; Boghhozian, T.; Chavez-Garcia, J. F.

    2015-01-01

    In 2011, NASAs Aeronautics Research Mission Directorate (ARMD) funded an effort to develop an ablative thermal protection system (TPS) material that would have improved properties when compared to Phenolic Impregnated Carbon Ablator (PICA) and AVCOAT. Their goal was a conformal material, processed with a flexible reinforcement that would result in similar or better thermal characteristics and higher strain-to-failure characteristics that would allow for easier integration on flight aeroshells than then-current rigid ablative TPS materials. In 2012, NASAs Space Technology Mission Directorate (STMD) began funding the maturation of the best formulation of the game changing conformal ablator, C-PICA. Progress has been reported at IPPW over the past three years, describing C-PICA with a density and recession rates similar to PICA, but with a higher strain-to-failure which allows for direct bonding and no gap fillers, and even more important, with thermal characteristics resulting in half the temperature rise of PICA. Overall, C-PICA should be able to replace PICA with a thinner, lighter weight, less complicated design. These characteristics should be particularly attractive for use as backshell TPS on high energy planetary entry vehicles. At the end of this year, the material should be ready for missions to consider including in their design, in fact, NASAs Science Mission Directorate (SMD) is considering incentivizing the use of C-PICA in the next Discovery Proposal call. This year both scale up of the material to large (1-m) sized pieces and the design and build of small probe heatshields for flight tests will be completed. NASA, with an industry partner, will build a 1-m long manufacturing demonstration unit (MDU) with a shape based on a mid LD lifting body. In addition, in an effort to fly as you test and test as you fly, NASA, with a second industry partner, will build a small probe to test in the Interactive Heating Facility (IHF) arc jet and, using nearly the

  20. H. Julian Allen

    NASA Technical Reports Server (NTRS)

    1957-01-01

    H. Julian Allen stands beside the observation window of the 8 x 7 foot test section of the NACA Ames Unitary Plan Wind Tunnel. H. Julian Allen is best known for his 'Blunt Body Theory' of aerodynamics, a design technique for alleviating the severe re-entry heating problem which was then delaying the development of ballistic missiles. His findings revolutionized the fundamental design of ballistic missle re-entry shapes. Subsequently, applied research led to applications of the 'blunt' shape to ballistic missles and spacecraft which were intended to re-enter the Earth's atmosphere. This application led to the design of ablative heat shields that protected the Mercury, Gemini and Apollo astronauts as their space capsules re- entered the Earth's atmosphere. 'Harvey' Allen as he was called by most, was not only a brilliant scientist and aeronautical engineer but was also admired for his kindness, thoughtfulness and sense of humor. Among his many other accomplishments, Harvey Allen served as Center Director of the NASA Ames Research Center from 1965 to 1969. He died of a heart attack on January 29, 1977 at the age of 66.

  1. Screw-Retaining Allen Wrench

    NASA Technical Reports Server (NTRS)

    Granett, D.

    1985-01-01

    Steadying screws with fingers unnecessary. Crimp in uncompressed spring wire slightly protrudes from one facet of Allen wrench. Compressed spring retains Allen screw. Tool used with Allen-head screws in cramped spaces with little or no room for fingers to hold fastener while turned by wrench.

  2. The Relativistic Proton Spectrometer (RPS) for the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Mazur, J.; Friesen, L.; Lin, A.; Mabry, D.; Katz, N.; Dotan, Y.; George, J.; Blake, J. B.; Looper, M.; Redding, M.; O'Brien, T. P.; Cha, J.; Birkitt, A.; Carranza, P.; Lalic, M.; Fuentes, F.; Galvan, R.; McNab, M.

    2013-11-01

    The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ˜60 MeV to ˜2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed information for individual protons, RPS features count rates at a 1-second timescale, internal radiation dosimetry, and information about electrostatic discharge events on the RBSP spacecraft that together will provide new information about space environmental hazards in the Earth's magnetosphere.

  3. The Relativistic Proton Spectrometer (RPS) for the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; Friesen, L.; Lin, A.; Mabry, D.; Katz, N.; Dotan, Y.; George, J. S.; Blake, J. B.; Looper, M. D.; Redding, M.; O'Brien, P. P.; Cha, J.; Birkitt, A.; Carranza, P.; Lalic, M.; Fuentes, F.; Galvan, R.; McNab, M. C.

    2012-12-01

    The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ~60 MeV to ~2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed information for individual protons, RPS features count rates at a 1-second timescale, internal radiation dosimetry, and information about electrostatic discharge events on the RBSP spacecraft that together will provide new information about space environmental hazards in the Earth's magnetosphere.

  4. The Experimental Probe of Inflationary Cosmology: A Mission Concept Study for NASA's Einstein Inflation Probe

    NASA Technical Reports Server (NTRS)

    2008-01-01

    When we began our study we sought to answer five fundamental implementation questions: 1) can foregrounds be measured and subtracted to a sufficiently low level?; 2) can systematic errors be controlled?; 3) can we develop optics with sufficiently large throughput, low polarization, and frequency coverage from 30 to 300 GHz?; 4) is there a technical path to realizing the sensitivity and systematic error requirements?; and 5) what are the specific mission architecture parameters, including cost? Detailed answers to these questions are contained in this report.

  5. Design of modular probes for stratospheric balloon mission: Thermo mechanical aspects and lession learned from SORA mission.

    NASA Astrophysics Data System (ADS)

    Bettanini, Carlo; Friso, Enrico; Colombatti, Giacomo; Aboudan, Alessio; Flamini, Enrico; Pirrotta, Simone; Debei, Stefano

    Stratospheric balloon missions provide a very effective facility for testing instruments in a space-like environment with drastically lower requirements in funding and sensibly shorter timelines than common space mission. Mainly during ascent to operative altitude and parachuted de-scent the flight units face fast changing environmental conditions which may induce issues in the mechanical and thermal behavior of the equipment. A new concept modular gondola was engineered by CISAS "G.Colombo" at University of Padova,to be easily reconfigured to host scientific experiments with different power and thermal requirements thus sensibly reducing development times and costs. The gondola was mechanically designed to withstand dynamic loads related to parachute opening and ground impact and provided a 1 m x 1m x 0.3 m volume for scientific payloads which is pressure regulated with the use of relief valves and thermally controlled by main CDMU.Furthermore the whole system was able to float in case of descent in water thanks to an optmised design of the main aluminium structure and use of hermetic connections. A custom Command and Data Management Unit with hard-real-time control capabilities has been developed to manage sensors acquisition, data storage, and experiments monitoring and control. The gondola was equipped with IMU, GPS, a downward looking cam-era and a set of health check and housekeeping sensors which sample key parameters as attitude, acceleration and temperature in several parts of the structure feeding housekeeping data to the main pc in order to monitor overall system health. The unit was successfully assembled and tested at University of Padova and used in the flight of the SORA mission launched in summer 2009 from Svalbard islands to map with a penetrating radar the stratification of ice and rock above Northern Greenland. Because of unexpected wind directions the mission trajectory was several hundred kilometers southern than predicted terminating with a

  6. Science Objectives and Rationale for the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Mauk, B. H.; Fox, N. J.; Kanekal, S. G.; Kessel, R. L.; Sibeck, D. G.; Ukhorskiy, A.

    2013-11-01

    The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populations of high energy charged particles are created, vary, and evolve in space environments, and specifically within Earth's magnetically trapped radiation belts. RBSP, with a nominal launch date of August 2012, comprises two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘). The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every 2.5 months, allowing separation of spatial from temporal effects over spatial scales ranging from ˜0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the two spacecraft, measures all of the particle (electrons, ions, ion composition), fields ( E and B), and wave distributions ( d E and d B) that are needed to resolve the most critical science questions. Here we summarize the high level science objectives for the RBSP mission, provide historical background on studies of Earth and planetary radiation belts, present examples of the most compelling scientific mysteries of the radiation belts, present the mission design of the RBSP mission that targets these mysteries and objectives, present the observation and measurement requirements for the mission, and introduce the instrumentation that will deliver these measurements. This paper references and is followed by a number of companion papers that describe the details of the RBSP mission, spacecraft, and instruments.

  7. Science Objectives and Rationale for the Radiation Belt Storm Probes Mission

    NASA Technical Reports Server (NTRS)

    Mauk, B.H.; Fox, Nicola J.; Kanekal, S. G.; Kessel, R. L.; Sibek, D. G.; Ukhorskiy, A.

    2012-01-01

    The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populationsof high energy charged particles are created, vary, and evolve in space environments,and specifically within Earths magnetically trapped radiation belts. RBSP, with a nominallaunch date of August 2012, comprises two spacecraft making in situ measurements for atleast 2 years in nearly the same highly elliptical, low inclination orbits (1.1 5.8 RE, 10).The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every2.5 months, allowing separation of spatial from temporal effects over spatial scales rangingfrom 0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the twospacecraft, measures all of the particle (electrons, ions, ion composition), fields (E and B),and wave distributions (dE and dB) that are needed to resolve the most critical science questions.Here we summarize the high level science objectives for the RBSP mission, providehistorical background on studies of Earth and planetary radiation belts, present examples ofthe most compelling scientific mysteries of the radiation belts, present the mission design ofthe RBSP mission that targets these mysteries and objectives, present the observation andmeasurement requirements for the mission, and introduce the instrumentation that will deliverthese measurements. This paper references and is followed by a number of companionpapers that describe the details of the RBSP mission, spacecraft, and instruments.

  8. Seeing the corona with the solar probe plus mission: the wide-field imager for solar probe+ (WISPR)

    NASA Astrophysics Data System (ADS)

    Vourlidas, Angelos; Howard, Russell A.; Plunkett, Simon P.; Korendyke, Clarence M.; Carter, Michael T.; Thernisien, Arnaud F. R.; Chua, Damien H.; Van Duyne, Peter; Socker, Dennis G.; Linton, Mark G.; Liewer, Paulett C.; Hall, Jeffrey R.; Morrill, Jeff S.; DeJong, Eric M.; Mikic, Zoran; Rochus, Pierre L. P. M.; Bothmer, Volker; Rodman, Jens; Lamy, Philippe

    2013-09-01

    The Solar Probe Plus (SPP) mission scheduled for launch in 2018, will orbit between the Sun and Venus with diminishing perihelia reaching as close as 7 million km (9.86 solar radii) from Sun center. In addition to a suite of in-situ probes for the magnetic field, plasma, and energetic particles, SPP will be equipped with an imager. The Wide-field Imager for the Solar PRobe+ (WISPR), with a 95° radial by 58° transverse field of view, will image the fine-scale coronal structure of the corona, derive the 3D structure of the large-scale corona, and determine whether a dust-free zone exists near the Sun. Given the tight mass constrains of the mission, WISPR incorporates an efficient design of two widefield telescopes and their associated focal plane arrays based on novel large-format (2kx2k) APS CMOS detectors into the smallest heliospheric imaging package to date. The flexible control electronics allow WISPR to collect individual images at cadences up to 1 second at perihelion or sum several of them to increase the signal-to-noise during the outbound part of the orbit. The use of two telescopes minimizes the risk of dust damage which may be considerable close to the Sun. The dependency of the Thomson scattering emission of the corona on the imaging geometry dictates that WISPR will be very sensitive to the emission from plasma close to the spacecraft in contrast to the situation for imaging from Earth orbit. WISPR will be the first `local' imager providing a crucial link between the large scale corona and the in-situ measurements.

  9. Implementation Options For the Solar System Exploration Survey's "Jupiter Polar Orbiter with Probes" Mission

    NASA Astrophysics Data System (ADS)

    Spilker, T. R.

    2002-09-01

    In July of this year the National Academy of Science released a draft of its report, "New Frontiers in the Solar System: An Integrated Exploration Strategy," briefly describing the current state of solar system planetary science and the most important science objectives for the next decade (2003-2013). It includes a prioritized list of five mission concepts that might be flown as part of NASA's fledgling New Frontiers Program; each "concept" is more a list of science or measurement objectives than a full mission concept, since it does not specify implementation details in most cases. Number three on that list is the "Jupiter Polar Orbiter with Probes" ("JPOP") mission. This mission concept combines the strengths of previously described or proposed Jupiter missions into a single mission, and gains from the synergies of some of the newly-combined investigations. The primary science objectives are: 1. Determine if Jupiter has a central core 2. Determine the deep abundance of water (and other volatiles) 3. Measure Jupiter's deep winds 4. Determine the structure of Jupiter's dynamo magnetic field 5. Sample in situ Jupiter's polar magnetosphere This paper examines some of the implementation options for a JPOP mission, and gives relative advantages and disadvantages. Given the New Frontier Program's maximum cost to NASA of \\650M, plus an approx. \\120M cap on international contributions, implementing the full range of JPOP science objectives in a single New Frontiers mission may be challenging. This work was performed at the Jet Propulsion Laboratory / California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  10. The Future of NASA's Deep Space Network and Applications to Planetary Probe Missions

    NASA Technical Reports Server (NTRS)

    Deutsch, Leslie J.; Preston, Robert A.; Vrotsos, Peter

    2010-01-01

    NASA's Deep Space Network (DSN) has been an invaluable tool in the world's exploration of space. It has served the space-faring community for more than 45 years. The DSN has provided a primary communication pathway for planetary probes, either through direct- to-Earth links or through intermediate radio relays. In addition, its radiometric systems are critical to probe navigation and delivery to target. Finally, the radio link can also be used for direct scientific measurement of the target body ('radio science'). This paper will examine the special challenges in supporting planetary probe missions, the future evolution of the DSN and related spacecraft technology, the advantages and disadvantages of radio relay spacecraft, and the use of the DSN radio links for navigation and scientific measurements.

  11. EPICS: Allen-Bradley hardware reference manual

    SciTech Connect

    Nawrocki, G.

    1993-04-05

    This manual covers the following hardware: Allen-Bradley 6008 -- SV VMEbus I/O scanner; Allen-Bradley universal I/O chassis 1771-A1B, -A2B, -A3B, and -A4B; Allen-Bradley power supply module 1771-P4S; Allen-Bradley 1771-ASB remote I/O adapter module; Allen-Bradley 1771-IFE analog input module; Allen-Bradley 1771-OFE analog output module; Allen-Bradley 1771-IG(D) TTL input module; Allen-Bradley 1771-OG(d) TTL output; Allen-Bradley 1771-IQ DC selectable input module; Allen-Bradley 1771-OW contact output module; Allen-Bradley 1771-IBD DC (10--30V) input module; Allen-Bradley 1771-OBD DC (10--60V) output module; Allen-Bradley 1771-IXE thermocouple/millivolt input module; and the Allen-Bradley 2705 RediPANEL push button module.

  12. The Electric Field and Waves Instruments on the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Wygant, J. R.; Bonnell, J. W.; Goetz, K.; Ergun, R. E.; Mozer, F. S.; Bale, S. D.; Ludlam, M.; Turin, P.; Harvey, P. R.; Hochmann, R.; Harps, K.; Dalton, G.; McCauley, J.; Rachelson, W.; Gordon, D.; Donakowski, B.; Shultz, C.; Smith, C.; Diaz-Aguado, M.; Fischer, J.; Heavner, S.; Berg, P.; Malsapina, D. M.; Bolton, M. K.; Hudson, M.; Strangeway, R. J.; Baker, D. N.; Li, X.; Albert, J.; Foster, J. C.; Chaston, C. C.; Mann, I.; Donovan, E.; Cully, C. M.; Cattell, C. A.; Krasnoselskikh, V.; Kersten, K.; Brenneman, A.; Tao, J. B.

    2013-11-01

    The Electric Fields and Waves (EFW) Instruments on the two Radiation Belt Storm Probe (RBSP) spacecraft (recently renamed the Van Allen Probes) are designed to measure three dimensional quasi-static and low frequency electric fields and waves associated with the major mechanisms responsible for the acceleration of energetic charged particles in the inner magnetosphere of the Earth. For this measurement, the instrument uses two pairs of spherical double probe sensors at the ends of orthogonal centripetally deployed booms in the spin plane with tip-to-tip separations of 100 meters. The third component of the electric field is measured by two spherical sensors separated by ˜15 m, deployed at the ends of two stacer booms oppositely directed along the spin axis of the spacecraft. The instrument provides a continuous stream of measurements over the entire orbit of the low frequency electric field vector at 32 samples/s in a survey mode. This survey mode also includes measurements of spacecraft potential to provide information on thermal electron plasma variations and structure. Survey mode spectral information allows the continuous evaluation of the peak value and spectral power in electric, magnetic and density fluctuations from several Hz to 6.5 kHz. On-board cross-spectral data allows the calculation of field-aligned wave Poynting flux along the magnetic field. For higher frequency waveform information, two different programmable burst memories are used with nominal sampling rates of 512 samples/s and 16 k samples/s. The EFW burst modes provide targeted measurements over brief time intervals of 3-d electric fields, 3-d wave magnetic fields (from the EMFISIS magnetic search coil sensors), and spacecraft potential. In the burst modes all six sensor-spacecraft potential measurements are telemetered enabling interferometric timing of small-scale plasma structures. In the first burst mode, the instrument stores all or a substantial fraction of the high frequency

  13. The Solar Probe Plus Mission: Humanity's First Visit to Our Star

    NASA Astrophysics Data System (ADS)

    Fox, N. J.; Velli, M. C.; Bale, S. D.; Decker, R.; Driesman, A.; Howard, R. A.; Kasper, J. C.; Kinnison, J.; Kusterer, M.; Lario, D.; Lockwood, M. K.; McComas, D. J.; Raouafi, N. E.; Szabo, A.

    2015-11-01

    Solar Probe Plus (SPP) will be the first spacecraft to fly into the low solar corona. SPP's main science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Understanding these fundamental phenomena has been a top-priority science goal for over five decades, dating back to the 1958 Simpson Committee Report. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The mission design and the technology and engineering developments enable SPP to meet its science objectives to: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles. The SPP mission was confirmed in March 2014 and is under development as a part of NASA's Living with a Star (LWS) Program. SPP is scheduled for launch in mid-2018, and will perform 24 orbits over a 7-year nominal mission duration. Seven Venus gravity assists gradually reduce SPP's perihelion from 35 solar radii ( RS) for the first orbit to {<}10 RS for the final three orbits. In this paper we present the science, mission concept and the baseline vehicle for SPP, and examine how the mission will address the key science questions

  14. Inner Magnetosphere Imager (IMI) solar terrestrial probe class mission preliminary design study report

    NASA Technical Reports Server (NTRS)

    Hermann, M.; Johnson, L.

    1994-01-01

    For three decades, magnetospheric field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and magnetospheric conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the magnetosphere. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex magnetospheric processes, thus providing us with a clear picture of this region of space. The George C. Marshall Space Flight Center (MSFC) is responsible for defining the IMI mission which will study this region of space. NASA's Space Physics Division of the Office of Space Science placed the IMI third in its queue of Solar Terrestrial Probe missions for launch in the 1990's. A core instrument complement of three images (with the potential addition of one or more mission enhancing instruments) will fly in an elliptical, polar earth orbit with an apogee of 44,600 km and a perigee of 4,800 km. This paper will address the mission objectives, spacecraft design consideration, interim results of the MSFC concept definition study, and future plans.

  15. The Radiation Belt Storm Probes Mission: Advancing Our Understanding of the Earth's Radiation Belts

    NASA Technical Reports Server (NTRS)

    Sibeck, David; Kanekal, Shrikanth; Kessel, Ramona; Fox, Nicola; Mauk, Barry

    2012-01-01

    We describe NASA's Radiation Belt Storm Probe (RBSP) mission, whose primary science objective is to understand, ideally to the point of predictability, the dynamics of relativistic electrons and penetrating ions in the Earth's radiation belts resulting from variable solar activity. The overarching scientific questions addressed include: 1. the physical processes that produce radiation belt enhancement events, 2. the dominant mechanisms for relativistic electron loss, and 3. how the ring current and other geomagnetic processes affect radiation belt behavior. The RBSP mission comprises two spacecraft which will be launched during Fall 2012 into low inclination lapping equatorial orbits. The orbit periods are about 9 hours, with perigee altitudes and apogee radial distances of 600 km and 5.8 RE respectively. During the two-year primary mission, the spacecraft orbits precess once around the Earth and lap each other twice in each local time quadrant. The spacecraft are each equipped with identical comprehensive instrumentation packages to measure, electrons, ions and wave electric and magnetic fields. We provide an overview of the RBSP mission, onboard instrumentation and science prospects and invite scientific collaboration.

  16. A recommended entry reconstruction process for the Pioneer Venus multi-probe mission

    NASA Technical Reports Server (NTRS)

    Findlay, J. T.; Kelly, G. M.

    1978-01-01

    A method for determining the entry trajectories for the Pioneer Venus multi-probe mission is presented that utilizes earth based Doppler and onboard accelerometry as observables to provide updates for the spacecraft state and atmospheric parameters. The evolution of this method, based on error analyses and actual simulation results, is discussed. A derivative of the Viking radio science orbit determination software is recommended for the reconstruction. Telemetry data pre-processing requirements were defined. A cubic spline derivative routine is recommended to extract accelerations from the accumulated velocity decrements.

  17. A lander mission to probe subglacial water on Saturn's moon Enceladus for life

    NASA Astrophysics Data System (ADS)

    Konstantinidis, Konstantinos; Flores Martinez, Claudio L.; Dachwald, Bernd; Ohndorf, Andreas; Dykta, Paul; Bowitz, Pascal; Rudolph, Martin; Digel, Ilya; Kowalski, Julia; Voigt, Konstantin; Förstner, Roger

    2015-01-01

    The plumes discovered by the Cassini mission emanating from the south pole of Saturn's moon Enceladus and the unique chemistry found in them have fueled speculations that Enceladus may harbor life. The presumed aquiferous fractures from which the plumes emanate would make a prime target in the search for extraterrestrial life and would be more easily accessible than the moon's subglacial ocean. A lander mission that is equipped with a subsurface maneuverable ice melting probe will be most suitable to assess the existence of life on Enceladus. A lander would have to land at a safe distance away from a plume source and melt its way to the inner wall of the fracture to analyze the plume subsurface liquids before potential biosignatures are degraded or destroyed by exposure to the vacuum of space. A possible approach for the in situ detection of biosignatures in such samples can be based on the hypothesis of universal evolutionary convergence, meaning that the independent and repeated emergence of life and certain adaptive traits is wide-spread throughout the cosmos. We thus present a hypothetical evolutionary trajectory leading towards the emergence of methanogenic chemoautotrophic microorganisms as the baseline for putative biological complexity on Enceladus. To detect their presence, several instruments are proposed that may be taken aboard a future subglacial melting probe. The "Enceladus Explorer" (EnEx) project funded by the German Space Administration (DLR), aims to develop a terrestrial navigation system for a subglacial research probe and eventually test it under realistic conditions in Antarctica using the EnEx-IceMole, a novel maneuverable subsurface ice melting probe for clean sampling and in situ analysis of ice and subglacial liquids. As part of the EnEx project, an initial concept study is foreseen for a lander mission to Enceladus to deploy the IceMole near one of the active water plumes on the moon's South-Polar Terrain, where it will search for

  18. Allene ether Nazarov cyclization.

    PubMed

    Tius, Marcus A

    2014-05-01

    The ease of synthesis and the exceptional reactivity of alkoxyallenes has led to their use in a large number of highly diverse applications. This Report describes their use in various versions of the allene ether Nazarov cyclization. Following a brief introduction to the Nazarov cyclization (Section 1), the oxidative cyclization of vinyl alkoxyallenes is discussed first (Section 2). Nazarov cyclizations of α-alkoxyallenyl vinyl ketones and of α-alkoxyallenyl vinyl tertiary carbinols are covered (Section 3). The discovery and the subsequent rational design of acetals that serve as chiral auxiliaries on the allene in highly enantioselective Nazarov cyclizations is explained (Section 4). Interrupted Nazarov cyclizations of alkoxyallenes that are generated in situ from the isomerization of propargyl ethers on solid supports are discussed, including the evolution of a highly diastereoselective, chiral auxiliary controlled version of the reaction. Some applications of the methodology to natural products total synthesis have been included so as to provide the reader with benchmarks with which to judge the utility of the methodology. PMID:24196585

  19. Large Observatory For X-ray Timing (LOFT-P): A Probe-Class Mission Concept

    NASA Astrophysics Data System (ADS)

    Wilson-Hodge, Colleen A.; Ray, Paul S.; Chakrabarty, Deepto; Feroci, Marco

    2016-04-01

    LOFT-P is a mission concept for a NASA Astrophysics Probe-Class (<$1B) X-ray timing mission, based on the LOFT M-class concept originally proposed to ESA’s M3 and M4 calls. LOFT-P requires very large collecting area, high time resolution, good spectral resolution,broadband spectral coverage (2-30 keV), highly flexible scheduling, and an ability to detect and respond promptly to time-critical targets of opportunity. It addresses science questions such as: What is the equation of state of ultra dense matter? What are the effects of strong gravity on matter spiraling into black holes? It would be optimized for sub-millisecond timing of bright Galactic X-ray sources including X-ray bursters, black hole binaries, and magnetars to study phenomena at the natural timescales of neutron star surfaces and black hole event horizons and to measure mass and spin of black holes. These measurements are synergistic to imaging and high-resolution spectroscopy instruments, addressing much smaller distance scales than are possible without very long baseline X-ray interferometry, and using complementary techniques to address the geometry and dynamics of emission regions. LOFT-P would have an effective area of >6 m2, >10x that of the highly successful Rossi X-ray Timing Explorer (RXTE). A sky monitor (~2-50 keV) acts as a trigger for pointed observations, providing high duty cycle, high time resolution monitoring of the X-ray sky with ~20 times the sensitivity of the RXTE All-Sky Monitor, enabling multi-wavelength and multi-messenger studies. A probe-class mission concept would employ lightweight collimator technology and large-area solid-state detectors, segmented into pixels or strips, technologies which have been recently greatly advanced during the ESA M-3 Phase A study of LOFT. Given the large community interested in LOFT (>800 supporters), the scientific productivity of this mission is expected to be very high, similar to or greater than RXTE (~2000 refereed publications.) In

  20. Hera - an ESA M-class Saturn Entry Probe Mission Proposal

    NASA Astrophysics Data System (ADS)

    Atkinson, D. H.; Mousis, O.; Spilker, T. R.; Venkatapathy, E.; Poncy, J.; Coustenis, A.; Reh, K. R.

    2015-12-01

    A fundamental goal of solar system exploration is to understand the origin of the solar system, the initial stages, conditions, and processes by which the solar system formed, how the formation process was initiated, and the nature of the interstellar seed material from which the solar system was born. Key to understanding solar system formation and subsequent dynamical and chemical evolution is the origin and evolution of the giant planets and their atmospheres. Additionally, the atmospheres of the giant planets serve as laboratories to better understand the atmospheric chemistries, dynamics, processes, and climates on all planets in the solar system including Earth, offer a context and provide a ground truth for exoplanets and exoplanetary systems, and have long been thought to play a critical role in the development of potentially habitable planetary systems. Remote sensing observations are limited when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the value of in situ measurements is provided by measurements of Jupiter's noble gas abundances and helium mixing ratio by the Galileo probe. In situ measurements provide direct access to atmospheric regions that are beyond the reach of remote sensing, enabling the dynamical, chemical and aerosol-forming processes at work from the thermosphere to the troposphere below the cloud decks to be studied. Studies for a newly proposed Saturn atmospheric entry probe mission named Hera is being prepared for the upcoming European Space Agency Medium Class (M5) mission announcement of opportunity. A solar powered mission, Hera will take approximately 8 years to reach Saturn and will carry instruments to measure the composition, structure, and dynamics of Saturn's atmosphere. In the context of giant planet science provided by the Galileo, Juno, and Cassini missions to Jupiter and Saturn, the Hera Saturn probe will provide critical measurements of composition

  1. Applied Doppler Imaging: Can The Magnetic Activity Of IM Pegasi Affect The Gravity Probe B Mission?

    NASA Astrophysics Data System (ADS)

    Marsden, S. C.; Berdyugina, S. V.

    2006-08-01

    IM Pegasi is a single-lined spectroscopic RS CVn binary, with the primary being a rapidly-rotating (vsini = 27 km/s) early-K giant. Magnetic activity of the primary is evident as dark spot features covering 15% or more of the stellar surface. Since the system is bright in both optical and radio bands, IM Pegasi was chosen as a guide star for the Gravity Probe B (GP-B) satellite mission. The mission is designed to verify two predictions of Einstein's theory of general relativity, the geodetic effect and "frame-dragging", based on measurements of mean gyroscope drift with respect to the optical centroid of IM Pegasi. The requested standard error of 0.5 milliarcseconds/year implies that even small contributions to the shift of the optical centroid of IM Pegasi due to surface magnetic activity must be determined. In support of the GP-B mission we are undertaking an intensive Doppler imaging survey of the primary component of IM Pegasi to determine the effect of spot features on the optical centroid of IM Pegasi. We present an overview of our role in GP-B and report initial results from this support project, including the first magnetic maps of the IM Pegasi primary, created using Least-Squares Deconvolution and Zeeman Doppler Imaging.

  2. Rapid enhancement of low energy (<100 eV) ion flux in response to interplanetary shocks based on two Van Allen Probes case studies: Implications for source regions and heating mechanisms

    DOE PAGESBeta

    Yue, Chao; Li, Wen; Reeves, Geoffrey D.; Nishimura, Yukitoshi; Zong, Qiugang; Ma, Qianli; Bortnik, Jacob; Thorne, Richard M.; Spence, Harlan E.; Kletzing, Craig A.; et al

    2016-07-15

    Interactions between interplanetary (IP) shocks and the Earth's magnetosphere manifest many important space physics phenomena including low-energy ion flux enhancements and particle acceleration. In order to investigate the mechanisms driving shock-induced enhancement of low-energy ion flux, we have examined two IP shock events that occurred when the Van Allen Probes were located near the equator while ionospheric and ground observations were available around the spacecraft footprints. We have found that, associated with the shock arrival, electromagnetic fields intensified, and low-energy ion fluxes, including H+, He+, and O+, were enhanced dramatically in both the parallel and perpendicular directions. During the 2more » October 2013 shock event, both parallel and perpendicular flux enhancements lasted more than 20 min with larger fluxes observed in the perpendicular direction. In contrast, for the 15 March 2013 shock event, the low-energy perpendicular ion fluxes increased only in the first 5 min during an impulse of electric field, while the parallel flux enhancement lasted more than 30 min. In addition, ionospheric outflows were observed after shock arrivals. From a simple particle motion calculation, we found that the rapid response of low-energy ions is due to drifts of plasmaspheric population by the enhanced electric field. Furthermore, the fast acceleration in the perpendicular direction cannot solely be explained by E × B drift but betatron acceleration also plays a role. Adiabatic acceleration may also explain the fast response of the enhanced parallel ion fluxes, while ion outflows may contribute to the enhanced parallel fluxes that last longer than the perpendicular fluxes.« less

  3. Large Observatory for X-ray Timing (LOFT-P): A Probe-Class Mission Concept Study

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.; Ray, P. S.; Chakrabarty, D.; Feroci, M.; Jenke, Peter; Griffith, C.; Zane, S.; Winter, B.; Brandt, S.; Hernamdez, M.; Hickman, R.; Hopkins, R.; Garcia, J.; Chapman, J.; Schnell, A.; Becker, C.; Dominguez, A.; Ingram, L.; Gangl, B.; Carson, B.

    2016-01-01

    LOFT-P is a mission concept for a NASA Astrophysics Probe-Class (less than $1B) X-ray timing mission, based on the LOFT M-class concept originally proposed to ESA's M3 and M4 calls. LOFT-P requires very large collecting area, high time resolution, good spectral resolution, broadband spectral coverage (2-30 keV), highly flexible scheduling, and an ability to detect and respond promptly to time-critical targets of opportunity. Many of LOFTP's targets are bright, rapidly varying sources, so these measurements are synergistic to imaging and high-resolution spectroscopy instruments, addressing much smaller distance scales than are possible without very long baseline X-ray interferometry, and using complementary techniques to address the geometry and dynamics of emission regions. LOFT-P was presented as an example mission to the head of NASA's Astrophysics Division, to demonstrate the strong community support for creation of a probe-class, for missions costing between $500M and $1B. We submitted a white paper4 in response to NASA PhysPAG's call for white papers: Probe-class Mission Concepts, describing LOFT-P science and a simple extrapolation from the ESA study costs. The next step for probe-class missions will be input into the NASA Astrophysics Decadal Survey to encourage the creation of a probe-class opportunity. We report on a 2016 study by MSFC's Advanced Concepts Office of LOFT-P, a US-led probe-class LOFT concept.

  4. Long-life mission reliability for outer planet atmospheric entry probes

    NASA Technical Reports Server (NTRS)

    Mccall, M. T.; Rouch, L.; Maycock, J. N.

    1976-01-01

    The results of a literature analysis on the effects of prolonged exposure to deep space environment on the properties of outer planet atmospheric entry probe components are presented. Materials considered included elastomers and plastics, pyrotechnic devices, thermal control components, metal springs and electronic components. The rates of degradation of each component were determined and extrapolation techniques were used to predict the effects of exposure for up to eight years to deep space. Pyrotechnic devices were aged under accelerated conditions to an equivalent of eight years in space and functionally tested. Results of the literature analysis of the selected components and testing of the devices indicated that no severe degradation should be expected during an eight year space mission.

  5. The Maneuver Planning Process for the Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Andrews, Stephen F.; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) mission utilized a strategy combining highly eccentric phasing loops with a lunar gravity assist to provide a zero-cost insertion into a Lissajous orbit about the Sun-Earth/Moon L2 point. Maneuvers were executed at the phasing loop perigees to correct for launch vehicle errors and to target the lunar gravity assist so that a suitable orbit at L2 was achieved. This paper will discuss the maneuver planning process for designing, verifying, and executing MAP's maneuvers. This paper will also describe how commercial off-the-shelf (COTS) tools were used to execute these tasks and produce a command sequence ready for upload to the spacecraft. These COTS tools included Satellite Tool Kit, MATLAB, and Matrix-X.

  6. Orbiter description document for Jupiter Orbiter Probe 1981/1982 Mission

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The Jupiter Orbiter as it is presently understood is documented. Because the Jupiter Orbiter Probe 1981/1982 (JOP 81/82) Project will be severely cost constrained, the Orbiter design and capabilities described herein are not subject to major change or modification as a result of instrument selection. The JOP science payload should conform to this defined capability and the specified interfaces. A description and discussion of any science instrument complement is excluded, except the imaging science subsystem and the radio science capability which are provided by the project as Orbiter facilities. The environmental design requirements and the mission operations description are studied. This document has been prepared specifically for the JOP Announcement of Opportunity proposal preparation package and describes the Jupiter Orbiter in sufficient detail to allow the science community to propose scientific instrumentation consistent with its capabilities and limitations.

  7. Application of Monte-Carlo Analyses for the Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Rohrbaugh, David; Schiff, Conrad; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The Microwave Anisotropy Probe (MAP) is the third launch in the National Aeronautics and Space Administration's (NASA's) a Medium Class Explorers (MIDEX) program. MAP will measure, in greater detail, the cosmic microwave background radiation from an orbit about the Sun-Earth-Moon L2 Lagrangian point. Maneuvers will be required to transition MAP from it's initial highly elliptical orbit to a lunar encounter which will provide the remaining energy to send MAP out to a lissajous orbit about L2. Monte-Carlo analysis methods were used to evaluate the potential maneuver error sources and determine their effect of the fixed MAP propellant budget. This paper will discuss the results of the analyses on three separate phases of the MAP mission - recovering from launch vehicle errors, responding to phasing loop maneuver errors, and evaluating the effect of maneuver execution errors and orbit determination errors on stationkeeping maneuvers at L2.

  8. A Model Space Mission to probe Einstein's Equivalence Principle - The STE-QUEST Study

    NASA Astrophysics Data System (ADS)

    Heske, Astrid; Cacciapuoti, Luigi; Gehler, Martin

    Understanding General Relativity at all scales requires, in particular, understanding gravity at quantum level. To attempt this, tests of the most prominent aspect of General Relativity, the Einstein Equivalence Principle, can be performed with the next generation of atomic quantum sensors to significantly improved accuracy. To exploit the ultimate limits of atomic sensors a dedicated space platform is needed; the advantages space offers are, among others, unperturbed free-fall conditions, longer interaction times per measurement and large variations in velocity and gravitational field. In the frame of the third medium class launch opportunity of ESA's Cosmic Vision 2015 - 2025 programme a study was conducted - STE-QUEST (Space-Time Explorer and QUantum Equivalence principle Test), one of the candidates for a medium class mission - and the feasibility of such a mission assessed. The spacecraft would carry two instruments probing the different aspects of the Einstein Equivalence Principle: begin{enumerate} A dual species ( (87) Rb and (85) Rb) atom interferometer to probe the universality of propagation of matter waves. A high-performance time and frequency link dedicated to comparison of atomic clocks on ground. The specific primary science objectives for STE-QUEST are: begin{enumerate} Universality of propagation of matter waves test begin{itemize} Test of the universality of free fall of matter waves to an uncertainty of the Eötvös ratio lower than 2*10 (-15) . Gravitational redshift tests begin{itemize} Sun gravitational red-shift measurement to a fractional uncertainty of 2*10 (-6) , with an ultimate goal of 5*10 (-7) . Moon gravitational red-shift measurement to a fractional uncertainty of 4*10 (-4) , with an ultimate goal of 9*10 (-5) . Such a measurement has never been attempted before. The availability of an atomic clock on-board the spacecraft (optional) would additionally allow testing the Earth gravitational red-shift measurement to a fractional

  9. Applied Doppler Imaging: Can Magnetic Activity of IM Pegasi Affect the Gravity Probe B Mission?

    NASA Astrophysics Data System (ADS)

    Berdyugina, S. V.; Marsden, S. C.

    2006-12-01

    IM Peg is a single-lined, spectroscopic RS CVn binary, with a rapidly rotating (v sin i=27 km/s), early K-type, giant primary. Magnetic activity of the primary is indicated by dark spots covering > 15% of the surface. The system is bright in both optical and radio, and was chosen as a guide star for the Gravity Probe B (GP-B) satellite mission. The goal of GP-B is to verify two predictions of Einstein's theory of general relativity (geodetic effect and ``frame dragging''), based on measurements of mean gyroscopic drift with respect to the optical centroid of IM Peg. The requested precision of 0.5×10-3 arcsec/yr implies that even small shifts of the optical centroid of IM Peg due to surface magnetic activity must be determined. In support of the GP-B mission, we are undertaking an intensive Doppler imaging survey of the primary component of IM Peg, to determine the effect of spot features on its optical centroid. We present an overview of our work for GP-B, and report initial results from this support project, including the first magnetic maps of the IM~Peg primary, created using Least-Squares Deconvolution and Zeeman Doppler Imaging.

  10. A New Vision of Science and Strategy for an Interstellar Probe Mission

    NASA Astrophysics Data System (ADS)

    Gruntman, M.; McNutt, R. L.; Krimigis, S. M.; Wimmer-Schweingruber, R. F.; Gold, R. E.

    2011-12-01

    The recent in-situ and remote observations from the Voyager Interstellar Mission (VIM), the Interstellar Boundary Explorer (IBEX), and Ion and Neutral Camera (INCA) Cassini have revealed the interaction of the heliosphere with the very local interstellar medium (VLISM) to be much more complex than described by our present day concepts. These discoveries call for a major revision of the strategy for the Interstellar Probe, a mission to explore the interstellar medium surrounding the Solar System. Voyager 1 and Voyager 2 continue to reveal unanticipated flow patterns and significant fluxes of energetic particles in the heliosheath (beyond the solar wind termination shock) while pointing to a more remote location for the modulation region and source of the anomalous cosmic rays (ACRs). Remarkably, Voyager 1 has been reporting near-zero plasma flows (10's of km/s) beyond 115 AU for over the past year. One implication of this flow stagnation is that Voyager is already in a "transition layer" that could lead to the interstellar plasma. Consequently an Interstellar Probe Mission may "punch out" into the deflected interstellar plasma flow at a much smaller distance than previous models had predicted. Global imaging observations by IBEX and INCA of energetic neutral atoms (ENAs) originating from the interaction region(s) of the solar wind and the VLISM show unexpected structure and possible time dependence on a variety of scales. In addition to the general "glow" of the sky in ENAs, IBEX revealed a relatively narrow "ribbon" of enhanced atomic hydrogen emission from ~200 eV to ~6 keV. The neutrals from both the glow and ribbon are also characterized by non-thermal distribution functions. In addition, INCA on Cassini sees a "belt" of emission in ENAs, broader than the ribbon and tilted significantly away from it, at even higher energies (10s of keV). This evidence supports the idea that the bulk of the energy density in the heliosheath plasma resides in a non

  11. Development of Feedhorn-Coupled Multichroic Polarimeters for the Inflation Probe Mission

    NASA Astrophysics Data System (ADS)

    McMahon, Jeff

    This proposal seeks support for the development of millimeter-wavelength multichroic polarimeters optimized for detecting Cosmic Microwave Background (CMB) polarization signals with a future NASA Inflation Probe Mission. The technologies developed under this proposal would also have applications in future submillimeter astrophysics satellite missions. The proposed technology would increase the overall experimental sensitivity of an Inflation Probe Mission over that achievable by single-frequency pixels, making efficient use of available diffraction-limited focal plane area while maintaining unmatched control over systematics through the use of corrugated feedhorns. The sensitivity, multi-frequency coverage, and control of detector systematics offered by this technology on the Inflation Probe Mission would provide the definitive measurement of CMB polarization and foreground sources. These data would unambiguously detect or rule out all models of Grand Unified Theory (GUT) scale inflation, provide a precise measurement of the sum of the neutrino masses, and enable a wide variety of astrophysical and additional cosmological measurements. Control of systematics and foregrounds are paramount for a successful detection of the faint inflationary signal. Corrugated feedhorns are the gold standard for producing symmetric beams with low cross-polarization. Using ring-loaded slots, they can be designed to exceed one octave in bandwidth, allowing for multiple bands using a single feed. For the optimal characterization and control of foregrounds, approximately 10 bands are needed over a frequency range roughly spanning 40-300 GHz. Our plan is to develop a scalable multichroic architecture with four frequency bands within an octave of bandwidth, which we will then scale to three different frequency ranges, for a total of 12 bands with band centers on a logarithmic scale ranging from 40-288 GHz. At the key frequencies for CMB polarization (100-150 GHz) our proposed detectors

  12. Survey of the frequency dependent latitudinal distribution of the fast magnetosonic wave mode from Van Allen Probes Electric and Magnetic Field Instrument and Integrated Science waveform receiver plasma wave analysis

    NASA Astrophysics Data System (ADS)

    Boardsen, Scott A.; Hospodarsky, George B.; Kletzing, Craig A.; Engebretson, Mark J.; Pfaff, Robert F.; Wygant, John R.; Kurth, William S.; Averkamp, Terrance F.; Bounds, Scott R.; Green, Jim L.; De Pascuale, Sebastian

    2016-04-01

    We present a statistical survey of the latitudinal structure of the fast magnetosonic wave mode detected by the Van Allen Probes spanning the time interval of 21 September 2012 to 1 August 2014. We show that statistically, the latitudinal occurrence of the wave frequency (f) normalized by the local proton cyclotron frequency (fcP) has a distinct funnel-shaped appearance in latitude about the magnetic equator similar to that found in case studies. By comparing the observed E/B ratios with the model E/B ratio, using the observed plasma density and background magnetic field magnitude as input to the model E/B ratio, we show that this mode is consistent with the extra-ordinary (whistler) mode at wave normal angles (θk) near 90°. Performing polarization analysis on synthetic waveforms composed from a superposition of extra-ordinary mode plane waves with θk randomly chosen between 87 and 90°, we show that the uncertainty in the derived wave normal is substantially broadened, with a tail extending down to θk of 60°, suggesting that another approach is necessary to estimate the true distribution of θk. We find that the histograms of the synthetically derived ellipticities and θk are consistent with the observations of ellipticities and θk derived using polarization analysis. We make estimates of the median equatorial θk by comparing observed and model ray tracing frequency-dependent probability occurrence with latitude and give preliminary frequency dependent estimates of the equatorial θk distribution around noon and 4 RE, with the median of ~4 to 7° from 90° at f/fcP = 2 and dropping to ~0.5° from 90° at f/fcP = 30. The occurrence of waves in this mode peaks around noon near the equator at all radial distances, and we find that the overall intensity of these waves increases with AE*, similar to findings of other studies.

  13. Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Bower, Geoffrey

    2007-05-01

    The Allen Telescope Array (ATA) is a pioneering centimeter-wavelength radio telescope that will produce science that cannot be done with any other instrument. The ATA is the first radio telescope designed for commensal observing; it will undertake the most comprehensive and sensitive SETI surveys ever done as well as the deepest and largest area continuum and spectroscopic surveys. Science operations will commence this year with a 42-element array. The ATA will ultimately comprise 350 6-meter dishes at Hat Creek in California, and will make possible large, deep radio surveys that were not previously feasible. The telescope incorporates many new design features including hydroformed antenna surfaces, a log-periodic feed covering the entire range of frequencies from 500 MHz to 11.2 GHz, low noise, wide-band amplifiers with a flat response over the entire band. The full array has the sensitivity of the Very Large Array but with a survey capability that is greater by an order of magnitude due to the wide field of view of the 6-meter dishes. Even with 42 elements, the ATA will be one of the most powerful radio survey telescopes. Science goals include the Five GHz sky survey (FiGSS) to match the 1.4-GHz NRAO VLA Sky Survey (NVSS) and the Sloan Digital Sky Survey within the first year of operation with the 42 element array, and a deep all-sky survey of extragalactic hydrogen to investigate galaxy evolution and intergalactic gas accretion. Transient and variable source surveys, pulsar science, spectroscopy of new molecular species in the galaxy, large-scale mapping of galactic magnetic filaments, and wide-field imaging of comets and other solar system objects are among the other key science objectives of the ATA. SETI surveys will reach sufficient sensitivity to detect an Arecibo planetary radar from 1,000,000 stars to distances of 300 pc.

  14. Utilizing Mars Global Reference Atmospheric Model (Mars-GRAM 2005) to Evaluate Entry Probe Mission Sites

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.

    2008-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM 2005) is an engineering-level atmospheric model widely used for diverse mission applications. An overview is presented of Mars-GRAM 2005 and its new features. The "auxiliary profile" option is one new feature of Mars-GRAM 2005. This option uses an input file of temperature and density versus altitude to replace the mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. Any source of data or alternate model output can be used to generate an auxiliary profile. Auxiliary profiles for this study were produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5) model) and a global Thermal Emission Spectrometer (TES) database. The global TES database has been specifically generated for purposes of making Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components, averaged over 5-by-5 degree latitude-longitude bins and 15 degree Ls bins, for each of three Mars years of TES nadir data. The Mars Science Laboratory (MSL) sites are used as a sample of how Mars-GRAM' could be a valuable tool for planning of future Mars entry probe missions. Results are presented using auxiliary profiles produced from the mesoscale model output and TES observed data for candidate MSL landing sites. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

  15. The Engineering Radiation Monitor for the Radiation Belt Storm Probes Mission

    NASA Astrophysics Data System (ADS)

    Goldsten, J. O.; Maurer, R. H.; Peplowski, P. N.; Holmes-Siedle, A. G.; Herrmann, C. C.; Mauk, B. H.

    2013-11-01

    An Engineering Radiation Monitor (ERM) has been developed as a supplementary spacecraft subsystem for NASA's Radiation Belt Storm Probes (RBSP) mission. The ERM will monitor total dose and deep dielectric charging at each RBSP spacecraft in real time. Configured to take the place of spacecraft balance mass, the ERM contains an array of eight dosimeters and two buried conductive plates. The dosimeters are mounted under covers of varying shielding thickness to obtain a dose-depth curve and characterize the electron and proton contributions to total dose. A 3-min readout cadence coupled with an initial sensitivity of ˜0.01 krad should enable dynamic measurements of dose rate throughout the 9-hr RBSP orbit. The dosimeters are Radiation-sensing Field Effect Transistors (RadFETs) and operate at zero bias to preserve their response even when powered off. The range of the RadFETs extends above 1000 krad to avoid saturation over the expected duration of the mission. Two large-area (˜10 cm2) charge monitor plates set behind different thickness covers will measure the dynamic currents of weakly-penetrating electrons that can be potentially hazardous to sensitive electronic components within the spacecraft. The charge monitors can handle large events without saturating (˜3000 fA/cm2) and provide sufficient sensitivity (˜0.1 fA/cm2) to gauge quiescent conditions. High time-resolution (5 s) monitoring allows detection of rapid changes in flux and enables correlation of spacecraft anomalies with local space weather conditions. Although primarily intended as an engineering subsystem to monitor spacecraft radiation levels, real-time data from the ERM may also prove useful or interesting to a larger community.

  16. Starspots and relativity: Applied Doppler imaging for the Gravity Probe B mission

    NASA Astrophysics Data System (ADS)

    Marsden, S. C.; Berdyugina, S. V.; Donati, J.-F.; Eaton, J. A.; Williamson, M. H.

    2007-12-01

    We present Doppler images and surface differential rotation measurements for the primary of the RS CVn binary IM Pegasi, the guide star for the Gravity Probe B experiment. The data used is a subset of that taken during optical support of the mission and was obtained almost nightly over a near three year period from the Automatic Spectroscopic Telescope operated by Tennessee State University. Using the technique of least-squares deconvolution to increase the signal-to-noise ratio of the data, we have reconstructed 31 maximum entropy Doppler images of the star. The images show that the spot features are relatively stable for over a year (and possibly longer) with both a polar spot and lower latitude features. The most intense features are located on the side facing the secondary. In addition, we have incorporated a solar-like differential rotation law into the imaging process to determine the level of surface differential rotation for IM Peg for 22 epochs. A weighted least-squares average of the measurements gives a surface shear of 0.0142 ± 0.0007 rad/d, meaning that the equator takes ˜440 ± 20 days to lap the poles. Although the level of surface differential rotation was shown to vary over the period of the observations, this may indicate an underestimate in the errors of the method rather than any temporal evolution in the differential rotation. Movies are available via http://www.aip.de/AN/movies

  17. Material Development of Faraday Cup Grids for the Solar Probe Plus Mission

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.; Wright, K. H.; Cirtain, J. W.; Lee, R.; Kasper, J. C.

    2011-01-01

    The Solar Probe Plus mission will launch a spacecraft to the Sun to study it's outer atmosphere. One of the instruments on board will be a Faraday Cup (FC) sensor. The FC will determine solar wind properties by measuring the current produced by ions striking a metal collector plate. It will be directly exposed to the Sun and will be subject to the temperature and radiation environment that exist within 10 solar radii. Conducting grids within the FC are biased up to 10 kV and are used to selectively transmit particles based on their energy to charge ratio. We report on the development of SiC grids. Tests were done on nitrogen-doped SiC starting disks obtained from several vendors, including annealing under vacuum at 1400 C and measurement of their electrical properties. SiC grids were manufactured using a photolithographic and plasma-etching process. The grids were incorporated into a prototype FC and tested in a simulated solar wind chamber. The energy cutoffs were measured for both proton and electron fluxes and met the anticipated sensor requirements.

  18. Timing system design and tests for the Gravity Probe B relativity mission

    NASA Astrophysics Data System (ADS)

    Li, J.; Keiser, G. M.; Lockhart, J. M.; Ohshima, Y.; Shestople, P.

    2015-11-01

    In this paper, we discuss the timing system design and tests for the NASA/Stanford Gravity Probe B (GP-B) relativity mission. The primary clock of GP-B, called the 16fo clock, was an oven-controlled crystal oscillator that produced a 16.368 MHz master frequency3. The 16fo clock and the 10 Hz data strobe, which was divided down from the 16fo clock, provided clock signals to all GP-B components and synchronized the data collection, transmission, and processing. The sampled data of science signals were stamped with the vehicle time, a counter of the 10 Hz data strobe. The time latency between the time of data sampling and the stamped vehicle time was compensated in the ground data processing. Two redundant global positioning system receivers onboard the GP-B satellite supplied an external reference for time transfer between the vehicle time and coordinated universal time (UTC), and the time conversion was established in the ground preprocessing of the telemetry timing data. The space flight operation showed that the error of time conversion between the vehicle time and UTC was less than 2 μs. Considering that the constant timing offsets were compensated in the ground processing of the GP-B science data, the time latency between the effective sampling time of GP-B science signals and the stamped vehicle time was verified to within 1 ms in the ground tests.

  19. A Study of the Structure of the Source Region of the Solar Wind in Support of a Solar Probe Mission

    NASA Technical Reports Server (NTRS)

    Habbal , Shadia R.

    1998-01-01

    Despite the richness of the information about the physical properties and the structure of the solar wind provided by the Ulysses and SOHO observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow solar wind, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the solar atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the solar wind, is the corona between 1 and 30 R(sub s). A Solar Probe mission offers an unprecedented opportunity to explore this frontier. The uniqueness of this mission stems from its trajectory in a plane perpendicular to the ecliptic which reaches within 9 R(sub s), of the solar surface over the poles and 3 - 9 R(sub s), at the equator. With a complement of simultaneous in situ and remote sensing observations, this mission is destined to have a significant impact on our understanding of the fundamental processes that heat the corona and drive the solar wind. The Solar Probe should be able to detect remnants and signatures of the processes which heat the corona and accelerate the solar wind. The primary objective of this proposal was to explore the structure of the different source regions of the solar wind through complementary observational and theoretical studies in support of a Solar Probe mission.

  20. Obituary: James Alfred Van Allen, 1914-2006

    NASA Astrophysics Data System (ADS)

    Ludwig, George H.; McIlwain, Carl Edwin

    2006-12-01

    James Alfred Van Allen, world-renowned space scientist, died 9 August 2006 at the age of ninety-one. He succumbed to heart failure after a ten-week period of declining health. Van Allen served for his entire sixty-seven-year professional career as an amazingly productive researcher, space science spokesman, inspired teacher, and valued colleague. The realization by him and his associates that charged particles are trapped by the Earth's magnetic field began a whole new field of research, magnetospheric physics. Following that initial discovery, he and his associates quickly extended their observations, first to the inner planets, and then to the rest of the planets and beyond. During his tenure at Iowa, he and his group flew instruments on more than sixty successful Earth satellites and planetary spacecraft, including the first missions to the planets Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Van Allen's lifetime publication list numbers more than 275, of which many are widely-cited, seminal papers. He was the sole author of more than 125 of those papers. Beyond the research laboratory, Van Allen worked energetically throughout his career in establishing space research as a new branch of human inquiry. He was among the most sought-after as a committee member and adviser, working at the highest levels of government, including the White House and Congress, and at all levels of the national and international research establishments. Many presentations in the non-scientific arena helped to bring the exciting discoveries and challenges of space research to the attention of the general public. James Van Allen (Van to his many friends and colleagues) was born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, the second of four sons of Alfred Morris Van Allen and Alma Olney Van Allen. After high school in Mount Pleasant, he entered Iowa Wesleyan College, majoring in physics and graduating summa cum laude. While there, he was introduced to geophysics

  1. Impact of science objectives and requirements on probe mission and system design

    NASA Technical Reports Server (NTRS)

    Ledbetter, K. W.

    1974-01-01

    Problem areas in probe science technology are discussed that require a solution before probe systems can actually be designed. Considered are the effects of the model atmospheres on probe design; secondly, the effects of implementing the requirements to locate and measure the clouds and, trade-offs between descent sampling and measurement criteria as they affect probe system design.

  2. Feasibility Study of Interstellar Missions Using Laser Sail Probes Ranging in Size from the Nano to the Macro

    NASA Technical Reports Server (NTRS)

    Malroy, Eric T.

    2010-01-01

    This paper presents the analysis examining the feasibility of interstellar travel using laser sail probes ranging in size from the nano to the macro. The relativistic differential equations of motion for a laser sail are set up and solved using the Pasic Method. The limitations of the analysis are presented and discussed. The requirements for the laser system are examined, including the thermal analysis of the laser sails. Black holes, plasma fields, atmospheric collisions and sun light are several methods discussed to enable the deceleration of the interstellar probe. A number of novel mission scenarios are presented including the embryonic transport of plant life as a precursor to the arrival of space colonies

  3. The Maneuver Planning Process for the Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Andrews, Stephen; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) was successfully launched from Kennedy Space Center's Eastern Range on June 30, 2001. MAP will measure the cosmic microwave background as a follow up to NASA's Cosmic Background Explorer (COBE) mission from the early 1990's. MAP will take advantage of its mission orbit about the Sun-Earth/Moon L2 Lagrangian point to produce results with higher resolution, sensitivity, and accuracy than COBE. A strategy comprising highly eccentric phasing loops with a lunar gravity assist was utilized to provide a zero-cost insertion into a lissajous orbit about L2. Maneuvers were executed at the phasing loop perigees to correct for launch vehicle errors and to target the lunar gravity assist so that a suitable orbit at L2 was achieved. This paper will discuss the maneuver planning process for designing, verifying, and executing MAP's maneuvers. A discussion of the tools and how they interacted will also be included. The maneuver planning process was iterative and crossed several disciplines, including trajectory design, attitude control, propulsion, power, thermal, communications, and ground planning. Several commercial, off-the-shelf (COTS) packages were used to design the maneuvers. STK/Astrogator was used as the trajectory design tool. All maneuvers were designed in Astrogator to ensure that the Moon was met at the correct time and orientation to provide the energy needed to achieve an orbit about L2. The Mathworks Matlab product was used to develop a tool for generating command quaternions. The command quaternion table (CQT) was used to drive the attitude during the perigee maneuvers. The MatrixX toolset, originally written by Integrated Systems, Inc., now distributed by Mathworks, was used to create HiFi, a high fidelity simulator of the MAP attitude control system. HiFi was used to test the CQT and to make sure that all attitude requirements were met during the maneuver. In addition, all ACS data plotting and output were generated in

  4. Allene Functionalization via Bicyclic Methylene Aziridines

    PubMed Central

    Boralsky, Luke A.; Marston, Dagmara; Grigg, R. David; Hershberger, John C.; Schomaker, Jennifer M.

    2011-01-01

    The oxidative functionalization of olefins is a common method for the formation of vicinal carbon-heteroatom bonds. However, oxidative methods to transform allenes into synthetic motifs containing three contiguous carbon-heteroatom bonds are much less developed. This paper describes the use of bicyclic methylene aziridines (MAs), prepared via intramolecular allene aziridination, as scaffolds for functionalization of all three allene carbons. PMID:21438516

  5. Apollo 14 mission: Failure to achieve docking probe capture latch engagement

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Six docking attempts were required in order to successfully achieve capture latch engagement during the transposition and docking phase following translunar injection. After docking, the probe and drogue were examined by the crew. Probe operation appeared normal and radial marks were noted on the drogue. During all subsequent operations, the probe operated properly.

  6. Project Icarus: Preliminary Thoughts on the Selection of Probes and Instruments for an Icarus-style Interstellar Mission

    NASA Astrophysics Data System (ADS)

    Crawford, Ian A.

    2016-06-01

    In this paper we outline the range of probes and scientific instruments that will be required in order for Icarus to fulfill its scientific mission of exploring a nearby star, its attendant planetary system, and the intervening interstellar medium. Based on this preliminary analysis, we estimate that the minimum total Icarus scientific payload mass (i.e. the mass of probes and instruments which must be decelerated to rest in the target system to enable a meaningful programme of scientific investigation) will be in the region of 100 tonnes. Of this, approximately 10 tonnes would be allocated for cruise-phase science instruments, and about 35 tonnes (i.e. the average of estimated lower and upper limits of 28 and 41 tonnes) would be contributed by the intra-system science payload itself (i.e. the dry mass of the stellar and planetary probes and their instruments). The remaining ~55 tonnes is allocated for the sub-probe intra-system propulsion requirements (crudely estimated from current Solar System missions; detailed modelling of sub-probe propulsion systems will be needed to refine this figure). The overall mass contributed by the science payload to the total that must be decelerated from the interstellar cruise velocity will be considerably more than 100 tonnes, however, as allowance must be made for the payload structural and infrastructural elements required to support, deploy, and communicate with the science probes and instruments. Based on the earlier Daedalus study, we estimate another factor of two to allow for these components. Pending the outcome of more detailed studies, it therefore appears that an overall science-related payload mass of ~200 tonnes will be required. This paper is a submission of the Project Icarus Study Group.

  7. Analysis of the Phoenix Mission's Thermal and Electrical Conductivity Probe (TECP) Relative Humidity Data

    NASA Astrophysics Data System (ADS)

    Fischer, E.; Martinez, G.; Renno, N. O.; Tamppari, L.; Zent, A.

    2015-12-01

    With funding from NASA's Mars Data Analysis Program, we plan to enhance the scientific return of the Phoenix mission by producing and archiving high-level relative humidity (RH) data from the measurements made by the Thermal and Electrical Conductivity Probe (TECP). Values of temperature and RH covered in the pre-flight calibration [1] overlap only partially with the environmental conditions found at the Phoenix landing site [2,3]. In particular, there is no overlap at dawn, when temperatures are the lowest and the expected RH is the highest [4] and in the middle of the day, when temperatures are relatively high and the expected RH is very low [5]. Here we plan to produce high-level RH data by calibrating an Engineering Model of the TECP in the Michigan Mars Environmental Chamber (MMEC). The MMEC is capable of simulating the entire range of environmental conditions found at the Phoenix landing site. The MMEC is a cylindrical chamber with internal diameter of 64 cm and length of 160 cm. It is capable of simulating temperatures ranging from 145 to 500 K, CO2 pressures ranging from 10 to 105 Pa, and relative humidity ranging from nearly 0 to 100% [6]. The analysis of high-level RH data has the potential to shed light on the formation of liquid brines at Mars' polar latitudes, where it is most likely to occur [7]. In addition, the RH sensor aboard Curiosity is similar to that on the TECP [8], allowing a direct comparison of the near-surface RH measurements at these two different locations on the surface of Mars. REFERENCES: [1] Zent, A. P., et al, 2009, JGR (1991-2012) 114.E3. [2] Tamppari, L. K., et al. 2010, JGR, 115, E00E17. [3] Davy, R., et al., 2010, JGR, 115, E00E13. [4] Whiteway, J., et al., 2009, Science, 325, 68-70. [5] Savijärvi, H., and A. Määttänen, 2010, Q. J. R. Meteorol. Soc., 136, 1497-1505. [6] Fischer, E., et al., 2014, GRL, 41, 4456-4462. [7] Martínez, G., and Rennó, N., 2013, Space Sci. Rev., 175, 29-51. [8] Harri, A-M., et al., 2014, JGR 119

  8. A Sun in the Spectroscopic Binary IM Pegasi, the Guide Star for the Gravity Probe B Mission

    NASA Astrophysics Data System (ADS)

    Marsden, S. C.; Berdyugina, S. V.; Donati, J.-F.; Eaton, J. A.; Williamson, M. H.; Ilyin, I.; Fischer, D. A.; Muñoz, M.; Isaacson, H.; Ratner, M. I.; Semel, M.; Petit, P.; Carter, B. D.

    2005-12-01

    We present the first detection of the secondary of the spectroscopic binary system IM Pegasi (HR 8703), the guide star for the NASA-Stanford relativity gyroscope mission Gravity Probe B. In support of this mission, high-resolution echelle spectra of IM Peg have been obtained on an almost nightly basis. Applying the technique of least-squares deconvolution, we achieve very high signal-to-noise ratio line profiles and detect the orbit of the secondary of the system. Combining almost 700 new radial velocity measurements of both the primary and secondary of the system with previous measurements, we derive improved orbital parameters of the IM Peg system. Using these estimates along with the previously determined range of orbital inclination angles for the system, we find that the primary of IM Peg is a giant of mass 1.8+/-0.2 Msolar, while the secondary is a dwarf of mass 1.0+/-0.1 Msolar.

  9. The Calibration of a Large Number of Scientific Instruments for the Auroral Spatial Structures Probe Sub-Orbital Mission.

    NASA Astrophysics Data System (ADS)

    Swenson, A.; Miller, J.; Neilsen, T. L.; Fish, C. S.; Swenson, C.

    2014-12-01

    The Auroral Spatial Structures Probe (ASSP) is a NASA sounding rocket mission to be launched in the early January 2015 time frame from the Poker Flat Research Range. The primary scientific objective of this mission is to determine the contribution of small spatial and temporal scale fluctuations of the electric fields to the larger-scale processes during active aurora. This will be accomplished through the use of a constellation of six small payloads ejected at high velocity from a sounding rocket. The multiple baseline observations of the electric and magnetic fields will be used to observe variability of both the E-field and the Poynting flux. These observations will be placed in the context of available data, including winds, large scale E-fields, and proxy conductivity (airglow images) observations.Each sub-payload will carry a crossed pair of electric field double-probe sensors, a three-axis magnetometer, and a Langmuir probe. In total there are eight of each instrument type requireing calibration. Since the instruments need to be calibrated over temperature a full calibration of a single instrument is very time-consuming. The decision was made to automate the calibration process. Measurements were taken using a relay switch-box connecting the instruments to test sources. Calibration data were saved into a database. Using post-processing scripts on these databases a calibration for each instrument at each temperature point was made. This approach is a prototype process that might be used for calibrating a large constellation of CubeSats with similar instruments. In this poster we review the ASSP science and mission, and the results of the pre-flight calibration of the science instruments.

  10. Underwater views of STS-5 crewmen Lenoir and Allen during EVA training

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Underwater views of STS-5 crewmen Lenoir and Allen during EVA training. Mission Specialist/Astronaut Joseph P. Allen, wearing an extravehicular mobility unit (EMU) and weighted down to achieve neutral buoyancy, uses a communication system to talk with fellow Mission Specialist/Astronaut William B. Lenoir (out of frame) during underwater simulation of STS-5 extravehicular activity (EVA) (35899); Both mission specialists coordinate their efforts on a chore near the airlock hatch during training. Lenoir is facing the camera. Their background is a full-scale mock-up of the shuttle payload bay (35900); Lenoir works underwater with a portable foot restraint during training underwater. Allen's backpack or mockup for a portable life support system (PLSS) is seen in one corner of the frame (35901).

  11. Hard X-ray imaging from the solar probe. [X ray telescope and mission planning

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.

    1978-01-01

    The solar probe offers a platform with particular advantages for studying solar nonthermal plasma processes via the observations of hard X-radiation from energetic electrons in the chromosphere and corona, these include (1) high sensitivity, (2) a second line of sign (in addition to the earth's) that can aid in three dimensional reconstruction of the source distribution, and, (3) the possibility of correlation with direct measurements of the nonthermal particles from the probe itself.

  12. Substituent effects on dynamics at conical intersections: Allene and methyl allenes

    NASA Astrophysics Data System (ADS)

    Neville, Simon P.; Wang, Yanmei; Boguslavskiy, Andrey E.; Stolow, Albert; Schuurman, Michael S.

    2016-01-01

    We report a joint experimental and theoretical study on the ultrafast excited state dynamics of allene and a series of its methylated analogues (1,2-butadiene, 1,1-dimethylallene, and tetramethylallene) in order to elucidate the conical intersection mediated dynamics that give rise to ultrafast relaxation to the ground electronic state. We use femtosecond time-resolved photoelectron spectroscopy (TRPES) to probe the coupled electronic-vibrational dynamics following UV excitation at 200 nm (6.2 eV). Ab initio multiple spawning (AIMS) simulations are employed to determine the mechanistic details of two competing dynamical pathways to the ground electronic state. In all molecules, these pathways are found to involve as follows: (i) twisting about the central allenic C-C-C axis followed by pyramidalization at one of the terminal carbon atoms and (ii) bending of allene moiety. Importantly, the AIMS trajectory data were used for ab initio simulations of the TRPES, permitting direct comparison with experiment. For each molecule, the decay of the TRPES signal is characterized by short (30 fs, 52 fs, 23 fs) and long (1.8 ps, 3.5 ps, [306 fs, 18 ps]) time constants for 1,2-butadiene, 1,1-dimethylallene, and tetramethylallene, respectively. However, AIMS simulations show that these time constants are only loosely related to the evolution of electronic character and actually more closely correlate to large amplitude motions on the electronic excited state, modulating the instantaneous vertical ionization potentials. Furthermore, the fully substituted tetramethylallene is observed to undergo qualitatively different dynamics, as displacements involving the relatively massive methyl groups impede direct access to the conical intersections which give rise to the ultrafast relaxation dynamics observed in the other species. These results show that the branching between the "twisting" and "bending" pathways can be modified via the selective methylation of the terminal carbon atoms of

  13. A Technology Development Roadmap for a Near-Term Probe-Class X-ray Astrophysics Mission

    NASA Technical Reports Server (NTRS)

    Daelemans, Gerard J.; Petre, Robert; Bookbinder, Jay; Ptak, Andrew; Smith, Randall

    2013-01-01

    This document presents a roadmap, including proposed budget and schedule, for maturing the instrumentation needed for an X-ray astrophysics Probe-class mission. The Physics of the Cosmos (PCOS) Program Office was directed to create this roadmap following the December 2012 NASA Astrophysics Implementation Plan (AIP). Definition of this mission is called for in the AIP, with the possibility of selection in 2015 for a start in 2017. The overall mission capabilities and instrument performance requirements were defined in the 2010 Astronomy and Astrophysics Decadal Survey report, New Worlds, New Horizons in Astronomy and Astrophysics (NWNH), in connection with the highly ranked International X-ray Observatory (IXO). In NWNH, recommendations were provided regarding the size of, and instrumentation needed by, the next large X-ray observatory. Specifically, the key instrumental capability would be an X-ray calorimeter spectrometer at the focus of a large mirror with angular resolution of 10 arc seconds (arcsec) or better. If possible, a grating spectrometer should also be incorporated into the instrument complement. In response to these recommendations, four instrumentation technologies are included in this roadmap. Three of these are critical for an X-ray mission designed to address NWNH questions: segmented X-ray mirrors, transition edge sensor calorimeters, and gratings. Two approaches are described for gratings, which represent the least mature technology and thus most in need of a parallel path for risk reduction. Also, while current CCD detectors would likely meet the mission needs for grating spectrum readout, specific improvements are included as an additional approach for achieving the grating system effective area requirement. The technical steps needed for these technologies to attain technology readiness levels (TRL) of 5 and 6 are described, as well as desirable modest risk reduction steps beyond TRL-6. All of the technology development efforts are currently

  14. Thermal protection system development, testing, and qualification for atmospheric probes and sample return missions. Examples for Saturn, Titan and Stardust-type sample return

    NASA Astrophysics Data System (ADS)

    Venkatapathy, E.; Laub, B.; Hartman, G. J.; Arnold, J. O.; Wright, M. J.; Allen, G. A.

    2009-07-01

    The science community has continued to be interested in planetary entry probes, aerocapture, and sample return missions to improve our understanding of the Solar System. As in the case of the Galileo entry probe, such missions are critical to the understanding not only of the individual planets, but also to further knowledge regarding the formation of the Solar System. It is believed that Saturn probes to depths corresponding to 10 bars will be sufficient to provide the desired data on its atmospheric composition. An aerocapture mission would enable delivery of a satellite to provide insight into how gravitational forces cause dynamic changes in Saturn's ring structure that are akin to the evolution of protoplanetary accretion disks. Heating rates for the "shallow" Saturn probes, Saturn aerocapture, and sample Earth return missions with higher re-entry speeds (13-15 km/s) from Mars, Venus, comets, and asteroids are in the range of 1-6 KW/cm 2. New, mid-density thermal protection system (TPS) materials for such probes can be mission enabling for mass efficiency and also for use on smaller vehicles enabled by advancements in scientific instrumentation. Past consideration of new Jovian multiprobe missions has been considered problematic without the Giant Planet arcjet facility that was used to qualify carbon phenolic for the Galileo probe. This paper describes emerging TPS technologies and the proposed use of an affordable, small 5 MW arcjet that can be used for TPS development, in test gases appropriate for future planetary probe and aerocapture applications. Emerging TPS technologies of interest include new versions of the Apollo Avcoat material and a densified variant of Phenolic Impregnated Carbon Ablator (PICA). Application of these and other TPS materials and the use of other facilities for development and qualification of TPS for Saturn, Titan, and Sample Return missions of the Stardust class with entry speeds from 6.0 to 28.6 km/s are discussed.

  15. Requirements on Atmospheric Entry of Small Probes for Several Planets: Venus, Saturn, Neptune and Uranus in Preparation for the Future ESA Cosmic Vision Missions

    NASA Astrophysics Data System (ADS)

    Tomuta, D.; Rebuffat, D.; Larranaga, J.; Erd, C.; Bavdaz, M.; Falkner, P.

    2011-02-01

    In preparation for the ESA Cosmic Vision new call for medium class missions, a set of entry probes for inner and outer planets have been preliminary investigated by ESA using its Concurrent Design Facility. These Entry Probe missions are hypothetically assumed for launching time 2020-2035. A preliminary design of the probes arrived at a mass of about 300kg. In the following, the study is focused on the entry conditions for each of the planets Venus, Saturn, Neptune and Uranus with the aim to define the conditions for the Entry and Descent System (EDS) and its required technologies. For Venus case, two scenarios where considered: one where the entry probe is released during a typical gravity assist by a large interplanetary mission and another scenario featuring a stand alone mission targeted to Venus. During the entry in Venus atmosphere (mainly composed of CO2 (96.5%) and N2 (3.5%)), the probes are subjected to maximum heat fluxes of 60MW/m2, which is highly demanding in both scenarios. For the outer planet missions, only flyby scenarios with a targeted release of the probe were considered. The entry probes for the outer planets are subjected to heat fluxes above 100MW/m2, which is even more challenging the Thermal Protection Systems (TPS) and therefore requiring the use of special high temperature protection technology to prevent the destruction during the entry. ESA efforts for future missions are directed towards the development of an European Light Ablative Material (ELAM), though used in PEP study only for the Back Cover of the Entry Module. The TPS as well as both radiative and convective heat fluxes need simulations and verification by means of ground facility experiments. Based on the lessons learned from previous mission studies (mission to a near-Earth objects c.f. Marco Polo, Deimos Sample return), an Atmospheric Mars Sample Return is now under study. For sample return missions on return to Earth, a passive re-entry capsule delivering the sample

  16. The Digital Fields Board for the FIELDS instrument suite on the Solar Probe Plus mission: Analog and digital signal processing

    NASA Astrophysics Data System (ADS)

    Malaspina, David M.; Ergun, Robert E.; Bolton, Mary; Kien, Mark; Summers, David; Stevens, Ken; Yehle, Alan; Karlsson, Magnus; Hoxie, Vaughn C.; Bale, Stuart D.; Goetz, Keith

    2016-06-01

    The first in situ measurements of electric and magnetic fields in the near-Sun environment (< 0.25 AU from the Sun) will be made by the FIELDS instrument suite on the Solar Probe Plus mission. The Digital Fields Board (DFB) is an electronics board within FIELDS that performs analog and digital signal processing, as well as digitization, for signals between DC and 60 kHz from five voltage sensors and four search coil magnetometer channels. These nine input signals are processed on the DFB into 26 analog data streams. A specialized application-specific integrated circuit performs analog to digital conversion on all 26 analog channels simultaneously. The DFB then processes the digital data using a field programmable gate array (FPGA), generating a variety of data products, including digitally filtered continuous waveforms, high-rate burst capture waveforms, power spectra, cross spectra, band-pass filter data, and several ancillary products. While the data products are optimized for encounter-based mission operations, they are also highly configurable, a key design aspect for a mission of exploration. This paper describes the analog and digital signal processing used to ensure that the DFB produces high-quality science data, using minimal resources, in the challenging near-Sun environment.

  17. Long Awaited Fundamental Measurement of the Martian Upper Atmosphere from the Langmuir Probe and Waves Instrument on the MAVEN Mission.

    NASA Astrophysics Data System (ADS)

    Andersson, Laila; Andrews, David; Ergun, Bob; Delory, Greg; Morooka, Michiko; Fowler, Chris; McEnulty, Tess; Weber, Tristan; Eriksson, Anders; Malaspina, David; Crary, Frank; Mitchell, David; McFadden, Jim; Halekas, Jasper; Larson, Davin; Connerney, Jack; Espley, Jared; Eparvies, Frank

    2015-04-01

    Electron temperature and density are critical quantities in understanding an upper atmosphere. Approximately 40 years ago, the Viking landers reached the Martian surface, measuring the first (and only) two temperature profiles during it's descent. With the MAVEN mission arriving at Mars details of the Martian ionosphere can agin be studied by a complete plasma package. This paper investigates the first few months of data from the MAVEN mission when the orbit is below 500 km and around the northern hemisphere's terminator. The fo-cus of this presentation is on the different measure-ments that the Langmuir probe and Waves (LPW) in-strument is making on the MAVEN mission. Some of the LPW highlights that will be presented: (a) the long awaited new the electron temperature profiles; (b) the structures observed on the nightside ionosphere; (c) wave-particle insteractions observed below 500 km; and (d) the observed dusty environment at Mars. This presentation is supported by measurements from the other Particle and Fileds (PF) measurements on MAVEN.

  18. Design of the detector to observe the energetic charged particles: a part of the solar X-ray spectrophotometer ChemiX onboard Interhelio-Probe mission

    NASA Astrophysics Data System (ADS)

    Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw; Bakala, Jaroslaw; Siarkowski, Marek; Evgen Kurbatov, mgr..

    2016-07-01

    Cosmic particle radiation may damages payload's electronics, optics, and sensors during of long-term scientific space mission especially the interplanetary ones. That is why it's extremely important to prevent failures of digital electronics, CCDs, semiconductor detectors at the times of passing through regions of enhanced charged particle fluxes. Well developed models of the Earth's radiation belts allow to predict and to protect sensitive equipment against disastrous influence of radiation due to energetic particle contained in the Van Allen belts. In the contrary interplanetary probes flying far away from our planet undergoes passages through clouds of plasma and solar cosmic rays not predictable by present models. Especially these concerns missions planned for non-ecliptic orbits. The practical approach to protect sensitive modules may be to measure the in situ particle fluxes with high time resolution and generation of alarm flags, which will switch off sensitive units of particular scientific equipment. The ChemiX (Chemical composition in X-rays) instrument is being developed by the Solar Physics Division of Polish Space Research Centre for the Interhelio-Probe interplanetary mission. Charged particle bursts can badly affect the regular measurements of X-ray spectra of solar origin. In order to detect presence of these enhanced particle fluxes the Background Particle Monitor (BPM) was developed constituting now a vital part of ChemiX. The BPM measurements of particle fluxes will assist to determine level of X-ray spectra contamination. Simultaneously BPM will measure the energy spectra of ambient particles. We present overall structure, design, technical and a scientific characteristic of BPM, particle sorts, and energy ranges to be registered. We describe nearly autonomous modular structure of BPM consisting of detector head, analogue and digital electronics modules, and of module of secondary power supply [1-3]. Detector head consists of three

  19. Einstein Probe: a proposed small mission for exploring the transient X-ray universe in the multi-messenger era

    NASA Astrophysics Data System (ADS)

    Yuan, Weimin

    2015-08-01

    As a candidate mission in the Space Science Programme of the Chinese Academy of Sciences, the proposed Einstein Probe is a small satellite dedicated to time-domain high-energy astrophysics. Its primary goals are to discover high-energy transients and to monitor variable objects in the soft X-ray band, at higher sensitivity by one order of magnitude than those of the current missions. Its wide-field imaging capability with a field-of-view of 60x60 square degrees is achieved by adopting established technology of micro-pore (MPO) lobster-eye X-ray focusing optics, thereby offering unprecedentedly large Grasp. To allow prompt and detailed follow-up observations of newly-discovered transients, it also carries a narrow-field, more sensitive follow-up X-ray telescope based on the same MPO technology. Public transient alerts will be downlinked rapidly, so as to trigger multi-wavelength follow-up observations from the world-wide community. The scientific objectives of the mission are: to discover otherwise quiescent black holes over all astrophysical mass scales by detecting their rare X-ray transient flares, particularly tidal disruption of stars by massive black holes at galactic centers; to detect and precisely locate the electromagnetic sources of gravitational-wave transients; to carry out systematic surveys of X-ray transients and characterize the variability of X-ray sources, such as high-redshift gamma-ray bursts, supernova shock breakouts, X-ray binaries of compact objects, gamma-ray bursts, active galactic nuclei and stellar coronal flares, etc. By synergy with gravitational-wave and neutrino detectors, the mission is expected to make new discoveries in the upcoming era of multi-messenger astrophysics.

  20. Underwater views of STS-5 crewmen Lenoir and Allen during EVA training

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Underwater views of STS-5 crewmen Lenoir and Allen during EVA training. In this view, Mission Specialist/Astronaut Joseph P. Allen is in the foreground and Mission Specialist/Astronaut William B. Lenoir is at the top of the photography. Both men are wearing extravehicular mobility unit (EMU) space suits and are weighted down to achieve neutral buoyancy in the 25-ft. deep pool. The background is a full-scale mockup of the Space Shuttle's cargo bay area. Divers assist in the training (35894); Allen goes through a simulation exercise with divers all around (35985); Divers assist the fully suited and tethered Lenoir as he simulates work to be done in the shuttle cargo bay (35986); Lenoir anchors himself to a full-scale mockup of the shuttle orbiter's cargo bay and holds onto a restraining device (35987).

  1. Design reference missions for the exoplanet starshade (Exo-S) probe-class study

    NASA Astrophysics Data System (ADS)

    Trabert, Rachel; Shaklan, Stuart; Lisman, P. Douglas; Roberge, Aki; Turnbull, Margaret; Domagal-Goldman, Shawn; Stark, Christopher

    2015-09-01

    Exo-S is a direct imaging space-based mission to discover and characterize exoplanets. The mission is comprised of two formation-flying spacecraft - a starlight suppressing starshade and a telescope separated by ~30,000 km. To align the starshade between the target star and telescope, one of the two spacecraft must perform a retargeting slew. This drives the need for a sophisticated program to help optimize this path to maximize target yield within mission constraints such as solar and earth avoidance angles, thrust and fuel limitations, and target scheduling for previously-discovered known giant planets. The Design Reference Mission (DRM) describes the sequence of observations to be performed and estimates the number of planets that will be detected and characterized. It is executed with a Matlab-based tool developed for the Exo-S Study. Here we analyze four case studies: • Case 1: Starshade with a 1.1m dedicated telescope prioritizing the search for earths in the Habitable Zone (HZ). • Case 2: Starshade with a 1.1m dedicated telescope focused on maximizing planet harvest return and characterization. • Case 3: Starshade that rendezvous with a 2.4 m shared telescope prioritizing the search for earths in the HZ. • Case 4: A Rendezvous Earth Finder mission based on a 40-m diameter starshade with a 2.4 m telescope, operating for 4 years, and focused exclusively on detecting Earths in the HZ Previous starshade DRM tools have been reported in the literature, all of them focused on detection and/or characterization of Earth-twins in the habitable zone. This study has taken then next step and focused on total planet harvest including known Gas Giants, Earths in the Habitable Zone and elsewhere, super-earths, sub-Neptunes, and Jupiters. The DRM employs a hierarchical approach: an observation schedule of known radial velocity gas giants, whose availabilities for observation are known form their orbital parameters, forms a "framework" of observation that have a high

  2. H. Julian Allen: An Appreciation

    NASA Astrophysics Data System (ADS)

    Vincenti, Walter G.; Boyd, John W.; Bugos, Glenn E.

    2007-01-01

    Harvey Allen is best known as the genius behind the blunt-body concept, published in 1953, which enables spacecraft to return safely home through Earth's dense atmosphere. He was also an extraordinary research leader, who led a world-class research program in hypersonics at the NACA Ames Aeronautical Laboratory. This paper reviews his career as one of America's leading theorists and experimenters, including his engineering education at Stanford, his work on the inverse problem of calculating the airfoil profile to obtain a desired pressure distribution, his hand in constructing wind tunnels and experimental facilities at Ames, and his pioneering and wide-ranging work on atmospheric re-entry. It concludes with an appreciation of his uniquely inspirational style of research management, and of his magnetic personality.

  3. Pneumatic and Percussive Penetration Approaches for Heat Flow Probe Emplacement on Robotic Lunar Missions

    NASA Astrophysics Data System (ADS)

    Zacny, K.; Nagihara, S.; Hedlund, M.; Paulsen, G.; Shasho, J.; Mumm, E.; Kumar, N.; Szwarc, T.; Chu, P.; Craft, J.; Taylor, P.; Milam, M.

    2013-11-01

    In this paper, the development of heat flow probes for measuring the geothermal gradient and conductivity of lunar regolith are presented. These two measurements are the required information for determining the heat flow of a planetary body. Considering the Moon as an example, heat flow properties are very important information for studying the radiogenic isotopes, the thermal evolution and differentiation history, and the mechanical properties of the interior. In order to obtain the best measurements, the sensors must be extended to a depth of at least 3 m, i.e. beyond the depth of significant thermal cycles. Two approaches to heat flow deployment and measurement are discussed in this paper: a percussive approach and a pneumatic approach. The percussive approach utilizes a high frequency hammer to drive a cone penetrometer into the lunar simulant. Ring-like thermal sensors (heaters and temperature sensors) on the penetrometer rod are deployed into the simulant every 30 cm as the penetrometer penetrates to the required 3 m depth. Once the target depth has been achieved, the deployment rod is removed from the simulant, eliminating any thermal path to the lander. The pneumatic approach relies on pressurized gas to excavate, using a cone-shaped nozzle to penetrate the simulant. The nozzle is attached to a coiled stem with thermal sensors embedded along the length of the stem. As the simulant is being lofted out of the hole by the escaping gas, the stem is progressively reeled out from a spool, thus moving the cone deeper into the hole. Thermal conductivity is measured using a needle probe attached to the end of the cone. Breadboard prototypes of these two heat flow probe systems have been constructed and successfully tested under lunar-like conditions to approximately 70 cm, which was the maximum possible depth allowed by the size of the test bin and the chamber.

  4. Status of the cryogenic inertial reference system for the Gravity Probe B mission

    NASA Technical Reports Server (NTRS)

    Lipa, J. A.; Gwo, D.-H.; Kirschman, R. K.

    1993-01-01

    We describe the status of the development and testing program for the inertial reference system for the Gravity Probe B gyroscopes. The gyroscope housings are attached to a cryogenic telescope with a 14 cm aperture that continuously points at a guide star. The star image is split to provide quadrant pointing information which is used to steer the spacecraft. This data is also combined with the gyro readout data to provide an absolute precession measurement. Motion of the guide star is independently checked by reference to background galaxies. Room temperature testing of a prototype telescope has been completed and preparations are being made for low temperature tests.

  5. CASSIOPE Enhanced Polar Outflow Probe (e-POP) Small Satellite Mission: Space Plasma Observations and International Collaborations

    NASA Astrophysics Data System (ADS)

    Yau, A. W.; James, H. G.

    2009-06-01

    In-situ observation of the micro-scale characteristics of plasma acceleration and related outflow processes is a primary scientific target of the Canadian Enhanced Polar Outflow Probe (e-POP) small satellite mission. The e-POP instrument payload will include imaging plasma and neutral particle sensors, magnetometers, dual-frequency GPS receivers, CCD cameras, a radio wave receiver and a beacon transmitter. The imaging plasma sensors will measure particle distributions and the magnetometers will measure field-aligned currents on the time scale of 10 ms and spatial scale of ~100 m. The CCD cameras will perform auroral imaging on the time scale of 100 ms and at spatial (pixel) resolution up to 0.4 km. The GPS and radio-wave receivers will perform near real-time imaging studies of the ionosphere in conjunction with ground-based radars, and the beacon transmitter in conjunction with ground receiving stations. The e-POP payload will be flown on the Canadian CASSIOPE small satellite, which is scheduled for launch in late 2008 into a polar orbit (325×1500 km, 80° inclination). International collaboration is an important and integral part of the e-POP mission strategy. Two of the 8 e-POP science instruments will be contributed by JAXA/ISAS, Japan, and Naval Research Laboratory, USA, respectively. Many of the planned e-POP investigations will entail coordinated observations using Canadian as well as foreign ground facilities, including magnetic and optical observatories, radars and heaters, such as the HAARP facility in Alaska, the EISCAT radar, and the NSF Antarctic facility. International collaboration in these investigations is expected to significantly enhance the science returns of the e-POP mission.

  6. A Study of the Structure of the Source Region of the Solar Wind in Support of a Solar Probe Mission

    NASA Technical Reports Server (NTRS)

    Habbal, Shadia R.; Forman, M. A. (Technical Monitor)

    2001-01-01

    Despite the richness of the information about the physical properties and the structure of the solar wind provided by the Ulysses and SOHO (Solar and Heliospheric Observatory) observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow solar wind, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the solar atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the solar wind, is the corona between 1 and 30 R(sub s). A Solar Probe mission offers an unprecedented opportunity to explore this frontier. Its uniqueness stems from its trajectory in a plane perpendicular to the ecliptic which reaches within 9 R(sub s) of the solar surface over the poles and 3 - 9 R(sub s) at the equator. With a complement of simultaneous in situ and remote sensing observations, this mission is destined to detect remnants and signatures of the processes which heat the corona and accelerate the solar wind. In support of this mission, we fulfilled the following two long-term projects: (1) Study of the evolution of waves and turbulence in the solar wind (2) Exploration of signatures of physical processes and structures in the corona. A summary of the tasks achieved in support of these projects are given below. In addition, funds were provided to support the Solar Wind 9 International Conference which was held in October 1998. A brief report on the conference is also described in what follows.

  7. Erosion of carbon/carbon by solar wind charged particle radiation during a solar probe mission

    NASA Technical Reports Server (NTRS)

    Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry

    1991-01-01

    The possible erosion of a carbon/carbon thermal shield by solar wind-charged particle radiation is reviewed. The present knowledge of erosion data for carbon and/or graphite is surveyed, and an explanation of erosion mechanisms under different charged particle environments is discussed. The highest erosion is expected at four solar radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case solar wind storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by solar wind could be greater than by nominal free sublimation during solar wind storm conditions at four solar radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four solar radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.

  8. Camera, Hand Lens, and Microscope Probe (CHAMP): An Instrument Proposed for the 2009 MSL Rover Mission

    NASA Technical Reports Server (NTRS)

    Mungas, Greg S.; Beegle, Luther W.; Boynton, John E.; Lee, Pascal; Shidemantle, Ritch; Fisher, Ted

    2004-01-01

    The Camera, Hand Lens, and Microscope Probe (CHAMP) will allow examination of martian surface features and materials (terrain, rocks, soils, samples) on spatial scales ranging from kilometers to micrometers, thus enabling both microscopy and context imaging with high operational flexibility. CHAMP is designed to allow the detailed and quantitative investigation of a wide range of geologic features and processes on Mars, leading to a better quantitative understanding of the evolution of the martian surface environment through time. In particular, CHAMP will provide key data that will help understand the local region explored by Mars Surface Laboratory (MSL) as a potential habitat for life. CHAMP will also support other anticipated MSL investigations, in particular by helping identify and select the highest priority targets for sample collection and analysis by the MSL's analytical suite.

  9. Modular Functionalization of Allenes to Aminated Stereotriads

    PubMed Central

    Adams, Christopher S.; Boralsky, Luke A.; Guzei, Ilia A.; Schomaker, Jennifer M.

    2014-01-01

    Nitrogen-containing stereotriads- compounds with three adjacent stereodefined carbons- are commonly found in biologically important molecules. However, the preparation of molecules bearing these motifs can be challenging. Herein, we describe a modular oxidation protocol which converts a substituted allene to a triply functionalized amine of the form C-X/C-N/CY. The key step employs a Rh-catalyzed intramolecular conversion of the allene to a strained bicyclic methylene aziridine. This reactive intermediate is further elaborated to the target products, often in one reaction vessel and with effective transfer of the axial chirality of the allene to point chirality in the stereotriad. PMID:22708990

  10. [2+2+1] cyclization of allenes.

    PubMed

    Kitagaki, S; Inagaki, F; Mukai, C

    2014-05-01

    The [2+2+1] cyclization of an alkyne, an alkene and carbon monoxide, i.e., the Pauson-Khand reaction, is one of the most powerful tools for constructing a five-membered ring. In place of the alkene or alkyne part, the use of an allene functionality has proven to make this reaction more valuable for organic synthesis. This review focuses on the origin and progress of the allenic [2+2+1] cyclocarbonylation, including the chirality transfer of the allene and its synthetic applications. PMID:24514744

  11. The Axial Double Probe and Fields Signal Processing for the MMS Mission

    NASA Astrophysics Data System (ADS)

    Ergun, R. E.; Tucker, S.; Westfall, J.; Goodrich, K. A.; Malaspina, D. M.; Summers, D.; Wallace, J.; Karlsson, M.; Mack, J.; Brennan, N.; Pyke, B.; Withnell, P.; Torbert, R.; Macri, J.; Rau, D.; Dors, I.; Needell, J.; Lindqvist, P.-A.; Olsson, G.; Cully, C. M.

    2016-03-01

    The Axial Double Probe (ADP) instrument measures the DC to ˜100 kHz electric field along the spin axis of the Magnetospheric Multiscale (MMS) spacecraft (Burch et al., Space Sci. Rev., 2014, this issue), completing the vector electric field when combined with the spin plane double probes (SDP) (Torbert et al., Space Sci. Rev., 2014, this issue, Lindqvist et al., Space Sci. Rev., 2014, this issue). Two cylindrical sensors are separated by over 30 m tip-to-tip, the longest baseline on an axial DC electric field ever attempted in space. The ADP on each of the spacecraft consists of two identical, 12.67 m graphite coilable booms with second, smaller 2.25 m booms mounted on their ends. A significant effort was carried out to assure that the potential field of the MMS spacecraft acts equally on the two sensors and that photo- and secondary electron currents do not vary over the spacecraft spin. The ADP on MMS is expected to measure DC electric field with a precision of ˜1 mV/m, a resolution of ˜25 μV/m, and a range of ˜±1 V/m in most of the plasma environments MMS will encounter. The Digital Signal Processing (DSP) units on the MMS spacecraft are designed to perform analog conditioning, analog-to-digital (A/D) conversion, and digital processing on the ADP, SDP, and search coil magnetometer (SCM) (Le Contel et al., Space Sci. Rev., 2014, this issue) signals. The DSP units include digital filters, spectral processing, a high-speed burst memory, a solitary structure detector, and data compression. The DSP uses precision analog processing with, in most cases, >100 dB in dynamic range, better that -80 dB common mode rejection in electric field ( E) signal processing, and better that -80 dB cross talk between the E and SCM ( B) signals. The A/D conversion is at 16 bits with ˜1/4 LSB accuracy and ˜1 LSB noise. The digital signal processing is powerful and highly flexible allowing for maximum scientific return under a limited telemetry volume. The ADP and DSP are

  12. Obituary: James Alfred Van Allen, 1914-2006

    NASA Astrophysics Data System (ADS)

    Ludwig, George H.; McIlwain, Carl Edwin

    2006-12-01

    James Alfred Van Allen, world-renowned space scientist, died 9 August 2006 at the age of ninety-one. He succumbed to heart failure after a ten-week period of declining health. Van Allen served for his entire sixty-seven-year professional career as an amazingly productive researcher, space science spokesman, inspired teacher, and valued colleague. The realization by him and his associates that charged particles are trapped by the Earth's magnetic field began a whole new field of research, magnetospheric physics. Following that initial discovery, he and his associates quickly extended their observations, first to the inner planets, and then to the rest of the planets and beyond. During his tenure at Iowa, he and his group flew instruments on more than sixty successful Earth satellites and planetary spacecraft, including the first missions to the planets Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Van Allen's lifetime publication list numbers more than 275, of which many are widely-cited, seminal papers. He was the sole author of more than 125 of those papers. Beyond the research laboratory, Van Allen worked energetically throughout his career in establishing space research as a new branch of human inquiry. He was among the most sought-after as a committee member and adviser, working at the highest levels of government, including the White House and Congress, and at all levels of the national and international research establishments. Many presentations in the non-scientific arena helped to bring the exciting discoveries and challenges of space research to the attention of the general public. James Van Allen (Van to his many friends and colleagues) was born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, the second of four sons of Alfred Morris Van Allen and Alma Olney Van Allen. After high school in Mount Pleasant, he entered Iowa Wesleyan College, majoring in physics and graduating summa cum laude. While there, he was introduced to geophysics

  13. Debris Disk Science Enabled by a Probe-scale Space Coronagraph Mission

    NASA Astrophysics Data System (ADS)

    Stapelfeldt, Karl R.; Trauger, J. T.; Krist, J. E.

    2010-01-01

    Debris disks are the signposts of planetary systems: collisions between rocky/icy parent bodies maintain debris dust around main sequence stars against losses to radiation pressure and P-R drag. Debris disk structures show the location of asteroid/Kuiper belts around nearby stars, and reflect dynamical interactions with local extrasolar planets. Only 17 debris disks with high optical depth have been spatially resolved to date in scattered light images made with the Hubble Space Telescope and ground-based adaptive optics. Hundreds more with lower optical depth have been identified among nearby stars through far-IR photometry with the Spitzer Space Telescope, and more should follow in the next few years from Herschel. The most capable means for imaging this larger disk population is a next-generation coronagraphic instrument on a 1.5m class optical space telescope. Utilizing high-contrasat imaging simulations validated by laboratory demonstrations on the JPL High Contrast Imaging Testbed, we show that such a mission will be capable of imaging Kuiper disk structures down to the 10 zodi level, and exozodiacal dust down to the 1 zodi level, around a major sample of nearby stars. This performance goes well beyond what is about to be achieved with upcoming extreme adaptive optics systems or the ALMA array, and thus provides the best path for imaging exploration of planetary systems in the solar neighborhood.

  14. Utilizing Mars Global Reference Atmospheric Model (Mars-GRAM 2005) to Evaluate Entry Probe Mission Sites

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.

    2008-01-01

    Engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL)1. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: a) TES Mapping Years 1 and 2, with Mars-GRAM data coming from MGCM model results driven by observed TES dust optical depth; and b) TES Mapping Year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from MGCM model results driven by selected values of globally-uniform dust optical depth. From the surface to 80 km altitude, Mars-GRAM is based on NASA Ames Mars General Circulation Model (MGCM). Mars-GRAM and MGCM use surface topography from Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA), with altitudes referenced to the MOLA areoid, or constant potential surface. Mars-GRAM 2005 has been validated2 against Radio Science data, and both nadir and limb data from the Thermal Emission Spectrometer (TES)

  15. Van Allen Discovery Most Important

    NASA Technical Reports Server (NTRS)

    Jastrow, R.

    1959-01-01

    The first step toward the exploration of space occurred approximately 22 months ago as a part of the International Geophysical Year. In the short interval since October, 1957, the new tools of research, the satellite and the space rocket, have produced two unexpected results of fundamental scientific importance. First, instruments placed in the Explorer satellites by James A. Van Allen have revealed the existence of layers of energetic particles in the outer atmosphere. This discovery constitutes the most significant research achievement of the IGY satellite program. The layers may provide the explanation for the aurora and other geophysical phenomena, and they will also influence the design of vehicles for manned space flight, whose occupants must be shielded against their harmful biological effects. Second, the shape of the earth has been determined very accurately with the aid of data from the first Vanguard. As a result of this investigation, we have found that our planet tends toward the shape of a pear, with its stem at the North Pole. This discovery may produce major changes in our ideas on the interior structure of the earth.

  16. The Integrated Science Investigation of the Sun (ISIS): Energetic Particle Measurements for the Solar Probe Plus Mission

    NASA Technical Reports Server (NTRS)

    McComas, D. J.; Christian, E. R.; Wiedenbeck, M. E.; McNutt, R. L.; Cummings, A. C.; Desai, M. I.; Giacalone, J.; Hill, M. E.; Mewaldt, R. A.; Krimigis, SA. M.; Livi, S. A.; Mitchell, D. G.; Matthaeus, W. H.; Roelof, E. C.; Stone, E. C.; Schwardron, N. A.; vonRosenvinge, T. T.

    2011-01-01

    One of the major goals of NASA's Solar Probe Plus (SPP) mission is to determine the mechanisms that accelerate and transport high-energy particles from the solar atmosphere out into the heliosphere. Processes such as coronal mass ejections and solar flares, which peak roughly every 11 years around solar maximum, release huge quantities of energized matter, magnetic fields and electromagnetic radiation into space. The high-energy particles, known as solar energetic particles or SEPs, present a serious radiation threat to human explorers living and working outside low-Earth orbit and to technological assets such as communications and scientific satellites in space. This talk describes the Integrated Science Investigation of the Sun (ISIS) - Energetic Particle Instrument suite. ISIS measures key properties such as intensities, energy spectra, composition, and angular distributions of the low-energy suprathermal source populations, as well as the more hazardous, higher energy particles ejected from the Sun. By making the first-ever direct measurements of the near-Sun regions where the acceleration takes place, ISIS will provide the critical measurements that, when integrated with other SPP instruments and with solar and interplanetary observations, will lead to a revolutionary new understanding of the Sun and major drivers of solar system space weather.

  17. The Integrated Science Investigation of the Sun (ISIS): Energetic Particle Measurements for the Solar Probe Plus Mission

    NASA Astrophysics Data System (ADS)

    Scherrer, J.; McComas, D. J.; Christian, E. R.; Cummings, A. C.; Desai, M. I.; Giacalone, J.; Hill, M. E.; Krimigis, S. M.; Livi, S. A.; McNutt, R. L.; Mewaldt, R. A.; Mitchell, D. G.; Matthaeus, W. H.; Roelof, E. C.; von Rosenvinge, T. T.; Schwadron, N. A.; Stone, E. C.; Velli, M. M.; Wiedenbeck, M. E.

    2010-12-01

    One of the major goals of NASA’s Solar Probe Plus (SPP) mission is to determine the mechanisms that accelerate and transport high-energy particles from the solar atmosphere out into the heliosphere. During the height of solar activity, which occurs roughly once every 11 years, processes such as coronal mass ejections and solar flares release huge quantities of energized matter, magnetic fields and electromagnetic radiation into space. These high-energy particles, known as solar energetic particles or SEPs, present a serious radiation threat to human explorers living and working outside low-Earth orbit and to technological assets such as communications and scientific satellites in space. This talk describes the Integrated Science Investigation of the Sun (ISIS) - Energetic Particle Instrument suite. ISIS measures key properties such as intensities, energy spectra, composition, and angular distributions of the low-energy suprathermal source populations, as well as the more hazardous, higher energy particles ejected from the Sun. By making the first-ever direct measurements of the near-Sun regions where the acceleration takes place, ISIS will provide the critical measurements that, when integrated with other SPP instruments and with solar and interplanetary observations, will lead to a much deeper understanding of the Sun and major drivers of solar system space weather.

  18. Density Structures Within the Martian Ionosphere from the Langmuir Probe and Waves Instrument on the MAVEN Mission

    NASA Astrophysics Data System (ADS)

    McEnulty, Tess; Andrews, David; Andersson, Laila; Ergun, Robert E.; Delory, Greg T.; Fowler, Chris M.; Morooka, MIchiko W.; Weber, Tristan; Eriksson, Anders I.; Mitchell, David L.; McFadden, James P.; Halekas, Jasper; Larson, Davin; Connerney, Jack; Espley, Jared; Eparvier, Francis G.

    2015-04-01

    MAVEN is the first mission to Mars that has included a full suite of particles and fields instruments, allowing characterization of the plasma environment from the solar wind down to ~125-150 km altitude. These altitudes are below the exobase, and well into the ionosphere. The ionospheric density had not been measured locally down to these altitudes before MAVEN, and previous spacecraft that did measure the density at higher altitudes did not include full particles and fields suites. The Langmuir Probe and Waves (LPW) instrument on MAVEN provides measurements of the plasma frequency that allow the density to be determined within 5%. Since the plasma line is not always present, the LPW instrument was designed to be able to broadcast white noise to stimulate the plasma. This broadcasting feature has proven very successful and for some orbits the plasma line is observed nearly continuously. The cadence of these measurements within the ionosphere allows the density to be determined with a spatial resolution as small as ~8 to ~16 km. In this paper, observations of electron density structures from the first 6 months of operation are presented. During this time period the orbit precessed, so measurements were made both on the dayside and nightside. Observed density structures include variations of almost 2 orders of magnitude within ~40 km along the orbital track below 300 km. Observations of these density structures are presented with supporting measurements from the other particles and fields instruments.

  19. Cassini Mission

    SciTech Connect

    Mitchell, Robert

    2005-08-10

    The Cassini/Huygens mission is a joint NASA/European Space Agency/Italian Space Agency project which has a spacecraft currently in orbit about Saturn, and has successfully sent an atmospheric probe through the atmosphere of Saturn's largest moon Titan and down to its previously hidden surface. This presentation will describe the overall mission, how it got a rather massive spacecraft to Saturn, and will cover some of the scientific results of the mission to date.

  20. Stable indications of relic gravitational waves in Wilkinson Microwave Anisotropy Probe data and forecasts for the Planck mission

    SciTech Connect

    Zhao, W.; Baskaran, D.; Grishchuk, L. P.

    2009-10-15

    The relic gravitational waves are the cleanest probe of the violent times in the very early history of the Universe. They are expected to leave signatures in the observed cosmic microwave background anisotropies. We significantly improved our previous analysis [W. Zhao, D. Baskaran, and L. P. Grishchuk, Phys. Rev. D 79, 023002 (2009)] of the 5-year WMAP TT and TE data at lower multipoles l. This more general analysis returned essentially the same maximum likelihood result (unfortunately, surrounded by large remaining uncertainties): The relic gravitational waves are present and they are responsible for approximately 20% of the temperature quadrupole. We identify and discuss the reasons by which the contribution of gravitational waves can be overlooked in a data analysis. One of the reasons is a misleading reliance on data from very high multipoles l and another a too narrow understanding of the problem as the search for B modes of polarization, rather than the detection of relic gravitational waves with the help of all correlation functions. Our analysis of WMAP5 data has led to the identification of a whole family of models characterized by relatively high values of the likelihood function. Using the Fisher matrix formalism we formulated forecasts for Planck mission in the context of this family of models. We explore in detail various 'optimistic', 'pessimistic', and 'dream case' scenarios. We show that in some circumstances the B-mode detection may be very inconclusive, at the level of signal-to-noise ratio S/N=1.75, whereas a smarter data analysis can reveal the same gravitational wave signal at S/N=6.48. The final result is encouraging. Even under unfavorable conditions in terms of instrumental noises and foregrounds, the relic gravitational waves, if they are characterized by the maximum likelihood parameters that we found from WMAP5 data, will be detected by Planck at the level S/N=3.65.

  1. Astronaut Allen during extravehicular activity (EVA) training in CCT

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In the JSC Space Vehicle Mockup Facility, astronaut Andrew M. Allen retrieves gear to rehearse a suit-donning exercise on the middeck. Allen's very realistic environs are provided by the shuttle crew compartment trainer (CCT).

  2. A Century after Van Allen's Birth: Conclusion of Reconnaissance of Radiation Belts in the Solar System

    NASA Astrophysics Data System (ADS)

    Krimigis, S. M.

    2014-12-01

    On May 1, 1958 in the Great Hall of the US National Academy of Sciences, James A. Van Allen, having instrumented Explorer-1 and follow-on satellites with radiation detectors, announced the discovery of intense radiation at high altitudes above Earth. The press dubbed the doughnut-shaped structures "Van Allen Belts" (VAB). Soon thereafter, the search began for VAB at nearby planets. Mariner 2 flew by Venus in 1962 at a distance of 41,000 km, but no radiation was detected. The Mariner 4 mission to Mars did not observe planet-associated increase in radiation, but scaling arguments with Earth's magnetosphere yielded an upper limit to the ratio of magnetic moments of MM/ME < 0.001 (Van Allen et al, 1965). Similarly, the Mariner 5 flyby closer to Venus resulted in a ratio of magnetic moments < 0.001 (Van Allen et al, 1967), dealing a blow to the expectation that all planetary bodies must possess significant VAB. The flyby of Mercury in 1974 by Mariner 10 revealed a weak magnetic field, but the presence of durably trapped higher energy particles remained controversial until MESSENGER in 2011.The first flybys of Jupiter by Pioneers 10, 11 in 1973 and 1974, respectively, measured a plethora of energetic particles in Jupiter's magnetosphere and established the fact that their intensities were rotationally modulated. Later flybys of Jupiter and Saturn by the two Voyagers in 1979 and 1981 revealed that those magnetospheres possessed their own internal plasma source(s) and radiation belts. Subsequent discoveries of Van Allen belts at Uranus and Neptune by Voyager 2 demonstrated that VAB are the rule rather than the exception in planetary environments. We now know from the Voyagers and through Energetic Neutral Atom images from Cassini and IBEX that an immense energetic particle population surrounds the heliosphere itself. Thus, the reconnaissance of radiation belts of our solar system has been completed, some 56 years after the discovery of the Van Allen Belts at Earth.

  3. Rejuvenating Allen's Arc with the Geometric Mean.

    ERIC Educational Resources Information Center

    Phillips, William A.

    1994-01-01

    Contends that, despite ongoing criticism, Allen's arc elasticity formula remains entrenched in the microeconomics principles curriculum. Reviews the evolution and continuing scrutiny of the formula. Argues that the use of the geometric mean offers pedagogical advantages over the traditional arithmetic mean approach. (CFR)

  4. Stable indications of relic gravitational waves in Wilkinson Microwave Anisotropy Probe data and forecasts for the Planck mission

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Baskaran, D.; Grishchuk, L. P.

    2009-10-01

    The relic gravitational waves are the cleanest probe of the violent times in the very early history of the Universe. They are expected to leave signatures in the observed cosmic microwave background anisotropies. We significantly improved our previous analysis [W. Zhao, D. Baskaran, and L. P. Grishchuk, Phys. Rev. DPRVDAQ1550-7998 79, 023002 (2009)10.1103/PhysRevD.79.023002] of the 5-year WMAP TT and TE data at lower multipoles ℓ. This more general analysis returned essentially the same maximum likelihood result (unfortunately, surrounded by large remaining uncertainties): The relic gravitational waves are present and they are responsible for approximately 20% of the temperature quadrupole. We identify and discuss the reasons by which the contribution of gravitational waves can be overlooked in a data analysis. One of the reasons is a misleading reliance on data from very high multipoles ℓ and another a too narrow understanding of the problem as the search for B modes of polarization, rather than the detection of relic gravitational waves with the help of all correlation functions. Our analysis of WMAP5 data has led to the identification of a whole family of models characterized by relatively high values of the likelihood function. Using the Fisher matrix formalism we formulated forecasts for Planck mission in the context of this family of models. We explore in detail various “optimistic,” “pessimistic,” and “dream case” scenarios. We show that in some circumstances the B-mode detection may be very inconclusive, at the level of signal-to-noise ratio S/N=1.75, whereas a smarter data analysis can reveal the same gravitational wave signal at S/N=6.48. The final result is encouraging. Even under unfavorable conditions in terms of instrumental noises and foregrounds, the relic gravitational waves, if they are characterized by the maximum likelihood parameters that we found from WMAP5 data, will be detected by Planck at the level S/N=3.65.

  5. H. Julian Allen with Blunt Body Theory

    NASA Technical Reports Server (NTRS)

    1957-01-01

    H. Julian Allen is best known for his 'Blunt Body Theory' of aerodynamics, a design technique for alleviating the severe re-entry heating problem which was then delaying the development of ballistic missiles. His findings revolutionized the fundamental design of ballistic missle re-entry shapes. Subsequently, applied research led to applications of the 'blunt' shape to ballistic missles and spacecraft which were intended to re-enter the Earth's atmosphere. This application led to the design of ablative heat shields that protected the Mercury, Gemini and Apollo astronauts as their space capsules re- entered the Earth's atmosphere. 'Harvey' Allen as he was called by most, was not only a brilliant scientist and aeronautical engineer but was also admired for his kindness, thoughtfulness and sense of humor. Among his many other accomplishments, Harvey Allen served as Center Director of the NASA Ames Research Center from 1965 to 1969. He died of a heart attack on January 29, 1977 at the age of 66.

  6. Interplanetary mission planning

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A long range plan for solar system exploration is presented. The subjects discussed are: (1) science payload for first Jupiter orbiters, (2) Mercury orbiter mission study, (3) preliminary analysis of Uranus/Neptune entry probes for Grand Tour Missions, (4) comet rendezvous mission study, (5) a survey of interstellar missions, (6) a survey of candidate missions to explore rings of Saturn, and (7) preliminary analysis of Venus orbit radar missions.

  7. Probing the post-newtonian physics of semi-conservative metric theories through secular tidal effects in satellite gradiometry missions

    NASA Astrophysics Data System (ADS)

    Qiang, Li-E.; Xu, Peng

    2016-04-01

    The existence of relativistic secular tidal effects along orbit motions will largely improve the measurement accuracies of relativistic gravitational gradients with orbiting gradiometers. With the continuous advances in technologies related to gradiometry and the improvements in their resolutions, it is feasible for future satellite gradiometry missions to carry out precision relativistic experiments and impose constraints on modern theories of gravity. In this work, we study the theoretical principles of measuring directly the secular post-Newtonian (PN) tidal effects in semi-conservative metric theories with satellite gradiometry missions. The isolations of the related PN parameters in the readouts of an orbiting three-axis gradiometer is discussed.

  8. Maximal tractable subclasses of Allen`s interval algebra: Preliminary report

    SciTech Connect

    Drakengren, T.; Jonsson, P.

    1996-12-31

    This paper continues Nebel and Burckert`s investigation of Allen`s interval algebra by presenting nine more maximal tractable subclasses of the algebra (provided that P {ne} NP), in addition to their previously reported ORD-Horn subclass. Furthermore, twelve tractable subclasses are identified, whose maximality is riot decided. Four of these can express the notion of sequentiality between intervals, which is not possible in the ORD-Horn algebra. The satisfiability algorithm, which is common for all the algebras, is shown to be linear.

  9. The Lavoisier mission : A system of descent probe and balloon flotilla for geochemical investigation of the deep atmosphere and surface of Venus

    NASA Astrophysics Data System (ADS)

    Chassefière, E.; Berthelier, J. J.; Bertaux, J.-L.; Quèmerais, E.; Pommereau, J.-P.; Rannou, P.; Raulin, F.; Coll, P.; Coscia, D.; Jambon, A.; Sarda, P.; Sabroux, J. C.; Vitter, G.; Le Pichon, A.; Landeau, B.; Lognonné, P.; Cohen, Y.; Vergniole, S.; Hulot, G.; Mandéa, M.; Pineau, J.-F.; Bézard, B.; Keller, H. U.; Titov, D.; Breuer, D.; Szego, K.; Ferencz, Cs.; Roos-Serote, M.; Korablev, O.; Linkin, V.; Rodrigo, R.; Taylor, F. W.; Harri, A.-M.

    Lavoisier mission is a joint effort of eight European countries and a technological challenge aimed at investigating the lower atmosphere and the surface of Venus. The mission consists of a descent probe and three balloons to be deployed below the cloud deck. Its main scientific objectives may be summarized as following : (i) composition of the deep atmosphere : noble gas (elemental/isotopic), molecular species (elemental/ isotopic), oxygen fugacity; vertical/horizontal/temporal variability; (ii) infrared spectroscopy and radiometry (molecular composition, radiative transfer); (iii) dynamics of the atmosphere : p, T, acceleration measurements, balloon localization through VLBI, meteorological events signed by acoustic waves, atmospheric mixing as imprinted on radioactive tracers; (iv) surface morphology and mineralogy through near infrared imaging on dayside, surface temperature through NIR imaging on nightside. Additional tentative objectives are search for (a) atmospheric electrical activity (optically, radioelectrically, acoustically), (b) crustal outgassing and/or volcanic activity : acoustic activity, horizontal/vertical distribution of radioactive tracers, (c) seismic activity : acoustic waves transmitted from crust to atmosphere, and (d) remanent and/or intrinsic magnetic field. Lavoisier was proposed to ESA in response to the F2/F3 mission Announcement of Opportunity at the beginning of 2000, but it was not selected for the assessment study. A wide international partnership was created for this occasion, including Finland (FMI), France (IPSL, MAGIE, Université Orsay, IPSN, INPG, CEA, IPGP, Obs. Paris-Meudon), Germany (MPAe, Univ. Muenster), Hungary (KFKI, Univ. Eotvos), Portugal (OAL), Russia (IKI), Spain (IAA), United Kingdom (Univ. Oxford).

  10. 4. Historic American Buildings Survey Harold Allen, Photographer 19 June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Historic American Buildings Survey Harold Allen, Photographer 19 June 1965 SANCTUARY FROM ENTRANCE - Holy Trinity Russian & Greek Orthodox Church, 1121 North Leavitt Street, Chicago, Cook County, IL

  11. 5. Historic American Buildings Survey Harold Allen, Photographer 19 June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey Harold Allen, Photographer 19 June 1965 ICONOSTASIS AND CHANDELIER - Holy Trinity Russian & Greek Orthodox Church, 1121 North Leavitt Street, Chicago, Cook County, IL

  12. Minerva Allen, "A Few Good Words": Interview with Minerva Allen, October 25, 1985.

    ERIC Educational Resources Information Center

    Scholer, Bo

    1987-01-01

    Minerva Allen, Assinibone tribal historian and mediator in dealings with off-reservation entities, talks about her poetry, prose, and songs; and her efforts to secure the continuance of tribal languages and traditions. Her role as an educator and writer of textbooks is also discussed. Selected poetry is included. (JMM)

  13. SETI Surveys on the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Backus, Peter R.; Kilsdonk, T. N.; ATA Team

    2009-01-01

    The Allen Telescope Array (ATA-42) is a centimeter-wave array of 42 six-meter dishes that allows simultaneous SETI and other radio astronomy projects. In this paper we report on initial SETI observations using several observation and RFI mitigation strategies. We conducted both "targeted” observations of selected stars and "sky survey” observations of areas of the sky. Some observations were done with the SETI project directing the pointing of the array and others were "commensal,” in a direction selected by another project. In both modes, SETI observations used an independent RF tuning and two synthesized beams pointing at stars or positions in the field of view and tuned to the same frequency band. Results of the two SETI observations were compared and used to excise interference. In some observations, each beam had a null positioned at the center of the other beam. In the long term, we plan to observe one million target stars and survey large sections of the galactic plane over the frequency range from 1 GHz to 10 GHz. Much of this work may be done in parallel with other large-scale surveys. The first phase of the ATA was funded through generous grants from the Paul G. Allen Family Foundation. UC Berkeley, the SETI Institute, the National Science Foundation (Grant No. 0540599), Sun Microsystems, Xilinx, Nathan Myhrvold, Greg Papadopoulos, and other corporations and individual donors contributed additional funding.

  14. Remarkable new results for high-energy protons and electrons in the inner Van Allen belt regions

    NASA Astrophysics Data System (ADS)

    Baker, Daniel N.

    2016-04-01

    Early observations indicated that the Earth's Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep 'slot' region largely devoid of particles between them. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location.. Recent Van Allen Probes observations have revealed an unexpected radiation belt morphology, especially at ultrarelativistic kinetic energies (more than several megaelectronvolts). The data show an exceedingly sharp inner boundary for the ultrarelativistic electrons right at L=2.8. Additional, concurrently measured data reveal that this barrier to inward electron radial transport is likely due to scattering by powerful human electromagnetic transmitter (VLF) wave fields. We show that weak, but persistent, wave-particle pitch angle scattering deep inside the Earth's plasmasphere due to manmade signals can act to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate. Inside of this distance, the Van Allen Probes data show that high energy (20 -100 MeV) protons have a double belt structure with a stable peak of flux at L~1.5 and a much more variable belt peaking at L~2.3.

  15. Orion GNC Mitigation Efforts for Van Allen Radiation

    NASA Technical Reports Server (NTRS)

    King, Ellis T.; Jackson, Mark

    2013-01-01

    The Orion Crew Module (CM) is NASA's next generation manned space vehicle, scheduled to return humans to lunar orbit in the coming decade. The Orion avionics and GN&C architectures have progressed through a number of project phases and are nearing completion of a major milestone. The first unmanned test mission, dubbed "Exploration Flight Test One" (EFT-1) is scheduled to launch from NASA Kennedy Space Center late next year and provides the first integrated test of all the vehicle systems, avionics and software. The EFT-1 mission will be an unmanned test flight that includes a high speed re-entry from an elliptical orbit, which will be launched on an expendable launch vehicle (ELV). The ELV will place CM and the ELV upper stage into a low Earth orbit (LEO) for one revolution. After the first LEO, the ELV upper stage will re-ignite and place the combined upper stage/CM into an elliptical orbit whose perigee results in a high energy entry to test CM response in a relatively high velocity, high heating environment. While not producing entry velocities as high as those experienced in returning from a lunar orbit, the trajectory was chosen to provide higher stresses on the thermal protection and guided entry systems, as compared against a lower energy LEO entry. However the required entry geometry with constraints on inclination and landing site result in a trajectory that lingers for many hours in the Van Allen radiation belts. This exposes the vehicle and avionics to much higher levels of high energy proton radiation than a typical LEO or lunar trajectory would encounter. As a result, Van Allen radiation poses a significant risk to the Orion avionics system, and particularly the Flight Control Module (FCM) computers that house the GN&C flight software. The measures taken by the Orion GN&C, Flight Software and Avionics teams to mitigate the risks associated with the Van Allen radiation on EFT-1 are covered in the paper. Background on the Orion avionics subsystem is

  16. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  17. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  18. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  19. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  20. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  1. An Impenetrable Barrier to Ultra-Relativistic Electrons in the Van Allen Radiation Belt

    NASA Astrophysics Data System (ADS)

    Baker, Daniel

    2015-04-01

    Early observations indicated that the Earth's Van Allen belts could be delineated into an inner zone dominated by high energy protons and an outer zone dominated by high energy electrons. Subsequent studies showed that moderate-energy electrons (E≲1 MeV) often populate both zones with a deep "slot" region between them. This two-belt structure was explained as being due to strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary with the inner edge of the outer zone corresponding to the minimum plasmapause location. Recent Van Allen Probes observations have revealed unexpected radiation belt morphology, especially at ultra-relativistic (E > 5 MeV) kinetic energies. Here we discuss an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Concurrent data reveal that this barrier for inward electron radial transport is not due to a physical boundary within Earth's intrinsic magnetic field nor is it likely that scattering by human-generated electromagnetic transmitter wave fields would inhibit inward radial diffusion. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle scattering deep inside the Earth's plasmasphere can conspire to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

  2. Bird watching in the magnetosphere: Global scale observations of near Earth Plasma sheet dynamics through multi-mission and instrument data access

    NASA Astrophysics Data System (ADS)

    Taylor, M. G.; Reeves, G. D.; Turner, D. L.; Kronberg, E. A.; Daly, P. W.; Kletzing, C.; Spence, H.; Walsh, A. P.; Smith, C. W.; MacDowall, R. J.; Claudepierre, S. G.; Fazakerley, A. N.; Escoubet, C.; Masson, A.; Laakso, H. E.

    2013-12-01

    During autumn/fall 2012, the Cluster spacecraft were configured into the largest scale separation ever attempted during the mission so far for a Guest Investigator proposal (C. Foullon) targeting waves and related phenomena at the magnetopause. At this time spacecraft separations were 10,000's km near perigee, equating to ~10-12 hour separation along track. Such separation allowed the observation of the evolution of the near Earth plasma sheet via a series of snap -shots as the spacecraft flew through similar regions of space but separated by hours in time. For a particular event on 12-13 October, the THEMIS and newly launched Van Allen probes, along with ground-based magnetometers observed similar features to those at Cluster, pertaining to inward plasma sheet motion. We present the multi-probe/instrument dataset highlighting the benefit of multi-mission collaboration in studying the dynamics of Earth's magnetosphere.

  3. Freeman Allen: Boston's pioneering physician anesthetist.

    PubMed

    Morris, Samuel D; Morris, Alina J; Rockoff, Mark A

    2014-11-01

    On October 16, 1846 dentist William T. G. Morton successfully demonstrated at the Massachusetts General Hospital that ether could prevent the pain of surgery. For decades afterwards, the administration of anesthesia in the United States was generally relegated to dentists, medical students, junior surgical trainees, or even nonmedical personnel. It was not until the end of the 19th century that a few pioneering physicians began devoting their careers to administering anesthesia to patients, studying ways to make it safer and more effective, and teaching others about its use. One of these individuals was Freeman Allen, who was appointed the first physician anesthetist to the medical staff at the Massachusetts General Hospital and several other major hospitals in Boston. We describe this remarkable man, his contributions to the early development of anesthesiology as a medical specialty, and the true cause of his untimely death. PMID:25329027

  4. The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity

    NASA Astrophysics Data System (ADS)

    Christensen-Dalsgaard, Jørgen; Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita; Si Team

    2011-01-01

    The Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI will enable the development and testing of a predictive dynamo model for the Sun, by observing patterns of surface activity and imaging of the structure and differential rotation of stellar interiors in a population study of Sun-like stars to determine the dependence of dynamo action on mass, internal structure and flows, and time. SI's science focuses on the role of magnetism in the Universe and will revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap, an implementation of the UVOI in the 2006 Astrophysics Strategic Plan, and a NASA Vision Mission ("NASA Space Science Vision Missions" (2008), ed. M. Allen). We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this mission. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/.

  5. Copper-Catalyzed Borylative Cross-Coupling of Allenes and Imines: Selective Three-Component Assembly of Branched Homoallyl Amines.

    PubMed

    Rae, James; Yeung, Kay; McDouall, Joseph J W; Procter, David J

    2016-01-18

    A copper-catalyzed three-component coupling of allenes, bis(pinacolato)diboron, and imines allows regio-, chemo-, and diastereoselective assembly of branched α,β-substituted-γ-boryl homoallylic amines, that is, products bearing versatile amino, alkenyl, and borane functionality. Alternatively, convenient oxidative workup allows access to α-substituted-β-amino ketones. A computational study has been used to probe the stereochemical course of the cross-coupling. PMID:26632675

  6. Copper‐Catalyzed Borylative Cross‐Coupling of Allenes and Imines: Selective Three‐Component Assembly of Branched Homoallyl Amines

    PubMed Central

    Rae, James; Yeung, Kay; McDouall, Joseph J. W.

    2015-01-01

    Abstract A copper‐catalyzed three‐component coupling of allenes, bis(pinacolato)diboron, and imines allows regio‐, chemo‐, and diastereoselective assembly of branched α,β‐substituted‐γ‐boryl homoallylic amines, that is, products bearing versatile amino, alkenyl, and borane functionality. Alternatively, convenient oxidative workup allows access to α‐substituted‐β‐amino ketones. A computational study has been used to probe the stereochemical course of the cross‐coupling. PMID:26632675

  7. Multiband Photometry of the Chromospherically Active & Spotted Binary System IM Peg—the Guide Star for the Gravity Probe B Mission

    NASA Astrophysics Data System (ADS)

    Zellem, Robert; Guinan, Edward F.; Messina, Sergio; Lanza, Antonino F.; Wasatonic, Richard; McCook, George P.

    2010-06-01

    We report on the starspot properties of IM Pegasi—the guide star of the Gravity Probe B (GP-B) satellite. GP-B's mission is to measure two predicted consequences of general relativity—the frame-dragging and geodetic effects—via its extremely precise onboard gyroscopes. However, IM Peg is a chomospherically active binary system with a luminous K2 III primary star showing rotationally modulated (Prot ≈ 24.5 days) light variations from starspots. The starspots can potentially cause problems as GP-B can erroneously interpret a change in starspot coverage (and corresponding shifts in the light center) as the star's movement. This apparent shift can also be exacerbated by possible changes in the light center (photocenter) of the binary system arising from changes in the light balance with the fainter ~1 Msolar (main-sequence early G-type star) component. Since 2000, we have carried out multiband high-precision photoelectric photometry of IM Peg to determine its activity and starspot coverage. Our photometry uses Strömgren uvby intermediate-band filters, VRI filters, and TiO (720/750 nm) narrowband filter sets. Measurements were made relative to nearby comparison and check stars using 0.8 m and 0.25 m telescopes. Analysis of TiO and multiband continuum photometry constrains the starspot areas, temperatures, and surface distributions. The photometry has been modeled using the maximum entropy and Tikhonov regularizations to determine the properties of starspots and to evaluate the effects of changing starspot areas and distributions on the light center of the binary. Our results indicate that IM Peg's activity should not affect the GP-B mission. We also present a study of IM Peg's long-term starspot cycle, which shows evidence of being 20 yr long. Lastly, we have determined the intrinsic (unspotted) brightness of the star to be V mag = 5.62 ± 0.03.

  8. Investigations of wave-particle interactions in the CASSIOPE Enhanced Polar Outflow Probe (e-POP) mission

    NASA Astrophysics Data System (ADS)

    James, Gordon; Knudsen, David; Watt, Clare; Yau, Andrew W.

    The assembly-integration-test phase of the Canadian Space Agency's small-satellite project CASSIOPE was completed in 2009. This spacecraft awaits launch, in about one year's time, into an elliptical earth orbit with 80 inclination, 325-km perigee and 1500-km apogee. The enhanced Polar Outflow Probe (e-POP) complement of eight instruments aboard CASSIOPE includes four that will be applied to investigations of wave-particle interactions (WPIs) in the F and topside regions of the ionosphere: the imaging and rapid ion mass spectrometer (IRM), the suprathermal electron imager (SEI), a triaxial fluxgate magnetometer (MGF) and the radio receiver instrument (RRI). In many WPI experiments, e-POP studies will be abetted by ground-based measurements, for instance, by magnetometers. The investigation of the generation of RF fields linked to the upward motion of ions in polar outflow will be undertaken to understand the role of plasma processes in sustaining the outflow. Electromagnetic wave fields are expected to be present at ion gyrofrequencies when ion conical distributions are being formed. The three-dimensional ion-velocity distributions measured by the IRM, the associated two-dimensional velocity distributions of electrons observed by the SEI, the MGF-supplied magnetic field components of Alfvén waves as one of the putative drivers of the WPIs, and the wave electromagnetic fields detected by the RRI will be combined to improve our understanding of this contributor to ion outflow, and hence of the role of ion outflow in magnetosphere-thermosphere coupling. Data resulting from coordinated operations of the IRM, SEI, MGF and RRI will also be applied to new studies of cusp precipitation. It has been suggested that the acceleration and modula-tion of these precipitating electrons is caused by shear Alfvén waves. The short perpendicular scale of the shear Alfvén waves makes them undetectable by ground-based observatories. In-e vestigations of the role of shear Alfvén waves

  9. 12. Historic American Buildings Survey Allen L. Hubbard, Photographer December ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Historic American Buildings Survey Allen L. Hubbard, Photographer December 1, 1936 CHEST (North room 3rd floor) (SWISS FURNITURE) - Fort Western, Main Building, Bowman Street, Augusta, Kennebec County, ME

  10. 13. Historic American Buildings Survey Allen L. Hubbard, Photographer December ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Historic American Buildings Survey Allen L. Hubbard, Photographer December 1, 1936 CHEST (North room 3rd floor) (SWISS FURNITURE) - Fort Western, Main Building, Bowman Street, Augusta, Kennebec County, ME

  11. 9. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Historic American Buildings Survey Harold Allen, Photographer June 1964 Gilded Relief Decoration, Detail of Frieze at Base of Chancel Arch - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  12. 8. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Historic American Buildings Survey Harold Allen, Photographer June 1964 GILDED RELIEF DECORATION ON FACE OF CHANCEL ARCH - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  13. 4. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Historic American Buildings Survey Harold Allen, Photographer June 1964 AUDITORIUM, FROM BALCONY-- LOOKING NORTHWEST - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  14. 3. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Harold Allen, Photographer June 1964 Auditorium, from Balcony, looking Northeast - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  15. 1. Historic American Buildings Survey Harold Allen, Photographer 31 May ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Harold Allen, Photographer 31 May 1964 WEST (NORMAL AVE.) AND SOUTHEAST (CANALPORT AVE.) ELEVATIONS - Schoenhofen Brewing Company, Powerhouse, 1770 Canalport Avenue, Chicago, Cook County, IL

  16. 3. Historic American Buildings Survey Harold Allen, Photographer 3 May ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Harold Allen, Photographer 3 May 1965 ENTRANCE CANOPY FROM SOUTHWEST - Holy Trinity Russian & Greek Orthodox Church, 1121 North Leavitt Street, Chicago, Cook County, IL

  17. Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: EXTERIOR: WEST (CLARK STREET) AND SOUTH (JACKSON BLVD.) SIDES - U.S. Post Office, Customs House & Sub-Treasury, 218 South Dearborn Street, Chicago, Cook County, IL

  18. Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: CENTRAL HALL, LOOKING ACROSS FROM THE SIXTH FLOOR - U.S. Post Office, Customs House & Sub-Treasury, 218 South Dearborn Street, Chicago, Cook County, IL

  19. Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: CENTRAL HALL, FROM THE SIXTH FLOOR LOOKING NORTHWEST - U.S. Post Office, Customs House & Sub-Treasury, 218 South Dearborn Street, Chicago, Cook County, IL

  20. 2. Historic American Buildings Survey Harold Allen, Photographer 14 June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Harold Allen, Photographer 14 June 1964 TOP THREE FLOORS, MIDDLE BAY, SOUTH (FRONT) ELEVATION - Chicago Criminal Courts Building, 54 West Hubbard Street, Chicago, Cook County, IL

  1. 8. Historic American Buildings Survey Harold Allen, Photographer 24 June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Historic American Buildings Survey Harold Allen, Photographer 24 June 1964 GRAND STAIRWAY, FROM SECOND FLOOR HALL, SHOWING STAINED GLASS WINDOW IN WEST WALL ABOVE LANDING - Francis J. Dewes House, 503 West Wrightwood Avenue, Chicago, Cook County, IL

  2. 6. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey Harold Allen, Photographer June 1964 STAINED GLASS WINDOW, WEST WINDOW IN SOUTH WALL, FROM BALCONY - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  3. A Summing Up. Allen Memorial Art Museum Addition, Oberlin, Ohio

    ERIC Educational Resources Information Center

    Progressive Architecture, 1977

    1977-01-01

    Venturi and Rauch's addition to the Allen Art Museum at Oberlin College is in two separate parts: a loft that houses new facilities for the art department and a gallery for contemporary art. (Author/MLF)

  4. The Guiding Light: Vri/uvby & Tio Photometry Of The Chromospherically Active & Spotted Binary System Im Peg - The Guide-star For The Gravity Probe-b Mission

    NASA Astrophysics Data System (ADS)

    Zellem, Robert; Guinan, E.; Messina, S.; Wasatonic, R.; McCook, G.

    2007-12-01

    We report on the starspot and chromospheric properties of IM Pegasi - the guide star of the Gravity Probe B (GP-B) satellite. GP-B's mission is to measure two predicted consequences of General Relativity - frame-dragging and geodetic effects, via its extremely precise onboard gyroscopes. IM Peg was selected as the mission's guide star as it is not only bright enough to be seen with GP-B's onboard optical telescope but it is also a bright radio source. Thus, ground-based radio telescope observations can easily and accurately correct for IM Peg's motions in space. However, IM Peg is a chomospherically active binary system with a luminous K2 III primary star showing rotationally modulated (Prot 24.5 days) light variations from starspots. The starspots can cause problems as GP-B can erroneously interpret a change in starspot coverage (and corresponding shifts in the light center) as the star's movement. This apparent shift can also be exacerbated by possible changes in the light-center of the binary system arising from changes in the light balance with the fainter dK component. Since 2000 we have carried out multi-band high-precision photoelectric photometry of IM Peg to determine its activity and starspot coverage. Our photometry uses Strömgren uvby filters, VRCIC filters and TiO (719/755 nm ) narrow-band filter sets. Measurements were made relative to neaby comparsion & check stars using a robotic 0.8-m telescope (located in AZ) and 0.25-m telescope (located in PA). The TiO- and multi-band continuum photometry constrains the starspot areas, temperatures and distributions. The photometry is being modeled to determine the effects of changing starspot areas and distributions on the light center of the binary. The results of our analysis and possible impacts on the GP-B Mission will be discussed. This research is supported by NSF/RUI Grants AST- 0507536 and AST- 0507542 which we gratefully acknowledge.

  5. The conversion of allenes to strained three-membered heterocycles.

    PubMed

    Adams, C S; Weatherly, C D; Burke, E G; Schomaker, J M

    2014-05-01

    This article reviews methods for converting allenes to strained, three-membered methylene heterocycles, and also covers the reactivity of these products. Specifically, the synthesis and reactivity of methylene aziridines, allene oxides/spirodiepoxides, methylene silacyclopropanes, methylene phosphiranes, and methylene thiiranes are described, including applications to the synthesis of complex molecules. Due to the primary focus on heterocyclic motifs, the all-carbon analogue of these species (methylene cyclopropane) is only briefly discussed. PMID:24647416

  6. Chemoselective allene aziridination via Ag(I) catalysis.

    PubMed

    Rigoli, Jared W; Weatherly, Cale D; Vo, Brian T; Neale, Samuel; Meis, Alan R; Schomaker, Jennifer M

    2013-01-18

    Allene aziridination generates useful bicyclic methylene aziridine scaffolds that can be flexibly transformed into a range of stereochemically complex and densely functionalized amine-containing stereotriads. The scope of this chemistry has been limited by the poor chemoselectivity that often results when typical dinuclear Rh(II) catalysts are employed with homoallenic carbamates. Herein, Ag(I) catalysts that significantly improve the scope and yield of bicyclic methylene aziridines that can be prepared via allene aziridination are described. PMID:23265391

  7. Chemoselective Allene Aziridination via Ag(I) Catalysis

    PubMed Central

    Rigoli, Jared W.; Weatherly, Cale D.; Vo, Brian T.; Neale, Samuel; Meis, Alan R.

    2015-01-01

    Allene aziridination generates useful bicyclic methylene aziridine scaffolds that can be flexibly transformed into a range of stereochemically complex and densely functionalized amine-containing stereotriads. The scope of this chemistry has been limited by the poor chemoselectivity that often results when typical dinuclear Rh(II) catalysts are employed with homoallenic carbamates. Herein, Ag(I) catalysts that significantly improve the scope and yield of bicyclic methylene aziridines that can be prepared via allene aziridination are described. PMID:23265391

  8. Voices: A Conversation with Allen J. Wilcox.

    PubMed

    Jukic, Anne Marie Z

    2016-09-01

    Allen James Wilcox was born on 30 September 1946 in Columbus, OH. He studied medicine at the University of Michigan, graduated in 1973, and after a rotating internship, he completed a master's degree in maternal and child health (1976) and a PhD in epidemiology (1979) at the University of North Carolina in Chapel Hill. After graduation, he went to work at the National Institute of Environmental Health Sciences (NIEHS, one of the US National Institutes of Health) in Durham, NC, where he has spent his career. He developed a research program in reproductive and perinatal epidemiology, a relatively unexplored area at the time. His studies include the early pregnancy study, which documented the extent of subclinical pregnancy loss in humans and established the fertile days of a woman's menstrual cycle. He served as the Chief of the Epidemiology Branch from 1991 to 2001, and as Editor-in-Chief of the journal EPIDEMIOLOGY from 2001 to 2014. His textbook, Fertility and Pregnancy-An Epidemiologic Perspective, was published by Oxford University Press in 2010. He was elected to the American Epidemiological Society in 1989, and served as its president in 2003. He also served as president of the Society of Pediatric and Perinatal Epidemiological Research (1996) and the president of the Society of Epidemiological Research (1998). He holds adjunct teaching appointments at the University of North Carolina, Harvard University, and the University of Bergen (Norway), which awarded him an honorary doctoral degree in 2008. PMID:27482869

  9. Conductivity Probe

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air.

    The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air.

    The needles on the probe are 15 millimeters (0.6 inch) long.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. 33 CFR 165.T08-0432 - Safety Zone; Waterway Closure, Morgan City-Port Allen Route from Mile Marker 0 to Port Allen Lock.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Morgan City-Port Allen Route from Mile Marker 0 to Port Allen Lock. 165.T08-0432 Section 165.T08-0432... Limited Access Areas Eighth Coast Guard District § 165.T08-0432 Safety Zone; Waterway Closure, Morgan City... Water Way on the Morgan City—Port Allen route from MM 0 to the Port Allen lock. (b) Effective date....

  11. Reactivity and Chemoselectivity of Allenes in Rh(I)-Catalyzed Intermolecular (5 + 2) Cycloadditions with Vinylcyclopropanes: Allene-Mediated Rhodacycle Formation Can Poison Rh(I)-Catalyzed Cycloadditions

    PubMed Central

    2015-01-01

    Allenes are important 2π building blocks in organic synthesis and engage as 2-carbon components in many metal-catalyzed reactions. Wender and co-workers discovered that methyl substituents on the terminal allene double bond counterintuitively change the reactivities of allenes in [Rh(CO)2Cl]2-catalyzed intermolecular (5 + 2) cycloadditions with vinylcyclopropanes (VCPs). More sterically encumbered allenes afford higher cycloadduct yields, and such effects are also observed in other Rh(I)-catalyzed intermolecular cycloadditions. Through density functional theory calculations (B3LYP and M06) and experiment, we explored this enigmatic reactivity and selectivity of allenes in [Rh(CO)2Cl]2-catalyzed intermolecular (5 + 2) cycloadditions with VCPs. The apparent low reactivity of terminally unsubstituted allenes is associated with a competing allene dimerization that irreversibly sequesters rhodium. With terminally substituted allenes, steric repulsion between the terminal substituents significantly increases the barrier of allene dimerization while the barrier of the (5 + 2) cycloaddition is not affected, and thus the cycloaddition prevails. Computation has also revealed the origin of chemoselectivity in (5 + 2) cycloadditions with allene-ynes. Although simple allene and acetylene have similar reaction barriers, intermolecular (5 + 2) cycloadditions of allene-ynes occur exclusively at the terminal allene double bond. The terminal double bond is more reactive due to the enhanced d−π* backdonation. At the same time, insertion of the internal double bond of an allene-yne has a higher barrier as it would break π conjugation. Substituted alkynes are more difficult to insert compared with acetylene, because of the steric repulsion from the additional substituents. This leads to the greater reactivity of the allene double bond relative to the alkynyl group in allene-ynes. PMID:25379606

  12. 76 FR 36318 - Safety Zone; Waterway Closure, Morgan City-Port Allen Route From Mile Marker 0 to Port Allen Lock

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Waterway Closure, Morgan City-Port Allen..., design, or operation; test methods; sampling procedures; and related management systems practices) that...; Waterway Closure, Morgan City-Port Allen Route from Mile Marker 0 to Port Allen Lock. (a) Location....

  13. Biosynthesis of allene oxides in Physcomitrella patens

    PubMed Central

    2012-01-01

    Background The moss Physcomitrella patens contains C18- as well as C20-polyunsaturated fatty acids that can be metabolized by different enzymes to form oxylipins such as the cyclopentenone cis(+)-12-oxo phytodienoic acid. Mutants defective in the biosynthesis of cyclopentenones showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis. The initial step in this biosynthetic route is the conversion of a fatty acid hydroperoxide to an allene oxide. This reaction is catalyzed by allene oxide synthase (AOS) belonging as hydroperoxide lyase (HPL) to the cytochrome P450 family Cyp74. In this study we characterized two AOS from P. patens, PpAOS1 and PpAOS2. Results Our results show that PpAOS1 is highly active with both C18 and C20-hydroperoxy-fatty acid substrates, whereas PpAOS2 is fully active only with C20-substrates, exhibiting trace activity (~1000-fold lower kcat/KM) with C18 substrates. Analysis of products of PpAOS1 and PpHPL further demonstrated that both enzymes have an inherent side activity mirroring the close inter-connection of AOS and HPL catalysis. By employing site directed mutagenesis we provide evidence that single amino acid residues in the active site are also determining the catalytic activity of a 9-/13-AOS – a finding that previously has only been reported for substrate specific 13-AOS. However, PpHPL cannot be converted into an AOS by exchanging the same determinant. Localization studies using YFP-labeled AOS showed that PpAOS2 is localized in the plastid while PpAOS1 may be found in the cytosol. Analysis of the wound-induced cis(+)-12-oxo phytodienoic acid accumulation in PpAOS1 and PpAOS2 single knock-out mutants showed that disruption of PpAOS1, in contrast to PpAOS2, results in a significantly decreased cis(+)-12-oxo phytodienoic acid formation. However, the knock-out mutants of neither PpAOS1 nor PpAOS2 showed reduced fertility, aberrant sporophyte morphology or interrupted sporogenesis. Conclusions Our study

  14. The Pioneer Venus Missions.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Mountain View, CA. Ames Research Center.

    This document provides detailed information on the atmosphere and weather of Venus. This pamphlet describes the technological hardware including the probes that enter the Venusian atmosphere, the orbiter and the launch vehicle. Information is provided in lay terms on the mission profile, including details of events from launch to mission end. The…

  15. Ultrarelativistic electrons in the Van Allen belts: RPS observations and Geant4 simulations

    NASA Astrophysics Data System (ADS)

    Looper, M. D.; Mazur, J. E.; O'Brien, T. P., III; Blake, J. B.; George, J. S.

    2015-12-01

    The Relativistic Proton Spectrometer (RPS) aboard the Van Allen Probes spacecraft is designed to measure protons from about 60 MeV to multiple GeV, but it is also sensitive to electrons above several MeV. Its Cherenkov subsystem provides energy resolution for protons above a few hundred MeV, and electrons at extremely high energies, around 50 MeV and above, can also produce high levels of Cherenkov light. While mapping protons in the inner Van Allen Belt with RPS, Mazur et al. (Fall 2014 AGU meeting, paper SM22A-02) observed a concentration of particle events around L = 2 with Cherenkov light corresponding to protons at energies well above the limit for stable trapping there. We present a preliminary analysis that shows that the patterns of the Cherenkov light distribution are consistent with these particle events instead being caused by electrons at energies of at least several tens of MeV. This energy range is well above that expected from magnetospheric energization, even by a violent event like the March 1991 shock, which injected electrons peaked around 15 MeV (Looper et al., GRL 1994, doi:10.1029/94GL01586). We discuss the possibility that these electrons are instead due to the decay of pions and muons produced by cosmic-ray interactions with the atmosphere, with a characteristic energy set by the pion rest mass of 140 MeV.

  16. Impacts of intense inward and outward ULF wave radial diffusion on the Van Allen belts

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Ozeke, Louis; Rae, I. Jonathan; Murphy, Kyle

    2016-07-01

    During geomagnetic storms, the power in ultra-low frequency (ULF) waves can be orders of magnitude larger than that predicted by statistics determined from an entire solar cycle. This is especially true during the main phase and early recovery phase. These periods of enhanced storm-time ULF wave power can have significant impacts on the morphology and structure of the Van Allen belts. Either fast inward or outward radial diffusion can result, depending on the profiles of the electron phase space density and the outer boundary condition at the edge of the belts. Small changes in the time sequence of powerful ULF waves, and the time sequence of any magnetopause shadowing or the recovery of plamasheet sources relative to the ULF wave occurrence, have a remarkable impact on the resulting structure of the belts. The overall impact of the enhanced ULF wave power is profound, but the response can be very different depending on the available source flux in the plasmasheet. We review these impacts by examining ultra-relativistic electron dynamics during seemingly different storms during the Van Allen Probe era, including during the Baker et al. third radiation belt, and show the observed behaviour can be largely explained by differences in the time sequence of events described above.

  17. Clarence Allen talks about the responsibilities in earthquake prediction

    USGS Publications Warehouse

    Spall, H.

    1978-01-01

    Dr. Clarence R. Allen is professor of geology and geophysics at the California Institute of Technology. He has been a member of advisory panels to the Executive Office of the President, National Academy of Sciences, National Science Foundation, U.S Geological Survey, UNESCO, California State Mining and Geology Board, and the California Department of Water Resources. Dr. Allen has been President of both the Geological Society of America and the Seismological Society of America (SSA). The title of this interview is based on his presidential address to the SSA in 1976. 

  18. Exo-C: a Probe-Scale Space Mission to Directly Image and Spectroscopically Characterize Exoplanetary Systems Using an Internal Coronagraph

    NASA Technical Reports Server (NTRS)

    Stapelfeldt, Karl R.; Brenner, Michael P.; Warfield, Keith R.; Dekens, Frank G.; Belikov, Ruslan; Brugarolas, Paul B.; Bryden, Geoffrey; Cahoy, Kerri L.; Chakrabarti, Supriya; Dubovitsky, Serge; Effinger, Robert T.; Hirsch, Brian; Kissil, Andrew; Krist, John E.; Lang, Jared J.; Marley, Mark S.; McElwain, Michael W.; Meadows, Victoria S.; Nissen, Joel; Oseas, Jeffrey M.; Serabyn, Eugene; Sunada, Eric; Trauger, John T.; Unwin, Stephen C.

    2014-01-01

    "Exo-C" is NASA's first community study of a modest aperture space telescope designed for high contrast observations of exoplanetary systems. The mission will be capable of taking optical spectra of nearby exoplanets in reflected light, discover previously undetected planets, and imaging structure in a large sample of circumstellar disks. It will obtain unique science results on planets down to super-Earth sizes and serve as a technology pathfinder toward an eventual flagship-class mission to find and characterize habitable exoplanets. We present the mission/payload design and highlight steps to reduce mission cost/risk relative to previous mission concepts. At the study conclusion in 2015, NASA will evaluate it for potential development at the end of this decade. Keywords: Exoplanets, high contrast imaging, optical astronomy, space mission concepts

  19. Astronauts Allen and Gemar during extravehicular activity (EVA) training in CCT

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronauts Charles D. (Sam) Gemar, and Andrew M. Allen participate in a training exercise at JSC's Crew Compartment Trainer (CCT), located in the Space Vehicle Mockup Facility. Gemar sits inside the airlock as Allen reviews procedures for EVA.

  20. Galileo Probe Battery System

    NASA Technical Reports Server (NTRS)

    Dagarin, B. P.; Taenaka, R. K.; Stofel, E. J.

    1997-01-01

    The conclusions of the Galileo probe battery system are: the battery performance met mission requirements with margin; extensive ground-based and flight tests of batteries prior to probe separation from orbiter provided good prediction of actual entry performance at Jupiter; and the Li-SO2 battery was an important choice for the probe's main power.

  1. Compressive Acceleration of Solar Energetic Particles within Coronal Mass Ejections: Observations and Theory Relevant to the Solar Probe Plus and Solar Orbiter Missions

    NASA Astrophysics Data System (ADS)

    Roelof, E. C.

    2015-12-01

    observational technique by which (divV) may be extracted directly from coronograph white-light movies of out-going CMEs, thus offering observational closure of the new theory for SEP acceleration/injection that should be relevant to the Solar Probe Plus and Solar Orbiter missions.

  2. Gold(I)-Catalyzed Hydroarylation of Allenes with Indoles

    PubMed Central

    Toups, Kristina L.; Liu, Gordon T.; Widenhoefer, Ross A.

    2010-01-01

    Reaction of a monosubstituted, 1,3-disubstituted, or tetrasubstituted allene with various indoles catalyzed by a 1:1 mixture of a gold(I) N-heterocyclic carbene complex and AgOTf at room temperature leads to hydroarylation with formation of 3-allyl-indoles in modest to good yield. PMID:20305794

  3. Gold(I)-Catalyzed Hydroarylation of Allenes with Indoles

    PubMed Central

    Toups, Kristina L.; Liu, Gordon T.; Widenhoefer, Ross A.

    2009-01-01

    Reaction of a monosubstituted, 1,3-disubstituted, or tetrasubstituted allene with various indoles catalyzed by a 1:1 mixture of a gold(I) N-heterocyclic carbene complex and AgOTf at room temperature leads to hydroarylation with formation of 3-allyl-indoles in modest to good yield. PMID:17428061

  4. 5. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey Harold Allen, Photographer June 1964 TRIPLE STAINED GLASS WINDOWS AND COLUMN SUPPORTING BALCONY (EAST WINDOWS IN SOUTH WALL OF MAIN FLOOR OF AUDITORIUM) - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  5. Exo-C: a probe-scale space mission to directly image and spectroscopically characterize exoplanetary systems using an internal coronagraph

    NASA Astrophysics Data System (ADS)

    Stapelfeldt, Karl R.; Brenner, Michael P.; Warfield, Keith R.; Dekens, Frank G.; Belikov, Ruslan; Brugarolas, Paul B.; Bryden, Geoffrey; Cahoy, Kerri L.; Chakrabarti, Supriya; Dubovitsky, Serge; Effinger, Robert T.; Hirsch, Brian; Kissil, Andrew; Krist, John E.; Lang, Jared J.; Marley, Mark S.; McElwain, Michael W.; Meadows, Victoria S.; Nissen, Joel; Oseas, Jeffrey M.; Serabyn, Eugene; Sunada, Eric; Trauger, John T.; Unwin, Stephen C.

    2014-08-01

    "Exo-C" is NASA's first community study of a modest aperture space telescope designed for high contrast observations of exoplanetary systems. The mission will be capable of taking optical spectra of nearby exoplanets in reflected light, discover previously undetected planets, and imaging structure in a large sample of circumstellar disks. It will obtain unique science results on planets down to super-Earth sizes and serve as a technology pathfinder toward an eventual flagship-class mission to find and characterize habitable exoplanets. We present the mission/payload design and highlight steps to reduce mission cost/risk relative to previous mission concepts. At the study conclusion in 2015, NASA will evaluate it for potential development at the end of this decade.

  6. The Unique Capabilities of the Allen Telescope Array for Pulsar Timing and Gravitational Wave Detection

    NASA Astrophysics Data System (ADS)

    McLaughlin, Maura

    2011-01-01

    Since their discovery in 1982, millisecond pulsars have served as exquisite probes of fundamental physics. I will discuss the most transformative current application of millisecond pulsars: the direct detection of gravitational waves. Timing an array of pulsars could result in the detection of a stochastic background of gravitational waves, most likely resulting from an ensemble of supermassive black hole binaries. The unique capabilities of the Allen Telescope Array (ATA) will make it a very important resource for this experiment. The multi-wavelength coverage will increase sensitivity and enable optimal removal of interstellar propagation affects and the flexibility of scheduling afforded by commensal observing will increase the number of sources times and the cadence at which we can observe each source. I will discuss how these properties complement existing facilities and how including the ATA will increase the sensitivity of the international pulsar timing array.

  7. STEREO Mission Design Implementation

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.; Dunham, David W.; Sharer, Peter J.; Hunt, Jack W.; Ray, J. Courtney; Shapiro, Hongxing S.; Ossing, Daniel A.; Eichstedt, John E.

    2007-01-01

    STEREO (Solar-TErrestrial RElations Observatory) is the third mission in the Solar Terrestrial Probes program (STP) of the National Aeronautics and Space Administration (NASA) Science Mission Directorate Sun-Earth Connection theme. This paper describes the successful implementation (lunar swingby targeting) of the mission following the first phasing orbit to deployment into the heliocentric mission orbits following the two lunar swingbys. The STEREO Project had to make some interesting trajectory decisions in order to exploit opportunities to image a bright comet and an unusual lunar transit across the Sun.

  8. Day 4 activities in the MOCR during STS-5 mission

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Day 4 activities in the mission operations control room (MOCR) during STS-5 mission. Scott Thomas, a freshman at Utah State University, watches the television monitor in front of him in the mission operations control room (MOCR) at JSC's mission control center. Astronaut Joseph P. Allen, STS-5 mission specialist, conducts an experiment - a study of convection in zero gravity - onboard the Columbia. The experiment is part of the student experiments program and was conceived by Thomas. Also at the payloads console with Thomas is Robert M. Kelso, of the Flight Operations Directorate. The stuffed mascot for the payloads team, a kangaroo, sits atop the payloads team console.

  9. Observations of a solar storm from the stratosphere: The BARREL Mission

    NASA Astrophysics Data System (ADS)

    Halford, Alexa

    2016-07-01

    During the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) second campaign, BARREL observed with a single primary instrument, a 3"x3" NaI spectrometer measuring 20 keV - 10 MeV X-rays [Woodger et al 2015 JGR], portions of an entire solar storm. This very small event, in terms of geomagnetic activity, or one of the largest of the current solar cycle, in terms of solar energetic particle events, has given us a very clear set of observations of the response of the day side magnetosphere to the arrival of an interplanetary coronal mass ejection shock. The BARREL mission of opportunity working in tandem with the Van Allen Probes was designed to study the loss of radiation belt electrons to the ionosphere and upper atmosphere. However BARREL is able to see X-rays from a multitude of sources. During the second campaign, the Sun produced, and BARREL observed, an X-class flare [McGregor et al in prep.]. This was followed by BARREL observations of X-rays, gamma-rays, and directly injected protons from the solar energetic particle (SEP) event associated with the eruption from the Sun while simultaneously the Van Allen Probes observed the SEP protons in the inner magnetosphere [Halford et al 2016 submitted JGR]. Two days later the shock generated by the interplanetary coronal mass ejection (ICME-shock) hit the Earth while BARREL was in conjunction with the Van Allen Probes and GOES [Halford et al 2015 JGR]. Although this was a Mars directed CME and the Earth only received a glancing blow [Möstl et al 2015 Nat. Commun., Mays et al 2015 ApJ], the modest compression led to the formation of ultra low frequency (ULF) waves, electromagnetic ion cyclotron (EMIC) waves, and very low frequency (VLF) whistler mode waves [Halford and Mann 2016 submitted to JGR]. The combination of these waves and the enhancement of the local particle population led to precipitation of electrons remotely observed by BARREL. This was not a Halloween, Bastille Day, or one of the now

  10. Isomer-specific combustion chemistry in allene and propyne flames

    SciTech Connect

    Hansen, Nils; Miller, James A.; Westmoreland, Phillip R.; Kasper, Tina; Kohse-Hoeinghaus, Katharina; Wang, Juan; Cool, Terrill A.

    2009-11-15

    A combined experimental and modeling study is performed to clarify the isomer-specific combustion chemistry in flames fueled by the C{sub 3}H{sub 4} isomers allene and propyne. To this end, mole fraction profiles of several flame species in stoichiometric allene (propyne)/O{sub 2}/Ar flames are analyzed by means of a chemical kinetic model. The premixed flames are stabilized on a flat-flame burner under a reduced pressure of 25 Torr (=33.3 mbar). Quantitative species profiles are determined by flame-sampling molecular-beam mass spectrometry, and the isomer-specific flame compositions are unraveled by employing photoionization with tunable vacuum-ultraviolet synchrotron radiation. The temperature profiles are measured by OH laser-induced fluorescence. Experimental and modeled mole fraction profiles of selected flame species are discussed with respect to the isomer-specific combustion chemistry in both flames. The emphasis is put on main reaction pathways of fuel consumption, of allene and propyne isomerization, and of isomer-specific formation of C{sub 6} aromatic species. The present model includes the latest theoretical rate coefficients for reactions on a C{sub 3}H{sub 5} potential [J.A. Miller, J.P. Senosiain, S.J. Klippenstein, Y. Georgievskii, J. Phys. Chem. A 112 (2008) 9429-9438] and for the propargyl recombination reactions [Y. Georgievskii, S.J. Klippenstein, J.A. Miller, Phys. Chem. Chem. Phys. 9 (2007) 4259-4268]. Larger peak mole fractions of propargyl, allyl, and benzene are observed in the allene flame than in the propyne flame. In these flames virtually all of the benzene is formed by the propargyl recombination reaction. (author)

  11. STEREO Mission Design

    NASA Technical Reports Server (NTRS)

    Dunham, David W.; Guzman, Jose J.; Sharer, Peter J.; Friessen, Henry D.

    2007-01-01

    STEREO (Solar-TErestrial RElations Observatory) is the third mission in the Solar Terrestrial Probes program (STP) of the National Aeronautics and Space Administration (NASA). STEREO is the first mission to utilize phasing loops and multiple lunar flybys to alter the trajectories of more than one satellite. This paper describes the launch computation methodology, the launch constraints, and the resulting nine launch windows that were prepared for STEREO. More details are provided for the window in late October 2006 that was actually used.

  12. Syntheses of allene-modified derivatives of peridinin toward elucidation of the effective role of the allene function in high energy transfer efficiencies in photosynthesis†

    PubMed Central

    Kajikawa, Takayuki; Aoki, Kazuyoshi; Singh, Ram Shanker; Iwashita, Takashi; Kusumoto, Toshiyuki; Frank, Harry A.; Hashimoto, Hideki

    2013-01-01

    Peridinin is known as the main light-harvesting pigment in photosynthesis in the sea and exhibits exceptionally high energy transfer efficiencies to chlorophyll a. This energy transfer efficiency is thought to be related to the intricate structure of peridinin, which possesses allene and ylidenbutenolide functions in the polyene backbone. There are, however, no studies on the relationship between the structural features of peridinin and its super ability for energy transfer. We then focused on the subjects of why peridinin possesses a unique allene group and how the allene function plays a role in the exceptionally high energy transfer. Toward elucidation of the exact role of the allene function, we now describe the syntheses of three relatively unstable allene-modified derivatives of peridinin along with the results of the Stark spectroscopy of peridinin and the synthesized peridinin derivatives. PMID:19707676

  13. Calibration of Langmuir probes against microwaves and plasma oscillation probes

    NASA Astrophysics Data System (ADS)

    Chen, Francis F.; Evans, John D.; Zawalski, Wade

    2012-10-01

    The use of Langmuir probes for measuring plasma density is subject to uncertainty because the theories commonly used to interpret the data give widely differing results. This is especially troublesome in partially ionized plasmas used, for instance, in the semiconductor industry, since no existing theory adequately treats the case when there are a few collisions between ions and neutral atoms. In this work, plasma densities measured by microwave interferometry and plasma-oscillation probes are compared with those from probe data analyzed with Langmuir's orbital motion limited (OML) theory, the Allen-Boyd-Reynolds (ABR) theory and the Bernstein-Rabinowitz-Laframboise (BRL) theory. It is found that ABR underestimates and BRL overestimates the density, the problems being the neglect of ion orbiting in ABR and the effect of ion-neutral collisions in BRL. The best theory is either OML or the geometric mean between the ABR and BRL results. For thicker probes, other methods are suggested.

  14. The Cluster II mission: recent observations and instrument calibrations

    NASA Astrophysics Data System (ADS)

    Elena, Kronberg

    2016-07-01

    For over 15 years, the Cluster mission passes through Earth's radiation belts at least once every two days for several hours, measuring the energetic electron intensity at energies from 30 to 400 keV. This vast amount of data has previously been considered as rather useless due to contamination by penetrating energetic particles (protons at >100 keV and electrons at >400 keV). In this study, we assess the efficiency with which aluminum shielding of RAPID/IES detector filters out contaminating high-energy electrons and protons. We base our estimation on the analysis of experimental data and a radiation transport code (Geant4). In our simulations, we use the incident particle energy distribution of the AE9/AP9 radiation belt models. We identify the Roederer L-values and energy channels that should be used with caution and show examples of misinterpreting the data. Comparison of the data with electron and proton observations from the Van Allen Probes ECT/MagEis indicates that the subtraction of proton intensities at energies ~230-630 keV from the IES electron data cleans the data from the proton contamination. We show that the data from this detector measured in the radiation belts is still useful for many scientific applications. This is valuable as it provides one of the longest available radiation belt data sets.

  15. Storm-time response of the Van Allen radiation belts organized by the large-scale solar wind drivers, energy and distance

    NASA Astrophysics Data System (ADS)

    Hietala, Heli; Kilpua, Emilia; Turner, Drew

    2016-04-01

    We study the response of the Van Allen radiation belts during geomagnetic storms. A combination of the long-term geosynchronous observations from GOES (> 2.5 MeV) and energy (tens of keV to 2 MeV) and L-shell (2.5 < L < 6.0) resolved Van Allen Probe observations are used. We demonstrate that the radiation belt response (depletion, no-change, increase) is organized by the large-scale solar wind driver (coronal mass ejection ejecta/sheath, slow-fast stream interface region, fast stream) and that the response is highly dependent on both the electron energy and the L-shell. In addition, we show detailed Van Allen Probe observations from two geomagnetic storms that occurred during two consecutive Carrington rotations of the solar maximum year 2015. Both of these storms involved a slow-fast stream interaction region and a fast stream originating from the same coronal hole. However, the first storm also included a large-scale coronal mass ejection. We study in particular how the added presence of this coronal mass ejection affected the dynamics of the radiation belts.

  16. Phoenix Conductivity Probe

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows thermal and electrical conductivity probe on NASA's Phoenix Mars Lander's Robotic Arm.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  17. Synergistic Kinetic Resolution and Asymmetric Propargyl Claisen Rearrangement for the Synthesis of Chiral Allenes.

    PubMed

    Liu, Yangbin; Liu, Xiaohua; Hu, Haipeng; Guo, Jing; Xia, Yong; Lin, Lili; Feng, Xiaoming

    2016-03-14

    The asymmetric propargyl Claisen rearrangement provides a convenient entry to chiral allene motifs. Herein, we describe the development of a kinetic resolution and asymmetric rearrangement of racemic propargyl vinyl ethers. This transformation afforded chiral allene products along with the enantiomerically enriched substrate in good yields with excellent diastereo- and enantioselectivity. The complete chirality transfer and facially selective rearrangement enabled the simultaneous construction of an axially chiral allenic unit and a quaternary carbon stereocenter. PMID:26889758

  18. Planetary cubesats - mission architectures

    NASA Astrophysics Data System (ADS)

    Bousquet, Pierre W.; Ulamec, Stephan; Jaumann, Ralf; Vane, Gregg; Baker, John; Clark, Pamela; Komarek, Tomas; Lebreton, Jean-Pierre; Yano, Hajime

    2016-07-01

    Miniaturisation of technologies over the last decade has made cubesats a valid solution for deep space missions. For example, a spectacular set 13 cubesats will be delivered in 2018 to a high lunar orbit within the frame of SLS' first flight, referred to as Exploration Mission-1 (EM-1). Each of them will perform autonomously valuable scientific or technological investigations. Other situations are encountered, such as the auxiliary landers / rovers and autonomous camera that will be carried in 2018 to asteroid 1993 JU3 by JAXA's Hayabusas 2 probe, and will provide complementary scientific return to their mothership. In this case, cubesats depend on a larger spacecraft for deployment and other resources, such as telecommunication relay or propulsion. For both situations, we will describe in this paper how cubesats can be used as remote observatories (such as NEO detection missions), as technology demonstrators, and how they can perform or contribute to all steps in the Deep Space exploration sequence: Measurements during Deep Space cruise, Body Fly-bies, Body Orbiters, Atmospheric probes (Jupiter probe, Venus atmospheric probes, ..), Static Landers, Mobile landers (such as balloons, wheeled rovers, small body rovers, drones, penetrators, floating devices, …), Sample Return. We will elaborate on mission architectures for the most promising concepts where cubesat size devices offer an advantage in terms of affordability, feasibility, and increase of scientific return.

  19. NASA mission planning for space nuclear power

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.; Schnyer, A. D.

    1991-01-01

    An evaluation is conducted of those aspects of the Space Exploration Initiative which stand to gain from the use of nuclear powerplants. Low-power, less than 10 kW(e) missions in question encompass the Comet Rendezvous Asteroid Flyby, the Cassini mission to Saturn, the Mars Network mission, a solar probe, the Mars Rover Sample Return mission, the Rosetta comet nucleus sample return mission, and an outer planets orbiter/probe. Reactor power yielding 10-100 kW(e) can be used by advanced rovers and initial lunar and Martian outposts, as well as Jovian and Saturnian grand tours and sample-return missions.

  20. A computational model for the dimerization of allene.

    PubMed

    Skraba, Sarah L; Johnson, Richard P

    2012-12-21

    Computations at the CCSD(T)/6-311+G(d,p)//B3LYP/6-311+G(d,p) level of theory support long-held beliefs that allene dimerization to 1,2-dimethylenecyclobutane proceeds through diradical intermediates rather than a concerted (π)2(s) + (π)2(a) mechanism. Two diastereomeric transition states with orthogonal and skew geometries have been located for C2-C2 dimerization of allene, with predicted barriers of 34.5 and 40.3 kcal/mol, respectively. In dimerization, the outward-facing ligands rotate in a sense opposite to the forming C-C bond. Both transition states lead to nearly orthogonal (D(2)) singlet bisallyl (or tetramethyleneethane) diradical. This diradical has a barrier to planarization of 3.2 kcal/mol through a planar D(2h) geometry and a barrier to methylene rotation of 14.3 kcal/mol. Bisallyl diradical closes through one of four degenerate paths by a conrotatory motion of the methylene groups with a predicted barrier of 15.7 kcal/mol. The low barrier to planarization of bisallyl, and similar barriers for methylene rotation and conrotatory closure are consistent with a stepwise dimerization process which can still maintain stereochemical elements of reactants. These computations support the observation that racemic 1,3-disubstituted allenes, with access to an orthogonal transition state which minimizes steric strain, will dimerize more readily than enantiopure materials and by a mechanism that preferentially bonds M and P enantiomers. PMID:23198916

  1. Neuroinformatics of the Allen Mouse Brain Connectivity Atlas.

    PubMed

    Kuan, Leonard; Li, Yang; Lau, Chris; Feng, David; Bernard, Amy; Sunkin, Susan M; Zeng, Hongkui; Dang, Chinh; Hawrylycz, Michael; Ng, Lydia

    2015-02-01

    The Allen Mouse Brain Connectivity Atlas is a mesoscale whole brain axonal projection atlas of the C57Bl/6J mouse brain. Anatomical trajectories throughout the brain were mapped into a common 3D space using a standardized platform to generate a comprehensive and quantitative database of inter-areal and cell-type-specific projections. This connectivity atlas has several desirable features, including brain-wide coverage, validated and versatile experimental techniques, a single standardized data format, a quantifiable and integrated neuroinformatics resource, and an open-access public online database (http://connectivity.brain-map.org/). Meaningful informatics data quantification and comparison is key to effective use and interpretation of connectome data. This relies on successful definition of a high fidelity atlas template and framework, mapping precision of raw data sets into the 3D reference framework, accurate signal detection and quantitative connection strength algorithms, and effective presentation in an integrated online application. Here we describe key informatics pipeline steps in the creation of the Allen Mouse Brain Connectivity Atlas and include basic application use cases. PMID:25536338

  2. Hovering and forward flight energetics in Anna's and Allen's hummingbirds.

    PubMed

    Clark, Christopher James; Dudley, Robert

    2010-01-01

    Aerodynamic theory predicts that the mechanical costs of flight are lowest at intermediate flight speeds; metabolic costs of flight should trend similarly if muscle efficiency is constant. We measured metabolic rates for nine Anna's hummingbirds (Calypte anna) and two male Allen's hummingbirds (Selasphorus sasin) feeding during flight from a free-standing mask over a range of airspeeds. Ten of 11 birds exhibited higher metabolic costs during hovering than during flight at intermediate airspeeds, whereas one individual exhibited comparable costs at hovering and during forward flight up to speeds of approximately 7 m s(-1). Flight costs of all hummingbirds increased at higher airspeeds. Relative to Anna's hummingbirds, Allen's hummingbirds exhibited deeper minima in the power curve, possibly due to higher wing loadings and greater associated costs of induced drag. Although feeding at a mask in an airstream may reduce body drag and, thus, the contributions of parasite power to overall metabolic expenditure, these results suggest that hummingbird power curves are characterized by energetic minima at intermediate speeds relative to hovering costs. PMID:20455711

  3. Ion currents to cylindrical Langmuir probes for finite ion temperature values: Theory

    SciTech Connect

    Ballesteros, J.; Palop, J.I.F.; Colomer, V.; Hernandez, M.A.

    1995-12-31

    As it is known, the experimental ion currents to a cylindrical Langmuir probe fit quite well to the radial motion theory, developed by Allen, Boyd and Reynolds (ABR Model) and generalized by Chen for the cylindrical probe case. In this paper, we are going to develop a generalization of the ABR theory, taking into account the influence of a finite ion temperature value.

  4. Modified Mason-Allen Suture Bridge Technique: A New Suture Bridge Technique with Improved Tissue Holding by the Modified Mason-Allen Stitch

    PubMed Central

    Lee, Bong Gun; Cho, Nam Su

    2012-01-01

    We present a new method of suture bridge technique for medial row fixation using a modified Mason-Allen stitch instead of a horizontal mattress. Medial row configuration of the technique is composed of the simple stitch limb and the modified Mason-Allen stitch limb. The limbs are passed through the tendon by a shuttle relay. The simple stitch limb passes the cuff once and the modified Mason-Allen stitch limb passes three times which creates a rip stop that prevents tendon pull-out. In addition, the Mason-Allen suture bridge configuration is basically a knotless technique which has an advantage of reducing a possibility of strangulation of the rotator cuff tendon, impingement or irritation that may be caused by knot. PMID:22949957

  5. Investigation of solar wind driver effects on electron acceleration and loss in the outer Van Allen belt

    NASA Astrophysics Data System (ADS)

    Katsavrias, Christos; Li, Wen; Daglis, Ioannis A.; Papadimitriou, Constantinos; Georgiou, Marina; Dimitrakoudis, Stavros

    2016-07-01

    We have investigated the response of the outer Van Allen belt electrons to various types of solar wind and internal magnetospheric forcing - in particular to Interplanetary Coronal Mass Ejections (ICMEs), to High Speed Streams (HSS), to geospace magnetic storms of different intensities and to intense magnetospheric substorms. We have employed multi-point particle and field observations in the inner magnetosphere (both in-situ and through ground-based remote sensing), including the Cluster, THEMIS, Van Allen Probes and GOES constellations, the XMM and INTEGRAL spacecraft, and the CARISMA and IMAGE ground magnetometer arrays. The data provide a broad range of particle energies and a wide radial and azimuthal spatial coverage. Observations show that losses of equatorially mirroring electrons are primarily caused by magnetopause shadowing which in turn is achieved by outward diffusion driven by Pc5 ULF waves. Chorus wave activity, on the other hand, seems to be responsible for electron enhancements in the outer radiation belt even in the presence of pronounced outward diffusion.

  6. How quickly, how deeply, and how strongly can dynamical outer boundary conditions impact Van Allen radiation belt morphology?

    NASA Astrophysics Data System (ADS)

    Mann, Ian R.; Ozeke, Louis G.

    2016-06-01

    Here we examine the speed, strength, and depth of the coupling between dynamical variations of ultrarelativistic electron flux at the outer boundary and that in the heart of the outer radiation belt. Using ULF wave radial diffusion as an exemplar, we show how changing boundary conditions can completely change belt morphology even under conditions of identical wave power. In the case of ULF wave radial diffusion, the temporal dynamics of a new source population or a sink of electron flux at the outer plasma sheet boundary can generate a completely opposite response which reaches deep into the belt under identical ULF wave conditions. Very significantly, here we show that such coupling can occur on timescales much faster than previously thought. We show that even on timescales ~1 h, changes in the outer boundary electron population can dramatically alter the radiation belt flux in the heart of the belt. Importantly, these flux changes can at times occur on timescales much faster than the L shell revisit time obtained from elliptically orbiting satellites such as the Van Allen Probes. We underline the importance of such boundary condition effects when seeking to identify the physical processes which explain the dominant behavior of the Van Allen belts. Overall, we argue in general that the importance of temporal changes in the boundary conditions is sometimes overlooked in comparison to the pursuit of (ever) increasingly accurate estimates of wave power and other wave properties used in empirical representations of wave transport and diffusion rates.

  7. Q & A with Ed Tech Leaders: Interview with Michael W. Allen

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.

    2014-01-01

    Michael W. Allen, the Chairman and CEO of Allen Interactions, is an architect of interactive multimedia learning and is recognized for his many insights, inventions, and presentations. With over 50 years of experience in e-learning, both in academic and corporate settings, he is known for his role in creating Authorware and overseeing the work of…

  8. Primary Beam and Dish Surface Characterization at the Allen Telescope Array by Radio Holography

    NASA Astrophysics Data System (ADS)

    Harp, G. R.; Ackermann, R. F.; Nadler, Z. J.; Blair, Samantha K.; Davis, M. M.; Wright, M. C. H.; Forster, J. R.; Deboer, D. R.; Welch, W. J.; Atkinson, Shannon; Backer, D. C.; Backus, P. R.; Barott, William; Bauermeister, Amber; Blitz, Leo; Bock, D. C.-J.; Bower, Geoffrey C.; Bradford, Tucker; Cheng, Calvin; Croft, Steve; Dexter, Matt; Dreher, John; Engargiola, Greg; Fields, E. D.; Heiles, Carl; Helfer, Tamara; Jordan, Jane; Jorgensen, Susan; Kilsdonk, Tom; Gutierrez-Kraybill, Colby; Keating, Garrett; Law, Casey; Lugten, John; MacMahon, D. H. E.; McMahon, Peter; Milgrome, Oren; Siemion, Andrew; Smolek, Ken; Thornton, Douglas; Pierson, Tom; Randall, Karen; Ross, John; Shostak, Seth; Tarter, J. C.; Urry, Lynn; Werthimer, Dan; Williams, Peter K. G.; Whysong, David

    2011-06-01

    The Allen Telescope Array (ATA) is a cm-wave interferometer in California, comprising 42 antenna elements with 6-m diameter dishes. We characterize the antenna optical accuracy using two-antenna interferometry and radio holography. The distortion of each telescope relative to the average is small, with RMS differences of 1% of beam peak value. Holography provides images of dish illumination, characterizing as-built mirror surfaces. Maximal distortions across ~ 2 meter lengths appear to result from mounting stresses or solar radiation. Experimental RMS errors are 0.7 mm at night and 3 mm under worst-case solar illumination. For frequencies 4, 10, and 15 GHz, the nighttime values indicate sensitivity losses of 1, 10 and 20%, respectively. ATA's wide-bandwidth receiver permits observations over a continuous range 0.5-11.2 GHz. We probe the antenna optical gain and beam pattern stability as a function of focus position and observation frequency, concluding that ATA can produce high fidelity images over a decade of simultaneous observation frequencies. We quantify solar heating effects on antenna sensitivity and pointing accuracy. We find that during the day, observations >=5 GHz will suffer some sensitivity loss and it may be necessary to make antenna pointing corrections on a 1-2 hourly basis.

  9. Results from the Fly’s Eye Fast Radio Transient Search at the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Siemion, Andrew; Bower, G.; Dexter, M.; Foster, G.; Mallard, W.; McMahon, P.; Wagner, M.; Werthimer, D.; Allen Telescope Array Team

    2011-01-01

    The relatively unexplored fast radio transient parameter space is known to be home to a variety of interesting sources, including rotating radio transients (RRATs), γ-ray burst (GRB) afterglows and pulsar giant pulses. In addition, a variety of hypothesized but as yet unobserved phenomena, such as primordial black hole evap- oration (Rees, 1977), prompt emission associated with coalescing massive objects (Hansen & Lyutikov, 2008) and hyper-flares from magnetars (Popov & Postnov, 2007) have been suggested. The announcement by Lorimer et al. of the detection of a powerful ( 30 Jy) and highly dispersed (DM 375 pc cm-3) radio pulse in Parkes multi-beam survey data (Lorimer et al., 2007), and subsequent consternation, have demonstrated both the potential utility of bright radio pulses as probes of the ISM and IGM, as well as the need for wide-field surveys characterizing the fast radio transient population. We present results from the 450-hour Fly’s Eye survey for powerful dispersed radio pulses at the Allen Telescope Array (ATA). The Fly’s Eye spectrometer processes 44 independent signal paths, each with a bandwidth of 209 MHz centered at 1420 MHz, and produces 128-channel power spectra accumulated for 0.6ms. Independent antenna-pointings of the extant 42-dish ATA yields a maximum total field-of-view of approximately 198 square degrees.

  10. 1998 Mars Missions Science Briefing

    NASA Technical Reports Server (NTRS)

    1998-01-01

    NASA executives gathered together for an interview to discuss the 1998 Mars Mission. A simulated overview of the Lander Mission is presented. Also presented are views of pre-launch activities, countdown, and launch of the spacecraft, burnouts of the first, second, and third engines, and the probe separating from the spacecraft. During this mission the Lander performs in situ investigations that address the science theme "Volatiles and Climate History" on Mars. The purpose of this mission is to study the following: climate; life; water; carbon dioxide; and dust particles.

  11. Ray tracing simulations for the wide-field x-ray telescope of the Einstein Probe mission based on Geant4 and XRTG4

    NASA Astrophysics Data System (ADS)

    Zhao, Donghua; Zhang, Chen; Yuan, Weimin; Willingale, Richard; Ling, Zhixing; Feng, Hua; Li, Hong; Ji, Jianfeng; Wang, Wenxin; Zhang, Shuangnan

    2014-07-01

    Einstein Probe (EP) is a proposed small scientific satellite dedicated to time-domain astrophysics working in the soft X-ray band. It will discover transients and monitor variable objects in 0.5-4 keV, for which it will employ a very large instantaneous field-of-view (60° × 60°), along with moderate spatial resolution (FWHM ˜ 5 arcmin). Its wide-field imaging capability will be achieved by using established technology in novel lobster-eye optics. In this paper, we present Monte-Carlo simulations for the focusing capabilities of EP's Wide-field X-ray Telescope (WXT). The simulations are performed using Geant4 with an X-ray tracer which was developed by cosine (http://cosine.nl/) to trace X-rays. Our work is the first step toward building a comprehensive model with which the design of the X-ray optics and the ultimate sensitivity of the instrument can be optimized by simulating the X-ray tracing and radiation environment of the system, including the focal plane detector and the shielding at the same time.

  12. The Allen telescope array: Commensal and efficient SETI

    NASA Astrophysics Data System (ADS)

    Deboer, David R.

    2006-12-01

    The Allen telescope array (ATA) currently under construction affords the possibility of a dedicated and highly efficient SETI program that may be done commensally with other radio astronomy programs. This symbiosis is important in order to maintain and sustain the long-term effort that may be required in order to achieve success as a positive or null result. The technology that is being exploited is the construction of many small elements that allow large fields-of-view at high sensitivity, the use of ultra-wideband front-ends, and the use of flexible digital “intermediate frequency (IF)” systems. The project is under construction in phases, with the first 32 antennas expected to be functional in the fall of 2004, the next 173 dishes operational early 2006, with plans for 350 antennas total within this decade.

  13. Titan Probe navigation analysis

    NASA Technical Reports Server (NTRS)

    Vijayaraghavan, A.; Wood, L. J.

    1986-01-01

    In the proposed Cassini mission, a combined Saturn Orbiter/Titan Probe spacecraft will be launched from the Space Shuttle to arrive at Saturn around 2002, by means of a delta-VEGA trajectory. After Saturn-orbit insertion and a pericrone raise maneuver, the probe will be released to enter the Titan atmosphere and impact onto its surface. During its descent phase and impact onto Titan, the probe will maintain radio contact with the orbiter. Since the Titan-probe experimental phase lasts for only about four hours, probe-orbiter geometry and probe-delivery accuracy are critical to successful completion of this part of the mission. From a preliminary navigation analysis for probe delivery accuracy, it seems feasible to deliver the probe within 50 km (1-sigma value) of the desired aim-point in the Titan B-plane. The covariance study, however, clearly indicates the need for optical data, in addition to radio metric data. A Monte Carlo study indicates that a Delta-V capability of 98 m/sec for trajectory correction maneuvers will be sufficient to cover 99 percent of all contingencies during the segment from Saturn-orbit insertion to Titan-probe release.

  14. ESA Venus Entry Probe Study

    NASA Technical Reports Server (NTRS)

    vandenBerg, M. L.; Falkner, P.; Phipps, A.; Underwood, J. C.; Lingard, J. S.; Moorhouse, J.; Kraft, S.; Peacock, A.

    2005-01-01

    The Venus Entry Probe is one of ESA s Technology Reference Studies (TRS). The purpose of the Technology Reference Studies is to provide a focus for the development of strategically important technologies that are of likely relevance for future scientific missions. The aim of the Venus Entry Probe TRS is to study approaches for low cost in-situ exploration of Venus and other planetary bodies with a significant atmosphere. In this paper, the mission objectives and an outline of the mission concept of the Venus Entry Probe TRS are presented.

  15. Radiation Belt Storm Probes (RBSP) Education and Public Outreach Program

    NASA Astrophysics Data System (ADS)

    Turney, D.; Matiella Novak, A.; Beisser, K.; Fox, N.

    2013-11-01

    The Radiation Belt Storm Probes (RBSP) Education and Public Outreach (E/PO) program serves as a pipeline of activities to inspire and educate a broad audience about Heliophysics and the Sun-Earth system, specifically the Van Allen Radiation Belts. The program is comprised of a variety of formal, informal and public outreach activities that all align with the NASA Education Portfolio Strategic Framework outcomes. These include lesson plans and curriculum for use in the classroom, teacher workshops, internship opportunities, activities that target underserved populations, collaboration with science centers and NASA visitors' centers and partnerships with experts in the Heliophysics and education disciplines. This paper will detail the activities that make up the RBSP E/PO program, their intended audiences, and an explanation as to how they align with the NASA education outcomes. Additionally, discussions on why these activities are necessary as part of a NASA mission are included. Finally, examples of how the RBSP E/PO team has carried out some of these activities will be discussed throughout.

  16. [The mission].

    PubMed

    Ruiz Moreno, J; Blanch Mon, A

    2000-01-01

    After having made a historical review of the concept of mission statement, of evaluating its importance (See Part I), of describing the bases to create a mission statement from a strategic perspective and of analyzing the advantages of this concept, probably more important as a business policy (See Parts I and II), the authors proceed to analyze the mission statement in health organizations. Due to the fact that a mission statement is lacking in the majority of health organizations, the strategy of health organizations are not exactly favored; as a consequence, neither are its competitive advantage nor the development of its essential competencies. After presenting a series of mission statements corresponding to Anglo-Saxon health organizations, the authors highlight two mission statements corresponding to our social context. The article finishes by suggesting an adequate sequence for developing a mission statement in those health organizations having a strategic sense. PMID:10983153

  17. Advancements in empirical geomagnetic field modeling during the Van Allen Probes era

    NASA Astrophysics Data System (ADS)

    Stephens, G. K.; Sitnov, M. I.; Korth, H.; Ukhorskiy, A. Y.

    2014-12-01

    An empirical magnetic field model was developed with increased equatorial spatial resolution and fit to recent sources of inner-magnetospheric magnetometer data. The model describes the equatorial currents with a basis-function expansion approach, instead of custom-tailored current systems, allowing the equatorial currents to be inferred directly from data. This magnetometer data was binned using global storm parameters, allowing it to model the storm-time evolution of the magnetosphere during the March 2013 geomagnetic storm. It reconstructs the symmetric and asymmetric ring currents, including a westward ring current at R > 4 RE and a eastward ring current at R < 3 RE. The ring current is highly asymmetric during the main phase of the storm and returns to a symmetric ring current during the recovery phase. Other findings include a westward rotation and of the Region-2 ring current system during the main phase of the storm and a closed banana current in the inner-magenteosphere closing through asymmetries in the westward and eastward ring current system, both of which are consistent with first-principles kinetic models.

  18. 2nd International Planetary Probe Workshop

    NASA Technical Reports Server (NTRS)

    Venkatapathy, Ethiraj; Martinez, Ed; Arcadi, Marla

    2005-01-01

    Included are presentations from the 2nd International Planetary Probe Workshop. The purpose of the second workshop was to continue to unite the community of planetary scientists, spacecraft engineers and mission designers and planners; whose expertise, experience and interests are in the areas of entry probe trajectory and attitude determination, and the aerodynamics/aerothermodynamics of planetary entry vehicles. Mars lander missions and the first probe mission to Titan made 2004 an exciting year for planetary exploration. The Workshop addressed entry probe science, engineering challenges, mission design and instruments, along with the challenges of reconstruction of the entry, descent and landing or the aerocapture phases. Topics addressed included methods, technologies, and algorithms currently employed; techniques and results from the rich history of entry probe science such as PAET, Venera/Vega, Pioneer Venus, Viking, Galileo, Mars Pathfinder and Mars MER; upcoming missions such as the imminent entry of Huygens and future Mars entry probes; and new and novel instrumentation and methodologies.

  19. Study of alternative probe technologies

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A number of implied technologies for a deep probe mission was examined; i.e., one that would provide the capability to scientifically examine planetary atmospheres at the 1000 bar level. Conditions imposed by current Jupiter, Saturn, and Uranus atmospheric models were considered. The major thrust of the measurements was to determine lower atmosphere composition, even to trace constituents of one part per billion. Two types of instruments having the necessary accuracy to meet the science objectives were considered and integrated into a deep probe configuration. One deep probe option that resulted was identified as a Minimum Technology Development approach. The significant feature of this option is that only three technology developments are required to enable the mission, i.e., (1) science instrument development, (2) advanced data processing, and (3) external high pressure/thermal insulation. It is concluded that a probe designed for a Jupiter mission could, with minor changes, be used for a Saturn or Uranus mission.

  20. Synergy Between Entry Probes and Orbiters

    NASA Technical Reports Server (NTRS)

    Young, Richard E.

    2005-01-01

    We identify two catagories of probe-orbiter interactions which benefit the science return from a particular mission. The first category is termed "Mission Design Aspects". This category is meant to describe those aspects of the mission design involving the orbiter that affect the science return from the probe(s). The second category of probe-orbiter interaction is termed "Orbiter-Probe Science Interactions", and is meant to include interactions between oribter and probe(s) that directly involve science measurements made from each platform. Two mission related aspects of probe-orbiter interactions are delivery of a probe(s) to the entry site(s) by an orbiter, and communication between each probe and the orbiter. We consider four general probe-orbiter science interactions that greatly enhance, or in certain cases are essential for, the mission science return. The four topics are, global context of the probe entry site(s), ground truth for remote sensing observations of an orbiter, atmospheric composition measurements, and wind measurements.

  1. Branching Out: Rhodium-Catalyzed Allylation with Alkynes and Allenes.

    PubMed

    Koschker, Philipp; Breit, Bernhard

    2016-08-16

    We present a new and efficient strategy for the atom-economic transformation of both alkynes and allenes to allylic functionalized structures via a Rh-catalyzed isomerization/addition reaction which has been developed in our working group. Our methodology thus grants access to an important structural class valued in modern organic chemistry for both its versatility for further functionalization and the potential for asymmetric synthesis with the construction of a new stereogenic center. This new methodology, inspired by mechanistic investigations by Werner in the late 1980s and based on preliminary work by Yamamoto and Trost, offers an attractive alternative to other established methods for allylic functionalization such as allylic substitution or allylic oxidation. The main advantage of our methodology consists of the inherent atom economy in comparison to allylic oxidation or substitution, which both produce stoichiometric amounts of waste and, in case of the substitution reaction, require prefunctionalization of the starting material. Starting out with the discovery of a highly branched-selective coupling reaction of carboxylic acids with terminal alkynes using a Rh(I)/DPEphos complex as the catalyst system, over the past 5 years we were able to continuously expand upon this chemistry, introducing various (pro)nucleophiles for the selective C-O, C-S, C-N, and C-C functionalization of both alkynes and the double-bond isomeric allenes by choosing the appropriate rhodium/bidentate phosphine catalyst. Thus, valuable compounds such as branched allylic ethers, sulfones, amines, or γ,δ-unsaturated ketones were successfully synthesized in high yields and with a broad substrate scope. Beyond the branched selectivity inherent to rhodium, many of the presented methodologies display additional degrees of selectivity in regard to regio-, diastereo-, and enantioselective transformations, with one example even proceeding via a dynamic kinetic resolution. Many advances

  2. [Book review] Green engineering: environmentally conscious design, by David T. Allen and David R. Shonnard

    USGS Publications Warehouse

    Boustany, R.G.

    2002-01-01

    Review of: Green engineering: Environmentally conscious design / David T. Allen and David R. Shonnard / Prentice-Hall, Inc., One Lake Street, Upper Saddle River, NJ 07458. 2002. 552 pages. ISBN 0-13-061908-6.

  3. Solar Probe Plus

    NASA Technical Reports Server (NTRS)

    Szabo, Adam

    2011-01-01

    The NASA Solar Probe Plus mission is planned to be launched in 2018 to study the upper solar corona with both.in-situ and remote sensing instrumentation. The mission will utilize 6 Venus gravity assist maneuver to gradually lower its perihelion to 9.5 Rs below the expected Alfven pOint to study the sub-alfvenic solar wind that is still at least partially co-rotates with the Sun. The detailed science objectives of this mission will be discussed. SPP will have a strong synergy with The ESA/NASA Solar orbiter mission to be launched a year ahead. Both missions will focus on the inner heliosphere and will have complimentary instrumentations. Strategies to exploit this synergy will be also presented.

  4. Rhodium-Catalyzed Cross-Cyclotrimerization and Dimerization of Allenes with Alkynes.

    PubMed

    Sakashita, Kazuki; Shibata, Yu; Tanaka, Ken

    2016-06-01

    It has been established that a cationic rhodium(I)/binap complex catalyzes the cross-cyclotrimerization of two molecules of a monosubstituted allene with one molecule of a functionalized alkyne to give 3,6-dialkylidenecyclohex-1-enes. In contrast, the reactions involving di- or trisubstituted allenes and/or unfunctionalized alkynes afforded cross-dimerization products, substituted dendralenes, through β-hydrogen elimination from the corresponding rhodacycles. PMID:27110668

  5. Iron‐catalyzed Cross‐Coupling of Propargyl Carboxylates and Grignard Reagents: Synthesis of Substituted Allenes

    PubMed Central

    Kessler, Simon N.

    2016-01-01

    Abstract Presented herein is a mild, facile, and efficient iron‐catalyzed synthesis of substituted allenes from propargyl carboxylates and Grignard reagents. Only 1–5 mol % of the inexpensive and environmentally benign [Fe(acac)3] at −20 °C was sufficient to afford a broad range of substituted allenes in excellent yields. The method tolerates a variety of functional groups. PMID:26890161

  6. Diastereoselective Synthesis of the Aminocyclitol Core of Jogyamycin via an Allene Aziridination Strategy

    PubMed Central

    Gerstner, Nels C.; Adams, Christopher S.; Grigg, R. David; Tretbar, Maik; Rigoli, Jared W.; Schomaker, Jennifer M.

    2016-01-01

    Oxidative allene amination provides rapid access to densely functionalized amine-containing stereotriads through highly reactive bicyclic methyleneaziridine intermediates. This strategy has been demonstrated as a viable approach for the construction of the densely functionalized aminocyclitol core of jogyamycin, a natural product with potent antiprotozoal activity. Importantly, the flexibility of oxidative allene amination will enable the syntheses of modified aminocyclitol analogues of the jogyamycin core. PMID:26741730

  7. Microwave-promoted synthesis of bicyclic azocine-β-lactams from bis(allenes).

    PubMed

    Alcaide, Benito; Almendros, Pedro; Aragoncillo, Cristina; Fernández, Israel; Gómez-Campillos, Gonzalo

    2014-08-01

    A metal-free preparation of structurally novel bicyclic azocine-β-lactams has been developed. The first examples accounting for the preparation of eight-membered rings from bis(allenes) in the absence of metals have been achieved by the thermolysis of nonconjugated 2-azetidinone-tethered bis(allenes) on application of microwave irradiation. This selective carbocyclization reaction has been studied experimentally, and additionally, its mechanism has been investigated by a DFT study. PMID:25010752

  8. IMP mission

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The program requirements and operations requirements for the IMP mission are presented. The satellite configuration is described and the missions are analyzed. The support equipment, logistics, range facilities, and responsibilities of the launching organizations are defined. The systems for telemetry, communications, satellite tracking, and satellite control are identified.

  9. (Hetero)aromatics from dienynes, enediynes and enyne-allenes.

    PubMed

    Raviola, Carlotta; Protti, Stefano; Ravelli, Davide; Fagnoni, Maurizio

    2016-08-01

    The construction of aromatic rings has become a key objective for organic chemists. While several strategies have been developed for the functionalization of pre-formed aromatic rings, the direct construction of an aromatic core starting from polyunsaturated systems is yet a less explored field. The potential of such reactions in the formation of aromatics increased at a regular pace in the last few years. Nowadays, there are reliable and well-established procedures to prepare polyenic derivatives, such as dienynes, enediynes, enyne-allenes and hetero-analogues. This has stimulated their use in the development of innovative cycloaromatizations. Different examples have recently emerged, suggesting large potential of this strategy in the preparation of (hetero)aromatics. Accordingly, this review highlights the recent advancements in this field and describes the different conditions exploited to trigger the process, including thermal and photochemical activation, as well as the use of transition metal catalysis and the addition of electrophiles/nucleophiles or radical species. PMID:27263976

  10. The Allen Telescope Array Search for Electrostatic Discharges on Mars

    NASA Astrophysics Data System (ADS)

    Anderson, Marin M.; Siemion, Andrew P. V.; Barott, William C.; Bower, Geoffrey C.; Delory, Gregory T.; de Pater, Imke; Werthimer, Dan

    2012-01-01

    The Allen Telescope Array was used to monitor Mars between 2010 March 9 and June 2, over a total of approximately 30 hr, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. of the detection of non-thermal microwave radiation from Mars characterized by peaks in the power spectrum of the kurtosis, or kurtstrum, at 10 Hz, coinciding with a large dust storm event on 2006 June 8. For these observations, we developed a wideband signal processor at the Center for Astronomy Signal Processing and Electronics Research. This 1024 channel spectrometer calculates the accumulated power and power-squared, from which the spectral kurtosis is calculated post-observation. Variations in the kurtosis are indicative of non-Gaussianity in the signal, which can be used to detect variable cosmic signals as well as radio frequency interference (RFI). During the three-month period of observations, dust activity occurred on Mars in the form of small-scale dust storms; however, no signals indicating lightning discharge were detected. Frequent signals in the kurtstrum that contain spectral peaks with an approximate 10 Hz fundamental were seen at both 3.2 and 8.0 GHz, but were the result of narrowband RFI with harmonics spread over a broad frequency range.

  11. THE ALLEN TELESCOPE ARRAY SEARCH FOR ELECTROSTATIC DISCHARGES ON MARS

    SciTech Connect

    Anderson, Marin M.; Siemion, Andrew P. V.; Bower, Geoffrey C.; De Pater, Imke; Barott, William C.; Delory, Gregory T.; Werthimer, Dan

    2012-01-01

    The Allen Telescope Array was used to monitor Mars between 2010 March 9 and June 2, over a total of approximately 30 hr, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. of the detection of non-thermal microwave radiation from Mars characterized by peaks in the power spectrum of the kurtosis, or kurtstrum, at 10 Hz, coinciding with a large dust storm event on 2006 June 8. For these observations, we developed a wideband signal processor at the Center for Astronomy Signal Processing and Electronics Research. This 1024 channel spectrometer calculates the accumulated power and power-squared, from which the spectral kurtosis is calculated post-observation. Variations in the kurtosis are indicative of non-Gaussianity in the signal, which can be used to detect variable cosmic signals as well as radio frequency interference (RFI). During the three-month period of observations, dust activity occurred on Mars in the form of small-scale dust storms; however, no signals indicating lightning discharge were detected. Frequent signals in the kurtstrum that contain spectral peaks with an approximate 10 Hz fundamental were seen at both 3.2 and 8.0 GHz, but were the result of narrowband RFI with harmonics spread over a broad frequency range.

  12. The Allen Telescope Array as Square Kilometer Array Pathfinder

    NASA Astrophysics Data System (ADS)

    Bower, Geoffrey C.

    2007-12-01

    The Allen Telescope Array (ATA) is a new radio interferometer that has begun scientific operations in 2007. Many of the technologies, techniques, and observing modes developed for the ATA are directly applicable to the Square Kilometer Array (SKA). The ATA is a pioneer of the LNSD, which refers to a large number (LN) of small diameter (SD) dishes to create the array. This concept underlies nearly all SKA designs. Other relevant technologies are the offset Gregorian ATA antenna, the ATA wideband log periodic feed, transport of broadband data over fiber optic cables, and flexible digital signal processing electronics. The small dishes of the ATA gives it extraordinary wide-field imaging and survey capability but also require new solutions for calibration and imaging. Real time imaging, rapid response to transients, and thinking telescope technology are also under development. Finally, the ATA is developing commensal observing modes, which enable multiple simultaneous science programs, such as SETI, transient surveys, and HI surveys. Opportunities exist for community members to perform scientific investigations as well as develop techniques and technology for the SKA through use of the ATA.

  13. Active and passive microwave measurements in Hurricane Allen

    NASA Technical Reports Server (NTRS)

    Delnore, V. E.; Bahn, G. S.; Grantham, W. L.; Harrington, R. F.; Jones, W. L.

    1985-01-01

    The NASA Langley Research Center analysis of the airborne microwave remote sensing measurements of Hurricane Allen obtained on August 5 and 8, 1980 is summarized. The instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm sea value. The rain rate is obtained from the difference between antenna temperature increases measured at two frequencies, and wind vector is determined from the sea surface normalized radar cross section measured at several azimuths. Comparison wind data were provided from the inertial navigation systems aboard both the C-130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. Evaluation of the surface winds obtained with the two microwave instruments was limited to comparisons with each other and with the flight level winds. Two important conclusions are drawn from these comparisons: (1) the radiometer is accurate when predicting flight level wind speeds and rain; and (2) the scatterometer produces well behaved and consistent wind vectors for the rain free periods.

  14. Outer planet entry probe system study. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    General mission considerations and science prospectus, which are of a general nature that applies to several or all planetary applications, are presented. Five probe systems are defined: nominal Jupiter probe system, and Jupiter probe-dedicated alternative probe system, Jupiter spacecraft radiation-compatible alternative probe system, Saturn probe system, and Saturn probe applicability for Uranus. Parametric analysis is summarized for mission analysis of a general nature, and then for specific missions to Jupiter, Saturn, Uranus, and Neptune. The program is also discussed from the hardware availability viewpoint and the aspect of commonality.

  15. Innermost Van Allen Radiation Belt for High Energy Protons at Saturn

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2008-01-01

    The high energy proton radiation belts of Saturn are energetically dominated by the source from cosmic ray albedo neutron decay (CRAND), trapping of protons from beta decay of neutrons emitted from galactic cosmic ray nuclear interactions with the main rings. These belts were originally discovered in wide gaps between the A-ring, Janus/Epimetheus, Mimas, and Enceladus. The narrow F and G rings significant affected the CRAND protons but did not produce total depletion. Voyager 2 measurements subsequently revealed an outermost CRAND proton belt beyond Enceladus. Although the source rate is small, the trapping times limited by radial magnetospheric diffusion are very long, about ten years at peak measured flux inwards of the G ring, so large fluxes can accumulate unless otherwise limited in the trapping region by neutral gas, dust, and ring body interactions. One proposed final extension of the Cassini Orbiter mission would place perikrone in a 3000-km gap between the inner D ring and the upper atmosphere of Saturn. Experience with CRAND in the Earth's inner Van Allen proton belt suggests that a similar innermost belt might be found in this comparably wide region at Saturn. Radial dependence of magnetospheric diffusion, proximity to the ring neutron source, and northward magnetic offset of Saturn's magnetic equator from the ring plane could potentially produce peak fluxes several orders of magnitude higher than previously measured outside the main rings. Even brief passes through such an intense environment of highly penetrating protons would be a significant concern for spacecraft operations and science observations. Actual fluxes are limited by losses in Saturn's exospheric gas and in a dust environment likely comparable to that of the known CRAND proton belts. The first numerical model of this unexplored radiation belt is presented to determine limits on peak magnitude and radial profile of the proton flux distribution.

  16. The Euclid Mission

    NASA Astrophysics Data System (ADS)

    Racca, Giuseppe; Laureijs, Rene

    Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) designed to investigate the nature of dark energy, dark matter and gravity by observing their signatures on the geometry of the Universe and on the formation of large structures over cosmological timescales. Euclid is optimised for two primary cosmological probes: Weak gravitational Lensing, which requires the measurement of the shape and photometric redshifts of distant galaxies, and Galaxy Clustering, based on the measurement of the 3-dimensional distribution of galaxies through their spectroscopic redshifts. The mission is scheduled for a launch date in the first half of 2020 and is designed for 6 years of nominal survey operations. The Euclid Spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems, the instruments warm electronics units, the sun shield and the solar arrays. The Payload Module consists of a 1.2 m three-mirror Korsch type telescope and of two instruments, the visible imager and the near-infrared spectro-photometer, both covering a large common field-of-view enabling to survey more than 35% of the entire sky. The ground segment is broken down into three elements: the Mission Operations, the Science Operations under the responsibility of ESA and the Science Data Centres belonging to the Euclid Consortium. We will describe the overall mission, the mission elements architecture and the current project status.

  17. Geospace Magnetospheric Dynamics Mission

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Kluever, C.; Burch, J. L.; Fennell, J. F.; Hack, K.; Hillard, G. B.; Kurth, W. S.; Lopez, R. E.; Luhmann, J. G.; Martin, J. B.; Hanson, J. E.

    1998-01-01

    The Geospace Magnetospheric Dynamics (GMD) mission is designed to provide very closely spaced, multipoint measurements in the thin current sheets of the magnetosphere to determine the relation between small scale processes and the global dynamics of the magnetosphere. Its trajectory is specifically designed to optimize the time spent in the current layers and to minimize radiation damage to the spacecraft. Observations are concentrated in the region 8 to 40 R(sub E) The mission consists of three phases. After a launch into geostationary transfer orbit the orbits are circularized to probe the region between geostationary orbit and the magnetopause; next the orbit is elongated keeping perigee at the magnetopause while keeping the line of apsides down the tail. Finally, once apogee reaches 40 R(sub E) the inclination is changed so that the orbit will match the profile of the noon-midnight meridian of the magnetosphere. This mission consists of 4 solar electrically propelled vehicles, each with a single NSTAR thruster utilizing 100 kg of Xe to tour the magnetosphere in the course of a 4.4 year mission, the same thrusters that have been successfully tested on the Deep Space-1 mission.

  18. The Phoenix Pluto Probe

    NASA Technical Reports Server (NTRS)

    Gunning, George R.; Spapperi, Jeff; Wilkinson, Jeffrey P.; Eldred, Jim; Labij, Dennis; Strinni, Meredith

    1990-01-01

    A design proposal for an unmanned probe to Pluto is presented. The topics covered include: (1) scientific instrumentation; (2) mission management, planning, and costing; (3) power and propulsion system; (4) structural subsystem; (5) command, control, and communication; and (6) attitude and articulation control.

  19. Probing the Solar System

    ERIC Educational Resources Information Center

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  20. THE ALLEN TELESCOPE ARRAY FLY'S EYE SURVEY FOR FAST RADIO TRANSIENTS

    SciTech Connect

    Siemion, Andrew P.V.; Bower, Geoffrey C.; Wagner, Mark I.; Werthimer, Dan; Backer, Don; Foster, Griffin; McMahon, Peter L.; Cordes, Jim; Van Leeuwen, Joeri

    2012-01-10

    The relatively unexplored fast radio transient parameter space is known to be home to a variety of interesting sources, including pulsars, pulsar giant pulses, and non-thermal emission from planetary magnetospheres. In addition, a variety of hypothesized but as-yet-unobserved phenomena such as primordial black hole evaporation and prompt emission associated with coalescing massive objects have been suggested. The 2007 announcement by Lorimer et al. of the detection of a bright (30 Jy) radio pulse that was inferred to be of extragalactic origin and the subsequent consternation have demonstrated both the need for wide-field surveys characterizing the fast-transient parameter space and the potential utility of bright radio pulses as probes of the interstellar medium and intergalactic medium. Here we present results from the 450 hr, 150 deg{sup 2} Fly's Eye survey for bright dispersed radio pulses at the Allen Telescope Array (ATA). The Fly's Eye Spectrometer produces 128 channel power spectra over a 209 MHz bandwidth, centered at 1430 MHz, on 44 independent signal paths originating with 30 independent ATA antennae. Data were dedispersed between 0 and 2000 pc cm{sup -3} and searched for pulses with dispersion measures greater than 50 pc cm{sup -3} between 625 {mu}s and 5 s in duration. No pulses were detected in the survey, implying a limiting rate of less than 2 sky{sup -1} hr{sup -1} for 10 ms duration pulses having apparent energy densities greater than 440 kJy {mu}s, or mean flux densities greater than 44 Jy. Here we present details of the instrument, experiment, and observations, including a discussion of our results in light of other single pulse searches.

  1. Synergy Between probes and Orbiter

    NASA Technical Reports Server (NTRS)

    Young, Richard E.

    2005-01-01

    There are many ways in which the science return from a planetary mission is considerably enhanced by interactions between entry probes and a mission orbiter. Mission configuration aspects that are desirable include delivery of entry probes by the orbiter, and communication between probe and orbiter. Both of these mission aspects could greatly enhance access to key scientific sites that might not otherwise be accessible using delivery from say, a flyby, or employing direct communication from probes to Earth. Examples for Venus and Jupiter will be discussed. A second class of orbiter-probe interaction could better be termed direct probe-orbiter science collaboration. That would include, determining the global context of the entry probe sites from the orbiter, obtaining ground truth from the probe for remote sensing observations from the orbiter, observing the global and vertical distribution of key atmospheric trace species, and measuring the global and vertical distribution of clouds and winds. The importance of each of these items will be illustrated by particular examples.

  2. Assimilation and implications of AE-9/AP-9 in the design process of JPL missions

    NASA Astrophysics Data System (ADS)

    de Soria-Santacruz Pich, M.; Jun, I.

    2015-12-01

    The NASA AE-8/AP-8 has been the standard geospace environment specification for decades. This model describes the energetic particle environment around the Earth and is currently the default model used in the design of space missions at the Jet Propulsion Laboratory (JPL). Moreover, the model plays a critical role in the determination of the shielding and survivability of the satellites orbiting our planet. A recent update supported by the Air Force Research Laboratory (AFRL) and the National Reconnaissance Office (NRO), the AE-9/AP-9 model, was released in September 2012 and included many improvements like increased spatial resolution and the specification of the uncertainty due to instrument errors or space weather variability. A current effort at JPL is in place with the objective of making a decision within the Laboratory on the transition from AE-8/AP-8 to the new AE-9/AP-9. In this study we present the results of this effort, which involves the comparison between both versions of the model for different satellite orbits, the comparison between AE-9/AP-9 and in-situ satellite data from the Van Allen Probes and the OSTM/Jason 2 satellite, and the implications of adopting the new model for spacecraft design in terms of survivability, shielding, single event effects, and spacecraft charging.

  3. Mission scheduling

    NASA Technical Reports Server (NTRS)

    Gaspin, Christine

    1989-01-01

    How a neural network can work, compared to a hybrid system based on an operations research and artificial intelligence approach, is investigated through a mission scheduling problem. The characteristic features of each system are discussed.

  4. Probe assembly

    SciTech Connect

    Avera, C.J.

    1981-01-06

    A hand-held probe assembly, suitable for monitoring a radioactive fibrinogen tracer, is disclosed comprising a substantially cylindrically shaped probe handle having an open end. The probe handle is adapted to be interconnected with electrical circuitry for monitoring radioactivity that is sensed or detected by the probe assembly. Mounted within the probe handle is a probe body assembly that includes a cylindrically shaped probe body inserted through the open end of the probe handle. The probe body includes a photomultiplier tube that is electrically connected with a male connector positioned at the rearward end of the probe body. Mounted at the opposite end of the probe body is a probe head which supports an optical coupler therewithin. The probe head is interconnected with a probe cap which supports a detecting crystal. The probe body assembly, which consists of the probe body, the probe head, and the probe cap is supported within the probe handle by means of a pair of compressible o-rings which permit the probe assembly to be freely rotatable, preferably through 360*, within the probe handle and removable therefrom without requiring any disassembly.

  5. James A. Van Allen: The Trip to Jupiter

    ERIC Educational Resources Information Center

    Jacobsen, Sally

    1973-01-01

    Discusses the research purposes and activities of the Pioneer mission, including the instruments used, data on Jupiter's radiation belt, and information about cosmic ray intensity. Included is a description of the scientist's view about the value of the space program. (CC)

  6. The Swift GRB Mission

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Chincarini, Guido

    2004-01-01

    Swift is a MIDEX mission that is in development for launch in October 2004. It is a multiwavelength transient observatory for GRB astronomy. The goals of the mission are to determine the origin of GRBs and their afterglows and use bursts to probe the early Universe. A wide-field gamma-ray camera will detect mare than 100 GRBs per year to -3 times fainter than BATSE. Sensitive narrow-field X-ray and UV/optical telescopes will be pointed at the burst location in 20 to 75 sec by an autonomously controlled spacecraft. Far each burst, aresec positions will be determined and optical/UV/X-ray/gamma-say spectrophotometry performed. Measurements of redshift will be made for many burstes. The instrumentation is a combination of superb existing flight-spare hardware and design from XMM and Spectrum-X/JET-X contributed by collaborators in the UK and Italy and development of a coded-aperture camera with a large-area (approx. 0.5 square meter) CdZnTe detector array. Key components of the mission are vigorous follow-up and outreach programs to engage the astronomical community and public in Swift. The talk vi11 describe the mission statue and give a summary of plans for GRB operations. It is likely that Swift will have just been launched at the time of the conference.

  7. 1958 NASA/USAF Space Probes (ABLE-1). Volume 3; Vehicles, Trajectories, and Flight Histories

    NASA Technical Reports Server (NTRS)

    1959-01-01

    The three NASA/USAF lunar probes of August 17, October 13, and November 8, 1958 are described. Details of the program, the vehicles, the payloads, the firings, the tracking, and the results are presented. Principal result was the first experimental verification of a confined radiation zone of the type postulated by Van Allen and others.

  8. 1958 NASA/USAF Space Probes (ABLE-1). Volume 2; Payload and Experiments

    NASA Technical Reports Server (NTRS)

    1959-01-01

    The three NASA/USAF lunar probes of August 17, October 13, and November 8, 1958 are described. Details of the program, the vehicles, the payloads, the firings, the tracking, and the results are presented. Principal result was the first experimental verification of a confined radiation zone of the type postulated by Van Allen and others.

  9. Missions to Mercury

    NASA Astrophysics Data System (ADS)

    Grard, Réjean; Laakso, Harry; Svedhem, Håkan

    2002-10-01

    Mercury is a poorly known planet. It is difficult to observe from Earth and to explore with spacecraft, due to its proximity to the Sun. Only the NASA probe Mariner 10 caught a few glimpses of Mercury during three flybys, more than 27 years ago. Still, this planet is an interesting and important object because it belongs, like our own Earth, to the family of the terrestrial planets. After reviewing what we know about Mercury and recapitulating the major findings of Mariner 10, we present the two missions, Messenger and BepiColombo, which will perform the first systematic exploration of this forgotten planet in 2009 and 2014, respectively.

  10. Mission Possible

    ERIC Educational Resources Information Center

    Kittle, Penny, Ed.

    2009-01-01

    As teachers, our most important mission is to turn our students into readers. It sounds so simple, but it's hard work, and we're all on a deadline. Kittle describes a class in which her own expectations that students would become readers combined with a few impassioned strategies succeeded ... at least with a young man named Alan.

  11. Public health assessment for petitioned public health assessment, Allen Park Clay Mine, Allen Park, Wayne County, Michigan, Region 5. Cerclis No. MID980568711. Final report

    SciTech Connect

    Not Available

    1994-03-16

    The Allen Park Clay Mine (APCM) landfill is in Wayne County, Michigan, within the city limits of Allen Park. The Ford Motor Company developed a clay mine on the site before 1956. Since 1956, the clay excavations have been backfilled with wastes from the Ford Motor Company Rouge River Plant. Some of the wastes (i.e., electric arc furnace dust and decanter tank tar sludge) are classified by the U.S. Environmental Protection Agency as hazardous. Contaminants, including metals and polycyclic aromatic hydrocarbons (PAHs), have been identified in on-site groundwater, storm water runoff, and sediments. ATSDR could not determine if these contaminants were released from the APCM site. Metals have also been found in on-site air. No completed exposure pathways (ways for contaminants to reach the public) have been identified; however, potential exposure pathways do exist.

  12. Experiments in no-impact control of dingoes: comment on Allen et al. 2013

    PubMed Central

    2014-01-01

    There has been much recent debate in Australia over whether lethal control of dingoes incurs environmental costs, particularly by allowing increase of populations of mesopredators such as red foxes and feral cats. Allen et al. (2013) claim to show in their recent study that suppression of dingo activity by poison baiting does not lead to mesopredator release, because mesopredators are also suppressed by poisoning. We show that this claim is not supported by the data and analysis reported in Allen et al.’s paper. PMID:24558973

  13. Experiments in no-impact control of dingoes: comment on Allen et al. 2013.

    PubMed

    Johnson, Christopher N; Crowther, Mathew S; Dickman, Chris R; Letnic, Michael I; Newsome, Thomas M; Nimmo, Dale G; Ritchie, Euan G; Wallach, Arian D

    2014-01-01

    There has been much recent debate in Australia over whether lethal control of dingoes incurs environmental costs, particularly by allowing increase of populations of mesopredators such as red foxes and feral cats. Allen et al. (2013) claim to show in their recent study that suppression of dingo activity by poison baiting does not lead to mesopredator release, because mesopredators are also suppressed by poisoning. We show that this claim is not supported by the data and analysis reported in Allen et al.'s paper. PMID:24558973

  14. Copper-catalyzed regiodivergent silacarboxylation of allenes with carbon dioxide and a silylborane.

    PubMed

    Tani, Yosuke; Fujihara, Tetsuaki; Terao, Jun; Tsuji, Yasushi

    2014-12-24

    A regiodivergent silacarboxylation of allenes under a CO2 atmosphere with PhMe2Si-B(pin) as a silicon source in the presence of a copper catalyst at 70 °C has been developed. The regioselectivity of the reaction is successfully reversed by the proper choice of ligand; carboxylated vinylsilanes are obtained with rac-Me-DuPhos as the ligand, whereas the use of PCy3 affords carboxylated allylsilanes. Thus, two different carboxylated silanes can be selectively and regiodivergently synthesized from a single allene substrate. PMID:25469703

  15. Cascade Copper-Catalyzed 1,2,3-Trifunctionalization of Terminal Allenes.

    PubMed

    Zhao, Wanxiang; Montgomery, John

    2016-08-10

    A cascade cyanation/diborylation of terminal allenes proceeds efficiently with copper catalysis using bis(pinacolato)diboron (B2Pin2) and N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) as reagents. Mechanistic studies suggest that the process proceeds through cyanoborylation of the substituted π-system of the allene followed by hydroboration of the remaining π-component. A wide array of product derivatives may be accessed through site-selective cross-couplings and N-bromosuccinimide-promoted heteroarylations as well as standard oxidative and reductive conversions of the initially obtained adducts. PMID:27438071

  16. Regiodivergent Intermolecular [3+2] Cycloadditions of Vinyl Aziridines and Allenes: Stereospecific Synthesis of Chiral Pyrrolidines.

    PubMed

    Lin, Tao-Yan; Zhu, Chao-Ze; Zhang, Peichao; Wang, Yidong; Wu, Hai-Hong; Feng, Jian-Jun; Zhang, Junliang

    2016-08-26

    The first rhodium-catalyzed intermolecular [3+2] cycloaddition reaction of vinyl aziridines and allenes for the synthesis of enantioenriched functionalized pyrrolidines was realized. [3+2] cycloaddition with the proximal C=C bond of N-allenamides gave 3-methylene-pyrrolidines in high regio- and diastereoselectivity, whereas, 2-methylene-pyrrolidines were obtained as the major products by the cycloadditions of vinyl aziridines with the distal C=C bond of allenes. Use of readily available starting materials, a broad substrate scope, high selectivity, mild reaction conditions, as well as versatile functionalization of the cycloadducts make this approach very practical and attractive. PMID:27485044

  17. Replacement of two amino acids of 9R-dioxygenase-allene oxide synthase of Aspergillus niger inverts the chirality of the hydroperoxide and the allene oxide.

    PubMed

    Sooman, Linda; Wennman, Anneli; Hamberg, Mats; Hoffmann, Inga; Oliw, Ernst H

    2016-02-01

    The genome of Aspergillus niger codes for a fusion protein (EHA25900), which can be aligned with ~50% sequence identity to 9S-dioxygenase (DOX)-allene oxide synthase (AOS) of Fusarium oxysporum, homologues of the Fusarium and Colletotrichum complexes and with over 62% sequence identity to homologues of Aspergilli, including (DOX)-9R-AOS of Aspergillus terreus. The aims were to characterize the enzymatic activities of EHA25900 and to identify crucial amino acids for the stereospecificity. Recombinant EHA25900 oxidized 18:2n-6 sequentially to 9R-hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HPODE) and to a 9R(10)-allene oxide. 9S- and 9R-DOX-AOS catalyze abstraction of the pro-R hydrogen at C-11, but the direction of oxygen insertion differs. A comparison between twelve 9-DOX domains of 9S- and 9R-DOX-AOS revealed conserved amino acid differences, which could contribute to the chirality of products. The Gly616Ile replacement of 9R-DOX-AOS (A. niger) increased the biosynthesis of 9S-HPODE and the 9S(10)-allene oxide, whereas the Phe627Leu replacement led to biosynthesis of 9S-HPODE and the 9S(10)-allene oxide as main products. The double mutant (Gly616Ile, Phe627Leu) formed over 90% of the 9S stereoisomer of HPODE. 9S-HPODE was formed by antarafacial hydrogen abstraction and oxygen insertion, i.e., the original H-abstraction was retained but the product chirality was altered. We conclude that 9R-DOX-AOS can be altered to 9S-DOX-AOS by replacement of two amino acids (Gly616Ile, Phe627Leu) in the DOX domain. PMID:26603902

  18. Enzymatic kinetic resolution of primary allenic alcohols. Application to the total synthesis and stereochemical assignment of striatisporolide A.

    PubMed

    Deska, Jan; Bäckvall, Jan-E

    2009-09-01

    Crude Porcine pancreatic lipase was successfully used for the kinetic resolution of axially chiral primary allenic alcohols providing very high enantioselectivities with E values above 200. This simple access to optically active allenes was applied to the total synthesis of the fungal metabolite (-)-striatisporolide A, allowing its unambiguous stereochemical assignment. PMID:19675888

  19. A Critique of Mark D. Allen's "The Preservation of Verb Subcategory Knowledge in a Spoken Language Comprehension Deficit"

    ERIC Educational Resources Information Center

    Kemmerer, David

    2008-01-01

    Allen [Allen, M. (2005). "The preservation of verb subcategory knowledge in a spoken language comprehension deficit." "Brain and Language, 95", 255-264.] reports a single patient, WBN, who, during spoken language comprehension, is still able to access some of the syntactic properties of verbs despite being unable to access some of their semantic…

  20. Orion GN and C Mitigation Efforts for Van Allen Radiation

    NASA Technical Reports Server (NTRS)

    King, Ellis T.; Jackson, Mark

    2013-01-01

    The Orion Crew Module (CM) is NASA's next generation manned space vehicle, scheduled to return humans to lunar orbit in the coming decade. The Orion avionics and GN&C architectures have progressed through a number of project phases and are nearing completion of a major milestone. The first unmanned test mission, dubbed "Exploration Flight Test One" (EFT-1) is scheduled to launch from NASA Kennedy Space Center late next year and provides the first integrated test of all the vehicle systems, avionics and software.

  1. Proceedings: Outer Planet Probe Technology Workshop, summary volume

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A summary report and overview of the Outer Planet Probe Technology Conference are given. Summary data cover: (1) state of the art concerning mission definitions, probe requirements, systems, subsystems, and mission peculiar hardware, (2) mission and equipment trade-offs associated with Saturn/Uranus baseline configuration and the influence of Titan and Jupiter options on mission performance and costs, and (3) identification of critically required future R and D activities.

  2. Dual-spin attitude control for outer planet missions

    NASA Technical Reports Server (NTRS)

    Ward, R. S.; Tauke, G. J.

    1977-01-01

    The applicability of dual-spin technology to a Jupiter orbiter with probe mission was investigated. Basic mission and system level attitude control requirements were established and preliminary mechanization and control concepts developed. A comprehensive 18-degree-of-freedom digital simulation was utilized extensively to establish control laws, study dynamic interactions, and determined key sensitivities. Fundamental system/subsystem constraints were identified, and the applicability of dual-spin technology to a Jupiter orbiter with probe mission was validated.

  3. Titan and Enceladus mission (TANDEM)

    NASA Astrophysics Data System (ADS)

    Coustenis, A.

    2007-08-01

    Our understanding of Titan's atmosphere and surface has recently been enhanced by the data returned by the Cassini-Huygens mission. The Cassini orbiter will continue to be operational for about 3 more years during its extended mission. After this mission, any unanswered questions will forever remain unknown, unless we go back with an optimized orbital tour and advanced instrumentation. Considering the complementary nature of the geological, chemical and evolutionary history of Titan and Enceladus, we propose to carry out studies for a mission to perform an in situ exploration of these two objects in tandem. In our proposal we determine key science measurements, the types of samples that would be needed and the instrument suites for achieving the science goals. In particular, we develop conceptual designs for delivering the science payload, including orbiters, aerial platforms and probes, and define a launch/delivery/communication management architecture. This mission will require new technologies and capabilities so that the science goals can be achieved within the cost cap and acceptable risks. International participation will play a key role in achieving all the science goals of this mission. We will build this mission concept around a central core of single orbiter, a single Titan aerial probe and a core group of category 1 instruments. Aerobraking with Titan's atmosphere will be given serious consideration to minimize resource requirements and risk. This approach will allow a single orbiter to be used for both Enceladus science and Titan science with final orbit around Titan and later release of aerial probe(s) into Titan's atmosphere. The Titan aerial probe may be a Montgolfière balloon concept that will use the waster heat ~ 1000 watts from a single RTG power system. There will be a release of penetrator(s) on Enceladus also. This proposal addresses directly several of the scientific questions highlighted in the ESA Cosmic Vision 2015-2025 call, particularly

  4. Space Probe Launch

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Managed by Marshall Space Flight Center, the Space Tug was a reusable multipurpose space vehicle designed to transport payloads to different orbital inclinations. Utilizing mission-specific combinations of its three primary modules (crew, propulsion, and cargo) and a variety of supplementary kits, the Space Tug was capable of numerous space applications. This 1970 artist's concept depicts the Tug's propulsion module launching a space probe into lunar orbit.

  5. Galileo probe relay receiver

    NASA Technical Reports Server (NTRS)

    Prouty, D. A.; Von Der Embse, U. A.

    1982-01-01

    For the Jovian mission, the data link from the Galileo probe to the orbiter uses suppressed-carrier Manchester encoded BPSK modulation and is protected with R = 1/2, K = 7 convolutional coding. The receiver closes the link by acquiring, tracking, and demodulating the data. It has to operate in a highly stressed environment with severe frequency offset, frequency rate, wind gust, and antenna spin conditions. Salient features are described and breadboard test data presented.

  6. Titan probe technology assessment and technology development plan study

    NASA Technical Reports Server (NTRS)

    Castro, A. J.

    1980-01-01

    The need for technology advances to accomplish the Titan probe mission was determined by defining mission conditions and requirements and evaluating the technology impact on the baseline probe configuration. Mission characteristics found to be technology drivers include (1) ten years dormant life in space vacuum; (2) unknown surface conditions, various sample materials, and a surface temperature; and (3) mission constraints of the Saturn Orbiter Dual Probe mission regarding weight allocation. The following areas were identified for further development: surface sample acquisition system; battery powered system; nonmetallic materials; magnetic bubble memory devices, and the landing system. Preentry science, reliability, and weight reduction and redundancy must also be considered.

  7. Science Planning for the TROPIX Mission

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1998-01-01

    The objective of the study grant was to undertake the planning needed to execute meaningful solar electric propulsion missions in the magnetosphere and beyond. The first mission examined was the Transfer Orbit Plasma Investigation Experiment (TROPIX) mission to spiral outward through the magnetosphere. The next mission examined was to the moon and an asteroid. Entitled Diana, it was proposed to NASA in October 1994. Two similar missions were conceived in 1996 entitled CNR for Comet Nucleus Rendezvous and MBAR for Main Belt Asteroid Rendezvous. The latter mission was again proposed in 1998. All four of these missions were unsuccessfully proposed to the NASA Discovery program. Nevertheless we were partially successful in that the Deep Space 1 (DS1) mission was eventually carried out nearly duplicating our CNR mission. Returning to the magnetosphere we studied and proposed to the Medium Class Explorer (MIDEX) program a MidEx mission called TEMPEST, in 1995. This mission included two solar electric spacecraft that spiraled outward in the magnetosphere: one at near 900 inclination and one in the equatorial plane. This mission was not selected for flight. Next we proposed a single SEP vehicle to carry Energetic Neutral Atom (ENA) imagers and inside observations to complement the IMAGE mission providing needed data to properly interpret the IMAGE data. This mission called SESAME was submitted unsuccessfully in 1997. One proposal was successful. A study grant was awarded to examine a four spacecraft solar electric mission, named Global Magnetospheric Dynamics. This study was completed and a report on this mission is attached but events overtook this design and a separate study team was selected to design a classical chemical mission as a Solar Terrestrial Probe. Competing proposals such as through the MIDEX opportunity were expressly forbidden. A bibliography is attached.

  8. Atmospheric entry probes for outer planet exploration. Outer planet entry probe technical summary

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The use of unmanned space probes for investigating the conditions existing on and around the outer planets of the solar system is discussed. The subjects included in the report are: (1) the design of a common entry probe for outer planet missions, (2) the significant trades related to the development of a common probe design, (3) the impact of bus selection on probe design, (4) the impact of probe requirements on bus modifications, and (5) the key technology elements recommended for advanced development. Drawings and illustrations of typical probes are included to show the components and systems used in the space probes.

  9. 76 FR 9636 - Franklin Financial Corporation, Inc., Glen Allen, VA; Approval of Conversion Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ... Office of Thrift Supervision Franklin Financial Corporation, Inc., Glen Allen, VA; Approval of Conversion Application Notice is hereby given that on February 11, 2011, the Office of Thrift Supervision approved the..., NE., Atlanta, Georgia 30309. Dated: February 11, 2011. By the Office of Thrift Supervision. Sandra...

  10. Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles

    PubMed Central

    Manojlovic, Marija D

    2011-01-01

    Summary The one-pot hydrozirconation of allenes and nitriles followed by an in situ transmetalation of the allylzirconocene with dimethylzinc or zinc chloride provides functionalized homoallylic amines. An intramolecular version of this process leads to 3-aminotetrahydrofurans and 3-aminotetrahydropyrans. PMID:21804878

  11. Bis-phosphine allene ligand: coordination chemistry and preliminary applications in catalysis.

    PubMed

    Vanitcha, Avassaya; Damelincourt, Cecilia; Gontard, Geoffrey; Vanthuyne, Nicolas; Mouriès-Mansuy, Virginie; Fensterbank, Louis

    2016-05-21

    A 1,3-bis-diphenylphosphine allene can give rise to new coordination complexes with palladium, platinum and gold metals. These complexes were fully characterized by NMR, HRMS and X-ray diffraction analysis. For gold(i), the corresponding dinuclear complex has been used in a series of diagnostic catalytic reactions and gave promising preliminary results in asymmetric catalysis. PMID:27104618

  12. Astronauts Joseph Allen rides cherry picker over stowage area/work station

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Joseph P. Allen rides a cherry picker over to a stowage area/work station to wrap up extravehicular activity (EVA) duties above Earth. The cherry picker is a union of the mobile foot restraint and the remote manipulator system (RMS), controlled from inside Discovery's cabin. The Westar VI/PAM-D satellite is pictured secured in Discovery's cargo bay.

  13. Aryl-Allene Cyclization via a Hg(OTf)2-Catalytic Pathway.

    PubMed

    Yamamoto, Hirofumi; Ueda, Maho; Yamasaki, Naoto; Fujii, Akiyoshi; Sasaki, Ikuo; Igawa, Kazunobu; Kasai, Yusuke; Imagawa, Hiroshi; Nishizawa, Mugio

    2016-06-17

    Hg(OTf)2-catalyzed aryl-allene cyclization accompanied by formation of a quaternary carbon center has been realized. Deuterium-labeling experiments and computational modeling were used to propose a novel catalytic pathway involving direct H-transfer from the aromatic ring to the vinyl mercury moiety followed by mercury 1,2-migration. PMID:27232158

  14. All Together Now: Valerie Allen--U.S. Department of Energy

    ERIC Educational Resources Information Center

    Library Journal, 2005

    2005-01-01

    When Valerie Allen decided she did not want to be a Montessori teacher any longer, she began work on her MLIS. Immediately she learned concepts she could apply to her new job as information specialist for the Department of Energy's (DOE) Office of Scientific and Technical Information (OSTI) at Oak Ridge National Laboratory, TN. While the LIS…

  15. Rh(I)-Catalyzed Insertion of Allenes into C-C Bonds of Benzocyclobutenols.

    PubMed

    Zhao, Chunliang; Liu, Li-Chuan; Wang, Jing; Jiang, Chenran; Zhang, Qing-Wei; He, Wei

    2016-01-15

    Herein we report a Rh(I)-catalyzed two carbon insertion into C-C bonds of benzocyclobutenols by employing symmetrical and unsymmetrical allenes. This reaction provides rapid access to alkylidene tetralins bearing two adjacent stereogenic centers in good yields and diasteroselectivities. PMID:26727276

  16. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    SciTech Connect

    Jordanova, Vania K; Miyoshi, Y; Sakaguchi, K; Shiokawa, K; Evans, D S; Connors, M

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  17. [4+2] and [4+3] catalytic cycloadditions of allenes.

    PubMed

    López, Fernando; Mascareñas, José L

    2014-05-01

    This feature review describes the development of catalytic [4+2] and [4+3] cycloadditions of allenes, as efficient and practical methodologies for assembling six and seven-membered cyclic systems. The different methodologies have been classified depending on the type of key reactive intermediate that was proposed in the catalytic cycle. PMID:24643377

  18. Efficient access to cis-decalinol frameworks: copper(i)-catalyzed borylative cyclization of allene cyclohexanediones.

    PubMed

    Zhao, Yi-Shuang; Tang, Xiao-Qi; Tao, Jing-Chao; Tian, Ping; Lin, Guo-Qiang

    2016-05-11

    Cu-catalyzed borylative cyclization of allene cyclohexanediones has been described through a tandem β-borylation and intramolecular allylic addition process, affording borylated cis-decalinols with excellent yields and diastereoselectivities. A good enantioselectivity is also achieved in the asymmetric version. The hemiboronate group in the cyclization products could be subjected to several useful transformations. PMID:27116376

  19. A Test of Revised Scales for the Meyer and Allen (1991) Three-Component Commitment Construct.

    ERIC Educational Resources Information Center

    Culpepper, Robert A.

    2000-01-01

    Used confirmatory factor analysis with 2 samples (366 employees and 2,301 nurses) to compare the original and revised versions of the scales developed by J. Meyer and N. Allen (1991) to measure three- component commitment. Results show that substantially improved construct measurement is possible with relatively modest scale revisions. (SLD)

  20. Regioselective Allene Hydrosilylation Catalyzed by NHC Complexes of Nickel and Palladium

    PubMed Central

    Miller, Zachary D.; Li, Wei; Belderrain, Tomás R.; Montgomery, John

    2013-01-01

    Regioselective methods for allene hydrosilylation have been developed, with regioselectivity being governed primarily by choice of metal. Alkenylsilanes are produced via nickel catalysis with larger N-heterocyclic carbene ligands, and allylsilanes are produced via palladium catalysis with smaller N-heterocyclic carbene ligands. These complementary methods allow either regioisomeric product to be obtained with exceptional regiocontrol. PMID:24079389

  1. Free Pulp Transfer for Fingertip Reconstruction—The Algorithm for Complicated Allen Fingertip Defect

    PubMed Central

    Spyropoulou, Georgia-Alexandra; Shih, Hsiang-Shun

    2015-01-01

    Abstract Background: We present a review of all the cases of free toe pulp transfer and an algorithm for application of free pulp transfer in complicated Allen fingertip defect. Methods: Seventeen patients underwent free toe pulp transfer for fingertip reconstruction by the senior author. Twelve cases were Allen type II with oblique pulp defect, 4 were Allen type III, and 1 patient had 2 fingertip injuries classified both as type IV. According to the algorithm presented, for the type III defects where the germinal matrix is still preserved, we use free pulp transfer and nail bed graft to preserve the nail growth instead of toe to hand transfer. For the type IV injuries with multiple defects, a combination of web flap from both big toe and second toe is possible for 1-stage reconstruction. Results: All pulp flaps survived completely. Static 2-point discrimination ranged from 6 to 15 mm (mean: 10.5 mm). No patient presented dysesthesia, hyperesthesia, pain at rest, or cold intolerance. The donor site did not present any nuisances apart from partial skin graft loss in 3 cases. Conclusions: We tried to classify and modify the defects’ reconstruction according to Allen classification. Free toe pulp transfer is a “like with like” reconstruction that provides sensate, glabrous skin with good color and texture match for fingertip trauma, and minimal donor site morbidity compared with traditional toe to hand transfer. PMID:26894009

  2. Complex polycyclic scaffolds by metathesis rearrangement of Himbert arene/allene cycloadducts.

    PubMed

    Lam, Jonathan K; Schmidt, Yvonne; Vanderwal, Christopher D

    2012-11-01

    The intramolecular arene/allene cycloaddition first described 30 years ago by Himbert and Henn permits rapid access to strained polycyclic compounds. Alkene metathesis processes cleanly rearrange appropriately substituted cycloadducts into complex, functional-group-rich polycyclic lactams of potential utility for natural product synthesis and medicinal chemistry. PMID:23067058

  3. Improving the Collection of Student Accounts at Allen County Community College.

    ERIC Educational Resources Information Center

    Geffert, Barbara

    During the past several years, Allen County Community College has experienced a growing number of uncollected student accounts. In an effort to encourage timely payment of student charges, lower the number of students receiving payment deferments, increase cash flow at the beginning of each semester, and reduce the number of bad debts being…

  4. Project Cerberus: Flyby Mission to Pluto

    NASA Technical Reports Server (NTRS)

    Sivier, K.; Koepke, A.; Humphrey, Theodore W.; Elbel, Jeffrey P.; Hackett, Bruce E.; Kennedy, Ralph G.; Leo, Donald J.; Zimmerman, Shery A.

    1990-01-01

    The goal of the Cerberus Project was to design a feasible and cost-effective unmanned flyby mission to Pluto. The requirements in the request for proposal for an unmanned probe to Pluto are presented and were met. The design stresses proven technology that will avoid show stoppers which could halt mission progress. Cerberus also utilizes the latest advances in the spacecraft industry to meet the stringent demands of the mission. The topics covered include: (1) mission management, planning, and costing; (2) structures; (3) power and propulsion; (4) attitude, articulation, and control; (5) command, control, and communication; and (6) scientific instrumentation.

  5. Optimal low thrust geocentric transfer. [mission analysis computer program

    NASA Technical Reports Server (NTRS)

    Edelbaum, T. N.; Sackett, L. L.; Malchow, H. L.

    1973-01-01

    A computer code which will rapidly calculate time-optimal low thrust transfers is being developed as a mission analysis tool. The final program will apply to NEP or SEP missions and will include a variety of environmental effects. The current program assumes constant acceleration. The oblateness effect and shadowing may be included. Detailed state and costate equations are given for the thrust effect, oblateness effect, and shadowing. A simple but adequate model yields analytical formulas for power degradation due to the Van Allen radiation belts for SEP missions. The program avoids the classical singularities by the use of equinoctial orbital elements. Kryloff-Bogoliuboff averaging is used to facilitate rapid calculation. Results for selected cases using the current program are given.

  6. Skylab-3 Mission Onboard Photograph - Astronaut Bean on Ergometer

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This Skylab-3 onboard photograph shows Astronaut Allen Bean on the ergometer, breathing into the metabolic analyzer. Skylab's Metabolic Activity experiment (M171), a medical evaluation facility, was designed to measure astronauts' metabolic changes while on long-term space missions. The experiment obtained information on astronauts' physiological capabilities and limitations and provided data useful in the design of future spacecraft and work programs. Physiological responses to physical activity was deduced by analyzing inhaled and exhaled air, pulse rate, blood pressure, and other selected variables of the crew while they performed controlled amounts of physical work with a bicycle ergometer.

  7. Spectrophotometric probe

    DOEpatents

    Prather, W.S.; O'Rourke, P.E.

    1994-08-02

    A support structure is described bearing at least one probe for making spectrophotometric measurements of a fluid using a source of light and a spectrophotometer. The probe includes a housing with two optical fibers and a planoconvex lens. A sleeve bearing a mirror surrounds the housing. The lens is separated from the mirror by a fixed distance, defining an interior space for receiving a volume of the fluid sample. A plurality of throughholes extending through the sleeve communicate between the sample volume and the exterior of the probe, all but one hole bearing a screen. A protective jacket surrounds the probe. A hollow conduit bearing a tube is formed in the wall of the probe for venting any air in the interior space when fluid enters. The probe is held at an acute angle so the optic fibers carrying the light to and from the probe are not bent severely on emergence from the probe. 3 figs.

  8. Spectrophotometric probe

    DOEpatents

    Prather, William S.; O'Rourke, Patrick E.

    1994-01-01

    A support structure bearing at least one probe for making spectrophotometric measurements of a fluid using a source of light and a spectrophotometer. The probe includes a housing with two optical fibers and a planoconvex lens. A sleeve bearing a mirror surrounds the housing. The lens is separated from the mirror by a fixed distance, defining an interior space for receiving a volume of the fluid sample. A plurality of throughholes extending through the sleeve communicate between the sample volume and the exterior of the probe, all but one hole bearing a screen. A protective jacket surrounds the probe. A hollow conduit bearing a tube is formed in the wall of the probe for venting any air in the interior space when fluid enters. The probe is held at an acute angle so the optic fibers carrying the light to and from the probe are not bent severely on emergence from the probe.

  9. The navigation of space probes

    NASA Technical Reports Server (NTRS)

    Fliegel, H. F.; Ohandley, D. A.; Zielenbach, J. W.

    1974-01-01

    A new navigational method combining electronic measurement procedures and celestial mechanics makes it possible to conduct a space probe very close to a desired point in the neighborhood of a remote planet. Approaches for the determination of the position of the space probe in space are discussed, giving attention to the effects of errors in the employed data. The application of the navigational methods in a number of space missions is also considered.

  10. SPAS: Saturn Probe for Atmospheric Science

    NASA Astrophysics Data System (ADS)

    Li, L.; Jain, N.; Noevere, A. T.; Raghunandan, P.; Walsh, C.

    2014-06-01

    A parametric study was performed to design an atmospheric entry probe to Saturn in order to determine the gas giant’s composition and structure at depths greater than previous missions. Vehicle and trajectory parameters were chosen.

  11. Kepler Mission

    NASA Technical Reports Server (NTRS)

    Borucki, William J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The first step in discovering, the extent of life in our galaxy is to determine the number of terrestrial planets in the habitable zone (HZ). The Kepler Mission is a 0.95 m aperture photometer scheduled to be launched in 2006. It is designed to continuously monitor the brightness of 100,000 solar-like stars to detect the transits of Earth-size and larger planets. The depth and repetition time of transits provide the size of the planet relative to the star and its orbital period. When combined with ground-based spectroscopy of these stars to fix the stellar parameters, the true planet radius and orbit scale, hence the relation to the HZ are determined. These spectra are also used to discover the relationships between the characteristics of planets and the stars they orbit. In particular, the association of planet size and occurrence frequency with stellar mass and metallicity will be investigated. Based on the results of the current Doppler - velocity discoveries, over a thousand giant planets will be found. Information on the albedos and densities of those giants showing transits will be obtained. At the end of the four year mission, hundreds of terrestrial planets should be discovered in and near the HZ of their stars if such planets are common. A null result would imply that terrestrial planets in the HZ occur in less than 1% of the stars and that life might be quite rare.

  12. Payload missions integration

    NASA Technical Reports Server (NTRS)

    Mitchell, R. A. K.

    1983-01-01

    Highlights of the Payload Missions Integration Contract (PMIC) are summarized. Spacelab Missions no. 1 to 3, OSTA partial payloads, Astro-1 Mission, premission definition, and mission peculiar equipment support structure are addressed.

  13. Descope of the ALIA mission

    NASA Astrophysics Data System (ADS)

    Gong, Xuefei; Lau, Yun-Kau; Xu, Shengnian; Amaro-Seoane, Pau; Bai, Shan; Bian, Xing; Cao, Zhoujian; Chen, Gerui; Chen, Xian; Ding, Yanwei; Dong, Peng; Gao, Wei; Heinzel, Gerhard; Li, Ming; Li, Shuo; Liu, Fukun; Luo, Ziren; Shao, Mingxue; Spurzem, Rainer; Sun, Baosan; Tang, Wenlin; Wang, Yan; Xu, Peng; Yu, Pin; Yuan, Yefei; Zhang, Xiaomin; Zhou, Zebing

    2015-05-01

    The present work reports on a feasibility study commissioned by the Chinese Academy of Sciences of China to explore various possible mission options to detect gravitational waves in space alternative to that of the eLISA/LISA mission concept. Based on the relative merits assigned to science and technological viability, a few representative mission options descoped from the ALIA mission are considered. A semi-analytic Monte Carlo simulation is carried out to understand the cosmic black hole merger histories and the possible scientific merits of the mission options in probing the light seed black holes and their coevolution with galaxies in early Universe. The study indicates that, by choosing the armlength of the interferometer to be three million kilometers and shifting the sensitivity floor to around one-hundredth Hz, together with a very moderate improvement on the position noise budget, there are certain mission options capable of exploring light seed, intermediate mass black hole binaries at high redshift that are not readily accessible to eLISA/LISA, and yet the technological requirements seem to within reach in the next few decades for China.

  14. Intrepid: A Mission to Pluto

    NASA Technical Reports Server (NTRS)

    Behling, Michael; Buchman, Donald; Marcus, Andres; Procopis, Stephanie; Wassgren, Carl; Ziemer, Sarah

    1990-01-01

    A proposal for an exploratory spacecraft mission to Pluto/Charon system was written in response to the request for proposal for an unmannned probe to pluto (RFP). The design requirements of the RFP are presented and under the guidance of these requirements, the spacecraft Intrepid was designed. The RPF requirement that was of primary importance is the minimization of cost. Also, the reduction of flight time was of extreme importance because the atmosphere of Pluto is expected to collapse close to the Year 2020. If intrepid should arrive after the collapse, the mission would be a failure; for Pluto would be only a solid rock of ice. The topics presented include: (1) scientific instrumentation; (2) mission management, planning, and costing; (3) power and propulsion subsystem; (4) structural subsystem; (5) command, control, and communications; and (6) attitude and articulation control.

  15. Isolation and Characterization of Two Geometric Allene Oxide Isomers Synthesized from 9S-Hydroperoxylinoleic Acid by Cytochrome P450 CYP74C3

    PubMed Central

    Brash, Alan R.; Boeglin, William E.; Stec, Donald F.; Voehler, Markus; Schneider, Claus; Cha, Jin K.

    2013-01-01

    Specialized cytochromes P450 or catalase-related hemoproteins transform fatty acid hydroperoxides to allene oxides, highly reactive epoxides leading to cyclopentenones and other products. The stereochemistry of the natural allene oxides is incompletely defined, as are the structural features required for their cyclization. We investigated the transformation of 9S-hydroperoxylinoleic acid with the allene oxide synthase CYP74C3, a reported reaction that unexpectedly produces an allene oxide-derived cyclopentenone. Using biphasic reaction conditions at 0 °C, we isolated the initial products and separated two allene oxide isomers by HPLC at −15 °C. One matched previously described allene oxides in its UV spectrum (λmax 236 nm) and NMR spectrum (defining a 9,10-epoxy-octadec-10,12Z-dienoate). The second was a novel stereoisomer (UV λmax 239 nm) with distinctive NMR chemical shifts. Comparison of NOE interactions of the epoxy proton at C9 in the two allene oxides (and the equivalent NOE experiment in 12,13-epoxy allene oxides) allowed assignment at the isomeric C10 epoxy-ene carbon as Z in the new isomer and the E configuration in all previously characterized allene oxides. The novel 10Z isomer spontaneously formed a cis-cyclopentenone at room temperature in hexane. These results explain the origin of the cyclopentenone, provide insights into the mechanisms of allene oxide cyclization, and define the double bond geometry in naturally occurring allene oxides. PMID:23709224

  16. Venus Aerobot Multisonde Mission

    NASA Technical Reports Server (NTRS)

    Cutts, James A.; Kerzhanovich, Viktor; Balaram, J. Bob; Campbell, Bruce; Gershaman, Robert; Greeley, Ronald; Hall, Jeffery L.; Cameron, Jonathan; Klaasen, Kenneth; Hansen, David M.

    1999-01-01

    Robotic exploration of Venus presents many challenges because of the thick atmosphere and the high surface temperatures. The Venus Aerobot Multisonde mission concept addresses these challenges by using a robotic balloon or aerobot to deploy a number of short lifetime probes or sondes to acquire images of the surface. A Venus aerobot is not only a good platform for precision deployment of sondes but is very effective at recovering high rate data. This paper describes the Venus Aerobot Multisonde concept and discusses a proposal to NASA's Discovery program using the concept for a Venus Exploration of Volcanoes and Atmosphere (VEVA). The status of the balloon deployment and inflation, balloon envelope, communications, thermal control and sonde deployment technologies are also reviewed.

  17. Photonics on the Mission to Mars

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.

    2013-01-01

    Human missions to Mars present some unique challenges for photonics devices. These devices will have exposure to many different space environments. During assembly they will be exposed to the Earth orbiting environment. Upon departure they will need to function through the Earth's Van Allen Radiation Belt. While the general interplanetary environment is less challenging than the radiation belt, they will operate in this environment for 18 months, subject to sudden saturation from solar flares. These components must continue to function properly through these saturation events presenting quite a challenge to photonic components, both optical and electronic. At Mars, the orbital environment is more benign than the Earth's. Components used as part of the landing vehicles must also deal with the pervasive dust environment for 3 - 6 months. These assembly and mission execution environments provide every form of space environmental challenges to photonic components. This paper will briefly discuss each environment and the expectations on the components for successful operation over the life of the mission.

  18. Mission specification for three generic mission classes

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Mission specifications for three generic mission classes are generated to provide a baseline for definition and analysis of data acquisition platform system concepts. The mission specifications define compatible groupings of sensors that satisfy specific earth resources and environmental mission objectives. The driving force behind the definition of sensor groupings is mission need; platform and space transportation system constraints are of secondary importance. The three generic mission classes are: (1) low earth orbit sun-synchronous; (2) geosynchronous; and (3) non-sun-synchronous, nongeosynchronous. These missions are chosen to provide a variety of sensor complements and implementation concepts. Each mission specification relates mission categories, mission objectives, measured parameters, and candidate sensors to orbits and coverage, operations compatibility, and platform fleet size.

  19. Instrumentation and new missions

    NASA Astrophysics Data System (ADS)

    Nicastro, Fabrizio; Cash, W.; Bautz, M.; Elvis, M.

    2012-09-01

    A Soft X-Ray Grating Mission: Missing Baryons, AGN Outflows, Cosmic Feedback, Coronae Doppler Tomography, and much more | I will review the parameters of the new generation of high efficiency high resolution X-ray grating spectrometers, and present possible mission configurations, which would allow soft X-ray spectrometry to be performed on a large variety of astrophysical sources, with high diagnostic power. Resolving powers of R~4000 at 0.5 keV correspond to velocity accuracies of only few tens of km per second, sufficient to separate physical and dynamical phases of the low red shift photo-ionized and shock-heated inter-galactic medium (IGM), investigate mechanical and metal-feedback from galaxies to their surrounding circum- galactic medium (CGM) and IGM, study the physics and kinematics of AGN outflows, probing the dynamics of hot X-ray gas in clusters from their center to their virial radius and beyond, Doppler-mapping X-ray coronae of active stars.

  20. AXTAR: Mission Design Concept

    NASA Technical Reports Server (NTRS)

    Ray, Paul S.; Chakrabarty, Deepto; Wilson-Hodge, Colleen A.; Philips, Bernard F.; Remillard, Ronald A.; Levine, Alan M.; Wood, Kent S.; Wolff, Michael T.; Gwon, Chul S.; Strohmayer, Tod E.; Briggs, Michael S.; Capizzo, Peter; Fabisinski, Leo; Hopkins, Randall C.; Hornsby, Linda S.; Johnson, Les; Maples, C. Dauphne; Miernik, Janie H.; Thomas, Dan; DeGeronimo, Gianluigi

    2010-01-01

    The Advanced X-ray Timing Array (AXTAR) is a mission concept for X-ray timing of compact objects that combines very large collecting area, broadband spectral coverage, high time resolution, highly flexible scheduling, and an ability to respond promptly to time-critical targets of opportunity. It is optimized for sub-millisecond timing of bright Galactic X-ray sources in order to study phenomena at the natural time scales of neutron star surfaces and black hole event horizons, thus probing the physics of ultra-dense matter, strongly curved spacetimes, and intense magnetic fields. AXTAR s main instrument, the Large Area Timing Array (LATA) is a collimated instrument with 2 50 keV coverage and over 3 square meters effective area. The LATA is made up of an array of super-modules that house 2-mm thick silicon pixel detectors. AXTAR will provide a significant improvement in effective area (a factor of 7 at 4 keV and a factor of 36 at 30 keV) over the RXTE PCA. AXTAR will also carry a sensitive Sky Monitor (SM) that acts as a trigger for pointed observations of X-ray transients in addition to providing high duty cycle monitoring of the X-ray sky. We review the science goals and technical concept for AXTAR and present results from a preliminary mission design study

  1. Astronaut James Lovell checks body temperature with oral temperature probe

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Gemini 7 pilot Astronaut James A. Lovell Jr. has temperature check with oral temperature probe attached to his space suit during final preflight preparations for the Gemini 7 space mission. The temperature probe allows doctors to monitor astronauts body temperature at any time during the mission.

  2. National uranium resource evaluation: McAllen and Brownsville Quadrangles, Texas

    SciTech Connect

    Charepon, A J; Stauber, A J

    1982-06-01

    The McAllen and Brownsville Quadrangles, Texas, were evaluated to a depth of 1500 m to identify geologic environments and delineate areas favorable for uranium deposits. The environments were selected according to criteria established for the National Uranium Resource Evaluation program. Surface studies included investigations of uranium occurrences described in the literature, of locations of aerial radiometric anomalies, of surface exposures, and of locations of anomalous hydrogeochemical and stream-sediment reconnaissance data and collation of information on uranium exploration. Subsurface evaluation of selected geologic units was accomplished by using electric and gamma-ray well logs to construct maps and construct maps and cross sections. In the McAllen Quadrangle, an environment favorable for Texas roll-type sandstone uranium deposits is identified in 36 areas in the Goliad, Fleming-Oakville, Catahoula-Frio, and Whitsett Formations. All other units in both quadrangles are considered unfavorable.

  3. Arthroscopic Medial Meniscus Posterior Root Fixation Using a Modified Mason-Allen Stitch.

    PubMed

    Chung, Kyu Sung; Ha, Jeong Ku; Ra, Ho Jong; Kim, Jin Goo

    2016-02-01

    A complete radial tear of the meniscus posterior root, which can effectively cause a state of total meniscectomy via loss of hoop tension, requires that the torn root be repaired. Several methods have been used to repair medial meniscus posterior root tears, most of which are based on a simple stitch technique that is known to have stitch-holding strength. We applied a modified version of the Mason-Allen stitch technique, which is recognized as a method for rotator cuff repair surgery because its locking effect overcomes the potential weakness of simple stitches. This article introduces the medial meniscus posterior root tears repair procedure based on a modified Mason-Allen stitch technique in which 2 strands (i.e., 1 simple horizontal and 1 simple vertical stitch) are used. PMID:27073778

  4. Arthroscopic Medial Meniscus Posterior Root Fixation Using a Modified Mason-Allen Stitch

    PubMed Central

    Chung, Kyu Sung; Ha, Jeong Ku; Ra, Ho Jong; Kim, Jin Goo

    2016-01-01

    A complete radial tear of the meniscus posterior root, which can effectively cause a state of total meniscectomy via loss of hoop tension, requires that the torn root be repaired. Several methods have been used to repair medial meniscus posterior root tears, most of which are based on a simple stitch technique that is known to have stitch-holding strength. We applied a modified version of the Mason-Allen stitch technique, which is recognized as a method for rotator cuff repair surgery because its locking effect overcomes the potential weakness of simple stitches. This article introduces the medial meniscus posterior root tears repair procedure based on a modified Mason-Allen stitch technique in which 2 strands (i.e., 1 simple horizontal and 1 simple vertical stitch) are used. PMID:27073778

  5. A Versatile Room-Temperature Route to Di- and Trisubstituted Allenes Using Flow-Generated Diazo Compounds**

    PubMed Central

    Poh, Jian-Siang; Tran, Duc N; Battilocchio, Claudio; Hawkins, Joel M; Ley, Steven V

    2015-01-01

    A copper-catalyzed coupling reaction between flow-generated unstabilized diazo compounds and terminal alkynes provides di- and trisubstituted allenes. This extremely mild and rapid transformation is highly tolerant of several functional groups. PMID:26013774

  6. Radiological health risks for exploratory class missions in space.

    PubMed

    Nachtwey, D S; Yang, T C

    1991-01-01

    Crewmembers on missions to the Moon or Mars will be unavoidably exposed to ionizing radiation as they pass through the Van Allen belts and the Galactic Cosmic Ray (GCR) flux. There is the possibility for exposure to proton radiation from Solar Particle Events (SPE). Using absorbed doses and ICRP 26, Linear Energy Transfer (LET) -dependent quality factors, the following dose-equivalents are estimated: In a spacecraft with 0.75 cm aluminum walls (2 g/cm2) at solar minimum, the lunar round trip dose-equivalent is less than 0.05 Sv. During a Mars mission the estimated dose-equivalents are: outbound (Van Allen Belts) <0.02 Sv; Earth to Mars (205 days exposure to free space GCR) 0.32 Sv; 30 days on the Martian surface (GCR) 0.023 Sv; Mars to Earth (225 days exposure to free space) 0.35 Sv; and through the Van Allen Belts 0.02 Sv. Conventionally, the total of 0.73 Sv over 460 days could be expected to increase the risk of cancer mortality in a 35-year old male astronaut by about one percent. However three-fourths of the dose-equivalent in free space is contributed by high LET heavy ions (Z > or = 3) and target fragments with average quality factors of 10.3 and 20 respectively. The biological effectiveness of these radiations is poorly understood; so the quality factors are set at conservatively very high values. The entire concept of absorbed dose/quality factor/dose-equivalent as applied to GCR must be reconsidered. PMID:11537128

  7. Einstein Inflationary Probe (EIP)

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary

    2004-01-01

    I will discuss plans to develop a concept for the Einstein Inflation Probe: a mission to detect gravity waves from inflation via the unique signature they impart to the cosmic microwave background (CMB) polarization. A sensitive CMB polarization satellite may be the only way to probe physics at the grand-unified theory (GUT) scale, exceeding by 12 orders of magnitude the energies studied at the Large Hadron Collider. A detection of gravity waves would represent a remarkable confirmation of the inflationary paradigm and set the energy scale at which inflation occurred when the universe was a fraction of a second old. Even a strong upper limit to the gravity wave amplitude would be significant, ruling out many common models of inflation, and pointing to inflation occurring at much lower energy, if at all. Measuring gravity waves via the CMB polarization will be challenging. We will undertake a comprehensive study to identify the critical scientific requirements for the mission and their derived instrumental performance requirements. At the core of the study will be an assessment of what is scientifically and experimentally optimal within the scope and purpose of the Einstein Inflation Probe.

  8. Neptune Polar Orbiter with Probes

    NASA Technical Reports Server (NTRS)

    Bienstock, Bernard; Atkinson, David; Baines, Kevin; Mahaffy, Paul; Steffes, Paul; Atreya, Sushil; Stern, Alan; Wright, Michael; Willenberg, Harvey; Smith, David; Frampton, Robert; Sichi, Steve; Peltz, Leora; Masciarelli, James; VanCleve, Jeffey

    2005-01-01

    The giant planets of the outer solar system divide into two distinct classes: the gas giants Jupiter and Saturn, which consist mainly of hydrogen and helium; and the ice giants Uranus and Neptune, which are believed to contain significant amounts of the heavier elements oxygen, nitrogen, and carbon and sulfur. Detailed comparisons of the internal structures and compositions of the gas giants with those of the ice giants will yield valuable insights into the processes that formed the solar system and, perhaps, other planetary systems. By 2012, Galileo, Cassini and possibly a Jupiter Orbiter mission with microwave radiometers, Juno, in the New Frontiers program, will have yielded significant information on the chemical and physical properties of Jupiter and Saturn. A Neptune Orbiter with Probes (NOP) mission would deliver the corresponding key data for an ice giant planet. Such a mission would ideally study the deep Neptune atmosphere to pressures approaching and possibly exceeding 1000 bars, as well as the rings, Triton, Nereid, and Neptune s other icy satellites. A potential source of power would be nuclear electric propulsion (NEP). Such an ambitious mission requires that a number of technical issues be investigated, however, including: (1) atmospheric entry probe thermal protection system (TPS) design, (2) probe structural design including seals, windows, penetrations and pressure vessel, (3) digital, RF subsystem, and overall communication link design for long term operation in the very extreme environment of Neptune's deep atmosphere, (4) trajectory design allowing probe release on a trajectory to impact Neptune while allowing the spacecraft to achieve a polar orbit of Neptune, (5) and finally the suite of science instruments enabled by the probe technology to explore the depths of the Neptune atmosphere. Another driving factor in the design of the Orbiter and Probes is the necessity to maintain a fully operational flight system during the lengthy transit time

  9. AIDA: The Asteroid Impact & Deflection Assessment Mission

    NASA Astrophysics Data System (ADS)

    Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.

    2013-09-01

    The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL's Double Asteroid Redirection Test (DART) and the European Space Agency's Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system's dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.- It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].

  10. Planetary mission summaries. Volume 1: Introduction and overview

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Tabular synopses of twelve missions are presented along with the Mariner Jupiter/Saturn 1977 mission for comparison. Mission definitions considered include: Mars Polar Orbiter; Mars Surface Sample Return; Mars Rover; Marine Jupiter/Uranus 1979 with Uranus Entry Probe; Mariner Jupiter Orbiter; Mariner Mercury Orbiter 1978; Early Mariner Comet Flyby Solar Electric Encke Slow Flyby; Mariner Encke Ballistic Flyby; Solar Electric Encke Rendezvous 1981; Venus Orbital Imaging Radar; Solar Electric Out-of-the-Eliptic Probe 1979. Technical conclusions of mission studies are given in order that these results may interact with the broader questions of scope, pace, and priorities in the planetary exploration program.

  11. Functional analysis of allene oxide cyclase, MpAOC, in the liverwort Marchantia polymorpha.

    PubMed

    Yamamoto, Yusuke; Ohshika, Jun; Takahashi, Tomohiro; Ishizaki, Kimitsune; Kohchi, Takayuki; Matusuura, Hideyuki; Takahashi, Kosaku

    2015-08-01

    12-Oxo-phytodienoic acid (OPDA) is an intermediate in jasmonic acid (JA) biosynthesis. OPDA exerts JA-dependent and JA-independent biological effects; therefore, it is considered a signaling molecule in flowering plants. OPDA is induced by bacterial infection and wounding and inhibits growth in the moss Physcomitrella patens. The functions of OPDA and allene oxide cyclase (AOC) in the liverwort Marchantia polymorpha were explored, which represents the most basal lineage of extant land plants. The analysis of OPDA showed that it is present in M. polymorpha and is increased by wounding. OPDA has been suggested to be involved in the response to environmental stresses. Moreover, OPDA showed growth inhibitory activity in M. polymorpha. Nonetheless JA in M. polymorpha was not found in this study. AOC synthesizes OPDA from an unstable allene oxide. A database search of the M. polymorpha genome identified only a putative gene encoding allene oxide cyclase (MpAOC). Recombinant MpAOC showed AOC activity similar to that in flowering plants. MpAOC was localized to chloroplasts, as in flowering plants. Expression of MpAOC was induced by wounding and OPDA treatment, and positive feedback regulation of OPDA was demonstrated in M. polymorpha. Overexpression of MpAOC increased the endogenous OPDA level and suppressed growth in M. polymorpha. These results indicate the role of OPDA as a signaling molecule regulating growth and the response to wounding in the liverwort M. polymorpha. PMID:25892411

  12. Allen Brain Atlas-Driven Visualizations: a web-based gene expression energy visualization tool.

    PubMed

    Zaldivar, Andrew; Krichmar, Jeffrey L

    2014-01-01

    The Allen Brain Atlas-Driven Visualizations (ABADV) is a publicly accessible web-based tool created to retrieve and visualize expression energy data from the Allen Brain Atlas (ABA) across multiple genes and brain structures. Though the ABA offers their own search engine and software for researchers to view their growing collection of online public data sets, including extensive gene expression and neuroanatomical data from human and mouse brain, many of their tools limit the amount of genes and brain structures researchers can view at once. To complement their work, ABADV generates multiple pie charts, bar charts and heat maps of expression energy values for any given set of genes and brain structures. Such a suite of free and easy-to-understand visualizations allows for easy comparison of gene expression across multiple brain areas. In addition, each visualization links back to the ABA so researchers may view a summary of the experimental detail. ABADV is currently supported on modern web browsers and is compatible with expression energy data from the Allen Mouse Brain Atlas in situ hybridization data. By creating this web application, researchers can immediately obtain and survey numerous amounts of expression energy data from the ABA, which they can then use to supplement their work or perform meta-analysis. In the future, we hope to enable ABADV across multiple data resources. PMID:24904397

  13. Ion-molecule reactions in unsaturated hydrocarbons - Allene, propyne, diacetylene, and vinylacetylene

    NASA Technical Reports Server (NTRS)

    Anicich, V. G.; Blake, G. A.; Huntress, W. T., Jr.; Kim, J. K.; Mcewan, M. J.

    1984-01-01

    Ion-molecule reactions in allene, propyne, diacetylene, and vinylacetylene (1-buten-3-yne) have been studied at near-thermal energies by the technique of ion cyclotron resonance mass spectrometry. Rate coefficients and branching ratios are reported for the reactions of C3Hn(+) (n = 1-4) with allene and propyne and for the reactions of C4Hn(+) (n = 0-5) with diacetylene and vinylacetylene. Branching ratios are also given for the reactions of C4Hn(+), C5Hn and C6Hn(+) with propyne and for reactions of C6Hn(+) with diacetylene and vinylacetylene. More than 90 percent of the reactive channels lead to product ions having a larger carbon skeleton than the reactant ion. Evidence for ions with the same m/e ratio having differing reactivities was obtained for C3Hn(+), C6H7(+), and C7H7(+). Ion reaction sequences in allene and propyne were followed at higher pressures (0.0001 torr) to investigate secondary, tertiary, and higher order processes.

  14. Low Cost Mission Operations Workshop. [Space Missions

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The presentations given at the Low Cost (Space) Mission Operations (LCMO) Workshop are outlined. The LCMO concepts are covered in four introductory sections: Definition of Mission Operations (OPS); Mission Operations (MOS) Elements; The Operations Concept; and Mission Operations for Two Classes of Missions (operationally simple and complex). Individual presentations cover the following topics: Science Data Processing and Analysis; Mis sion Design, Planning, and Sequencing; Data Transport and Delivery, and Mission Coordination and Engineering Analysis. A list of panelists who participated in the conference is included along with a listing of the contact persons for obtaining more information concerning LCMO at JPL. The presentation of this document is in outline and graphic form.

  15. The Space Shuttle Columbia clears the tower to begin the mission. The liftoff occurred on schedule

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-75 LAUNCH VIEW --- The Space Shuttle Columbia clears the tower to begin the mission. The liftoff occurred on schedule at 3:18:00 p.m. (EST), February 22, 1996. Visible at left is the White Room on the orbiter access arm through which the flight crew had entered the orbiter. Onboard Columbia for the scheduled two-week mission were astronauts Andrew M. Allen, commander; Scott J. Horowitz, pilot; Franklin R. Chang-Diaz, payload commander; and astronauts Maurizio Cheli, Jeffrey A. Hoffman and Claude Nicollier, along with payload specialist Umberto Guidioni. Cheli and Nicollier represent the European Space Agency (ESA), while Guidioni represents the Italian Space Agency (ASI).

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  17. The Pascal Discovery Mission: A Mars Climate Network Mission

    NASA Technical Reports Server (NTRS)

    Haberle, R. M.; Catling, D. C.; Chassefiere, E.; Forget, F.; Hourdin, F.; Leovy, C. B.; Magalhaes, J.; Mihalov, J.; Pommereau, J. P.; Murphy, J. R.

    2000-01-01

    The climate of Mars is a major focus of Mars exploration. With the loss of MCO, however, it remains uncertain how it will be achieved. We argue that a truly dedicated climate mission to Mars should have both orbital and landed components, and that these should operate simultaneously for at least 1 Mars year if not longer. Pascal is a Discovery mission that emphasizes the landed component. Its principal goal is to establish a network of 24 small weather stations on the surface of Mars that will operate for 2 Mars years, with an extended mission option for an additional 8 Mars years bringing the total mission lifetime up to 10 Mars years. The stations will collect hourly measurements of pressure, temperature, and optical depth. After delivering the probes to Mars, Pascal's carrier spacecraft will go into an elliptical orbit which will serve as a relay for the landers, and a platform for synoptic imaging. These simultaneous measurements from the surface and from orbit will allow us to characterize the planet's general circulation and its interaction with the dust, water, and CO2 cycles. During entry, descent, and landing, each of Pascal's 24 probes will also measure the temperature structure of the atmosphere and acquire images of the surface. These data will allow us to determine the global structure of the atmosphere between 15 and 130 km, and characterize the local terrain to help interpret the landed data. The descent images are part of Pascal's outreach program, as the probe camera system will be developed by faculty-supervised student project. The intent is to generate enthusiasm for the Pascal mission by directly involving students. Pascal will be launched on a Delta II-7925 in August of 2005. A type I trajectory will deliver Pascal to Mars in January of 2006. On approach, the three-axis stabilized carrier spacecraft will spring deploy the Pascal probes in 4 separate salvo's of 6 each. Global coverage is achieved with small time-of-arrival adjustments in

  18. The Pascal Discovery Mission: A Mars Climate Network Mission

    NASA Technical Reports Server (NTRS)

    Haberle, Robert M.; Catling, D. C.; Chassefiere, E.; Forget, F.; Hourdin, F.; Leovy, C. B.; Magalhaes, J.; Mihalov, J.; Pommereau, J. P.; Murphy, J. R.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The climate of Mars is a major focus of Mars exploration. With the loss of MCO, however, it remains uncertain how it will be achieved. We argue that a truly dedicated climate mission to Mars should have both orbital and landed components, and that these should operate simultaneously for at least I Mars year if not longer. Pascal is Discovery mission that emphasizes the landed component. Its principal goal is to establish a network of 24 small weather stations on the surface of Mars that will operate for 2 Mars years, with an extended mission option for an additional 8 Mars years bringing the total mission lifetime up to 10 Mars years. The stations will collect hourly measurements of pressure, temperature, and optical depth. After delivering the probes to Mars, Pascal's carrier spacecraft will go into an elliptical orbit which will serve as a relay for the landers, and a platform for synoptic imaging. These simultaneous measurements from the surface and from orbit will allow us to characterize the planet's general circulation and its interaction with the dust, water, and CO2 cycles. During entry, descent, and landing, each of Pascal's 24 probes will also measure the temperature structure of the atmosphere and acquire images of the surface. These data will allow us to determine the global structure of the atmosphere between 15 and 130 km, and characterize the local terrain to help interpret the landed data. The descent images are part of Pascal's outreach program, as the probe camera system will be developed by faculty-supervised student project. The intent is to generate enthusiasm for the Pascal mission by directly involving students. Pascal will be launched on a Delta 11-7925 in August of 2005. A type I trajectory will deliver Pascal to Mars in January of 2006. On approach, the three-axis stabilized carrier spacecraft will spring deploy the Pascal probes in 4 separate salvo's of 6 each. Global coverage is achieved with small time-of-arrival adjustments in between

  19. On the Control of Van Allen Radiation Belt Morphology by Coupling to the Plasmasheet: How Quickly, How Deeply, and How Strongly?

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Ozeke, Louis

    2016-07-01

    Here we examine the speed, strength and depth of the coupling between dynamical variations of the electron flux at the outer boundary and that in the heart of the radiation belts. Using ULF wave radial diffusion as an exemplar, we show how changing boundary conditions can completely change belt morphology even under conditions of identical wave power. In the case of ULF wave radial diffusion, whether there is a new source population or a sink of electron flux at the outer plasmasheet boundary can generate a completely opposite response which reaches deep into the belt even under identical ULF wave conditions. Very significantly, here we show that such coupling can occur on timescales much faster than previously thought, being as short as one hour or less between the outer boundary and L-shells in the heart of the belts at L˜4 and significantly less than the L-shell revisit time obtained from elliptically orbiting satellites such as the Van Allen Probes. We underline the importance of such boundary condition effects when seeking to identify the physical processes which explain the dominant behaviour of the Van Allen belts. We further examine implications for reaching science closure in identifying causality in radiation belt wave-particle dynamics, and in relation to observational requirements for accurate radiation belt forecasting. Overall we argue in general that the importance of boundary conditions is sometimes overlooked in comparison to the pursuit of (ever) increasingly accurate estimates of wave power and other wave properties used in empirical representations of wave transport and diffusion rates.

  20. The ADAHELI Solar Mission

    NASA Astrophysics Data System (ADS)

    Berrilli, F.; Velli, M.; Roselli, L.; Bigazzi, A.; Moretti, P. F.; Romoli, M.; Orsini, S.; Cavallini, F.; Greco, V.; Carbone, V.; Consolini, G.; Di Mauro, M. P.; Ermolli, I.; Pietropaolo, E.; Romano, P.; Ventura, P.; White, S. M.; Zuccarello, F.; Cauzzi, G.; Valdettaro, L.

    2008-09-01

    ADAHELI (Advanced Astronomy for HELIOphysics) is an Italian Space project for the investigation of solar photospheric and chromospheric dynamics, via high-resolution spectro-polarimetric observations in the near-infrared spectral range. The mission has been financed for phase A study in the framework of ASI Italian Space Agency Small Missions Program call of September 2007. Four fields have been selected to highlight the specific benefits of ADAHELI scientific payload: 1) Photospheric and chromospheric dynamics and structure, 2) Emergence and evolution of solar active regions and solar irradiance, 3) Chromospheric and corona heating and turbulence, 4) Solar flares in the millimeter wavelength region. The principal science instrument, ISODY, is a 50 cm solar telescope equipped with an innovative Focal Plane Suite composed of a spectro-polarimetric imager, based upon two Fabry-Perot interferometers operating in the NIR regions around 845nm and 1083nm, a broad band imager, and a correlation tracker used as image stabilization system. Designed Mission Profiles for ADAHELI intend to achieve continuous high-spectral and spatial resolution observations of the Sun for a routine duration of 4 hours with a goal to be extended to 24 hours. ADAHELI also carries MIOS, a millimeter wavelengths radiometer operating at around 90 GHz for flare detection. The ADAHELI payload's instrument suite integrates and complements, without overlap, the present major objectives of ESA, NASA and the International Living with a Star program, in particular Solar Dynamics Observatory, PICARD, Solar Orbiter, and the Solar Probe missions. Proposals for optional instruments are also under evaluation: DIMMI-2h, a double channel MOF based full disk imager operating at 589nm and 770nm, allowing high temporal resolution velocity and magnetic field measurements; EISR a two channel spectrometer operating in the 50-130 nm wavelength range, and NPA, an in-situ Neutral Particle Analyzer to detect Energetic

  1. JIMO Delivery and Support of a Jupiter Deep Entry Probe

    NASA Technical Reports Server (NTRS)

    Spilker, T. R.; Young, R. E.

    2003-01-01

    The 2003 Solar System Exploration Decadal Survey ('SSEDS') emphasizes the significant science available from Jupiter deep entry probes. Studies performed at JPL this year identified a mission design that would allow JIMO to deliver and support one or more entry probes that reach the 100-bar level in Jupiter's atmosphere, with relatively minor modifications to JIMO s preliminary mission design. Notably, the icy moon tour mission design, beginning with Callisto approach, is unaffected. This proposed mission design would offer the option of adding a rich new set of high-priority SSEDS science objectives to the planned JIMO mission for a relatively small investment.

  2. [A study on Horace N. Allen's medicine and recognition of Korean body].

    PubMed

    Lee, Young Ah

    2011-12-31

    Je Jung Won was the first modern-style Government hospital built by the Korean King Ko-Jong in April 1885, and it was the medical missionary Horace Newton Allen(1858~1932) who made one of the greatest contributions to the establishment of the hospital. Allen was an American missionary. He graduated from Ohio Wesleyan University with a degree in theology in 1881, and completed one-yearcourse at Miami Medical College. In Korea and America he worked as a physician, a missionary, an American diplomatic minister to Korea and a Korean minister's secretary to America. While acting as a mediator between Korea and America, he knew and recorded the domestic and foreign situation of Korea during Gaehwagi(the civilized and enlightened age). Thus to study him is to understand Korea's Gaehwagi as well as to research American medical missionaries. During his stay in Korea(1884~1905), Allen steadily wrote diaries and letters about Korean politics, diplomacy, society, culture, and medicine. Thus his public/private record through diaries and letters(the quantity of these materials amounts to several thousands) supplements the Korean early modern era's historical record. However, until now these materials have received little scholarly attention from researchers except for a few historians of missionary work between Korea and America, or of Korean modern medicine. I intended to use these materials to suggest a new perspective on the study of Korean Gaehwagi. Allen, along with John W. Heron, who came to Seoul on June 21st 1885, treated about 10,460 Korean patients in the first year of the opening of JeJungWon. They made "the first annual report of the Korean Government Hospital". This report explained how Allen and Heron regarded and treated Korean patients. Allen's diaries, letters and other writings offer a realistic view of how the western people actually recognized the Korean people at that time. As a western doctor, Allen had an ambivalent attitude toward Korean medical concepts

  3. Prospects for Future Helioseismology Missions

    NASA Astrophysics Data System (ADS)

    Scherrer, Philip H.

    The progress afforded by present and past helioseismology missions has been the topic of this and numerous previous conferences. The primary conclusion of the 1983 NASA study on prospects for solar oscillations have been basically confirmed. That is, part of the job can be done on the ground but a significant part can only be done from space. While we have made significant progress, it is also clear that additional opportunities to use helioseismic techniques to better understand stellar interiors remain. Recent advances in local helioseismology in particular point to additional observing requirements. These include larger field of view at high resolution in order to follow magnetic region development, longer baselines in longitude to probe the bottom of the convection zone and below, and a high latitude vantage point to examine processes near the rotation axis. Several possible missions have been discussed recently to address these issues. They include SONAR, Farside Observer, Solar Polar Imager, and Solar Probe. The basic concepts of these missions will be discussed along with the continuing role for enhanced ground based observations.

  4. Mission Design for the Innovative Interstellar Explorer Vision Mission

    NASA Technical Reports Server (NTRS)

    Fiehler, Douglas I.; McNutt, Ralph L.

    2005-01-01

    The Innovative Interstellar Explorer, studied under a NASA Vision Mission grant, examined sending a probe to a heliospheric distance of 200 Astronomical Units (AU) in a "reasonable" amount of time. Previous studies looked at the use of a near-Sun propulsive maneuver, solar sails, and fission reactor powered electric propulsion systems for propulsion. The Innovative Interstellar Explorer's mission design used a combination of a high-energy launch using current launch technology, a Jupiter gravity assist, and electric propulsion powered by advanced radioisotope power systems to reach 200 AU. Many direct and gravity assist trajectories at several power levels were considered in the development of the baseline trajectory, including single and double gravity assists utilizing the outer planets (Jupiter, Saturn, Uranus, and Neptune). A detailed spacecraft design study was completed followed by trajectory analyses to examine the performance of the spacecraft design options.

  5. CDMA with interference cancellation for multiprobe missions

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Simon, M. K.

    1995-01-01

    Code division multiple-access spread spectrum has been proposed for use in future multiprobe/multispacecraft missions. This article considers a general parallel interference-cancellation scheme that significantly reduces the degradation effect of probe (user) interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each probe (user) the total interference produced by the remaining most reliably received probes (users) accessing the channel. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of probe/spacecraft interference. The one-stage interference cancellation was analyzed for two types of tentative decision devices, namely, hard and null zone decisions. Simulation results are given for one- and two-stage interference cancellation for equal as well as unequal received power probes.

  6. Inspire: A Mars Network Science Mission

    NASA Astrophysics Data System (ADS)

    Voirin, T.; Larranaga, J.; Taylor, G.; Sanchez Perez, J. M.; Prost, J. P.; Cavel, C.; Falkner, P.

    2014-06-01

    INSPIRE is a Mars Network Science mission which is been studied by ESA in the frame of its Mars Robotic Exploration Program. It consists of three probes performing a direct entry on Mars for geophysics and meteorology science over one full martian year.

  7. The Interstellar Heliopause Probe

    NASA Astrophysics Data System (ADS)

    Lyngvi, A.; Falkner, P.; Peacock, A.

    The Interstellar Heliopause Probe (IHP) is one of four Technology Reference Missions (TRM) introduced by the Planetary Exploration Studies Section of the Science Payload & Advanced Concepts Office (SCI-A) at ESA. The overall purpose of the TRMs is to focus the development of strategically important technologies of likely relevance to future science missions. This is accomplished through the study of several technologically demanding and scientifically interesting missions, which are currently not part of the ESA science programme. The TRM baseline uses small satellites (< 200kg), with highly miniaturized and highly integrated payload suites. The motivation for this is to use low resource spacecraft in a phased approach, which will reduce the risk and cost, compared to a single, high resource mission. Equipped with a Highly Integrated Payload Suite (HIPS) the IHP will answer scientific questions concerning the nature of the interstellar medium, how the interstellar medium affects our solar system and how the solar system impacts the interstellar medium. The HIPS, which is a standard element in all TRMs miniaturize through resource reduction, by using miniaturized components and sensors, and by sharing common structures and payload functionality. To achieve the scientific requirements of the mission the spacecraft is to leave the solar system as close to the heliosphere nose as possible and reach a distance of 200 AU from the Sun within 25 years. The requirement of all TRMs is to use a Souyz-Fregat version 2B or equivalent low cost launch vehicle. With this constraint no current propulsion system is capable of delivering the necessary mass to the final destination. Technologies are therefore needed to enable this mission. The current alternatives are using nuclear propulsion, either with radioisotope or reactor power system or solar sailing. All these alternatives are currently being investigated. Other challenges exist as well such as designing a communication link

  8. Mechanistic Studies on Au(I)-Catalyzed [3,3]-Sigmatropic Rearrangements using Cyclopropane Probes

    PubMed Central

    Mauleón, Pablo; Krinsky, Jamin L.

    2009-01-01

    A comparative study of the Au(I)-catalyzed [3,3]-sigmatropic rearrangement of propargylic esters and propargyl vinyl ethers is described. Stereochemically defined cyclopropanes are employed as mechanistic probes to provide new synthetic and theoretical data concerning the reversibility of this type of rearrangement. Factors controlling the structure-reactivity relationship of Au(I)-coordinated allenes have been examined, thereby allowing for controlled access to orthogonal reactivity. PMID:19275228

  9. Ion currents to cylindrical Langmuir probes for finite ion temperature values: Experimental

    SciTech Connect

    Ballesteros, J.; Palop, J.I.F.; Colomer, V.; Hernandez, M.A.

    1995-12-31

    A new theoretical model about the ion currents to a cylindrical probe has been developed which takes into account the influence of a finite ion temperature value. The ABR (Allen, Boyd and Reynolds) model, which considers only radial motion for the positive ions, is recovered in the limit of cold ions. In this paper we axe going to show the experimental ion currents obtained in a plasma in which the positive ion temperature effect cannot be neglected.

  10. Optical probe

    DOEpatents

    Hencken, Kenneth; Flower, William L.

    1999-01-01

    A compact optical probe is disclosed particularly useful for analysis of emissions in industrial environments. The instant invention provides a geometry for optically-based measurements that allows all optical components (source, detector, rely optics, etc.) to be located in proximity to one another. The geometry of the probe disclosed herein provides a means for making optical measurements in environments where it is difficult and/or expensive to gain access to the vicinity of a flow stream to be measured. Significantly, the lens geometry of the optical probe allows the analysis location within a flow stream being monitored to be moved while maintaining optical alignment of all components even when the optical probe is focused on a plurality of different analysis points within the flow stream.

  11. The Imminent Swift MIDEX Mission

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil

    2004-01-01

    Swift is a NASA MIDEX mission that is in development for launch in Fall 2004. It is a multiwavelength observatory for transient astronomy. The goals of the mission are to determine the origin of gamma-ray bursts and their afterglows and use bursts to probe the early Universe. The mission will also perform a hard x-ray survey at the 1 milliCrab level and will continuously monitor the sky for transients. A wide-field gamma-ray camera will detect more than a hundred GRBs per year to 3 times fainter than BATSE. Sensitive narrow-field X-ray and UV/optical telescopes will be pointed at the burst. location in 20 to 70 sec by an autonomously controlled "swift" spacecraft. For each burst, arcsec positions will be determined and optical/UV/X-ray/gamma-ray spectrophotometry performed. The instrumentation is a combination of existing flight-spare hardware and design from XMM and Spectrum-X/JET-X contributed by collaborators in the UK and Italy and development of a coded-aperture camera with a large-area (approximately 0.5 square meter) CdZnTe detector array. The ground station in Malindi is contributed by the Italian Space Agency. The instruments have now completed their fabrication phase and are currently being integrated on the observatory for final testing. Key components of the mission are vigorous follow-up and outreach programs to engage the astronomical community and public in Swift.

  12. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

    DOE PAGESBeta

    Hartley, D. P.; Chen, Y.; Kletzing, C. A.; Denton, M. H.; Kurth, W. S.

    2015-02-17

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1–0.9 fce). Results from this study indicate that the calculated wavemore » intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10⁻³ nT², using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.« less

  13. Field-Aligned Electron Events Observed in the Radiation Belts by the HOPE Instruments aboard the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Lejosne, S.; Agapitov, O. V.; Mozer, F.

    2015-12-01

    Field-aligned electron events (FAEs) are defined as events having the ratio of field-aligned to perpendicular flux greater than three. Time Domain Structures (TDS) are known to produce FAEs. Whistler and ECH waves are other possible candidates. Our objective is to derive the general features of the FAEs, to identify their driving mechanisms and to evaluate the importance of the different mechanisms. More than two years of measurements by the Helium Oxygen Proton Electron mass spectrometer and the Electric Field and Waves experiment are analyzed to identify low-energy (100eV-50keV) FAEs and to quantify the concurrent electric and magnetic wave components. We also peek at the observable waveforms with bursts of high-time resolution measurements. From statistical analysis and case studies, we suggest in particular that TDS cause field-alignment of ~300eV electrons in the pre-midnight sector while chorus waves cause field-alignment of electrons of ~10keV in the morning sector of the outer belt.

  14. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

    PubMed Central

    Hartley, D P; Chen, Y; Kletzing, C A; Denton, M H; Kurth, W S

    2015-01-01

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1–0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10−3 nT2, using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons. PMID:26167444

  15. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

    SciTech Connect

    Hartley, D. P.; Chen, Y.; Kletzing, C. A.; Denton, M. H.; Kurth, W. S.

    2015-02-17

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1–0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10⁻³ nT², using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.

  16. Iterative Calculation of Plasma Density from a Cylindrical Probe Characteristic

    NASA Astrophysics Data System (ADS)

    Xu, Zhenfeng; Lu, Wenqi

    2013-08-01

    A novel method is proposed for treating cylindrical probe characteristics to obtain plasma density. The method consists of exponential extrapolation of the transitional part of the I-V curve to the floating potential for the ion saturation current, other than the existing theories which use the ion branch, and an iterative sheath thickness correction procedure for improved accuracy. The method was tested by treating Langmuir probe I-V characteristics obtained from inductively coupled Ar discharges at various pressures, and comparing the present results with those deduced by existing theories. It was shown that the plasma densities obtained by the present method are in good agreement with those calculated by the Allen-Boyd-Reynolds (ABR) theory, suggesting the effectiveness of the proposed method. Without need of manual setting and adjustment of fitting parameters, the method may be suitable for automatic and real time processing of probe characteristics.

  17. XEUS mission and instruments

    NASA Astrophysics Data System (ADS)

    Bavdaz, Marcos; Peacock, Anthony J.; Parmar, Arvind N.; Beijersbergen, Marco W.

    2002-01-01

    The X-ray Evolving Universe Spectroscopy mission (XEUS) is an ambitious project under study by the European Space Agency (ESA), which aims to probe the distant hot universe with comparable sensitivity to NGST and ALMA. The effective optical area and angular resolution required to perform this task is 30 m2 effective area and <5 inch angular resolution respectively at 1 keV. The single Wolter-I X-ray telescope having these characteristics will be equipped with large area semiconductor detectors and high-resolution cryogenic imaging spectrometers with 2 eV resolution at 1 keV. A novel approach to mission design has been developed, placing the detector instruments on one dedicated spacecraft and the optics on another. The International Space Station (ISS) with the best ever-available infrastructure in space will be used to expand the mirror diameter from 4.5 m to 10 m, by using the European Robotic Arm on the ISS. The detector spacecraft (DSC) uses solar-electric propulsion to maintain its position while flying in formation with the mirror spacecraft. The detector instruments are protected from straylight and contamination by sophisticated baffles and filters, and employing the Earth as a shield to make the most sensitive low energy X-ray observations of the heavily red-shifted universe. After completion of an initial observation phase lasting 5 years, the mirror spacecraft will be upgraded (basically expanded to a full 10 m diameter mirror) at the ISS, while the DSC is replaced by a new spacecraft with a new suite of detector instruments optimised to the full area XEUS mirror. An industrial feasibility study was successfully completed and identified no major problem area. Current activities focus on a full system level study and the necessary technology developments. XEUS is likely to become a truly global mission, involving many of the partners that have teamed up to build the ISS. Japan is already a major partner int the study of XEUS, with ISAS having its main

  18. The Space Interferometry Mission

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.

    1998-01-01

    The Space Interferometry Mission (SIM) is the next major space mission in NASA's Origins program after SIRTF. The SIM architecture uses three Michelson interferometers in low-earth orbit to provide 4 microarcsecond precision absolute astrometric measurements on approx. 40,000 stars. SIM will also provide synthesis imaging in the visible waveband to a resolution of 10 milliarcsecond, and interferometric nulling to a depth of 10(exp -4). A near-IR (1-2 micron) capability is being considered. Many key technologies will be demonstrated by SIM that will be carried over directly or can be readily scaled to future Origins missions such as TPF. The SIM spacecraft will carry a triple Michelson interferometer with baselines in the 10 meter range. Two interferometers act as high precision trackers, providing attitude information at all time, while the third one conducts the science observations. Ultra-accurate laser metrology and active systems monitor the systematic errors and to control the instrument vibrations in order to reach the 4 microarcsecond level on wide-angle measurements. SIM will produce a wealth of new astronomical data. With an absolute positional precision of 4 microarcsecond, SIM will improve on the best currently available measures (the Hipparcos catalog) by 2 or 3 orders of magnitude, providing parallaxes accurate to 10% and transverse velocities to 0.2 km/s anywhere in the Galaxy, to stars as faint as 20th magnitude. With the addition of radial velocities, knowledge of the 6-dimension phase space for objects of interest will allow us to attack a wide array of previously inaccessible problems such as: search for planets down to few earth masses; calibration of stellar luminosities and by means of standard candles, calibration of the cosmic distance scale; detecting perturbations due to spiral arms, disk warps and central bar in our galaxy; probe of the gravitational potential of the Galaxy, several kiloparsecs out of the galactic plane; synthesis imaging

  19. Evaluation of effects of groundwater withdrawals at the proposed Allen combined-cycle combustion turbine plant, Shelby County, Tennessee

    USGS Publications Warehouse

    Haugh, Connor J.

    2016-01-01

    The Mississippi Embayment Regional Aquifer Study groundwater-flow model was used to simulate the potential effects of future groundwater withdrawals at the proposed Allen combined-cycle combustion turbine plant in Shelby County, Tennessee. The scenario used in the simulation consisted of a 30-year average withdrawal period followed by a 30-day maximum withdrawal period. Effects of withdrawals at the Allen plant site on the Mississippi embayment aquifer system were evaluated by comparing the difference in simulated water levels in the aquifers at the end of the 30-year average withdrawal period and at the end of the scenario to a base case without the Allen combined-cycle combustion turbine plant withdrawals. Simulated potentiometric surface declines in the Memphis aquifer at the Allen plant site were about 7 feet at the end of the 30-year average withdrawal period and 11 feet at the end of the scenario. The affected area of the Memphis aquifer at the Allen plant site as delineated by the 4-foot potentiometric surface-decline contour was 2,590 acres at the end of the 30-year average withdrawal period and 11,380 acres at the end of the scenario. Simulated declines in the underlying Fort Pillow aquifer and overlying shallow aquifer were both less than 1 foot at the end of the 30-year average withdrawal period and the end of the scenario.

  20. Mir Mission Chronicle

    NASA Technical Reports Server (NTRS)

    McDonald, Sue

    1998-01-01

    Dockings, module additions, configuration changes, crew changes, and major mission events are tracked for Mir missions 17 through 21 (November 1994 through August 1996). The international aspects of these missions are presented, comprising joint missions with ESA and NASA, including three U.S. Space Shuttle dockings. New Mir modules described are Spektr, the Docking Module, and Priroda.